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Henryk Niewodniczański Institute of Nuclear Physics
31-342 Kraków ul. Radzikowskiego 152
lei: (4812) 3702 22 m r «, fax: (4812) 37 54 41 §1 ' , tlx: 32 2461 e-mail: kortyna%[email protected]
(High Energy Dpt.) 31-055 Kraków ul. Kawiory 26A tel: (48 12) 33 33 66 fax : (48 12) 33 38 84 tlx: 32 2294 e-mail: [email protected] Annual Report 1991
H.Niewodniczanski Institute of Nuclear Physics Kraków 1992 I, 4
RAPORT MR 1598
WYDANO NAKŁADEM INSTYTUTU FIZYKI JĄDROWEJ IM. HENRYKA NIEWODNICZAŃSKIEGO KRAKÓW, UL. RADZIKOWSKIEGO 152
Jfopię^ kserograficzną, druk i oprawę wykonano w IFJ Kraków
Wydanie I Zam. 72/92 Nakład 400 egz. Note from the editors
The material presented describing the scientific activities of the Henryk Niewodniczański Institute of Nuclear Physics in 1991 is the first annual report in several years. The arrangement of the reports from various departments reflects the present structure of the Institute and is meant to help in the future task of restructuring the Institute. Few guidelines proposed by the editorial board gave the individual departments much freedom in selecting the material and choosing the volume and format of presentation. Inhomogeneity and other flaws now obvious will, hopefully be avoided in future annual reports. We wish to express our gratitude to the authors for responding promptly and for the effort they put into the preparation of the reports. Valuable contribution by Jerzy Grębosz to the graphic outlook of this issue is warmly acknowledged.
R. Broda, L. Leśniak, P. Malecki,
Z. Stachura, H. Wojciechowski The Henryk Niewodniczański Institute of Nuclear Physics was founded in 1956. Since its very inception, the Institute carried out basic research in nuclear physics, in the condensed phase of matter studied by means of nuclear methods, in theoretical physics, and in applied nuclear physics and radiochemistry. Later on, other research fields, such as radiobiology, medical physics, nuclear geophysics and hydrology, and nuclr-ar magnetic resonance including niicroimaging, were developed at the Institute. In 1970 the Cracow Group of High Energy Physics joined the Institute. This considerably broadened the Institute's range of scientific research. The present basic research carried out in the Institute can be broadly classified into four main domains: high energy and elementary particle physics, nuclear reactions and nuclear spec- troscopy, condensed matter physics and applied nuclear physics, including enviromental studies. In all these disciplines, experimental and theoretical studies are carried out. We are also ac- tively involved in smaller projects on some selected subjects, such as medical and enviromental radiobiology, radiochemistry, fast-neutron cancer radiotherapy, thermoluminescence dosimetry and gas chromatography. Our "old" 120 cm cyclotron, U-120, has been in continuous operation for fast neutron cancer radiotherapy, radioisotope production and in studies of some selected reactions induced by alpha particles in the 23-28 MeV energy range. The "small" 48 cm cyclotron was used for PIGE and PIXE analyses and the pulsed neutron (d+d) generator was used for measurements of neutron cross sections on rock samples. The installation work of a 3.5 MV pressurized Van de GraafFaccelerator is almost completed. In August 1991 a beam of 18.6 MeV deuterons was extracted from our 144 cm isochronous cyclotron, AIC-144, currently under construction in our Institute. This opens new perspectives for medical applications. A major success was the completion and operation of a computer network linking all labo- ratories in the Institute, based on Vaxstations, The network has access to the world through CERN via the HEPNET system. In spite of severe financial difficulties, over the last year we were able to publish over 300 scientific papers, 50% of them in highly esteemed international journals. This achievement was possible, to large extent, due to international cooperation. Our main international partners are the CERN Organization, the Hahn-Meitner Institute in Berlin, the Juelicli Kernforschungszen- trum, the University of Muenster, GSI Darmstadt, CRN Strasbourg, Laboratoire du GANIL Caen, DESY Hamburg, KfK Karlsruhe, LNL Legnaro, Argonne National Laboratory, Purdue University, Brookhaven National Laboratory, Fermilab, Luisiana University at Baton Rouge, Lawrence Berkeley Laboratory and the JINR in Dubna. Since our last Progress Report was published many years ago, we decided to include in this volume a full account of our research as supplied by the authors of the contributions, avoiding any major selection. We hope that this will give the reader a good overview of the scientific activities of our staff including work performed withiu large-scale international projects. Let me finally thank all contributors for their effort to present their achievements to the inter- national scientific community, and the Report's Editorial Board for their hard and conciencious work.
idrzej Budzanowski Professor of Physics Director. DIRECTORATE
Director-General: Professor ANDRZEJ BUDZANOWSKI Deputy Directors: dr. Maryna Pollok-Stachurowa, prof. Michał Turała, dr. Piotr Malecki.
SCIENTIFIC COUNCIL
A. REPRESENTATIVES OF SCIENTIFIC PERSONNEL: Jerzy Bartke, prof. Leonard Lesniak, docent Rafał Broda, prof. Piotr Malecki, docent Andrzej Budzanowski, prof. Jacek Okołowicz, dr. Tomir Coghen, prof. Krzysztof Parliński, prof. Zygmunt Chyliński, docent Grzegorz Polok, dr. Jan A. Czubek, prof. Krzysztof Rybicki, prof. Andrzej Eskreys, prof. Jan Styczeń, prof. Jacek Hennel, prof. Michał Turała, prof. Andrzej Hrynkiewicz, prof. Michał Waligórski, docent Jerzy Janik, prof. Tadeusz Wasiutyński, docent Edward Kapuścik, prof. Kacper Zalewski, prof. Jan Kwieciński, prof. Andrzej Zuber, prof. Jan Łasa, docent
B. REPRESENTATIVES OF TECHNICAL PERSONNEL: Adam Baranowski Ewa Krynicka, M.Sc. Bronisław Czech, Eng. Mieczysław Marek Kubica Jan Godlewski, M.Sc. Piotr Skóra, M.Sc. Wiesław Iwański, M.Sc. Zbigniew Szklarz Ewa Kozynacka Władysław Wiertek. Zbigniew Król, Eng.
C. MEMBERS FROM OTHER INSTITUTES: Andrzej Białas, prof. (Jagiellonian Univ.) Wiesław Czyż, prof. (Jagieljonian Univ.) Jerzy Niewodniczariski, prof. (Academy of Mining and Metallurgy). DIVISION LEADERS
Andrzej Budzanowski, prof. - Nuclear Reactions Andrzej Hrynkiweicz, prof. - Nuclear Spectroscopy Jerzy Janik, prof. - Structural Research Jan Kwieciński, prof. - Theory Tomir Coghen, prof. - Particle Physics Jan Czubek, prof. - Applied Nuclear Physics Jacek Hennel, prof. — Nuclear Radiospectroscopy Jan Mikubski, prof. - Nuclear Physical Chemistry Edward Obryk, dr. - Reactor Technology Antonina Cebulska-Wasilewska, docent. — Radiobiology Jerzy Szwabe, dr. - Accelerator Techniques Michał Waligórski, docent. — Health Physics Zbigniew Król, Eng. - Technical Services Barbara Grabowska - Finance Division Department of
Nuclear •.: - Reactions
r '
> s
i - J DEPARTMENT OF NUCLEAR REACTIONS
Head of the Department: Prof.dr Andrzej Budzanowski
OVERVIEW:
Research on nuclear reaction mechanism was concentrated on dynamics of heavy ion reactions and hsavy fragments emission from excited sd shell nuclei. A new classical dynamical molecular model of heavy ion reaction was thoroughly tested on the example of '2S+197Au reaction at 26 MeV/A. The onset of multifragmentation was found in the 32S+58Ni system at 840 MeV by measurements of triple coincidences of intermediate mass fragments. These experiments were done in close collaboration -with Hahn Meitner Institute (Berlin) using the Argus 4rr detector partially constructed in the INP Cracow. Emission of 12C, J0Ne and 160 was studied using the a + 28Si reaction at 26.5 MeV. The beam of a-particles was provided by U-120 cyclotron. In connection with this experiment a new scattering chamber and gas detection system was installed. Subthreshold pion production and particle particle correlations were studied for 40Ar+197Au system around 40 MeV/A Nuclear temperature was detenrined for hot systems at backward an- gles of emission. These exj. -iriments were performed in collaboration with the N"ntes University using GANIL accelerator. In the frame of cooperation with FZ Julich research on spin correlation of AA produced in the (pp) anihUation was peiformed. Details of the quark structure of A hyperon were inferred. Theoretical research was concentrated on finding a possible manifestation of subnudear degrees of freedom in scattering experiments at high momentum transfer. Longitudinal and transverse spectral functions in (e,e'p) and (e,e'n) channel were investigated. In the context of regular versus chaotic motion spectral properties of multi-dimensional separable systems in the ground state region were investigated. Chaotic motion in nuclear scattering was studied for the a-f12C system. The I2C target nucleus was treated as three fir-clusters. Part of the experiments were also performed in collaboration with the Institute of Physics of the Jagiellcnian University, Cracow. PERSONNEL:
Andrzej Budzanowski, Professor — Head of the Department,
i Stanisław Drożdż, Docent — Deputy Head of the Department
Resecrch stafl (physicists):
Andrzej Adamczak, Henryk Dąbrowski, Ludwik Freindl, Kazimierz Grotowski, Professor, Elżbieta Gula, Jacek Jakiel, Piotr Kamiński, Waldemar Karcz, Stanisław Kliczewski, Zbigrjew Lewandowski, Edwin Łożyński, Marian Madeja, Maria Makowska-Rzeszutko, Jacek Okołowicz Michał Palarczyk, Artur Siwek, Irena Skwirczyńaka, Tomasz Srokowski, Antoni Szczurek, Jarosław Szmider, Henryk Wojciechowski, Roman Wolski, Michał Ziólkowski*
Technical staff:
Edward Białkowski, Janina Chachura, Bronisław Czech, Marek Gruszecki, Wiesław Kantor, Andrzej Lorenz, Arkadiusz Moszczyński, Kazimiera Fogorzelska, Janina Skałka, Stefan Sykutowski,
Administaration:
Jadwiga Gurbiel
* Postgraduate student REPORTS ON RESEARCH:
Alpha particles from the reaction 12C -j- 12C at 28.7 MeV/nucleon. A. Szczurek, A. Budzanowski, L. Jarczyk1, A. Magiera1, K. Mohring2, R.. Siudak1 and T. Srokowski
') Institute of Physirs, Jagiellonian University, Reymonta 4, PL-30-05!) Krakow, Poland 2) llahri-M^itner Institut fur Kernphysik, Berlin, 1000 Berlin 39, Federal Republic of Germany
A classical dynamical alpha-cluster model has been developed and applied in order to get inclusive energy spectra c" alpha particles produced in the collision of 32C -|- 12C at the beam energy 28.7 MeV/A. Results of the calculations are compared with experimental data. The shapes of the experimental energy spectra and the absolute normalization at forward angles are approximately described without any free parameters. The model makes it possible to distinguish alpha particles originating from the compound system and from direct processes. The spectra at forward angles are dominated by projectile fragmentation processes. The cross section at larger angles is overestimated, which is partially due to emission of parades other than alpha particles in central collisions. The evaporation Hauser-Feshbach model predicts that alpha particles emitted from the compound nucleus constitute less than 26% of all emitted particles.
Fragmentation of 12C projectiles interacting with 12C, 27A1 and 58Ni nuclei at energy 28.7 MeV/nucleon J. Czudek, L. Jarczyk, B. Kamys, A. Magiera, R. Siudak, A. Strzalkowski and B. Styczeń Institute of Physics, Jageiionian University, Cracow, Poland J. Hebenstreit*, W. Oclert, P. von Rossen and H. Seyfarth Institut fiir Kernphysik, For? -hungszentrum Jiilich, Federal Republic of Germany A. Budzanowski and A. Szczurek
Inclusive spectra of different isotopes of He, Li, Be, B, C, and N nuclei emerging from the collisions of 12C ions of energy 344.5 MeV with carbon, aluminium, and nickel target nuclei have been measured in the angular range of 4° - 36° (laboratory). Experimental yields of reac- tion products are almost the same for the different targets. The continuous parts of momentum spectra have been decomposed into three components, corresponding to direct and damped frag- mentation and to other processes, such as deep-inelastic and/or compound-nucleus reactions. At small angles (smaller than 20° in thj laboratory system) the fragmentation processes dominate whereas at larger angles they become negligible in comparison to the other components. The direct fragmentation contribution is very small with respect to the damped one. The obtained reduced momentiun widths of the direct fragmentation bumps are significantly smaller than those predicted by the Goldhaber model but agree with results obtained from other experiments at similar energies. + on leave from the Jngcllonian University, Crocow, Poland. Multifragmentation in the 32S -f B8Ni system at 840 MeV A. Sourc.il1, G^Pausch3, H_. Fuchs^ H. Homeyer1, G. Roscherti, Q. Schw.atz1, W, TerlauJ, A. Budzanowskir\ W. Kantor3 and A. Siwck3
1 Hahn-Meitner Institut, Berlin 2 Forsch'.mgszentrum Rossendorf/Dresden 3 Institute of Nuclear Physics, Cracow
Triple coincidences between intermediate mass fragments (IMF) emitted from the 3JS+B8Ni collisions where studied using the Argus 4T detector installed at the VICKSI heavy ion accel- erator. In the present experiment 79 pho9wich detectors were used. These covered the forward cone from 3 to 32 deg as well as some selected larger angles. The AE counters consisted of 0.5 or 1 mm Pilot U, the E counters of 12 mm BGO or NE 115 scintillators. Solid state detector telescope at 29 deg recorded the fragments with good energy and Z resolution and served as a trigger detector. Its det xtion. window of IMF fragments was set on masses from 6 to 30 and velocities from 0.6 to 4 c.n/ns. Two other IMF were stopped in the AE layer of the Phoswiches. The distinction from a-particles and protons was obtained by the time of flight signal, but no more precise information on,Z or A could be extxueted. According to previous work [1] it was assumed that the 3 emitted IMF could be ascribed to the original excited A = 60 system. The obtained a«imuthal angular correlation between two IMF's (one being detected by the semiconductor telescope) are shown in Fig. 1. The experi- mental data are compared to the prediction of statistical multifragmentation models of Gross [2] and Bondorf [3]. In Fig. 2 the same data are compared with the prediction of the sequential decay models assuming different mass asymmetries in the first step of emission and different mass width. We notice that better agreement was obtained in terms of the multifragmentation models what allows us to put forward a conjecture that the observed angular correlation can be ascribed to the onset of the multifragmentation process.
Theory (MF)
.°. 20
CD +-* O
O Fig. 1. Distribution of ielntive tutimuthal o angle DF between one of the IMFs in the phoswidi detectors and the semiconductor 100 200 telescope at 29°. Curves: jnultifragmenta- tion simulation with the models of Gloss [2] or Bondoif[3). 0.5 <*SYM2~ 0.5 20 MABR «. 0.02
0
ASYW1~ 0.5 ASY>^2~ 0.5 20 MADR «10 3 ci O o ASYM2- 0.5 Ł 20 MABR •> 0.1 -jf— " c D O U 0 * i-
ASVW2- 0.1 Fig. 2. Distribution of relative uginiiil/iłJ an- MABR g/e Cc/! fi#. /J. CJirctea: experiment; IM- togra.ms: sequential fission simulation willi mean mass naymmetiy ASYM1(2) of the 0 fust (second) fission (ASYM — (A,)/A, for um 200 each fission slap separately) RIKJ masB width
MABR - References: [1] H. Morgenstern et al., Phya. Rev. Lett. 52 (1984) 1104 [2] D.H.E. Gross, Phya. Lett, B203 (1988) 26 [3] J.P. Bondorf et al., Nuci. Phys. A444 (1985) 450 The work was partially supported by the Committee of the Polish-German Scientific and Technical Cooperation Grant No BO-X081.4. Direct projectile break-up in the 32S -}- 197Au collisions at E,afr = 823 MeV 0. Schwarz1, H. Euchs1, H. Homeyer1., K. Mohring1, A. Siwek3, W-.Terlau1 and A. Budzariowski2 1 Halin Meitner Institut, Berlin, Germany 3 Institute of Nuclear Physics, Cracow, Poland Fragments with masses higher than 4 may originate from the direct projectile fragmentation. The dynamical molecular model of Mohring et al, [1] predicts such partitions in the projectile fragmentation. In the present investigation we have chosen the collisions of 32S with 197Au nuclei at 26 MeV. Projectile-like fragments (PLF) were detected by the Argus 4ir detector equiped with 123 Phoswich detectors, Angular correlations of a- particles and heavier projectile-like fragments (PLF) with PLF's of Z>2 were measured. The obtained results are compared to the predictions of the dynamical model [1]. As can be seen from Fig. 1 the agreement Is remarkably good even in absolute magnitude. This suggests that for the case of emission of two PLF with Z>2 the contribution of the sequential decay is minor. This conclusion is supported for the example of correlated C-C pairs, by comparing with branching ratios for thu statistical decay of excited primary Mg fragments. We have measured both the C-C, and O-em channels. The measured cross section for the last channel with 160 at 14° is 6 mb/sr. For statistical decay of Mg into two C-C according to Wieland et al. [2] and Sandorn et al. [3] the cross section should be ID times smaller. This is at variance with our findings 21 mb/sr for C-C pairs with one detector at 14° . I ¥ Fig.l. Angular distributions of all projectile- like fragments with Z>2 coincident with quasieJastic projectile-like fragments as indi- cated detected at 14.4° (dashed line). Data points: measured double-diffettntial cross sec- tions. Histograms: prediction of the dyn&mi- cal model. References: [1] K. Mohring et al., Phys. Lett. B203 (1988) 210 [2] Wieland et al., Phys. Rev. C9 (1974) 1474 [3] Sandorfi et al., Phys. Rev. Lett. 45 (1980) 1615 This work was partially supported by the Polish-German Agreement of Scientific Cooperation Grant No BO-X0814. Nucleonic effects in quasi-elastic electromagnetic response. M. Buballa1 , S. Drożdż , S. Krewald1 and J. Speth1 1Ltistitut fur Kernphysik (Theorie) Forschungszenlrum Jiilich GmbH., D-5170 Jiilich, F.R.G. An interpretation of lepton or hadron scattering experiments on nuclei in connection with a possible manifestation of aubnuclear degrees of freedom requires very precise estimations of conventional many-body effects in nuclei. Paradoxically, it appears, however, technically more difficult to reliably incorporate such effects than the more exotic ones. In the RPA type approach to the nuclear,structure effects, especially at higher momentum transfer q, it is necessary to include scattering states in the continuum to account for the final state interaction. The related problem is the effective interaction. To ensure a natural momentum cut-off one should use the finite range forces. Moreover, the effects beyond mean field, the 2p2h correlations, have been proved [1] to influence the energy strength distribution also at higher q. Here we report on our extensive analysis [2] of the above mentioned effects in connection with the quasielastic electron scattering on nuclei. In particular, the difference between longitudinal and transverse responses is emphasised. Since the experimental data are most reliable for light systems, because of weak influence of distortion effects there, we refer here to 12C. 0.03 I8C. q-yOO MeV/c C. q=300 McV/c •Si 0.02 ' 0.01 {/ 12C. (1=400 MeV/c • UJM, 1ZC q=400 MeV/c 'in, 0.01 • 0.00 "C, q=500 MeV/c 'C, q=500 McV/c 0.01 - 0.00 40 >0 120 100 Encrcr fUeV] Fig. 1. Longitudinal (Lh.s.) and transverse (r.h.3.) response functions for C calculated within continuum RPA using G-matrix as an effective interaction (thick line) and without interaction (thin line) in comparison with the experimental data. Fig. 1 displays the continuum response for its longitudinal (l.h.s.) and transverse (r.h.s.) components. The thin line refers to the free response and the thicker one to the full continuum KI'A response where the G-matrix derived from a meson-exchange potential has been used as an effective interaction. As one can see, including interaction improves, on the average, the agreement with experimental data (bars). The effects of interaction decrease, however, with increasing q and an ovcrestimation of the data for the longitudinal response at q = 500 MeV/c becomes obvious. The transverse response, on the other hand, is underestimated and this opens some room for meson-exchange effects and A excitation. References: [1] S. Drożdż et al., Physics Reports 197 (1990) 1 [2] M. Buballa et al., Ann. Phys. 208 (1991) 346 Kinematic dependence of final state interaction in the (e,e'p) reaction. M. Buballa1, S. Drożdż, S. Krewald1 and A. Szczurek 1 Institut fur Kernphysik (Theorie) Forschungszentrum Julich GmbH., D-5170 Julich, F.R.G. The coincidence cross section for the eleetrodisintegration pf 4He has been measured at NIKHEF-K [1] for two values of the momentum transfer q in. a broad range of the missing momenta pm — p — q. The data are presented as the so-called spectral function which under the assumption of factorization of the cross section represents the momentum distribution of protons in the4 He nucleus. The spectral functions derived from the data are found, however, too strongly depend on the kinematics chosen. Even though a sophisticated ground state wave function was used this fact could not be explained by a factorized distorted wave impulse approximation (DWBA). Therefore we concentrate on final state interaction effects which may partly be caused by the scattering in a mean-field and partly by genuine two-nucleon rescattering processes. The spectral function has been obtained [2] in an analogous way as the experimental one, i.e. by dividing the general coincidence cross section by the off-shell electron-proton cross section calculated according to the current-conserving prescription [3]: s[Pm'E) = 7E' Fig. 1 shows the calculated spectral functions for both kinematics compared with the ex- perimental data. The influence of mean-field distortions, measured as a difference between the dotted and dashed lines, depends on the kinematics. A major effect is found for kinematics 2 which corresponds to a smaller transferred momentum. This can be understood in terms of the following simple arguments. The longitudinal structure function iijr, can be written s.3 (2) with Aijj being independent of q as a combination of Clebsch-Gordan coefficients and spherical harmonics and |^l/a(r) (3) where 8 corresponding behaviour is illustrated in the insertion to Fig. 1 (dotted line) for 1 = 2, j = 3/2 and J = 2. Switching on the attractive mean field the wavelength in the interior of the nucleus hecoin.es shorter and the maximiun of Fijj is shifted to higher q as shown by the dashed line. In this way the cross section is reduced for lower and enhanced for higher values of the momentum transfer. A similar argument applies to the transverse structure function. The other important effect seen in Fig. 1 is due to the two-body rescattering. One observes a systematic reduction of the spectral function as compared to the mean-field result. The effect is again stronger for kinematics 2 consistent with the lower transferred momenta. One should also notice a very good agreement of the theoretical results with experimental data for smaller missing momenta. At larger momenta the calculated spectral function underestimates the data. This signals an importance of two body correlations and meson-exchange currents which are not included here. 10 10 "JO I/) -10 10 • -u 10 ' . . . 0 100 200 300 0 100 200 300 400 Pj MeV/c ) Fig. 1. Spectra] function S(pm) from *3e(e,e p)*He reaction for two kinematics: left hand side Qe = 70" (q = 431 MeV/c) and light hand side 0, = 36° (q = 250 MeV/c). Both, the experimental data [l] and theoretical results are presented. TJie dotted line represents the plane-wave approximation result with the recoil correction and the dash-dotted without. The dnahrd line includes ne&n-field distortions and the solid line includes also rescattering effects. The upper insertiuii illustrates the q-dependence of the function defined by eq. 3. The dotted line shows the result without any final state interaction. In tiie dashed line the interaction is included on the mean field level. References: [1] J.F.J. van den Brand et al., Phys. Rev. Lett. 60 (1988) 2006 [2] M. Buballa, S. Drożdź, S. Krewald, A. Szczurek, Phys. Rev. C44 (1991) 810 [3] T.de Forest, Jr., Nuci. Phys. A392 (1983) 232 Influence of coupling between (e,e'p) and (e,e'n) channels on longitudinal and transverse spectral functions. M. Buballa1, S. Drozd/,, S. Krewsild1 and A. Szczurek 1 Instititt fiir Kcrnphysik (Thoorie) Forschungszentrum Jiilich GmbH.,D-5170 Jiilich, F.R.G. The general coincidence cross section in the one-photon exchange approximation can be expressed ns (ij: cos 2 Fig. 1. Upper part: Missing mo- mentum dependence of the lon- gitudinal (left iiand side) and transverse (right iiand side) spec- trul functions for 0e = 70°. TJie mean Held result is repre- sented by the dahsed line and the full (RPA) result by the solid line. The dotted line ignores the proton-neutron coupling in the two-body interaction. Lower part: (e,e'n) versus (e,e'p) cross sections for the same kinemat- ics separated into the longitudi- nal and transverse parts. 0 100 200 300 100 200 300 pjM.V/c) pjHtV/c) 10 of the longitudinal spectral function (solid line) with respect to the mean-field result (dashed line) is almost entirely caused hy the proton-neutron coupling. As displayed in the lower part of Fig. 1 this simultaneously creates the (e,e'n) longitudinal cross section wliich is vanishing at the mean-field level. The corresponding transverse part is little influenced hy such effects. In this context it is interesting to make such a separation for kinematical configurations of the Saclay experiment [3]. Fig. 2 shows the | q j dependence of the longitudinal and transverse spectral functions for two different energy transfers of 98 MeV (left hand side) and 62 McV (right hand side) at fixed missing momentum of 90 MeV/c [4]. Since the related experimental data correspond to parallel kinematics, one pair of such points can he assigned to each of the transferred energies. The calculated longitudinal spectral function is strongly suppressed with respect to the transverse one, consistently with the tendency seen in the experimental data. This suppression originates mostly from the proton-neutron rescattering processes and, because of this, it decreases with increasing q, which is seen when looking at the - itio between the two spectral functions. 150 150 w = 98 MeV o>=$2MeV 100 V o 50 50 n | 0 r ^„ r r~ 230 300 350 400 MO 200 250 300 A1O «0 450 q (M.V/e) q (U.V/c) Fig. 2. Momentum transfer dependence oftkr. separated spectral functions for two different energy transfers ui. The dashed lines represent the mean-field result and the solid ones include rescattering effects. The existing experimental data [2] are denoted by the open squares for the longitudinal and closed ones for the. transverse spectral functions. References: [1] S. Frullani and J. Mougey, Advances in Nuclear Physics, 14 (1984)) 3 [2] A. Magnon et al., Phys. Lett. B222 (1989) 352 [3] J.F.J. van den Brand et al., Phys. Rev. Lett. 60 (1988) 2006 [4] M. Buballa et al., Phys. Rev. C44 (1991) 810 Density dependent rescattering effects in the (e,e'p) reaction. S. Droźdż, S. Krewald1 and A. Szczurek 1 Institut fiir Kernphysik (Theoric) Forsi'hiiiigsmitnini Jiilich CJmM)., O-filVU .IUIMII, F.R.G. A possible medium modification of tin* niuliMin formfartor is one of \hv. mns( inlrigiiitig bill not yet fully understood pliciuiinfiia. Nti ron-.ciisus lias been attained as In wbi'llior llu- obju-rved peculiarities in the cross section, esjx'rially tli'1 «iippr 11 component, are explainable entirely in terms of the conventional nucleonic degrees of freedom or if the quarks manifest their presence as well. The MIT [l] and N1KHEF-K [2] groups reports about the transverse longitudinal relative enhancement detected in 12C are interesting in this connection. The observed enhancement turns out to be stronger for the s-shell and that for the p-shell. Here v/c explore the problem of two-body rescattering effects which have been found to be important for inclusive processes, even at comparatively high momenta. In exclusive processes the coupling between protons and neutrons causes a depletion of the cross section in the (e,e'p) channel. This effect may also depend on the density. Intuitively one would expect that the probability for rescattering is enhanced with increasing density. One should, however, remember that the effective interaction in the relevant (TT1) channel becomes weaker at higher density. Which of the two effects dominates? For parallel kinematics the coincidence cros3 section is a sum of the longitudinal and trans- verse components only. Their q dependence corresponding to three different calculations is illustrated in Fig. 1. The contributions for the p and s shells are separated. As is clearly seen the rescattering processtv are more effective in the Sj /2 shell. Moreover, in the longitudinal cross section the charge-exchange effects are dominant in tliis respect and lead to its reduction. The experimental data of ref. [1] are discussed in term3 of the L/T ratio divided by the same ratio for the distorted-w?»ve impulse approximation. In such a double ratio the off-shell p(e,e')p cross sections cancel out and the result is identical to the same ratio of the spectral functions. The analogous ratios extracted from our results are displayed in Fig. 2. At the momentum transfer which coincides with the measured values (q=400 MeV/c) this corresponds to 0.79 for the p-shell and 0.71 for the s-sheli. This is to be compared to experimental [1] 0.89±0.09±0.12 (the same ratio extracted from the data of ref. [2] is 0.67±0.22) and 0.61±0.08±0.07, respectively. In the kinematic region the difference of 10% in the calculation-for different shells is caused entirely by the proton-neutron coupling. Without this coupling both shells give almost the same result (about 0.75). This means that the longitudinal/transverse suppression and in particular the shell dependence of this effect does not necessarily provide evidence for a medium modification of the nucleon formfactor. ,-5 transverse transverse 8 1/2 (u • f, "10 . 10 \ longitudinal 200. 300. 400. 500. W0. 400. 500. q (MeV/c) q (UeV/c) Fig. 1. Tfie separated pa/3 (l.h.s.) and SJ/J (i.h.s.) contribmions to the transverse (upper part) and longitudinal (lower part] components of the (c,e'p) cross sections (in [fm3/Mcl'/sri]) in 12C for parallel kinematics. The dotted lines display the mean field result, df-ihrd lines the RPA result with the proton-neutron coupling discarded and the solid lines the full RPA result. 12 ;.& P3/2 S1/2 o C.2 .500. '100 f.OO 200 300 400. ^00. q (McV/e) q (McV/c) Fig. 2. Tlić RPA longitudinal/transverse talio divided by Ihe same ratio circulated on the mean Reid level. The dashed Hue displays ihc same quantity with the proton-neutron coupling in RPA ignored. The experimentnl dala arc those ofref, [l]. References: [1] P.E. Miner et al., Phys. Rev. Lett. 59 (1987) 2259 [2] G. van der Steenhoven et al., Phys. Rev. Ld(t. 57 (1986) 182 Coupling between (e,e'p) and (e,e'n) channels in the quasi-elastic domain . S. Drożdż. S. Krewald1 and A. Szczurek 1 Lnstitut fur Kernphysik (Theorie) Forschung3zentnim Julicli GmbH., D-5170 Jiilich, F.R.G. In recent years the (e,e'p) reaction has been successfully exploited in order to understand the nuclear structure. In the juasi-free domain momentum distributions of valence nucleons have been extracted from the data with great precision. The alternative (e,e'n) channel has never been studied experimentally in the quasi-elastic region. First detailed studies of this channel have recently been proposed by the NIKHEF-K group [1]. In the present note we quantitatively explore this problem. The most natural frame for studying (e,e'x) processes is provided by the coupled channel method (CCM) on the basis generated by the nuclear mean field. In the present analysis we apply the recently developed method [2] to simultaneously account for the mean-field distortions and two-body rescattering processes. The residual interaction is specified in terms of the G-matrix [3] derived from the Bonn meson exchange model. The mean-field part of the Hamiltonian is represented by a local Woods-Saxon potential which reproduces the ground state. The free nucleon formfactor in its standard dipole parametrization is used. Fig. 1 shows contributions to the (e,e'p) and (e,e'n) coincidence cross sections coming from 12 p3/2 and Si/2 shells in C at four different q values and for the energy transfer corresponding to the position of the quasielastic peak. These cross sections are plotted versus the angle between the momentum p of the knocked-out nucleon and the transferred momentum q. Thus the small angles correspond to the parallel kinematics where the interference terms VLT an^ "VTT disappear. As is seen, the rescattering processes (the difference between CCM and pure mean field results) dramatically enhance the number of emitted neutrons at the expense of reduced proton cross section. Also, the proton angular distribution is modified due to the coupling between the (e,e'p) and (e,«'n) channels. Moreover, such effects are stronger for the s-j/2 than for the p3/2 shell. The extra emission of neutrons caused by the rescattering turns out to be more 13 probable for the s-shell, i.e. at higher densities. The effect is more important for the longitudinal cross section. The transverse cross section remains much less affected by such wflects because in this channel the electron couples to thft neutron already on the mean field level. Of course, increasing q one gets closer to the mean field picture because the residual interaction becomes weaker. r> 10-5 1 0" - I0"7- io-9- icH , q==200 MeV/c = 200 MeV/cj 1/2 10-" 10-" 5 , q-300 MeV/c 10" p3/2 , q = 300 MeV/c 1/2 7 10-7 10- 9 10-9 10- 10-11 10" , q = 400 MeV/c '1/2 , -q-400 MeV/c 10- 10-9 10- 10- p,,, , q-500 MeV/c 10" s1/3 , q-500 MeV/ci 0 30 GO 90 i?C ISO 180 Ó 30 60 90 120 1^0 180 Fig. 1. The separated p3/a (l.h.s.) and SJ/J contributions to the (c,e'p) and (e,e'n) cross sections (in[fm3/MeV/sr3]) in the quasielastic peak of nC plotted ns functions of the nuckon angle measured with respect to the direction of the momentum transfer q. The thicker lines currcspond to protons and the (/ii'ner ones to neutrons. In each case the dashed lines describe the mean Reid results and the solid lines include a/so the rescnttering e/Tects. 14 References: [1] G. van der Steenhoven et al,, Bates proposal. [2] M. Buballa, et al., Ann. Phys. 208 (1991) 346 [3] S. Krewald, et. al., Phys. Rep. 161 (1988) 103 EO Excitations in 5tiNi S. Drożdż, E. Migli1, J. Speth1 and J. Wambach1. 1 Institut fur Kernpl)ysik (Theorie) Forschungszentrum Jülich GmbH., D-5170 Jülich, F.U.G. Amony the elementary modes of nuclear excitation, the giant resonances are of special im- portance since they carry /aluable information on bulk properties of nuclei and, through ex- trapolation , of nuclear matter. Of particular interest in this connection is the breathing mode since its excitation energy is directly related to the compression modulus Kyi of finite nuclei and, thus, also to the nuclear matter value KM . The most reliable values of Km are extracted from the experimental information involving the giant monopole resonances (GM0 R). It is therefore highly desirable to have a systematics throughout the periodic table. Doubly closed-shell nuclei are especially important because of their simple structure. Some of them, like B8Ni or 132Sn are, however, unstable to electromagnetic or weak decay (68Ni has a half life of 6.1 days) and their measurement is only accessible in inverse kinematics. One purpose of this note is to provide theoretical estimates of the breathing mode cliaracteiistical in this nucleus. To estimate the total width of the resonance one should solve the full second RPA (SRPA) equations [i] directly in nuclear continuum. This, however, is not possible at present for technical reasons. Furthermore, to acliieve convergence of the SRPA solutions with respect to the single- particle basis one necessarily has to use the finite range interactions, for instance those generated by the one-boson exchange models. Wliile such an approach works well in most cases, the rentroid energy of the state which is of basic interest here, i.e. the breathing mode, comes out too low by 2-3 MeV in hea 'ier nuclei. Erom a phenomenological point of view, Landau-Migdal type zero-raiige effective infractions are more successful. For these reasons and in order to obtain physically meaningful predictions, we perform the following analysis [2], First, we solve the continuum RJC*A equations with the zero-range density dependent inter- action [3]. The resulting excitation energy (multiplied by A1/3 ) of the breathing mode as a function of the mass number is shown in Fig 1. On average one finds satisfactory agreement of the calculated results and the experimental data. The predicted centroid energy in 56Ni is about 18 MeV. To combine the spreading and escape width we add them incoherently. This means that the underlying subspaces of the Hilbert space are assumed to be orthogonal, which is a reasonable assumption. The effect of the nuclear continuum is to introduce a width on the lplh level. This effect can be included in calculations with a discrete single-particle basis by taking the ph energies ep)t as complex. The accuracy of the procedure can be verified by comparison with exact continuum calculations. Therefore, the most economic way to include both the escape and the spreading width is to solve the SRPA equations with the complex ph energies, with the imaginary part determined by the free continuum solution for each ph configuration independently. This procedure accounts for an energy dependence in the escape width. B6 The effect of spreading on the GM0R in Ni is illustrated in Fig. 2. On the level of continuum RPA (dotted line) the resonance has a FWHM of about 2 MeV.'Inclusion of 2p2h effects with the finite range forces spreads it further (solid line) with a FWHM of 5 MeV. In particular, the distribution develops a high energy tail. As a consequence, about 83% of the total energy weighted sum rule remains in the peak region. 15 ..".Mil A h % 1- |ł t Pig. 1. The excitation energy of the breathing mode multiplied by Al^s as a /unction of the mass number (A). The solid line corresponds to the continuum RPA results and the dashed O Cii Ni Zr Sn I'll -., . y .-.4 ,-(• łl^T- >.^_™^—-t f.1.,--,.-,-^-. •> 1ft: J '>3 4 ftO 4 ŁO SCO •.'« fUd line to the free (no interaction) response. A'" 56 Ni 0+ T=0 Fig-. 2. The breathing mode straight distribution in B0Ni offer including the continuum and spreading (SRPA) ef- fects (solid line). For comparison, the dashed line ignores the ladder and bufe- ble diagrams in SRPA and the dotted line includes the escape width only. 10 References: [Ij S. Drożdż et al., Pliys. Rep. 197 (1990) 1 [2] E. Migli et al., Z. Phys. A340 (1991) 111 [3] G.A. Rmker and J. Speth, Nuci. Phys. A306 (1978) 360 Spectral properties of multi-dimensional separable systems in the ground state region, S. Drożdż and J. Speth1 aInstitut fur Kernphysik (Theorie) Kernforschtuigszenlrum Jiilich GmbH. D-5170 Jfilidi, F.R.G. The nearest-neighbour spacing (NNS) distribution and the A3 rigidity provide a commonly accepted tool for studying the global properties of nuclear Hamiltonian in the context of regular versus chaotic motion. Such an analysis is, however, usually based on a very limited number of states (typically 100-400). This has to be, taken with the particular care because the above statistics are to be understood as the asymptotic properties. It turns out that the Gaussian Orthogonal Ensemble (GOE) type shapes in the region close to the ground state may reoult not only from the dynamical repulsion reflecting nonintegrabiiity but also from the ldneinatical repulsion which takes place in integrable systems. Especially critical in this sense are the low- energy statistics in higher dimensional problems because the number of states involved per dimension is very small there. We study the statistical fluctuations for various Hamiltonians of different dimensionality and for different strings of eigenvalues. 16 6.0 4.0- 2.0- 0.0 4.0- 2.0- 0.0 4.0 CO \< 2.0 0.0 4.0 2.0 -.•--" 0.0 4.0 2.0- 0.0 y 0 20 40 60 80 100 Fig. 1. NNS distribution and Aa statistics for different five-dimensional intcgrnble problems using a string of 400 low lying states. Since most nuclear near ground state phenomena are well described by the harmonic ap- proximations we refer first of all to the harmonic oscillator potential (h.o.) [1]. Fig. la shows NNS distribution (histogram) and A3 statistics for the five-dimensional uncoupled h.o. potential with irrational ratio between the frequencies, using 400 lowest lying states. Tłu? histogram rep- resenting NNS distribution is fitted (solid line) with the generalized Wigner distribution which determines the repulsion parameter r. The other figures illustrate a role of anharmonk isHucts: in (b) the x2 h.o. potential in one direction is replaces with x4 , in (c) all directions are bound with x* , in (d) the h.o. in one direction is replaced with | x |3/2 and in (e) all five directions are bound with | x |3/2 type potential. The dotted line represents Poisson distributions and the dashed lino GOE predictions. It, thus, appears that the low-energy .spectral fluctuations in highcr-ditnoDsioiial separable 17 hamiltonian systems may show a level repulsion typical for chaotic systems. This tendency enhances with an increasing dimensionality of a problem. For that reason, certain empirical near-ground state statistics may lead to conclusions overefitunating the amount of chaos. References: [1] S. Drożdż and J. Speth, Phya. Rev. Lett. 67 (1991) 529 Chaos in nuclear scattering J. Okolowicz. T. Srokowski and S. Droźdż Understanding of nuclear dynamics in the context of regular versus chaotic motion is nec- essary to specify the properties of the underlying phase-space and to deterniine the nature of the nucleus as a whole. It puts also the related considerations into more general and unified frame. The converse is also true. Studying nucleus from such a perspective may improve our understanding of general complex dynamical systems and, in particular, may help in building a bridge between classical and quantum mechanics for classically chaotic Bystems. A? a contribution to this kind of activity we study nuclear scattering problem. The nuclei are specified in terms of the alpha cluster model [1] with a-a interactions derived from the TDHF calculation [2]. One observes chaos, i.e. strong sensitivity on the impact parameter already for a + 12C system even freezing all the distances among a-particles within the 12C target (see Fig. 1). Calculating the lifetime of a composite o + 12C object by summing up all the trajectories which still remain in the interaction region after a given- time one finds characteristics typical for an exponential decay for time period of the order of 10~12 s. Such behaviour resembles a decay of quantum mechanical resonance, Q Li-I I I lli_l'l I I I I l_l I I I I I I Ml ULJ Lj-l-l'l I'l'l I I I I I I 1 I I I L*l III |\ i i i i . I i-i . i i I I IT 5.40 5.42 —.—r" — -"I1 '•";• .4 " ' . (c) ;*?*• \ V t r- -~~* •A • ;?. .^? Fig. 1: The deflection function (scatter- '•_ i ing angle t9 vs. impact parameter b) for 1U.U.U l.l.J-l_l-ńl-l_iJU-1-J-t.Li.jU.Xi-l.JL E = 3.6 MeV presented with different 5.1176 5.H77 5.373 5.379 5.080 impact parameter resolutions b [fm] IB Chaoticity of a dynamical system means that stable and unstable manifolds intersect each other in nn infinite number of points revealing a very complicated structure. In the scatter- ing problem trajectories with initial conditions close to the unstable manifold escape instantly whereas those on the stable one dwell within a limited region forever. Set of points of the phase space trajectory converges to after a long evolution time is called the transient [3]. In the vicinity of transients trajectories are exponentially unstable (positive Lyapunov exponents) and the set of initial conditions leading to the transient has fractal dimension d. The probability that a trajectory remains within the nuclear interaction region after time t is proportional to exp(~f/r). The trajectory can leave that region when it falls into the hole between two folds of the stable manifold. Since the density of these holes is proportional to 1 — d, where d is the dimension, and the Lyapunov exponent A is the mean velocity of the escaping flow, the average lifetime r can be expressed by: 1/r = A(l — d) [4]. Calculating explicitly A and d one finds a satisfactory agreement of this prescription with the direct way of estimating lifetime. For longer time periods relating the two independent methods suggests grouping the trajectories into three different categories labeled by different A. A. method based on phase space averaging is introduced which allows efficient calculation of A even for short trajectories. The resulting procedure offers a possibility to determine the cross-section for a compound nucleus formation, as a function of bombarding energy. Of course, to obtain realistic estimates more degrees of freedom have to be involved, for instance by allowing the constituents to move. At higher energies even this is not sufficient but the effect of missing degrees of freedom can be •compensated by introducing a stochastic force. References: [1] D. Provoost, F. GrUmmer, K. Goeke, P. G. Reinhard, Nuci. Phys. A431 (1984) 139 [2] J. Okołowicz, T. Srokowski, Acta Phys. Polonica B22 (1991) 653 [3] C. Grebogi, E. Ott, J. Yorke, Physio.a 7D (1983) 181 H. Kantz, P. Grassberger, Physica 17D (1985) 75 [4] J. P. Eckmann, D. Ruelle, Rev. Mod. Phys. 57 (1984) 34 Geometrical versus semiclassical quantization E. Caurier1, S. Drożdż, J. Okołowicz and M. Ploszajczak 1 Centre de Recherches Nucleaires, F-67037 Strasbourg Cedex, France. The quantum mechanical problem is rarely exactly solvable and some kind of approximate solutions is necessary. The semiclassical methods are of primary importance in this connection but their applicability encounters serious technical difficulties when the phase-space displays stochastic structures [l]. The other class of approaches, technically similar is based on the time- dependent variational principle (TDVP). The idea is to reduce the infinite dimensional Hamilton problem by restricting the number of degrees of freedom to a few most relevant. The resulting equations of motion for wavefunction ift(x\ t) are in general nonlinear and the stationary solutions cannot be found. The wave packed type solutions for bound states xj>(z\ t) — if>(x\ z(t)) have to be localized in space. Then the time evolution generates an additional phase ahd the full solution becomes: c ; t) = V' (z; z) = tf(*; z)exp(i|d('{V|iMt.|V'))exp(-i(V|H|V')t/ft) (1) 19 where z(t) {^t(t),... ,z2m(t)). Tim first exponent in (i) depends solely on the geometry of a trnjcrlory in I ho parametric space and can be identified with the geometrical phase [2- 4). Because of the gangeinv;>,riance of the geometric phase it is natural to extract V'c(a:; z) ~ rf>n(x; z)c>q>( i(i/'|/?|(/)'/^)> l'ic g«»ó---««-v«'^»''int component tf>n incorporating the geometrical phase. Tin: principle of regularity and single valucdncss (Il.SV) [2] is then imposed on ip*" and provides a conr.istenl prescription for selecting energies of quantized, states [5j. The quantum SU(3) spin system [()] is very advantageous in testing various approximations because it mimics the essential ingredients of shell model and is exactly solvable. In classical, large -TV limit given by TDHP the model is non-integrable. The SU(3) model consists of JV distinguishable fermions, labelled by index n, each of which can be in three, N-times degenerate single-particle levels having energies c0 ~ — f, fi ™ 0 and t2 = f. The Hamilton operator is: 2 k-0 h,l=O where Vhi — V(l - Ski), V < 0, and Ń;,i — £]„ ^l^nl- The mean field limit is obtained with the Slater determinant: 1^(^(0,-2(0) = exp[z1(0Ńlof z2(O^2o]|*l = 0,r2 = 0) (3) labelled by two complex particle-hole (p-h) amplitudes z\ and z^. The classical Iiamiltonian // can now be identified with (J.i{z)\H\\li{z))/{tj>{z*)\ij)(z)). Working with the normalized states it is convenient to change to the parameters /?,• = z,/\f\*-|- z^z^ -f ziz\ and separate out their real ( 3 (x = NV/e) has four degenerate miniuia .separated by saddle points. For large /V, the quantum motion is restricted to the narrow region in the phase space around each of the minima of V. The high barriers among them prohibit strong mixing and the description of quantum system using a single, time- evolving Slater determinant around each minimum of V separately can be justified. However, for snmU number of particles even the lowest excited state appears close to the saddle point and, therefore, mixing of the Slater determinants in. the quantum wavefunction cannot be excluded. These quantum correlations are absent in the TDHF-lield, One could approximate them by ; introducing projected manifolds {^,,,(|3iift)) ^ {i'<71 20 = 00 N- 16 N= 12 g.i: .rumcnrć surfaces for different particle numbers n.s calculated for the state |l+.f). References: [1] M. C. Gutzwiller, J. Math. Phys. 12 (1971) 343; M. V. Berry ct a/., Ami. Phys. (N.Y.) 122 (1979) 26 ' [2] K.K. Kan et a/., Nucl. Phys. A232 (1979) 109; S. Drożdż el oi., Phys. Lett. 11513 (1982) 161 [3] Y. Aharonov and J, Anandan, Phys. Rev. Lett. 58 (1987) 1595 [4] M. V. Berry, Proc. Roy. Soc. London 392 (1984) 45 [5] E. Caurier ei a?., Acta Phys. Polonica 22B (1991) 389 [6] R. TJ. Williams and S. E. Koonin, Nuci. Phya. A391 (1982) 72 Dynamical description of transition probabilities E. Caurier1, S. Drożdż, J. Okolowicz and M. Ploszajczak 1 Centre de Recherches Nucleates, F-G7037 Strasbourg Cedex, Prance. The time-dependent variational approacli based on geometrical quantization has been ex- tensively used to calculate the energies of nuclear vibrational states. Recently, on the basis of relationship between TDVP and generator coordinate method [1], it has been successfully adopted to the calculation of transition probabilities between different quantized states [2], Here the efficiency of this method is analysed in the exactly solvable SU(3)-quan(um spin system [3]. For its definition and mean field representation see the previous report or [4]. As before the quantum correlations beyond mean field are introduced by defining projected manifolds (V'o-^JO^I,ftz)} = {P^^^iPu&)}i where the projection operator is defined as ~ (1 + with = 1i{-pi,Pj) and {ip,. t.} and {ip } separately, the time-evolving wave-packet is a superposition of Slater deter- minants around each of the four minima of potential V [4]. With these variational manifolds 21 the equations of motion tako form: ^^J [U - 1,2), (i) where $ij are Poisson brackets. Time periodic solutions; for/3(f) are selected to construct i and, then the quantization condition is employed to select physical states and their excitation energy. A stationary state wavefunction can be projected out by constructing time-averaged wavefunction for a given quantized stale \n): /r"rf/V;(/J(O)( /^'^'W J«WrtU>) (2) distingu;shes ainong different periodic trajectories corresponding to different states. Using (2) one can calculate the transition probabilities between any two states \n) and Ja'), and for any operator F. Fig. 1 shows (he results for diagonal and off-diagonal matrix elements of ś = Nu - N0Q and t — 7V22 + Ńn - 2,/Voo among first two excited states |1}, |2) and the ground state |0). The calculations are performed for various particle numbers in the manifolds {ip+.f.}, {^ } at x ~ 10. Solid lines exliibit results of JISV calculation!; in the projected manifolds, whereas dots show exact quantum results. The uppermost plota in Fig. 1 exhibit the excitation energies <1|#|1) and (2|J7|2) (in units off) for states with (++) and (--) parities. The dashed line in the upper figure for t/»++ denotes results of random-phase approximation (RPA) for energies of onp.-phonon states. Notice, that until N a 50, the agreement, between the RPA and exact results is very good. Dashud-dotted line in the upper right figure for V'-- presents results of the quantized TDHF. This is an improvement over RPA in the region .40 < N < 50. For smaller number of particles (jV < 40) one fmds deviations mainly for the negative parity states. The positive parity states in turn, are still well described by TDHF for all N. In general, the agreement between exact 5U(3) results and the large-TV limit of SU(.'J) is excellent until JV ~ 40 for all diagonal matrix elements including those of 3 and i. Below iV ~ 40 this good agreement deteriorates but can be recovered after the quantum correlations due to the parity projection are added. The agreement for the oiV-diagonal matrix elements of s and /" operators is less spectacular. This is mainly due to the absence of quantum correlations in the ground stale and reflects strong sensitivity of the off-diagonr-1 matrix elements to details of the wavefunction. For large-TV, these correlations are the familiar 2p-2h RPA correlations which do not influence the excitation spectrum or diagonal matrix elements but may have a strong effect upon the off-diagonal matrix elements for operators which connect to the ground state. Generally, as long as one is able to localize stable periodic orbits in the parametric space, the agreenr-nt between results of SU(3) model and its mean field limit extended to include quantum con utations due to parity projection is very good. In conclusion, the TDVP supplemented with the geometrical quantization condition, ap- pears suitable for reproducing various quantum mechanical quantities. This method seems also to be more efficient than the semiclassical method, particularly for the chaotic systems, in which the latter method requires many classical trajectories to build the wavefunction. This is due to the fact that in variational approach the majority of quantum mechanical effects is incor- porated abeady from the beginning while the semiclassical methods aim at reconstructing the wavefunction from purely classical trajectories. 22 <2IMI2> -f KilillM. Fig, 1: Th^ matrix elements for operators: H, a = Nn — ^oo tuid i — 7V22 + N\i — 2NQO as calculated ex&ctly in SU(3) (full dots) and in the projected man- ifolds {^.)..|.}, {^r }• for the first two excited states 20 10 60 N 20 u) (0 H |1), |2> and the ground state |0) at x = 10- References: [1] S. Drożdż et at., Ann. Phys. (N.Y.) 171 (1986) 108 [2] E. Caitrier et al., Nuci. Phys. A506 (1990) 262 [3] R. D. Williams and S. E. Koonin, Nuci. Phys. A391 (1982) 72 [4] E. Caurier et al., Acta Phys. Polonica 22B (1991) 389 Classical cluster model for heavy ion reactions K.Mohring1, T.Srokowski and D.H.E.Gross1 ^lahn-Meitner Institut fur Kernphysik, 1000 Berlin 39, FRG. The many-body structure of mcleus must be taken into account explicitly when we investi- gate heavy-ion reactions with bombarding energies comparable to the nucleonic Fermi energy. For lower energies, they are known to proceed as binary reactions, the observed ejectiles are understood as resulting from a friction process. Rising the bombarding energy, a probability for incomplete fusion becomes substantial and nuclei can break up during the collision process. At the same time, at higher bombarding energy still strongly dissipative processes are possible. We have considered the reaction 20Ne + lorAu, in the energy range 150 - 400 MeV where those processes have clear experimental evidence. The model[l] consists of a specific combi- nation of microscopic and phenomenological concepts. The projectile has been assumed as an alpha-cluster (15 degrees of freedom treated explicitly) with alpha particles interacting via two body potential, taken from TDHF calculations[2]. In addition, we have introduced a random force between alpha particles. The reason was to cure discrepancies between classical and quan- tum pictures of a — a scattering. The quantum scattering exhibits considerable large-angle cross section, corresponding to very low partial waves. In order to simulate that effect, we randomly 23 choose a direction of relative momentum of two a- particles, as soon as they come closer than a given distant. To get a proper representation for 20Ne, we have sampled the phase space uniformly keeping the total momentum of the isolated nucleus zero and the total energy fixed at the experimental value. The resulting position and momentum distributions have been prop- erly reproduced. Interaction between the target and any alpha particle from the projectile is phcnomenolojjical because the internal degrees of freedom of the target aTe not taken into ac- count explicitly. It consists of the folding potential and the surface friction force of Gross and Kalinowski[3j. Trajectories have been calculated for a given bombarding energy and impact parameter. The final outcome has been obtained by averaging over internal configurations of the projectile. During the time evolution the projectile can break, some a-particlcs being transferred to the target. In the exit channel one can get a variety of configurations: a few fragments (or-cluater nuclei or single a-particles and a heavy fragment), a binary system or the compound nucleus (the complete fusion). Of course, any transfer of a single nucleon is impossible in our model since we neglect nucleonic degrees of freedom. Results have been compared with experimental data, especially rich for thi3 system. Agree- ment appears Co be good, both for inclusive (complete fusion) and differential cross sections. The deep-inelastic branch in the double-diflerential cross section for various ejectiles has been qualitatively reproduced. An especially crucial test of the model is a comparison of its predic- tions with measured coincidences of projectile-like iragments with a-particles as well as between two a-particles (Fig.l). Despite all simplifications, the agreement is quite good. lit1 l I , ^""^ . " T c •a 10* •a 102 101 Fig.l. Angal&r distribution [or a-particles in co- ino • I'JO (id 0 60 i;:<) inn incidence with Another a, observed &t O^ EL =400 Q-, MeV. References: [1]. K.Mohring, T.Srokowski and D.H.B.Groas, Nuci. Phys. A533, (1991) 333. [2]. D.Provoost, F.Grummer, K.Goeke and P.G.Reinhard, Nuci. Phys. A431, (1984) 139. [3]. D.H.E.Gross and H.Kalinowski, Pliys. Rep. 45, (1978) 175. 24 Measurements of the bremsstrahlung photons in collisions of 129Xe-}-197Au at 44 MeV/u H. Dąbrowski, B. Fornal and L. Freindl Collaboration TAPS : R.Merrouch, H.Delagrange,F.Lefàvre,W.Mittig,R.Ostendorf, Y.Schutz (GANIL Caen), F.D.Berg W.Kuehxi,V.Metag,R.Novotny, M.Pfeifer,(Univ. Giessen), A.L.Boonstra,H.Lohner,L.B.Venena, H.W.Wilshut (KVI Groeningen), W.Henning, R..Holtzman, R.S.Mayer, R.Simon (GSI Darmstadt), F', Lautridou, J. Québert (CENBG, Bordeaux.) D.Ardouin, B.Erazmus, D.Lebrun, L.Sezac (LPN Nantes), F.BnUester,E.Casal,J.Diaz,J.L.Ferrero, M.Marques,G.Martinez,(IFI C Valencia), H.Nifenecker(ISN Grenoble) Z.Sujkowski (IEN Świerk), T.Matulewicz (Univ.Warszawa) Multidetector TAPS (1] consisting of 247 BaF% crystals and covering about 27% of total .solid angle was used to measure the photons and to study their possible interference effects in order to determine the life-time characteristics of the emission source. As was already presented [?.\ the hard photons of the energy greater than 30 MeV produced in heavy ion collisions for beam energy greater than 20 MeV/« are coming from the source moving in the beam direction and velocity of the CM nucleon-nucleon system. The bremsstrahlung spectra are exponentially decreasing with energy (fig.l), they are peaked at. the forward laboratory angles (fig. 2) [7] the cross-section increases with the beam energy find the mass of the system. The angular distribution in the nucleon-nucleon CM system is isotropic with a dipolar type contribution. The above experimental'observations lead to the conclusion that the photons are produced in individual nucleon-nucleon collisions from target and projectile nuclei- mos'ly of the p + n,n + p type. Dipole type contributif n results from the deacceleration of the projectile nucléons, the iüutrcipic part comes from their acceleration after scattering on the target nucléons. The macroscopic results, using the solutions of the Boltzman - Uhlenbeck - Uehling transport «'(juiition. show that the principal contribution to the hard photon spectra comes from the first proton-neutron and neutron-proton collisions [3]. Contributions from the other sources lik« coherent many nucléons production (4], coherent production in cascading processes [5] or statistical high energy photon emission [6] are negligible. Fig.l shows the laboratory energy photons spectra produced in l29Xe -j-197 Au collisions at 44 MeV/u of the GANIL (Caen, France) beam'. For E^j lower than 25 MeV the photon spectra, the principal contribution comes from the thermal photon deexcitation of the hot fragments produced for diiferent impact parameters. For the energy Ef > 25 MeV the principal contribution to the 7 energy spectra results from the bremsstrahlung n — p, p - n individual collisions. The exponential'slope Eo is equal 1.0 11.5-Ï-0.3 MeV. Between energy E7 = 12-20 MeV one observes the contribution from the dipole giant resonance. Fig.2 shows the laboratory angular distribution of photons integrated above the energy threshold Ey -- 30MeV. The solid line represents the sum of isotrope and dipolar contributions in the nucléon-nucléon CM frame. In this experiment we do not observe the quadrupole contri- bution to angular distribution of photons, which is characteristic for the coherent bremsstrahlung process for projectile and target nuclei acting as a whole. 25 Xe + ' Au 44 MeV/nucIeon ung pholoa M, S t - I t.t ±0.1 MeV Fig J. The Jaboratoiy energy photons spectra, pro- duced in U9Xe +19T Au collisions at 44 MeV/u of the GANIL (Caen, France) beam. '"Xe + '•'Au =,' r MeV/nucleon w a E, > 30 MeV 3,300 O 250 JOO - ^1 1J0 • 100 Fig 2. The laboratory ajtgular distribution of pho- 70 SO 90 100 110 120 IJO l<0 ISO tons integrated above the energy By = 30MeV for the same reaction. References [1] V.Metag Lecture at the International School of Physics, Varenna, Italy 1989 [2] H.Nifenecker, J.A.Pinston Prog.Part.Phys.23 (1989) 271 [3] W.Cassing, V.Metag, U.Mosel and K.Niita Phys.Rep. 188 (1990) 363 [4] D.Vasok, B.Mueller, W.Greiner J.Phys. (711(1985)1309 [5] H.Nifenecker, J.P.Boudart Nucl. Phys.A442(1985) 478 [6] M.Prakash, P.Braun-Munzinger, J.Stachel Phys. Rev. 033(1986)937 [7] R.Merrouch et al. TAPS collaboration, Nouvelleg du GANIL,No38,Avril iy91,p4 26 Interference of hard photons emitted in collisions between heavy ions. H. Dąbrowski, B. Fornal and L. Freindl Collaboration TAPS : R.Merrouch, H.Delagrange,F.Lefevre,W.Mittig,R.Ostendorf, Y.Schutz (GANIL Caen), F.D.Berg W.Kuehn,V.Metag,R.Novotny, M.Pfeifer,(Univ. Giessen), A.L.Boonstra,H.Lohner,L.B.Venena, H.W.WUshut (KVl Groeningen), W.Henning, R.Holtzman, R.S.Mayer, R.Simon (GSI Darmstadt), D.Ardouin, B.Erazmus, D.Lebrun, L.Sezac (LPN Nantes), P. Lautridou, J. Quebert (CENBG, Bordeaux) F.Balle.ster,E.Casal,J.Diaz,J.L.Ferrero, M.Mar Hard photons produced in collisions between beavy ions originate mostly from nucleon- nucleon interactions, in which the initial relative mommtum superposes on the internal Fermi momentum of the projectile ano target nuclei. The photon counting rate is an increasing function of the number of the p - n pairs and the accessible center of mass energy. Those high energy ganunas(E'7 > 25 MeV) are created in the initial stage of the reaction, so the life time of the hard photon source ;s much shorter than the total reaction time [1]. The above observations suggest the use of the Handbury-Brown and Tv.iss [2] intensity interferometry method as suitable for the purpose of estimating the space - 'emporal evolution of the emitting hard photons source. The study of the quantum mechanical statistics of the boson source is also very interesting . The photons sonde seems efficient because the distortions from the interactions with nuclear environment are weak. Therefore one can construct the experimental correlation function : c12(kuk2) = ^„A^ti.tjpifM^^) (i) wliTe Jfci, hi are the four vectors of energy and momentum of particles 1 and 2 respectively, N\i is the coincidence spectrum, N\yN2 «ire the single photon spectra, Knorrn is the normalization factor. The space-temporal evolution of the emitting source can be extracted from the comparison the experimental and the theoretical model dependent correlation functions, for example by using the Koonin or Kopylow methods [3], The experiment mads in Ganil ( Caen, France) used the TAPS BaF2 multidetector [4] measuring the simple and coincidence spectra of hard photons (Ej > 25 MeV ) for which the experimental correlation function was calculated. Photons were produced in the reaction 129Xe +197 Au at energy of the beam 44 MeV/u. The resulting experimental correlation function for hard photons is presented in fig.l where value q is defined as : For values q lower than 30 MeV/c the increase of the correlation function C\2 with decreasing q is clearly visible. In the vicinity of q « 0 MeV/c correlation function C\i w 1.9. The above indicates interference effects for the incoherently emitting boson source [5]. 27 Er > 25 MeV 1.97 ± .2.3 Fig. 1. Two htxrd photon correlation function, for photons measured in the reaction noA'e f-107 An ai 25 SO 75 100 12S ISO 17fl 200 q, (M.v/c) 44MeV/u. References: [1] K.Niita, W.Casing, U.Mosel, Nucl.Phys.A504(1989)391 [2] R. Handbury-Brown,The Intensity Interferometry, ed.Taylor and Francis Ltd, London 1974. [3] G.LKopylow, Phys. Lett. 505(1974)472, S.Koonin, Phys. Lett. 705(1977)43 [4] V.Metag, Lecture course given at the International School of Physics, Varenna, Italy, 1989. [5] Y.Schutz and TAPS Collaboration, submitted for publication in Nucl. Phys. A. Search for lifetime effects of an evaporative source using two-proton correlations. H. Dabi-owski In collaboration with: D.Goujdaini,F.Guilbault,C.Lebriui,D.Ar Measurements of the two-particle correlation function between light particles emitted in the heavy-ion collisions can be used to provide information about time- spatial evolution of the emitting source [1]. Difficulties arise when final state interactions influence the primary particle emission, so the final quantum mechanical statistics and interference effects observed fire different from the initial ones. Many analyses have been carried out assuming a fixed Lieiime of the source leading to the overestimated spatial source dimensions [2]. Also the spatial expansion effect corresponding to smaller freeze-out densities for complex fragment; emission causes the larger effective sizes of the source [1]. Pratt, et al. [3] have claimed for the proton-proton pairs the existence of the directional effects associated with the source elongated in the direction of the long lived emission. This appearance is caused by quantum statistical effects between two correlated fermions producing a weaker negative interference along a direction where the emission time difference will result in the larger separation of the proton pair. The experimental proton emission was analyzed at backward angles for the *°Ar 4-nai Ag reaction at 44 MeV/u beam energy using GANIL (Ca*n) facility. The 24 Csi detectors measured the proton-proton coincidences placed in the backward hemisphere between 90 and 160 deg 28 [4]. The two body correlation function defined as the ratio of the coincidence spectra to the tioijcorrelated single spectra at a given protons momenta R(K, q) = JVnorm * N(puPi)/(N(pl) * N(P2)) ' (3) a (where K — Pi+pji 1 — Pi ~P2iPi andp2? re the proton pair momenta, Nnorm is a normalization factor) is present in fig, 1. PaTt (a) of fig.l presents the correlation function for the total average momentum selection K — 600 MeV/c for the relative momentum parallel (3? =0 deg) and perpendicular (\P =90 deg) to the total momentum. Part (b) of fig.l presents similar results for the average total momentum K= 350 MeV/c. The angular averaging range was 30 deg for polar angle, and 50 MeV/c for the absolute value of K. Within statistical error the correlation function for q lower than 30 MeV/c shows the directional effects about 15% and does not present the total momentum dependence [4]. The solid and dashed lines are predictions of evaporation from the hot liquid drop model taking into account the relative motion of the system and antisymmetrisation for the proton vawc function ( Friedman and Lynch [5] ). The theoretical angular dependence is weak and fits the experimental data points for the higher momentum selection better than lower ones. 40 '<•< Af• *g - 1.9 1, 44 M«V/m Ę 1.0 • 1 tt-eoa M«v/e o.s I JO <0 GO qlMaV'cl 44 MlV/nucldOlI K-3iOM«V/e -•- References. [1]. J.Pochodzalla et al. Phys. ReV. C35(1987) 1695 [2]. A.Kyanowski et al. Phys. Lett. D181 (1986)43 , H.GustafFsson et al..Phyo. Rev. Lett. 53(1984)544 [3]. S.Pratt et al. Phys. Rev. C36( 1987)2390 [4]. D.Goujdami et al, Zh. Phys. A339(1991)293 [5). W.A.Friedman,W.G.Lynch, Phys. Rev. C28(1983)16 29 Search for an enhanced production of low energy pions in proton induced reactions on Cu and C targets at beam energy between 300 to 400 MeV. H. Dąbrowski In collaboration with: J.JulienjM.BolorejJ.GosseljJ.M.IIisleur.A.MougeotJJ.Saghai, G.Sanouillet (DPN, CEN Sacla;, France) D.Ardouin.B.ErajuuiSjC.Lebrun (LPN, Universite de Nantes) V.Bclliiii,G.Pappa}nrdo,T..Sperduto (INFN Catania) C.Cerulti.S.Lcray, C.Ngo (LNS, SATURNE, Saclay) D.Lcbrun,P. dc. Sainfignon (ISN, Grenoble) L.Bimbot (IPN Orsay) T.Johansson (SWBDBERG Lab. Uppsala) K.Kiliun (IKP, Jiilich) Paper of Krasnow el. al. [1] presents the invariant cross-sections of the positively charged 63 + pious for the reaction p f Cu = X + TT . Energy of beam Tp has been varied in 25 to 50 MeV steps between 250 MeV to 600 MeV. The pions spectra were analyzed in the energy region of 30 to 155 MeV. For this reaction the exponential slope parameter Eo of the invariant cross-section monotonicaUy increases with the beam energy except for the energy of protons equal to 350 MeV, where Ea is lower than at preceding 7), value of 325 MeV. In order to explain this unexpected anomaly another experiment was carried out for the samn target using the proton beam with 10 MeV steps of the SATURNE (Saclay) accelerator [2]. To avoid systematic errors the ratios of the low energy to high energy pions invariant cross-sections were analyzed for !he emission angle around 90 deg. The anonial local increase of this ratio was also found at proton beam energy Tp — 3E0MeF. To improve the experimental resolution of the observed phenomena we have repeated the experiment for 2 MeV beam step around Tp = 350 MeV, and with 10 MeV step for lower and higher beam energies ( fig. 1) [3]. The R value previously defined for the reactions p+63Cu — X -f 7r+ and p+12 C = X + ir+ versus positive pions energy is presented in fig. 1. The 5 MeV wide structure is visible for the copper target, no enhancement is observed for this beam energy for carbon target, where a higher value of R was found for beam energy of 330 MeV. The magnitude of this enhancement in both cases is about 5%. A similar search fru L'lai, anomaly was made for no meson channel using copper target. (3). The results axa presented in fig. 2. Because of poor energetical and angular resolution of the % Cerenkow detector the existence of this anomaly cannot be observed [3]. One of the possible explanation of this production rate is the creation and decay of the dibarion resonance p + p —3 Fs~ > p + n f Jr+, however the Fermi motion and any structure for the nucleon - nucleon system should be washed out for the nuckon- nucleus system. Another possibility is a resonant decay of the A A resonance into pions channel. The p - wave A resonance decays into vr channel at energies around Tjr+ « 30MeV wil.h the width of =s 7 MeV [4]. 30 P'CU—n'»x «• a _ FWI1M"SM«V 1.0 o.ta ł OJM 0.6 i*i ji« 31) n.fl N ''2"+S0M.VI n 4 n M_«(7S+100M«VI 0.4 i i • i • i. ta • f • ptc —n**x b) - 0.8 Fig. 1. The ratio R of low to high energy JT+ invariant cross-section versus kinetic energy proton o.s 4 •1 be&m. Part a) corresponds to carbon target, part * V75+100M.V, ł b) corresponds to copper ttuget. The structure at 0.4 320 3-10 300 390 400 420 Tt « 350AfcV is visible for copper target and at Tp IM»VJ Around 330 MeV for carbon target. 0% 0" } 1 ł 1.0 11 ł ł 1.7 • 60V 15 O--1S0* w. t mi 1.3 p .0, X" a ł • IS 1.1 Ci . i ł «*• 0* ł Fig. 2. The R ratio for ir apectra for copper tor- • M o get.Parta a), b) and c) corresponds to three angular ł 320 340 360 380 cats. No visible structure atound Tp in 350MeV is Tp (M«V) present. References. [1]. V.A.Kra9now et al. Phys. Lett. 108B(1982)ll [2]. J-Julien et al. Phys. Lett. 142B(1984)340 [3]. J.Julien et al. accepted for publication in Zh. Phys. A [4]. V.A.Kurepin et al. Lett. J. Sov. Phys.49(lŚ89)603 31 Temperature measuremexits of the reaction zone in the heavy ion induced reactions H. Dąbrowski In collaboration with: D.Ardouin,P.Eudes,D.Goujdatni,F.Guilbiiult,C.Lebrun,B.Rcmaud, F.Sebille (LPN,Umv.Nant(!s,France) P.Lautridou, J.Quebert (CEA Gradignan, France) A.Peglmire (GANIL, Caen, France) The question of the equilibration of degrees of freedom in heavy ion. induced reactions at intermediate energies of the beam is crucial for understanding nuclear many body dynamics. Experimental observations of light particles emission can give inforiŁ.iUon about degree of the equilibration in the reaction zone. However (,he contribution to the light particle spectra observed conies not only from the equilibrated source, at intermediate beam energies a very important contribution in the observed spectra comes from the preequilibrium processes. These processes dominate at the forward angular hemisphere, whereas for the backward angular region an emission from equilibrated source is dominant. From the above observations we have deduced the emission temperature by measuring the population ratio of the excited states of light clusters emitted at backward angles between 90 and 150 deg for the reaction 4iAr +108 Ag at the 44 MeV/w energy of the beam. We measured 6 the emission of the alphas ( ground state and Eexc = 20.1 Mev, Jv — 0+ excited state) and Li( Eexc=2.187 MeV, JK = 3+ and Eexc =4.31 MeV, Jv - 2+ excited states). The numbers of the particles for a given excited state can be extracted using thu correlation function method [1] and normalizing for a given detection geometry taking into account calculations of Monte Carlo type. 3.0 i 44 MgV/u 3.5 T-J.J M«V i T-2.9 MiV 31.1 W«V 3} | MaV 1.0 1 1 Itl 0.5 121/ Fig. 1 Proion-tiiton correlation function. Excitation AllK . —• 1 ..i i energies in the n]pha particle are indicated. The solid f"'"'" lines show the background substractión limits used for the estimation of the. te/nperature uncertainly. Fig.l presents the correlation function for proton-triton pairs. At the relative momentum 32 alpha emission and Temp = 2.9±0.7 MeV for the aLi emission [2] , Those values are lower than the values of the temperatures between 4.5 and 5 MeV usually observed in similar measurements i\t forward angles [3]. The temperature value between 2 and 3 MeV for backward emission, is j'.lao lower than the slope parameter of the single particle spectra. This difference has received interpretation [4] involving dynamics of the collision. Schematically, the slope parameter reflects the average contribution of the de-excitation cascade and thus the dynamics of the collision, while the "chemical" temperature received from the population ratio is established at the break time of the system when fragments are formed. 1 44 MvVfu 1 T-J.ł M.V T-J.J M.V T-J.J M.V • « 4.1 M*V 11.8} M.V Fig. 2 Alpha-dcuteion correlation function. The m- 20 41 BO HO log 120 yll.V/cl dications are the same as in %. 1. References. (1). J.Poehodzalla et al,, Phys. ReV. C40(1939)2918 [2]. II.Dabrowski,D.Goujdami,F.Guilbaiilt,C.Lebrun,D.Ardouin, P.Lautridou Ph. Lett. 2475(1990)223 [3]. Z.Chen et al., Nucl. Phys. A473(1987)564 J.Pochodzalla et al. Fhys. Rev. C35(1987)1G95 [4]. D.Bool ct al., Phys. Rev. CG2(1989)737 Pion production in heavy ion reactions using 16O beam at energy 60 MeV/u. H. Dąbrowski In collaboration with : G. Perrin, G. Duhamel-Chretien, D. Lebrun, P.de Saintignon (ISN, Grenoble), C. Le Brim, J.F. Lacolley, 11. Bougault, D. Durand, A. Genoux-Lubain, M. Louvel (LPC Caen) The production of pions in collisions between heavy ions at subthreshold energies in last ten years has been intensively studied [1]. At energies of the beam below 1.00 MeV/u the pions cross-sections largely exceed the expected value for single nucleon-nucleon collision models including boost from internal Fermi motion [l]. This high probability of pious production can be attributed with the collective phenomenon of pious production mechanism, for which the reaction tlixeshold lowers with the mass of interacting clusters.Various models have been proposed to explain the observed inclusive pions angle, energy distributions and their variation with the hcam energy and atomic masses of the target and projectile. One type of models proposes 33 a statistical mechanism of (lie production from the hot zone [2], another suggests collectivity in the production phenomena [?,]. Recent investigations (4] reproduce the experimental pions cross-sections using a single mcleon-uucleon production mechanism and taking into account in- medium effects in the participant, nuclear zone. The important problem concerning the study of the sublhreahold pions production is their reabsorplion and rescattering in nuclear hot medium [5]. These final state* interactions conceal the initial mechanism of the production. As already was shown, the estimation of pions absorption is between 70% to 90% of the initial pion flux, depending on the projectile and target atomic masses, their energy and mean free path [5]. These effects elucidate qualitatively the observed backward - forward asymmetry in angular distributions of neutral pions [1]. The above remarks suggest that the understanding of those phenomena is still incomplete. One of the methods for understanding the pions production mechanism is to study the ratios of cross-sections for opposite charged pions. Since the distortions of the negative and positive pions trajectories and phase space by charged fragment participants are different, the analysis of those ratios for different combinations of projectile- target mass provide information on the characteristics of the ptr a emitting source [6]. In the experiment made in GANIL (Caen) [7] one measured charged pions for the reaction ia of O uearn at energies 65 and 93 MeV/ti on targets LitC,AltAg and Au. The ratios R of the cross-section integrated between 0 deg and 15 deg for two charged pions is presented in fig, 1. The R is plotted versus pions momentum in the projectile frame at rest. At the momentum p in the vicinity of p sa 0 MeV/u one observes the Coulomb distortion effects associated with the focusing and de-focusing phenomenon for the pion of the opposite charges in the field of the projectile like fragments. The ratios R for 60 and 93 MeV/u energy beams are similar. Globally the R increases with tht target mass, except for the hi target corresponding to the inverse kinematics, however in the region of the low momentum the two data sets are almost overlap. A small broadening of R at tho lower beam ancrgy reflects the wider momentum tfiapersion of fragments for that reaction. In the case of heavier targets this effect is less visible. K IS II Al Fig. 1. The R xatio of the cioss-sections + •It -10 0 10 JO JO l» 5« (r(ir~)/cr(-7r ) integrated over angles between 0 and PK ( MeV / c ) 35 deg veisus momentum p in projectile test frame. 34 References. [1]. Reviev of papers presented in : P. Braun-Muniinger, J. Stachel, Ann. Rev. Nucl. Part. Sci., 37,(1987)97, and W.Benenson, Nucl. Phys., A495(1989)21c [21 J.Aichelin.G.F.Bertsch, Phys. Lett. 13813(1984)350 and J.W.Nordbury et al. Phyu. ReV. Lett. 55(1985)681 [3]. D.Vasak et al. Nucl.Phys., A428(1984)291c and R.Shyam, J.Knoll, Nucl. Phys., A426(1984)606 [4]. W.Cassing et al. Z. Phys., A329(1988)487 and references therein [5j. H.Dabrowski.XXVJ Int.Wintcr Meeting of Nucl. Phys. Bormio(l988)269 [6]. D.Lebrun et al. Phys.Lett., D223(1989)139 [7]. G.Perrin et al. Submitted for publication in Z.Phys. Investigations of the ix and proton induced reactions Li Z. Lewandowski and R. Wagner1 1Institut fur Physik dor Universitat Basel, Basel, Switzerland Slow TT~ are absorbed mainly by a correlated pair of nucleons (the so called qxiasi deuteron model). After converting a proton into a neutron, the rest mass of the pion is shared between the two nucleons involved, taking their Fermi energy into account. Each of these nucleons can either escape or initialize a cascade leading to the emission of nucleons or complex particles, respectively. Bombarding the nucleus by fast protons can also produce a cascade, this time having a fixed initial energy. E.Gadioli [1] discussed the similarity of these cascade processes. We investigated a and 3He particles in the exit channels using our data for 72MeV proton projectiles on light, medium and heavy nuclei and compared them with results published in the thesis by U.J.Sennhauser[2] on the emission of particles produced by slow negative pion absorption on 12C, E0Co, and 107Au nuclei at PSI. Comparing over a broad energy range the yields of particles in the T~ and proton induced reactions we have demonstrated [3] a close similarity of these two reactions and that in the pion induced emission, on the average, one of the two primary nucleon is active. Analyzing the proton, deuteron, and triton exit channels we found quite a different situation. E.g., tritons and3 He, both consisting of three nucleons, have approximately the same yields in the proton induced reactions whereas the pion induced yields of the triton has a much higher value than those for 3He. E.Gadioli [4] discussed our method of analysis pointing out that there is no unique way of performing such a comparison, due to the initial interaction of the primary nucleons in the cascade. As a consequence, in his opinion, the analysis should be performed not in the channel but rather in the laboratory energy system. Therefore, we performed the analysis in both systems for 12C, the lightest nucleus considered, obtaining similar results. «=the ratio of the pion-to-proton induced yields, is for protons 0.42-0.6, for deuterons 1.38-1.4, and for tritons 4.3-3.4, respectively. We extended the analysis of the proton, deuteron, and 3He yields using for the proton-induced reaction the data for P« by Bertrand at al.[5j comparing them with pion-induced data for Co. This analysis gave a rather similar result, i.e. we obtained for p, d, and t K valuei of 0.59, 2.2, and 6.2, respectively. The most striking case is the formation of tritons. One can explain the observed discrepancy by the different mechanisms of formation of the tritons and 3He in the negative pion absorption in the nuclei. The differences between the pion and proton induced reactions for p, d, and t yields, in our opinion, cannot be explained by pion absorption on the alpha chif ters in the nuclei [6]. Study of the it~ and proton induced reactions are in progress. 35 References: [1] E. Gadioli, Nukleonika 26 (1981) 945 [2] U. J. Sennhatiser, Thesis ETH No. 6931 (1981), unpublished [3] R. Wagner, Z. Lewandowsld, and H. H. Mueller, Nuci. Phyu. A459 (1986) 606 [4] E. Gadioh" et al. Z. Phys. A327 (1987) 81 [5] F. E. Bertrand et al. Phys. Rev. C8 (1973) 1045 [6] E. Gadioli et al. Phys. Rev. C36 (1987) 741 Study of the 28Si(a,J0O)I6O reaction I. Skwirczyriska, L. Freindl, W. Karcz, S. Kliczewski, M. Madeja, J. Szrnider, R. Wolski and A. Budzanowskl The anomalies found in elastic and inelastic scattering of a-particles, in some reaction chan- nels and in the fusion cross section are particularly distinct for the 4n target nuclei. The aim of our work is to study resonances at high energy excitation of compound nucleus 32S nnd to determine their quantum characteristics. The 28Si(a,16O)10O reaction have 10 - been studied at EQ=24.9 MeV. In order to achieve good energy resolution a thin self- supporting target of thickness 90 /tg/cm Si was used. Detection and identification of the reaction products were achieved by coincidence measurements with E - AE en telescope and large solid angle semicon- \ ductor detector positioned at the angle siutalbe for detection of the recoiled nu- O cleus. The AE detector was ionisation E chamber (Ar+10%CH4 ) and E was 20/u 28 16 16 thick Si detector. A total solid angle was Si(alpha, 0) 0 Ecm - 21.79 WeV 2.09xl0~3 sr. Additionally, time between coincidence impulse in the telescope and in recoil-nucleus detector was measured. Energy signals from three detectors and 10 time were stored event by event to be sub- 0.00 40.00 80.00 120.00 sequently analysed off-line. Angular dis- theta CM tribution were measured for angles from 28 up to 64 degrees in the lab system In steps of 4 degrees (Fig.l.). 36 Influence of the shell effects on cluster emission A.G. Artukh1, G.F. Griflnev1, M. Gruszecki, S. Kltczewski, M. Macieja, V. Mikhecv1, J. Szmider, I.N. Tarantin1 and R. Wolski 'Joint Institute of Nuclear Research, Duhna. The r'8Ni|-BeNi--tSn f-'- Focal plane detector for the projectile fragment separator COMBAS A.G. Artul.hi,:^.A._Bugadj>y\G.]^G^^ S. Kliczcwski, M. Madeja, Y_JA. Nikitin1., A.A. OmeJyanenkoVP. Povinec2, M. Semanf, A.A. Sanen^il^S^ltl-.^p^^t^^midc^Yu^TtAcccYl a«d A.G. Zielinskt4. 'Joint Institute of Nuclear Research, Dubna. 2Comenius University, Bratislava. 3Institute of Experimental Physics, Kosice. 4Institute for Nuclear Research, Kiev. In nuclear reactions induced by energetic heavy ions many elements are produced in each event. The studies of these reactions, especially those with ultra-small yields, need a device which would provide identification and a full kinematic analysis of multi-body events. The time projection chamber (TPC) allows three dimensional reconstruction of multi-track events and identification of charged particles by ionization sampling. The TPC detector is planned to be used at the Laboratory of Nuclear Reactions, Dubna, as a focal plane detector for the magnetic channel COMBAS, designed for the separation and formation of secondary radioactive beams. The TPC with sensitive volume: x=1600, y=800 and z—350 mm and 80 layers for the dE/dx measurements has been built for this aim. A preliminary test of the TPC has shown that the spatial resolution for the vertical (z) coordinate was better than 0.5 mm and for the horizontal (y) coordinate was better than 1.5 mm. The estimated charge resolution, z/Az, for He, Mg and Fe elements was of the order of 100. Thus, this unique properties of the TPC can be used for investigation of multi-body processes in nucleus-nucleus collisions and multi-particle decays of exotic unstable nuclei. 37 Method of the excitation function measurements in a wide energy interval K.P. Attemov1, O.P. Uielanin', A.L. Wieloschkin8, R. Wolski, M.S. Golovkov1, W.Z. Goldberg1, M. Madeja, W.W. Pwibkralov1,I.N. Sierikov1, W.A. Timofeev1, W.N. Schadrm2 and J. Szmider. 'Kurchatov Institute of Atomic Energy, Moscow. 2State University, Tomsk. The method is based on range differences between light and heavy ions. Using reverse kinematic, where lighter recoil nuclei are detected heavier projectiles, traversing through a target loss their energy along trajectory until they are stopped. In this way the energy of bombarding ions smoothly decreases from the maximum value, Emai , at the beginning of target to zero. Thus, the energy spectrum of recoil is strictly related to the excitation function for energy interval (Emax-Emjn), where E,njn is the minimum energy of projectiles at wlu'ch recoil nuclei still, reach the detector. The method was tested using the *He-f12C reaction. The results are shown in Fig. 1 and it is evident complete correspondence between spectrum of recoil a-particles rnd the excitation function [1]. Using this method, angular distributions and excitation function for the elastic scattering of alj.has on 16N were measured. The comparison of the part of our results [2] with the earlier published data [3] is shown in Fig. 2. o e *ieo- 3 10 u 12 13 E*, MeV- cn I 3 10 11 12 13 E,MeV. 6 9 10 U 12 E , MeV Fig. 1 Fig. 2 References: [lj T.P. Marvin and P.P. Singh, Nuci. Phys. A180 (1972) 282 [2] Jad. Fiz. 52 (1990) 634 [3J H. Smotrich et al., Phys. Rev. 122 (1961) 232 The properties ol r°Si resonances at the 31.5 MeV and 33.2 MeV excitation energies via the 24Mg(or,nC)16O and 24Mg(a.a)24Mg reactions R. Wolski, I. Skwirczyńska, A. Budzanowski, L. Prcindl, J. Jakiel, W. Karcz and J. Sziuider We studied the 28Si compound system by means of (a,13C) reaction and (a, a) elastic scat- tering in the a-particle energy range from 24.9 to 27.76 MoV [1]. The data revealed the exis- 38 tence of ft narrow resonance at 33.2 MeV exc. energy (27.1 MeV lab.), not reported earlier, and a structure at 31.5 meV (25.1 MeV lab.). The latter could be identified as known 14.7 MeV CM energy resonance in thel2 C+lflO reaction [Ą. The resonance parameters for («, a) channel were estimated by phase shift analysis using optical model to generate background amplitudes. The partial width for t2C }10 0 channel was extracted from the excess over the energy independent component of the total (a,1JC) reaction cross-section at the resonance energies. The reduced widths 0? for each channel were obtained calculating appropriate penetrabilities at the radii R that of the effective potential barriers. E„(MeV) charutel Vi/r T(keV) r.-(keV) R(fra) ©?(%) 25.1 a+Mg 0.1G 280 44.8 6.7 9.2 10"3 9~ «c+"o 0.026 280 7.3 7.5 5.4 10~3 27.1 a+Mg 0.07 370 26.0 6.5 8.3 10~3 11- 12C+16O 0.053 370 20.0 7.3 1.7 10~2 References: [1] I. Skwlrczyńska et al., Nud. Phys. A452 (1986) 432; R. Wolski et al., INP Report 1392/PL (1988) [2] A.D. Fravley et al., Phys. Rev. Lett. 44 (1982) 1377 Charged pion production in proton collisions with C, Cu, and Pb nuclei in the energy range 320-380 MeV Yu. Akimov, M.I. Gostin, I.I. Haysak, S.I. Merzlyakov, A.G. Molokanov, K.O. Ogsmesyan, E.A. Pasyuk, S.Yu. Porokhovoy and R. Wolski. The work was devoted to check an effect which was observed earlier [1] in spectrum of pions produced al 350 MeV proton bombardment the natural Cu target. The authors reported an enhancement of low energy pions when the proton energy is close to 350 MeV. In the present experiment the yield of ch.vrge particles emitted at 90 deg. Lab. was measured as a function of proton energy in the range 320-380 MeV. The natural targets of C, Cu, Ga, Pb were investigated. The monochromatic protons were obtained from J1NR phazotron 800 MeV beam passing graphit absorber and magnetic selector. Average energy step was 5 MeV. Incident proton energy was measured by rime of flight method. Accuracy is estimated to be better then I MeV, energy width was 2-3 MeV. Detected products were identified by time of flight-full energy scintillation spectrometer. No anomaly in pion spectrum for C and Pb target was observed. In the case of Cu and Ga elements at 350-355 MeV proton energy some irregularities can be seen in the pion spectra normalized to the proton's spectra. Statistical confidence of these findings is inconclusive regarding the effect in question. References: [1] V.A. Krasnov et al., Phys. Lett. 108B(1982)ll J. Julien et al., Phys. Lett. 142B(1984)340 39 Muon transfer rates in hydrogen isotope niuonic atom collisions A. Adamczak, C. Chiccoli, V.I. Korobov, V.S. Melezhik, P. Pasini, L.I. Ponomarcv and J. Woźniak submitted to Phya. Lett. B During the last two decades the physics of niuon catalysis has been extensively studied by theory and experiment [1,2]. To improve this knowledge one has to describe the kinetics of muon catalyzed fusion. One important parameter that appears in the kinetics is the muon transfer rate in niuonic atomic collisions. This paper presents he multi-level adiabaiir calculations of the muon transfer rates for all the processes involving hydrogen isotope muonic atoms in the ground state: d/i + t, 4-1 -t t i + d 4 + t -|- p, ( The calculations are performed in the adiabatic representation of the Coulomb three-body prob- lem [3]. In experiments the muoruc transfer reactions take place in collisions of muonic atoms with hydrogen Ttolecules. To compare the experimental data with the calculated rates it is necessary to estimate electron screening corrections. The influence of molecular binding on the considered rates is negligible since the energy released during the mubn exchange is much greater than the energy of the of rrolecular binding. The method of calculation of these corrections ha? been presented in R.cfs. [4,5]. The calculated exchange cross sections for the inuonic hydrogen nuclei and for symmetric hydrogen molecules are shown in the table. They are given in 10~2Octn2 for several collision energies e. Pfi + d pfi + D2 pH + t PH + T2 dfi + t 0.001 827.7 984.1 384.4 461.3 15.8 20.9 0.004 453.0 519.8 203.9 235.0 8.90 10.9 0.010 283.7 311.8 128.0 140.5 5.64 6.33 0.040 140.7 144.7 63.6 65.2 2.94 3.02 0.100 87.4 88.2 39.9 40,7 2.00 2.01 0.200 G1.0 61.2 28.1 28.2 1.59 1.60 0.500 37.9 38.0 18.0 18.0 1.37 1.37 1.000 26.6 26.6 13.2 13.2 143 1.43 Assuming that the muonic atoms are thcnnalized in the hydrogen molecular target of tem- perature 300 K, we have obtained the following averaged molecular exchange rates (normalized to the liquid hydrogen density): 1 1 lo J 1 \pDi = 1.6 x lQ ^- , V, = 0-7 X 10 s'- , Adr3 - 2.5 X 10V . References: [J] L.I.Ponomarev, Contemporary Physics 31, 219 (1991), and references therein. [2] W.H.Breunlich et al., Arm. Rev. Nucl. Part. Sci, 39, 311, (1989), and references therein. [3] V.S.Meleshik, J. Camp. Phys. 65, 1 (1986). [4] A.Adamczak, V.S.Me'eriuk, L.I.Menshikov, Z.Phys. D4, 153 1986). [5] A.Adamczak, Muon Catalyzed Fusion 4, 31 (1989). 40 Atlas of cross sections for scattering of pn, dfi and t(.i atoms on hydrogen molecules A. Adamczak, V.I. Koiobow and V.S. Melezhik submitted to Muon Catalyzed Fusion This work is the fourth part of the atlas of cross sections for muonic hydrogen scattering on hydrogen nuclei and molecules. It contains tables and figures of the molecular elastic (without muonic exchange) cross sections. Rotational and vibrational transitons of molecules are taken into account. The results for the symmetric case, when all three nuclei of the system are identical hydrogen isotopes, has already been published [1]. The knowledge of these cross sections is important for experiments concerning muon catalyzed fusion and muonic capture by difFerent nuclei admixed to gaseous hydrogen targets [2]. The calculations of the molecular cross sections are based on the respective nuclear cross sections [3], obtained in the framework of adiabatic method [4]. The molecular binding, electron screening and spin-correlation effects have been taken into account according to the method presented in Ref. [5]. It is shown that these effects are essential for collision energies below leV. The short table of cross sections for the scattering łfiĄ- d and tfi -r Dj is presented below as an example. Cross sections are given in 10~"2Ocm2, the target temperatures are equal to 30 K and 300 K. These cross sections are necessary for kinetics calculation of muon catalyzed fusion in D% + Ti mixture. energy tfi + d tft+Vi ' [eV] T=30K T=300K 0.001 10.9 443.5 458.8 0.005 11.5 119.5 129.2 0.010 11.9 62.2 72.6 0.040 13.5 37.7 37.5 0.100 15.6 35.2 38.0 0.250 20.4 44.9 44.1 0.500 27.6 55.8 55.9 1.000 38.0 75.8 75.8 2.000 48.4 96.7 96.7 5.000 55.8 111.6 111.6 References: [1] A.Adamczak, V.S.Melezhik, Muon Catalyzed Fusion 4, 303 (1990). [2] L.I.Ponomarev, Contemporary Physics 31, 219 (1991), and references therein. [3] C.Chiccoli et al., preprint INFN/BE-91/09, Bologna, 1991. [4] S.I.Vmitski, L.I.Ponomarev, Fiz. El. Chastitu At. Yadra 13, 1336 (1082). [5] A.Adamczak, Muon Catalyzed Fusion 4, 31 (1989). •II Search for nuclear fusion reaction in the 3Hefid system D.V. Balin, V.N. Baturin, Yu.A. Chestnov, E.iVi. Maev, G.B. Petrov, L.B. Pettov, G.G. Semenchuk, Yu.V. Snmenin, A.A. Vorobyov St.Peteisburg Nuclear ?hysk3 Institute W. Czapliński, M. Filipowics, A. Gula Institute of Physics and Nuclear Tzrhniques, Mining Academy, Kraków and S. Gula .The aim of the experiment performed within cooperation agreement between Kraków physi- cists and the Petersburg 'TPI was to verify diifrrent theoretical predictions concerning the muon- catalysis of nuclear fusir a reaction d +3 He -> v + a in the zEefid molecule. The measurements were performed using a high-pressure ionisat.U* chamber iuled with a &He + d mixture at room temperature and 90 atm pressure. The chai: Published in AGH Reports INT 250/PS, Krakvw: (1091), submitted to "Muon-Catalyzed Fusion". References: [1] K.Nagamine at al. AIP Conference Muoa Catalyzed Fusion, Sanibel Islands, Fl 1988, AIP Conference Proceedings No.181 [2] D Harley, B.Muller, J.Rafelski, J.Phys. G16 (1990} 281 [3] A.V.Kravtsov at al.,Pis'ma ZhETF 40 (1984) 124 A Fastbus System for preparation oi the COSY-11 experiment M. Ziółkowski and W. Oelert1 1IKP-Forschungszentrum Julich, Germany. The experimental data which will be produced by the COSY-ll detector will be collected by the Fastbus front end electronics as: multihit TDCs for drift chamber, faat TDCa and ADCs for scintillator hodoscope. A small Fastbus laboratory system has been set up for use in such applications in order to: learn and train software and hardware aspects of Fastbus, test Fastbus modules and develope electronics, perform data acquisition in the laboratory for detertor development. 42 The system consists of a Fantbus crate controlled by CERN Fastbus Interface CFI connected to host-dedicated I/O camac register STR 301, pee Fig. 1. The microcomputer cnmac crate controler DSP 6002 provides a link to the IMB-PC computer which executes programs of the useT and acts as an inexpensive peripheral gerver (i.p. hard disc, optical disc, grnphic terminal, printer). The CFI MG8k microprocessor controlls the execution of standard Fastbus functions implemented on board as microcode routines. Fortran written programs running on the PC computer call the adopted CERN Standard Fastbus Library [1]. Execution of Fastbus compound operation liRts (which are preloaded in the CFI master) may be triggered with an external signal. Readout data may optionally be stored in CFI buffer and than transmitted to the host using the DMA mode. This simple Fastbus test system has been proven to be a user friendly tool Kit in the labo- ratory with Fastbiis instrumentation. FASTDUS 5 FB mnstcr CFI STH .100 T/0 rrRjsicr STH 301 Cmnnc-bus controller DSP 0()fl2 IBM-PC Fig. 1. The. architecture of the small Fasibus data acquisition system. References: [1] Users Guide to CERN Fastbus, Routines DD Division, CERN 1988 Construction of a vertex detector consisting of independent induction drift chambers (IDC) R. Broders, M. Dab men, G. Decker, K. KiUan, A. Kurtenbach, C. Lippcrt, W. Oelerl, E. Roderburg. K. Rohrich, T. Sefzick, 0. Steinkamp, R. Stratmann, S. Walsh IFP-r'orschungszentrum Jfflich, Germany and M. Ziółkowski. Strange particles which decay due to the weak interaction have a mean life time of the order of 10"1" seconds. This corresponds for momenta which occur in the COSY region to a decay length in the centimeter range. To evaluate the kinematics of strange particles in a reaction it is very helpful to rec istruct the decay vertex. Therefore it is necessary to measure tracks near the target region vith high spatial resolution. As a detector we chose the IDC [l], as this chamber is able to measure with high precision in a high rate background, which is found near the target. Mechanics We built a detector which is a modular stack of c'rift chambers which are only by 3.5 mm apart from another. Each chamber consists of 3C dnft cells, which are defined by one anode and two potential wires placed between a near (.5 mm) and far (3 mm) cathode (Fig. 1). The active region of one plane is about 20x20 mm . In order to form a hrmogenous electrical field at each side 10 anodes and 11 pote-.tial wires are added. The wires are glued on ceramic frames which have burned in grooves to provide the exact position of the wires. On alternating sides the potential wires and the anodes are soldered on prin'ed circuit boards. The Lircuit boards are made, by flexible caption foils with copper jtrips on both sides [2], The foils are glued in the aluminium frame providing a smooth surface for a sealing ring of the next chamber. All electrical signals and high voltages of the chamber aie supplied by this printed circuit. To each wire plane a ceramic frame v.'itli two cathode foils is attached. One foil is directing to the wire.1 and has a distance of .5 mm to the wire plane. The opposite foil acts as the far cathode for the next wire plane. Each plane can be gas tight connected to the nej-.t plane with one sealing ring. The orientation of the wire direction i3 changing by 120° degrees. The full detector layout is shown in Fig. 2. High Voltage As tne chamber is operated with isobutanc (+5% ethanole) very high voltages are needed to get a gas amplification rf more than 104 . Each chamber is supplied with one voltage source, the voltages axe divided with, a resistor chain and the currents are meaasured with digital voltmsters with floating power supplies (Fig. 3). The high voltage supplies are built modular so it is possible to adjust the gas amplification for ^ach chamber independently. Electronics 400 channels are provided for the read out of the anodes and potential wires, i'iie preampli- fiers aii mounted directly at the end of the flexible capton printed circuits. The ampb'fiers are charge sensitive with a rise time of about 5 nsec. The differential outputs are fed out from the experiment area by 15 m twisted pair cables-. To avoid pile up effects from the long faH time of the chamber signab, they are symmetrized by pole zero shaper. The preamplifiers and shaper modules are developed and fabricated at the University of Siegen with, thickfilm technology. The performance and the programming of th« FADC-system is described in [3] and the computer system for data taking is described in [4j. Measurement A finst measurement wi'h. a stack of esven wire chambers was done at CERN in December 1991. The detector was placed behind the experiment PS185 at the aatiproton storage ring 44 LEAR. During the run three wire chambers had high voltage break downs and could't be oper- ated. With the remaining four chambers ihorc than 1 inilion antiprolon tracks were recorded. for calliade 1 ']< (Anode) - 7 }X m *(r--Wire)=20 /Am 3rr ' 1 I —• 0.6mm J near cathode O.blTlJT) ""' Fig.l. Mecha.nicn.1 parameters of the IDC. UM pju^io! I gas rlcl 36 channel wr board gas cullpl I flexible caplon fol Fig. 2. Schematic view of a stack with three drift chambers. CattvxV 0 on jpa-l Inn vV« plarvl < J„ — Ciffo* 105 crt carl Iran vtt p»vl • U. M wrcs • U> — (Utf pnf^rtii wirtl lor Icłd (rrpirq « U, Fig. 3. High Voltage Distribution. 45 References: [I] A.IT. Walenta el al., Study of the TO'? iu«s a. High lUte Vertex Detector for the ZEUS Experiment, NIM A2G5 (1988) 69; E. Rodert.urg ct al., The Induction Drift Chamber, NIM A252 (1986) 285 [2] The printed circuit rnpton foils were fubmat^d In tbn workshop of Mr. Gandi, CEHN [3] C. Lippert and G. Decker, this annual report [i] G. Decker and C. Lippert, this annual report The use of induction drift chamber signals as a fast trigger R. Broders, M. Dahrnen, G. Decker, K. Kilian, A. Kurtenbach, C. Lippert, W. Oelert, E. Itoderhurg, K. Rohrich, T. Sefeick. 0. Stcinkarap, R, Stratmann, S. Walsh IKP Fotschungsutuivum JuJfth, Germany and M. Ziólkowski Two possible readout schemes of the induction drift chamber (IDC) [I] are reported to get ft fast trigger information: cither by recording '-ho anode wire signals or by the induced signals of «>ne cathode. . The chamber consists of a wire plane with alternating anode and potential wires which are separated by 0.3 mm and two cathode foils with a distance of 0.5 inm and 3.0 mm to the wire plane (see [2] for details). The cathode foils which are produced in the "Targetlabor" of (he IKP consist of 25 /an thick capton foils and are coaled with a layer of 3000 A of gold. Isobutane was used as the drift chamber gas. It has an electron drift velocity in the order of 50 /im/ns at a typical electric field of about 0 kV/r.m in the drift region. Isobutane is a dense gas with a high primary ionization density (40-50 ion pair*/cm for minimum ionizing particles). The presented TDC drift time spectra were recorded [3] with 2.28 MeV maximum energy. The stop signal was obtained from a plastic 3eintillator. The drift time spectra of 4. adjacent anodes of one plane aiv shown in Fig. 1. All TDC spectra have a sharp peak of 6-9 ns FWHM and i tail of longer drift limes. Tht events with longer drift time correspond to inclined tracks, which have in general short response times at another wire in the plane. This betaviour of the TDC spectra is confirmed by a computer simulation of the drift cells. Fig. 2 shows the simulated spectra of 3 adjacent anodes for tracks with an angle of 15 degrees to the normal. All tracks start in cell 1 and the primary ionization dusters are distributed with a. Poisson statistics along the track and the shape of the measured spectra is well described. Another possible readout of the fast trigger signal can be realized by recording the induced signals on the near cathode (distance 0.5 mm to the wire plane). The time behaviour is of course the same as for the anode signals. The use of the cathode signals allows different ...bdivisions of the foils to be made. For a parallel division of the cathode (Fig. 3) the performance of the track separation between the two parts is examined. Therefore the normalized difference of the induced signals is plotted versus the track position, which is measured from the wiie signal? (Fig. 4). A clear separation of the two parts for normal incident tracks can be seen. The combination of very small drift cells together with a high ionization density and a high drift velocity allows the use of the IDC signals for a fast trigger (minimal coincidence length about 10 ns). This increases, for example, th* efficiency of a vertex detector using the chamber signals in a first level triger. 360 380 400 420 440 460 480 360 JflO 400 420 440 460 400 l • • • l •• • • i • • « I i • • I • • • i • i i I i i i i i I i i, • I • • ',1,' • • I • • • i, • • ' I • • ' t- /.. /Stf^for. i60 380 400 420 *40 < CO 480 360 JBO 400 420 4<0 <60 460 TOC-Konol [ni] TOC.-Kono! (ns) Fig. 1. TDC spectra of 4 adjacent anodes. 250 •— Cell 1 — Cell 2 -•• Cell 3 200- ISO u "Ć 100- u 50- -10 0 10 ZO 30 40 50 60 70 Drift time [ns] Fig. 2. Computer simulation of the drift time in 3 cells. Fig. 3. Realized subdivisions of one cathode. 47 1.0- --,-,-,-, —r—,—r "1—i- T—i—[--,—r—i—i—i- ! 0.5- -=s]sijjps a* o.o- o o I -0.5-- 1.0- v .-, ,-,-, ,- i - i—i—i—r-r—j—i—r—i—T--T— r-T—]- -r—r-?~i- I 1 j— 1--I-T— 1 1—I—|— -400 0 400 800 1200 1600 x Fig. 4. Scatter plot of the nonnnlixrd difference of induced signals on two halves versus x-position of truck for normnl incidence. References: [l| A.H. WalentaH al., Nurl. Instr. and Metb. A2C5 (1988) C9 [2] H. Broders el ai., Construction of a Vertex Detector consisting of independent Induction Drift Chambers, KFA Annual Report 1991 [,'}] M. Dahmen, Diploma thesis, Jtl-Berichl, 1992 The induction drift chamber (IDC) at high rate R. Biodersj M. Daluncn, G. Decker, K. Kilian, A. Kurtenbach, G. Lippert, W. Oelert, E. Todcrhurg, K. Rohrich, T. Sefxick, 0. Steinkainp, R. Stratmann, S. Walsh IKP Forschuiigszentnim Jiilich, Germany and M. Ziólkowski The higl) rate capability of the Induction Drift Chamber was tested with 10 MeV protons of the tandem accelerator at the FSrlangt'n University. The mechanical parameters of the chamber are given in [1.]. We tested whether the intense beam produces high voltage sparks or damages, and measured tlie rate dependence of the gas amplification. The rate was measured with a Tektronix 24.07 oscilloscope which has the option to measure tho trigger rate. An indirect measure for the rate was the current between one cathode and ground. For zero rate this current was of the order of lnA. 48 The beam hod a symmetric shape with P WHM = 3-4 nun. The fluctuation of the intensity of the beam during one measurement was less than j>, factor of 2, Results; The maximum rate measured was 2xlO7 protons per second per mm2 . No damages and sparks have been observed. The electrical field is lowered by very high rates due to space charge effects and to voltage loss on the feed resistor. When the beam was switched off, the chamber, recovered in less than a second. In order to examine the dependence of the gas amplification on the rate, the signals of the anodes were recorded with FERA ADC's (the gate was derived from the signals and had a width of 65 ns). Measurements with minimum ionizing 2.5 GeV electrons at the synchrotron in Bonn have shown that the spatial resolution for a gas amplification of 1.5xlO4 is 30 fxm and for an am- plification, of 8xl03 is 40 nvn (0 degree track, evaluated with ADC's). Compared to minimum ionizing particles the 10 MeV protons yield a factor 20 more ionization. Therefore, the rate dependence of the spatial resolution for minimum ionizing particles by a gas amplification of 1-2x10* is given by the measurement with 10 MeV protons at the lowest gas amplification (same ADC entry) (Fig. 1). In Fig. 1. the rate, where the gas amplification is reduced to a factor 2, is marked. The chamber can stand a rate of more than 3xlO6 protons per second, per mm2, without serious deterioration of spatial resolution. 1100- O) 1000-j C d 500 -_ \ 400- U =1600 V 300-i ko V I 200-; -- uta=i5oo v: ••- Uta=1450 V 100- — U"=1350 V o m(r)=--0.5m, 0 0.0 1.0 2.0 3.0 4.0 5.0 6.0 rale r [TO6 parlicles/wire*s] Fig. J. Calculated mean-vaiiic as a function of the rate for different voltage settings on the lirnrt-r cathode. 49 References: [1] R. Broders et al., Construction of a Vertex Detector consis- ting of independent Induction Drift Chambers, this Annual Report [2] R. Broders, Jul-Bcricht, 1992 <)rp Spin correlation in AA-production K. Kilian, W. Oclert, K.Rohrich, Th. Sefeick IKP'Forsclwngszcntrum JiUich, Germany and M. Ziólkowski for the PS 185 collaboration Due to the rather simple structure of A-particle its spin dynamics can be related to the strange quark content. Quark spin correlations of the ss-palr are imaged by the spin correlations of the AA-pair. The spin-vectors of the twohyperons produced in the interaction pp -> AA can be correlated to each other, A matrix with nine spin-correlation-elements [1] describes this property of the produced particle-pair. The parity conservation of the strong Cgy, Cyx, Cvt> Gti/ must be equal to zero. Additionally the elements Car, C« are equal because of charge conjugation symmetry. The spin correlation parameter C,j appears in the complete description of the differential cross section angular correlations in the distribution of the decay bayrons [1]: W{X,Y,ŻX,Y,Z) ~ [{l+aPg?+aPyY)+{C„XX + CvU?Y+C„2Z+CaZZZ+CtaŻ~X)] (1) where: (X,?,Z)(X,Y,Z) (2) are the direction cosines of the decay byron§ in the A and A rest frames, Pv ,Pp is the polarisation for A, A, respectively, dcr/dCl, P, and C,-,- are all functions of the AA scattering angle. The analysis of Monte-Carlo events indicated significant inefficiencies, see Fig. la, due to detector constrains and due to limitations in the evaluation code. Among other a Cxx pseudo correlation for Monte-Carlo events, shown onfig. 2a , is observed. An appropriate correction method is necessary to obtain the true spin correlation parameters. A method developed has been based on the used symmetries in the process pp —> A A -+ pw+pTT~: for each event {Eq. 2) there are three others (Eq. 3), which give exactly the same results. This property results from Eq. 1 and is a consequence of P,C and CP symmetry. (-X,Y,-Ź) , (-X,Yt-Z) (X,-Y,Z) , (X,-Y,2) (3) Adding for each event (Eq. 2) these three other symmetric combinations (Eq. 3) an effective decrease and smoothing of the reported inefficiency is observed . Corrected with this new efficiency data result in much smoother Cy parameter distributions. Figure 1. presents the appropriate corrected matrix fof 34000 experimental events (1.919 MeV/c), Further details will be described in [2]. It is shown that the described method works well to extract significant spin correlation in the AA production experiment. 50 Cxy Cxz „. Cyx CyZ i+H- -H- Czx Czy Q r-^ł-*t- •• •j 0 J > -A 0 J Fig. I. C,j inatrix /or canceled experimental daU (1910 MeV/c). References: [1] F. Tabakin, ILA. Eisenstein, Phyn. Rev. C31 (1985) 1857 [2] M. Zińlkowski, PhD-Thesis, in preparation. COSY-11 detector arrangement A. Budzanowski, H. Dąbrowski, D. Grzonka5, L. Jarczyk2, B.Kamys, A. Khoukaz9, K. Kilian3, M. Kistryn2, M. Kohler3, A. KoKela2, A. Magiera2, W. Oelert3, E. Rodcrburg8, M. Rook3, R. Santo1, R. Schmidt3, J. Smyrski2, M. Sokolowski2, B. Stugu3, A. Strzalkowski2, P. Turek* and M. Ziólkowski 1 University of Miinster 2Tnstitutc of Physics, Jagiciloxiian University, Cracow, 3Institut fiir Kernphysik, Forschungszentrum Jiilich, F.R.G. COSY-11 is an internal target experiment at COSY for the threshold meson production in the mass range up to 1 GeV/c2 . The planned setup of the experiment is shown in Fig.l. together with the tracks of the ejectiles for the pp -> ppK+K~ reaction at a beam momentum of 3.302 GeV/c. The target will be installed in front of COSY-dipole no.8 which is used as a magnetic separator for the ejectiles and allows 0° measurements. The various detector components are drift chambers Dl and D2, scintillation counters SI, S2 and S3 and a silicon strip detector Si. The position and the dimensions of the detectors result from tracking studies of the ejectiles at maximum possible momentum. The target will be a hydrogen cluster target with a density of 1014 atoms/cm3 and a variable dimension [1]. The essential analysis of the various meson production experiments will be a missing mass determination by measuring the two proton momenta accurately. This will be done by the two drift chambers with an active area of 40 cm height 130 cm width. Each of them consists of 6 layers, 2 with vertical and 4 with inclined +31° and -31° wires [2]. The position resolution will be 200 /mi rms in x- and 500 /«n rms in y-direction. The resulting invariant mass resolution for a 1 GeV/c2 meson calculated from the reconstructed proton momenta is 0.2 MeV rms for a target dimension of 3 mm. 51 The trigger signal for our experiment tonics from Ihe scintillation counters. An event is accepted if two protons am rpc.i in the scintillators. SI will cover the whole drift chamber by If) scintillation counters of 10 cm width. The region where the protons puss the scinlillator for reactions with a low relative momentum, will be covered by $2, 16 scintillation counters with a width of 1 cm. All sciutillator strips have a lengths of-15 cm with photoinuUiplier readout on both sides. For the third sciutillntor S3 a scinlillator wall of 2.2 in width and 1 m height, similar to Ihe Amadeus detector [3], is planned. The main feature of this wall is the time of flight measurement of the protons far a further momentum determination. In addition it will be very helpful as a trigger element and for particle identification. The output of S3 will be time, position of a particle liit and its energy loss. The silicon strip detector is installed to detect negatively charged particles especially lcaons for the background reduction in a selective analysis of the charged kaon decay channel of the produced strange mesons. The detector consists of sU'ron pads with the dimension 19 mm x 24 mm divided into 4 strips of 4.6 mm width. They will be installed in the dipole gap in three overlapping rows with a total height of about 7 cm over a lenght of 1.4 m. To reduce the costs of this detector system the readout of the Si-pads is performed by AMPLEX chips and a DRAMS module which were developed at CERN [4]. AMPLEX is an integrated circuit with 16 preamplifier, filter amplifier and sample and hold stages, o multiplexer and an output driver. DRAMS is a CAM AC module which manages the readout, digitizing and storage of up to 1024 AMPLEX channels. The idea is to separate the ultra high vacuum in the COSY-ring (p=10~10 mbar) from only high vacuum regions (p >10~fl mbar) with thin foiL. Thus we avoid the UHV compatibility for the detector installation and the exit foil. The material of the foils, polyamide or metal, is still under discussion. Only the si-pads will be mounted in the vacuum chamber whereas the electronic parts are located oiitside because of the heat production of the cliips. For this reason we will use a plate of plastic material with electric contact pins which will be mounted on thti 1.4 m long window on the left side of the chamber. On the right side the exit foil should cover the whole length of the chamber. To provide a sufficient stability a suspension at the dipole and a further massive suspension outside of the dipole is discussed. Apart from the work on the detector setup extensh a Monte Carlo calculations concerning the detector efficiencies and the trigger rates have been done. In Fig. 2 the detection efficiency for the ejectiles of the pp —* pp(f> at a be-.m momentum of 3.416 GeV/c is shown. The upper curve shows the efficiency for the detection of the two protons in the drift chambers as a function of the invariant mass calculated from the momentum components of the two protons. In a range of 0.5 MeV/c2 the efficiency is 1 and drops to 0.2 at 7 MeV/c2 below the maximum invariant mass. Therefore the setup is an excellent 4ir detector for narrow meson resonances if , for the physics most interesting, the threshold production will be considered. If the detection of a K+ is required in addition the efficiency will drop as shown by the lower curve in Fig. 3. To check the background and the requirements on our data aquisition system we looked at the sensitivity of our setup to all possible reactions with a sufficient high cross section. As an example in table 1 the trigger rated for the pp ~* pp a All mechanical parts of the cluster target are ready and first test measurements of single components were performed. A test setup to produce a hydrogen cluster beam is now installed at the IKP in Munster. 52 • A first prototype of the drift chamber is built and will be tested next. The production of aU drift chambers will start during 1992 in Cracow. t For test measurements of the scintHlator S3, a small representative units is being built. • A prototype of the Si-detector is under construction at the ZEL to test the detector specification and the readout. • The vacuum chamber will be constructed at the ZAT. At the end of 1991 first design studies have started. Table I. Trigger probabilities, cross sections and trigger rates for all possible reaction channels in the case of the pp —> pp Fig. 1. Setup of the COSY-11 experiment. I, in In 1.1....I...,!.,..i....I.,..1.11.1...i l|,,t 53 1.010 1 017 1.018" 1.019 1.02 1.021 1.022*" mass of -meson / GeV/cc Fig. 2. Geomettical efficiency for the pp—*pp4> reaction. References: [1] M. Buschmann et al., Annual report 1990, KFA-IKP, Jul-2462, 229 [2] J. Smyralti et al., Annual report 1990, KFA-IKP, JG1-2462, 203 [3] G. Anton et al., preprint BONN-ME-91-02, ISKP, Univeristy of Bonn [4] E. Beuville at al., NIM A288 (1990) 157 [5] Compilation of cross sectiono, Vol. 3 (1984) CERN-HERA-84-01 Three body equations in nuclear physics J. Jakiel The investigated problem was to use three body equation to test the optical model and to formulate it in the three nucleon limit in analogy to the Faddeev equation. Such OM will be very usefull for investigation of its imaginary part since very little is known about imaginary effective internucleon interaction. ; Many authors suggest connection between methods used in the FRDWBA and the Faddeev equation but none has shown connections between mentioned coupled channels (CO),coupled reaction channels (CRC), finite range DWBA (FRDWBA) and Faddeev methods.The author introduces a new equation (called JLS equation) which describes the finite range three body problem a + A => ej -f C2 + ^3 or: a + A \ a* + A* J B,D are subsystems c,-(-cy (i^j; ij=l,2,3), • means excited states of nucleus (or subsystems), (+) a ground state and excited states. If w<- construct orthogonal and couiplet.fi wave function basis wliich corresponds to live pos- .sililc channels ( •-. (rr,/ł, 7, 8, t) : o - « ł (M)= 14(2,3) 0 = 6 + (o,d)=2 + (l,3) 7 = a + 5-[-d=l + 2 + 3is Lreak — up channel 6 = d+(6,o)3 3 + (2,l) e = (a,b,d) = (1,2,3) and expressions in round brackets mean bound states, than the equation for three nuclei is : Yacf,23 0 {E-H) 0 + YaYp -J •H" = -ffoi + WV, Wife = f(Wj), and ^,-jt are bound states functions, Y are full solutions or optical wave functions. If solution of a Faddeev equation can be written as : 0 3, n pair than we are looking for a solution of the form: 0 wl2 Y + G W13 0 0,n wi3 T.tyi. Wlt Wu 0 (^ - free, ip - distorted, Y - full solutions) which should be in agreement with two proceeding equations. Elastic and inelastic scattering of a-particles on 12C-target O.A. Pankratenko1, A. Rudchik1, M. Makowska-Rzeszutko, E.I. Koshchy2 and Yu.G. Mashkarow2. 1Institute of Nuclear Research of the Ukrainian Academy of Sciences, Kiev, 2Ghorky University, Charków. Angular distributions of elastically and inelastically scattered a-particles from 12C were measured in the angular range from 10° to 150° lab. at a-particle energies 70, 80 and 90 MeV. Experiment was performed using beam of a-particles f-om the U240 cm isochronous cyclotron of the INR in Kiev. The experimental data are analysed in terms of the optical model of scattering. The aim of this work is to get energy dependent optical potential parameters. These parameters will be subsequently used in DWBA and CC analysis of the experimental data of transfer reactions. 55 Measurement of the nuclear reactions induced 12 by the a-particles of Ba=70,S0 and 90 MeV on the C - target O.A. Pankratenko1, A. Rudchik1, M. Makoweka-Rzeszutko, E.I. Koshchy2 and Yu.G. Mashkarow2. 1Institute of Nuclear Research of the Ukrainian Academy of Sciences, Kiev, 2Ghorky University, Charków. The angular distributions of the differential cross sections were measured for the following reactions: 12C(a,3Hc)13C, 12C(a,t)13N, 4 12C(a,p)lbN. Measurements were performed at the Kiev U240 cm isochronous cyclotron in the angular range from 10° to 150° lab. for the incident a-particle energies 3a = 70, 80 and 90 MeV. The aim of this experiment is to study the mechanism of one, two and three nucleon transfer in the energy region where compound nucleus contribution is small. The analysis within DWBA and CC formalisms is under way. We intend to evaluate contributions from multistep processes. Multiprocessor data acquisition system for event-by-event data collection W. Kantor This project was started to develop and build a dat 1. Computer which controls the Camac crattB (Staiburut Jll PDP 11/73+) • 40 MB hard disk drive • 1 MB main memeory o Ethernet controller • RSX 11M + operational system. 2. Computer that controls the whole system and stores the data on a disic (VAX»tation 3100) • 600 MB hard disk • 2.5 GB Exabyte mag. tape drive • VMS operational system. 3. Event Pattern Detector a special Camac module that decodes the event pattern and strobes or clears the Analog Digital Converters. It alao can generate the interrupt to the Starburst. 4. One or few IBM PC computers connected to the Ethernet working under the DECnet PCSA software. They are used for data YiBualteation during the experiment. 56 5. Data acquisition software that controls the whole -ystem and collects the data. It is build of few main parts thnt runs on different computers. • Main module that controls the rest of the system. It runs on VAXstation. It also allows to define the actual hardware setup and start the experiment. It stores tlie data on the external memory and sends the data for visualization. • Visualization module that shows the collected data in graphical mode. It runs on IBM PC. o Camac control module that controls the Analog Digital Converters. It runs on PDP 11/73+. e Hardware definition module that allows to define the actual hardware setup. It runs on the VAXst.-ition. AH modules are working together by means of the Ethernet connection. Up to now about 20% of the work is done. New technique in fabrication of silicon detectors L E. Bialkov.ski Silicon detectors with good resolution and good long-term stability are required in erperi- inents in nuclear physics. With regard to its application in cases wheri thin and thick detectors are needed the fabrication was actively investigated. Three different fabrication processes are commonly used today: the so-called planar process in connection with ion implantation, the •surface barrier technique and epitaxial crystal growth technique. Using the planar process it is possible to manufacture detectors of extremely low reverse current and very precise shape definitions. This allows us to use different kinds of structures in order to obtain optimal results especially in high energy physics. This technique was investigated with The Semiconductor Center, Warsaw, where high temperature processes and lithography were carried out. At prcs nt some limitations exist, mostly because of the non-availability of silicon of required quality. One of the main problems in producing silicon surface barrier detectors -SSBD- with low leakage currents is caused by edge effects. To avoid this problem the SSBD are covered with special epoxy resin. The edge protection of the surface barrier is performed by its coating with epoxy resir both for N and P type silicon. The very thin SSBD, from 3 /im to 20 /im, are produced by application of epitaxial crysttd growth technique. The thickness and the resistivity of the epitaxial layer are well controlled with good uniformity because EPI technique is well de- veloped and widely used in semiconductor industry. We investigated a method of producing thin silicon film supported by a frame of thicker material by selectivr electrochemical and cliemical etching. As can be seen from the following table good characteristics were obtained. active area resolution reverse current thickness 2 type mm keV (FWHM) M /mi SSBD 50 18 0.4 100 SSBD 250 21 0.8 1000 SSBD 50 Noise 21 0.9 5 Planar 100 18 0.005 300 The technique of manufacturing of thick SSBD, up to 2 mm depletion layer was developed hi cooperation with the Institute of Physics, University of Cologne. 57 PUBLICATIONS: I. Articles: 1. A. Szczurek, A. Budzanowski, L. Jarczyk, A. Magiera, K. Mohring, R. Siudak, T. Srokowski, "Alpha particles from the reaction 12C+12C at 28.7 MeV/n", Z. Phys. A - Hadrons and Nuclei, 338 (1991) 187. 2. J. Czudek, L. Jarczyk, B. Kamys, A. Magiera, R. Siudak, A. Strzalkowski, B. Styczeń, H. Hebenstreit, W. Oelert, P. von Rosen, H. Seyfarth, A. Budzanowski, A. Szczurek, "Fragmentation of 12C projectiles interacting with 12C, 27A1, and K8Ni nuclei at energy 28.7 MeV/nucleon", Phys. Rev.C43 (1991) 1248. 3. M. Buballa, S. Drożdż, S. Krewald, J. Speth, "Nuclear electromagnetic response within continuum RPA theory", Ami. Phys. 208 (1991) 346. \, E. Caurier, S. Drożdż, J. Okolowicz, M. Ploszajczak, "Geometrical quantization in the time dependent variational approach", Acta Phys. Polon. B22 (1991) 389. 5. M. Buballa, S. Drożdż, S. Krewald, A. Szczurek, "Final state interaction effects in the (e.e'p) reaction", Phys. Rev. C44 (1991) 810. 6. S. Drożdż, J. Speth, "Near-ground state spectral fluctuations in multidimensional separa- ble systems", Phys. Rev. Lett. 67 (1991) 529. 7. E. Migli, S. Drożdż. J. Speth, J. Wambach, "EO and Ml excitations in E8Ni", Z. Phys. A340 (1991) 111. 8. K. Mohring, T. Srokowski, D.H.E. Gross, "Modelling dissipative break-up of heavy ions':, Nuci. Phys. A533, (1991) 333. 9. J. Okolowicz, T. Srokowski, "Nuclear transients", Acta Phys. Polon. B22 (1991) 653. 10. D. Goujdami, F. Guilbault, C. Lebrun, D. Ardouin, H. Dąbrowski, S, Pratt, P. Lautridou, R. Boisgard, J. Quebert, A. Peghaire, "Search for lifetime effects of an evaporative source using two proton-correlations", Z. Phys. A339 (1991) 293. 11. K.P. Artemov, R. Wolski, M.S. Golovkov, L.S. Danelyan, M. Madeja , V.V. Pankratov, V.?. Rudakov, I.N. Serikov, V.A. Timofeev and J. Szmider. "The a-cluster Structure of the 32S nucleus" Yad.Fiz. 54 (1991) 1185. II. Contributions to Conferences: 1. R. Wolski, I. Skwirczyńska, A. Budzanowski, L. Freindl, J. Jaldel, W. Karcz, J. Szmider, "The properties of 28Si resonances at the 31.5 MeV and 33.3 MeV excitation eiergies via the 24Mg(a,nC)lflO and 24Mg(a,a)24Mg reaction", Proc. of the Int. Conf. on Nuclear and Atomic Clusters 1991, Turku, Finland, June 3-7, 1991. 2. S. Drożdż, J. Speth, T. Srolcowski, "Chaos and the statistical properties of nuclei", Invited Lecture, Brasilian Annual Workshop on Nuclear Physics, Sao Paulo, September 2-6, 1991, to be published by World Scientific; Jiilich preprint KFA-IKP(TH)-1991-35. 3. S. Drożdż, J. Speth, "Spectral properties of multidimensional separable systems in the ground state region", Proc. Int. Conf. on Nucleus-Nucleus Collisions IV, Kanazawa, Japan, June 10-14, 1991. 58 4. A. Adamczak, V.S. Melezbik, "Cross sections of prousses p/i+H , 5. D. Ardouin, C. Lebrun, F. Guilbault, D. Goujdami, H. Dąbrowski» P. Lautridou, R. Bois- gard, J. Quebert, A. Peghaire, P. Euues, F. SebiUe, B. Remaud, "Temperatur« measure- ments on a thermalised system in heavy-ion collisions", Proc. of the XXIX Int. Winter Meeting on Nuclear Physics Bormio, Ed. I. Iori, Italy, January 14-19 1991, p. 57. 6. A.G. Aitokh, Y .A. Buçadov, G.Y. Gridnev, M. Graszecki, V. fflinka, E. Kladiva, S. Kliczewski, M. Madeja, V.A. Nikitin, A.A. Omelyanenko, P. Povinec, M. Seman, A.A» Semenov, B. Sitar, J. Spatek, J. Samider, Yu.G. Teterev, A.G. Zieliński, "Focal plane detector for the projectile fragment separator COMBAS", Proc. of th T. M. Buballa, S. Drożdż, S. Krewald, J. Speth, A. Szczurek, "Final state interaction effects in nuclear electromagnetic response", Annual Conference of the German Physical Society, Darmstadt, March ll-16,ls»91., Bull. Ger. Phys. Soc. 6/1991. 8. M. Buballa, S. Drożdż, R. Jessenberger, S. Krewald, A. Szcz\irek, "Information on proton- proton interaction obtained from (e,e'x) data", Annual Conference of the German Physical Society, Darmstadt, March 11-16,1991., Bull. Ger. Phys. Soc. 6/1991. III. Reports: 1. S. Drożdż, S. Krewald, A. Szczurek, "Density effects in the (e,e'p) reaction", Jûlich preprint KFA-IKP(TH)-199i-30. 2. E. Migli, T.L. Ainsworth, S. Drożdż, J. Speth, "Consistent effective interaction: from nuclei to ruclear matter", Jûlich preprint KFA-IKP(TH)-1991-36. 3. R. Merrouch, H. Delagrange, F. Le'evre, W. Mittig, R. Ostendorf, Y. Schutz, F.D. Berg, W. Kuehn, V. Metag, R. Novotny, M. Pfeifer, A.L. Boonstra, H. Lohner, L.B. Venena, H.W. Wilschut, H. Henning, R. Holzmann, R.S. Mayer, R. Simon, D. Ardouin, H. Dąbrowski, B. Erazmus, D. Lebrun, L. Seaac, F. Ballester, E. Casal, J. Diaz, J.L. Ferrero, M. Marques, G. Martinez, B. Fornal, Z. Sujkowski, "Propriétés du Rayonnement de Freinage dans les Collisions Xe + Au a 44 MeV/nucleon", Nouvelles du GANE» no 38, April 1991, p. 4. 4. R. Ostendorf, H. Delagrange, F. Lefevre, R. Merrouch, W. Mittig, Y. Schutz, F.D. Berg, W. Kuehn, V. Metag, R. Novotny, M. Pfeiffer, A.L. Boonstra, H. Lohner, L.B. Venena, H.W. Wilschut, W. Henning, R. Holzmann, R.S. Meyer, R. Simon, D. Ardouin, H. Dabrowsk*,, B, Erazmus, C. Lebrun, L. Sezrc, F. Ballester, E. Cassai, J. Diaz, J.L. ïerrero, M. Marques, G. Martinez, "Interferometrie HBT Avec les Photons Durs Emis dans les Collisions Entre Ions Lourds", in press in Nouvelles du GANIL, no 38, April 1991, p. 16. 5. Y. Schutz, R. Ostendorf,... H. Dabiowski,... B. Fornal, L. Freindl, Z. Sujkowski, T. Mat- ulewicz, " "First observation of the Handbury-B'rown and Twiss effect in nuclear physics", Report GANIL, Cean, 23 May 1991. 59 CONFERENCES AND WORKSHOPS: A. Budzanowoki 1. 6 International Conference on Nuclear Reaction Mechanisms, Villa Monastero, Varenna, 10-16 June 1991 (Italy). 2. International Conference on Nuclear and Atomic Clusters, Turku, 2-7 June 1991 (Finland), S. Drożdź L Annual Conference of the German Physical Society, Darmstadt, March 11-16,1991 (FRG). 2. Workshop on Chaos and Coherence in Complex Dynamkal Systems, Aspen, Colorado, May 26- June 8, 1991 (USA). 3. Brasilian Annual Workshop on Nuclear Physics, Sao Paulo, September 2-7, 1991 (Brasil). 4. Workshop on Isospin Phenomena, Cean, (GANIŁ), September 26-27 1991 (France). A. Szczurek 1. Annual Conference of tht German Physical Society, Darmstadt, March 11-16,1991 (FRG). INVITED TALKS: A. Budzanowski 1. "Nuclear fragmentation and nuclear temperatures", Vl-th Lit. Conf. on Nuclear Reaction Mechanism, Varenna, Italy 1991. 2. "Alpha cluster emission in heavy ion fragmentation", Int. Conf. on Nuclear and Atomic Clusters, Turku, June 1991, Finland. S. Drożdż 1. "Chaos and the statistical properties of nuclei", Brasilian Annual Workshop on Nuclear Physics, Sa5 Paulo, September 1991, Brasil. 2. "Isospin effects in nuclear electromagnetic response", Workshop on Isospin Phenomena, Cean (GANIL), September 1991, France. LECTURES AND COURSES: A. Budzanowski "Selected Topics in Nuclear Theory" - Lecture at the Jagiellonian University, "Problems of Modem Physics" - Seminar at the Jagiellonian University. INTERNAL SEMINARS: 1. J. Okolowicz - "Fission of hot, rotating n-.iclei", 2. T. Srokow8ki - ''Chaos in nuclear scattering". 3. S. Drożdż - "Quantum geometrical Phases" 4. S. Kliczewoki - "Shell effects in heavy ion fusion". 5. A. Adamczak - "Fusion catalysed by /i-mesic molecules". 6. H. Dąbrowski - "Subthreshold pion production in heavy ion collisions". 60 VISITORS: H.K. Willen - Holland, H.W. Egbertus - Holland, S.E. Shick - FRG, H.G. Paetz-Shick - FRG, F.M. Obermeyer - FRG, C.R. Fitznel - FRG, J. Treusch -. FRG 0. Panki iatienko - Ukraine, A. Totski - Ukraine, M. Zaritski - Ukraine. 61 Department \ < of Nuclear Spectroscopy DEPARTMENT OF NUCLEAR SPECTROSCOPY The Department of Nuclear Spectroscopy consists of two laboratories active in two different fields of research. They have cirurged in the course of historical development from common roots related to the application of various spectroscopic methods and techniques. The first laboratory is involved in nuclear structure and nuclear reaction studies including the modern topics as superdeformation, Giant Dipole Resonances and new insights into heavy- ion reactions, as well as advanced studies of high-spin state structure, shell model states, Gamow-Teller decay and atomic phenomena observed with heavy-ion beams. Although some experiments have been performed in Kraków using the old U-120 cyciotron, the predominant part of experimental work has been done outside our Institute in collaboration with research groups at IKP Juelich, HMI Berlin, CRN Strasbourg, LNL Legnaro, NBI Copenhagen, IKP Munster, GSI Darmstadt, University of Gottingen, Purdue University and ANL Argonue. The reports presented in the following pages involve only those cases of 1991 research, where physicists of our group played a leading role or contributed very substantially to the obtained results. The second laboratory concentrates mainly on condensed matter studies using nuclear methods; here the bulk part of results has been obtained with home facilities. The structure of intermetallic compounds, alloys, minerals and metals have been investigated using the PAC, Moessbauer Effect and Positron Axiibilation techniques. An extensive work has been performed in trace element analysis using PIXE, PIGE, SRIXE, UBS and neutron activation methods in application for ecology, medicine, agriculture and geology. Along with continuous development of Department's computer system, a significant part of the activity is dedicated to extend the instrumental possibilities; the main efforts being concentrated on: - installation of 3MeV Van de Graaff accelerator, - construction of recoil nucleus detector incorporated into multidetector OSIRIS system at HMI Berlin, - building of a BaF2 four-counter set-up for the PAC studies, - construction of dual-beam system for the Isotope Separator, - production of high resolution germanium detectors with emphasis on X-ray detection. Together with the Institute of Physics of the Jagiellonian University the Department organizes every year an international conference with traditional name "Zakopane School on Physics". In 1991 the conference on "Condensed matter studies by nuclear methods" took place in Zakopane in April 13 - 21 (100 participants). 63 PERSONNEL: Head of the Department: Professor Andrzej Z. Hrynkicuticz Deputy Head of the Department: Professor Jan Styczeń Administration: Małgorzata Niewiara Cecylia Szklarz Laboratory of the Stracture of Nucleus Head of the Laboratory: Professor Rafał Broda Research Staff: Piotr Bednarczyk* Adam Maj Jerzy Sieniawski Bogdan Fornal Franciszek Maniawsld Zbigniew Stachura Marian Gąsior Marta Marszałek Tadeusz Walczak Jan Konni cki Witold Mcczyński Barbara WodniecŁa Wojciech Królas* Tomasz Pawł&t Paweł Wodniecki Jadwiga Kwiatkowska Antoni Potempa Jacek Wrzesiński Małgorzata Lach Maria Rybicka Kazimierz Zuber Technical Staff : Jerzy Grębosz Antoni Szperłak Mieczysław Janicki Mirosław Ziębliński Jan Jurkowski Laboratory of Applied Nuclear Spectroscopy Head of the Laboratory: Dr. Józef Kajfosz Research Staff : Kvetoslava Burda Roman Kmieć Stanisław Łazanki Marian Cholewa Stefan Kopta Elżbieta Marcaewska* Małgorzata Drwięga Janusz Kraczka Bogusław Rajchel Ewa Dryzek* Robert Kruk* Bogdan Sepioł Jerzy Dryzek Wojciech M. Kwiatek M. Sudnik-Hrynkiewicz Erazm M. Dutkiewicz Janusz Lekki Jagoda Urban Technical Staff : Luba Glebowa Janusz Łachut Zbigniew Szklarz Roman Hajduk Karol Malinowski Władysław Sieczek Piotr Leśniewski Tomasz Nowak Marian Wierba Ewa Lipińska •Postgraduate students 64 Yrast Isomers in Tin Nuclei from Heavy Ion Collisions and the vhn/2 Subshell Filling R.Broda, RM.Mayei3, I.GJkanlaJ, P/i.Bcnet1, PJ.Daly1, Z.W.Ombowski1, M.P.Carpenter*, R.V.F.Junsscns7, T.L.Khoo2 T.Lauritsen2, E.F.Moore2, S-Lunardf, J.Blomqvist4 The decays of (nh1{i2)" yrast isomers have been studied in a series of proton-rich N — 82 isotoncs extending to the vicinity of the proton drip line. The results []] provide an outstanding illustration of the dependence of E2 transition rates between jn states on eubshell occupation number, they demonstrate that half-filling of the proton hUf2 subshell occurs just below 153 Z = 71 Lu. The counterpart /ijj/2 neutron subshell is being filled in A ~ 116 -r 130 tin isotopes, and one should be able to study (f^n/a)" excitations through this complete series. Already (Win/a)" 10+ isomers are known in 116Sn, U8Sn and l20Sh at one end of the series [2], and in the fission products 128Sn and 130Sn at the other. Missing is any information about analogous isomers in mSn, mSn and mS, for which long 10* half-lives (in the 5 -r lQIfyts range) are expected, Since these N = 72, 74 and 76 tin isotopes are not accessible by fusion- evaporation reactions, we sought to identify the missing isomers using the heavy-ton reactions on 124Sn and I22Sn targets. Even-A Sn nuclei display very regular level systenatics. The known 10+ isomers decay by 10+ -» 8+ —> 7" two 7 ray cascades to 7~ isomeric stales of ^111/2^3/2 character. Similar 7~ isomers in mSn (9.3 ^s), I24Sn (3.1 fts) and 12cSn (6.6 /is) are known from /?-decay studies [3] of high-spin In species. Part of the 7~ feeding in /3 decay occurs indirectly through 7-rays of 281 keV (122Sn), 253 keV (124Sn) and 269 kcV (126Sn), which are almost certainly the 8+ - T El transitions predicted from systo.matics. In a search for the 10+ isomers we expected to find the same 7-rays, together with low-energy 10+ -• 8+ E2 partners, both preceding in time the 7" isomer decays. In experiments the 1 mg/cm2 i;MSn and 122Sn targets backed with lead were bombarded with ps pulsed beams of 325 MeV 76Ge ions from the ATLAS superconducting Fig. 1. Decay data for the 122Sn and 1J4Sn 10+ iso- merie half-life determinations. 0 50 K>0 150 200 TIME linear accelerator at Argorme. The detection system consisted of twelve Comptonrsupressed Ge detectors and an inner ball of 50 BC0 hexagons. The off beam Ge singles (Eyx time), prompt, coincidences and delayed coincidences with BG0 ball were recorded. The analysis provided the identification of the 1O+ isomers in I22Sn and mSn, but the population of the 1O+ isomer in 12(3Sn could not be traced. In t22Sn the expected 8+ -+ 7" transitions were 65 ł i B JE K £ o Q) 6 Sn Isotopes 00 4 ,T 2 o Q i •2 •4 - (a) 116 UO 120 122 124 126 12B 130 100 192 194 196 198 200 202 204 20G A Fig. 2: (a) Measured E2 transition amplitudes for the (f/in/2)n 10+ —» 8+ transitions in even-A Sn isotopes. The full line is drawn through the points to guide the eye. (b) A similar presentation of E2 amplitudes for (vii3/i)n 12+ -+ 10+ transitions in even-A Pb isotopes. confirmed, the E2 partners established as 75.2 keV and 78.2 keV transitions, and the half-lives determined as 62(3) /is and '15(5) /JS correspondingly (see Fig. 1). The extracted transition amplitudes ^B(E2; 10+ —» 8"*") for all even Sn isotopes (except 136Sn) are plotted versus mass number in Fig. 2a. The sign of the E2 matrix element is arbitrary, but fulfills requirement to be opposite in the bottom and top halves of the subshell. The E2 transition amplitude is proportional to u2 - v2, where v7 = 1 - v? is the degree of filling of the /i11/2 subshell. The point of half-filling corresponding to vanishing amplitude happens close to A = 123 or N = 73. This is about 2. units higher than for proton hu/2 subshell. The difference is a consequence of single particle energy spacings; the Sj/2 and to a lesser extent the d3/2 neutron orbitals come well below the /iu/2 state, but for protons at N = 82 all three orbitals are nearly degenerate. The 10+ —> 8+ E2 amplitudes in the Sn nuclei can be quantitatively described by assigning an effective E2 charge ee/y to the f/in/2 130 132 particles (holes). For Sn with pure two holes in the Sn core one obtains ecy/ = 0.88(4)e, which is very close to the eejf = 0.91(4)e deduced in a similar way for J13/2 neutron hole in 2MPb. For smaller neutron numbers the reduction of the E2 amplitude due to the depletion of the hnji subshell is counteracted by an increase of the effective charge. Additional neutron holes soften the core by opening possibilities of low energy 2+ excitations. At the other end, the 110Sn B(E2) value gives an effective charge of 2.1 e, twice as large as the value for 130Sn. In Fig. 2b the transition amplitudes \/fi(E2;12+ -> 10+) for known [4] ui\^ states in Pb isotopes are displayed. Here, the effect of effective charge enhancement is seen very clearly in intermediate 202,200,i98p{j isotopes, since a noticable depletion of the :13/r2 subshell starts at lower neutron numbers. A quantitative treatment of the pair correlations has given [4] the result that the effective E2 charge more than doubles from less than le in 206Pb to about 2e in the lighter isotopes, behavior that is strikingly similar to that observed in the tin isotopes. 1) Purdue University, W.Lafayette IN. 2) Physics Division Argonne Nat. Lab. Argonne IL. 3) Dipartimento di Fisica, Universita di Padova, Padova. 4) Manne Siegbahn Institute of Physics, Stockholm. References [1] J.H.McNeill et al. Phys. Rev. Lett. 63, 860 (1989) and references therein. [2] S.Lunirdi et al. Z. Phys. A328, 487 (1987) and references therein. [3] B.Fogelberg and P.Carle, Nuci Phys. A323, 205 (1979). [4] X.Sun et al. Z. Phys. A333, 281 (1939). 66 Mass, charge and angular momentum transfer in /-•• 4 106Cd -f 54Fe collisions studied by 7-7 coincidences R.Broda, C.T.Zhang1, P.Klcinhein;1, R.Mcnegazzo^, M.Lach, K.H.Maier2, H.Grawe1, M.Schramm7, R.Schubart2, S.HofmanrP Recent results obtained with anticompton shielded multidetector arrays demonstrate the excellent resolving power of the 7-7 coincidence technique. The high-quality coincidence data obtained ".'ith such arrayB allow to study excitations of individual nuclei, products of as compbx process as nuclear fission [1]. Moreover, it has been recently shown [2], that one can also observe the cross-coincidences between gamma rays emitted from two nuclei - the binary .reaction partner product.,, hereby identifying their primary or secondary character. In order to explore further the potential application of this technique in heavy-ion reaction studies we performed the 7-7 coincidence experiment for the 30 Fig. 1. Cross-sections for produc- tion of nuclei in binary reaction.and fu- sion evaporation processes in 106Cd-4-MFe collisions. 67 nuclei and of those; with unfavorable radioactive decays. Fig. 1 displays the obtained cross- soclions for production of specific nuclei in fusion evaporation processes and in various binary reactions taking place in the 10(iCd+5''Fi> collisions. The absolute crofis-section normalization was obtained using the results of earlier measurements of the a-decaying fusion evaporation products performed for tin: same reaction with GS1 SHIP facility [3]. The crosa-sectiona for the fusion evaporation reaction channels agree well with the HIVAP code calculations [3]. The summation of corresponding individual nuclei yields indicates that the fusion-evaporation process represents only 20 % of the total reaction cross-section. From the in beam coincidence spectra with gates set on a specific transition the population of the known excitations in a given nucleus could be determined. In those spectra one could also recognize the gamma lines from the reaction partner nuclei. Usually more than one partner was observed, as expected for data, which are integrated over the kinetic energy loss. The correlation of light and heavy reaction products established from the observed gamma cross-coincidences is summarized in Fig. 2. The data points, independent of the detected coincidence intensity mark all cases, for which the data allowed to conclude positively simultaneous appearance of two final products. The location of points on A\ + A2 lines indicates how many neutrons and protons were lost W6Cd +wFe E = 2V7MeV Fragment cross-coincidences 156 __-— 1S7 158 —- 15? 160 = A,«A, Fig. 2. Correlation of light and heavy fragments tstablished from ob- served cross-coincidences be- tween gamriia-rays of binary re- action partner products. Wher- the total mass of both products is smaller than A1-t-A2=lj30, the missing protons are marked with half-filled (i proton) or filled (2 protons) symbols. n n Heavy fragment mass (most likely evaporated from the excited primary products) in a process represented by each point. One notices that also in a mass region arround the 10RCd target and 5 68 10*Cd rtltiid (xcduili o •'• V'IVI.V"-'.'1- • •'•'••• ' -. I cctUiiofit di»md crtllihini QE OE "UW... •i* o? Ji.i.l. , Fig. 3. TOP: Masa distribution of binary reaction products in 10aCd + 8 the compound nucleus formation. Outside this region the data seem to indicate that partial,; but nearly constant degree of charge equilibration was achieved. The two bottom figures display the population of 6+ and 8+ states relative to the 4+ state population obtained from coincidences observed for even-even products throughout the full mass spectrum. It is dear that the highest spin population is attained by heavy fragments produced in damped reactions and the fission product nuclei are populated at much lower spin values. The progressing data analysis promises more detailed results esspecialy those concerning the angular momentum transfer. 1) IKP KFA Forschung8zentrum Jiilich 2) HMI Berlin 3) GSI Darmstadt References [1] J.L.Durell, Proc. of the Int. Conf. on the Spectroscopy of Heavy Nuclei - Agia Pelagia, Crete, June 1989 [2] R.Broda et al., Phys. Lett B2S1 (1990) 245 [3] S.Hofmann, private communication 69 Shapes and Shape Fluctuations of Hot Nuclei A.Maj, J.J.Gaardhpje1, A.Atac1, B.Herskind1, G.Sleiten1, A.Bracco2, F.Camera2, B.Million2, M.Pignanelli* The experimental studies of the properties o hot atomic nuclei were performed basing on the measurements of the gamma rays emitted in the decay of Giant Dipole Resonanse (GDR) build on excited states in the compound nucleus. The high energy photons were measured by the ,HECTOR (High Energy deteCTOR) multidetector array at the Niels Bohr Institute, Denmark. The heart of HECTOR constitutes of 8 large, 14.5 cm X 17.5 cm, single crystals of bariumdifluoride (BaF2), coupled to the EMI 9823 QA photomultiplier tubes with a quartz window, positioned at the distance of 30 cm from the target and covering effectively « 10 % of the full solid angle. The gain stability of the detectors is monitored by a well defined light pulse from the Light Emmiting Diode, which is fed simultaneously to all of the crystals with a low rate. The eventuall drift of the gain can be in the off-line analysis corrected on the 5 min. basis. In addition, the instrument is equipped with a multiplicity filter consisting of 14 small BaF2 detectors, which serve the double purpose of acting as an efficient time trigger and as an angular momentum selector. The efficiency of this filter is « 20 % for 600 keV gamma-ray energy. The study of the properties of hot atomic nuclei has in the past mainly relied on the measurement of the gamma rays emitted at all steps in the decay sequence, and the subsequent analysis of the spectra based on the assumption of statistical model (e.g. [1] and references therein). This procedure has the drawbacks, that the sensitivity to particular temperature regions is reduced, and that the analysis is dependent on certain parameters which are poorly known at finite temperature. Based on the efficiency and stability afforded by the HECTOR array, we have developed a method to isolate the gamma ray decay originating from the first step of the decay of hot compound nuclei, resulting in a much improved sensitivity to the temperature evolution of hot nuclei. The method relies on the measurement of gamma ray spectra from the decay of nuclei formed at excitation energies differing by the energy removed by the first evaporated particle. The difference of such spectra then corresponds to the gamma rays emitted in competition with the first particle (fig. 1). Furthermore it has been possible to determine the angular distribution of this radiation. The magnitude and shape of the angular distribution, has the advantage of providing information on the shapes and shape fluctuation of hot nuclei, in an essentially model independent way, although an incomplete matching of the spins of the nuclei being compared requires a correction of the measured distributions. 162 In a first study of the Yb compound nucleus at E* w 50 MeV, and lmax w 30/i, the magnitude of measured angular distributions exceeds the magnitude which can be calculated assuming an adiabatic coupling of the GDR to the quadrupole degrees of freedom (see fig. 2). Thus this type of experiments may point to shortcomings of current models for the shapes of excited nuclei or to dynamical mechanisms in the coupling of collective modes to the surface degrees of freedom of hot atomic nuclei. [1] K.A.Snover, Ann. Rev. Nucl. Part. Sci. 30 (1986) 545 1 NBI Copenhagen, Denmark 2 INFN Milano and Milano University, Italy 70 5.0 7.5 10.0 12.5 15.0 L7.5 20.0 22.5 E7 [MeV] Figure 1: Top: Measured gamma ray spectra from the decay of 1G2Yb at E" = 50.8 MeV and 101 Yb at E" = 38.8 MeV. Bottom: The difference of the two spectra contains most of the GDIt gamma rays at E^ - 15 MeV emitted directly from lc2Yb compound nucleus. OJ -O.I -0.2 L 5.0 7.5 10.0 12.5 15.0 17.5 20.0 22.5 E7 [MeV] Figure 2: /12 distribution as obtained from the difference spectrum after correction for incom- plete spin matching. Calculations: adiabatic average over all possible shapes and orientations (full drawn line); equilibrium shape (dashed line). 71 Angular Momentum Dependence of the GDR Angular Distribution in Hot Rotating 162Yb Nuclei A.Maj, J.J.Gaard/>0Jei, A.Atac1, A.Bracco2, F.Camem7, B.MUlion2, M.PignaneU?, E.Rebesco*, A.Virtanen3 The Giant Dipole Resonance (GDR) build on hot 162Yb nuclei has been investigated by measuring the high energy gamma rays present in the reaction 225 MeV 48Ti+114Cd. The compound nucleus 162Y& was excited to the energy E' = 75 MeV. In order to test the tem- perature dependence of the GDR, the nucleus ^'Yb was produced at E* = 63 MeV in the 210 MeV 4®Ti+113Cd reaction. Both studied nuclei had the angular momentum distribution with lmax = 60/» as imposed by the fission barrier. The high energy gamma rays, from the decay of Giant Dipole Resonance, were detected in the HECTOR array. It was found, that both the spectrum shape and angular distribution pattern do not differ for two measured excitation energies for the same angular momentum slices. From the other hand a significant increase of the magnitude of the angular distribution was observed, with increasing angular momentum at the same excitation energy (fig. 1). These two observations are coherent with free energy calculations, which predict an oblate shape for 162Yb nucleus at this excitation energy, with slowly increasing oblate deformation as a function of angular momentum. 3 o ! 3 3 5 3 ? ? ? ? 3 3 5 2 S ? 3. Figure 1: ^-distributicms for three different spin regions. Calculations: equilibrium shape (solid line); averaging over all possible shapes (short-dashed line); averaging over all shapes and orientations (long-dashed line). 1 NBI Copenhagen, Denmark 2 INFN Milano and Milano University, italy 3 JYFL Jyvaskula, Finnland 72 Spin Effects in the Angular Distribution of GDR Photons Prom Hot Rotating Sn Nuclei F.Camera1, A.Bracco], B.Million1, M.PignanellP, A.Maj, J.J.Gaardhoje2, A.Atac? Several experimental and theoretical studies were made in the last few years on the GDIŁ properties in hot rotating Sn isotopes. However, angular distribution measurements were not available. These provide a more sensitive test of existing models of effective nuclear shapes and of the GDR damping mechanisms. The first angular distribution measurements for the Sn mass region were .made with the HECTOR facility. Targets of 61-62Ni were bombarded by beams of 48Ti with incident energies of 203 and 222 MeV {E* = 80,92 MeV, respectively). In both cases the maximum angular momentum is the limiting value allowed by fission (~ 60/i). The aniBotropies were extracted for different intervals of angular momenta of the compound nuclei. The measured aniGotropies increase strongly with spin indicating an increase of the average shape deformation (fig. 1). Angular distribution measurements at lower excitation energies were also made using the reaction 16'17O+94>92Mo at 85 and 70.5 MeV (E* = 65,52 MeV and I = 42,31/L, respectively). The latter are presently being analysed. 1- o o •" C1 n to T- o t- d d d O d d d d d d d d d d d d o d on -0 , I i i I -0 , 1 t ? i ty *V 1 Figure 1: A2 distributions obtained for three different spin regions. Calculations: adiabatic average over all possible shapes and orientations (dot-dashed line); equilibrium shape (solid line). 1 INFN Milano and Milano University, Italy 2 N.BI Copenhagen, Denmark 73 Giant Dipole Resonance in 176Hf A.Maj, JJ.Gaardhoje1, W.Korten1, A.Atac1, Z.Żelazny2, A.Bracco3, F.Camera3, B.Million3, M.PignanellP The HECTOR array was used to study the Giant Dipole Resonance (GDR) in the hot 170Hf nucleus. For this nucleus, with N = 104, similarly to other mid-shell nuclei, the critical temperature at which the phase transition from the prolate shape to the oblate one takes place, re predicted [1] to be relatively high, due to the strength of shell effects. Therefore one can expect Miat this prolate shape will be clearly exhibited by the shape of the spectrum and the pattern of the angular distribution of high energy gamma rays coming from the decay of the GDR built in f - nucleus in heavy ion reactions. The compound nucleus ir6Hf with 16 E" = 58 MeV and lmc. -- 3G was produced using 85 MeV O beam from the NBI Tandem and 1G0Gd target. Jn -dor to narrow the studied temperature region of the decaying nuclei, mostly to the temporal-1....1 of compound nucleus, the differential technique has been applied. For this purpose the lV6ilf nucleus was produced with E" = 49 MeV, differing from that for 17cHf by the average energy removed by the one evaporated neutron. The reaction used was ~A MeV 17O+168Gd The data are being analyzed. [1] Y.Alhassid, S.Levit, J.Zingman, Phys. Rev. Lett 57 (1986) 539 1 NBI Copenhagen, Denmark 2 Warsaw University, Poland 3 INFN Milano and Milano University, Italy Angrlar Distribution of GDR 7-rays from Excited Er Isotopes F.Camera1, A.Bracco1, B.Million1, M.Pignanelli1, A.Maj, J.J.Gaard!i0je\ W.Korien2, A.Atac2, Z.Zelazmf Investigations of the spin and temperature dependence of the GDR angular distributions in Er were made using the reactions i7,i8,iTO+i5O1i4«lM8Nd _> i67,i€6,i65Rr at 85-0) 78.ij 69.8 MeV a (E = 64.2,56.3,48.1 MeV and /wos = 39, 34,20 /i, respectively). The high energy gamma rays were detected with the HECTOR facility. In l6GEr a prolate to oblate transition is expected to take place at around E* = 55 MeV 33 deduced from the analysis of the angular integrated spectra of gamma rays from GDR decay. The Ł?.gular distribution coefficients Ai analysed 60 far are smaller that in Sn. Tius observation suggests that sifialler deformations are reached by Er nuclei and also reflects a stronger influence of temperature and orientation fluctuations. 1 INFN Milano and Milano University, lialy 2 NBI Copenhagen, Denmark • 3 Warsaw University, Poland 74 Gamma Rays from Superheavy Atomic Nuclei T.Ramsóy1, J.J.Gaardli0je], B.Herskinł, W.Korlen\ G'.Sktten1, A.Bracco2, F.Cameni1, B.Million2, M.PignanellP, H.NifeneckeP, F.Schussler], J.A.Pinston3, A.Menlhe3, H.v.d.Ploeg\ J.BacelaS, A.Maj, W.Królas In a pilot experiment in 1989, we have attempted to study the high energy gamma ray decay of the Giant Dipole Resonance in superheavy nuclei prior to fission. The main idea being that, since high energy gamma rays compete favourably with evaporated neutrons at high temperatures, gamma rays will also compete with the fission process providing a snapshot of the heavy conglomerate system before its fissions. The reaction studied was '10Ar+232Th -> 272[108] at incident energies 6.8 and 10.5 MoV/u. The high energy photons from the reaction were measured in coincidence with the identification of the fragments from symmetric fission. Symmetric fission is strongly favoured when using beams of higher energy. The analysis of this first experiment [1] indicates a strong gamma ray contribution from the heated fission fragments. An analysis of this contribution with the statistical model indicates a pre-scission component around 11 MeV (see fig. 1). The strength of this component suggests lifetimes of the conglomerate system of the order of 10~19 - 10~20 sec. This experiment also indicates that fission still competes with gamma emission at excitation energies of the order of 150 MeV. In a new run at SARA, in October 1991, we have studied the same reaction at beam energies of 10.5 and 15 MeV/u with a much expanded and improved setup. In particular we have measured the angular distribution of the GDR gamma rays with respect to the fission plane. We anticipate that at these energies, the retardation of the fission process will lead to a cancellation of the post-scission yield allowing an unambiguous determination of the pre- ecis8ion component. 20 "MMeV? Figure 1: Measured 7-ray spectrum for the reaction at 10.5 MeV, in coincidence with the detection of fragments from the symmetric fission of hot Z = 108, A = 272 nuclei. The 6olid line: CASCADE calculations for the 7-rays from the excited (E* = 80 MeV) fission fragments; the dot-dashed curve: an estimate of the pre-scission 7-emission. [1] J.J.Gaardhtfje, A.Maj, Nuci Phys. A520 (1990) 575c 1 NBI Copenhagen, Denmark 2 INFN Milano and Milano University, Italy 3 ISN Grenoble, France 4 KVI Gronningen, The Netherlands 75 Lifetimes of yrast states in 110Cd 2, S.Juutinenl, RJulin1,A.Virtanen}, P.Ahpnen1, pąp, ,1 ,1 , p C.FahiandeP,dPJHl J.Hattula1, ĄEiĄ.Eąmpinen 1, T.Lónnroth*,TLóh* A.Maj, JU£itom£ DMiijęć/j.Nyberg2'3, 1 7 1 Ą-Fakkąnęn , M-Sugawara ,J_rThor8lun£,J}._Tormanen In the paper by Juutinnen at al. [1] well-developed bands were found in 110Cd, which normally is regarded as a rather good vibrator nucleus at low excitation. Therefore it is interesting to investigate in which extent the transition rates in this nucleus follow the vibrator or the rotor picture. We have carried out a recoil distance Doppler shift lifetime experiment employing the NORDBALL array and a special plunger device for coincidence measurements. The levels of 110Cd were populated via the 100Mo(13C,3n) reaction at 44 MeV bombarding energy. In order to continue the lifetime measurements to higher lying and shorter living states we recently performed also a DSAM experiment at the NORDBALL. In this Au-backed target run the 96Zr(18O,4n) reaction at 73 MeV was used. The results of the plunger experiment are given in Fig. 1 where the relevant part of the noCd level scheme is shown. The RDM data indicate that the ground state band can be identified at least up to I* = 12+. The large J?(E2) values evince that it has a vibrational behaviour up to Z" = 10+. The S-band on tlr top of the aligned (An/2)2 state and the three negative parity bands have been confirmed to be collective. Some evidence for a loss of collectivity with increasing spin in these bands is observed. Transitions feading and deexciting the proposed two-protonfl-(ffg/2)~ 28 + state have been found to be non-collective. In the DSAM experiment Doppler broadened lines in the spin region of about 18 h up to 26 h have been identified. The analysis of these data are in progress. [1] S.Juutinen et al., Z. Phys. A33G (1990) 475 1 JYFL Jyvaskylla, Finland 2 NBI Copenhagen, Denmark 3 SL Uppsala, Sweden 4 Abo Academy, Turku, Finland Figure 1: (next page) A partial level scheme of ll0Cd with the arrow widths representing gamma intensities as they were observed in ihe 13C reaction. Preliminary mean life results are shown in the figure in ps for each level they were obtained from the present data. In square brackets are given the transition B(E2) values. 76 1224 15" 16ł <1.5p3 932 1075 (>t2 W.U.J 786 13" 1.5(3) t2~ 4.7(5! 14 2.0(2) 12" 1076 [12J (10*) 910 8.9] 854(29] 811(37] 1106 10" 12' 12.0(6) I 1.5(2) 11" — io+ ł 0.9(2) 10 561(39.1] 602180]/ 1435 10ł Ę? 800(40) 8T* 171(31] I tf 5] \ e* / 77 Cross section ratio for pn and d emission as a probe of level density for light-medium nuclei P.Bednarczyk, E.Bożek, B.Fornal, M.Lach, A.Maj, W.Mcczyński, T. Pawłat, J.Styczeń In a compound nucleus decay the same evaporation residuum may be reached by different exit channels. For example, emission of np or pn as well as emission of deuterons leads to the same final nucleus. The difference is that the cascades of np or pn pass trough an intermediate nucleus, whereas ^evaporation brings the decaying system directly to the final nucleus. One can expect that the competition between these two processes i.e pn or np evaporation and d emission would reflect the structure of intermediate nuclei. Three nuclear reactions were used to investigate the pn and d competition. The 51V, B4Fe and B9Co metallic targets were bombarded with the 26.5 MeV a beam from U-120 Krakow cyclotron. Coincidences between 7-rays and light charged particles (p, d, ex) were recorded event by event. A telescope was placed at the backward angle 0=140° to select particles evaporated from the compound nucleus, while gammas Were measured with a Ge(Li) detector positioned perpendicularly to the telescope axis. The ratios cfpnl^d were extracted from the experimental data. We have compared the (Tpn/a-j values with predictions of the evaporation code CAS- CADE [1], Such calculations showed that this ratio was very sensitive to the level density as the function of excitation energy of the residual nucleus. The character of this dependence has been tested by varying the level density parameter &ŁDM• The ratios obtained from the calculations with the standard &LDM=A/8 and other appropriate ingredients such as RLDM yrast line, mass formula parametrization etc. overestimated the experimental values by factor of about 2. Strong changes of the ffpn/crj ratios were noticed when altering the level density in the intermediate nucleus. The calculations with a£pjif=A/9.3 fit much better the measured ratios as shown in fig.l. 200 180 • experiment • cajc. pu)M=A/8. 160 O cale. aLDu=A/9.3 140 Figure 1. The erpn/cd ratios 120 obtained from experiment and CASCADE calculations If 60 40 20 0 78 Also, singles proton and deuteron spectra obtained from these calculations with a££>Af=A/9.3 fit experimental points very well. Fig.2 shows the level density curves for the MCr daughter nucleus of BBMn compound system decay, calculated for two sets of the parameters. Noticable discrepances for excitation energy above 10 MeV are observed. Figure 2. Level density curves for the B4Cr nucleus 10 13 16 20 23 26 30 33 Excitation energy (MeV) It should be mentioned that when using the modified version of the CASCADE code by M.N. Harakeh [2], one reproduces the experimental crpn/ffa values resonably well with the a£i>Af=A/8. But the level density function remains like solid curve shown in fig.2 and the strong dependence of the crpn/crj on the &LDM parameter is still observed. A similar conclusion on the level density parameter was drawn in Ref. 3 where the value &LDM =A/9.5 is necessary to describe the GDR 7-decay spectrum for hot ^Cu compound system when using the Puhlhofer's approach. References F.Puhlhofer, Nuci. Phys. A280 (1977) 267 M.N.Harakeh et al., Phys. Lett. 176B (1986) 297 [3] M.Kicinska-Habior et al., Phys. Rev. C36 (1987) 612 79 An approach to study high spin states in 45Sc via fusion evaporation reaction P.Betlnarczyk, W.Męczynski, R.Broda, J.Styczeń in collaboration with LNL INFN In the S7/2 shell nuclei, both protons and neutrons fill the same f7/2 major shell. Those nuclei have been much explored in various spectroscopic investigations of low and moderate spin range. In consequence, the yrast and nearyrast states appear to be largely explaind by the shell model calculation using (fC#3) configuration space alone and the empirical effective interactions [1]. On the other hand, several properties in those nuclei can be explained on the basis of the assumption of collective motion, especially in the middle of the shell. Band mixing calculations reproduce as well level spectra and electromagnetic properties of natural negative parity states in w number of cases [2,3]. Of special interest are positive parity intruder states, due to i3j2 hole excitations in the odd-fr/2 shell nuclei, which constitute rotational-like bands with a deformation parameter /3 « 0.25 that has been inferred from the experimental J9(E2) values (4]. However, the data are rather limited to relatively low Bpins, therefore a more severe testing of the collectivity in both negative and positive parity high-spin excitations is not possibile. The defficiency of the experimental data has been caused by apparent difficulties in extending the heavy-ion reactions to higher bombarding energies in order to achieve higher angular momentum transfer. Those are e.g. large Doppler shifts caused by high recoil energy, and increasing complexity of gamma spectra due to opening of many reaction channels. 400 180 , 30Siat65MeV 320 240 o u 160 250 620 990 1360 1730 2100 Energy(keV) Figure 1: The coincidence 7-spectnun gated with the A = 45 mass (see insert) on the RMS spectrum, measured at 65 MeV of 180. 80 The '16Sc nucleus was already investigated in 30Si(180,p2n) reaction at 38 MoV [3] beam energy. Negative parity states were observed up to tentatively 21/2", 23/2" at 5.4 MeV and the positive parity quasi-band terminated already at Jn = 13/2+. In the present work we used a similar reaction but at much higher energy of 55 and 65 MeV of 180. At 65 MeV, according to CASCADE code calculations, we can achive as high angular momentum transfer to the residual nucleus as 26 h which is by 10 units higher than in previous studies of Ref.4 and still the yield for 45Sc remains relatively high. However, at that beam energy several reaction channels are opened, therefore we made use of the LNL Recoil Mass Spectrometer to measure gamma-recoil coincidences. The gamma-rays were detected with 4 germanium detectors in BGO shields. Fig. 1 shows preliminary results. It is clearly seen from the 1725 keV 7-transition intensity that the highest known state (suggested as 21/2" or 23/2") is strongly populated. Detailed data analysis is in progress. References l E.K.Warburton et al., Phys. Rev. C34 (1986) 136 i B.Haas et al., Nuci. Phys. A246 (1975) 141 3 P.G.Bizzeti et al., Nuovo Cimento 28A (1975) 25 [4] J.Styczeń et al.,JVtici. Phya. A262 (1976) 317 81 A comparative study of superdeformation in i46,i47,i48Gd. Possible manifestations of the pseudo-SU3 symmetry, octupole shape susceptibility and superdeformed deep-hole excitations." K.Ziiber, D.Balouka\ F.A.Beck1, Th.Byrski1, D.Curien1, G.Dc France1, G.Ductene1, C.Gchringer1, B.Haat>\ J.C.Merdinger1, P.Romain1, D.Sanios1, J.Siyczeń, J.P.Vivien1, J.Dudek1, Z.Szymański7 and T.R. Werner2 "Excerpt Jrom Phya. Lett.,3354(1991)308 In this letter, we present first the experimental results on two SD bands in the nucleus 147Gd. Then the theoretical interpretation will be discussed. The experiment was performed at the Strasbourg MP Tandem accelerator. Gamma raya were de- tected with the "Chateau do Cristal" 4ff-detection system which consists of a 38 element BaF2 calorimeter surrounded by twelve Compton-suppressed Ge detectors with 80% efficiency each. The states in 147Gd were populated by the reaction mSn(3oSi,5n) at a beam energy of 155 MeV. The compound system was formed at an excitation energy of 82 MeV and a calculated maximum angular momentum of 68 h. With a hardware threshold of 3 on the number BaFj detectors firing, a total of 300xl06 Ge-Ge-BaFa prompt coincidence events were recorded. At the same time, we have exploited the specific presence of the 550 ns isomer at 8.5 MeV excitation energy in I47Gd M to select the residues corresponding to the 5n exit channel. The recoiling nuclei were stopped in a lead catcher foil positioned inside the castle at about 20 cm distance from the target such that it was out of view for the Ge detectors. By requiring that at least two delayed 7 rays from the ^ isomeric state are detected in the calorimeter it was possible to separate clearly the pro.npt transitions above the l=Tp level, from transitions in neighbouring nuclei as well as from the complex decay of the isomeric state itself. The two bands have also been observed when analysing the corresponding prompt Ge-Ge matrix. UTGd(I) UTGd(II) E (keV) E (ltcV) 7 7 M%) 6635 34(10) 779.1' 37(12) 6963 79(16) 820.9 73(12) 745.7 97(15) 877.2 93(15) 785.4 118(22) 928.6 74(12) 846.7 100(15) 981.5 100(15) 899.9 94(14) 1035.3 93(15) 9S4.4 107(15) 1090.3 102(22) 1009.2 101(10) 1146.4 81(10) 1065.3 90(9) 1203.1 111(20) 112C.7 100(10) 1261.0 81(10) 1175.2 75(9) , 1319.0 57(17) 1228.6 72(9) 1378.6 40(20) 1277.0 66(8) 1438.8 34(28) 1323.3 51(8) 700 BOO 900 1000 J100 1200 1300 H00 1367.1 35(7) ENERC 1413.7 13(7) Fig.l. Efficiency-corrected ipectr* (or the two ED bandi obierved Table 1. The energy and reWtivo Intensity of "Y*1**1 obiefved in the H7 Gdaa • The itiieti ihow the relit i vo inb&d intcmUlei of the two luperdeformed bindi of Od (tee flgl)- The lnten»ilia» of Ifsniltions from th« two SD bind*. bft-nd I and bund II arc norm»lized to 100W for the B-y =840.7 and 081.5 IteV tranvltlona, r«ipectiv«!y 82 Band I (strangest populated) is composed of 16 transitions while band II (weaker) comprises 13 transitions. The transition energies and transition intensities are given in table 1. Examples of 7 spectra are shown in fig. 1. For each band we present a spectrum obtained by summing the cleanest gating transitions. The intensity of band 1 corresponds to about 1% of the ón channel (approximately 0.5% of the total fusion evaporation cross section) whereas the intensity of band II is 0.6(2) of the previous one. Like in rll other nuclei in this mass region where SD bands have been discovered, we could not observe any linking transitions to the normal yrast line. However, it i« clear from our data that the decay of both bands must partly feed the long lived isomcr. The discovery of the two superdeformed bands iu 14TGd together with the knowledge of the superde- formed bands in the neighbouring l46Gd W and 1-lsGd W nuclei leads to the following interesting observations. The gamma ray energies of band I in 147Gd are close, within at most 6 keV, to those in 1-18Gd. The cor- responding differences are still markedly lower than the 10 keV limit discussed above and we refer to this situation as to a direct twin structure. A similar direct-twin structure is formed by band II of 14TGd and that in 146Gd. A comparison of the first band in 14TGd with that in H6Gd leads to an indirect twin relation (i.e. to the equality of the gamma-ray energies in one band to the corresponding average gamma-ray energies in the other) with an even better accuracy of the order of 1-4 keV. The same indirect twin pair of bands is formed by the second band in lł7Gd and that iu mGd. We thus conclude that Lti ihe four bands form a family of structurally close relatives. The interpretation of the experimental results is based on the cranking model used to generate the .single-particle states in a potential-well rotating with frequency w (see discussion in letter). We conclude that the observation of two superdeformed bands in 147Gd together with the existing data in 1<1GGd and l48Gd obtained by other authors reveal new fascinating aspects of nuclear structure. First of all, the existence of the direct and indirect twin-bands in the superdeformed Gd nuclei is most probably connected with the approximate pseudospin symmetry. Secondly, the experiment presented brings a first hint concerning octupole distortions (or at least octupole softness) in the superdeformed region. Finally, the existence of many particle many-hole states in nuclear configurations in the observed region of rotational frequency may be connected with the formation of the superdeformed states at large u and then their diabatical evolution into the observed region as deep-hole states. 1 Centre de Rcchcrches Nuckaires, Universite Louis Pasteur, Strasbourg,France 7 Institute for Theoretical Physics, University of Warsaw, Warsaw, Poland References [1] O.Bakander, C.Baktash, J.Borggreen, J.B.Jansen, K.Kownacki, J.Pedersen, G.Sletten, D.Ward, II.R.Andrews, O.Hausser, P.Skensved and P.Taras, .Vuc'. Phys. A380 (1982) 93. (2] G.Hebbinghaus, K.Strahle, T.Rzaca-Urban, D.Balabanski, W.Gast, It.M.Lieder, ll.Schnare, W.Urban, ll.Wolters, E.Ott, J.Theuerkeuff, K.O.Zell, J.Eberth, P.Von Brentano, D.AIber, K.H.Maier, W.Schmitz, E.M.Beck, H.Hubel, T.Bengtsson, I.Ragnarsson and S.Aberg, Phys. Lett. B240 (1990) 311. [3] M.A.Deleplanque, C.Beausang, J.Burde, R.M.Diamond, J.E.Draper, C.Duyar, A.O.Macchiavelli, R.J.McDonald and F.S.Stephens, Phys. Rev. Lett. 60 (1988) 1626. 83 Gamow-Teller Decay of 0.5 s 27/2" High Spin Isomer in 149Dy P. Kleinheinz1, .1. Styczeń, R. Menegazzo1, H. Gueven1, W. Meczyński, J.L.Tain2, G. Walter3-5, A. Huck3'5, G. Marguier3-5, D. Schardt4, ISOLDE-coll.5 Beta-decay of high-spin inultiparticle states at high excitation has been observed only in few cases. It is found in spherical nuclei near the closed shells where the combination of attractive residual two-body interactions can significantly lower the state with fully-aligned angular momenta which then may become isomeric with a lifetime surh that fast /9-decay can compete. 2661 1.96ml r 1tO8( vir 2550 I Q «6A7H(V f r a tŻ GTx 1.1% 2252 f!l r- 17/?' M78i||E2 • \ 12.5m 1073 -1 13/2' 1073.11BE3 B 0 Ij 7/2* ah,1/2 1672 23/!' 290^ U 1382 L? — 19/2' 559.6 E2 1.0 15/2" 786.5 E2 1.2 V2min 36 n/2' 1/2* Figure 1. The decay scheme of the 27/2" isomer in l49Dy. 84 A 27/2 JEomer in l49Dy has been known and it is characterized as fully-aligned \^i2vf-,j2 configuration state. Its Gamow-Teller decay should populate JT/JJ 1/2^^9/2^/7/2 three-quasiparticle states in the U9Tb daughter nucleus. Therefore, a study of this decay can provide information on the high-spin ^hnj2uhQj2 residual two-body interaction. The activity of 27/2" l49Dy was produced at ISOLDE in spallation reactions of tantalum with 600 MeV protons. It was collected on tape for 200ms and was measured for 1 sec with the Ge-detector set up. The singles spectra were recorded in eight 0.125 sec subgroups for 7-ray half-life identification. In our singles spectra U9Dy 27/2" accounted for approximately 1/6 of the decays. The u0Dy ground state (4.1 min) and 14%o ll/2"(21sec) contributed 2.5 and 1.5 times more decays. The U9Tb 11/2" (4.2 min) had about the same intensity as the U9Dy 27/2" isomer v.-hile 1<19Ho 1/2"1 (58 sec) and U9Tb l/2+(4.1fc) were 20 and 4 times weaker. It is clear that under these conditions study of a weak GT-decay branch of the iĄ9Dy 27/2" isomer is difficult, but the very high statistics obtainable at ISOLDE allowed to investigate it with &ood accuracy. The results of our measurements on the u9Dy decay are jhown in Fig. 1. The measured .coincidence data clearly showed a cascade of 5 7-rays and their apparent decay half-life of 0.5 sec demonstrated that they were emitted following the 27/2" decay. Coincidences with an- nihilation radiation conclusivply characterised them as 7-rays in the /3-decay daughter 149Tb. For the 2664 keV state I* = 25/2" or 29/2" was previously suggested [1] but our data firmly establish it to be a (jrnn/2Ł'/i9/2/5/2)25/2~ state. Within the accuracy of our data, the five U9Tb 7-rays have equal intensities, indicating that the /3-decay proceeds entirely to GT this 25/2" state. From the 7-intensities, the /3-decay branch results in IGTK^Y£ + ^ ) ~ U9 1.12(10)%. The timing data give the isomer half-life as T1/2 = 496(14) ms. The Dy ground state QEC-value has recently been measured as 3.812(i2) MeV [2]. Using the pertinent excitation energies, the measured half-life and the decay branch, we obtain log fi(l49Dy, 27/2- =^'19 Tb, 25/2") = 4.08 or BGT = 0.32(2)^/4* . The BQT -value is only two thirds of the usDy ground state decay [3]. The quantitative interpretation of the GT-strength would, however, need more detailed theoretical analysis. 1 IKP, Forschungszentrum Juelich, 2 IFC, Burjassot, Valencia, 3 CRN, Strasbourg, 4 GSI, Darmstadt, 5 CERN, Geneve References [1] N.C. Singhal et al., Can, J. Phys. 57, 1959(1979). [2] H. Keller et al., GSI, Darmstadt, Sci. Report 1989, p.19. [3] P. Kleinheinz et al., Phys. Rev. Lett. 55, 2664(1985). 85 The Proton-Neutron h-n/ohcwo Residual Two-Body Interaction J.Styczeń, P. Kleinheinz1, R. Menegazzo1, M. Lach, J. Blomqvist2 Experimental determination of the 7r/Jii/2'y''9/2 two-body interaction in nuclei above u6Gd is of crucial importance for analysts of the GT-decays and shell model calculations in this region. From usGd GT-decay one knows the l+ interaction but the other nine multiplet members can only be excited through compound-evaporation reactions where they are rather poorly populated as they lie > 1 MeV above the usTb yrast line. Alternatively, these in- teractions can be extracted from raultiparticle configurations including x/in/2 an(i ^n/z m neighbouring nuclei. The Ui)Dy 27/2" decay data clearly identify the the 25/2" and 27/2" states of the three quasi-particle configuration ^h\i/2v^o/2uf7/2 m 1 i>h9/2 state in the N — 83 nuclei when /iuy2 proton pairs are added above Gd. The 9/2" state is observed in the isotoues up to YoZYb and its energy decreases regularly from 1.397 MeV in u7Gd down to 0.567 MeV in 15376. 86 The calculated 9/2 excitation energies are obtained from multiparticle recoupling calcu- lations as the relative energy of the lowest (Trh^,2uh9^)Q/2~ and (^h^j^hg^)! /2~ states, using the 1.397 MeV single particle energy in 147Gd. Such calculations naturally also give the yet lower Agyj energies for the N = 83 nuclei above Yb. They predict that latest 1590s should + + have a uh9/2 ground state. The estimated 2 to 8 energies of 1.13,1.57,1.67, 1.61,1.69, 1.65 MeV, respectivly, together with the l+,9+ and 10+ energies discussed above reproduce the three known 1//19/2 excitations above Gd within less than 15 keV (Fig.l). (The estimated 8+ energy corresponds nicely to a level observed in u8Tb at 1.654 MeV [3] which is interpreted as belonging to this multiplet). vh9/2 1222. N = 83 rchj^ v States vf 7/2 Figure 1. The vh^/i excitation energy in N = 83 isotones compared with calculated results (italic numbers). 1 IKP, Forschungszentrum Juelich, 2 MSI, Stockholm. References [1] P. Kleinheinz et al., this Report, [2] M. Lach et al., Z. Phys. A341, 25(1991), [3] J. Styczeń et al., this Report, [4] M. Piiparinen et al., Z. Phys. A337, 387(1991). 87 The Level Scheme of 148Tb from 6Li and 7Li Reactions J. Styczeń, M. Lach, P. Kleiuheinz1, W. Starzecki, G. de Angelis1, B. Rubio1, H.J.Haelm1, R.Reinhardt2 , P. von Brentano2 The nucleus usTb has two 0-decay isomers, with /* = 2" and 9+, which are interpreted a? the antialigned ^3/2^/7/2 and aligned 7r/jji/2'y/7/2 configurations. A number of excited low-spin 7rf-state8 with / < 4 have been identified in a recent [1] study of the 148i?j//3-decay, but except the 9+ isomer no other high-spin TTf-states were known, and also the relative energies of the two /?-decay isomers were not well determined. Figure 1: The level scheme of 148Tb. The states arc groupped in muliiplels which cor- respond to the assigned proton-neutron particle-particle or particle-hole configurations and proton-neutron coupled to 3~-octupol(.! configurations. The gamma-transition intensities are drawn as observed in 'Li induced reactions. The inuIlipolarHios aro indicated when deter- mined from electron conversion spectra. Thf nauo.sec.ond half-lives were obtained from 7-7 time spectra in the ("/./,2») reaction. 88 We have investigated 148T6 through in-beam 7-ray compound evaporation experiments on 14iSm bombarded with 6Li and 7Li beams from the Tandem of the Cologne University. Gamma-rays were measured with the OSIRIS 12- detector Compton-suppressed rnultidetector array including two planar Ge- diodes for low-energy 7-detection. Transition multipolarity information derived from DCO-ratioa, singles 7-ray excitation functions, angular distribution measurements, and singles conversion electron spectra taken with a mini-orange. These measurements identified a significant number of 7rf-excitations below 1.8 MeV with spins down to 2. The uaTb levels observed in these reactions are Bhown in Fig.l. With the /'-values quite firmly determined, the states below 1 MeV can be assigned with some confidence to specific 7rt/-multiplets. Above ~ 1 MeV members of the ir/hi/2l'/7/2 X 3" octupole multiplet appear, similarly as they have been identified [2] in u&Eu, and a succesful quantitative analysis of their anharmonicities is made. A significant result of our study is the complete identification of the Tr/iu^/V/a multiplet, which provides a connection of the 9+ and 2~ isomers defining the 2" state of the vd^vh/i configuration as the u$Tb ground state. Of particular interest are the states at 1484, 1654 and 1723 keV which are assigned, although tentatively, as 10+,8+ and 9+, respectively. They are interpreted as high spin states arising from the proton-neutron /ij 1/2^/2 configuration. Thia residual ^-interaction (see Ref.[3]) is important in the shell model calculations and understanding the Gamow-Teller decay strength in this region of nuclei. The states above 2 MeV are in general poorly assigned except some strongly fed. They are interpreted as predominantly arising from three-particle one-hole configurations of the type ^/V/aTdg/jj and h2fj 1 IKP, Forschung8zentrum Juelich, 2 The Cologne University. References [1] P. Kleinheinz et al., Phys. Rev. Lett. 55, 2664(1985), [2] A. Ercan et al.,-Z. Phys. A329, 63(1988), [31 J. Styczeń et al., thia Report. 89 + Directional Polarization of the (7rh11^2)o Pair in the U9Dy Ground State from a Study of its GT Decay W. Mcczyński, K. Zuber, R. Broda, R. Menegazzo1, P. Kleinheinz1, M.C. Bosca2, P. Paris3, C.F. Liang3, J. Blomqvist4 U9 High precision data on Dy Gamow-Teller decay proceeding as (x/iJ1,2)Of.i'/7/2 ~» (7r/ln/2i/'l9/2)i+I//7/2 have been obtained at the ISOCELE II on line mass separator. More than 90 % of the total decay strength is identified in the high-quality gamma- and conversion electron measurements. Spin parities are determined for essentially all 64 U6Tb excited states populated in the decay (Fig. I - see next page). The structure analysis of the new UBTb levels is still in progress. Here we focus only on some interesting features of the GT-strength function. Of the total /3-decay intensity 94.7% feeds into firmly assigned 5/2", 7/2" and 9/2" states and can therefore be attributed to 149 I40 GT-decay of the Dy ^h\x ,2 pair proceeding to T6 3qp-states of vfTj^uhgjiTrh^j-^xA. character expected above 1.6 MeV excitation. Experimental GT strength distribution B(GT) (5/2 : 7/2 : 9/2) = 3.57(17) : 3.36(12) : 5.07(16) is in clear disagreement with the 3 : 4 : 5 ratios for a pure h^f parent configuration. This discrepancy is atributed to the spatial + polarization of the 0 proton pair by the 7ri/ interaction causing an h|+ admixture in the Dy ground state. The shell model witli empirical two-body interactions [1, 2] predicts 3.27 : 3.41 : 5.16 in good agreement with experiment. Only precise /?-decay studies can test this important polarization effect. 1 IKP Forschungszentrum, .Tuelich, 2 University of Granada, 3 CSNSM, Orsay, 4 MSI, Stockholm. References [1] P.J. Daly et al., Z.Phys.A2Q8, (1980)173, [2] J. Styczeń et al., Proc. 5ih Int. Conf. Nuci far from Stability, Ontario, Canada 1987, p.489. 90 l-?2a~^"^:a;a TfTfl^j^" ....=-f s: ! Fig.l: Energy levels in l49Tb populated in GT—decay of l*9Dy feeding into MV/2 * (Thil/2 l/n9/2)l* 3qp—states above 1.6 MeV excitation. Gamma—decay proceeding to the 4.1 h '^^b irsyj ground state is shown to the left, and to the 36 keV 4.2 min Thn/2 isomer to the right. Total transition intensities are given in 10 "3 per parent decay; multipolarities are from conversion electron data. The figure includes oniy one third of the firmly placed 7—rays (with intensities > 2« 10~1), and two thirds of the observed l*5Tb levels. All data, are considered in the log ft value and in the quoted total GT transition strength. 0. Shell model interpretation of the yrast states in 145Sm M.Piiparinen1, Y.Nagai1, P.KleinheinP, M.C.Bosca4-, B.Rubio5, M.Lach, J.Blomqvist6 The present study of H5Sm is based on (a,xn) experiments carried out at the Jiilich cy- clotron with a-beams of 55 and 63 MeV bombarding energies on 145Nd and 146Nd targets. The 4-parameter 77-coincidences, angular distribution- and in-beam conversion electron mea- surements have firmly established the 145Sm high-spin states up to / = 25/2+ at 3.5 MeV excitation. The experimental results in form of the level scheme are shown on the left in Fig. 1. 3.5 2.S 2.0 EipirJntnt -ISO. >*„, _L •, , I im- \vr w v/r n/r n/J* «n4 n'2* ivr Kir Figure 1: High-spin states in 145Sm. On the right excitation energies of odd- and even-parity states calculated from shell model are compared with experimental results. The 14SSm high-spin levels can be described in the framework of the shell model as the 1 l4 couplings of the fr/2 valence neutron to the ' Sm-core excitations [1]. The character of the lowest observed excited state, 13/2+ at 1105 keV, has been discussed elswhere [2,3] and interpreted as the fully aligned member of the ///7/2x3~ particle-phonon septuplet. The higher lying negative parity states up to 19/2" are formed by two proton-holes and fj/2 neutron particle. Detailed shell model calculations using empirical two- and one-body interactions as well as pertinent ground state masses reproduce the experimental energies specifying their configuration assignments. The Fig. la presents the results of these calculations for the Sm 7r-2f/ 3qp-states. A definite classification for each individual positive parity level observed in 145Sm is not possible. Shell model analysis shows that below 3.6 MeV excitation, positive parity states of similar spins arise not only from the (1 92 The calculated energies of the positive parity states from different couplings are compared with the experiment in Fig. lb. Details of measurements and compilation of the input data used iu calculations has been recently published in Ref. [4]. References [1] R.Pengo et al., Proc.Symp. on High-Spin Phenomena, Argonne, 1979 p.385 [2] H.Kader et al., Phys. Uit. B227 (1989) 325 [3] L.Trache et al., Phys, Rev. C40 (1989) 1006 [4] M.Piiparinen et al., Z. Phys. A338 (1991) 417 Permanent addresses: 1 University of Jyvaskyla 2 Tokyo Institute of Technology 3 IKP Forschungszentrum, Jiilich 4 University of Granada 5 IFIC, Valencia 6 MSI, Stockholm Multiparticle- and particle x octupole states in 149Tb M.Lach, P.Kleinhein^, M.Piiparinen}j M.Ogawa3, Ś.Lunardi*, J.Styczeń, The 14"Tb nucleus has only three valence particles outside l4(5Gd, but dispite that one expects that its yrast spectrum will be quite complicated. This becomes apparent from in- spection of the neighbouring 148Gd high-spin excitations [1], where already at low energies the 146Gd core excitations contribute to the yrast configurations. In our experiments the high-spin states in 149Tb were populated in compound evaporation reactions with a- and 7Li-projectile8. We observed the levels up to 5 MeV excitation and / = 41/2^+\ The high sensitivity of the OSIRIS setup combined with the low angular momentum input of the ('Li,2n) reaction en- abled identification of levels above the yrast line. Our expe-imental findings are completed in the level scheme of Fig. 1. The 149Tb high-spin states are separated here into three groups corresponding to their nuclear structure properties. The most simple excitations are formed by three valence particles alone and are shown to the left. The middle column contains 149Tb levels which in addition involve excitation of low- lying 146Gd 3~ pbonon. The highest-spin levels to the right include higher-lying 146Gd proton particle-hole core excitations. These assignments are based on a shell model analysis where the level energies are calculated in the framework of angular momentum coupled inultiparticle configurations, including also the 3~ boson. The calculations are free of parameters since 93 TUT Ttv?«Ochjpole U/J1*1 KIT Figure 1: The 149Tb high-spin states observed in the present experiment. all dynamic quantities: particle-particle, partide-phonon matrix elements and 3ingle particle energies are taken from measured level energies in neighbouring nuclei. Shell model excitation energies calculated [2] for 149Tb are in quite excellent agreement with experiment- Among the three-nucleon configurations we could identify the aligned (i"ftn/2'//7/2t'ti3/2)31/2+ state at 3.142 MeV which uniquely specifies the so far unknown (ff/iii/a^is/a)^" attraction as -0.631 MeV. An interesting feature emerged from the irkn/2vh9i2v fop three body family, where the high-spin states resemble the symetry representations oi the S3 permutation group which was previously not observed in nuclei. References [1] M.Piiparinen et al., Z. Phys. A337 (1990) 387 [2] M.Lach et al., Z. Phys. A341 (1991) 25 Permanent addresses: 1 IKP Forschungszentrum, Jiilich 2 University of Jy vaskyla 3 Tokyo Institute of Technology 4 University of Padova 5 University of Granada 6 MSI, Stockholm 94 Collectivity in light Po isotopes 1 1 1 1 R.Alfier*, C.Bach , D.B.Fossan , Jl.Grawe , II.Khge ,_M1LachJ JULMąie/ 1 1 1 1 M^.Schramrn , R.Schubarl , M.Waring , JLJMJXIIHL, ILHubeP, Jing-ye Zhang The study of the very neutrondeficieut Po isotopes is interesting and important, since quite different structural features of nuclei are expected when going away from the closed N = 126 shell. The theoretical predictions suggest an increase of collectivity as N decreases which can be manifested as vibrations and further can lead to stable deformations. A specific enhancement of the octupole correlations is expected near N = 114 since the *i3/2 neutron orbit starts depleting there giving the possibility of (vfafiviia/i) particle-hole excitations. Such a contribution should create additional E3 matrix amplitudes and lower the energy of the 3~ octupole state. We have investigated 1G6Po and 198Po via (HI,xn) reactions using in-beam spectroscopy methods. The low-energy excitations in both nuclei deduced from, the present results are shown in Fig. 1. 203.11 111") 150m H91 1919 Figure 1: Excitations observed in the decay of the 7=11" isomer in 19QPo and 198Po. The comparison of both level schemes visualizes dramatic changes in the structure of 198 i93pc The gjiarp drop in the first 2+ł 4+ and 6+ levei8 reiative to those in Po implies an . abrupt increase in quadrupole collectivity at N — 112. It is also aparent from the 6+ — 8+ spacing which has increased to 549 keV in 106Po and cannot be described in terms of simple shell model couplings. Another important result of our experiments is the location of the second 2+ and 4+ levels in both Po isotopes. These states are interpreted as members of the expected collective band resulting from 4p2h proton pair excitations. The measured half life for the / = 11" isomer in 196Po gives the B(E3) value of 27(5) W.u. similar to B(E3) strength determined for 198Po. This E3 enhancement argues for octupole admixture in the I = 11" states and in turn implies low-lying collective 3~ states. Although theoretical considerations suggest the 3~ energies in the range of 1.2 -f 1.4 MeV, no such excitations were identified in our measurements. 1 HMI Berlin 2 SUNY Stony Brook 3 University of Bonn 95 Giant Dipole Resonance built on excited states of 55Mn W.Królas, P.Bednarczyk, B.Fonial, A.Maj, W.Mcczyński, J.Styczeń Giant Dipole Resonances (GDR) built on excited states of compound nuclei (CN) formed in heavy-ion collisions have been studied in a broad range of nuclei produced in different target- projectile combinations (see [1] and references therein). In most of this studies compound nuclei were formed at rather high excitation energy i.e. high nuclear temperature. This lead to inclusive measurements of high-energy gamma-rays depopulating GDR from all excitation steps in a decay of a compound nucleus. Consequently, the extracted properties of GDR were values averaged over a full excitation energy range. Few attempts have been made to restrict the observation to narrower excitation energy rauge using a differential technique [2] or selection of isomers [3]. A method leading to observation of gammas from the decay of GDR from mostly one deexdtation step is forming of the compound nucleus at low excitation energy. The excitation energy of the CN has to be high enough for enabling the build-up of the GDR, but has to be as low as to assure that after one particle evaporation there is almost no excitation energy left for further deexcitation via GDR decay. Such a method is especially suited for light and medium-light nuclei where the GDR energy is almost twice as big as the particle binding energies. In the experiment described in this note, a beam of a particles of rhe energy of 25.5 MeV from the Institute of Nuclear Physics cyclotron was used. The a particles bombarded a 2.4 mg/cm2 thick 51V target. A compound nucleus of-55Mn was formed at an excitation energy of 31 MeV with the mean angular momentum of 8 h. The emission of a high-energy gamma-ray from the decay of a GDR occurred mainly in the first step of the deexcitation, leaving the nucleus at the average excitation energy of about 8 MeV above the yrast line. If the deexcitation of the CN was initiated with the emission of a particle (a neutron or a proton), then the excitation energy- above the yrest line left for further deexcitation was of about 16 MeV, making the probability of emission of a gamma-ray of about 18 MeV smaller. Hence, the contribution from GDR decay at the second step was small. High-energy gamma-rays (£7 > 4 MeV) were detected in a 4" x 4" bismuth gemianate (BGO) detector placed 50 cm from the target. Two 2" x 2" Nal(Tl) scintillators were placed 15 cm from the target. Coincidence (beam burst, BGO and at least one of the Nal) and non-coincidence (beam burst and the BGO) gamma spectra were recorded. Both spectra are slrwn in fig. 1. The presence of GDR gamma-rays is seen as the broad bump at energies Ef > 11 MeV. The spectra presented in fig. 1 were fitted using the CASCADE code [4,5]. The free pa- rameters of the fitting procedure were the resonance energy (EGDR) and the width (FGD/J)- A one component resonance shape was assumed as for spherical nucleus or a nucleus with small deformation, which is a reasonable assumption for nuclei of mass A w 50 at low excitation en- ergies. The energy of the GDR obtained from the fit to the coincidence spectrum was smaller by about 1.5 MeV from the energy obtained form the fit to the non-coincidence spectrum. To understand this discrepancy, one has to consider that requhing coincidences between two counters we enhanced detection of events characterized by higher multiplicity (that means the events in which the CN was formed at a high spin). Because of the low excitation energy at which the CN was formed, and of quite steep slope of the yrast line in the nucleus discussed the selection of high-spin events lead to the yrast line cut-off effect of the high-energy part of the resonance. The GDR parameters (energy and width) as obtained from fits to the non-coincidence spectrum are = 10.5 ± 2.5 MeV 96 non-coincidence coincidence 107 106 r 105 iS 10* c c 8 8 io3 102 100 0 5 10 15 20 25 0 5 10 15 20x 25 gamma-ray energy [MeV] gamma-ray energy [MeV] Figure 1: The coincidence and non-coincidence gamma spectra from the investigated reaction. Solid lines are drawn for CASCADE code fits. They were found to be in good agreement with known systematics [1]. It is to be emphasized that the results given here refer to the Giant Dipole Resonance built on excited states of about 8 MeV excitation energy which corresponds to nuclear temperature of about 1 MeV. A crucial parameter for calculating gamma spectra in the statistical model approach is the level density parameter a. The CASCADE code assumes for excitation energy range Eexc > 20 MeV a simple dependence of this parameter on the mass of the nucleus a = A/S. The results presented here were obtained for values a = A/7 A, Fitting procedures using other paTametrizations gave non-physical results or proved to be divergent. Several authors propose to use different parametrizations of the level density parameter for nuclei of particular mass regions. For nuclei close to the system studied here (but at higher excitation energy) a = A/9.Q -r 9.5 dependence was suggested [6]. Hence, it was proposed to decrease the a parameter contrary to the results of this work. Our findings, however, are coherent with the level density parameters extracted [7] from measurements at very low excitation energy (mainly the measurements of the resonance spectra of slow neutrons), which show also that the parameters are very sensitive to shell-effects in the particular nucleus. The comparison of results presented here with those from ref. [6] suggests that the influence of the shell structure is not negligible even at temperatures T « 1 MeV. References [l] K.A.Snover, Ann. Rev. Nucl. Part. Sci. 36 (1986) 545 [2] J.J.Gaardh0je, A.Maj, Nucl. Phys. A52O (1990) 575c [3] A.Stolk, A.Balanda, M.N.Harakeh, W.H.A.Hesselink, J.Penninga, H.Rijneveld, Nuci Phys. A505 (1989) 241 W F.Piihlhofer, Nuci. Phys. A280 (1977) 267 [5] J.J.Gaardhflje, private communication [6] M.Kicińska-IIabior, K.A.Snover, C.A.Gossett, J.A.Behr, G.Fel'dman, H.K.Glatzel, J.H.Gundlach, E.F.Garman, Phys. Rev. C36 (1987) 612 m A.Bohr, B.R. Mottelson, Nuclear Structure, W.A.Benjamin, Inc., 1969 , vol. 1, p. 187 97 New 157Lu isomer M.Lcwandowskii, AJV..J}oicmpa,x\V.I.Fominikh2yK. Ya.Gromov2, MJanickij- Ju. V.Juschktvich2, 'V~G-Ka\innikov'1, N.-Ju.Kotovskij2, V.V.Kuznelsov?; N.Raschkova2, Ja.A.Sajdimov2, and J:Wawryszcxukl The identification of the proton single particle /in/2 and «i/2 isomeric states in Z = 65, 67, 69 and N =r 82, 84, 86 nuclei I1' allows the existence of analogous states in the ^Lugo nucleus. We searched for these isomcrs at the YASNAPP-2 ISOL facility P) located at the external proton beam of the JINR phasotron accelerator. A = 157 ions from tungsten target irradiated by a 660 MeV proton beam were separated and collected for 16 s on an Al substrate. The alpha-spectra of each radioactive sample were measured 12 times for 56 s. A new alpha-line with EQ = 4925(5) kcV and T1/2 = 9.6(8) 8 was observed in the alpha-spectra (Fig. 1) together with the ealier know lines t3'4' from the decays of 187Lu 157 153in 153 153 (T,/a = 4.8 s), Yb (37 s) and their daughter products Tm (1.7 s), »Tm (2.5 s) and Er (36 s). 1000- *wTtn oompWx a -lla« Isobar doufala oosptmML fU. A=L57 ^|/2-*-7*(")» T -0.7(12)* •spectrum * l/a I | tOO •: ^^ "••"Lua-Unt U 10 "3 5 : 2 1 tli I I I I 3200 3300 3400 3500 3800 0 16 34 33 40 ES Channel Ttmo (»] Fig. 1. Sum alpha-particle spectrum af mass separated Fig.2. The decays of the doubh alpha-Une ol '"•"•» Tm iso- A=157 activities produced with 660 MeV protons on a mera (upper cuive) and of alpha-lines of •""••» Lu isomers in W target measured for 56 s after 16 8 collection time. an A=157 isobar -ource. Values of Ti/a correspond to the best least squares fit. The observed intensity-time dependence (Fig. 2) for unresolved alpha-lines 5099 keVand 5106 keV from the decays of 153m'»Tm isomers allow us to conclude that the new line belongs to the 157Lu decay. There are also other arguments for such identyfication: a) the new line is as wide as the aipha-line of 157Yb contrary to the lines of the daughter nuclei, which are about 30% wider under our experimental conditions; b) Hf and Ta ions in the surface ionisation ion source used are not produced; c) alpha-decay energies for 157Tm and 157Er are much less than 4925 keV according to Wapstra'a predictions '53; * • ' d) an isomeric state in 157Yb is not expected. 157 Thus the nucleus Lu has two isomeric alpha-decaying isomeric states with Ti/2 = 4.8 s and 9.6 s. The exponential decrease of both 4925 keV and 4998 keV alpha-lines of 157Lu proves that there is not a strong gamma-transition between these isomeric states. 153 From the centroid shift (Fig. 3) of the Ea = 5106 keV double alpha-line of the Tm isomers decay one can see that the component with a larger energy and intensity (T^ = 1.5 s) follows the decayvof the 98 l57 lu isomer with Ti/2 = 4.75 s and E« =4998 keV. Energy difference between the two components of the complex alpha-line of 153m'"Tm obtained with the help of centroid shift analysis is AE = 10(3) keV (Fig. 3) in agreement with 7(4) keV value from paper '61. 8- ^^ ^S.7(12)s h + 1.7j 1/2+ (l/2 ) U & ) 2.5s H/2" o- I53Tm Fig.4. The hu/a and si/a isomLric states In 18TLu. Fig.3. The centroid shift of the double alpha-line of '" Lu isomcra as Ł function of time. Below there is the some depem?".n- ce for a single alpha-line of •»' Yb. Encircles is the structure of the complex alpha-line or "» Tm. 153 6>7 159 Now taking into considration the data on isomeric s1/2 and hn/y states in Tm I 1 and Ho M l57 we can conclude that the 11/2 isomer in Lu with Ti/2 = 4.75 s lies 32(2) keV above the new low spin state with Ti/2 = 9.6 s (Fig. 4). The si/2 isomeric state is the ground one in i47,i49.iBi>rjj nucy ^^ ^ excited one in "o,isi,i53Ho and 153,15^,^ naciei One can be surprised that in ^jLu this low spin prooably 81/2 state is agair. lower than the hu/2 one. This fact may be related to the observed increase in the pairing energy with the atomic number in this area of rare earth nuclei W, Bx-erpt from Z. Phya. VI340 (1991) 107 M.Curie—Skłodowska University, Lublin, Poland Joint Institute for Nuclear Research, Dubna USSR References [1] A.W.Potempa et a]., hv. AN SSSR, ser. phys., 54 (1990) 852 [2] V.G.Kalinnikov et al., JINR, D13-90-183 (1990), Dubna [3] E.Ye.Berlovich et al., Ada Phya. Polonica B10 (1979) 857 [4] K.S.Toth et al., Phys. Rev. C27 (1983) 889 [5] A.H.Wapstra, G.Audi, R.Hoekstra, ADNDT 39 (1988) 281 [6] D.Schardt et al., Proc: 5t.li In*. Conf. Nuclei far from Stability, Rosseau Lake, Canada, N.Y., 1987, p.477 [7] R.B.Firestone et al., Phya. Rev. C39 (1989) 219 [8] M.O.Kortelahti et al, Phys. Rev. C39 (1989) 636 [9] G.D.Alkhazov, K.A.Mezilev et al., Z. Phys. A311 (1983) 245 99 9 Generalized Cross Section Scaling for K-Shell REC Th. Stöklker1, E.M. Bernstein2, L. Cocke3, H. Geissel1, C. Kozhuharov1, P.H. Mokier1, R. M'îshammer1, G. Münzenberg1, F. Nickel1, P. Ryimiza*'1, Ch. Scheidenberger1, Z. Staclmra, J.Ullrich1, A. Warczak4 1 GSI Darmstadt, Germany; 2 Kalamazoo, MI, USA; 3 Manhattan, KS, USA; Ą Jagiellonian University, Cracow * on leave from Institute of Nuclear Problems, Świerk Radiative Electron Capture (REC) is a recombination process in which a highly charged ion captures a target electron and emits a photon. For bare and II tike projectiles capture into the K-shell gives the dominant REC contribution. A detailed knowledge of this process is important for a description of electron capture in fast heavy ion atom collisions, formodelling of electron cooling processes in storage rings, and for estimation of lifetimes of highly charged ions in storage rings. Very recently, the application of REC for structure studies of heavy, few electron ions has been proposed as well [1]. We show in Fig. 1 that all measured K-REC cross sections given in the literature, nor- malized to the number of K-sheil vacancies and per target electron, can be compared within E tN a generalized picture by introducing an adiabaticity parameter n with t] = g (EKIN the kinetic energy of the electron in the projectile frame, and EK the K-shell binding energy) [2], For the gas target measurements the systematic uncertainties are shown by the error bars in Fig. 1. The statistical uncertainties are smaller or comparable with the size of experimental data points. For the solid target experiments the overall uncertainty is shown by error bars according to the original papers. Within the uncertainty limits one observes in Fig. 1 very good agreement between measured and calculated cross sections (see full line in Fig. 1). How- ever, most of the data seem to fall slightly below the theoretical curve. We like to point out that the data shown in Fig. 1 represent measurements for REC into projectiles from fluorine up to uranium with adiabaticity parameters »y ranging from 0.2 up to 3. The adiabaticity parameter can be used in order to scale the cross sections to one common curve which is well described by the dipole approximation [3] (see full line in Fig. 1). Therefore, Fig. 1 can be used to get reliable K-REC cross section predictions for all collision systems at adiabaticy parameters between 0.2 and 3. In addition, first preliminary results for K-REC into Bi82+ ions measured during the beam time at the FRS facility (GSI, Darmstadt) in December are plotted (see full points in Fig. 1). Here, only x-rays seen by one segment of one fivefold Ge(i) detector have been analyzed in coincidence with projectiles having captured one electron, see Ref. [4]. These data seem to manifest the tendency that the calculated cross sections slightly overestimate the experimental results. A final data evaluation of the Bi experiment will improve the accuracy of the data and can therefore test the theory with a high precision in the discussed 77 regime. However, for large rj-values only few experimental data are available. Therefore, it would be desirable to investigate this ^-region for heavy, bare or hydrogenic ions at corresponding energies under single-collision conditions. Here, relativistic effects can be studied. 100 9 Bi -» C • F -> He <3 Ca -> He A Ge -* H2 A Ge -• H2 0 Xe -+ Channeling in Si • U -> Mylar O.I 1 Adiabaticity Parameter t\ Figure 1. Total cross sections for K-REC per projectile K-vacancy and per target electron vs adiabaticity TJ for different collisions systems. A prediction using the dipole approximation [3] is given by the solid line. References [1] P.H. Mokler et al., Z. Phys. D21 (1991) 197 [2] Th. Stohlker et al., preprint GSI-91-67, Z. Phys. D (in print) [3] M. Stobbe, Ann. d. Physik 7 (1930) 661 [4] Th. Stohlker et al., contribution to this report 101 Electron Capture Studies for Highly Charged Bi-Ions at the FRS-Facility (GSI, Darmstadt) •Thv StoMker±, HrGeissel1,3£=-H. Behr\-fr.:MLBernstein2, ^-Kr Burkard1,^. Cocke3, Or-Kozhuliarov-j-PvH.-Mokler-1, - R. Moshammer1; G. Miinzenberg1-, F. Nickel1, P. Rymuza*-1, i~ Seheidenberger-, Z. Stacnura, X-lUldUfh1, A. Warczak4 1 GSI Darmstadt, Germany;7' Kalainazoo, MI, USA;3 Manhattan, KS, USA; 4 Jagiellonian University, Cracow * on leave from Institute of Nuclear Problems, Świerk During a beam time at the FRS in December, non-resonant electron capture processes into very heavy projectiles were studied for the first time state selectively via coincident registration of projectile x-rays with the charge changed projectiles (Proposal #S085). In this experiment a new operation mode of the FRS was successfully tested allowing to measure separately the x-ray emission of projectiles associated with captu e, excitation, and electron loss [11. Ill 1 • Stripper Collim. SIS> Bi' Energy Charge [HeV/u] q 82,119,168 83.82.81 Figure 1: F/xperimental arrangement for x-ray/particle coin-idence measurements at the FRS. For non-resonant electron capture one has to consider two comp Jting capture mechanisms, the Radiative Electron Capture (R.EC) and the kinematic or Non-Radiative Electron Capture (NRC). Due to their different cross section dependencies on target atomic number Z? (CTREC ~ ZT, &NRC ~ '^T)I on the projectile charge state q, and on the collision, energy, these processes were studied at different projectile energies with three solid targets and initial projectile charge states of 83+, 82+, 81+. Thus, by changing the target — we had C (0.55 mg/cm2), A1 (0.49 mg/cm2), and Nl (0.13 mg/cm2) — we can tune to the capture of bound electrons (Ni-target) or of quasi-free electrons (C-target). Moreover, we chose our projectile energies at the target outside the resonant electron capture (RTE): 82 MeV/u — just below the KLL resonances, 119 MeV/u — beyond the KLL resonances, however, below the KLM resonances, and 168 MeV/u — beyond the series limit of all KLn (n = oo) resonances. Hence, depending on the target we only investigated REC or NRC alone. For this experiment, Bi-ions accelerated in 102 the ,SJS worp .stripped in foils to high charge states after entering the FR.S. Thereafter, B2ł the first stage of the FRS (SI) was used to 82 MeV/u Bi -> select one defined charge state which was focused with the second stato of the FRS (S2) on the x-ray production targets, see Fig. i. Behind the target area the beam was charge state analysed in the stages 3 and 4 of the FRS. The exact beam ge- ometry could be checked with x,y posi- tion sensitive rnultiwire chambers (see full points in Fig. 1), in particular in the vicin- ity of the target and at the end o[ the beam line. Here, three plastic scintilla- tora were mounted outside the vacuum in order to detect projectiles with the pri- mary charge state and projectiles having captured or lost one electron. The target area was viewed by two granular Ge(i) x- ray detectors each with a total active area of 275 nirn2, one mounted close to the tar- get, giving a large solid angle and the other one more distantly in order to reduce the Doppler broadening jf the x-ray lines. As an example, the x-ray spectra for 82 MeV/u Bi82+ ions on C and Ni targets 50 70 80 90 100 no i2o no uo measured in coincidence with projectiles X-Ray Energy (KeV) having captured one electron are plot- ted. For the C-target we see a promi- Figure 2. Coincident x-ray spectra for nent K-REC line as well as clearly sepa- 82+ rated L,M,N-REC contributions which fi- 82 Me.V/u Bi -• C (top) and for nally cause by deexcitation the character- the Ni-target (bottom) associated with one electron capture. istic Kradiation K«i, Ka2, K/3, K7, ... . (First preliminary K-REC cross sections extracted from this measurement are given in this report, too [2].) For the Ni target, the REC is suppressed and only x-ray radiation caused by NRC into excited levels can be observed. We like to emphasize that the coincident x-ray spectra are absolutely baclcgrouud-free and, therefore, can also be exploited for a precise spectroscopy of the structure of one and two electron Bi-ions [3]. References [1] A. Magel et al., GSI Scientific Report, GSI-92-1 [2] Th. Stohllcer et al., contribution to this report and GSI Scientific Report, GSI-92-1 [3] P.H. Mokkr et al., GS1 Scientific Report, GSI-92-1 103 Spectroscopy Studies of Groimdstate Transition in H- and He-like Bi Ions -RIL-Makfer1 ,-Th. Stoldker1, E.M, Bernstein2, L. Co eke3, H. GeisselV Gr-Kozhtrharov1; Rr Moshammer1, G. Miinzenberg^, -F.-Nkkel VFH3ymTraa*jlr^hr-SeJi-eidenberger1, ZrStachura, , AvWarczak4 1 GSIDarmstadt, Germany;7 Ka.lama.zoo, Ml, USA;3 Manhattan, KS, USA; 1 Jagiellonian University, Cracow * on leave from Institute of Nuclear Problems, Świerk For the state selective investigation of electron capture processes during a beam time at the FRS in December, the x-ray particle coincidence technique was applied [1]. Here, the projectile x-rays were registered by 10 independent Ge(i) x-ray detectors in coincidence with fast scintillator counters detecting projectiles with the primary charge states q (electron excitation), q — 1 (electron capture), and q -f 1 (electron loss). The coincident x-ray spectra are absolutely background-free and are exploited for a precise spectroscopy of the structure of H-and He-like Bi projectiles. As an example we show in Fig. 1 coincident x-ray spectra of one detector segment blown- up around the Ka region for incoming 82 MeV/u bydrogenic Bi(82+) ions hitting a C (0.55 mg/cm2) target. In the lower spectrum coincidences with the primary charge 82-t- have been selected; i.e. we see the pure excitation in hydrogenic Bi(82+) ions, the Lyman a lines. In the upper spectrum the coincidences are switched to one electron capture events; i.e., we see the Ka-lines of the He-like Bi(81+) ions. For clarity we show in Fig. 1 also the x-ray decay modes for each case. 1 Experiment Theory II Lyaj : 8C1.188 .100 Z 80.143 ± P3/2 [2] Bi82+ Lya : 77 393 .100 2 77.337 2 ± P1/2 2 77.379 s1/2 Kfti: 78 825 ± .100 78.860 131 3 78.797 P2 Bi81 + 3 Ka2: 76 085 ± .100 P. 76.127 3Po 75.995 Table 1: Transition energies (keV) in H- and He-like Bi-ions. In the table, the corresponding theoretical transition energies [2, 3] are compared with our measured centroid energies. As experimental error we assume three times the statistical error for an inclusion of systematic errors. We like to point out that the spectra shown refer only 104 to the data of one .segment of one fivefold x-ray detector. The data evaluation also for other energies and targets is still in progress enabling us in the end to extract by far more precise values than given in (lie table. However, already now the total error is a factor of about 3 smaller than the ground state Lamb shift (260 eV [2|) in hydrogenic Bi. From the good agreement of the measured and theoretical values in the table we can state a good validity of the calculations for very heavy ions. In order to further improve our x-ray particle coincidence method a special Ge(i) x-ray detector with parallel strip areas will be available soon. This detector adjusted to a geometry at the ESR will allow a good x-ray energy determination. Additionally, applying to this de- tector appropriate soller slits lifetime measurements for heavy projectiles seems to be feasible. Corresponding spectroscopy experiments are in preparation. Bi Bi82+ 70 71 72 73 7ł 75 76 77 79 79 X-RAY ENERGY (KeV) Figure 1: Coincident x-ray spectra for 82 MeV/u Bi82+ on C collisions. The Ka-radiation region is shown. The spectrum at the top is associated with capture events and shows the transitions in the He-like system indicated by the corresponding level diagram. The bottom spectrum is associated with no charge changing events, i.e. excitation events, and shows the H-like system. In addition, the fit to the data points is shown. References [I] Th. Stohllcer et al., contribution to this report [2] W.R. Johnson, G. Soft, ADANDT 33 (1985) 405 [3] G.W.F. Drake, Can. J. Phys. 66 (1988) 586 105 Hypernne interaction of mCd in Pd-In intermetallic compounds P. Wodniecki, B.Wodniecka, M.Marszałek, A.Z.IIrynkiewicz A large compilation of the results obtained on the nuclear quadrupole interaction in various compounds was recently published by Lerf and Butz [1]. Our measurements for In-Pd system enlarge the limited data range for intermetallic compounds. Bulk samples of In:Pd atomic ratios corresponding to InaPd, In3Pd2 and InPda were melted in argon atmosphere. The carrier free solution of ulIn in 0.01 M HC1 was earlier dried- out on the Pd-foil in order to dope the investigated specimens with the In parent isotope. After the 24 hour annealing of the samples at 750 K the PAC spectra were taken using the 4-NaI-detector setup. P(fQ) 100 ZOO 200 400 600 800 tfns] I/Q[MHZ] Figure 1: PAC spectra with Fourier transforms for mIn-doped In-Pd compounds. The analysis of all experimental PAC R(t) spectra, directly related to the perturbation factor G2(t), has been performed assuming the following expression: (1) »'=1 n=0 The least squares fits of the perturbation factor to the experimental data yield the fractions f,- of probe atoms exposed to difFerent electric field gradients (EFG) corresponding to frequencies 106 UQi and asymmetry parameters T/,\ These parameters were used to determine the different structures around the probo atoms. Since the parent of inCd is an indium isotope, one may assume that inCd occupies tli<; regular lattice sites of iiulium atoms in all of I»-Pd compounds. Fig. 1 shows the PAC time spectra and the corresponding Fourier transforms for the investigated In-Pd compounds. Unique quadrupole frequencies found in all three R(t) functions indicate the ordered structure of our samples. The numbers of observed frequencies, two for In3Pda and Iu3Pd and one for InPd2, reflect the numbers of nonequivalent indium sites given by the corresponding crystal- lographic structure (table 1). The measured relative fractions U of the observed frequencies reproduce the populations of both sites, and the calculated (point charge model) asymmetry parameters 77 for all three structures are in agreement with the fitted 77 values. Table 1: The structural data and quadrupole interaction parameters in In-Pd compounds. Compound Structure In-site no[MIIz] In3Pd In^Ge? 16 In(f) 58.3(2) 0 D8/ 12 In(dj 281.7(5) 0 In3Pd2 Ni2Al3 2 In(d) 162.2(3) 0 D513 1 In(a) 256.2(5) 0 InPd2 Ni2Si 4 In(c) 57.7(3) 0.36(2) C37 The temperature dependence of quadrupole frequencies measured in a number of metallic systems can be explained in terms of a major contribution arising from a change in the mean- square displacement due to lattice vibrations [2,3]. It is experimentally well established that in most metals and metallic systems this dependence follows a T3/2 law: The temperature measurements for In3Pd, I«3Pd2 and InPd2 compounds were performed in the temperature range of 80 K - 873 K. The results of least-squares fits of equation (2) to the experimental data are presented in table 2. In some cases (marked with asterisks in table 2.) better fits were obtained assuming a linear temperature dependence. The measurements around liquid helium temperature could be decisive for the determination of the I'Q(T) shape. 3/2 Table 2: The fitted parameters I/Q(0) and the slope b of the T relation. 5 3 2 Compound gQ(0)[MHz) b[10- K- / ] In3Pd 59.2(2)* 0.29(3) 288.0(4) 0.43(1) In3Pd2 165.5(4) 0.42(2) 261.1(3 0.37(3) tr. r.'t InPd2 0.41(3) References [1] A.Lerf and T.Butz, Hyp. Int. 36 (1987) 275 [2] P.Jena, Phy$. Rev, Lett. 36 (1976) 418 [3] K.Nishiyania, F.Dimmling and D.Riegel, Phys. Rev. Lett 37 (1976) 357 107 Intermetallic compound formation at In-Pd interface investigated with mIn local probes P.Wodniecki, M.Marszałek, B.Wodniecka, A.Z.Hrynkiewicz Interdiffusion of atoms at the metal-metal interface leading to the formation of inter- metallic compounds is extensively investigated because of its great fundamental and practical importance. Among the numerous methods applied in that field the PAC technique is very suitable due to the high microscopic sensitivity to the local structure variations. Previous PAC studies in the Cu/In, Ag/In, Au/In and Ni/In [1,2,3] systems have shown the formation of interface compounds resulting from thermally induced interdiffusion. . Here we report on the formation of Pd-In compounds in bilayer samples. Indium layer (3.2 fim thick) was electrodeposited from I11CI3 solution doped with radioactive mIn onto the 4.6 fim thick palladium foil. The PAC spectrum recorded directly after the In deposition reveals only the well known hyperfine interaction of probe in tetragonal In. Subsequent isochronal (30 min) sample annealings at increasing temperatures caused the Pd diffusion into the In layer reflected in the R(t) curves. New unique quadrupole frequencies have appeared which indicate the formation of ordered phases in the sample. A typical PAC spectrum after annealing at 350°C is presented in fig. 1 together with the Fourier transform of the data where the fitted quadrupole frequencies related to h^Pd and In'3Pd2 formation are indicated. [MHz] Figure 1: R(t) function and the corresponding Fourier transform for In/Pd bilayer annealed 30 min at 350° C. The identification of the In-Pd compounds thus formed was based on the PAC measure- ments for bulk In-Pd samples with defined stoichiometry [4]. In fig. 2 the fractions of probe atoms in different environments are shown versus annealing temperature. The subsequent formation of three In-Pd compounds (I^Pd, InaPdj, InPdj) with increasing Pd contents is seen with the rise of annealing temperature. The remaining two compounds known from the phase diagram are difficult to detect because of their crystallographic structure, since no characteristic unique frequencies can be observed in the cubic InPd (B2, CsCI type) or in the disordered InPd3 compound. 108 Pd(4.6/im)/ln(3.2/im) (Pd/I»),t = 2.5 100 In InaPd In3Pd2 lnPd2 C 00 o fin 3 60 40 20 0 0 100 200 300 -100 500 600 700 Annealing temperature [*C] Figure 2: Evolation of the ulIn fractions in dirTeront surroundings with annealing tempera- ture. References [1] W.Keppner, R.Wesche, T.Klas, J.Voigt and G.Schatz, Thin Solid Films 143 (1986) 201 [2] P.Wodniecki, B.Wodniecka, M.Marszalek, Z.Mazgaj and B.Kubica, Hyp. Int. 60 (1990) 841 [3] R.Platzer, U.Wohrmann, X.L.Ding, R.Fink, G.Krausch, J.Voigt, R.\Vesch« and G.Schatz, Hyp. Int. 60 (19dO) 1003 [4] P.Wodniecki, B.Wodnierka, M.Marszalek and A.Z.Hrynk'iewicz, this trport 109 PAC measurements of In-Pt intermetallic compounds M.Marszałek, B.Wodniecka, P.Wodniecki, A.Z.Hrynkievncz Investigations of the electric field gradient (EFG) provide important information about the electronic structure in the neighbourhood of the probe nuclei. Although extensive data is now available on the quadrupole interaction at probe atoms in pure metals [1], only a few investigations of the quadrupole interaction in intermetrJlic compounds have been carried out to date [2]. In this paper we report on the application of the perturbed angular correlation (PAC) method to the study of the In-Pt system. The indium-platinum bulk samples were prepared by melting in argon atmosphere the appropriate amounts of the constituents doped with carrier free lllIn. In order to ensure sample homogeneity the 24 hour annealing was performed at 773 K for each sample. The quadrupole interaction at the site of indium atoms was measured by observing the time dependent perturbed angular correlation of the 173-245 keV 7- 7 cascade through the intermediate 5/2 level in nlCd. Delayed coincidences were recorded at different temperatures (77 K - 700 K) with a conventional fast-slow four detector system. From these measurements the perturbation factor 0^(1) was obtained and fitted by the appropriate theoretical function [3], describing the quadrupole interaction in polycrystalline sample. The values of quadrupole interaction frequencies UQ = eQVzzJh and the asymmetry parameter 77 extracted from the fitting procedure are collected in table 1. Table 1: Tho crystallographic data and quadrupole interaction parameters. Compound Structure In-site i/glMHz] V In7Pt3 Ir3Ge7 16 In(f) 91.5(3) 0 D8j_ 12 In(d) 316.4(5) 0 In3Pt2 Ni2Al3 2 In(d) 177.4(3) 0 276.8(4) 0 D5,3 1 In(a) For each compound two different EFG's were measured reflecting the existence of two nonequivalent indium sites according to the crystallographic data [4]. The observed inCd relative fractions reproduce the populations of these sites (table 1). Point charge model calculations, performed using the lattice parameters reported in [4], result in an asymmetry parameter 7/ = 0 in agieement with our measurements. Typical spectra measured at room .temperature together with Fourier transforms of the data are shown in fig. 1; the quadrupole frequencies obtained from the fitting procedure are indicated in the Fourier spectra. For metals and intennetallic compounds (except the C16 compounds) the electric field gradient generally decreases with the three-halves power of the temperature-: We used this formula to fit the EFG temperature dependence of In-Pt compounds. The results are shown in table 2. Following the In-Pt phase diagram we have also performed the measurements for differ- ent In-Pt compounds with platinum atomic concentration above 40 %. In the concentration range (40 - 75 ) at.% of Pt this system has at least five compounds of either cubic or very 110 0.1 o.o. 100 200 0 zoo 400 eoo ooo t[ns] I/Q [MHz] Figure 1: PAC sper.tra for In/Pt3 and with the corresponding Fourier transforms Table 2: The fitted parameters of UQ(T) temperature dependence. Compound *>o(0)[MHz] b[10-5K-3/2] Ir.7Pt3 92.7(1) 0.22(1) 321.8(3) 0.33(1) In3Pt2 179.9(3) 0.26(1) 280.9(5) 0.26(1) complicated structure, with a variety of indium sites. Therefore, it was not possible to extract the EFG parameters from the mersured PAC patterns. The quadrupole interaction parame- ters measured for In7Pt3 and Iii3Pt2 'ntermetallic compounds correlate very well with those for their isostructnral partners in In-Pd [6] and In-Ni [7] systems. References [1] ILIIaas and D.A.Shirley, J. Chem. Phys. 58 (1973) 3339 [2] S.A.Lis, ILA.Naumann and G.Schmidt, Hyp. Int. 3 (1976) 445 [3] H.Erauenfelder and R.M.Steffen, Perturbed Angular Correlations, eds. K.Karls- son, E.Mathias and K.Siegbahn, North-Holland, Amsterdam, 1963 [4] S.Heinrich and K.Schubert, J. Less-Common Met. 57 (1978) PI [5] E.N.Kaufmann and It.J.Vianden, Rev. Mod. Phys. 51 (1979) 61 [6] P.Wodniecki, B.Wodniecka, M.Marszalek and A.Z.Hrynkiewicz, this report [7] R.Platzer, U.Wolirmann, X.L.Ding, R.Fink, G.Krausch, J.Voigt, R.Wesclie and CSchatz, Eyp.Int. 60 (1991) 111 The study of compound formation in In/Pt system M.Marszałek, B.Wodniecka, P.Wodniecki, A.Z.Hrynkiewicz Recently much attention has been dedicated to the investigation of diffusion near and at the metal-metal interfaces with respect to the technical applications, for instance in micro- electronic devices [1]. Investigations of hyperfine interactions provide important information about this phenomena via detection of electric field gradients (EFG) at radioactive probe nuclei characterizing the change of system properties at interfaces. Here we report on the application of the perturbed angular correlation (PAC) method to study the formation of interface compounds in the In/Pt system. The indium-platinum bilayers were prepared by electrodeposition of indium from InCb solution doped with ra- dioactive niIn on the platinum foil. The samples were subsequently annealed for 30 minutes within a temperature range from 300 K to 1073 K. After each annealing step the PAC spectra were recorded at room temperature. The measurements were performed with a conventional fast-slow coincidence setup with four detectors. In 500 1000 VQ[MHZ] Figure 1: The Fourier transformed PAC spectra for In/Pt bilayer versus annealing tempera- ture. The Fourier transformed PAC spectra taken during isochronal annealing program are 112 presented in lig. 1. The standard formula for the (|iiadiupole interaction in polycrystalline sample [2] was used for fitting the experimental R(t) function. As a result the EFG parameters and the values of probe fractions f,- in different environments were obtained. The electric field gradient is measured al ulCd, whereas the actual position of the probe atoms is determined by the location of the parent lnIn chemically identical with one of the bilayer constituents. The annealing behaviour of the observed H1Cd fractions is shown in fig. 2. 3/tm)/ln(4 7fj.m) n)„i= 1.93 Iri?P In Pl rr 100 a a a 80 o 60 u. 40 •»- 20 /}*~e"- — •i 0 100 200 300 400 000 600 700 800 Annealing temperature [°C] Figure 2: Fractions of inCd probe atoms experiencing well-defined EFG 1s as a function of annealing temperature for In/Pt bilayer. With increasing annealing temperature the fraction of probes in pure indium f/n decreases and the successive formation of In-Pt compounds as a result of interdiffusion at elevated temperatures is observed. Basing on our PAC measurements for the bulk Pt-In compounds b [3] the creation of In7Pt.3 (f \' ) and In3Pt2 (f \' ) was evidenced in bilayer sample. The interpretation of the PAC spectra taken after annealings above 600"C is very difficult because of their complexity. The superposition of many quadrupole frequencies observed in those spectra related to the possible formation of various InPt compounds makes their quantitative analysis impossible. The compounds built al the interface in Pt/In bilayer occur in the sequence running through the phase diagram from the In-rich to the Pt-rich side. In the In/Ni [4] and In/Pd [5] bilayers the analogical behaviour was observed. Thus it can be concluded that the formation of the interface compounds in these systems is caused by diffusion of Pt, Pd and Ni into In. References [1] W.Keppner, R.Wesche, T.KIas, J.Voigt and G.Schatz, Thin Sol. Films 143 (1986) 201 [2] H.Frauenfelder and R.M.Steffen, Perturbed Angular Correlations, eds. K.Karls- son, E.Mathias and K.Siegbahn, North-Holland, Amsterdam, 1963 [3] M.Marszałek, B.Wodniecka, P.Wodnierki, A.Z.Hrynkicwicz, this report [4] R.Platzer, U.Wohrmann, X.L.Ding, R.Flnk, G.Krausch, J.Voigt, R.Wesche and G.Schatz, Hyp.Int. 60 (1991) 1003 [5] P.Wodniecki, M.Marszalek, U.Wodnierka, A.Z.Hrynkiowicz, this report 113 PAC studies of Agln2 and Ag2ln growth kinetics at Ag-In interface B.Wodniecka, P.Wodniecki, A.Z.Hrynkiewkz Owing to a short-range character of the electric field gradient the PAC technique offers a high microscopic sensitivity to local structure variations and is therefore very suitable for studies of compound formation at interfaces. Thin Agin film at room temperature was first investigated by Simić and Marincovic [1] in X-ray diffraction experiment. They reported predominant Agln2 formation followed by the formation of Agjln via the reaction of Aglnj with surplus silver. The thermal behaviour of thin Ag/In evaporated bilayers was studied by Keppner et al. by PAC [2] at low temperatures and the Aglri2 formation was observed. Isother- mal annealing experiments at 220 K - 280 K yielded a square root of time dependence for the average compound thickness, supporting the assumption of a diffusion-controlled growth mechanism. In OUT previous work [3] the isochronal annealing studies of electrodeposited Ag/In layers at elevated temperatures were performed and the formation of Ag2ln besides the Agln2 was evidenced. Here we Teport the results of an isothermal annealing program at the temperatures 300 K - 423 K. Several samples with various atomic ratios of Ag:In (0.5 -f- 2.5) were prepared by electroplating of In homogeneously doped with radioactive niIn on Ag foils from I11CI3 solu- tion. After each annealing step the PAC spectrum was recorded at 80 K. The representative spectrum is plotted in fig. 1 together with Fourier transform of the data where the quadrupole frequencies obtained from the fit are indicated. -O.O4 0 IM 100 100 JM 0 100 200 30C KO Figure 1: PAC spectrum recorded at 80 K and its Fourier transform for the m In( In)(17 /u)/Ag(25.5 /*) sample after 8.5 hour annealing at Tann = 423 K. The results of the experiment are shown in fig. 2, where the average thickness of interface compounds calculated from the fitted values of lnIn fractions is presented as a function of annealing time at constant temperature. Based on the crystalline structure and lattice 3 3 constants [4] a density of 8.43 g/cm [2] for Agln2 and of 9.78 g/cm for Ag2ln was assumed for thickness calibration. The dotted lines in fig. 2 for Tann = 300, 373, and 400 K represent the values of the Agln2 thickness calculated as: 5 1 adopting the values of Do = 4(3) x 10~ ernes' and Ea = 0.46(3) eV [2]. For room tem- l 2 perature annealings a linear relationship of Agln2 average thickness versus t t Is seen in accordance with [2] giving the value of the diffusion rate D — 5.3(1) x 10~13cm2s~1. However 114 6000 d [nm] •4000 2000 1S0O0 10000 y' 5000 > Tonn « 423 K 0 1 2 3 + 0 W)' Figure 2: Average thickness of Agln2 (full circles) and Ag2ln (open circles) interface com- pounds as a function off1''2 during an isothermal annealing program at various temperatures V J-ann- this is no longer true for higher annealing temperatures. Some effect of saturation can be seen at Tann — 373 K and 400 K although no Ag2ln is still observed in contradiction to the X-ray experiment of Simić et al. [1]. Firstly at 423 K the Ag2ln fraction is visible and its average thickness versus f1/2 shows the linear dependence giving the fitted value of the diffusion rate D = 4.6(3) X 10"n em's"1. The interface compound growth at higher temperatures must be regarded as the superposition of several possible difFusion processes taking place during the compound formation. References [1] V.Simic and Z.Marincovic, Thin Solid Films 61 (1979) 149 [2] W.Keppner, R.Wesche, T.KIas, J.Voigt and G.Schatz, Thin Solid Films 143 (1986) 201 [3] P.Wodniecki, B.Wodniecka, M.Marszalek, Z.Mazgaj and B.Kubica, Hyp. Int. 60 (1990) 841 [4] Landolt-Bornstein, Slrukturdaten der Elemente und intermetallischen Phasen, Springer-Verlag, 1971 115 mCd quadrupole interaction in 7- brass intermetallic compounds B.Wodniecka, P.Wodniecki, M.Marszałek, A.Z.Hrynkiewicz Gamma brasses are electron compounds with metallic bonding based on compositions at which the electron to atom ratio is 21/13 . There are three closely related types of structure D81, D2>i and D83. Each one is cubic and contains 52 atoms per unit cell. They exist over appreciable homogeneity range. Prototypes of those throe types are Fe3Zni0, CusZn8 and CU9AI4. In this work we report preliminary results of the PAC measurements for CujZns, AgsZns, C119AI4 and Ag2ln 7 -brasses. The samples were prepared by melting proper amounts of components under the Ar atmosphere. The niIn parent activity was introduced either by adding the carrier free luIn during melting or, in the case of Ag-compounds, by a-irradiation of the silver before melting. The structure of the samples was checked by X-ray measurements. All PAC spectra were recorded at room temperature. 0.0 [MHz] Figure 1: PAC time spectra and corresponding Fourier transforms. 116 The fitted 1]1Cd quadrupole interaction parameters UQ and 77 are collected in table 1. In order to determine the probe position, the lattice sum calculations based on the point charge model wore performed. The obtained 77"1 values are given in table I. For all the compounds except CU9AI4 two quadrupole frequencies were observed in accordance with two possible probe locations. In CusZns and Ag5Zns the probe atoms most probably occupy the Zn-site. For CU9AI4 only one probe site is populated and its location is still a question. In the case of the Ag2ln brass it was not possible to decide whether it has D82 or D83 structure, though the observed ratio of two probe fractions suggests the D83 type. Table 1: The crystallographic data [1,2,3] for the gamma brasses and the fitted quadrupole interaction parameters together with Tjtfl values calculated with PC model. Compound Structure a[yl] lattice site 7/"' VQ[MHZ] rfxp Ag5Zn8 £82 9.35 24 Zn(g) 0.43 119(1) 0.43(2) 8 Zn(c) 0 125(1) 0 12 Ag(c) 0.04 8 Ag(c) 0 CusZns Z?82 8.86 24 Zn(g) 0.43 138(1) 0.40(2) 8 Zn(c) 0 139(1) 0 12 Cu(e) 0.04 8 Cu(c) 0 CU9AI4 £>83 8.70 12 Al(i) 0.77 4 Al(e) 0 124.9(3) 0.14(1) 12 Cu(i) 0.89 6 Cu(f) 0.95 6 Cu(g) 0.28 4 Cu(c) 0 4 Cu(e) 0 4 Cu(e) 0 Ag2ln £83 9.91 12 In(i) 0.77 107.9(3) 0.49(1) 4 In(e) 0 107.6(3) 0.13(1) or D82 12 Infe) 0.67 8 In(c) 0 Further experiments including studies on the dependence of the quadrupole interaction on temperature are in progress. References [1] Landolt -Bornstein, Strukturdaten der Elemente und intermetaUischen Phasen, Springer- Verlag 1971 [2] A.Taylor and B.J.Kagle, Crystallographic data on metal and alloy structures, Do- ver Publications [3] Eric A.Brandes, Smithells Metals Reference Book, Butterworth & Co 1983 117 PAC studies on xenon irradiated Ni-Ti and Ni-Sb multilayers P. Wodniecki, T.Gorts*, F.Shi*, K.P.Licb* and M.Uhrmacher* In the ion beam mixing of binary metallic bilayers and multilayers the formation of in- termetallic or amorphous phases is one of the central problems. Recent studies on Ni-Al multilayers mixed with Ar and Xe ions [l] have shown that the PAC method with implanted mIn tracers gives detailed information on the oarly stages of the mixing and the phase for- mation processes. In the present study Ni-Ti [2] and Ni-Sb multilayers were doped with inIn before mixing with 900 kcV Xe ions. The calculated FWHM of the In distribution (40 nm) covered several layers and thus led to equal fractions of probe atoms in both metals. All the implantations, irradiations and the. PAC measurements were carried-out at II Physikalisches Institut dor Universitat Gottingcn using the IONAS ion implanter and four Nal-detector setup. The Ni/Ti multilayer slack consisted of 8 periods of approximately 10 nm Ti and 6 nm Ni evaporated onto Si. Directly after hi implantation the PAC spectrum was fitted with fTt = J = 50% and very broad distributions of frequencies characteristic for the two metals (VQ* = 27.3 MHz and w^1 = 95.7 MHz) indicating that the probe atoms implantation itself mixes the layers effectively without the formation of the amorphous phase (fig. 1). The Xe irradiation with 5 xlO15 ions cur2 significantly changed the PAC pattern. The best fit was obtained with half of the prolms in an amorphous phase described by the quadrupole parameters VQ = 95.5 MHz and 6 •— '.)()%.Th e remaining probes showed broad distributions of frequencies around the values typirji] for Ni and Ti. -nit) o.io Ni/Ti multilayer- as implanted 0.05 0.00 5xio15 Xe ions/cm2 0 100 200 300 tins] Figure 1: Influence of the Xe mixing on the PAC pattern for Ni/Ti and Ni/Sb multilayers. Similar experiments for the Ni-Sb multilayer ('1 periods of 21 nm Sb and 7 nm Ni) were performed. Directly after the inIn implantation no quadrupole interaction typical for the amorphous phase was observed and the experimental R(t) function exhibited at least two components probably connected with the formation of some intermetallic phases. A very high mixing rate measured in UBS experiments for Ni-Sb bilayers (much higher than for Ni-Ti system) can account for the lack of the unique frequencies characteristic for Sb and Ni. 118 Subsequent irradiations with Xe ions of 900 keV energy increased the distributions of observed frequencies and led to the formation of an amorphous fraction, which reached about 30 % of the probes after 6.2 XlO15 Xe ions cm"2. The analysis of PAC spectra indicates that the formation of interrrxitallic compounds takes place simultaneously, but identification of these fractions requires further experiments. The PAC investigations on Ni-Sb compounds of different atomic ratios and crystallographic structures are in progress and should help in the attributing of quadrupole frequencies observed in the Xe mixed samples to the corresponding compounds. References [1] T.Weber, K.P.Lieb and M.Uhrmacher, Surf. Interf. Anal. 17 (1991) 330 [2] P.Wpduiecki, T.Corts, K.P.Lieb and M.Uhrmacher, Proc. Int. Conf. o.i Advance Materials, May 28-31, 1991 Strasbourg, NucL Instr. and Meth. B (in press) * II. Physikalisches Instittit, Universitat Gottingen 119 Magnetic Properties of DyIr2Si2(I) from Mossbauer Spectroscopy Measurements K. Tomala1, A. Blaise2, R. Kmieć, J.P. Sanchez2 /. Institute of Physics, Jagellonian University, Cracow, Poland. 2. Ccntrt d'Etudes \veleaires de Grenoble, FYace. Rare eaith or actinide ternary silicides or gennanides of general formula RT3X2 (where It= rare earth or actinide, T is transition metal and X = Si or Ge) have attracted considerable interest owing to their wide range of peculiar physical properties [1,2]. These intermetallics crystallise either in body centered (I) tetragonal ThCrjSij type structure or in primitive (P) tetragonal CaBejGe^ type structure which differ only by the stacking of the alternate layers. On the other hand. RIr2Si2 materials have been reported [5] to exhibit polymorphism; rapidly cooled samples crystallise in the CaBe2Ge2-type structure (the high-temperature phase) and slowly cooled materials stabilise the ThCr2Si2-type structure (the low temperature phase) [4]. The compounds usually order magnetically at low temperatures exhibiting different types of magnetic structures with magnetic moments localised predominantly at the R-site [3]. The present study reports on detailed hyperfine interaction measurements on the 16lDy and 193Ir nuclei in DyIrjSi2(I).The aim of this work was to shed some light on the electronic structure of the Dy ions in this material. At low temperatures, both the hyperfine field (H/,y) and the electric field gradient (EFG) induced by the 4f shell electrons at the 161Dy nuclei are fashioned by the crystalline electric field (CEF) ground state wavefunction. Moreover, temperature dependence of these parameters can provide informations on the position and nature of excited CEF levels. Or the other hand, the transferred hyperfine interaction data at the 193Ir nuclei are expected to give some information concerning the exchange interactions and the magnetic structure of this material. The 161Dy Mossbauer spectra taken at temperatures between 4.2 K and 45 K. At 4.2 K the data are well represented by a unique set of hyperfine parameters with the magnetic field parallel to the main axis of the electric field gradient. Any hyperfine parameter distribution is ruled out from the observed very narrow resonance line of 4.7(2) mm/s. The spectra taken at 15 and 25 K can still be analysed assuming a static hyperfine Hamiltonian and a unique set of parameters but severe linebroadenings are observed. The linewidth increase with raising temperatere. This behavior is attributed to the occurence of rather slow relaxation of the Dy magnetic moment. Therefore the 15 and 25 K spectra were also analysed in the framework of a relaxation model which lakes into account transitions involving excited crystal-molecular field levels. The 161Dy spectra taken at 35 and 45 K (the latter being taken in the paramagnetic state) show distinctly the slowing down of the dysprosium magnetic moment relaxation rate. This approach enabled us to astimate the energies of the two first exited levels as well as the second (Bij!) and fourth-order (B°) crystal field parameters. The negative sign of B° determines the easy magnetization direction parallel to the tetragonal c-axis. Mossbauer study of the 161Ir resonance in DyIr2Si2(I) was performed at 4.2 K, i.e., in the magnetically ordered state (T^ = 40 K). The 4.2 K Mossbauer spectrum was satisfactorily analysed assuming a single poorly resolved quadrupolar split doublet (AEQ) with narrow linewidth (W = 0.87 mm/s to be compared with W = 0.76 mm/s found in Ir metal). The results clearly show that the Ir atoms occupy a single crystallographic site with no interchange between the Ir and Si atomic positions. The other important information gained from the 193Ir data is the absence of a local moment on the Ir atom and of a transferred hyperfine field 120 at the Ir nuclei even when the Dy atoms carry a moment of 10 fig . The transferred liyperfine fields are produced by the polarisation of conduction electrons by the spin S on the rare earth atoms. The transferred field is thus expected to be, in a first approximation, proportional to S = (gj - 1)J and to the weighted sum of the R magnetic moments in vicinity of the Ir ;.toms [6]. If one considers that the polarisation of the conduction electrons is mainly due to the two neighbouring R planes of an Ir atom and that the coupling within the planes is ferromagnetic it may be concluded from the absence of any transferred field at the Ir nuclei that the interaction between the two R planes is antiferrojnagnetic. The simplest collinear spin structure which would agree with the experimental results is the AF type I structure where the magnetic moments localized on the R atoms form ferromagnetic sheets perpendicular to the c-axis, the coupling between adjacent planes being antiferromagnetic. References [1] E.Parthe and B.Chabot, in: Handbook on the Physics and Chemistry of Rare Earths, Vol.6, eds. K.A.Gschneidner Jr. and L.Eyring (North Holland, Amsterdam, 1984) p.113 [2] P.Rogl, in: Handbook on the Physics and Chemistry of Rare Earths, Vol.7, eds. K.A.Gschneidner Jr. and L.Eyring (North Holland, Amsterdam, 1984) p.l. [3] A.Szytulf* and J.Leciejewicz, in: Handbook on the Physics and Chemistry of Rare Earths, Vol.12, eds. K.A.Gschneidner Jr. and L.Eyring (North Holland, Amsterdam,1989) p.133. [4] H.F.Braun, N.Engel and E.Parthe, Phys. Rev. B28 (1983) 1389. [5] Wang-Xian-Zhong, B.Lloret, Wee Lam Ng, B.Chevalier, J.Etourneau, Rev. de Chimie Minerale 22 (1985) 711. [6] A.M.Umarji, D.R.Noakcs.P.J.Viccaro, G.K.Shenoy, A.T.Aldred J. Magn. Magn. Mater. 36 (1983) 61. 121 Móssbauer Studies of UPdSn R. Kmieć, R. Kruk, R Le.śniowski, K. Łątka1, K. Tomala1 /. Institute of Physics, Jagcllonian University, Cracow, Poland UPdSn belongs to the large family of uranium ternary compounds showing a groat variety of magnetic properties, depending on the degree of hybridization of U-5fstates with the states of ligands. The latter states originate from both d- and p- electrons of transition-metal and main constituents, respectively. In the case of UPdSn, the Pd-4d shell is assumed to be filled up and its role in the hybridization is negligible, Hence, the U-5f electrons are considered in UPdSn to be fairly well localized. This fact arises a.lso from the magnetic susceptibility studies [1]. In contrast to the previous report [2], the magnetic susceptibility of UPdSn exhibits two broad maxima at low temperatures [1,3], associated with the antiferromagnetic states of uranium moments in this compound. It appears that except for the atiferro-paramagnetic transition near 40 K, there is also an additional antiferro-antiferromagnetic trasition near 26 K. Mossbauer spectra with the 23.9 keV gamma rays of u9Sn were taken in the cryostat with a Mossbauer spectrometer of conventional design operating in constant acceleration mode. The temperature of an absorber could be varied between 1.5 and 300 K. The spectra were an- alyzed by computer fits to the experimental data in the thin absorber approximation assuming only static hyperfme interaction. Nuclear energy levels were calculated by numerical diago- nalization of the hyperfine Hamiltonian. The asymmetry parameter, r\ - (VIX - Vyi/ ) / V„, was taken into account and extracted from the spectra obtained below the Neel temperature (T = 40 K). The fitting routine provides the absolute value of the hyperfine field |H^y |, the isomer shift Si, , the quadrupole coupling constant AEg = eQV«, the asymmetry parameter t] obtained as independent parameter from magnetically split spectra, and the polar angle, 0, which defines the direction of H/,/ with respect to the z-axis. The results derived from Mossbauer spectra are presented in Table 1. As expected for the non-cubic point symmetry at Sn site in UPdSn, the Mossbauer spectra show the presence of an electric field gradient, V«, interacting with the quadrupole moment of noSn nuclei. Starting from 38 K, the observed spectrum shows a broadening which can be associated to the local magnetic interaction. Between 43 and 33 K the measured spectra show very interesting behaviour. Namely the intensity of the quadrupole doublet observed above Tjv decreases to zero with decreasing temperature for temperatures below Tjv. It means that the fraction of Sn atoms seeing magnetic hyperfine fields H/,/ changes continuously from zero to one. In addition, at temperatures between 38 and 26 K, the spectra reveal some distribution of magnetic hyperfine field. This distribution decreases gradually from T = 35.5 K as the temperatures approaches 26 K. Below temperature T = 26 K one observes dramatic decrease of the fitted half line width up to the value characteristic for the room temperature spectrum. It is worth to note that all spectra taken below 26 K cannot be properly fitted without inclusion to the fit the asymmetry parameter TJ. This observation is consistent with the.crystal structure distortion observed by neutron diffraction measurements. Especially, the 26 K-distortion leads to the huge jump in the quadrupole interaction constant, AEQ . The temperature dependence of ll/if , exhibits also a remarkable anomaly near 26 K, 122 Tiililo I. "9Sn liyporfiiio interaction parameters in UPJSn. T I"*/ 1 AEQ 0 W (K) (T) (mrti/s) (mm/s) ( 4.2 5.09(1)" 1.80(1) -1.79(6) 84(2) 0.90(1) 15.0 5.0<<(1) 1.83(1) -1.80(6) 85(2) 0.89(1) 20.0 4.96(1) 1.84(1) -1.82(6) 80(1) 0.93(1) 22.5 4.84(2) 1.84(1) -1.83(7) 88(4) 0.97(1) 24.0 4.72(2) 1.85(1) -1.89(8) 90(7) 1.05(2) 25.0 4.61(3) 1.86(1) -1.80(10) 90(8) 1.14(3) 26.0 4.39(3) 1.88(5) -1.14(7) 89(9) 1.37(4) 27.5 4.2(5(4) 1.83(1) •1.10(10) 74(5) 1.38(3) 30.0 4.00(3) 1.81(1) -1.10(10) 81(6) 1.40(3) 33.0 3.50(1) 1.78(4) -J.10(10) 75(8) 1.47(4) 35.5 3.00(4) 1.87(4) -1.10(20) 89(9) 1.61(5) 38.0 2.00(10) 1-81(1) -1.18(6) 90(10) 1.30120) '13.0 - 1.81(1) -1.17(5) - 0.83(3) 300 * 1.81(1) -1.18(5) 0.84(2) Isomer shift, 6i,, with respect to the BalloSn03 source. For K-y = 23.875 k«V: lmin/s s 7.9«3 • 10"8 eV's 19.253 MHz. References [1] V.H.'lVan and R/LVoc, J. Magn. Mngn. Mater. 102 (1991) 74. [2] T.T.M.Palstra, G.J.Nieuvenhiiys, R.F.VHastuhi, J.van den Berg, J.A.Mydosh, ./. Magn. Magn. Mnter. 67 (1987) 331. [3J II.A.Robinson, A.C.Lawson. K.H.J.Bufichow, F.R.de Boer, V.Secliovsky, R.R.Von Dreele, J. Mngn. Mngn. Mnter. OS (1991) 147. 123 Investigation of Compton Scattering in Ag A. A ndrcjczuk*, L Dobrzyński1, S.Kaprzyk2, J.Kwiatkowska, F.Maniawski, E.Żukowski1 The directional Compton profiles J(q), carrying the information on electron momentum distribution (1,2], have been measured for a single crystal of silver in three major crystallo- graphy directions, Measurements were performed with 7-ray source, 662 keV line of 1370R, at the Oonipton scattering facility at the Warsaw University Branch in Białystok. The single crystal ingot of 5N-pure silver have been grown by the Bridgman method. Three disk-shaped samples were cut from the ingot perpendicular to [100], [110] and (11 i j directions. Accuracy of the discs orientation was better than 1.5°. Surfaces of the samples were ground with abrasive powder (grade 500-1000), and subsequently chemically etched and electropolished. The results of the experiment, after having been corrected for Inherent instrumental factors, are presented here in terms of directional profile differences. Fig.l(a-c) shows •/iio(<7) - ./ioo(?)i Jin{q) - Jno{q) and Jm(?) - Jioo(q) respectively. AJ ,06 .06 [110]-[tOO] ,O'i • .01- • .02- .1 .00 V. .00 .02- H 1 •( -.02- 1- v -•0Ł -.06 -.06- qlo.uj (VI- .06- [111]-[100] .04- .02- I I *l M "I I .00- Figure 1. Directional profile differences determined for silver .02 a) Jno(9) - ^100(9), -.o;- b) Jn\( q (o.uj 124 The directional differences AJ(g), rather than Compton profiles, are used in the analysis as these can be, with greater certainty, compared with theoretical calculations. The comparison of the results on a relative basis eliminates the isotropic part relating to the closed shell which is of little interest, and also minimises residual systematic errors from the individual profiles. The presented experimental profiles remain convoluted with resolution function which for our experimental arrangement can be approximated by a Gaussian with the width of 0.4 au. The comparison with theory requires convoluting the theoretical profiles with a residual instrument function. Another approach i.e. deconvolution of experimental profile can also be applied. . Aiming for more precision in the data we shall next perform the experiment using 198Au source, however some conclusive features can be clearly seen in the results obtained so far; one of them being that the major anisotropy comes from the Juo(g)- This is the profile measured along a face diagonal of the unit cell i.e. the nearest-neighbour direction for this structure. The profiles J\n(<]) and Jioo( References [1] J.W.M.Dumond, Phys.Rev., 33 (1929) 643 [2] M.G.Cooper, Rep.Frog.Phys., 48 (1985) 415 [3] S.Fuster et al., Phys. Rev., B42 (1990) 7322 [4] N.I.Papanicolaou fit al., (unpublished) Permanent addresses: 1 Warsaw University Branch in Białystok 2 Academy of Mining and Metallurgy, AGH, Cracow 125 Calculation of the Rotation Rate Field on the Basis of the Experimental Texture Data A.Hiirzmnńshi1, l(.Wi In ti'x! mo si udies of polyci yst JVI lino male rial an important variable which describes plastic deformation and texture formation is the rotation rate Held (RRF) [1-4]. Up to now only l.li ;IIKI c, for deformation t.2 = 2.'18, agree well with the predicted deformation textures b and d l-fsiicctivelv. Kxperimenl »l a) rrcitiiclr.'f) b) O ) 1 ^_ 1 ES "' ; ES ' r-. \ • <;^ :3 s> O.[l ¥ - O.D.F --Min I'lltH PHI;: l-'iyurc 1: Experimental and predicted rolling textures of (70%Cu-30%Zn) brass; a) experi- mental texture for /,] - 1.98, b) predicted texture for 126 - f1. |'!K|łft illlMll.ll I" I'l ("llH-llill d) ' (O- . /I.Li- //•I' ; '^"- . .las . .. u'£~- _.. t) LI K -Jpy 'Si. s. «.l) F UTtLt < 'u i in s in * t*> t %o J: (continued) c) experimental texture for tj = 2.48, d) predicted texture for t-t — 2.48 From tlie fact that RRFs obtained in the above described way predict the deformation toxture correctly one may draw the conclusion that experimentally determined RllFs can be lined to predict the texture modification during subsequent rolling stages and in any other twhnnlngical process involving plastic deformation. References (I] II..T.Bungc Cristall u 7'ecAniit 5( 1970) 145 [2} A.Clement Male.r. Sci. Eng. 55 (1982)203 (3] K.Wierzbanowski et al., Cryst. Res. Technol. 19 (1985) 201 (4] K.Wierzbanowski et al., Phil. Mag. A51 (1985) 145 (5) K.Wierzbanowski et al., Archives of Metallurgy 34 (1989) 335 |f>) J.Pośpiech et al., Proc. 4-th lnl.ConJ.on Texture (1975) 23 Permanent addresses: 1 Academy of Mining and Metallurgy, AGH, Cracow 'Ź Inslitute of Metallurgy, Polish Acaulemy of Sciences, Cracow .'I Nrl.herlandii Energy Research Foundation, ECN, Petten (NH) 127 Positron Lifetime Measurements in (3 -Vanadium Oxide Bronzes E.Dryzek and W.Górniak1 ') Murie Curie-Skłodowska University, Lublin. Positron lifetime spectra in /?-vnnndumi oxide bronzes M^VjOr, (M — Li, Na, Ag, Cu) were measured as a complement to the prior measurements of the peak height of the angular correlation quanta vs. temperature. The vanadium oxide bronzes are .semiconducting noostoichiometric compounds having donor ioms M substituted into a distorted V2OK framework. Sites which can he occupied by the M ions form two rows within tunnels surrounded by oxygon polyhodra along the crystallographic b axis. So they errato one-dimensions! sublattice. The value of a; parameter corresponds to the number of occupied sites in the tunnel (x < 0.67, if r. ^ 0.67 all sites would be occupied). The kind of M ions and the value of x parameter alfso influence on the location of the sites available for M ions in the a — c plane. The presence of the nonoccupied sites which can be treat as vacancies or form the linear group of them according to the evidence of the clustering of donor ions roust cfFect the posttrr-n penetrating the tunnels. The stoicluometry of the bronze *ind in particular the kind of M ions should influence on the positron lifetimes ns it wan noticed in case of temperature dependence of peak coincidence count rate. The lifetime spectra of positron annihilation in vanadium oxide bf onzes were measured using a conventional fast slow spectrometer with a resolution (FW1IM) of about 300 pB. The lifetime spectra were decomposed with the POSITEONFIT program. The best results which are presented in Table 1 were obtained for two exponentials convoluted with the Gaussian resolution curve. The values of rj except one in Cuo.aVjOs are slightly greater than the built tifptirnes in tbi« typical group-TV elemental anrl ITI-V and II—IV compound semiconductors. They could be compared, with the calculated positron lifetimes in vacancies or dWacancics in those soinicondurlors. Tnble 1. Positron lifetime components in vanadium oxide bronzes. Bromie § T-y(ps) h(%) T2(ps) r: /2j%) J 1 Lio 45V2O5 J 334(1) 98.4(0.4) 741 (6OT 1.6(4) 289(1]* 98.4(0.4) 696(57)" 1TT(4) Clio 3V2DS '221(31' 76.6(1.9) 386(8) A^.4V2Or, 28^27" 95.3{l.2r 518(33) References |1) ,l.l)ry-/.-l( and H.Hngowska, phy*. ninl. sol (a) 118 (1990) 61. h>| K.Drv/.-li r 128 Study of the Tungsten Bronze Ago.01WO3 Using Positron Annihilation Method J.Dry/.ek, A.Polacwk* and E.Dvy/e.k (* Warsaw Ihuvrrsity) The silver doped tungsten trioxide Ago.oiWOa exhibits a strictly linear reversible and re- producible dependence of resistivity t)n temperature over 300 — DOOR" range. So it behaves like a "metal". The Ag'ions are (probably randomly) distributed among Uie lattice holes of the WO3 oxide framework. The conduction electrons delivered from Ag atoms occupy the W5d/t2O/ -~ O'lp/tcI orbital states of the empty antibonding band according the Morin- Goodenougb-Sienko model. In our investigations we used the positron annihilation experiment and the thermoelectric power measurement. Tn Fig. 1 there are presented the peak height of angular correlation of aniiih:!r*ion radiation as a function of temperature for silver doped Ago.oiW03 and empty framework WO3. The increase and then saturation of the peak height n.s temperature for Ago.oiWO.i is characteristic for metals (e.g. Cd, In, Pb) where positTon is trapped by the thermal vacancies. It indicates that, in this case, a thermal positron trap is also generated. One can obtain from this data, assuming the two state model that \\t — (0.39 i 0.01) eV 14 and /j£exp(5£/fcfl) « 1.6 • 10 l/s. The explanation of these results seems to be that the Ag+ ions create some clusters having an ordered substructure which strongly effects the positrons. The trap is just a negatively charged "vacancy" in the substructure. At the temperature above 2Q0°C the substructure becomes completely disordered. In the case of WO3 we could not observe such thermal effect because there are not this kind of substructure. The small decrease above 250°C is caused by the fact that the monoclhuc structure of WO3 changes into the orthorhombic one at 330°C The above picture agrees also with the observed flemkonducting properties of Ago.oiW03 as revealed by the Seebeck effect measurements. The low concentration of the clusters in this compound cannot create any continues regions across the crystals for moving electrons. It is worth noticing that similar behavior of the peak height as for Ago.otWOg we observed for WOj^o- The measurement of Seebeck coefficient showed that WO2.90 behaves like a "poor" metal. 1.15 T Figure 1: The peak height versus temperature for WO3 ind Ag0.oiW03. The solid curve is the best fit of the two- state model. 100 200 300 temperature (°C) 129 Effect of the Cooling Rate on the Structure of the Wustite Phase in the Model Iron Catalyst for Ammonia Synthesis A. PaMek-.Iamzyk1 and B. Miczko2 /. Department of Chemistry, Jagiellonian University, Cixtcow. 2. Regional Laboratory of Physico-Chemical Analyses and Structural Research, Jagicllonian University, Cracow. Model catalysts for ammonia fynthesie containing « 50 wt % of wustite were prepared by iHfltini; and cooled in various ways. The samples were studied by Mossbauer apectroscopy •ind X-ray diffraction technique. MoKsbauer Kper.lra showed that changes within the error range occured in the magnetite l>h;iM! of the catalyst. In the wustite phase two different Fe2+ surroundings were revealed, licarraiigments of defects, conditioned by the cooling rate, resulted in forming two kinds of wiitililu with different defect structures. Wustite Fei_20 is formed from the other wustite K«»|_.rO, wher« x > z. Reaction given by Greenwood and Howe (l-4z) PBI-J-O -» (l-4x) Fe^O + (x-z) Fe3O4 is valid. The longer time of cooling, the more advanced disprqportionation reaction is ob- served. Thus, the relative contribution of the wustites is mainly affected. Higher content of wusi.ite having the structure close to the stoichiometric compound was found in samples ex- to prolonged cooling. Type of defect structure shows slight dependence on the cooling The high resolution scans over the wustite reflections in the X-ray diffraction patterns ronlirincd the Mossbauer results. Two fundamental lattice parameters of 4.325(5) A and 4.295(5) A were calculated. 1 (XO IK I CO) UW i o an Figure 1: The Mossbauer spectra of model catalysts recorded at high and low velocities. 130 Pm-on-Disk Experimental Setup for Tribological Investigations .). Lrkki, N. Preiksehas1, 13. Oil1, Z. Stachura /. hislitutc of Nucltttr I'hyaics, Minister University, Ccnnuny. fvle.chaiii< ai properties of materials may he significantly influenced by the implantation of foreign species into the surface layer [I], This technique gives a tool for mixing well controllable quantities of almost any element with the host, material, producing nonstandard, unique structures. Metals that are itninisible as liquids can be alloyed, and one material may be introduced into another at a concentration that could never be achieved traditionally. Modification of surfaces with ion beams may be performed in the Institute of Nuclear Physics using 70 keV mass separator or Van de GraafTaccelerator. Tribological properties of treated materials are examined by macroscopic, techniques as friction and hardness measure- ments or profilometry. The niicrostructure is investigated using SEM and the nuclear physics methods as RUŚ, ERI), PAS or X-ray diffraction. For friction force measurements an experimental setup, so called pin-on-disk machine, has been constructed. The principle of operation bases on the measuring of tangential force acting at I lie horizontal arm pushed against turning disk made of investigated material. The area of contact is defined by the small ball or a pin mounted at the end the arm. The friction coefficient is determined from the knowledge of applied load and measured force. During measurement, simple optical c.ircutry provides information on the. stability of sample revolutions. Data acquisition system is built around AD card using IBM PC microcomputer. The specialized computer program controlls the experiment and supplies tools for interpretation of measured data. Hy placing the pin-on-disk setup into the vacuum chamber one can also investigate tri- bological behaviour in low pressure conditions or in inert gases atmosphere. Proper choice of pump system is of great importance, as the friction properties depend strongly on the pKsiene*! of the traces of oil and other lubricants in the system. Actually, the combination of votary and tnrboinolecuUir pumps has been used, and will be replaced in the future with the nynpuinp. The great number of physical and chemie?! factors influencing the. tribological behaviour of investigated system cause difficulties in interpretation of experimental data [2]. Materials important, from technological point of view are rather complex and Mirty' (steels, carbides) and thus not very suitable for investigation of basic physical phenomena. Foi this purpose some ni'tp.- "clean' physical system should be chosen. It seems reasonable trying to use monocrystals as basic experimental material. Several mechanism responsible for friction and wear may be studied using such a simplified model [3]. In I he present, short report some preliminary dala on implanted and not implanted silicon ni'.Miociystals are presented. Si samples (< It I > diiectiou) were, implanted using 1NP mass eparator with lie and Ar ions with the energy of 70 keV ami the dose of 1017 ions/cm2. Need, •' <>fl!i —i o- 1000 I MO SO" 1000 1500~ Tims (s) 2000 Tim* (j) Fvjnrc I: The fiiclional behaviour of not implanted (—), He implanted (o) and Ar implanted (4) Si nionocryfitals. Left: measurements performed in He atmosphere. Right: vacuum •l-lf)-" Torr. Tor assuring inert surrounding, the samples were measured in He atmosphere. However, significant difference between friction in vacuum and in He has been observed. The very pronounced decrease of the friction for implanted samples is clearly visible. For vacuum conditions the effect was stable in time and its magnitude was approximately the same for both implanted elements. Microhardness measurements (Vickers) show increase in hardness for He implanted samples (more than 25%). Unfortunately, the increase for Ar implanted sample!) could not be measured because the Ar implantation range was much smaller than minimal accessible indentation depth. Different behaviour for He implanted samples in lie atmosphere requires further investigation. Acknowledgements I'in-on-disk setup was build in cooperation with Institut fiir Kernphysik of Wilhelms VVest- falisches Universitat Munster in Germany, which also was the supplier of the whole vacuum system. References [lj (J. Doarnaley and N.E.W. Hartley. Thin Solid Films, 54 (1978) 215. \'i\ DM. Buckley, J. Ferrante, M.D. Pashley, and J.R, Smith. Mat. Set. Eng. 83 (1986) 177. j:i| M. Grunge and H.J. Kreuzer (Elds.) Adhesion and Friction. Springer Series in Surface Sciences, Vol.17, 1989. 132 EBS and ERD Analysis of Thick Targets S. Kopta, J. Lckki, and B. Rajcliol The usefulness and detection ability of standard UBS measurements may be significantly enhanced by the proper choice of bombarding particles and their energy. This is due to the fact that For many cases tho scattering cross section is much higher than for the pure Rutherford scattering. As an example, for C target and bombarding II beam, the nuclear resonance at 1.7 MeV increases the scattering cross section by the factor of 12. This effect is particularly significant, for proton beam and the targets consisting of light elements. Measurements of this type are called Elastic Backscatlering Spoctoscopy (EBS). The complementary technique, commonly used for determination of hydrogen and its isotopes, Elastic Recoil Detection (ERD) may be used in the same experiinontai setup as EHS. However, optimal detection of recoiled target nuclei requires different geometrical conditions for the detection and - in the simplest approach - removing the scattered beam from detection track by introducing the stopper foil in front of the detector. Both processes are closely related and may be described using similar mathematical mo- dels. Paralelly to many numerical algorithms presented in the literature we have found an- alytical description of the EBS-ERD experiment [I]. On this basis we have developed the computer program calculating simulated spectra for any bombarding beam and mullielemen- tal, uniform targets. 12000 10000- 8000- 6000- t) 0) 4000 - -łD— O 2000 - 0- Energy (MeV) l-hjurr I: Experimental and calculated spectra of 2.4 MeV proton beam scattered on the •ulsi.lire of uric acid and hydroxyapalite. Fitted stoichiometry: Ca5CaC Sapping pownr of tin* thick, compound target was described using Bragg-Kleeman acldi- lv mii- [I] and fitted to the semi-empirical formula [3]. This general treatment was applied 133 not only for bombarding beam, but also for recoiling nuclei on their way towards the detec- tor. To make possible the analytical computations, as the first approach, the scattering cross section was taken to be of Rutherford type. IL one of the final steps of the algorithm, ipectra were rescaled using real, literature data. This simplified method gives good approximation of the reality, neglecting however some second order effects (i.e. influence of straggling on the shape of scattering resonance yields). Additional factors affecting the shape of measured spectra as: the beam energy spread, the resolution of the detection system, energy straggling, and, ia the case of recoils detection, the influence of range foil, were also built into the model. Paralelly to routine analytical applications, the proposed method is particularly suitable for elemental contents determination of biological samples. It gives also the data necessary for optimal choose of experimental conditions and to estimate the chances of obtaining valuable experimental data before performing the measurements. References [1] S.Kopta, J.Lekki, and B.Rajchel. Report of Institute of Kuclear Physics, No 1574/AP (1991). [2] W. Chu et. al. Backscattering Spectrometry, Academic PreBS (1978). [3] S.Kopta, R.Hajduk, J.Lekki, B.Rajchel, and A.Z.Hrynkiewicz. phys. slot. sol. (b) 113, 295 (1989). 134 Two Beam Line System at 70 keV Mass Separator for Materials Investigations M. Drwiqga, E. Lipiriska, B. Raj did, and M. Wierba Composition and structure of a thin material surface determines many chemical and me- chanical material properties [1,2]. For instance, I lie creation of the thin isolating layers on the material surface can change the corossion rait?. Thin layer of desired properties can be created in many ways, e.g. by the implantation of heavy ions into the target we can create a very thin layer of doped ions simultaneously controlling the structure of the layer. The Ion Beam Assisted Deposition (IBAD) [3] is the recent technique used for the creation of mul- tilayer and multielomental complex materials. The IBAD method may be performed, using two independent ion beams: the first ion beam is used to perform the deposition of chosen element on the target surface (by the sputtering of the auxiliary target) and the second, si- multaneously bombarding the target, introduces the implanted elements into the surface and performs additional mixing by recoil implantation. By a right combination of auxiliary and main targets and the parameters of both ion beams, the new multilayer complex materials can be produced. After modernization, the 70 kV INP mass separator will be used in the IBA1) mode. This required a second ion beam line, responsible for sputtering and deposition of chosen element on the target. Final geometry of the modified mass separator is shown in Figure 1. Targrt Second Ion Lens Ion source X L> Ion source i'iyuir I: Two beams arrangement at INP mass separator. References [1] G.K. HumVr. C.A.Carnsellii cl all. NIM B46 (UM)O) 384. [2] .1.1*. Hiersack, S. Berg rl all. NIM B59/60 (I9!)l) 21. [:ij G.K. Wolf, W. KnsiiiRor A7A/BI>U/«0 (|!I!H) I?:J. 135 Microanalysis Using Synchrotron Radiation W.M. Kwiatek, T. Cichocki1, M. Gałka1 and C. Paluszkiewicz2 /, Academy of Medicine, Cracow, Poland 2. Jagiellonian University, Cracow, Poland The SIUXE (Synchrotron Radiation Induced X-ray Emission) technique has been applied for several years in different fields of science. Since it has a number of useful advantages [1] it has been applied to inicroaiialysis of thin tissue sections in order to investigate trace element distribution in normal and cancerous kidneys. All the samples were surgically obtained in the Clinic of Urology at, the Academy of Medicine in Cracow, Poland and were investigated in I1ASYLAB at DESY, Hamburg, FRG with the synchrotron beam of 70 /xm x 100 /tm. Although only a few samples were measured so far, the results obtained seem to be promising. Enhanced trace element cancentrations in cancerous parts of kidneys have been observed. The samples wore obtained during surgical operations, frozen in the liquid nitrogen, and cut into 10 /an thick sections on a cryomicrotome. The sections were placed on a 2.5 fin\ Mylar foil. Adjacent sections were histologically investigated in order to choose the right area for TE analysis ami in order to define the cancer type. The majority of the samples have been classified as "carcinoma clarocellulare", and one sample was identified as "angiomyolipoma". In each rase a boundary between the normal and the cancerous part of the kidney was seen. Each sample was irradiated for 300 s with a 70 /mi x 100 /mi photon beam. The beam was filtered by a 125 /tm thick aluminum foil. There was no absorber in front of a 50 mm2 Si(Li) dełoctor s» portu red by tantalum collhnator with a hole of '.i mm in a diameter. All samples w<-rn analyzed during ono fill of the DORIS storage ring. 10 '---J Fe Zn to t -' 10 ••= t; ;j o 10 ~ 100 200 300 400 500 100 200 300 400 500 Channel No. Channel No. Figure I: Typical SR1XE spectra of kidney section (left) and kidney cancerous part CC (right). The existence of LO elements (S, Cl, K, Ca. Mn, Ke, Cu, Zn, Ur, and Rb) was determined in three types of sections: normal kidm-y. rniicernus CC (Carcinoma Clarocellulare), and 136 cancerous A (Angiomyolipoma). Each area of interest was irradiated in five different points in order to average the value of trace element concentrations. Such a point-to-point analysis was performed in the distances of 500 fm within the selected area. Figure below shows typical spectra of the investigated sections. The spectra were normalized to the number of incoming photons. By a point-to-point analysis of the normal and cancerous sections one can observe sig- nificant differences in TE concentration levels between the samples. Table 1. sumarizes the results obtained. Ratios of elemental concentrations with respect to the normal kidney tissue is presented in order to give an impression how much the concntrations vary in dependency on section type. Table 1. Ratios of elemental concentrations in respect to the normal kidney tissue; CC-carcinoma clarocellulare, A-angiomyolipoma. Element Normal Kidney Kidney Cancer CC Kidney Cancer A S 1 1.9 0.025 Cl 1 1.8 0.031 K 1 3.9 0.025 Ca 1 1.7 0.016 Mn 1 3.0 1 Fe 1 4.5 3.5 Cu 1 0.9 0.6 Zn 1 1.4 0.4 Br 1 0.6 0.2 R 1 2.6 not detected Based on the present results one can conclude that the SRIXE technique is a useful and valuable technique for TE analysis in thin tissue sections. Particularly interesting is the fact that concentration of almost all determined trace elements in cancerous CC part of a kidney have increased values. Although the oservations were based on measurements using only two samples, the results obtained may serve as a guide for future research and may help to improve the understanding of the ethiopathogenesis of the cancer process. Two-dimensional maps on the boundary between cancerous and normal kidney tissu sections would be of great interest in the future analysis. Since the data seem to be interesting and promising to learn more about the cancer such investigations ahould be carried out. Acknowledgements The authors are thankful for a nice collaboration and the financial support from HASY- LAB and DESY in Hamburg. Also, we are grateful to the SYRXF Group at HASYLAB for the assistance during the measurements. References |1] E-E. Koch. Handbook of Synchrotron Radiation, North-Holland Publishing Co., 1983. 137 Application of FTIR, PIXE, and EBS for Trace Element Analysis in Biological Samples W.M. Kwiatek, J. Lekki, G. Paluszkicwicz1, and N. Preikschas2 /. Jugudlonuin University, Krabów, Poland 2. Institute of Nuclear Physics, Minister University, Germany The knowledge of elemental com position of some biological and medical samples is of ma- jor interest, for both the. basic research, medical treatment and prophylactics. Recently, we have analyzed renal stones using (lie FT III and llio PIXE techniques [1], During our investi- gations it ha« appeared that the renal stones are basically composed of different compounds as: oxalates, phosphates, uric acid and their mixtures. The most common trace elements observed in the investigated stones were: Fe, Cu, Zn, 13r, and Sr. Choosing a standard for PIXE measurements one has to consider the matrix effects as well as the possible change of an organic matrix composition during the ion beam irradiaiion [2j. In order to obtain a proper trace element concentrations the correction of matrix effects should be applied. The data concerning the most prominent matrix elements may be obtained by the use of complementary techniques. The FTIJl spectroscopy seems to be an ideal technique to give a rough determination of sample composition. The EBS technique can determine a proper stoicliioinetry of elements that form sample matrix. In our previous studies we were using as an external standard IAEA SRM II-5 (animal bone). Its chemical matrix composition seemed to bo similar to the most of investigated kidney stones. Determination of its elemental composition, especially light, elements, enables to apply matrix effect correction procedure. In order to investigate changes of both the matrix composition and trace element concentrations due to beam - target interaction we have also measured an annealed sample of the H-fi standard. All samples won; prepared in the .'fame way as thick targets. PIXE and EUS measurements were performed with tlio proton beam of 2.4 MeV obtained from, the small cyclotron 0- 15000 15000 -I 10000- 3 O o 5000- ola" o.io i.6o i-so i.io Enargy MoV En«rgy MeV Fiourc 1: Rla.sl.ic backscattering spectra of IAEA SRM 11-5. Left: sample prepared in a room lompnni.tiirfl fitted sloicliromctry PriNrO^GaeCzo'lH. Right: sample annealed at 600° C - lilted skiiohiometry P;)N|O|&ra<;C:,ll^. 138 iii order to perform more detailed analysis of X-rays production and detection we have In taki1 inln account I wo far tors. Firsi, beam particles entering the targets loose energy depending on the. target matrix composition. Thus, X ray production, proportional to energy dependent ionization cross sections is depth dependent. Second, induced X rays, passing the target before reaching the. detector are attenuated !>y the target matrix. After stoichiometry determination, beam energy degradation was calculated, using stopping powers calculated by the computer code TRIM (3). This data, in form of dependence between target depth (in mass units) and energy of penetrating beam were the input for final algorithm, which was performing two tasks: 1. Calculation of X rays production as a function of depth. 2. Estimation of X rays attenuation before reaching the detector. The effect of secondary emission of absorbed X-rays was estimated l.o be not significant. Following our procedure we have analyzed trace element content in I lie samples. Applying described corrections we were, able to determine trace, elements content in annealed 11-5 standard. As one can see the annealing process changing the matrix composition has obviously changed the concentrations of trace elements. 5(10 Sr 400- Sr 100- 200 400 200 400 Channel No. Channel No. Figure 2: PIXE spectra of 1A.F..A SR.M H-f» (peaks of interest marked only). Left: sample prepared in a room temperature (concentrations [ppm]: Fe 79, Zn 89, Sr 96). Right: sample annealed at 600° C (concentrations [ppm]: Fe 80, Zn 150, Sr 580). This study emphasizes the need of using complementary techniques for trace element analysis on biological samples. FTIR gives a possibility of a rapid, rough determination of a sample phase structure, that is very helpful for the further stoichiometry analyses. Stoichiom- etry of biological samples, consisting mainly light elements, may be sufficiently determined by the means of proton backscattering, considering high, non-Rutherford backscattering cross sections. The advantage of combining the PIXE and EBS techniques is that they may be per- formed simultaneously at the same experimental conditions. The described measurement and computational procedure seems to be a good tool for trace element analysis in thick targets. References [1] C.Paluszkiewicz, W.M.Kwiatek, and M.Gałka. Nuci /nsir. and Melh. in Phys. Res. B49 (1990) 234. (2) M.Cholewa, G.Bench, B.J.Kirby, and GJ.F.Legge. Nucl.Inslr. and Meth. in Phys. Res. B54 (1991) 101. [ił] .I.F.Ziegler, J.P.Biersack, U.Littmark - The Stopping and Range of Ions in Solids, Perga- mon Press, 1985. 139 Determination of Hg Concentration in Gases by PIXE E.M. Dutkiewicz, W.J.P. van Kuijen1 , F. Munnik1, P.H.A. Mutsaers1 , E.Rokita2, and M.J.A. de Voigt1 1. Eindhoven University of Technology, Eindhoven, The Netherlands 2. Institute of Physics, Jagiellonian University, Cracow, Poland Mercury is a well known toxic, element present in the environment usually at very low concentrations, but it may enter very easily into human body by ingestion or inhalation and accumulate there. Accumulation causes that mercury is so dangerous for human organism. So far many pathological alterations have been related to the elevated mercury level in human organs [1], however, a complete and consistent picture of mercury metabolism remains obscure. Moreover, as mercury has a high vapour pressure at ambient temperature (10~3 mm Hg) its detection in gaseous phase is an important issue. On the other hand, the existing analytical methods for investigation of mercury concentrations [2,3,4] are complex and time consuming, Special attention has to be paid to the problem of mercury escape at different stages of the experimental procedure, which can be a major source of errors, especially for very low concentrations. Therefore a new method for the determination of mercury concentration in gaseous phase was developed. The method consist of two steps. In the first step, the stable compound, mercury sulphide is formed. For this purpose sulphur was deposited on a filter and the gas under investigation flew through the filter. Different filter materials as well as the sulphur deposition procedures have been tested. Millipore filters (pore diameters 0.45-0.8 fiin) and deposition of sulphur from aqueous solution of Na2S2O3» 5H2O (40 g/1) were found to be the most suitable. The pre- liminary measurements revealed that the most homogeneous covering of the filter by sulphur was obtained this way. Filters were immersed in the stirred solution of sodium thiosulphate immediately after having precipitated sulphur by the addition of HNO3. In each experiment, two air dried filters were mounted in the Hg-sampler. In front of them was placed an unprocessed one (Nucleopore, pore diameter 0.4 fim) as a dust trap. A water pump behind the Hg-sampler forced the gas flow. Volumes of pumped air and the temperature were measured. A vessel with mercury, weighed before and after sampling, was mounted in front of the sampler for calibration purposes. In the second step of the method the amount of mercury absorbed on the filters was de- termined by means of proton induced X-ray emission (PIXE) and neutron activation analysis (NAA). Since PIXE analysis was limited to one element only, the proton energy was optimized to obtain maximum signal to noise ratio. On the basis of calculated cross-section to background ratio as well as of test measurements a proton energy was adopted. The detection limit of the method, expressed as the minimal amount of mercury which has to flow through the filter equals to 30 ng and 2 ng for PIXE and NAA techniques, respectively. The determination of mercury concentration in the gas under investigation was performed on the basis of the calibration curve (Fig. 1). 140 Hgłng/cmZ} 20 10 Q2 0.4 0.6 0.8 Figure 1: Concentration of mercury chemisorbed on the filter vs the amount of mercury which flew through the filter. The experimental errors (standard deviation due to counting statistics) of the PIXE method are given. The influence on the calibration curve of different flow rates (1-5 1/inin) as well as of dif- ferent concentrations of mercury vapour in the air passing through the sampler were checked. The results revealed that a linear relation between the amount of mercury passing through the sampler and the amount of mercury deposited onto the filter was observed at flow rate 1-4 1/min and concentiation of mercury in air below 1 /ig/m3. The NAA analysis [5] involved a single 5 h irradiation in the nuclear reactor. The neutron flux was 51013 n- cm"3' s~l. The whole filter was irradiated together with the reference material (IAEA fish flesh, MA-A-2). After a decay time of 30 d, samples were measured during 24 h using Ge(Li) detector. The full energy* peak of 2tf3Hg (279.2 keV) was used to determine mercury content. Our method was also applied to determine the concentration of mercury in natural gas. According to the widely accepted norms, the earth gas may contain up to 30 ng Hg/m3. In this study we have determined the mercury concentration level at 4.2 ± 0.3 ng/m3, which is well related to the detection limit of the method (1 ng/m3). References [t] E.J. Underwoou, Trace Elements in Human and Animal Nutrition. Academic Press, New York 1977 p. 375. [2] E.A. Hakkila and G.R. Waterbury. Anal. Chcm. 32 (1960) 1340. [3] K.Dittrich, Atomabsorptionsspektrometrie. Akademie Verlag, Merlin 1982 p. 149. [4] E.Szyszko. Instrumentalne Metody Analityczne. PZWL Warszawa 1984 p.512. [5] J. Versieck, L. Vanballenberghe, A. Wittwk, G. Vermeir, C. Vandecasteele. Biol. Drace Elem. Res. 16 (1990)683. 141 Analysis of Fluorine Content in Some Raw and Fired Polish Clays J. Urban and P. Wyszomirski1 /. Academy of Mining and Metallurgy, Cracow Fluorine content in some representative samples of Polish clays was determined. The majority of them are used in Polish ceramic industry for the production of bricks, stonewares and fireclay refractories. They are represented by clay rocks of different age and show distinct variability of mineral composition. The content of fluorine was determined using PIGE method. During 1.5 years of studies the measurements conditions were improved and the detection limit of fluorine was lowered from 100 ppm to 30 ppm. More than 30 samples of clay were analysed. The content of F in raw material varies from ca 300 ppm (Jaworzno) to 1300 ppm (Zebrzydowa). In the majority of samples it ranges from 500 up to 900 ppm. As follows from X-ray analysis, in some cases" we observe a tendency to an increase of F concentration in clays containing more mixed layer minerals and smectites. After firing of clays in 1200" C, the content of F decreases rapidly - in most cases below 100 ppm. Taking into account the temperature of firing bricks (ca 1000° C), the global emission of the fluorine in production of bricks was determined (Fig.l). The obtained results are comparable with the emission of this element by metallurgical plants (mainly of aluminium) and by chemical industry (production of phosphate fertilizers). Figure: 1. Global output of ceramic clays in Poland in the years 1980, 1985, 1989 and approximate value of fluorine emission during firing. 1980 1985 1QB9 110 ten] References P.Wyszomirski, .1,Urban Emission of lluorine during firing of Polish clays. In print Ochrona Powietrza (in Polish). 142 P1XE analysis of trace elements in vegetables cultivated in Cracow's small gardens "Male Błonia" W. M. Kwiatek, E. Ma.rrzcw.ska, S. Szymezyk, and L. Glebowa PIXi'l (Proton Induced X-ray Emission) technique was applied lo investigate trace element concentration in vegetables which were cultivated in Hie small gardens inside ih<; city area uf Cracow. It is known that region of Cracow is highly polluted and therefore the authors of this paper were interested in determination of toxic, elements conentralion level in cultivated vegetables. The increased level of such elements may have the negative inlluance on the methabolic process in the organisms and thus on the human health. Three kinds of vegetables (carrot - C, parsley - P, turnip - T) were chosen for this invus- tigation. The vegetables were sampled from 12 lots located in the "Male Błonia" Gardens in Cracow. Samples were prepared from the underground - U and the above-ground - A parts of the plants. All the plants were rinsed with destilled water and then dried. The dried samples were homogenized and pressed into 2 mm thick and 10 mm in diameter pellets. The concentrations of the trace elements in plants and soil were determined using an external standard technique. As reference material for plants and soil the standards Ci - 1 [cabbidge lives) and Soil - 7 (IAEA) were used respectively. The samples were irradiated with a 2.5 MeV proton beam obtained from the small cy- clotron C-48. The beam current was about 10 nA on the target. The spectra were registered for 600 s with a Si(Li) detector with 180 cV energy resolution for 5.9 keV of an 50Fe source. The concentrations of 17 elements (BT,Co.,Cd,Cr,Cu,FetMn,Mo,Ni,Pb,Rb,Se.,ST, Ti,V,Zn,and Zr) were determined. As shown in Fig. i the average concentration levels of Pb, Mo, Zr, Fc, Ca, and Mn are much higher in the above-ground part of the vegetable than in the underground parts. In case of V, Mo, and Cd the observed average concentration levels in the samples were higher than levels determined in the soil. The numbers presented in the figure are the mean values of all samples of the same kind. It is obvious that the differences between the vegatables parts in trace element concen- trations arc not only due to methabolic. process but the envinronmental pollution should also be considered. Therefore in order to determine more specific function of trace elements in the plants as well as circulation process in th« environment more detailed analysis has to be performed in the future. '13 40' 11- 10- 38 TA O.30 OA JA a CA PA 120 0 !19 8 3 cu TU 0 J- CU PLI PA TU 1- 1 0 ~T—' -T- ^ 'I'" ~r~' 1 Pb In soil - 110 ppm - In •oil 3.!5 ppm CA PA TA E4-^ 300- a TA PA §3-1 PU 'S 200 CA CU ga- PU u 0 CU 00- u TU I.' N TU 1 0- '—r- —1—' —i— "* '1 Zr In Boli ~ 300 ppm fa In Boli — 20000 ppm TA a 02 c CA OJO Iu ' u <; 0 PA u o u c 210- TU cu PU 0- -XL —I—' Xl '-T- 1 Ca In coli - 23 K In soli — 1200 ppm PU 4 i - CU PA TU PU c TU TA §!• CA Xi PA TA CA H L S2" c o u 10- u 1 0- —i—* —T"1 V In ftoll - 5 ppm Cd In soli — t.9 ppm Figure li Distribution of selected elements in the investigated samples; C • carrot, P - parsley, T - turnip, U - undergioud pait, A - above-ground pmt. 144 Air Pollution Studies by PJXI3 and PIGE Analysis of Lichens S. S'/yin<"/,yk, .1. Kajlns/, and M. Olcch1 /. Itistihttf of liotany, .hii/n linumu Unhu-rsily, Krakom, Poland Lichens are especially sensitive to anthropogenic changes in the environment. Unlike higher plants they accumulate through their surface volatile substances directly from air with- out any filtration mechanisms. Hence they give us environmental pollution levels integrated over the whole period of their growth in contrast to short-term determinations obtained e. g. by means of air pumping through porous fillers. Lichens are available practically everywhere on earth, even in places with severe climate conditions. For a number of years we use PIXE and PICK (Proton Induced X-ray or CJamma-ray Emission) methods for the measurements of concentration of pollutants in lichens. Our experimental arrangement is installed on a proton beam of 2.0 MeV from the small C-48 Kraków cyclotron. We work with ca. 50 200 nA beam currents and the Si(Li) or Ce.(Li) detector distance is 3.5 cm from the target. The beam enters the measuring chamber through a thin Al foil and we keep the air pressure in the chamber on ca. I 2 kl'a in >rde,r to avoid charging effects. The concentrations are calculated by a mulliparaiiieler least, squares fitting program after previous background subtraction. PIXE renders usually data for 20 - 25 elements from S to Pb and by PICE we determine mainly Li, D, F, Na, Mg and Al. Our first results [1,2] demonstrated the value of this method especially for comparative studies of air pollutions on different places and different periods of time. One particular study was devoted to fluorine pollution in the vicinity of an aluminium plant (Skawina, Southern Poland). The obtained V concentrations in selected species of lichens made it possible to draw a map of increased hazard zones and also to evaluate the long-term trends in the area of interest, particularly in the years 1976, 1983 and 1991. Clear dependences on distance, prevailing wind direction and changes in the production of the plant were observed. Examples of results are presented in Table 1. Table 1. Concentrations of fluorine in ppm (mg/kg) units in Physciaadscendens lichen and Orthotrichuiu jnoss from selected sites in the vicinity of the Skawina aluminium plant sampled in the years 1976, 1983 and 1991. 1976 1983 1991 Site Physcia Ortno- Physcia Ortho- Physcia Ortho- No. adscendens t rich u in adscendens Irichum adscendens t rich urn 2 1700 1080 2160 2090 2590 7 600 - 190 290 290 '170 8 650 •i:to 1075 250 700 We observed a decline of the level of V pollution in the year l!)83 (as a result of decreased F omission from the factory) and a further increa-v in 1991 (caused by a new industrial pollution source in this area). In another study we examined anthropogenic changes in the environment of Antarctica (King George Island, South SheUands), mainly lead pollutions in the vicinity of research stations in this area (:$]. f-'tir tliis pnrpust.1 t.raiis|>|ants of lichens from distant, unpolluted regions wore carried out and I ho concentrations \v<>re measured after controlled periods of accumulation times (,i and 12 mouths, respectively). Similar transplantation experiments were carried out (in difforc-ul places in (lie Krakow urlian area., F,xaniples of obtained results are shown in Tal>los 2 and 3. Table 2. Pl> concent rations in Usnea antarctica, ppni. II. Arctowski base, 5 sites at the electricity power station 3 and 12 months alter the transplantation. Site Distance Reference ! months 12 months from road sample after after ĆI, Hi in O.fi 4.8 1, 4 m < 0.2 2.0 14 c 4 in < 0.2 7.2 '20 d 2 m < 0.2 4.0 47 c 2 m < 0.2 5.8 90 Table. 3. Pb concentrations in ppm in llypogymuia physodes in 4 sites (Kl - K4) and Usnoa antarctica in 2 sites (UJ, 1'2) within the city of Krakow one month after transplantation. Material" and sitt?Tl\ iT K2T KM Ul E 18 J4 These results indicate a dean environment on remote places in Antarctica (Pl» content below detection limit) and an immediate increase in pollution level caused by human activity (mainly oil fuelled power stations and heavy transport,). A sharp dependence of the obtained concentrations on the distance and exposure time was observed. These experiments will be continued. The method proves to be Kiim'cjontly sensitive and very useful for long-term comparative studies of both global and local, industrial and traffic air pollutions. The obtained results make it possible to nuggest some standards of admissible, pollution limits for individual elements, based on their concentrations in lichens. References [Ij .]. Kajfosz, S. Szymc/yk, ./. Iftitlioatml. (Item. 58 (19X0) 381. J2] A. '/. llrynkiewic/.. S. Szymczyk, .1. Kaifosz. M. Olech, AW. lush: and Melh. 168 (1980) 517. (3| S. Szymc/.yk. M. Olech, .1. Kajlosz, ./. Railioannl, Clirm. 09 (I!WI) In print. 146 Determination of Trace Elements in Mushrooms using PIXE, NAA and AAS Methods J. Urban, .]. Sieniawski, C. Wilckc1, and D. Hucbuer1 * /. Bezivkshygieneinstilut Dresden, Germany The aim of our work was the following: 1) estimation of heavy metal concentrations in mushrooms (especially wild growing champignons) for the: a) evaluation of their usefulness or harnifulness ;IK a nutritional product, b) determination of their applicability as an environmental pollution indicator, c) investigation of their ability to accumulate increased concentrarions of some elements; 2) evaluation of the applicability of individual analytical methods for the determination of individual elements. In 1991 a. series of mushroom samples from the Dresden area was irradiated by thermal neutrons in the reactor "Ewa" iti Warsaw and results obtained from their NAA (Nuclear Activation) analysis were compared with those of previously made PIXE (Proton Induced X- i ay Emission) and AAS (Atomic Absorption Spectroscopy) analyses. For these three methods the following correlation coefficients were obtained: Table 1. Correlation coefficients for individual elements and the three analytical methods. 1 Fe Cu Zn Se Br Rb Cd "g Pb AAS- PIXE 0.89 0.84 0.04 0.78 0.33 0.98 AAS-NAA 0.92 0.01 0.92 0.86 NAA - PIXE 0.79 0.93 0.87 0.34 0.60 These coefficients are based on results for 12 samples measured by PIXE and AAS, and 6 .samples measured by NAA. Good applicability of the PIXE method was found for the elements Fe, Zn, Se, Br and Pb. PIXE results for Cd are unreliable because of a low detection limit (of ca. 10 ppm). AAS proved to be inapplicable for Se. In autumn 1991 more than 20 samples from Kraków and from the Kielce and Tatra mountains areas with some samples of soil from the same areas were measured by PIXE. We found that: 1) Wild growing champignons accumulate higher concentrations of heavy metals (espe- cially Cd, As, Hg and Pb) than cultivated ones. 2) These concentrations are dependent on locality (soil and environmental conditions) which indicates the applicability of mushrooms as pollution indicators. 3) In champignon we found higher enrichment factors for Ag and Cu than in other fungi. References [I I .).Urban, .1.Sieniawski, C.Wilcke, D.Iluebner: Mushrooms as pollution indicators based on PIXE, AAS and NAA measurements, conf.: Biochemistry, Geochemistry and llydrochem- ixtrti of Environment, Cracow, 02.J2.J991. M7 Mercury and selenium concentrations in human blood by neutron activation analysis W. Mcczyński, L. Glebowa, R. Hajduk, W. M. Kwiatek, B, Rajchel, ,T. Sieniawski, J. Styczeń Mercury and selenium contents in the whole blood were studied using neutron activation analysis. The blood samples were taken from a group of 233 people (70% of females and 33% of males) mostly workers of a mercury discharge lamp factory in Rzeszów, one year after its shut ing down. The blood sample of approximatly 2 ml was drawn from each patient then freezed-dried and homogenised. Approximatly 0.2 - 0.4 g of dried blood was carefully sealed in precleaned quartz ampoule. In a similar manner several standards including Behring Institute and Merck ones were prepared. Samples and standards were exposed to the thermal neutron flux of 1013 n • cm"2 • s"1 for 5 hours in the Warsaw research reactor "Ewa". Irradiated samples were allowed to decay for 20 - 40 days prior to the measurements. Male Female m Total 6 8 10 12 14 Hg concentration (/>cg/L) Figure 1: Distribution of mercury concentration in whole blood. Mercury and selenium concentrations were determined via the decays oflong-lived isotopes 203Hg and 7BSe, respectively. The gamma-ray spectra were measured using 15% germanium detector. The 279.2 keV line intensity was used to determine the mercury concentration after 148 the careful subtraction of the interfering 279.5 keV line intensity of 75Se. Selenium content was calculated using the 264.6 keV line intensity, the absorption thermal neutron cross sections for 20IHg and 74Se and the isotop compositions. Experimantal conditions were good enough to achive as low detection limit as 0.5 ng/L for both elements. The distributions of Hg and Se concentrations are shown in Figs. 1 and 2, For a group of 151 workers the mercury concentration varied from 1 fig/L to 16 pg/L with an average value of 4.9 pq/L\ for 82 samples the concentration were below the detection limit (';hese cases are not inci ided in Fig.l). The values of selenium concentration are widely distributed from 43 ng(L to 199 ng/L arround the mean value of 104 pg/L. Male Female Total 80 120 160 200 Se concentration 0-ig/L) Figure 2: Distribution of selenium concentration in whole blood The values reported here are comparable to the literature data for mercury and selenium contents in whole blood for investigated healthy adults of European countries [1], [2], [3J. References [l] G. V. Iyengar, Biol. Trace Elem. Research 12 (1987) 263. [2] G. V. Iyenger, J. Woittiez, Clin. Chem. 34/3 (1988) 474. [3] R. Van Canwenbergh et al. J. Trace Elem. Electrolytes Health Dis. 4 (1990) 215. 149 Radioactive 125Sb and 60Co in "Ruthenium." Hot Particles from Chernobyl Fallout R. Broda, J.W. Mietelski, J. Sieniawski Radioactive fragments known as "hot particles" identified in Chernobyl fallout have been a subject of detailed investigations through years following the accident [1-6]. Of mainly two kinds of particles observed, the analysis of the more complex "fuel-like" particles pro- vided information on Chernobyl reactor operation, fuel composition and on some aspects of physico-chemical processes taking place during the accident. The other group of particles con- l03 106 tained fairly pure radioactivity of Ru (T,/, = 39.3 d.) and Ru (T,/a = 368 d.) long lived isotopes, but when measured early enough the "Mo (TJ/J = 66 h.) radioactivity could also be detected. Several investigators qualified these "ruthenium" particles as "white inclusions'* [5, 6] known [7] to be formed abundantly within an operating fuel material. However, an- other mechanism has been also suggested [2,4] in which the "ruthenium" particles could have been formed at the time of accident. Hypothetical scenario considers a possibility that some component of the gaseous fraction of evaporated radioactive material was precipitated when penetrating the burning graphite moderator. The volatile oxides of Ru and Mo, reduced or decomposed at high temperatures could be a dominant component of such precipitate. Num- ber of arguments were given [2. 4] to support this hypothesis and the strongest one came from consideration of 106Ru/ Ru isotope ratios. These ratios, characteristic for a history of a given fuel element, did show a broad distribution for ruthenium observed in "fuel-like" particles. In "ruthenium" particles the distribution, although centered around the same av- erage value, was significantly narrower indicating partial mixing of ruthenium radioactivity originating from various fuel rods. Approximately 5.5 years after Chernobyl accident we remeasured the gamma radioactiv- ity of 20 previously analysed "ruthenium" particles, in order to search for other long-lived radioactive components. As expected after this long decay time, the previously predominant radioactivity of 103Ru was absent, and the 106Ru activity was reduced since accident time by factor more than 40. In the measured spectra apart from residual 108Ru radioactivity one 125 eo could easily recognize gamma lines from Sb ( T1/2 = 2.73 a.) and Co (T^j = 5.3 a.). Figure 1 shows an example of gamma-spectrum measured for a particle, where the 125Sb and 60Co components were relatively more abundant. The quantitative analysis gave for each measured particle the acivity of l26Sb and 60Co relative to the main 1O0Ru activity. Corrected for decay to 26th April 1C86 accidents date and normalized to the total 103Ru + 106Ru acivity deduced from the known Ru isotope ratio, the fractions of 12BSb activity were1 ranging from 0.14-10"3 to 1.9-10"3 . This is to be compared with somwhat higher value of 3>10~3 expected in the, on average 570 days [2] operating, reactor fuel. The corresponding fractions of C0Co activity were order of magnitude smaller reaching at most the value 3.2>10"~4, but beyond detection limit in some particles. For '26Sb and C0Co activity no correlation was established neither with the particles total activity nor with Ru isotope ratios. Both antimony and cobalt were not detected earlier in "white inclusions". Rather low boiling point (175O°C) for fission product-antimony, and likely outside of reactor fuel origin of cobalt puts both observed radioactivities into category of components, which could precipitate from the gaseous fraction. Thus, the observation of Sb and Co radioactivity in "ruthenium" hot particles provides new argument supporting hypothesis, that these particles were formed outside of fuel rods in physico-chemical processes at the time of accident. 150 10 Energy e h Example of gamma-spectrum measured for a particle, where the 125Sb and 60Co components were relatively more abundant References [1] L.Devell et al- Nature 321 (1986), 192. [2] R.Broda - Ada Phys. Pol. B18 (1987), 935. [3] Proc. Int. Workshop on Hot Particles from Chernobyl Fallout, October 1987, Theurn, FRG [4] R.Broda, B.Kubica, Z.Szeglowski, K.Zuber - Radiochimica Acta 48 (1989), 89. [5] E.Piasecki, P.Jaracz, S.Mirowski - J. of Rad. and Nuci. Chem., L. 141 No 2 (1990), 221. [6] P.Jaracz, E.Piasecki, S.Mirowski, Z.Wilhelmi - ,/. of Rad. and Nuci Chem., L. , 141 No 2(1990), 243. [7] H.Kleykamp, J.O.Paschoal, R.Pejsa, F.Thatmmer - J.Nuctear Mat. 130 (1985) 426. 151 A Detector for Evaporation Residua in Coincidence with Gamma Quanta W. Męczyński, M. Janicki, J. Grębosz, J.Styczeń, J. Heese1, K.H. Maier1, H. Grave1, H. Kiuge1, M. Schramm1, R. Schubart1 A detector for evaporation residua to work in coincidence with gamma quanta detected with the OSIRIS array has been constructed in our laboratory and mouated on the beam line of VICKSI in HMI. It consists of 2 concentric rings of 6 and 12 cilindiical detection elements, respectively, placed arround a central hole to let the beam pass through, at 70 cm distance behind the target. This detector covers the range of 12°, except of 2° opening of the central hole. Channel Fig.l: Portions of singles gamma (a) and gamma-recoil coincidence (b) spectra from 185 MeV i0Ar on l*2Sm. 152 139 Each of the 18 detection elements contains a thia aluminium foil (ling/cm2) of 6cm diam- eter A nucleus hitting this foil knocks out electrons that are accelerated and focused by 20 kV onto a smaH thin plastic scintillate* (10/un PILOT U). The number of emitted electrons is proportional to the energy loss of the nuclei and therefore the signal from the heavy and slow recoiling nuctei is larger than from any background particles oi ions. Evaporation residua are in addition (and principally) identified by time of flight, which differs them well from scat- tered beam and fission products. The detector is fast eno igh (10 ns double pulse resolution), allowing the evaporation residua to be detected, even thitt scattered beam particles intensly bit the detector. The granularity of the detector and the measured /ecoil velocity allow to correct for Doppler shifts. As this detector needs only a narrow forward cone, th« inner ball of the OSIRIS array can still be used with its 48 elements; the most forward Ge - detector however has to be removed. Measured.are f-f coincidences, evaporation residua, gauuna energy sum and multiplicity. Clean gamma-spectra, frfe of thr fission process and Coulomb excitation etc., can be obtained with the use of the detector. It -wes tested using 185 MeV i0Ar beam on 680 pg/cma l6*Sm and 1.4 mg/cm2 l2iSn targeta. The total detection efficiency as high as 30% for evaporation residua was achived. In gamma-recoil coincidence spectrum a peak to background ration was improved by a factor of 4 (see Fig. 1). Spectroscopy of light lead isotopes is proposed with this new detection system. HMI, Berlin. Testing of a BGO scinfcillator for high-energy gamma-ray detection II'.hnilns, I'.lUriiiurrzyjk, H.h'mim/, A.Mnj, W.MtjCzyiiski, J.Styczeń, M.Zięblimki In this note series of lests ami measurements an.1 described, which were undertaken to investigate the characteristics of a large volume bismuth gennanate (IKiO) detector available: from l.nlxniilori Nti;ii>nuli iii l>cijtium. Such detectors are known as suitable for the detection of gamma rays of energies above 1(1 MeV (Ij. Main feature of the IKiO (lli,| The measured values for the energy resolution of the investigated detector are, plotted in fig. 1 at; a function of the gamma-ray energy. A leant-s<|tiiire lit to these data gives the k factor (see ff|. I) e<|ual to 0.112 MeVl/2, -i -Trrrn c 0 10 0 w (L) 5 ierg ; • 1 ^ 1 . 1 1 1 . I ,.>. 1 .J • 1 t t o I 0 fi 1 2 5 ID yo 50 100 i - r.>y eii<'i-^y |MfVj rt- I: I'/X])erimentally measured energy resolution for the I3G0 detector as a function of I he giimuia ray energy. Tin.- response hind ion of the l" X I" M(l() detector for high-energy gamma radiation was calculated [•!] using the code d'AVt/VV [.r»], taking into account the dependence of the energy resolution of the detector on the gamma ray energy. The results of such calculations were compared to high-energy gamma spectra from the "H(p,-))I2C reaction measured at fi.'l5 MeV protons from the InnliluU t>}' Kiichur f'hysii:* cyclotron. This reaction if often used for calibration of gamma-ray detectors in high-energy range [(>]. It populates the resonance in riC, located around "ill MeV, which decays lo I he ground and (irsl excited states by emission of gam ma-rays of two energies eipial l<> A.'.. •-. /;,.,„ )• Q {2I.H and 17.1 MeV respectively, in case of the above slated beam energy). 154 The tnmpcratiiru dependence of the detector gain wafl checked in the room-temperature rang«. 'L'lic temperature of th« crystal was measured using a thermocouple. The linear energy calibration coefficient. A\ {E - AQ 4- A\ * channel) dependence on the detector temperature was established. It was found that the detector gain is quite sensitive to temperature changes. A new energy calibration method for BGO detectors in the high-energy range {E-, > 5 MeV) was used. It is based on the response of bismuth germanate to neutrons. An energy spectrum measured using the BGO detector during irradiation of the scintillator crystal by slow neutrons from a neutron source is shown in fig. 2. Two 7.42 and 10.20 MeV lines from thermal neutron capture in two germanium isotopes of the BGO crystal (70Ge and 73Ge respectively) are seen. It is proposed to use these lines for the calibration of the detector. 105 m C J O 104 103 BGO 4"x4' 102 0 12 3 4 5 6 7 B 11 12 energy [MeV] l-'ujnrr. 2: The BGO response to neutrons from the polonium-beryllium source. The energy calibration in based on 1.17, 1.33 and 2.50 (sum peak) gamma lined from a weak fi0Co source measured simultaneously. References [1] D.M.Drake, L.R.Nilsson, J.Faticett, Nvcl. Instr. and Methods 188 (1981) 313 (2) Harshaw Radiation Detectors Catalog, 1984 [3] W.R.Leo, Techniques for Nuclear and I'nrtkle Physics Ei-jmrimcnis, Springer Vorlag, Berlin 1987 [A] F.damera, privalr communication [f>| UKANT3, CEtlti "port, DD/EE/84-1 [*;) M.T.C.iHins, S.MHIIHIOS, N.ll.Roberson, A.M.Sandorfi, M.H..VVi.|ki. I'liy*. Rev. 155 Monitoring Electronics During the Experiments with the OSIRIS (HMI Berlin) Jerzy Grębosz OStlUS is a multidetccior .system installed in Halm-Meitner Institute in Berlin (Germany). Our Krakow's group (The Nuclear Structure Lab of the Nuclear Specuoscopy Departament) participates in developing this system (vide: report about the recoil detector), and in the experiments on it. OSIRIS electronics is controlled by the computer. Before experiment it could be setup using a handy window system. The status of the electronics could be saved on the disk and restored later. This software (called "ECL") existed earlier and was written by Frank Meyer (IKP-Cologne). CERBERUS is a new software for watching and testing the state of this electronics around the OSIRIS during (he time of the experiment. This program allows a flexible way of checking the chosen points of the. electronics. The user can define his own signals to be monitored continously. CERBERUS works on the ATARI ST computer connected to the VME bus by the DMA port. VME bus is connected to the CAMAC. The communication routines were used from the program ECL. The reason of designing CERBERUS was to prevent collecting nonsense data when something goes wrong with the electronics, although not so wrong, to be noticed by the experimentalist at once. To perform the monitoring - the user has to connect the desired signals to the four CAMAC Le CROY 4413 sealers. Typically these are signals from germanium detectors, BGO ball elements, shields, the beam etc. In total 128 signals like (hat can be connected. Then the configuration should be set. The data signals to be watched often belong to the same category (for instance 12 signals of the germanium detectors). CERBERUS watches them separately, and can also watch how this cathegory (group) behaves in general. To set the configuration - means to assign the channel to a group, and to define the alarm conditions. 156 QD-QDv Steps of presorting In practice, the sort and presort are realized by several programs which make the whole thing in steps. 1) Simplifying - e.g. creating the tape which has the structure independent of the data acquisition system. At this time the projections of every ADC are also made. (Additionally, the newest version of the program can produce a special group of time-of-flight spectra. Each of them dedicated to one recoil detector element. All mentioned spectra are used to make the calibra- tion of each ADC. This is needed for the recalibration.) 2) Presorting itself. The tape is read and every event is recalibrated and stored on a huge disk file (ca. 1 Giga B). 3) Collecting. Rading the parts of the file and putting them in the specific order on the output EXABYTE tape. The events on this tape are already presorted. 4) Sorting. To do this - a special program has been written. It can sort simuitainously to 4 matrices . The program contains the part which can be modified by the user to make his own, special way of sorting. It is written in "C-)anguage", but it has an easy syntax for the FORTRAN-Iovers (obtained by macro definitions). This software has recently been used for the data evaluation in two "classical" OSIRIS experiments, then modified for the recoil detector experiments. The software is written to work under VMS operating system. That's why it can be used to work on experimental data not only in Berlin (as FASTSORT !), but in Krakow as well. 157 Pre-sort and sort of OSIRIS' y - y coincidence data onto 2 - dimensional matrices. Jerzy Grębosz The experimental data from the OSIRIS' experiments are collected on the EXABYTE cassettes. These are raw data of the type: "event-by-event". After the experiment the data have to be sorted onto y~Y coincidence matrices. Such a process of sorting is usually time consuming and requires a big memory. Till now in Hahn-Meitner Institute (Berlin) this sorting was made using the FASTSORT system. It is a stand-alone computer system designed to sort data stored on an optical disk. 3 Years ago it was modified to sort data from the EXABYTE cassettes. FASTSORT didn't satisfy the users, because in many aspects was clumsy, and the designer refused to modify it any more. FASTSORT was completely unable to handle the new type of data - e.g. the recoil detector's experiment data. Last but not least - FASTSORT was available only in Berlin and after the experiment data couldn't be sorted in Krakow. To sort raw data onto coincidence matrix a lot of memory is needed. (The 4Kx 4K matrix requires 32 MB). There is no problem if we have this memory available, but it is impossible to have such memory on VAX. In such a case the matrix has to be kept on the disk. This requires hundreds of millions read/write operations. This makes the whole thing unacceptable, because it is time consuming. To make it acceptable, the raw data from the EXABYTE cassette have to be rearranged before sorting. This rearrangement is called: presort. The idea of presorting is to create another EXABYTE cassette where events are in such an order that to sort them we need only 256 read/write operations. What does it mean precisely? The raw data tapes are created during the experiment collecting event-by- event on the tape. Having 3 events: 700,250; 6000, 1000; 20,4000; After presorting events are reordered to : 20, 4000; 700, 250; 6000; 1000 So they are sorted according to the first data in the event. Such a presorted tape can be used later for the traditional matrix sorting what is much faster now. 158 C A M A C * łfcłi^ł-Słłr; CAMAC C A M A C • CAMAC : ., ., driver Connection of the hardware i liiLBIiRUS lets the sealers run for a certain length of acquisition time. After this time it cads out (ill 128 channels of sealers. This is one measurment. The first 10 mensure- ii..-ins we used to define the "normal state". AI if! this, the normal process of the monitoring starts. Let's assume that we defined an ;il;uin level ;is 50%. The following things are from now on constantly checked: - The current ratio of single channel to the current average of Us group. If this ratio differs more than 50% of the initial one - the alarm will he produced. • The current ratio or the single group average lo the average of all 128 channels. Tlu: difference more than 50% will make the alarm t'otb <>f this checks are performed lo look if something is changing in a unexpected way • iH'.l - if so - to alarm the experimenlisl. The alarm is Iransmited from the experimental li;-,ll to the measuring room. Additional)', on ihe computer screen Hie messages can be .:•• i n, explaining the place where something strange happens. During the configuration i i is possiMe lo define the mnemonic names of tin; every single channel. So CERBERUS i,il! s lo the user in a "human" language. y, in the program have hcen implemented routines for handling the signals •iininu from the 18 recoil detector elements. Il is performed by programming a special "'..VMVIAC array. The recoil detector signals ;\iv coded, and the code can be chosen by the .. ..prriniefiialisf -• Such coding allows collecting this new type of dala by the existing data i' >.ji i j --i I i-) r) .system. Readout Controller for Fast Encoding and Readout ADC's Mirosław Ziębliński The readout controller - FDT32 module has been constructed for data transfer in the data acqusition system designed for the EUROGAM multidetector array.In phase I this array will consist of a set of 45 Ge detectors surrounded by individual BGO shields and will be operating in Daresbury. In the phase II it will be upgraded to 75 Ge and will be operating in CRN-Strasbourg. Several experiments on that array have been proposed with participation of Cracow's physicist. The EUROGAM array data acqusition system is distributed to several VXI and VME crates connected with the Ethernet network. The data, filtered by the trigger, are read and sent via a 32 bits ECL DT32 bus to the Event Builder VME crate. The system has been designed to handle high data rates. (The first implementation will provide about 6 MB/sec on the input to the Event Builder.) The designed FDT32 is a CAMAC module which allows for using of various CAMAC Fast Encoding and Readout ADC's (e.g. LeCroy 4300). The main features of the FDT32 module are: * communication with the CAMAC ADC's via FERA bus, * access to EUROGAM DT32 bus, * FIFO and LOOKUP memory for data from the ADC's, * software controlled timing for ADC GATE (delay and length), * CAMAC bus controlled. The FDT32 module provides control signals and data readout by FERA bus from the full crate of the CAMAC modules. Two buses are used: one for the control and the other for the data transfer. The control signals for FERA bus module are the differential ECL signals, while the data signals are single-ended ECL. On the EUROGAM DT32 bus, the FDT32 module works with 36 differential ECL lines. The 32 lines are used for the data transfer and the other 4 are used for the control. Several FDT32 units may be daisy-chained to transfer data from the CAMAC crates to the Event Builder crate. The FDT32 module contains six blocks in order to ensure: i) complete readout of the ADC's, ii) data transfer to the DT32, Hi) connection to the Master Trigger, iv) other CAMAC functions. The blocks are: • the Master Trigger interface, • the FERA bus readout interface, • the data FIFO for storage and conversion of subevents, • the DT32 interface, • the CAMAC interface for control and check of the FDT32 by the CAMAC bus, • the main control and control signal multiplexers as well as test registers . 160 Publications 1 • Zyb«r_K., Balouka D., Beck F. A., Byrski T., Ciirien D., Duchene G., Gehringer C, Haas B., Mordinger J.C., Romain P.t Santos D., Styczeń J., Vivien J.P. Dudek J., Szymański Z., Werner T.R.. "A Comparative Study of Superdeformation in 148,147,148^. p08Sjbie Manifesta- tion of the Pseudo-5C/3 Symmetry, Octupole Shape Susceptibility and Deep-hole Excitations" Phys. Lett. B 254 (1991) 308 2. Piiparinen M., Nagai Y., Kleinheinz P., Bosca M.C., Rubio B., Lacli M.. Blomqvist J. "T'hree-nucleon Yrast States in HB5m". Z. Phys. A 338 (1991) 417 3. Łach M., Kleinheinz P., Piiparinen M., Ogawa M., Lunardi S., Bosca M.C., Styczeń J., Blomqvist J. "Multiparticle - and Particle ® Octupole States in 149T6". Z. Phys. A 341 (1991)25 4. Alber D., Alfier R., Bach 0., Fossan D.B., Grawe II., Kluge H., Lach M., Maier K.H., Schramm M., Scliubart R., Waring M., Wood L., Huebel H., Jing-ye Zhang. "Quadrapole and Octupole Collectivity in Light Po Isotopes". Z. Phys. A 339 (1991) 225 5. Jensen H.J., Hagemann G.B., Tj0m P., Frauendorf S., Atac A., Bergstr0m M., Bracco A., Brockstedt A., Carlsson., Ekstr0m P., Espino J.M., Herskind b., Ingebretsen F., Jongman J., Leoni S., Lieder R.M., Łonnroth T., Maj A., Million BM Nordlund A., Nyberg J., Piiparinen ML, Ryde II., Sugawara M., Virtanen A. Interaction Strength and Shape Difference for the m Ziyyj and hiX/2 Configurations in Tm". Z. Phys. A 340 (1991) 351 6. Zganjar E.F., Kortelahti M.O., Wood J.L., Bingham C.R., Careter H.K., Toth K.S., Hamilton J.H., Konnicki J.. Chaturvedi L., Newbold W.B. "Shape Coexistance in ™°Hg" Phys. Rev. C 43 (1991) 484 7. Chaturvedi L., Zhao X., Ramayya A.V., Hamilton J.H., Kormicki J., Zhu S., Girit C, Xie H., Gao W.B., Jiang J.R., Petrovici A., Sdunid K.W., Faessle A., Johnson N.R., Baktash C, Lee T.Y., McGowan F.K., Halbert M.L., Riley M.A., McNeill J.H., Kortelahti M.O., Cole J.D., Piercy R.B., Jin H.Q. "Test of Microscopic Calculation of Multiple Band Structures and Large Deformations in a8Ge and72 Se" Phys. Rev. C 43 (1991) 2541 8. Bingham C.R., Kassim M.B., Zhang M., Toth K.S., Akovali Y.A., Hamilton W.D., Carter H.K., Kormicki J.. Schwarzenberg J., Jarrio M. "Identification of 185Pt Alpha Activity and Study of neAu Alpha Decay" Phys. Rev. C 44 (1991) 1208 9. W.Meierkord, Bliimke T., Briissermann M., Hofste J., Menzebach H.U., Pennings J.F., Stachura Z., Vollmer W., Wigger J., CleffB. "p3/2-Alignment Following Heavy Ion Impact" Z. Phys. D 18 (1991) 75 10. W.Meierkord, Bliimke T., Hofste J., Menzebach H.U., Pennings J.F., Stachura Z.. Vollmer W., Cleff B. "M3-Alignment of Gold Followbg 0.2-5.0 MeV Proton Impact Ioniza- tion" Z. Phys. D 21 (1991) 131 11. Mokler P.H., Stohllcer Th., Kozhuharov C, Stachura Z., Warczak A. "Radiative Elec- tron Capture: A Tool for Structure Studies of Heavy Few-Electron Ions" Z. Phys. D 21 (1991) 197 12. Hrynkiewicz A., Królas K., Wodniecki P. "Application of Perturbed Angular Cor- relations to Studies of Impurity Complex Formation in Metals" Struct. Chem., Vol. 2, I>p.(249)457-(262)470, VCH Publishers 1991. 13. Decoster P., De Doncker G., Rots M., Hrynkiewicz A. "Indium-impurity interactions in ft nickel host", J.Vhys.-.Condens.Matter 3(1991)7575-7586, IOP Publishing 1991 11. Wndniccki P., Wodniecka B., Marszałek M. "Perturbed Angular Correlation Experi- ni(!!its on "'TTJ in Oxidized AgCd Alloy" Hyperfine Interactions^2 (1991) 301 1.61 I!'. Tiimldnviiv. /,., lujdm K., S/,y!.iiln A., lifijorolt A., linhtnda M., Kiurx |{,. Kruk It, '/.VJ;HI'MII A "Sii|n-iri»inlw-iivii,y in die ((.'(l|..x I'l'a.'iiiiij C!»s 67...^ System'* Physika C 174 Ifi. I'rv/."!: I'!., Itfv/,«• k .1., ''Study «>I" loririatinn enthalpies of a single vacancy in a one diluent mital MililaUire ul Ale inns in /( vanadium oxide lirorize". Pliy.'i. Slat. Sol. A. J.2B ("10.M) |«. ;m. 17. Hry.-.-k J., \Vi 18, H.nciui/dwuser K., ,'w'jiii.'! H., Mir/.lto B, "D«l,«nninuhiejicss of \\w lloilurnd Frequencies Irum lli )•>. Hiicii'.Milianct K., Scpiol !!., Miczko li, "Mossl>;vu«r Sludy of Iron Difi'nsiou in T'oryl- limn" i'livsiri. U 5 (IB (I'.MH) IS!)" :i(l. <;'.l)!.5r.w;i,i\\,, 1/M-fV! (:..;.)''., Van GrioluMi R-, OieiT.k.l. "STTM fnvestignlion of T,asi'i Mi- cr •.-!!. !!':iuli <:;., Nn^mt. K.A., CivoU-waM., Saint A., Lcr;gc G..1.F. "Sub-Micron ST1M Tocnuumphy li^coiisUiirijtin Tcr.lniiqucs", Nncl. lustrum, and Mul.h. B 54 (1991.) 390 22. f :ii..)k:vva IvL, iirndi C, Saint A., Lc^e GJ.F. "High Resolution Channeling STIM." Nur), lnsfrnin. juid Mi>th. B R4. (19!M)31)7 2.r{. f;'hoh".v.i !V|., [.Juiicli C, Kirhy B., U'.gge G..I.F. "Damage in Organic Materials Using •M-..-!i!iiiiij; P.ui.icic Mi(rf>l)Rf«as." Nud. Inslrmn. ami Metli. B 54 (J901)101 '.'•I. Li [viiurjk'.u, /.lin Jinj'dt;, 7A\n .lioqing, Zhou ZJicng, Iinang Zegi, Zhou Vv'ciyinj?, • hii'^r.-i iM., u'"Ąi',': (!.l.F. "Elemental ituips of Amoeba proteins by ,1 Scanning Proton Mi- rin|iii!lic", Nurl. luKiruui. and Moth. B 54 (1991) J5C •1\\. Kj,i»(. A., B»:m-h G.S., QufeiJM., Dooley S I n- ..u D.N., Ivcgge G.J.F. "High i!n;;ui!ilion 'JVcimiqncs for the Scantling Prolcm 'r '-i Jrnin. aucl Mcth. B .'..'i/.'i? (l(ł!M )7(? ( -<>• . ,L')i5jv\-.'..M.:. B'-urh G.fj., Sninl. A., Loggc G.J.F., Wieluński I-. "v^: jiolin;; .STK/l ('iraauini;; Tvan^inissioii Ion Microscopy)", Nuci. lnsl.nitn. iiB/5T .1 •• 5.0-viibi*U;>iiB fco Conferences 1. Hrufia i{. "Nev/ and Old Sn fsomers Produced in Heavy-Ion Collision!;'1 .! •'(OK-flbigs of Piaski/jMiltoiajki Int.. Scliool on Physics, September 1991. (L991) 2. Zii;uł« r:.T.,15rodą.!i,, CollaU It, Mcncgazzo R., Klcinlicin/. P., LadriJVl., Maier K.I!.. tirawt! M., Srliuli.'irt R., Schraimn M. "Energy Inversion of tlie f7j-L and li$j2 Neutrons in Vrnsl ConligurnUoris nt^Vb**", DPG Salzburg 1092, (1991) 3. Mijczyi'iski W., Zuher K., Brtnla )!.., Mcncgazzo It, Kleinheinz P., Bo<;ca M.G., P»rir- z + 1!!) P., Liang C.F.jllJloniqvist; J. "Directional Polarization or the (x/i n/2) 0 Pair in the Dt/ Ground State from a Study of its GT-Decay", DPG Darmstadt (199J) 491 4. Waring M., Dar.h ('., Fossn.n D.U., Gvawo. Jl., II.ce.se. .1., Kluge H., Lad). JVT., Lahmcr W., M;iicr K.1L, Sdirau\ui M., Srhuhnrt It, Wood L.D. "Spuctroscopy of IP8Po as\(l the onset of Collectivity", DPG-Darmstadl. > 162 5. Maj A,, Gaardhøje J.J, Herskind B., Nyberg J., Sletten G., Bracco A., Million B., Pignanelli M., "Mapping the Shapes of Hot l67Yb Nuclei", Understanding the Variety of Nuclear Excitations ed. A. Covello, World Scientific Publishing Company (1991) 703 6. Piiparinen M., Kleinheinz P., Lunardi S., M§czyński W., De Angelis G., Ogawa M., Soramel F., Blomqvist J. "One - and Two-Phonon Octupole States in U7Gd and UBGd", DPG Darmstadt (1991) 490 7. Schramm M., Grawe H., Grgbosz i., Heese J., Kluege H., Maier K.H., Schitbart R. "Gamma-Spectroscopy of 2O8P6 with Heavy Ion Transfer Reactions", DPG - Salzburg 1992 (1991) 8. Schubart R., Alber D., Grawe H.,Grçbosz J., Heese J., Kluege H., Maier K.H., Schramm M., Fossan D.B., Kaubier L., Rotter H. "In Beam Spectroscopy and Shell Model Structure of Exotic Nuclei Close to 100Sn", DPG, Salzburg '92 (1991) 9. Deng J.K., Hamilton J.H., Ramayya A.V., Ma W.C., Zhao X., Kormicki J.. Severijns N., Vanenste L., Hamilton W.D., Mantica P.F., Carter H.K. "On-Line Nuclear Orientation of 7OJ4S", Proc. Second Int. Conf. on On-Line Nuclear Orientation and Related Topics, Oak Ridge, October 1991. (1991) 10. Buttler-Moore K., Hamilton J.H., Ramayya A.V., Deng J.K., Kormicki J.T Ma W.C., Mantica P.F., Carter H.K., Piercy R.B., Morgan J.C., Hamilton W.D. "Off-Line Nuclear Orientation Studies of e6Mo", Proc. 2nd Int. Conf. on On-Line Nucl. Orientation and Related Topics, Oak Ridge, October 1991. (1991) 11. Alton G.D., Carter H.K., Jones CM-Kormicki J.. Olsen D.K. "Element/Target De- pendent Release Times and Release Efficiences for the Proposed OREB Facility", Second Int. Conf. on Radioactive Nuclear Beams, Louvain-la-Neuvc, Belgium, August 1991. (1991) 12. Ma W.C., Hamilton J.H., Ramayya A.V., Jiang J.R., Chaturvedi L., Kormicld J.. Zhao X.W., Gao W.B., Xie H., Johnson N.R., Baktash C, Lee I.Y., McGowan F.K., McNeil J.H. "Band Build on High K Isomer in Near Spherical Nucleus l86Hg", Bull. Am. Phys. Soc, 6 (1991) 1378 13. Lach M.. Kleinheinz P., Styczeń J., Ogawa M., Piiparinen M., Lunardi S., BoscaM.C, Blomqvist J. "Multiparticle - and Particle Octupole States in 149Tb", DPG Darmstadt 1991, p. 491. 14. Stöhlker Th., Kozhuharov C, Mokier P.H., Bernstein E.M., Warczak A., Stachura Z. "Strahlender Elektroneneinfang in Wenig-Elektronen-Systeme", Arbeitstagung über En- ergiereiche Atomare Stöße, ed. by B. Fridce et al., Riezlern (Austria), EAS-12 (1991) 31 15. Stöhlker Th., Kozhuharov C, Livingston E.A., Mokier P.H., Stachura Z., Szymański Z., Warczak A. "Evidence for Resonant Double Electron Capture and Single Excitation in Ge31+-Ne Collisions", Proc. of IV-th Workshop on High Energy Ion-Atom Collisions, Bu- dapest, ed. by H. Araki et al., Lecture Notes in Physics, 370 (1991) 117 16. Mgczynski W., Rajchel B., Glebowa L.. Hajduk R., Kwiatek W., Sieniawski J., Styczeń J. "Mercury and Selenium Concentration in Human Blood by Neutron Activation Analysis"~ 5th Meeting on Nuclear Analytical Methods, Dresden, 13-17 May 1991., Abstract (1991)17 17. Hrynkiewicz A. "Znaczenie energetyld jądrowej dla poprawy stanu środowiska natu- ralnego", VII Konferencja "Zagadnienia surowców energetycznych w gospodarce krajowej", na temat "Gospodarka surowcami energetycznymi w warunkach przejścia do gospodarki rynkowej", Kraków - Osieczany 26 - 28 czerwca 1991 18. Szymczyk S., Olech M., Kajfosz J. "Air Pollution Studies by PIXE Analysis of Lichens", 5-th Meeting on Nucl. Analytical Methods - Dresden, 13-17 May 1991. (1991) 163 19. Szymczyk S., Kajfasz J., Urban J., Śtiwiński S., Przybylowica W. "PUCE Analysis of Trace Elements in Carbonate Rocks and Harite" European Conf. "Physics for Industry - Industry for Physics", Krakow, 17-19 Sept. 1901. (1991) > 20. Olech M., Szymczyk S., Kajfasz J. "Air Pollution Studies by PIXE Analysis of Antarc- tic Lichens", Int. Conf. on "Antarctic Science - Global Concern" - Bremenhafen, 23-27 Sept. 1991. (1991) 21. Szymczyk S., Kajfosz J., Olech M. Lokalne zanieczyszczenia ołowiem środowiska w re- jonie Antarktyki. "Geochemiczne, Hydrochemiczne i Biochemiczne zmiany Środowiska przy- rodniczego na obszarach objętych antropopresja - analiza stanu, prognozowanie i zapobie- ganie", Sympozjum AGH, Kraków, 2 grudnia 1991. (1991) 22. Kwiatek W.M. "Zastosowanie promieniowania synclirotronowego do analiz pierwiastkw śladowych", I Krajowe Sympozjum Użytkowników Promieniowania Syn- chrotronowego, Kraków, 11-12 lutego 1991. (1991) 23. Kwiatek W.M. "Selected Applications of Synchrotron Radiation", XXVI Zakopane School of Physics, May 1991. 24. Kwiatek W.M., Cichocki T., Galka M., Paluszkiewicz C. "Microanalysis Using Syn- chrotron Radiation", II European Conf. on Accelerators in Applied Research and Technology, Frankfurt, 3-7 Sept. 1991. 25. Kwiatek W.M., Lekki J., Paluszkiewicz C, Preikschas N. "Application of FTIR, PIXE and RBS for Trace Element Analysis in Biological Samples", X Int. Conf. in Ion Beam Analysis - Eindhoven, 1-5 July 1991. (1991) 26. Wodniecki P., Corts Th., Uhrmacher M., Lieb K.P., "PAC-Studien zur Amor- phisierung von Ni/Ti-Mehrfaschichten durch Ionenstrahlmischen mit Xe-ionen", Tagung der Deutschen Phys. Gesellschaft (1991) 27. Urban J., Szymczyk S., Wilcke C., Huebner D. "Comparison of Results from AAS and PIXE Methods", 5th Meeting on Nuclear Analytical Methods - Dresden, 13-17 May 1991. 28. Wyszondrski P., Przybylowicz W.,Szymczyk S. "PIGE as a Useful Method of Flu- orine Determination in Kaolins", European Conference "Physics for Industry - Industry for Physics", Krakow, 17 - 19 September 1991. 29. Wyszomirski P., Urban J., Szymczyk S., "Fluorine in Raw and Fired Polish Clays - an Example of Application of the PIGE Method", European Conference "Physics for Industry - Industry for Physics", Kraków, 17 - 19 September 1991. 30. Dutkiewicz E., Van Kuijen W.J.P., Munnik F., Mutsaers P.H.A., Rokita E., De Voigt M.J.A. "Determination of Hg Concentrations in Gasses by PIXE", II European Conference on Accelerators in Applied Research and Technology, Frankfurt, 3 - 7 September 1991. 31. Urban J., Sieniawski J., Wilcke C. "Grzyby jako wskaźniki zanieczyszczenia środowiska na podstawie pomiarów PIXE i NAA", "Geochemiczne, hydrochemiczne i bio- chemiczne zmiany środowiska przyrodni czego na obszarach objętych antropopresja - analiza stanu, prognozowanie i zapobieganie" - AGH Kraków, 2 grudnia 1991. 32. Wyszomirski P., Urban J., "Fluor w krajowych iłach ceramicznych i jego emisja pod- czas wypalania", "Geochemiczne, hydrochemiczne i biochemiczne zmiany środowiska przyrod- niczego na obszarach objętych antropopresja - analiza stanu, prognozowanie i zapobieganie" - AGH, Kraków, 2 grudnia 1991. 33. Dutkiewicz E.M., Godzik B., "Pomiar zawartości wybranych metali w roślinach - porównanie metod AAS, NAA i PIXE", "Geochemiczne, hydrochemiczne i biochemiczne zmi- any środowiska przyrodniczego na obszarach objętych antropopresja - analiza stanu, progno- zowanie i zapobieganie" - AGH, Kraków, 2 grudnia 1991. 164 34. Stilton S.R., .Cholcwą_M,, Bench G., Sainl A., Legge G.J.F., Weirup ' ••!• ' "Sriuming Transmission Ion Microscopy (STIM): A new Technique for D« n , .."uppmg ol Micrometeoril.es", Presented at 22nd Lunar and Planetary Science Conference, Huston, Texas, USA, March 18-22, 1991. Published in Lunar and Planetary Science XXII, ed. by Lunar and Planetary Institute. 35. Leggc G.J.F., Saint A., Bench G.,Chulewa M., Allan G.L., Laird J. "The Evolution of Biological Techniques on the Proton Microprobe", Presented at Int. Conf. on Scanning Microscopy, Bethesda, MD, USA, May 4-9, 1991. 36. Cholewa M., Legge G.J.F., Weigold II., Holan G., Birch C. "The use of a Scanning Proton Microprobe in AIDS research", Presented at 7th Australian Conference on Nuclear Techniques of Analysis, The University of Melbourne, Melbourne, Victoria, Australia, Nov. 20-22, 1991. Proceedings ISSN 0811-9422 (1991) 185. 37. Bench G., Saint A., Cholewa M., Legge G.J.F. "Three Dimensional STIM Tomogra- phy", Presented at 7th Australian Conference on Nuclear Techniques of Analysis, The Uni- versity of Melbourne, Melbourne, Victoria, Australia, Nov. 20-22, 1991. Proceedings ISSN 0811-9422 (1991) 6. 38. Antolak A.J., Pontau A.E., Morse D.H., Weirup D.L., Cholewa M., Bench G., Legge G.J.F. "Ion Microtomography (IMT) and Particle-Induced X-ray Emission (PIXE) Analysis of Direct Drive Inertial Confinement Fusion (ICF) Targets", Presented at Inertial Confinment Fusion Targets Characterisation Meeting, Albuquerque, New Mexico, U.S.A., Sept. 23-26, 1991. 39. Legge G.J.F., Saint A., Bench G., Laird J., Cholewa M. "Ion Beams as high resolution probes of structure and function", Presented at 10th Int. Conf. on Ion Beam Analysis, Eindhoven, The Netherlands, July 1-5, 1991. 40. Bench GM Saint A., Cholewa M-, Legge G.J.F. "STIM Tomography: A Three Dimen- sional High Resolution Imaging Tool", Presented at 2nd European Conf. on Accelerators in Applied Research and Technology (ECAART), Frankfui't, Germany, Sept. 3:7, 1991, Reports 1. Collatz R., Kleinheinz P., Menegazzo R., Broda R., Zhang C.T., Blomqvist J., Rico J., Gadea A., "Gamow-Teller Decay of 148T6". IK?, KFA Julich Annual Report 1990 (1991) 25 2. Santos D., Balouka D., Beck F.A., Byrski Th., Curien D., Duchene G., De France G., Haas B., Kreirev A.J., Merdinger J.C., Vivien J.P., Zuber K. "Structures Rotationelles dans le Noyau Doublement Impair Tres Deficient en Neutron 172Re". Rapport D'Activite CRN, Strasbourg 1991 (1991) 3. Stohlker Th., Kozhuharov C, Livingston E.A., Mokier P.H., Stachura Z.,Warczak A. "Radiative Electron Capture into the K-, L-, and M-Shell of Decelerated, Hydrogenic <7e-Projectiles" Preprint GSI, Darmstadt, December 1991, GSI-91-67 (1991) 4. Stohlker Th., Kozhuharov C, Mokler P.H., Bernstein E.M., Warczak A., Stachura Z. "Radiative Electron Capture into Heavy Few Electron Projectiles: Cross Sections and Binding Energies" GSI Scientific Report, GSI, Darmstadt, March 1991, GSI-91-1 (1991) 173 5. Bichoński A.. Dutkiewicz E.M.. Knapp W., Macharski P., Mikulski J., Zagrodzki P., "Investigation of some metal levels in wheat samples", Raport IFJ, Kraków, November 1991. 6. Kopta S., Lekki J., Rajchel B. "Detection Ability and Elemental Contents Determi- nation by Elastic Scattering of Light Ions and by Recoiling Nuclei Measurements". Part.l. "Thick Targets Yields". Raport IFJ No 1574/AP, Kraków 1991. 165 7. Kormicki J., Breitenbach J., Carter H.K. "Development of the Unisor Separator Ion Source and the Ion Source for the Radioactive Beam Facility" Experimental Nucl. Struc- ture Physics Progress Report, Dept. of Physics and Astronomy Vanderbilt Univ., Nashville, Tennessee, July 1991. (1991) 108 8. Bechstedt U., Dolfus G., Ermer W., Hardt A., Krol G., Pawłat T., Rook M., Rosin D., Sagefka Th. "Preliminary Results of the Magnetic Measurements of COSY Dipol Magnets" IKP Annual Report 1990, Jul-24462, March 1991. (1991) Dissertations 1. Fornal B. "Charge Particle and 7-Ray Emission from Hot Nuclei 'at High Spins", Thesis, Institute of Nuclear Physics, Cracow (1991) Diploma Thesis !• Królas W. "Gigantyczny rezonans dipolowy zbudowany na stanach wzbudzonych jądra 5Bikfn, badany w reakcjach z utworzeniem jądra złożonego" ("Giant Dipole Resonance Built on Excited States of 65Mn Nucleus, Studied in Compound Nucleus Reactions") Praca mag- isterska IF UJ Kraków (1991) 2. Marczewska E. "Określanie struktury i składu pierwiastkowego kamieni nerkowych" ("Structure and Elemental Composition Detennination of Kidney Stones") Praca magisteroka IF UJ Kraków (1991) Lectures and Courses 1. Hrynkiewicz A.Z. "Metody fizyczne w medycynie i ochronie środowiska" ("Methodo of physics in medicine and in environment protection"), lectures given at Jagiellonian Univeraity, Department of Physics. GUESTS : Bernd ClefF (Germany) - 1.5 months Norbert Preikschas (Germany) - 6 months Albert Weber (France) - 20 days Nidal Yavuz (France) - 3 days VISITORS : Giacomo de Angelis (Italy) Hans Kluge (Germany) Francis Beck (France) Santo Lunardi (Italy) Dominique Curien (France) Hugo Maier (Germany) W. Górecki (Russia) Ewa Maydell (Great Britain) Hubert Grave (Germany) Charles Ring (France) Jurgen Heese (Germany) Klaus Schpur (Germany) Ja. L. Jachno (Russia) Michael Schramm (Germany) Peter Kleinheinz (Germany) Riidiger Schubert (Germany) 166 Internal Seminars l.M. Łach - "Struktura wysokospinowych stanów jadra g^Tbgij" ("Structure of high-spin 9 states in e5 Tb84 nucleus"), January 16. 2. D. Kulgawczuk - "Superpararriagnetyzm i rozcieńczenie magnetyczne badanie metoda spektroskopii moesbauerowskiej" ("Superparamagnetism and magnetic dilution studied by Mossbauer spectroscopy method"), January 23. 3. B. Rajchel, W.M. Kwiatek, W. Męczyński - "Pomiary koncentracji rtęci w organizmie człowieka" ("Measurements of mercury concentration in human body"), February 20. 4. B. Cleff (IKP, Miinster) - "X-ray polarization following heavy ion impact", March 20. 5. J. Heese (IIMI, Berlin)- "First results from the recoil detector prototype", April 10. 6. F. Maniawski - "Neutronowy magnetyczny czynnik kształtu. Pomiar i interpretacja" ("Neutron magnetic formfactor - Measurement and interpretation"), April 24. 7. A. Maj - "Gigantyczne rezonanse dipolowe, cz. I: Termiczne fluktuacje kształtów rozgrzanych jąder atomowych" ("Giant dipole resonances, part I: Thermal shape fluctuations in hot nuclei"), May 8. 8. M. Drwigga, B. Rajchel - "Zastosowanie metody IBAD na Separatorze Jonów do uzyskiwania warstw powierzchniowych o zadanych parametrach" ("Application of IBAD (Ion Beam Assisted Deposition) method to obtain surface layers of given parameters at ion sepa- rator"), May 15. 9. E. Marczewska - "Analiza składu chemicznego i pierwiastkowego mamieni nerkowych" ("Elemental and chemical composition analysis of kidney stones"), May 22. 10. W. Królas - "Gigantyczny rezonans dipolowy w S5Mń" ("Giant dipole resonance in ™Mn"), May 29. 11. K. Heller (UJ, Kraków) • "Współpraca systemów operacyjnych ULTRIX - VMS oraz ULTRIX - DOS'* ("Cooperation of operating systems ULTRIX-VMS and ULTRIX-DOS"), June 4. 12. E. Dutkiewicz - "Pomiary koncentracji par rtęci w gazach" ("Measurement of mercury vapours concentration in gases"), June 5. 13. P. Curien (CRN. Strasbourg) - "Wielolicznikowy system detekcji EUROGAM" ("Mul- tidetector system EUROGAM1'), June 13. 14. J. Komraus (US, Katowice) - "Transformacje związków żelaza w procesach przetwórczych węgla kamiennego" ("Transformations of iron compounds during manufacture processes of coal"), June 19. 15. W. Męczyński - "Przejście Gamowa-Tellera w rozpadzie beta 149Dy" ("Gamow-Teller transition in /3-decay of li9Dy"), June 26. 16. H. Ending (GSI, Darmstadt) - "Neutron measurements and giant resonance excitation in near relativistic heavy ion collisions", September 18. 17. R. Broda - "Nowe i stare izomery Sn produkowane w zderzeniach ciężkich jonów" ("New and old Sn isomers produced in heavy ion collisions"), October 9. 18. M. Cholewa - "MUcrowiezka i jej zastosowania" ("Microbeam and its applications"), October 16. 167 19. E. Maydell (University of Strathdydc) - "Emisja elektronów wywołana bombar- dowaniem ciężkimi jonami" ("El«ctron emission induced by heavy-ion bombardment"), Oc- tober 23. 20. A. Hrynkiewicz - "Informacja o działalności Komitetu Badań Naukowych" ("State Committee for Scientific Research - recent activity"), October 30. 21. R. Broda - "Nowe spojrzenie eksperymentatora na zderzenia ciężkich jonów" ("New experimental approach to heavy-ion collisions"), November 6. 22. J. Wrzesiński - "Próba kompletnej spektroskopii dla jąder 143iVrf" ("Attempt to com- plete spectroscopy of U3Nd nuclei"), November 13. 23. J. Czerniawski (UJ, Kraków) - "Jak zrozumieć szczególną teorie względności" ("Un- derstanding of the specific theory of relativity"), December 4. Invited Talks 1. R. Broda "Sn isomer8 produced in henvy ion collisions", International Masurian Lake School, Piaski, Poland, September 1991. 2. R. Broda "Zderzenia ciężkich jntiów badane mt'tuda koincydencji gamma-gamma" ("Heavy-Ion Collisions Investigated by 7 - 7 Coincidence Method") Środowiskowe Seminarium Fizyki Jadruwej, IF UJ, November 1991. 3. R. Broda "Mass, Charge and Angular Momentum Transfer in Heavy-Ion Collisions Studied by Gamma-Gamma Coincidences", Hahn-Meitner Institute, Berlin, January 1992. 4. J. Styczeń "High Spin States in 4R5e via Fussion-Evnporalion Reaction", INFN, Legnaro, May 1991. 168 ; 5 ; Department of Structural Research ( * W i DEPARTMENT OF STRUCTURAL RESEARCH 1 Activity Department no 3 of the Institute is named the Department of Structural Research, but its activity .spreads beyond the scope of the conventional meaning of this term. As a matter of fact, conventional structure determination is not and never has been at the center of its activity, although its work is based upon the most accurate information about structure available. The most adequate description would be: determination of motions in molecular crystals and in liquid crystals in relation to phases and phase transitions. In the field of liquid crystals the meaning of this label is the following: It has been proved that the generally accepted assumption of a rigid liquid crystal molecule as a whole performing translational (self-diffusion) and reorientational motions in, say , the nemalic nhase, cannot be valid. The current investigations try to determine the role of motions of various fragments of mesogenic molecules. As a matter of fact, it seems that these internal motions are the fastest on the time sca'e. They occur in the picosecond range, whereas the reorientations of the molecule occur in the 10~8 sec range (reorientation around the short axes). The role of research on the homologous series of liquid crystals should be emphasized, since molecular motions (both translatory and reorientational) participate in the generally known odd-even alternation phenomena, which means that the mobility ot the odd members of a series is smaller than the mobility of even ones. In the field of molecular crystals the phonon dynamics is being determined in the relation to phases, as has been said. Numerical calculations of the dynamics are per- formed basing on the atom-atom potential approach. In some cases (when the internal motion energy region overlaps the external one) a phenomenological treatment of a specified internal mode is needed in addition to that approach. Investigations are con- ducted whether and when such a treatment leads to incommensurate phases. A special emphasis is put on studies of molecular crystals which exhibit phase with reorientation- al disorder; some of these phases lead to a plastic behavior of the material. A thorough numerical approach is persuaded in connection with studies of the molecular structure and dynamics of crystal surfaces. The research described above is carried out by means of two high-level pieces of equipment: the adiabatic calorimeter — for specific heat measurements in the temper- ature range from ca 4 K to ca 400k and the infra-red Fourier spectrometer — providing spectra in the range from ca 15 cm"1 to ca 8000 cm"1. However the very important part of the research is based upon various kinds of neutron scattering measurements - in particular upon neutron diffraction (ND), inelastic neutron scattering (INS), and quasielastic neutron scattering (QNS). These measurements are carried out via var- ious programs of international cooperation. The laboratory has long and important 169 cooperation links willi the Institutt for energiteknikk at Kjeller, Norway. Obviously, in case WIKMI Lin; preliminary results call for further work, recourse is had to the applica- tion proceduro demanded by the most advanced neutron sources — the Laue-Langevin Institute in Grenoble or/and the Rutherford Appleton Laboratory in U.K. But the most important cooperation concerning neutrons is due to Poland's membership in the Joint Institute for Nuclear Research in Dubna, Russia. There, the activities of our laboratory can be extended through access to two advanced neutron spectrome- ters and participation in frontline studies of high temperature superconductors and of snperionic conductors. Finally, some more exotic aspects of our work should be mentioned which may determine its characteristics in the future. Firstly, a modern approach is taken to some problems of condensed matter in general and of the so-called soft matter in particular. This includes studies of chaos and of fractals; the fractal approach to liquid crystals should be emphasized in this connection. Secondly, ui pursue studies of possible penetrations of physics into other sciences, in particular into social science. This involves methods characteristic of synergetics. 2 Seminars Department no 3 initiated a specialized seminar under the general title: "Problems of molecular and macroscopic systems". It was held once a week and gathered 20 - 30 participants from this Institute and other institutes in Krakow. The topics oscillated between the field of motions in condensed matter and that connected with fractals, chaos and inter-disciplinary problems created by non-linear dynamical equations. Oc- casionally foreign guests were speakers. A special international seminar traditionally taking place in Kraków every second year and known as " Janik's Friends Meeting" was organized in our Institute in Septem- ber 1991. About 40 participants were present. The following lectures were given: 1. Molecular glasses (K.H.Michel, Belgium) 2. Structure and dynamics in liquid metals and alloys (U.Dahlborg, Sweden) 3. Computer simulations of incommensurate phases and textures (K.Parliński, Po- land) 4. Phason and amplitudon calculations in incommensurate phases of biphenyl (T.Wa- siutyński, Poland) 5. Incoherent inelastic neutron scattering from liquid water (J.C.Leicknam, France) 6. Dynamics of molecules in aligned nematic phases (M.Fontana, Italy) 7. Quantum chemical modelling of complex systems (J.L.Rivail, France) 8. Radiation damage and the safety of waste disposal in rocksalt (J.A.Goedkoop, The Netherlands) !)-. Humor in science as visualised by cartoonist (J. van Loev, The Netherlands) 170 If). The evaluation of research programs -•• an art rather than a skill (J. van Loev, The Netherlands) I I. Philosophical aspects derived from the physics of chaos (J.A.Janik, Poland) 12. Construction of kinetic energy from electron density and the consequence for density functional theory (A.dolas, Poland) 13. Structure and dynamics of surfaces and interfaces (P.Zieliński, Poland) 14. X-ray awl synchrotron expw'tmwita on surfaces ami interfaces (W.Press, Ger- many) 15. Time series (K.Otnes, Norway) 16. Paraniagnetism as a manifestation ofcompetition of possible magnetic structures (A.Czachor, Poland) 17. Molecule form and phase structure (D.Demus, Germany) 18. Modelling concepts of synergetics for dynamic processes in the society (VV.Weid- lirh, Germany) 19. Fluctuational models of self-organisation processes and some applications in bio- logy arid medicine (A. V.Clialyi, Ukraine) 20. Application of high pressures in condensed matter research (W.Nawrocik, Poland) 3 Foreign visitors in 1991 1. I)r F.Voliuci, OEN Grenoble, France 2. Prof. ,Jan van Loef, Intenmiversitair Reactor Institute, Delft, The Netherlands .'). l)r Kaare Otnes, Institute for energiteknikk, Kjeller, Norway I. Prof. Karl Michel, Department of Physics, Antwerpen University, Belgium fi. Prof. Werner Press, Institut ftir Experimentalphysik der Universitat Kiel, Ger- many 6. Prof. Jean-Louis Rivail, Universite de Nancy I, France 7. Prof. Marco Fontana, lnstituto di Fisica, Universita degli studi di Parma, Italy 8. Prof. Dietrich Demus, Martin Luther Universitat, Halle, Germany 9. Prof. Ulf Dahlborg, The Royal Institute of Technology, Institute of Reactor- physics, Sweden 10. Prof. Jean-Claude Leicknatn, Lahoratoire de Physique Theorique des Liquides, Universite Pierre et Marie Curie, Paris, France 11. Prof. Alexander V.Chalyi, Physical Department, Kiev Medical Institute, Ukraine 171 12. Dr L.Chernenko, Physical Department, Kiev Medical Institute, Ukraine 13. Prof. Jacob A.Goedkoop, Energy Centrum Nederland, Petten, The Netherlands 14. Prof W.Weidlich, Iiistitut fiir Theoretische Physik, Universitat Stuttgart, Ger- many 15. Dr A.V.Belushkin, Laboratory of Neutron Physics, JINP Dubna, Russia 16. Dr II.Kn-sse, Martin Luther Univcrsitat, Halle, Germany 17. Dr Ch.Wilson, Rutlierford Applclon Laboratory, England 18. Prof. A.Wurflinger, Universitat Hochuin, Germany 19. Dr. A.M.Yaremko, Univcristy of Kiev, Ukraine 4 Invited talks on international meetings 1. M.Bee, A.J.Dianotix, J.A.Janik, J.M.Janik, R.Podsiadly: A quasi-elastic neu- tron scattering study of the self-diffusion coefficients for the homologous series of 4,4'-di-ii-alkoxyazoxybcnze.nes, on European Conference on Liquid Crystals, Courmayeur, Italy, 10-15 March 1991. 2. J.A.Janik,J.M..Janik: Time scales of molecular motions in liquid crystals, Sum- mer European Liquid Crystal Conference, Vilnius, Lithuania, 19-25 August 1991. 3. J.A.Janik: Philosophical aspects derived from the physics of chaos, Janik's Friend Meeting, Kraków, Poland 23-27 September 1991. 4. T.Wasiutynski: Phason and ampliludon calculations in incommensurate phases of biphenyl, Janik's Friend Meeting, Kraków, Poland 23-27 September 1991. 5. P.Zieliriski: Structure and dynamics of surfaces and interfaces, Janik's Friend Meeting, Kraków, Poland 23-27 September 1991. 6. P.Zieliński: Surfaces and interfaces in oricntationally disordered crystals, XXI European Symposium on the Dynamical Properties of Solids, Autrans, France 29 September - 3 October 1991. 5 Publications 1. M.Massalska-Arodź, Phys.Rev. B43 (1991) 676 2. M.Massalska-Arodź, J.A.Janik Liquid Crystals 10 (1991) 135 3. J.A.Janik, J.M.Janik, A.Migdał-Mikuli, E.Mikuli, K.Otnes Physica B168 (1991) 45 4. J.A.Janik, J.M.Janik, T.Stanek, K.Otnes, J.of Mol.Liq.48 (1991) 111 172 •r). K.l'odsiadly, T.Stanek, .1. A.Janik, J.M.Jnnik, J.Krawrzyk, J.Mayer, Liquid Crys- tals 10 (IÜ91) 703 G. M.Bée, A.J.Dianoux, .I.A.Janik, J.M.Jauik, R.Poclsiadly, Liquid Crystals 10 (1991) 199, Report. IFJ No 1526/PS, Krakow 1991 7. .I.A.Janik, J.Mayer, S.Habrylo, l.Natk.mioc, W.Zając, J.M.Janik, T.Stanek, Re- port IFJ No 1529/PS, Kraków 1991, Phase Transitions 00 (1991) 8. J.Mayer, S.Urban, S.Habrylo, K.Holderna, I.Natkaniee, A.Wiirflinger, W,Zając, Phys.Stat.Sol. (b) 166 (1991) 381 9. J.Chruściel, W.Zając, Liquid Crystals 10 (1991) 419 10. l.Natkaniec, V.D.Khavryutchenko, E.F.Sheka, VI School on Neutron Physics - Alushta 1990 JINR Ü3, 14-91-154, Vol.11, (1991) 157 11. V.E.Antonov, I.T.Belash, A.I.Kolesnikov, J.Mayer, l.Natkaniec, E.G.Poiiyutovsky, V.K.Fedotov, FTT 33(1) (1991) 152 Sov. Solid State Physics 33 (1991) 12. A.I.Kolesnikov, l.Natkaniec, V.E.Antonov, I.T.Belash, V.K.Fedotov, J.Krawczyk, J.Mayer, E.G.Ponyatovsky, Physica B 174 (1991) 257 13. E.Sheka, V.Khavryutchenko, I.Natkaniec, V.Ogenko, I.Markichev, A.Muzychka, P.Nechitailov Physica B 174 (1991) 182 I'l E.Sheka, E.Nikitina, V.Khavryutchenko, V.Zayetz, I.Natkaniec, P.Nedntailov, A.Muzychka, Physica B 174 (1991) 187 IH. I.Natkantec, J.Fricke, V.Khavryutclienko, I.Markichev, A.Muzychka. V.Ogenko, G.Reichenauer, E.Sheka, Physica B 176 (1991) (in press) 16. A.V.Belushkin, C.J.Carlile, W.F.David, R.M.Ibberson, L.A.Slmvalov. W.Zajq«:, Physica B174 (1991) 268 17. P.Zieliński, Phase Transitions 30 (1991) 117 18. P.Zieliński, J.Phys: Condensed Matter 3 (1991) 2299 1!). J.Hubert Synergetic sociely( application of information-thermodynamic formalis- m in social science modelling and ita practical implications). Library of Dialogue, Warsaw University, 1991 173 6 Staff 1. Jerzy Brańkowski engineer 2. Jerzy Janik professor, head of department 3. Jerzy Hubert dr hab 4. Jan Krawczyk dr 5. Władysława Lisiecka sexretary 6. Jacek Mayer dr 7. Maria Massalska-Amdź dr 8. Ireneusz Natkaniec dr 9. Andrzej Ostrowicz engineer 10. Tadeusz Sarga technician 11. Janusz Sokolowski engineer 12. Jan Sciesiriski engineer 13. Tadeusz Wasiutytiski dr hab 14. Wacław Witko dr I.1). Jacek WójŁowicz pluł Ktudeiit 1(5. Wojciech Zając di 17. Tadeusz Zaleski dr dcctmiiician 1R. Piotr Zieliński dr 174 PHASON AND AMPLITUDON CALCULATIONS IN INCOMMENSURATE PHASE I OF BIPHENYL T.Wasiuty ński Institute of Nuclear Physics, ul.Radzikowskiego 152, 31-342 Kraków, Poland S"lid biphetiyl exhibits interesting sequence of the phase transitions: commensurate - incom- mensurate I incommensurate II extensively studied iti wide range of temperatures and pressures [I]. The lattice dynamics in all throe phases was studied by various techniques including neuUon scattering [2]. Tim prnsent, contribution is devoted to the lattice dynamics in the incommensurate }>hsiw I of biphenyl. H is the* natural continuation of our calculation of the lattice dynamics in the high temperature phase and tin* soft mode [3]. We follow the formulation of the lattice dy- uumitK iu incommensurate crystal phases givnn by Janssen [4] based upon the assumption that the atoms pi'iforin small vibrations around their now positions which are only slightly different from the romineiisurnli'. The force constants for the. modulated crystal are approximated by; *(",>/, T) = *0(ff, jj') + A«J»i(n, j/, r) whoir 'toliT, jj') is the contribution of the averaged structure and is phase independent. The per- turbation l rrllects the fact that the new phase is incommensurate. Our next assumption is that thf modulation is described by the single plane wave given by the critical wave vector. As the result evi-ry plnmoii mode is splitted into the doublet corresponding to symmetric, and antisymmetric cou- pling of phoiiiiiis which dilfcr by 2q. The phonon mode which is soft in the high temperature phase splits into pliasnii and amplitudon in the incommensurate phase. 7 =--(£,-40, .22) = (-.02,r/,.22) = (-.02, .40.C) 20 15 10 -0.02 0.06 0.32 040 0.48 0.14 0.22 0.30 i " < Figure 1; Pliason dispersion in Mirce main direction in reciprocal space References [1] Il.Cailleau, !na» niwnsnratc Phases in Dielectrics vol.2, page 71, North Holland 1986, and ref- fintiice* therein. [l\ P.Uunois, F.Moussa. M.H.Lamee-Cailleau and ;'ailleau, Phys.Rev. B4O(1989)5042. [3J T.Wasiutyński and Il.Cailleau accepted fur pubh.-nlwn in J.I'hyit.C: Solid State Physics [4] T.Jnnssftn, .J.Phys.C: Solid State Phys.l2( 1979)5:381 175 Influence of external stress on the structure of surfaces in /ID! diamond-like crystals P. Zielinski When a surface is cleaved out of an otherwise perfect crystal the interactions involving the discarded atomic planes parallel to the created surface are eliminated and the interactions between the remain- ing planes are modified in the vicinity of the surface compared with the interactions i' ie infinite crystal. This makes the reaction of the structure of the crystal to even a homogeneous external influence spatially inhomogeneous. Only far enough from the surface becomes the structure of such a crystal under a homogeneous stress peculiar to the infinite material. The method developed by the author on the basis of the surface and interface response theory [1] allows one to relate the expected structure of the surface with the strength of the effective force constants known, e.g., from the phonon dispersion curves [2,3]. It has been remarked by Cousins el o/[4j that the distance of the atomic planes perpendicular to the crystallographic direction (001) of the crystals C, Ga, and Si undergone the uniaxial homogeneous stress with the axis in the direction (110) perpendicular to the surface normal changed about 30 % stronger near to the surface than the corresponding distances in the bulk. In the present work [5] the shift of the (001) atomic planes in the diamond-like crystals C, Ge, Si and Sn has been predicted with the use of the force constants of McMurry et al [6] as a function of the orientation of the axis of the applied stress in. the plane (001). In all the crystals the distances of the atomic planes change with the depth into the crystal according to a damped oscillating curve. The difference of the variation of the interplanar separation near to the surface and in the bulk are shown in the Figure 1. for two possible types of the (001) surface of the diamond crystal as an example obtained results. 10'3 A 3 to A (*) 3.0 30 xli) I 2.0 2.0 1.0 1.0 IT/2 IT/4 IT/2 Flgurel.(a) Variations in the firstx'(l) (— • — Jandsccondjr'OX ) intcrlayer distances at the (001) surface of type 1 in diamond under a uniaxial stress of 1 GPa with its axis making an angle with the direction (100). The corresponding variations in the interlayer distances *''(/) (— —) and t '(I) ( ) in the bulk are also shown. References [1] L. Dobrzyński, Surf. Sci, Rep. 6, 119 (1986) [2] P. Zielinski, Phys. Rev. B38,12338 (1988) [3] P. Zielinski, J. Phys.: Condens. Matter 2, 857 (1990) [4] O. S. G. Cousins el al, J. Phys C: Solid State 20,29 (1987) [5] P. Zielinski, J. Phys.: CW..>is. Matter 3, 2299 (1991) [6] H. 1. McMurry et al, J. Phys. Cliem. Solids 28, 2359 (1967) 176 A quasielaslic neutron scattering study of the self-oiffusion coefficients for the homologous series of 4,4'-di-n-alkyloxyazoxybenzenes by M. BÉRt. A. J DIANOUXJ, J. A. JANlKtjV J. M. JANIKII and R PODSIADt.Y|| Hiiboratoirc dc Spectromćtrie Physique. Université Joseph Fourier, B.P. 87, 38402 Saint-Martin D'Hères CEDEX, France {Institut l.aue-Langevin, B.P. 156X, 38042 Grenoble CEDKX. France § Henryk Niewodniczański Institute of Nuclear Physics. ul. Radzikowskiego 152, 31-342 Kraków, Poland || Laboratory or Chemical Physics, Faculty of Chemistry of the Jagicllonian University, ul. Karasia 3, 30-060 Kraków, Poland (Received 14 December 1990; accepted 19 February 1991) Incoherent quasiclastic neutron scattering measurements performed with high resolution ( - I /ieV) have provided the diffusion coefficients for translation of four members of (be 4,4'dt-/j-alkyioxyazoxybenzene scries in thetr nematic phases. An cxld even etTcct in these coefficients was observed. The results were compared wilh those previously obtained by Noack via ltw NMR technique. There is fairly good aureemenl between his NMR and our QNS results. Intense quasielastic neutron scattering of 4,4'-diethyoxyazoxybenzene and its connection with the inelastic neutron scattering spectrum by R. PQDSIADLYf.T. STANEKt. J. A. JANIK*J, J. M. JANIKt. J. KRAWCZYK§ and J. MAYER§ t Laboratory of Chemical Physics, Faculty of Chemistry of the Jagiellonian University, Kraków, Poland X 'Henryk Niewodniczański' Institute of Nuclear Physics, Kraków, Poland §Joint Institute for Nuclear Research, Dubna, U.S.S.R. (Received 6 November 1990. accepted 3 May 1991) This is a continuation of a previous study of the odd-even effect for compounds of the series of ^'-di-n-alkyloxyazoxybcnzcncs. The reduction of the elastic component of the neutron scattering spectra {the elasticity depression), studied earlier at constant AT from the clearing point, has now been studied at constant temperature. The cthyoxy member of the series shows an exceptionally large elasticity depression; this is interpreted as evidence of a small stcric hindrance for molecular motions due to the high neniiiiic order parameter. This statcmeni has been corroborated by the inelastic neutron scattering measurements for solid compounds of the series 177 ol[ PHASE DIAGRAM OF 4,4 -di-n-Bl ITYLOXY A ZOXY BENZENE Neutron Diffraction Measurements at Higher Pressures J. A JANIK Henryk Niewadnwzański Institute of Nuclear Phvsics, ul. Radzilcowskieya I5P, 31-342 Kraków, Polami i MAYER1. S HABRYŁO2, I NATKANIEC1, W. ZAJĄC' Laboratory of Neutron Physics of the Joint Institute for Nuclear Research, 141980 Dubna. USSR J. M. JANIK and T STA NEK Faculty of Chemistry of the Jagiellonian University, Karasia 3, 30-060 Kraków, Poland i Rewii ej 14 January I9QI. in final Imm IS May 1991) By using neutron diffraction for the identification of phases, the temperature-pressure diagram was determined for solid 4,4'di-n-buty|oxyazoxybenzene (4-OAOB). in the temperature range from room temperature to ca t 115 C and the pressure range from atmospheric pressure to ca. 2 kbar. The possibility of a critical point terminating the coexistence curve of phases I and II is suggested Undercooling phenomena, and spontaneous transitions from meiastahte in stable phases are observed and discussed KF.Y WORDS din-buiyUixy;i7iixynen?.cne. neutron difliaeliun, phase transitions, pressure studies ODD-EVEN AL TERNAHONOF FREEDOM OF ALKYL CHAIN MOLECULAR MOTIONS IN NEMATIC AND ISOTROPIC LIQUIDS AS OBSERVED BY 1HE NEUTRON INCOHERENT SCATTERING I A. JANIK H Nleuodnlcz^n«kl Institute of Nuclear I'hyslcs, Jl-31? Krakow (Poland) J M .JANIK ami I SIANEK, Faculty of Chemistry ol the Jaglel Ionian University. :t0-060 Kraków (Poland) K OTNKS. Institute of Energy Technology. 2007 K)ellei (Norway) (Received IS ilrtober 1^89) SUMMARY Quasielasl ii: and elastic neutron incoherent scattering patleins were obtained for nrnatlc and isotioplc liquid phases of substances belonging to the PAA homologous series (n-1-5). Tim spe<.tia were explained as arising f i otn Intramolecular reni lental ions of and in the alknxy lalls The conclutiun time region of those mulions is several p'.- The intensity of \hn elast ic i omponcnt of the spprlia exhibits the odd-even effert It is explained as ror related to fhler S uhi'h shout also an mid-even allct nation. and causes ;m iilteinatlnn of stfrir hindrance lo rnoleculnt motion:; the result"; f 178 Neutron quasielastic scattering results for Me(NH3)6(XY4)2, '' Me(NH3)6(XY3)2 and Me(NH3)6X2 compounds, compared with the calorimetric and Raman line width data - a new analysis J.M. Janik", J.A. Janikb, A. Migdai-Mikuli3, E. Mikuli" and K. Otnesc 'Cltcmkiil Faculty of the Jagieltonian University. 30-060 Kraków, Polami *H. Niewodniciariski Insiiute of Nuclear Physics, 31 -3J2 Kraków. Poland 'liisiiiuit far energiieknikk, 2007 Kjeller, Norway Received 5 Maich I WO Revised manuscript received 1 May 1990 Ouasieliisiit neutron scattering data for NUNHj^CIO,)., MgfNH.UCIO,).. NilNH.^BF,),. Ni(NHt)„(NO,),. M.BlNH.UMO,),, Ni(NH,)„CI,-nnd Ni(NH,)(Br, were subjected to a new analysis in which not only the correlation times lor NH, iimaxia) reoricntations but also a new parameter "excess elasticity' were determined. The new parameter gave us iiiiotmillion concerning .inharmonic Iterations of the NH, groups. All neutron dam were compared with the calorimetry and Raman line width data. An attempt to ascribe the phase transformations to transitions from hindered to free icoiieniiUiS of the NH, groups or/and the an ions was made. SPECIFIC HEAT RELAXATION IN GLYCEROL ) o'l M.Massalska - Arodż Institute of Nuclca. Physics, ul.Radzikowskiego 152, 31-342 Kraków, Poland The frequency dependence of specific heat observed by Birge and Nagel in supercooled glycerol was found to be obeying the fractional power - lows in high and low frequency limits. The relaxation of specific heat has been interpreted in terms of the Dissado - Hill many - body theory. The evaluated values of the exponents suggest a relatively high degree of local correlations {in = 0.73) and a low degree >f long - range correlations (m = 0.73) of motions responsible of the relaxation observed. Agreement of the n and m parameters with those calculated from the dielectric and acoustic relaxation data was found. A possibility of introducing the fractal concepts into the (Inscription .if relaxation phenomena in glycerol was pointed out.. Department of Theoretical • \ Physics r I "' ift 1. FOREWORD The research done at the Department of Theoretical Physics of the H. Niewod- niczański Institute of Nuclear Physics concerns various theoretical problems of low, medium and high energy nuclear physics, elementary particle physics, astrophysics, general physics and mathematical physics. Both formal problems as well as the more phenomenologically oriented ones are being considered. Phenomenological research is closely linked with exper- imental program in elementary particle and nuclear physics in various laboratories in the world. This includes elaboration of predictions for experiments which will be performed at HERA, SSC and LHC colliders. Department of Theoretical Physics actively collaborates with other Departments of our Institute as well as with other institutes in Poland and abroad. The research program is now formally divided into three main topics: (1) - the role of the Galilean relativity principle in quantum mechanics, (2) - dense and/or hot hadronic matter, (3) - structure of hadrons studied in particle and nuclear interactions. These are three approved proposals by the Scientific Research Committee within the new system of the scientific research finance policy in Poland. The details of the results obtained in various fields are summarised in the abstracts presented below. Besides pure research our Department is actively engaged in the graduate and un- dergraduate teaching program. During 1991 one PhD and one Msc theses have been completed. At present we have three PhD students who should finish their theses during the forthcoming year. Also the lectures for graduate students at the Institute are read by the members of the Department. Head of Theory Department prof.Mr hab. Jan Kwieciński 181 2. STAFF Permanent staff Piotr B0CHNACK1 Wojciech BRONWWSKl Marcin GERKASK1 Piotr CZERSKI Wiesław CZYŻ* Wojciech FLORKOWSKI Kr/ysztof GOLEC-BIERNAT Andrzej HORZELA Robert KA MIŃSKI Edward KAPUŚCIK Marek KUTSCHERA Jan KWIEC1ŃSK1 Uvm\ <>f |).-|im Leonard LEŚNI AK Andrzej MALECKI Ewa PAGACZEWSKA S<-net,,,iy Marek Stanisław Piotr ŻENCZYKOWSKI * also at the Institute of Physics, Jugellonian University, Chairman of the Scientific Council of the Institute of Physics, Jagellonian University, Chairman of the Scientific Council of Nicolas Copernicus Astronomical Center 182 3. ABSTRACTS Collective Modes in a Slab of Interacting Nuclear Matter W.M. ALBERICO \ P. CZERSKI, V.R. MANFREDI2, A. MOLJNARI1 Dipartimcnto di Fisica Teorica, Univursita di Torino, Italy 2 Uiparlimtnto di Fisica, Universita cli Padova, Italy We study the properties of a. slab of nuclear matter. The behaviour with the slab thickness of the particle density, kinetic energy density and surface tension are given in the non-interacting case, together with the slab free response to an external field. Next we introduce a zero-range isovector interaction among the nucleons and analyse the slab collective excitation. For moderate momenta hard and soft modes are found, which exhaust most of the excitation strength. Their position and splitting energy favourably compares with the splitted giant dipole resonance experimentally seen in deformed nuclei [1]. Quantum Tunnelling in the Periodically Driven SU(2) Model R. ARVIEU2, P. KAMJŃSKI1, M. PLOSZAJCZAK1 1 INP Ciacow and GANIL, France n tnstitul des Sciences Nucleilires, 33 Avenue des Maityrs, F-38026 Grenoble Cedex, France The tunnelling rate is investigated in the quantum and classical limits using an exactly soluble, periodically driven SU(2) model [2]. The tunnelling rate is obtained by solving the time-dependent Sclirodinger equation and projecting the exact wave-function on the space of coherent states using the Husimi distribution. The oscillatory and coherent tunnelling of the wave-function between two Hartree-Fock minima is observed. The driving plays an important role increasing the tunnelling rate by orders of magnitude as compared to the semiclassical results. This is due to the dominant role of excited states in the driven quantum tunnelling. 183 Phase Space Structure of Simple Nuclear Models Ąh° R. ARVIEU l, P. ROZMEJ 2, M. PIOSZAJCZAK 3 IliBtitilt des Sciences Nucleaircs, 53 Avenue des Martyrs, F-38(120 Grenoble Cedex n Department of Theoretical Physics, Institute of Physics, Mnria Curle-Sklodnwska University, 2U-0S1 Lublin, Poland 3 INP Cracow and GANIL, France We present a schematic description of the eight dimensional phase space of a uucleon in a deformed harmonic oscillator with a simple spin orbit term [3]. Ordered trajectories have been identified as well as chaotic ones with dimensions D = 4,5. Prolate and oblate shapes are considered. Moreover we discuss in details the phase space features of the SU(2) and SU(3) Lipkin model using the Husiini distributions to exhibit the classical properties in the quantum solutions of the Lipkin model. Properties of Husimi distributions with the number of particles are exhibited and new scaling properties are found in the regular regime. , Shadowing in Inelastic Lepton - Deuteron Scattering B. BADEŁEK >, J. KWIECIŃSK1 Institute of Experimental Physics, Warsaw University Warsaw, Poland Shadowing in inelastic lepton-deuterori scattering was analysed using the double in- teraction formalism where shadowing was related to inclusive diffractive processes. Both the vector meson and parton contributions were considered for low and high Q2 values including QCD corrections with parton recombination for high Q2. These Ql values were chosen to correspond to existing experimental data and to the possible HERA measure- ments. Detailed discussion of various shadowing mechanisms is given. As expected the shadowing effects were found to be very small, less than 2% or so, in agreement with the recent precise measurements performed by the New Muon Collaboration [5]. 184 Parton Distributions and Deep Inelastic Processes at Smali x B. BADELEK l, K. CHARCHULA '-a. K. G0LEC-B1BRNAT, M. KRAWCZYK3, J. KWIECIŃSK1, A.D. MARTIN\ D. STRÓZIK-KOTLORZ, P.J. SVTTON* Institute of Experimental Physics, Warsaw University, Warsaw, Poland 2 Deutsches Eloktronen-Synchrotron DESY, Hamburg, Germany Institute of Theoretical Physics, Warsaw University, Warsaw, Poland Department of Physics, University of Durham, Durham, United Kingdom The measurements at the ISR, CER.N and Tevatron colliders were use I to determine the values of the central eikonal and hence to estimate the energy dependence of the semi- hard component of the cross-section for proton - antiproton scattering. It was compared with QCD expectations obtained from gluon distributions which incorporate both singular small x behaviour and shadowing corrections. The expectations for the asymptotic form of the total pp cross section were discussed with the emphasis given to the effects of gluon saturation [32]. The very small .T behaviour of the gluon distribution in a proton was analysed by solv- ing the Lipatov equation without [42] and with shadowing effects [31,33]. The emergence of an x~x ochaviour and the eventual taming of this behaviour by shadowing term was found. This dynamically-generated gluon distribution was compared with (i) the results of u recent next-to-lead ing order QCD structure function analysis which incorporated both n singular x~1^2 behaviour and shadowing corrections, and (ii) the double logarithm ap- proximation. The semiclassical approximation of the Lipatov equation was formulated in order to compare with earlier analyses based on this approximation. In [4] the physics of of deep inelastic processes in the region of small x was reviewed. The. theoretical concepts concerning the Regce limit of deep inelastic scattering were sum- marized and the recent theoretical results on the small x limit of parton distributions in perturlmtive QCD were discussed. Presently available experimental data on the free and bound nudeon structure functions at small x were reviewed in detail and their theoretical interpretations (including low x, low Q7 region) were discussed. QCD predictions for the 5 2 deep inelastic scattering structure functions F2 and Fti in the small x (10~ < x < 10~ ) find moderately large Q7 region relevant for HERA (Q2 ~ 10 GeV2) were given. 185 Coiwective Stability of Hot Matter in Ultrarelativistic Heavy-Ion Collisions '/J G. BAYM1, W. FLORKOWSKI2'3, B. L FRIMAN^, P. V. RU U SKAN EN* Department of Physics, University of Illinois at Urhana-Champiiign, USA 2 INP Crncow, Poland 3 Gesellnthaft für Scliwenonenforscliiing, Darmstadt, Germany IiiHtitut für Kernphysik, Technisch« Hochschule Uarmstatlt, Germany Department, of Physics, University of Jyväskylä, Pinland The convective stability of strongly interacting matter undergoing hydrodynamic flow in ultrarelativistic heavy-ion collisions is studied in both the quark-gluon plasma and hadron gas phases. We find that this stability depends on the form of the initial conditions assumed for the hydrodynamic flow. In the case of the initial conditions corresponding to partieJ transparency the flow of the quark-gluon plasma is stable whereas the flow of the hadron gas is convectively unstable. The timescale for hydrodynamic oscillations around the (stable or unstable) equilibrium state is found to be larger than the expected lifetime of the system, suggesting that the flow in either case is very close to neutral convective equilibrium. i Galilean Covariance in Classical and Quantum Mechanics P. BOCHNACKI, A. HORZELA, E. KAPUŚCIK1, J. KEMPCZYŃSKI2 1 J1NR Dublin and INP Cracow, Poland 2 INP Cracow, Poland We formulated a Galilean covariant approach to classical mechanics. In tliis scheme constitutive relations defining forces are rejected as breaking the covariance principle. The acting forces are determined in fully covariant way from some sets of fundamental dif- ferential equations which may be defined for any particular problem. The analysis of the covariance principle and transformation laws shows that the total energy of interacting par- ticle has to transform under Galilean transformations differently from the kinetic energy. The suitable transformation laws are found exactly for harmonic and damped oscillators and for anharnionic oscillator in the framework of perturbation theory [21]. The covariant introduction of forces plays also a crucial role in Galilean covariant formulation of quantum 186 mechanics. We solve this problem treating quantum foices as independently quantized ob- servables and constructing wave functions as functions depending on more variables than it is assumed in the standard approach [22,24]. Detailed analysis of the meaning of nonrelativistic transformation laws for the mo- mentum and the kinetic energy leaded us to the formulation of the concept of Galilean mass, in general different from the inertial mass [23,30]. This idea applied to many body systems in the scheme exhibiting the Galilean covariance of the formalism gives the possi- bility of their alternative description in which particles forming the system have individual kinematics but are deprived from individual dynamics. Dynamics exists only for a system as a whole and we consider this fact to be a classical prototype of tta "confinement" be- ing the phenomenon of non-dynamical origin independent from any particular modei of interaction [6,27]. Intermittency and Clustering in the One-Dimensional Lattice Gas Model P. BOŻEK1, Z. BURDA 2, J. JURKIEWICZ2, M. PŁOSZĄJCZAK1 1 INP Cracow and GANIL, Prance n Jagellonian Unversity, Cracow, Poland The generating functions of the scaled factorial moments of the distribution of the particles and links in the one-dimensional statistical model for variable bin size have been constructed [7]. The results show an intermittent like behaviour, in spite of the fact that the model does not exhibit any scaling behaviour and has a very small correlation range. The intermittency signal for the particles and links.was compared and the possible influence of the clustering in the cold hadronization on the size of the fluctuations was disscussed. Finite-Size Effect in the Intermittency Analysis of the Fragment Size Correlations P. BOŻEK \M.PLOSZAJCZAK \ A.TUCHOLSKI2 U 1 INP Cracow and GANIL, France Institute of Nuclear Studies, Świerk, Poland The influence of the finite size effect on the fragment correlations in the nuclear mul- tifragrnentation was studied using the method of the scaled factorial moments. The cor- relations in the fragments were calculated analytically for the one-dimensional percolation 187 model and for a statistical model of the fragmentation process [8], which for a certain value of a tuning parameter yields the power-law behaviour of the fragment size distribution. It was shown that the statistical models of this type contain only repulsive correlations due to the conservation lav/8. The comparison of the results with the those obtained in the non-critical one-dimensional percolation and with the numerical results obtained for the three-dimensional percolation at around the critical point was made. In the two latter modela there are some attractive correlations which were also seen in the experimental results on the nuclear miilUfragmentation. The analytical solutions allow to identify the origin of the repulsive correlations (the mass conservation) and of the attractive ones (the perimeter links). Intormitttency in Ultrarelativistic Nuclear Collisions P. BOŻEK x, M. PLOSZAJCZAK1 INP Cracow and GAN1L, France The effect of noastatistical fluctuations in ultrarelativistic collisions has been anal- ysed. Arguments are given to show that it is a nonlinear effect going beyond the simple nucleon-nucleon superposition models. This effect may have strong implications on our understanding of the collision dynamics. To describe the effect the model of the spatio- temporal intermittency in the interaction region was developed [9]. This model can explain the impact parameter and the projectile and/or target mass dependence of the strength of the fluctuations. The behaviour of the self-siinilar structures during the hydrodynamical evolution has been studied as well as the possibility of the detection of the spatio-temporal intermittency in the Bose-Einstein correlations, The implications of correlated emission on the Bose-Einstein measurements have been analysed. Finite-Size Scaling, Finite-Size Effects and the Dimensional Projection P. BOŻEK1, M. PIOSZAJCZAK1 ' INP Cracow and GANIL, Franco The implications of the scale-invariant multiparticle distributions have been studied. This description was compared with the predictions of «-model. The two approaches were shown to be largely equivalent [10]. This includes the case of the weak and strong intermitteiicy and similar behaviour for the scaled factorial moments as well as the scaled 188 factorial correlators. It was also shown that the dimensional projection does not alter this similarity and, moreover, it explains an experimentally observed difference between the slopes of the factorial moments and tin* factorial correlators. A quantitative method to analyse the projected one-dimensional data on the scaled factorial moments was proposed. The dimensional projection is known to destroy the intermittent behaviour. Till now there was no clear method to deal with this effect other than to go to the full dimensional analysis. We have proposed the finite-size scaling analysis of the scaled factorial moment data [11]. This analysis allows to extract the scaling indices of the underlying higher-dimensional scale-invariant distributions. Moreover, it exhibits the change of the effective transverse size involved in the dimensional projection with transverse momentum cuts applied to the data. It is the only way of deconvolution of the dimensional projection if the intermittency phenomenon'takes place in a space inaccessible experimentally in its "full-dimensional form", as the rapidity impact-parameter space. The detailed implications of the presence of a finite size in the system have also been adressed. In fact, the presence of such a finite-size changes already the full-dimensional cor- relations. This effect was studied on the example of the critical system in two-dimensions [12]. Two systems have been studied: one system consisted of an infinite plane and the second of an infinitely long strip with the finite width. The correlations in the two systems were related by the conforaial symmetry. The second system behaves in the projected one- dimensional analysis as an effectively one-dimensional system on distances of the order of the induced correlation range. Possible implications of this effect on the observation of the intermittency signal were disscussed. Electromagnetic Polarizabilities of the Nucleou W. BRONIOWSKl Recently electromagnetic polarizabilities of the nucleon have been remeosured. We have analyzed these polarizabilities in chiral soliton models of '.he nucleon, with emphasis on the splitting between the neutron and proton polarizabiliti. 3. One can show, using general arguments, that the neutron should have a bigger electric polarizability than the proton. This is directly related to the charge density profile. Oir model calculation confirms these predictions. The calculations arc done using smnidassical linear response theory in a system of mesons and quarks [13]. 189 Quarks with a Pion Condensate as a New Phase of Matter P W. BR0NI0WSK1, A. KOTLORZ, M. KUTSCIIERA It is argued that the chirally broken quark matter is the ground state of baryon matter at densities of the order of a few nuclear densities. Properties of this new phase of matter are studied in the framework of the sigma model with quark and meson degrees of freedom. Existence of this phase is a general feature of models based on chiral dynamics, such as the sigma model. Phenomenological consequences on the physics of dense matter are discussed, in particular we describe interesting magnetic properties of the phase [14,34]. Final State Interaction of Nucleons in Knock-Out Reactions F. CANNATA \ J.-P. DEDONDER 2, L, LEŚNJAK Dipartiniento di Fisica ami INFN Bologna, Holy n Division de Physique Theorique, Institut dn Physique Nucleaire. Orsay and Laborntoirc de Physique Niicleaire, University Paris 7, Paris, Franco Electromagnetic knock-out of nucleons from nuclei is a valuable source of information on the nucleon propagation in nuclear matter. The transition form factor for a nucleon going from an initial bound state to a final scattering state is calculated. We discuss an efficient, method leading to an evaluation of the final state interaction effects at high energies of outgoing nucleons. This method is based on the fact that a convergence of the partial wave expansion series for the difference between the exact form factor and the plane wave approximation to it is faster than a convergence of the standard partial wave expansion series [15]. Two and Three-Channel Models of the /o(975) Meson F. CANNATA \ J.-P. DEDONDER 2, L. LEŚNIAK Dipartiniento di Fisica and INFN Bologna, Italy 2 Division de Physique Theorique, Institut dc Physique Nucleaire, Orsay and Laboratoire de Physique Nucleaire, Universite Paris 7, Paris, France A separable potential formalism is used to study KK threshold effects. In addition to the 7T7T and KK channels, a third channel with heavy constituents is introduced to simulate 190 the role of additional channels in building up the /o(975) meson, assuming, in general, no direct interaction in the A A" channel. As a consequence, the coupling between the exotic channel and the A'A" channel is rather large. One can reduce further the three-channel problem to an effective two-channel problem where the /o(975) meson behaves as if it were a A'A" molecule bound by the coupling to the exotic channel. This is also supported by the fact that a single pole only, in the complex A'A' momentum plane, is associated to the /o(975) meson. Various physical observables, like the decoy branching ratio and the KK scattering length, are then disctissed in this effective two-channel framework [16,17]. Symmetry Transformations of Nonstandard Irreducible Characters of Groups Sp(2N), S0(2N -f 1) and their Application, M. CERKASKI Using some symmetries of the irreducible character functions of groups G(k) = SP(2N) S0(2N), S0(2N + 1) we establish a new and very simple algorithm for the transforma- tion of the nonstandard characters of these groups. This strongly simplified a calculation of branching rules for the group reductions U(k) \ G{k) frequently used in theoretical physics. This method has been tester! in a number of numerical calculations. Nuclear Collective Motion within the 0(N - 1) Invariant Dynamics ^ M. CERKASKI IN. MIKHAILOV1 Lnliorittnry for Theoretical Physics, .11NR, Dubna Assuming 0(N - 1) symmetry for an interaction term in the N-body Hamiltonian we find closed subsystem equations of motion. Forming the model in a geometrical way we show that nucleons move along the trajectories determined by the time dependent har- monic potential being a function of the collective variables. A class of stationary solutions which generalize the families of the S-Riemann ellipsoids leads to the cranking model with selfconsistency relations generated by the 0(n - 1) scalar part of the potential. We pursue this investigation studying a problem of general classification of stationary solutions for this model and preparing the computer program calculating selfeonsistent nuclear collective bauds. 191 Production of Hard Photons in Electron-Positron Annihilation into Hndrons \ W. CZYŻ1, A. DYREK2 also at Institute* of Physics, Jagvllouinn University Ri-ymontn i, 30-059 Kraków, Polnnil 2 Institute of Physics, Jagelloniau University Reymonta i, 30-059 Kraków, Poland Frequency of emission of prompt., hard photons radiated by the fast-moving quarks (antiquaries) in e~e+ annihilation into hadrons is estimated for the string model. The differential probability of emission of such photons is obtained from a sum rule which takes for the initial slaty of the emitter a classical trajectory. It is found that the string models are quite effective in production of hard photons (i.e., photons whose energies are substantial fractions of energies of the initial e+e~ pair) associated with production of hadrons. For 100 GeV e + e" initial energy the frequency of emission, u, of 10 GeV < fiu? < 40 GeV photons is estimated to be 10"4 Splitting of the Different Parity States <\iC? and Quantum Tunnelling in the SU(2) Model S. DROŻDŻ \ P. KAMIŃSK11-2, M. PŁOSZAJCZAK l-3 1 INI* Cracow 2 GANIŁ, France The splitting of different parity states in various models with the SU(2) symmetry has been calculated using different approximate schemes and then compared to the exact results. In case of the strong coupling betweeti shells, i.e. for large potential barriers in the semiclassical limit, the time dependent Hartrce-Fock approximation (TDHF) in the imagi- nary time yields very good results. Simultanously, the nonadiabatic effects are important. The overlap of the single-particle Hartree-Fock (SPHF) excited state and the TDHF state can be a measure of the adiabaticity. One. cannot use the cranking approximation when this overlap is large and comparable with the overlap of the SPHF for the ground state and I Supported in part by the Polish Ministry of Education, Grant DNS-P-04/215/90-2 nnd DN No 2-00054 91-01. 192 the TDHF state. This situation happens for all SU(2) models containing the p1 terms in the classical limit. For these models,one observes a remarkable difference in the behaviour of the energy splitting of parity dublets as a function of the strength of the two-body inter- action for even and odd number of particles. The TDHF approximation always reproduces the results for the even number of particles. The seniiclassical calculation of splitting for the odd number of particles requires an introduction of the additional term to the semi- classical action. This effect seems to be closely related to the Berry's phase and related anomalies. Properties of G Moments W. FLORKOWSKI We investigated the general features of the Gq moments in the case where they are applied in the analysis of the fluctuations of the rapidity distributions. In particular their dependence on the statistical background was clarified. Shadowing at HERA K. GOLEC-BIERNAT We study the possibility to see shadowing effects in the electron-proton collisions at HERA. The data which are not available yet are generated from the KMRS parton distributions and the Altarelli-Parisi equations with nonlinear shadowing terms of the "hot-spots" type. A global fit to the data is performed with the help of conventional input parton distributions and linear AHarelli-Parisi equations. Preliminary results show that the shadowing effects in the data can be explained in the conventional way provided the experimental errors are not smaller than 10%. 193 Relativistic Effects in Decay Channels of Scalar Mesons U, KA MIŃSKI L. LEŚNIAK, J.-P. MAILLET* Division do Physique Tlieorique, lnstitut dc Physique Nuclńaire, Orsay, Franrt* A separable potential formalism is formulated and used to describe the properties of scalar, isospin zero mesons including /o(975) and /o(14OO). Relativistic propagators in both TTK and KK channels are used. Rank two separable potentials are chosen in the nn channel and u rank one potential in the A" A" channel. Parameters of the potentials will be fixed by comparison with experimental data. Preliminary results indicate a large influence of the relativistio effects on values of the TTJT interaction strengths and range parameters. Important relrttivistic effects are also found in the A'A" channel if the KK interaction form factor has a short range character. They grow with increasing KI\ effective mass. Quantum Tunnelling in the SU(2) Model with Quasi-Periodic and Random Driving P. KAM1ŃSK11, M. PŁOSZAJCZAK* 1 INP Cracow »»d GANIL, France Quantum evolution of the wave-packets in the time-dependent SU(2) (TDSU(2)) spin system is investigated for different kinds of driving in the quantum and classical limits. The tunnelling between the two degenerate Hartree-Fock minima is studied by solving the. Schrodinger equation and using the Husirni distribution formalism. The considerable enhancement of the tunnelling rate due to the driving is observed. Depending on the type of driving , the evolution can be either periodic and coherent (the time-periodic driving) or irregular (the random series of pulses). The relation between the structure of the classical phase-space and the character of quantum tunnelling was found. If the classical trajectories are regular then one observes the periodic and coherent tunnelling of the initial wave-packet between minima of the classical potential. Its rate is large due to the presence of the irregular structures in the classical phase-space at higher energies. On the contrary, when the classical trajectories are chaotic at all energies, the wave tunnelling is irregular. The initial wave-packet easily goes through the barrier, but then it rapidly spreads over all the available phase-space and does not return to the stnte close to the initial condition. For (lie random driving force, the diffusive character of the energy growth in time, was 194 found. In the limit of a small particle! number, the time-scale of the evolution is much shorter. In this case the simple four-level model explains qualitatively the mechanism of the driven fast tunnelling. Properties of Classical Electrodynamics III E. KAPUŚCIK 1 JINR Dublin and INP Cracow, Poland A non-standard formulation of classical electrodynamics is proposed. In this scheme the electromagnetic, fields D and H as well as polarization P and magnetization M vectors must be distributions while the electromagnetic fields E and D are test functions. The mathematically precise description of all these quantities gives the possibility of avoid- ing the troubles of the conventional electrodynamics connected to the problem of the distribution-valued sources, like for example the point charge [25]. Unknown Aspects of Relativity E. KAPUŚCIK ', /. KEMPCZYŃSKI'2, A. HORZELA A ^ 1 JINR, Dut.na and INI1 Cracow, Poland 2 INP Cracow, Poland We have continued our research generalizing ideas of conventional relativity theory* In [28] we have proposed a generalization of the Einstein equivalence principle valid not only for gravitation but for all fundamental interactions. The principle is based on the concept of full symmetry between space-time and boundary conditions dependence of the fields which opens more freedom for the transformation of the physical quantities. Applying the idea of treating transformation laws as one of the most important fundamentals of any physical theory we have considered the possibility to define a new class of mathematical objects and to introduce them into the general relativity. These objects have not geometrical meaning, generalize the concept of the affine connection and enables us to replace the metric tensor and the affine connection by the unified mathematical structure [26]. We have reanalized the Einstein radiolocation method and have described the synchronization procedure in the case when light moving nonuniformly is used for the clock synchronization. It has 195 be«n shown that a relativity theory with both an invariant acceleration and an invariant velocity of light is possible [20,29]. Polarized Phases of Dense Matter and Magnetic Fields of Neutron Stars M. KUTSCHERA, W. WÓJCIK l Institute of Physics, Technical University, Cracow Possible mechanisms of a spontaneous spin polarization in the dense baryon matter of the neutron star core are discussed. It is shown that protons in the core of the neutron star are likely to be polarized. The quark core if present can be also magnetized due to ordering of quarks spins in the pion-condensed phase of a chirally broken quark matter. This model accounts for a recent evidence that decay of magnetic field occurs only for neutron stars which accreted matter in their evolution [35,36]. Nuclear and Partonic Dynamics in High Energy Elastic Nucleus-Nucleus Scattering A. MALECKI A hybrid description of diffraction which combines a geometrical modelling of multiple acnttering with many-channel effects resulting from intrinsic dynamics on the nuclear and subnudenr level is presented. The application to 4He - 4Ht? elastic scattering is satisfac- lory. Our analysis suggests thnt, at large momentum transfers, the parton constituents of niH'lcons immersed in nuclei are decoufined [39]. • Vl> Inelastic Diffraction and Equivalence of States A. MALECKI A new approach to diffraction, based on the concept of equivalent states, is applied to the inclusive inelastic scattering. Differences from the classical description of Good and Wnlkrr air pointed out [38]. 196 Inlermittency in Nuclear Multifragmentation M.PŁOSZAJCZAK ', A.TUCHOLSKIa ^ *(- !NP Cracow nml OANIL, Krańce Institute of Nuclear Studies, Świerk, Poland and GSI Darmstadt, FRG The fluctuations of the fragment size distribution in a percolation model and in nuclear multifragmentation following the breakup of high-energy nuclei in the nuclear emulsion have been studied using the method of scaled factorial moments [40]. An intermittent pattern of fluctuations has been found in the data as well as in the percolation lattice calculations. This feature is a consequence of both a self-similarity in the fragment size distribution and a random character for the scaling law. These fluctuations are, in general, well described by a percolation model. The multifractal dimensions are calculated and their relevance to the study of possible critical behaviour has been pointed out. On the Nuclear Incompressibility Modulus ' ^ St. ZUBIK Until quite lately, almost the whole existing experimental evidence for the giant quadrupole (GQR) and monopole (GMR) isoscalar resonances has been provided by the electron and hadron probes, as the (e, e'), (p, p'), (d, d'), (a, a') inelastic scattering ex- periments. Now, due to the coincidence experiment (e, e' n) performed on il6Sn [a] and 208Pb [b] nuclei a new evidence for these resonances exists. In the case of 208Pb nucleus, the results of the (e, e' n) experiment are in a resonable agreement with the hadronic one, whereas in the case of 1105?i they disagree remarkably with the already existing evidence [c]. Especially important is the difference in the GMR resonance energy Ebr because of its connection with the nuclear incompressibility modulus K^: where m is the nuclear mass and < r2 > is the experimental root-mean-square radius. If one calculates KĄ for Ebr = 15.7 MeV taken from the (a, a') experiment [c], one gets /M = 126.7 MeV and for Ebr = 17.9 MeV obtained from (e, e' n) experiment, one gets K.\ - 164 MeV. . 197 Before a new experimental (e, e' n) evidence will be available for other nuclei, we can try to see whetherfch Baryon Semileptonic Decays P. ŻENCZYKOWSKI1 INP Cracow and Guelph University, Guelph, Canada We discuss small contributions to baryon semileptonic decays which provide correc- tions to the simplest SU(3)-symmetric formulas. In particular, we consider 1. - SU(3) symmetry breaking resulting from the wave function deformations due to s-u,d quark mass difference and 2. - the effects of the configuration mixing of S\rt and S\ states, originating from QCD hyperfine interactions. Both effects are treated in combination with form factor sup- pression effect which is operative if three-momentum transfer between initial and final hadron is nonzero. Our estimates are performed in the framework of the hadronic oscillator quark model. While the inclusion of s-u,d quark mass difference leads to unacceptable 5u/ ratio for the A —> peu semileptonic decay, the corrections due to configuration mixing do not lead to disagreement with the data. Better measurements of the E —» ntv and E —• Aet/ are needed if the choice is to be made between the stan- dard SU(3)-symmetric parametrization and the pattern of SU(3) breaking resulting from configuration mixing [43]. 198 Weak Radiative Hyperon Decays P. ŻENCZYKOWSKI1 INF' Cracow mid (!n Weak radiative hyperon decays (VVRHD) art.1 studied in an approach which combines the idea of vector-meson dominance with requirements of SU(Q)w symmetry connecting vector- and pseudoscalar -meson weak couplings to hyperons. In such an approach the data on iionleptouic hyperon decays determine the parity conserving WRHD amplitudes completely and suffice to fix two of three parameters needed to describe the parity violating amplitudes. The parity-conserving amplitudes are obtained from those of nonleptonic hyperon decays in two ways: 1. - in the pole model and 2. - by assuming that the parity-conserving part of the weak Hamiltonian transforms as A7. Both are considered since, although the two frameworks are theoretically close, their numerical predictions are fairly different. The only parameter that cannot be fixed from nonleptonic hyperon decays and which is needed for the description of parity violating amplitudes is determined from fits to all the branching ratios and asymmetries of WRHD measured so far. The fits strongly favour a substantial pos- itive asymmetry for the E~ -» E"? decay. The best fit ( x2f^DF = 7.9/7 ) is obtained with HJ;Ci transforming as A7 and photon -baryou coupling determined by experimental values of baryon magnetic moments. The corresponding asymmetry parameter is then predicted to be a = -}-0.6 [44,45]. Weak Nonleptonic Hyperon Decays P. ŻENCZYKOWSKI1 INP Cracow and Gnelph University, Guelph, Canada The influence of hadronic-loop effects on the SU(3) structure of the soft- pion contri- bution to the S-wave weak nonleptonic hyperon decays is studied in the framework of the Unitarized Quark Model. The effects considered originate from the interference of strong and weak amplitudes of the P-wave hyperon decays. When the baryon-pole model is used to describe the latter it is found that the quark sea generated by hadronic loops renormal- izes the sizes of the two independent SU(3) amplitudes away from their naive quark model ratio of f/d = -1 to f/d = -1.6. This is in remarkably good agreement with the phenomeno- logical estimate of the soft-pion contribution performed by Pham who, after subtracting 199 the terms violating the modified Lee-Sugawara relation, obtained (f/d)toft-pion — — 1.5 [46]. 4. PUBLICATIONS [1] W.M. Alberico, P. Czerski, V.R. Manfredi, A. Molinari: Collective Modes in a Slab of Interacting Nuclear Matter, Z. Phys. A338 (1991) 149 [2] R. Arvieu, P. Kamiński, M. Ploszajczak: Quantum Tunnelling in the Periodically Driven SU(2) Model, preprint GANIŁ P-91-18 (1991) [3] R. Arvieu, P. Rozniej, M. Ploszajczak: Phase. Space Structure of Simple Nuclear Model , preprint ISN-Grenoble (1991) [4] B. Badełek, K. Charchula M. Krawczyk, J. Kwieciński: Small x Physics, preprint DESY 91-124 (1991) [5] B. Badełek, J. Kwieciński: Shadowing in Inelastic Lepton-Deuteron Scattering, pre- print Warsaw Univ. IFD/3/91 (1991); to be published in Nucl. Phys.B [6] P. Bochnacki, A. Horzela, E. Kapuścik, J. Kempczyński: On the Generalization of Medvedev Approach to Classical Mechanics, preprint INP 1553/PH (1991), submit- ted to Phys. Rev. D [7] P. Bożek, Z. Burda, J. Jurkiewicz, M. Ploszajczak: Intermittency and Clustering in the One-Dimensional Lattice Gas Model, Phys. Lett. B271. (1991) 133 [8] P. Bożek, M. Ploszajczak, A. Tucholski: Finite-Size Effect in the Intermittency Anal- ysis of the Fragment Size Correlations, preprint GANIŁ P-91-16, Nucl. Phys. A in press [9] P. Bożek, M. Ploszajczak: Spatio temporal tntermittency in Ultrarelativistic Nuclear Collisions, Phys. Rev. C44 (1991) 1620 [10] P. Bożek, M. Ploszajczak: The Singular Multiparticlf. Correlations and the a—Model, Phys. Lett. B271 (1991) 243 [11] P. Bożek, M. Ploszajczak: Finite-Size Scaling in the Multiparticle Production, preprint GANIŁ P-91-23 [12] P. Bożek, M. Ploszajczak: Finite-Size Effect in Intermittency, Phys. Lett. B264 (1991) 204 [13] W. Broniowski, M.K. Banerjee, T.D. Cohen: Splitting of Neutron and Proton Electric Polarizabilities in a Chiral Soliton Model, Univ. of Maryland preprint 92-130 (1991) [14] W. Broniowski, A. Kotlorz, M. Kutschera: Quarks with a Pion Condensate - A New Phase of Matter, Acta Phys. Pol. B22 (1991) 145 200 [15] F. Caunata, J.-P. Dcdonder, L. Leśniak: Distortion of Hadron Wave Functions in Nuclear Matter, Nuovo Cim. 104A, (1091) 287 [10] F. Cannnta, J.-P. Dodunder, L. Leśniak: /o(975) Meson ani the KK Threshold Effects, contribution to the Eiirophysics Conference on High Energy Physics, CERN, Geneva, July 25 - August 1, 1991; preprint INP 1554/PH (1991) [17] F. Cannata, J.-P. Dcdonder, L. Leśniak: nn and KK Channel Coupling,II. The /o(975) Meson and the KK Threshold Effects, Orsay preprint IPNO-TH 91-91 (1991) [18] W. Czyż, A. Dyrek: Production of Hard Photons in Electron-Positron Annihilation into Hadrons, preprint TPJU 21/1991 (1991) [19] E.Etim. A. Malecki: Nucleon Form Factors in a VMD Model with Both Q2-and S- Channel Duality, II Nuovo Cim. 104A (1991) 531 [20] K. Golcc-Dieniat, Tli. W. Ruijgrok: Inte.grable Hamiltonian System in 2N-Dimensions Acta Phys. Pol. B22 (1991) 277 [21] A. Horzela, E. Kapuścik, J. Kempczyi'iski: Does Light Move Uniformly?, Physics Essays 5, in press . [22] A. Horzela, E. Kapuścik, J. Kempczyński: On the Galilean Covariance of Classical Mechanics, preprint INP 1556/PH (1991) [23]. A. Horzela, E. Kapuścik: Galilean Covariant Quantum Mechanics, Proceedings of II Winner Symposium, Goslar, 1991, in press [24] A. Horzela, E. Kapuścik, J. Kempczyński: On the New Notion of Mass in Classical Mechanics, Hadrouic Journal 14 (1991) 79 [25] A. Horzela, E. Kapuścik, J. Kempczyński: On Galilean Covariant Quantum Mechan- ics, preprint INP 1557/PH (1991) [26] E. Kapuścik: On Classical Electrodynaviics with Distribution - Valued Sources, pre- print JINR Dubna E2-91-272 (1991) [27] E. Kapuścik, A. Horzela: Nuzen li novyj obiekt v teorii gravitacji?, Proceedings of the conference "Gravitacjonnaja energia i gravitacjonnyje volny", preprint JINR Dubna P2-91-164 (1991) [2S] E. Kapuścik, A. Horzela: Classical Mechanics of Confined Particles, preprint JINR Dubna E2-91-477 (1991) [29] E. Kapuścik, J. Kempczyński, A. Horzela: Obobszczennyj princip ekvivalcntnosti Einsteina, Proceedings of the conference "Gravitacjonnaja energia i gravitacjonnyje volny", preprint JINR Dubna P2-91-164 (1991) [30} E. Kapuścik, J. Kempczyński, A. Horzela: DvizeUa li suet ravnomierno?, Proceedings of the conference "Gravitacjonnaja energia i gravitacjonnyje volny", preprint JINR Dubna P2-91-164 (1991) [31] E. Kapuścik, J. Kempczyński, A. Horzela: On the Galilean Mass of Bodies, Physics 201 Essays 5, in press [32] J. Kwieciński, A.D. Martin, P.J. Sutton: The. Small x Behaviour of the Gluon, Phys. Lett. B264 (1991) 199 [33] J. Kwieciński, A.D. Martin: Semihard QCD Expectations for Proton-(AntijProton Scattering at CERN, Tevatron and SSC Colliders, Phys. Rev. D43 (1991) 560 [34] J. Kwieciński, A.D. Martin, P.J, Sutton: QCD Predictions for the Behaviour of the Gluon Distributions at Small x, Phys. Rev. D44 (1991) 2640 [35] M. Kutschera, W. Broniowski, A. Kotlorz: Quark Matter with Pion Condensate in an Effective Chiral Model, Nuci. Phys. A525 (1991) 585c [36] M. Kutschera, W. Wojcik: Accretion-Induced Magnetic Field Decay and Polarized Protons in the Neutron Star Core, preprint INP 1555/PH (1991) [37] M. Kutschera, W. Wójrik: Spin Properties of Dense Matter and the. Origin of Mag- netic Field of Neutron Stars, preprint INP 1569/PH (1991) [38] A. Małecki: Elastic Scattering and Inelastic. Diffraction, preprint INP 1527/PH (1991) [39] A. Malecki: Inelastic Diffraction and Equivalence of States, Phys. Lett. B267 (1991) 523 [40] A. Małecki: Nuclear and Partonic Dynamics in High Energy Elastic Nucleus -Nucleus Scattering, Phys. Rev. C44 (1991) [41] M. Płoszajczak, A. Tucholski: Intermittency in Nuclear Multifragmentation, preprint GSI-90-40, Nucl. Phys. A in press [42] P.V. Pobylitsa, E. Ruiz Arriola, Th. Meissner, F. Gruemmer, K. Goeke, W. Bro- niowski: Static and Inertial Mass of the Nucleon in the Nambu-Jona-Lasinio Model and the Zero Point Energy, preprint RUB-TPII, Nov. 5, 1991, submitted to Phys. Lett. B [43] D. Strózik-Kotlorz: Parton Distribution in the Small x Region within LLx Approxi- mation, preprint INP 1552/PH (1991), to be published in Z. f. Phys.C [44] P. Zenczykowski: SU(3)-Symmetry Breaking and Configuration Mixing in Baryon Semileptonic Decays, Phys. Rev. D43 (1991) 2209 [45] P. Zenczykowski: Reanalysis of Weak Radiative Eypcron Decays in Combined Sym- metry and Vector-Dominance Approach, Phys. Rev.D44 (1991) 1485 [46] P. Zenczykowski: Weak Radiative Hyperon Decays and Vector-Meson Dominance, to appear in proceedings of the "Hadron-91" conference (Univ. of Maryland, College Park, U.S.A., Aug.12 -16, 1991,) [47] P. Zenczykowski: Weak Nonleptonic Hyperon Decays and Hadronic Loops, Guelph preprint GIPP-91-4 (1991), submitted to Phys. Row D 202 5. CONFERENCES AND SEMINARS X. ARTRU - University of Lyon, France 1. Transverse Spin, Department of Theoretical Physics, INP Cracow, October 1991. P. BOŻEK - graduate student 1. Structure of the Multiparticle Correlations, Theory Days, GANIL, Caen, FVance, May 1991, 2. L'analyse its fluctuations par la loi taillr.s finies, GANIL, Caen, France, December 1991. W. BRONIOWSKI 1. Quantum Physics in Chiral Models, University of Bochuin, Borhurn, Germany, Jan- uary 1991, 2. RPA in Quark Meson Systems, University of Bochum, Bochum, Germany, May 1991, 3. Dense Quark Matter antl Pion Condensates, Workshop on Nucleon Structure and Nucleon Resonances, Institute of Nuclear Theory, Seattle, August 1991. M. CERKASKI 1. Zastosowanie cięgtych symetrii do redukcji równań ewolucji. Grupa Galileusza (Appli- cations of Continuous Symmetry Groups to Evolution Equations. The Galileo Group in the N-Body Problem), Department of Theoretical Physics, INP Cracow, January 1991, 2. Collective Nuclear Dynamics vi'thin O(N-l) Invariant Approach, JINR, Dubna, April 1991, 3. Dyskusja kolektywnych pasm stacjonarnych w modelu Sp(6,R) (Classification of Col- leciive Stationary Bounds wititin Sp(6, R) Model) , Department of Theoretical Physics, INP Cracow, October 1991. P. CZERSKI 1. Niesymetryczna materia jędrowa (Asymmetric Nuclear Matter), Department uf The- oretical Physics, INP Cracow, April 1991, 2. Asymmetric Nuclear Matter in Neutron Stars, University of Torino, Torino, Italy, May 1991. W. CZYŻ 1. Promieniowanie elektromagnetyczne partonów (Electromagnetic Radiation of Partons) Department of Theoretical Physics, INP Cracow, March 1991, 203 2. Promieniowanie twardych fotonów w anihilacji e"*"e~ —• hadrony (Hard Photon Ra- diation in the e+e~ Annihilation into Hadrons), Department of Theoretical Physics, INP Cracow, October 1991. F. DÓRING - Ruhr-Universitat, Bochum, Germany 1. Regularization Dependence of the NFL Model, Department of Theoretical Physics, INP Cracow, March 1991. A. FASSLER - University of Tubingen, Germany 1. Grand Unification of the Forces and the Double (3 Decays, Department of Theoretical Physics, INP Cracow, April 1991. K. GOLEC-BIERNAT 1. Nierenormalizowalne teorie, pola (Nonrenormalizable Field Theories), Department of Theoretical Physics, INP Cracow, January 1991, 2. Sformułowanie Weyla mechaniki kwantowej a granica klasyczna (Weyl Formulation of Quantum Mechanics and the Classical Limit), Department of Theoretical Physics, INP Cracow, May 1991, 3. Fizyka matych x na HERZE (Small x Physics at HERA), Department of Theoretical Physics, INP Cracow, November 1991 and Department of High Energy Physics, INP Cracow, December 1991. F. GRUMER - Ruhr-Universitat, Bochum, Germany 1. Nambu-Jona-Lasinio Model, Department of Theoretical Physics, INP Cracow, March 1991. K. HELLER - Institute of Physics, Jagellonian University, Cracow 1. Lokalne sieci komputerowe (Local Computer Networks), Department of Theoretical Physics, INP Cracow, February 1991. A. HORZELA 1. Newtonowskie wyprowadzenie równań Maxwella czyli co oznacza słowo wspólzmienni- czość ( Feynman's Proof of Maxwell Equations, i.e. What Is ihe Meanning of "Co- variance"), Department of Theoretical Physics, INP Cracow, May 1991, 2. Koncepcja masy galileuszowskiej (The Concept of Galilean Mass), Department of The- oretical Physics, INP Cracow, December 1991. 204 M. JEŻA BEK • Higli Energy Physics Departinwit, INP Cracow 1. Fizyka kwarku, t (t- Quark Physics), Department of Theoretical Physics, INP Cracow, April 1991. P. K A MIŃSKI- graduate student 1. Large N Limit in Quantum Mechanics, GAN1L, Caen, France, January 1991, 2. Quantum Tunnelling in the Driven SU(2) Model, GANIL, Caen, France, May 1991. E. KAPUŚCIK 1. Galilean Covariant Quantum Mechanics, II Wigner Symposium, Goslar, Germany, June 1991. M, KUTSCHERA 1. Domieszka protonów w materii neutronowej: rola sprzężenia z fononami (Proton Im- purities in Neutron Matter: The Role, of Coupling to Phonons ), Department of The- oretical Physics, INP Cracow, February 1991, 2. Skondensowana materia barionowa w gwieździe neutronowej (Condensed Baryon Mat- ter in a Neutron Star), Institute of Theoretical Physics, Warsaw University, Warsaw, April 1991, 3. Spin Properties of Dense Matter and Magnetic Fields of Neutron Stars, School of Theoretical Physics, Szczyrk, September 1991, 4. StabilnoSC gwiazd kwarkowych (Stability of Quark Stars), Department of Theoretical Physics, INP Cracow, November 1991, 5. Czy rozbłyski promieniowania j pochodzą od zderzających się gwiazd kwarkowych? (Do *y~Ray Bursts Gome from Colliding Quark Stars?), Institute of Physics, Jagellonian University, Cracow, November 1991. J. KWIECIŃSKI 1. Rozpraszanie głębokonieelastyczne ep w granicy x —• 0 ( Deep Inelastic ep Scattering in the x —> 0 Limit), Department of Theoretical Physics, INP Cracow, Jamiary 1991, 2. Parion Distributions at Small x, XXVI Rencontre de Moriond, Les Arcs, Frajnce, March 1991, 3. Funkcje rozkładu partonów w granicy m-ałych x i eksperymenty na akceleratorach HERA, SSC i HC (Parton Distributions in the Sm.all x Limit and Experiments on the HERA, SSC and LHC Colliders), Institute of Theoretical Physics, Warsaw University, Warsaw, May 1991, 205 4. Funkcje rozkładu gluonów -•) chromodynamice kwantowej (Gluon Distribution Func- tions in Quantum Chromodynamics), Institute of Theoretical Physics, Warsaw Uni- versity, Warsaw, May 1991, 5. 0 regule sum Gottfried^, w nieelastycznym rozpraszaniu leptonów na nukleonie (The Gottfried Sum Rule in Inelastic Lepton-Nucleon Scattering), Department of Theoret- ical Physics, INP Cracow and Institute of Physics, Jagellonian University, Cracow, October 1991. L. LEŚNIAK 1. /of 975) Meson and the KK Threshold Effects in Its Decay, Department of Theoretical Physics, INP Cracow, March 1991, 2. Mezony skalarne i efekty progowe KK (Scalar Mesons and the KK Threshold Effect*), Institute of Physics, Jagellonian University, Cracow, May 1991, 3. Relatywistyczne efekty w zderzeniach KK (Relativistic Effects in the KK Collisions), Department of Theoretical Physics, INP Cracow, October 1991. A. MAIECKI 1. Dyfrakcja i równoważność stanów (Dyffraction and Equivalence of States), Depart- ment of Theoretical Physics, INP Cracow, April 1991, 2. Nieelastyczna dyfrakcja jądrowa (Nuclear Inelastic Diffraction), Department of rT1hc oretical Physics, INP Cracow, November 1991. A. D, MARTIN - University of Durham, Durham, England 1. Parton Distributions and Small x, XXXI Zakopane School of Theoretical Physics, Zakopane, June 1991. H. MUTHER - University of Tubingen, Tubingen, Germany 1. Mesons and Nucleons in a Nuclear Medium, XXXI Zakopane School oi." Theoretical Physics, Zakopane, June 1991. M. A. NOWAK - Institute of Physics^ Jagellonian University, Cracow 1. Model próżni instantonowej dla QCD (Instanton Vacuum Model of QCD), Department of Theoretical Physics, INP Cracow, February 1991. M. PŁOSZAJCZAK 1. Fractal Structures in Nature, GANIL, Caen, France, February 1991, 206 2. Phuxr.-Trunjitionx and Critical Phr.iwmf.na in Heavy-Ion Collisions, GANIL, Cam, France, MIUT.1I 1991, • 3. Non-Statistical Fluctuation* in Hmvy-lon Collisions, IPN-Orsay, France, March 1991, 4. Intr.rmitte.ncy and Fluctuations in Heavy-Ion Collisions , Laboratoirc National Sa- tiirne, Gif-sur-Yvette, Franc*, March 1991, 5. The Volume Conserving Pairing (special seminar devoted to the memory of Professor Z. Bochnacki), Jagellonian University, Cracow, Poland, April 1991, 6. lnte.rmitte.ncy in Heavy-Ion Collisions, 29th Spring School of Nuclear Physics, Holzhau, Germany, April 1991, 7. Intermittency in Ultrarelativistic Collisions, GSI-Darmstadt Workshop, Darmstadt, Germany, May 1991, 8. Kinetic Theories for Heavy-Ion Collisions (Table Ronde), Orsay, France, May 1991, 9. Fluctuations in Nuclear Collisions, Giens, France, May 1991, 10. Exclusive. Analysis of the. Fluctuations in the Heavy-Ion Collisions, Int. Conf. on Heavy-Ion Collisions, Kanazawa, Japan, June 1991, 11. Critical Phenomena in Nuclear Collision.!, HMl-Berlin, Germany, June 1991, 12. Intermittency in the Particle Production and in the Nuclear Fragmentation, Tours, France, August 1991, 13. Non-Statistical Fluctuations in Fragmentation Process, Grenoble, France, November 1991. A. RADOSZ - Physics Department, Technical University, Wroclaw 1. Ściśle, rozwiązywalny model przejścia fazowego (Rigorously Soluble Model of the Phase Transition), Department of Theoretical Physics, INP Cracow, December 1991. D. STRÓZIK-KOTLORZ graduate student 1. Parian Distributions in the Small x Region viithin LLx Approximation, QCD Work- shop, University of Lund, Lund, Sweden, May 1991. P. ŻENCZYKOWSKI 1. Weak Radiative. Hyperon Decays and Vector-Meson Dominance., contributing talk, HADRON-91 Conference, University of Maryland, College Park, Maryland, USA, August 1991. 207 6. HABILITATIONS Marek KUTSCHERA - Chiral Models of Dense Matter and Its Magnetic Properties, 13 May 1991 7. Ph.D. THESES Dorota STRÓZIK-KOTLORZ - QCD Analysis of Parton Distribution Functions in the Small x Region, 3 September 1991, supervisor - professor J. Kwieciński 8. M.Sc. THESES Robert KAMIŃSKI- Analiza sprzężonych kanałów nn i A*A' z uwzględnieniem relatywisty- cznych efektów w kanale TCJT (KIT and A"A' Coupled Channel Analysis Including Relativistic Effects in the mr Channel), June 17, 1991, supervisor - doc. dr hab. L. Leśniak 9. LECTURES LECTURES FOR STUDENTS OF PHYSICS AND MATHEMATICS AND SCIENTIFIC STAFF 1. Prof. J. Kwieciński - Introduction to Nuclear and Elementary Particle Physics, lectures for undergraduate physics students at the Cracow Pedagogical University, 2. Prof. J. Kwieciński - Deep Inelastic Processes, series of lectures delivered at the Institute of Nuclear Physics in Jtilich, Germany, June 1991, 3. Dr M. Ploszajczak - individual lectures: Round Table on Nuclear Fragmentation (Febr. 1991) GANIL, Caen, France; IPN-Orsay, Paris, France, March 1991; CEN- Saclay, Paris, France, April 1991; IPN-Grenoble, France, October 1991; IPN- CNRS, Univ. Nantes, France, November 1991. 4. Dr P. Zenczykowski - Subatomic Physics, lectures for undergraduate students of physics, University of Guelph, Guelph, Cauada, Winter 1991, 5. Dr P. Zenczykowski - Introductory Physics, lectures for undergraduate students of physics, University of Guelph, Guelph, Canada, Spring 1991. 208 10. GRADUATE STUDENTS Piotr BOŻEK Piotr KA MIŃSKI Andrzej K0TL0RZ Dorota STRÓZIK-KOTLORZ 10. VISITING SCIENTISTS A. FA ES SL ER - Department of Theoretical Physics, University of Tubingen, Tubingen, Germany, April 1991 F. GRUMER - Department of Theoretical Physics, Ruhr-Universitafc Bochum, Bochum, Germany, March 1991 R. C. HWA • Institute of Theoretical Science, University of Oregon, Eugene, U.S.A., June 1991 J.-P. MAILLET - Division de Physique Theorique, Institut de Physique Nucleaire, Orsay, France, June/July 1991 A.I). MARTIN - Department of Physics, University of Durham, Durham, England, June 1991 //. MUTHER IVpnitmenl of Theoretical Physics, University of Tubingen, Tubingen, Germany, April 1991 209 Department of High Energy Physics H 1 , i High Energy Physics Laboratory Head Prof. T.Coghen The activity of the Laboratory is concentrated on research in the field of elementary particle physics of relativistic nuclei, cosmic ray physics and the research and develop- ment of detectors for high energy physics experiments. Fields of interest are in particular structure and fragmentation function analysis, test of Standard Model of electroweak in- teractions, measurement of life time and production mechanism of c and b - particles, hadron and lepton interactions with nuclei, radiative corrections, nucleus-nucleus interac- tion at very high energy — search for quark-gluon plasma, characteristics and composition of primary cosmic radiation. The laboratory consists of: the Eletronic Particle Detector Group (EPD) headed by Prof. K. Rybicki, the Experimental Elementary Particles Physics Group ( previously Track Chamber Group TC ) headed by Prof. A. Eskreys, High Energy Nucleus Interactions Group ( previously Emulsion Group ) headed by Prof. R. Hołynski, Theoretical Group headed by Prof. K. Zalewski and computing electronic and technical support groups as well as a skeleton administration. The previous TC and Emulsion Group are at present also involved in modern electronic experiments. The work in laboratory is carried out in close collaboration with High Energy Physics Gropu from the Faculty of Physics and Nuclear Techniques of the Academy of Mining and Metallurgy and the Theoretical Department of the Institute of Physics of the Jagiellonian University in Cracow. A weekly common seminar for this high energy physics community takes place in the laboratory. Close contacts in research in some joint projects such as the DELPHI, the ZEUS, NA22 and NA35 experiments are maintained with Warsaw institutions: the Institute of Nuclear Problems and the Institute of Experimental Physics of the Warsaw University. As modern high energy physics experiments are based on a few big accelerators ( SPS, LEP, TEVATRON, HERA ) and require enormous means - technical, man power and financial - the research can only be carried out in the framework of large international collaborations. These are listed below: List of Experiments (preparation,running and analysis stage) and Internotional Collaborations + EPD -group: DELPHI (e e~ interaction at LEP, ECM - lOOGe^) CERN NA32 {np at 200 GeV) CERN HI [e^p interactions 30 GeV x 820 GeV at HERA) DESY Crystal Ball (e+e~ interactions at DORIS ECM = WGeV) DESY 211 TC group: ZEUS (eJjj interactions 30 GeV x 820GeV) DKSY E665 (H+P interactions at 500 GeV/TEVATRON) Fermilab NA22(EHS) (ir+,/f+,p- -p,Al,Au interactions, 250 GeV) CERN WA59 ( v *re.jH interactions, 10-200 GeV) CERN NA35 (160 and 325 interactions on nuclear targets at 60 and 200 GeV/nucleon, SPS) CERN Emulsion group: JACEE (Super high energy cosmic ray interactions in balloon borne emulsion chambers GRAND (Extensive air shower array at Bea level) KLMM (160,325 ,nSi - emulsion interactions at 15, 80, 200 GeV/nucleon) BNL, CERN KLMT (7r~ - emulsion at 525 GeV ) Fermilab The High Energy Physics Laboratory participates in research and development work for the Large fladron Collider (LHC) to be constructed in the LEP - tunnel at CERN. TeamB (comprising also engineers from other divisions of the institute) work on the de- velopment of detectors, software for experiments and of the accelerator. DELPHI Collaboration Iowa State Univ., Ames (USA); Univ, Instelling Antwerpen, Wilrijk (BL); Univ. of Athens (Git); Univ. of Bergen (N); INFN Bologna (I); College de France, Paris (F); DPhPE, Centre d'Etudcs Nucleates de Saclay, Gif/Yveite (F); European Organisation for Nuclear Research, Genewa (CH); Univ. Federal do Rio de Janeiro, Rio de Janeiro (BR); Centre de Recherches NucleoireB, Strasburg (F); NCSR Demokiitos, Athens (GR); INFN Genova (I); Univ. of Helsinki (FIN); Inat. for Hochcnenergiephyoik, Wien (A); Inst. de Fisica Corpuscular, Univ. of Valencia, Burjassot (E); Inter-Univ. Inst. for High Energies ULB/VUB, Brussels (B); Inst. de Phys. Nucleaire Lyon I, Vilieurbanne (F)j Inst. des Scienceu Nuclćeirea, Grenoble (F); Joint Inst. for Nucl. Research, Dubna; Univ. Karlsruhe (D); Inat. of Nucl. Phys., Cracow (PL); Univ. Federal do Rio de Janeiro, (BR); Lab. de i'Accelerateur Line"aire OrBay, Paria (F); Lab. de Instrumentacao e Fisica Experimental de Particular Lisboa (P); Univ. of Liverpool, (GB); Lab. de Physique Nucleaire et de» Hautes Energies, Paris, (F); Univ. of Lund, (S); INFN Milano, (I); Service de Physique den Particules Elementaires Univ. de Mons-Hainaut, Mons, (B); Niels Bohr InBt., Copenhagen, (DK); Nat. Inst. for Nucl. Phys. and H.E. PJiya. Amsterdam, (NL); National Technical Univ., Athens, (GR); Univ. of Oslo, (N); Univ. of Oxford, (GB); INFN Padova, (I); Rutherford Appleton Lab., Didcot, (GB); Rhone Alpes Provence, Grenoble , Lyon, Marseille, (F); Univ. of Roma II "Tor Verg&ta", Roma, (I); Inst. Superiore di Sanita, Roma, (I); Facultad de Ciencjas, Univ. de Cantabria, Santander, (E); Inat. for High Energy Phyaica, Protvino j Univ. of Stockholm, (S); INFN Torino, (I); INFN Trieste, (I); INFN Udine, (I); 1SV, Dept. of Radiation Scicnceo, Uppsala, (S); Inat. Nuclear Studies and Univ. of Warsaw, (PL); Fnchbereich Phyoik, Gesamthochschule, Wi-ppertal, (D); 212 NA32 National Inst. for Nucl. and High Energy Phys. NIKHEF, Amsterdam (NL); H. H. Willa Phys. Lab., Univ. of Bristol (GB); CERN; Inst. Nucl. Phys., Cracow (PL); Max-Planck-Inst., Munich (D); Ruther- ford Appelton Lab. Chilton, Didcot (GB); Valencia Univ.(I); HI Antwerpen Univ.,(B); Brussels Univ. libre and vrye,(B); CEN Saclay,(F); Davies Univ., DESY,(D); Dortmund Univ.,(D); Ecole Polytechnique (Palaiseau),(F); ETH (Zurich),(CH); Glasgow Univ.,(GB); Hamburg Univ. (1, and 2. Institute),(D); Institute of Nuclear Physics Cracow,(PL); Institute of Physics, Prague,(CSSR); Institute of Experimental Physics, Kosice,(CSSR); Institut fur HEP Zeuthen,(D); INFN Roma,(I); Lancaster Univ.,(GB); Liverpool Univ.,(GB); Lund Univ.,(S); Manchester Univ.,(GB); ITEP (Moscow), Lebedev Physics Institute (Moscow), MPI (Mtinchen),(D); LAL Oisay,(F); P. & M. Curie Univ.(Paris),(F); RWTH Aachen (1. and 3. Institute) , (D); Rutherford Appleton Lab.,(GB); Wuppertal Univ.,(D); Zurich Univ. (CH); Crystal Ball Dept. of Phys., Harvard Univ., Cambridge MA (USA); Inst. oi'Nucl. Phys., Cracow (PL); Phys. Inat. der Univ. Erlangen-Niirnberg (D); Dept. of Phys, Univ. and Instituto Nazionale di Fisica Nuceare INFN, Firenze (I); DESY Hamburg (D); Inst. ff Eksperimentalphysik der Univ. Hamburg (D); National Inst. for Nucl. and High Energy Phys. NIKHEF, Amsterdam (NL); Princeton Univ. Princeton NJ (USA); SLAC Stanford CA (USA); Dept. of Phys. Stanford Univ., Stanford CA (USA); Phys.Inst. der Univ. Wiirzburg (D); ZEUS National Inst. for Nucl. and High Energy Phys. NIKHEF, Amsterdam (NL); Instituto di Fisica, Univ. DeH'Aquila (I); Argonne National Lab. ANL Argonnc IL (USA); Phys. Dept., Virginia Polytcch. Inst., Blacksbourg VA (USA); Dipartimento di Fisica, Univ. di Bologna (I); Phys. Inst. der Univ. Bonn (D); H. H. Willa Phys. Lab., Univ. of Bristol (GB); Dept. of Phys., Ohio State Univ., Columbus OH (USA); InBtituto di Fisica, Univ. delle Calabrie, Cosenza (I); Ins'., of Nucl. Techniques of the Academy of Mining and Metallurgy, Cracow (PL); Inst. of Nucl. Phys., Cracow (PL); Rutherford Appelton Lab. Chilton, Didcot (GB); Phys. Dept., York Univ. di Firenze (I); ENEA Roma, Lab, Nazionale di Frascati (I); Instituto Nazionale di Fisica Nucearc INFN, Lab. Nazionale di Frascati (I); Fakultat ff Physik der Universitat Freiburg (D); DESY Hamburg (D); Inst. fiir Eksperimentalphysik der Univ. Hamburg (D); Phys. and Astronomy Dept. Univ. of Iowa, Iowa (USA); Nevis Lab. and Phys. Dept. Columbia Univ. Irwington N.Y. (USA); Inst. ff Reaktorentwickung, Kernforschungsanlage Jiilich (D); Dipartimento di Fisica, Univ. di Lecce (I); Dept. of Phys. Imperial College, London (GB); Phys. and Astronomy Dept., Univ. College, London (GB); Dept. of Phys., Univ. of Wisconsin, Madison WI (USA); Dept. de Fisica Teoretica, Univ. Autonoma de Madrid (E); Instituto di Fisica, Univ. di Milano (I); Phys. Dept..McGill Univ., Montreal (CAN); Dept. of Phys. Carleton Univ., Ottawa (CAN); Dept. of Nucl. Phys., Univ. of Oxford (GB); Dipartimento di Fisica, Univ. di Padowa (I); Dipartimento di Fisica, Univ. di Palermo (I); Dept. of Nucl. Phya.,Weizmann Inst. Rehovot (Israel); Instituto di Fisica, Univ. "La Sapienza", Roma (I); Inst. for Particle Phys. Univ. of California Santa Cruz CA (USA); Phys. Inst. der Univ. GHS Siegen (D); Dept. of Phys. Tokyo Metrop. Univ., Tokyo (J); Inst. for Nucl. Study, Univ. of Tokyo (J); Instituto di Fisica, Univ. di Torino (I); 213 E885 Aigonne National Laboratory, Argonnc, IL (USA); University of California, San Diego, La Jolla, CA (USA); Institute of Nuclear Physics, Cracow, (PL); Institute of Nuclear Physics and Technology, Academy of Mining and Metallurgy, Cracow, (PL); Fermi National Accelerator Laboratory, Batavia, IL (USA); Albert-Ludwigs-Univcrsitat, Freiburg i. Br.,(D); Harvard University, Cambridge, MA (USA); University of Illinois at Chicago, Chicago, IL (USA); University of Maryland, College Park, MD (USA); Mas- sachusetts Institute of Technology, Cambridge, MA (USA); Max-Planck-Institut fur Phyaik und As- trophysik, Milnchen,(D); University of Washington, Seattle, WA (USA); Universitat-Gesamthochschule Wuppertal, Wuppertal 1,(D); Yale University, New Haven, CT (USA); NA22(EHS) Univ. Instclling Antwcrpcn, Wilryk, (B); Inter-Univ. Inst. for High Energies, Brussels, (B); Inst. fur Hochenergiephysik, Berlin, (D); Inst. of Phys. and Nucl. Tech. of the Academy of Mining and Metal- lurgy Cracow, (PL); Inst. of Nucl. Phys., Cracow, (PL); WA 50 AthenB Dcmokritos (GR); Bari Univ. (I); Birmingham Univ.(GB); Inter-University Instytut for High Energies, Brussels (B); CERN ; Pliys. and Astronomy Dept., Univ. College, London (GB); Dept. of Phya. Imperial College, London (GB); Max-Planck-Inst., Munich (D); Dept. of Nucl. Phys., Univ. of Oxford (GB); Palaiscau Ec. Poly. L.P.N.H.E. (F); Rutherford Appelton Lab. Chilton, Didcot (GB); Sacky CEN DPhP (F); Iniit. of Nucl. Phys., Cracow (PL); NA 35 Physicj Dept., Univ. of Athens (GR); INFN, 5ez. Bari and Dipartimento di Fisica, Univ. di Bari (I); Lawrence Berkeley Lab.(GB); CERN; Inst. of Nuclear Physics Cracow (PL); GSI Daimstadt (D); Fach- bereich Pliysik, Univ. Frankfurt (D); Fakultat fur Physik, Univ. Marburg (D); Max-Planck-Institut fur Physik, Miinchen (D); Inst. of Experimental Physics, Univ. of Warsaw (PL); Inst. of Nuclear Studies, Warsaw (PL); Rudjcr Boskovic Inst., Zagreb (YU); JACEE Inst. of Nucl. Phys., Cracow, (PL); Inst. for Cosmic Ray Research, Univ. of Tokyo, (J)j Dept. of Phys., Hiroshima Univ., Hiroshima, (J); Dept of Phys., Kobe Univ., Kobe, (J); Kobe Women's Junior, College, (J); Gkayama Univ. of Science Okayama, (J); Univ. of Alabama in Huntsville LA, (USA); Dept of Phys. and Astronomy, Luisiana State Univ., Baton Rouge,LA, (USA); Space Science Lab., NASA Marshall Space Flight Center, Huntsville LA, (USA); Dept. of Phya., Univ. of Washington, Seattle, WA, (USA); GRAND Inst. of Nucl. Phys., Cracow, (PL); Depfc. of Phys., Univ. of Notre Dame, Notre Dame, (USA); 214 KLMM Inst. of Nuci. Phys., Cracow, (PL); Luisiana State Univ., Baton Rouge,LA, (USA); Univ. of Minnesota, Minneapolit, MN, (USA); Inst. of Theoretical and Experimental Phys., Moscow, Russia; KLMT Inst. of Nucl. Phys., Cracow, (PL); Luiaiana State Univ., Baton Rouge,LA, (USA); Lebedev Phys. Inat., Moscow, Russia; Phys. Techn. Inst. Tashkent, Uzbekistan; Research personnel Jerzy Bartke, Prof. Stanisław Mikocki, Dr. Grazyrxa Bąk-Zalewska, Dr. Bronisław Nizioł, Dr. Piotr Białas, M.Sc. Grażyna Nowak, Dr. Jacek Błocki, Dr.Eng, Krystyna Olkiewicz, Dr. Andrzej Bożek, M.Sc. Andrzej Olszewski, M.Sc. Alfred Budziak, M.Sc. Krzysztof Pakoński, Dr. Wojciech Burkot, M.Sc. Henryk Pałka, Dr. Krzysztof Cetnar, M.Sc. Bogdan Pawlik, Dr. Janusz Chwasiowski, Dr. Grzegorz Polok, Dr. Tomir Coghen, Prof. Maria Różańska, Dr.hab Antoni Dwuraźny, Dr. Krzysztof Rybicki, Prof. Andrzej Eskreys, Prof. Iwona Sakrejda, Dr, Jan Figiel, docent Dr.hab Andrzej Sobala, M.Sc. Szymon Gadomski, M.Sc. Piotr Stefańeki, M.Sc. Ewa GładyBz-Dziaduś, Dr. Piotr Stopa, Dr. Lidia Gorlich, Dr. Monika S żarska, Dr. Leszek Hajduk, M.Sc. Adam Trzupek, Dr. Zbigniew Hajduk, Dr. Michał Turała, Prof. Roman Hołyński, Prof. Jacek Turnau, Dr.hab Stanisław Jadach, docent Dr.hab Zbigniew Wąs, Dr. Zbigniew Jakubowski, Dr. Barbara Wilczyńska, Dr. Paweł Jalocha, M.Sc. Henryk Wilczyński, Dr. Marek Jeżabek, docent Dr.hab Mariusz Witek, Dr. Alina Jurak, Dr. Marcin Wołter, M.Sc. Bartłomiej Kisielewski, Dr. Władysław Wolter, Dr. Marek Kowalski, Dr. Barbara Wosiek, Dr.hab Mieczysław Krasny, Dr. Krzysztof Woźniak, Dr. Tadeusz Lesiak, M.Sc. Maciej Zachara, Dr. Bogusław Machowski, M.Sc. Eng. Kacper Zalewaki, Prof. Piotr Malecki, docent Dr.hab Leszek Zawiejski, Dr. 215 Technical personnel Jerzy Andruezków, M.Sc. Eng. Danuta Krzysztoń Lucyna Antosiewicz Anna Łasa Witold Apostolski Lech Lasocki, M.Sc. Eng. Maria Brożyna, Eng. Marian Lemler, M.Sc, Eng. Ewa Bukała Halina Łydka Kazimiera Chudoba Bogdan Madeyaki, Eng. Janina Czajka Paweł Małota Witold Daniluk, Eng. Mieczysława Maniecka Anna Dąbrowska, M.Sc. Jerzy Michalowski, Eng, Bogdan Dąbrowski Maria Miernik, M.Sc. Marian Despet Zbigniew Natkaniec, M.Sc. Eng. Dorota Erbel Krzysztof Oliwa, Eng. Danuta Pilipiak Andrzej Paleta Andrzej Florek Maria Pieczora Bogusław Florek Anna Polarska Kazimierz Gałuszka, M.Sc. Eng. Stanisław Róg Edward Górnicki, Eng. Fryderyk Salek Małgorzta Hajduk Anna Stobierzanin-Aleksandrowa Jerzy Halik, M.Sc. Eng. Zdzisław Stopa Kazimiera Hebenstreit Andrzej Strączek Włodzimierz Janczur, M.Sc. Eng. Mieczysław Stręk Piotr Jurkiewicz, M.Sc. Eng. Jan Węgrzyn Żona Kawula Wojciech Wierba, M.Sc. Eng. Witold Kita Tadeusz Wojaa Andrzej Kotarba, M.Sc. Wiktor Żabiński Marianna Kowalczyk In 1991 out of the 108 ntaff members five are working on part-time basis. 24 scientists and engineers spent more than 6 months on leave of absence, all working 'in aitu' in experiments in which the laboratory is involved. 216 The DELPHI experiment ^ Cracow DELPHI group: Z. HAJDUK, P. JAŁOCHA, P. KAPUSTA, K. KORCYL, W. KRUPIŃSKI, J. MiCHAŁOWSKi, B. MURYN, K. PAKOŃSKI, H. PAŁKA, G. POLOK, K. RYBICKI, M. TURAŁA, A. ZALEWSKA engineers and technicians contributing to detector projects: A. ADAMSKI, A. FLOREK, B. FLOREK, K. GAŁUSZKA, T. GDAŃSKI, M. KAJETANOWICZ, A. PALETA, S. RÓG, M. STODULSKI, Z. STOPA, A. STRĄCZEK physicists who recently joined DELPHI: A. BUDZIAK, T. LESIAK, M. WITEK DELPHI (Detector for Electrons, Leptons, Photons and Hadrons Identification) is one of the four multi-purpose detectors installed on the LEP accelerator at CERN. It is used to study e+e~ interactions at the energies close to the mass of the Z° boson. Its perspective view and a list of the components is presented on Figure 1. The DELPHI experiment is run by more than 400 physicists from more than 40 sci- entific centers in Europe, United States and Brazil. Two Polish groups: one from the Institute of Nuclear Physics in Cracow and the other one from the Institute of Nuclear Problems in Warsaw and from the Warsaw University are among them. The 1991 was the third year of running LEP. Since April till November the DEL- PHI detector has collected about 300.000 Z°'s, which was twice as much as the data collected during the runs in 1989 and 1990. All the 1991 data have been collected using the upgraded, three-layered Vertex Detector, completed just before the run. The BRICH detector, dedicated to the hadrons identification in the central part of DELPHI, has been included into the data acquisation for the last 70.000 Z°'s. Both these detectors are the important tools for the analysis of the short-lived particles containing the heavy quarks 6 and c. The relatively strong couplings of the Z° to bb and to cc pairs cause that physics of heavy quarks is of a great interest for the LEP experiments. The DELPHI detector seems to be well equipted to do it. The analysis of the data collected in 1990 was the second main activity of the DEL- PHI collaboration in 1991. It covered a wide spectrum of the interesting problems like a determination of the parameters of the Z° boson, studies of its electroweak properties, searches for the Higgs and the other new particles, checks of the QCD and of the different fragmentation models and first studies related to the heavy quark physics. The results are described in seventeen papers (see the list of references below), which appeared as the CERN preprints and were submitted to the publication in Physics Letters, Nuclear 217 Physics and Zeitschrift fiir Physik. Five of them are already published, the rest should be published soon. In addition, four papers submitted to the publication in 1990, were published in 1991. We will discuss more in detail two studies: a measurement of the lifetime of the r lepton [lj and a measurement of the average lifetime of the B hadrons [2]. They started a. new category of the measurements in DELPHI, based on a high precision of the track extrapolation to the interaction or decay vertex. This precision was achieved due to a presence of the two-layered Vertex Detector during the data taking in 1990. At that time DELPHI was the only LEP experiment having a properly working silicon vertex detector. In both these analyses tracks with the associated hits in the Vertex Detector were required. It allowed us to get much narrower impact parameter resolution functions than in the other LEP experiments. This reduced the contribution to the systematic error related to the uncertainty of the resolution function for the lifetime measurements. A good vertex detector also allowed us to perform two independent measurements of the average lifetime of B-hadrons. Besides the analysis based on leptons from the semileptonic decays of the heavy quarks, all charged particles from the hadromc Z° decays have been used to determine it. Figure 2 shows the impact parameter distribution for hadrons on which this measurement was based on. An excess of the tracks with the positive impact parameter over those with the negative impact parameter indicates a presence of the particles decaying outside the primary interaction vertex. A comparison of the observed distribution with the distribution obtained from the Monte Carlo program, assuming different lifetimes of these particles, allows to determine their lifetime. The value obtained by DELPHI for the lifetime of the r lepton is [1] r,au = 314 ± 23(stat.) ± 9(syst.)fa and the value obtained for the average lifetime of the B-hadrons is [2] rB = 1.28 ± O.lQps. The Cracow group participates in three detector projects of DELPHI: the Vertex De- tector, the Inner Detector and the RICH detectors. There are more than twenty physicists, engineers and technicians involved full-time or part-time in these projects. As was already mentioned, the Vertex Detector appeared to be a great success. We participated in this project from the very beginning. For the 1991 upgrade the Cracow group built up the power supplies for the detectors and the electronics, was responsible for the data acquisition programs and participated in the development of the off-line analysis programs. Figure 3 shows a display of a typical event Z° —> hadrons as given by the Vertex Detector on-line event display program, written by a member of the Cracow team. 218 The Inner Detector of Delphi consists of two parts: Jet Chamber and Trigger Lay- ers. The Trigger Layers has been designed, prototyped and built up in Cracow. Their purpose is to supply trigger information in the R — (j) and the R — z planes, to help in resolving left-right ambiguities in the Jet Chamber and to measure the z-coordinate of tracks. During first three years of operation the trigger derived from the Inner Detector became one of the crucial parts of the so called "Track Trigger" in both a first and a second stage of the Delphi triggering scheme. Its measured efficiency for hadronic events is 100 % and for leptonic events ;s 99.8 %• The Cracow team has contributed also to the read-out of Inner Detector writing the on-line embedded software for the Fastbus read-out electronics. Monitoring programs for the on(off)-lin.e tests of the detector performances have been written by us as well. The Cracow group has been responsible for detector current operations during the running periods in 1989 - 1991. A partial off-line event dis- play with information from the Vertex Detector and the Inner Detector is shown in Fig. 4. The RICH (Ring Imaging CHerenkov) counters decide on the uniquenes of the DEL- PHI detector as compared to the other LEP detectors. Their purpose is the hadron (K, K and p) identification through the measurements of the Cherenkov angle of the pho- tons which are emitted along the hadron's path in the detector. The Cracow group has contributed to a design and a construction of both Barrel and Forward RICH'es. Spe- cial tooling has been designed for assembly of photon detectors made out of biggest in the world quartz plates. The vessel containing Forward RICH gaseous radiator, made of complex sandwich materials of very low weight and at the same time very strong, was constructed in Cracow in cooperation with a local industry. The Cracow group has also contributed to the complex off-line analysis programs of the RICH detectors. Especially at the beginning of these projects the Monte Carlo studies helped to optimize the photon detectors and the whole detector configuration. Due to their complicated construction and substantial cost the RICH'es had some delay. As was mentioned, the Barell RICH was used for physics only at the end of the 1991 data taking period. The data are now being analyzed. The Forward RICH has been staged and only 1/12 was taking data in 1991. The hard effort has payed off, however, and in 1991 both RICH detectors showed the reconstructed Cherenkov rings for the particles coming from Z° decays. References [1] P. Abreu et al., A Measurement of the Lifetime of the Tau Lepton, CERN-PPE/91- 115, Phys. Lett. B267 (1991) 422. [2] P.Abreu et al., Measurement of the Average Lifetime of B Hadrons, CERN-PPE/91- 131, Submitted to Zeit. Phys. C 219 Figure 1: Perspective view of the DELPHI detector. 1 = Vertex Detector, 2 = Inner Detector, 3 = Time Projection Chamber (TPC), 4 = Barrel Ring Imaging Cherar.kov Counter (RICH), 5 = Outer Detector, 6 = High Density Projection Chamber (HPC), 7 = Superconducting Solenoid, 8 = Time of Flight Counters (TOF), 9 = Hadron Calorimeter, 10 = Barrel Muon Chambers, 11 = Forward Chamber A, 12 = Small Angle Tagger (SAT) = Luminosity Monitor, 13 = Forward RICH, 14 = Forward Chamber B, 15 = Forward Electromagnetic Calorimeter, 16 = Forward Muon Cham- bers, 17 = Forward Scintillator Hodoscope, the Very Small Angle Tagger (VSAT) falls outside the view, 220 £ (A O O 10 r 1 ? Impact Parameter tcm] Figure 2: Impact parameter distribution of hadronic tracks in the selected hadron sample The points represent the data. The solid histogram shows the Monte Carlo simulation giving the best fit and corresponding to TB = 1.27 ps. 221 uVertex view from +Z side R&/2U46 Ev«u 339 1991-05-02 100 ADC Figure 3: Display of the event hadrona given by the Vertex Detector on-line event display 222 TO TE TS TK TV ST PA DELPHI Interactive Analysis IS 0 HH 0 ' 0 0 Act Beam: CJ.6 CeV Pud" 7499 t:AS : 26-Mdr-l99O (152) I 01 , 01 ( HI ( 01 ( 0) ( 01 0 0 0 •> 0 0 0 : ]0-Har-!990 EVt.^85 Jcait: l5-Jun-|99O ( 01 I 01 I 0| I ])| I 01 I 01 I 0| Figure 4: Event display showing track fitting through Vertex Detector, Inner Detector ;HH1 innermost section of TPC; 1990 data 223 Group of Elementary Particles Experimental Physics 1. ZEUS Experiment tit HERA — Investigation of ep Interactions. J. CHWASTOWSKI, A. DWURAŹNY, A. ESKREYS, B. NIZIOL, K. PIOTRZKOWSKI, M. ZACHARA, L. ZAWIEJSKI The Cracow group of physicists and engineers participates in this experiment since its approval in 1985. Their responsibility within the ZEUS collaboration has been the design and construction of the luminosity monitor. In November 1991 the first stage of construction has been finished and first measurements of the HERA collider luminosity have been performed. The concept of the measurement is based on detection of bremsstrahlung events ep —+ ep~f. Their rate after corrections for detector inefficienceo and biases measures directly the lu- minosity. An example of such measurement is ohown in Fig.l where the bremsstrahlung rate Rbr [Hz] 20 - 10 - 40 Time [min] e-gas ep + e-gas Figure 1: Bremsstrahlung rate as a function of time, as a function of thne is displayed for one of the HERA runs. The sudden increase 224 in the rate occurred when electrons and protons collided. This increase corresponds to the luminosity value of (7 ± 2) • lO^cro"2*-1 . 2. Experiment NA22 at CERN SPS Investigation of High Energy Hadron - Proton/Nuclei Interactions. A. ESKREYŚ, K. OLKIEWICZ Since over 10 years the Cracow group is participating in the EHS - NA22 experiment which has been performed at the CERN SPS . The EHS (European Hybrid Spectrometer) has been used to investigate the interactions of the 250 GeV positively charged particles with hydroli and nuclear targets. During 1991 the Cracow group has been active in the analysis of the hadron - nuclei data. The detailed analysis of the rapidity and transverse momentum distributions was performed. The results prove that the controversial problem of whether the interaction with a nucleus can be understood as a convolution of interactions with the individual imcleons is still open. In particular the transverse momentum studies Teveal clear differ- ences between elementary and nuclear collisions (excess of large p? particles in nuclear collisions, different multiplicity dependence of average pj)} which are difficult to under- stand within such a picture. 3. Experiment NA35 at CERN SPS ; Interactions of relativiBtic nuclei. J. BARTKE, E. GLADYSZ-DZIADUS, M. KOWALSKI, P. STEFAŃSKT The aim of NA35 experiment is to study interactions of relativistic nuclei from the CEB.N SPS with stationary targets in a search for a phase transition to the Quark-Gluon Plasma. It is performed by the collaboration of European and US laboratories1, using a full 6olid angle hadron spectrometer with a 2m streamer chamber as the main tracking detector. Since the beginning of the experiment in 1987, data on various targets have been accu- mulated with 16O and Z2S beams at energies of 60 and 200 GeV/nucleon under various trigger conditions. In 1991 our contribution was mainly the analysis of multiplicity fluc- tuations in rapidity windows and a otudy of fractal characteristics of events. We also participated in a run at CERN when more data with 325 beam have been recorded, also using new detectors : a prototype time projection chamber (TPC) and a ring-imaging Cerenkov counter (RICH). In September 19dl our proposal to study Pb + Pb interactions at 160 GeV/nucleon with a modified detector was approved, meaning the extension of these studies for another few years as a Pb beam is planned for 1994. Athens, Bari, Berkeley, CERN, Cracow, Darmstadt, Frankfurt a/M., Freiburg, Marburg, Munich, Seattle, Warsaw, Zagreb. 225 E685 Experiment; Deep Inelastic Muon-Nucleon Scattering. XTESKREYS, J. FIGIEL, P. MALECKI,~K. OLKIEWICZ, B. PAWTIK:, P. STOPA. The E665 experiment is devoted to the Btudy of deep inelastic muon - uucleon inter- actionB at 490 GeV/c muon momentum. It is performed by the collaboration of American and European high energy physics laboratories2 using the Tevatron accelerator of FNAL. The aim of the experiment is to investigate the Btrong interaction of quarks, in particular the nucleon structure and the quark fragmentation. In 1987/88 the data were taken with the detector consisting of the streamer chamber and the spectrometer using the H% , D% and Xe targets and a fi+ beam. The high energy beam and the acceptance of the trigger enabled to investigate the new kinematic region of 5 very small XBj (2 x 1O~ < XBj < 0.1) and high CMS energy (4 GeV < W < 32 GeV). By the end of 1991 the measurements of the streamer chamber films were completed (about 4000 pictures were measured in Cracow) and the reconstruction of full events (using the information from streamer chamber and spectrometer) was finished. Among the variety of physics topics which can be studied the first one was the quark fragmentation into hadrons [18]. The investigations of the nuclear shadowing in deep in- elastic scattering and the intranuclear cascading are well advanced. In the 1990/91 running period the new data were taken with the upgraded detector using the Pb , C , Ca , Di and Hi targets. sAigonne National lab., UC San Diego, Cracow, Fermilab, Freiburg, Harvard, UI Chicago, Maryland, MPI Munich, Seattle, Wuppettal, Yale. 226 HI EXPERIMENT AT HERA HI is one of the two experiments at HERA accelerator . It was prepared by the inter- national collaboration of the 28 scientific institutes a with participation of the Institute of Nuclear Physics at Cracow 2 3 The experimental program includes search new physics ouch as quark and lepton substructure, proton structure function measurements , jet and heavy quark physics. To acomplish these goals the detector was designed to fullfi.il the following requirements • high degree of hermeticitytin order to investigate phenomena involving energetic neutrinos • excellent energy flow measurements for the inclusive measurements of neutral and charged current interactions o fine granularity and absolute energy calibration for both electromagnetic and hadronic calorimeters e excellent electron identification « muon identification The detector arrangenment is shown in the figurę on the next page. We have: o central and forward tracking provided by the central jet-chamber (2) and forward tracker (3) • electromagnetic calorimeter utilizing Pb plates and liquid argon (LAr) in the central and forward region (4) and lead scintillator sandwich in the backward region (12) e hadron calorimeter (5) using liquid argon with stainless steel absorber plates • superconducting coil and its cryostat (6) outside the hadron calorimeter » surrounding all of the above a set of iron plates (10) to contain return flux; inter- leaved with plastic streamer tubes it acts as a tail-catcher for the hadron calorimeter and also as a muon filter and tracker. ŁAntwerpen Univ., Brussels Univ. libre and vrye, CEN Saclay, Davies Univ., DESY, Dortmund Univ., Ecole Polytechnique (Palaiscau), ETH (Zurich), Glasgow Univ., Hamburg Univ. (1. and 2. Institute), Institute of Nuclear Physics (Cr .cow), Institute of Physics (Prague), Institute of Experimental Physics (Kosice), Institut fiir HEP Zeuthcn, INFN Roma, Lancaster Univ., Liverpool Univ., Lund Univ., Manchester Univ., ITEP (Moscow), Lebedev Physics Institute (Moscow), MPI (Mxlnchen), LAL Orsay, P. & M. Curie Univ.(Paris), RWTH Achcn (1. and 3. Institute) , Rutherford Appleton Lab., Wuppertal Univ., Zurich Univ. 2Physicists: L. Gorlich, L.Hajduk, W.Krasny, S.Mikocki.J.Martyniak, G.Nowak, K.Rybicki, J.Turnau 3Engineers: E.Banaś,A.Cyz,J.Godlewski, W.Janczur, M.Lemler,J.Olszowska 227 HERA Experiment HI Bcam pipo and beam magnets Muon chambers E Strahlrohr und Strahlmogncte MyonKanuncrn rji Central tracking chambers Instrumented Iron (Iron slabs L=J Zemrale Spurcnkammcm 03 + streamer tube detectors) pri Forward tracking chambers and Transition radiators Instrvmcnticrtcs Eisan (Eiscnplatten + L—I VoiYfirtispurkiunmern unti QbcrgangsitraMungunodut Stremerrdhnn-Ottektoren) Electromagnetic Calorimeter (lead) Muon toroid tnapnet 0 Elektmmagnetitohes Kalorimetcr (B/m'JLiquid Argon Myon-To'oid-Msgnot FISstig Argon Hadronic Calorimeter {stainless MCC<) Worm electromagnetic calorimeter HI Hodroniscłies Kalorimetcr (Erlclsvihl) wirmcs eloktromagnoo'sches Kalorimetcr m Supertonductini) coil H .2 T) Plug calorimeter [Cu, Si) I-2J Suprotcitcndo Spulc (1,2 71 VonvartsKatorimcter Compensating magnet Concrete shielding Kompcnsationsniagwi 0 Bctonabsclu'rmung nn Helium cryogenics Liquid Arjon cryostat '—' Helium KSItcinlagc Flihsig Argon Kryostat Perspective view of the Hi detector 228 Physicist from Cracow took part in tests of the prototype of the LAr calorimeter for the backward area, forseen as an upgrade of the HI experiment. 9 Contributions to the general software developement have been made by physicists from Cracow in the following areas: « 2-D HI detector display10 • LAr calorimeter reconstruction program*1 • Super-fast LAr calorimeter reconstruction program for forth-level software trigger (farm) 12 On the physics side of its engagement in the HI experiment the Cracow group has defined two topics where it would like to contribute by conception and performance of event analysis: • proton structure function measurement in particular in the small-x region • study of the heavy quark production by foton-gluon fusion and determination of the gluon structure function. Members of the Cracow Group have been actively participating in the Radiative Cor- rections, Inclusive Electron and Heavy Quarks Working Groups. A method for the low energy electron identification based on the analysis of the calorimeter CERN test data and Hl-simulation6 was developed. Also, in collaboration with Theory Departments of IFJ and Jagellonian University methods for treatment of the radiative corrections and the appropriate Hi programs were developed. 13 The Hi Group is prepared to analyze DST's at Cracow VAX-6tation-cluster. Transfer of PAW N-tuples by net was already tested and at the time of data taking the group will have to its exclusive disposition about 4 Gbt disk space and sufficient amount of computer work-places to take care of several PhD's and diploma students. 9W.Braunschweig et al.(L.Hajduk), Expression of Interest for a New Inner Backward Calorimeter in LAr Technique !0J.Martyniak contribution to EVLOOK MANUAL uL.G6rlich, H.P.Wellish, Documentation of the LAr Clustering HM2/91-204;H.Junget al. (L.GSrlich) Study of Software Compensation for Single Particles and Jets in the HI Calorimeter,Proceedings of the XXV International Conf. on HEP.Singapore 1990 12C.Bourdarios, M.Jafire, J.Turnau,Pattern Recognition Program for LAr Calorimeter,H 1-00/89-114 13W.Krasny ct al.,Semilocal Evolution of Singlet Structure Function for GLAP and GLR Equa- tion.DESY 91-073; W.Krasny et al., Determination of the Longnitudinnl Structure Function at HERA form RAdiative Events DESY 91-117; W.Krasny et al. The Monte Carlo Program LESKO-F for Deep Inelastic e^p —> e±X Scattering at HERA Including QED Bremsatrahlung from the Lepton Line, DESY 91-031 229 o muon detection provided by three layers of muon chambers (9) in the central and forward region complemented by a forward muon spectrometer consisting of mag- netized iron toroid and four layers of drift chambers (9). o plug calorimeter to detect small angle hadronic energy (13) built as a copper silicon sandwich which closes the detector down to an angle of 0.7 degrees. » compensating magnet (7). The detector is already assembled in the beam position , tested with cosmics and ready for data talcing, which should start at the and of April 1992. As it is the first presentation of the HI experiment we have made more general rewiew of the Cracow contribution, i.e. we do not restrict it to one year progress. The Cracow group contribution to the detector constuction were the boxes for analog calorimeter elec- tronics with complete cooling system and cabling. They wen; designed, tested, performed and finally installed at DESY by the team of physicists, engineers and technicians from Cracow. Our electronic and informatics engineers have made important contributions in the following areas: o. installation, setting up and customization of the Backward Electromagnetic Calorime- ter testing and calibration system.4 9 project of the prototype and production version of the Central Trigger Summing Card (the card responsible for the first level Hl-trigger decision) 5 » linking of the Calorimeter Data Aquisition System 0S9 crate with calorimeter VAX computer. This work includes the developement of the dedicated software for file transfer and software interface to calibration and monitoring of the LAr calorimeter6 a developement of various software utilities for IBM and Apollo Hl-software system and menagement of the HI routine simulations. 7 Physicists of the Cracow HI group have been collaborating with Orsay group in the area of the HI triggering systemfor several years. The collaboration is concentrated on the forward proportional chamber for the first level trigger and project of the second level, so called topological trigger (simulation of background rejection and signal acceptance).8 4J.Olszowska 5J.01szowska 6E.Banaś rA.Cya 8J.C.Bizot, S.Mikocki Proposal for a Topological Level 2 Ttigger,Hl-06/91-181;J.C.Bizot, G.Nowak, J.Turnau, Status of Simulation for a Topological Level 2 Trigger 230 First electron-proton collisions in the HERA accelerator Rale,Hz "Sight" time 18:57:00 19.10.1991 loona. 1800- 100 v 18 At 18M on 19 October 1991, first collisions of 12 GeV electrons with 480 GeV pro- tons were observed at the North Interaction point (see Fig.l) of the HERA accelerator. This was a milestone in a history of this unique machinej a history in which people from our institute also played an important role. They contributed about forty man-years of high-quality work on research, development, planning and construction of various critical aspects of the accelerator. It was beam optics (Edmund Bakewicz), cryogenics (Jacek Kiczek, Piotr Skóra and Tadeusz Waluga), electronics and steering (Jacek Kibinski, An- drzej Kotarba, Franciszek Koscielniak, Bogdan Madeyski and Andrzej Sobala), radiation protection (Dominik Dworak and Jan Zazula), radiofrequency ^Józef Baran, Jerzy Ko- recki and Jerzy Starzewski) as well as vacuum (Henryk Doruch and Bronisław Wojniak). Their work was highly appreciated by the DESY directorate and the success of the HERA accelerator is also their success. Now it is the turn of physicists from II-l and ZEUS collaborations to exploit the unique opportunity created by the successful commissioning of the HERA machine and to investigate the deep structure of quarks. 231 Measurement of the Mass and Width of the Charmed Meson D*+(2010) Amsterdam-Bristol-CERN-Cracow ] -Munich-Rutherford-Valencia Collaboration The vector charmed meson J9"+(2010) decays via strong interactions but its width is dramatically reduced by very 6mall phase space. The tightest upper limit of 1.1 Me V (90% CL) was published several years ago by the High-Resolution Spectrometer collaboration. We studied the reaction ir~Cu —> D"+ -f anything with a subsequent cascade decay D'+ —> D°ir+, D° —» K~n+ or D° -+ K~TT+IT' K . Since T(D°) & 0.4 ps we could observe D° decays in a very-high-resolution silicon vertex detector. A large-acceptance spectrometer allowed hadron identification in a wide mo- mentum range as well as high-accuracy measurement of effective mass. We have obtained a very clean signal of 127 events on a background of 17 events in the mass difference Am = m(D"+) - m(Z)°)-see Fig. 1. • i .i 'HI •n(0") ".(O1) (Ui Figure 1: Experimental distribution of Am = m(D"+) - m(Du) An extensive study of our experimental resolution was performed using decays of strange and charmed particles observed with high statistics in our vertex detector. This enabled us to check our mass error calculation for individual events. An empirical correc- tion factor was found to be equal to 1.03 ± 0.02. deluding A.Bożek, L.Górlich, Z.Hajduk, H.Palka, K.Rybicki and M.Witek 232 Parametrizing the Am distribution by the relativistic P-wave Breit-Wigner and ueing the maximum-likelihood formula, we have determined the following parameters of the £"+(2010): « Am = (145.39 ± 0.06 ± 0.03) MeV in good consistency with the world average of (145.44 ± 0.06) MeV • T(I>-+) < 68 keV (la) or T{D"+) < 131 keV (90% CL) The last number can be changed by ±7 keV due to error in background calculation and by ±3 keV due to error of the above empirical factor. Thus we have reduced an upper limit of F(D"+) by the order of magnitude. The phenomenological predictions range from 20 keV to 90 keV. 233 11 - The Crystal Ball Collaboration at DQRIS-II Because the Crystal Ball Collaboration at DORIS-II had finished its activity in 1991, this status report is both the first and the last one. That is why we looked back and gave a somewhat historical view. The Crystal Ball detector was operated in 1978-1981 at SPEAR e+e~ storage ring, then it was moved to the upgraded DORIS-II storage ring which reached the energies of the T resonances, i.e. about 10 GeV center of mass energy. The data have been taken in 1982-1986 with an integrated luminosity of 254 pb"1. The Crystal Ball is a highly specialized detector to measure the energy and direction of electromagnetically interacting particles over a very large solid angle in the Nal(Tl) calorimeter. Detectors with better performance became available only in 1989 (CLEO-II at CESR and Crystal Barrel at LEAR), The Crystal Ball experiment was operated by 14 institutions1 and about 120 physicists with a little help of technical staff2. The data analysis has been finished in 1991. The physics topics investigated by the Crystal Ball at DORIS-II can be classified as follows o quarkonium spectroscopy o QCD • weak decays of B and D mesons as well as r leptons e hadron spectroscopy in 77 interactions. The main results have been e the measurement of ree and J3MA) for T(1S) and T(2S) resonances » the measurement of 7-transitions to the xt-states and determination of spin for %b states • the measurement of 234 There was also a considerable shift load . In addition, we took part in the calibra- tion of time-of-fligh system, luminosity, detektor-checka by software and management of production tapes at DESY . One diploma thesis (T. Skwarnicki), three Ph.D. theses (Z. Jakubowski, T. Lesiak, T. Skwarnicki) and one habilitation thesis (B. Muryn) based on the tiata. had been writ- ten . Summer students (J. Martyniak, I. Sakrejda, M. Wolter) also contributed to the experiment. As it was stressed by prof, J. K. Bienlein, the co-spokesman of Crystal Ball Collabo- ration, we all shared fun, worries and excitement in physics for these almost 10 years of collaboration. 1V5 Investigation of Hadron-Nucleus Interactions. /"* Fermilab Experiment E—730: E~—Nucleus Interactions in Emulsion at 350 GeV. M.Szarska, H.Wilczyński, W.Woltcr and K.Woźniak The experimental data on multiplicities and angular distributions of heavy ionizing and shower particles in inelastic interactions of 350 GeV £~ hyperons with emulsion nuclei were investigated. The data were compared with the results of proton and pion interactions in emulsion. The interaction mean free path for inelastic S~—emulsion interactions was found to be A = (38.4 ± 1.5) cm which corresponds to cross-section a = (330 ± 13) mb. The mean multiplicities of produced particles and heavy ionizing particles emitted from the struck nucleus were found to be equal 15.2 ±0.4 and 6.9 ±0.2 respectively [1]. The global characteristics of £~ interactions are consistent with the assumption of incoherent superposition of intranuclear projectile-nucleon collisions. The observed small differences in parameters describing IT, p, and S" interactions can be explained by their different cross-sections on nucleon, 1. M. Szarska et. al., to be published in Phys. Rev. Ą *.''*> Fcrmilab Experiment E—687: Multiparticle production in Pion-Nucleus Interactions at 525 GeV. Kraków—Louisiana—Moscow—Tashkent Collaboration Krakow Group: A. Dąbrowska, R. Holviiski, M.Szarska, W.Wolter and K.Woźniak Until now we have done three emulsion exposures to negative pion beams at Fermilab, at 200, 300 GeV [1,2] and 525 GeV respectively. Our recent experiment E—667 is a continuation of our previous studies at the highest possible negative pion beam energy. We have already analysed more than one thousand interactions. Pre'lminary results of some parameters describing the interactions have been obtained, e.g. the average number of produced particles in ix—emulsion interactions at 525 GeV was found to be (n,) = 15.17 ± 0.25. The comparison of the presently investigated data with those obtained earlier at lower energies will allow us to analyse the characteristics of TT"-nucleus interactions as a function of the primary energy. 1. J. Babecki et. al., Acta Phys. Pol. B0, 495 (1978) 2. R. Holyński et. al., Acta Phys. Pol. B16, 323 (1985) 236 Investigation of Cosmic Rnyti at balloon and sea level altitudes The JACEE Experiment Kraków JACEE Group: ILHolynski, A.Jurak, B.Wikzyńska, H.Wilczyński, W.Wolter and B.Wosiek The JACEE experiment, was conceived for the dunl purpose of studying the physics of high energy nucleus-nucleus collisions and for investigating the composition and energy spectra of primary cosmic rays at energies extending up to about 1015 cV, Since 1.979 ten balloon flights with large-area emulsion chambers were launched. These include two flights from Australia to South America (sec Fig.l). The basic design of the detector shown in Fig.2 was approximately the same for all the JACEE flights, having a target section with ~ 0.2 proton interaction mean free path and the emulsion calorimeter with vertical depth ~ 7 radiation lengths. The updated differential energy spectra [1,2] of protons, helium, (C—0) and Fe [Z > 25) arc shown in Fig.3. From this figure the following conclusions can be drawn: l.The energy spectrum of primary protons fitted by a single power law holds up to 80 TcV. The indication of deficiency of proton intensivity beyond 80 TcV was observed. 2.The overabundance of helium in comparison with the lower energy data continucb up to 100 TeV/nucleon. 3.The intensities of heavy elements (C to Fe) above 1 TeV/nucleon are consistent, within statistical errors, with the new extrapolation from lower energy data of the Spacclab2. JACEE BALLOON FLIGHTS m \ PRIMARY y TARGET •SPACER CALORIMETER Australia to South America Fig-1 Fig.2 237 10 IOJ o 10' 10' o PROTONS • HELIUM 10 «c-o «No-S(»O.2S) -.1 I. 10' 10 104 10* (Gi>V/imcleon) Fig.3 l.K.Asnlcimori ct.nl., Proc. 22nd International CoBtnic Ray Conf.-rence, Dublin, Urlnii.1, Vol. 2, 57 (1901) 2.K.Armkimori et.n.1., Proc. 22nd International Cosmic Ray Conference, Dublin, Ireland, Vol. 2, 07 (1991) I The GRAND Experiment Kraków GRAND Group A. Trzupck and S.M. Mikocki As a result of discoveries of ultra-high energy astrophysical point sources, new exper- imental methods in the construction of extensive air sliower (EAS) arrays have been, developed to obtain improved angular resolution. Project GRAND developed at the University of Notre Dame is an EAS array which uses proportional wire chambers to geometrically measure secondary cosmic ray angles. Actually the test of the particle identification method for new setup of a station in the GRAND was done [1], This method uses position sensitive proportional wire chamber to measure the effect of a thin steel absorber on the trajectories of individual shower particles. The test utilizes actual cosmic ray secondaries which are preselected as muons or electrons. It was found that the misidentification of muons by electrons or electrons by muons is only a few percent. Moreover a new, hybrid Monte Carlo simulation was done to get angular dis- tributions of secondary electrons and muons in EAS initiated by 10, 100, 1000 and 10000 TeV gamma rays and protons [2,3]. This procedure allows fast, yet precise, calculations down to low secondary particle energies. In this new approach to simulation of EAS the dependence of angular distribution for different threshold energies and shower siza fluctuation as well as lateral distribu- tions nnalysis is possible. l.S.Mikocki ct. nl., Nuclear Instruments and Methods in PhyBics Research A302, (1901)368-375 2. A.Trzupck et.nl., J. Phys. G.: Nucl. Part. Phys. 17, (1991) L19-L26 3. S.Mikocki et. al., J. Phys. G.: Nucl. Part. Phys. 17, (J991) 1303-1315 238 Investigation of Rclntivistic Heavy Ion Interactions at the Highest /IS1 Accelerator Energies Krakow—Louisiana—Minnesota (KLM.) Collaboration Kraków KLM Group: A.Dąbrowska, R.Holyński, A.Jurak, A.Olszewski, M.Szarska, A.Trzupek, B.Wilczyńska, H.Wikzyński, W.Woltcr, B.Wosiek, nnd K.Woźniak The aim of the KLM Collaboration is to investigate heavy ion interactions in a broad range of primary energies and atomic mass of ion projectiles. Till now we have already exposed nuclear emulsion to oxygen, silicon and sulfur beams at AGS in Brookhaven at 15 GeV/nucleon and at SPS in CERN at 60 and 200 GeV/nucleon. The first results were published in [1,2,3}. The recent investigations carried on since 1991 are concerned to Oxygen and Sulfur interactions with emulsion nuclei at 200 GeV/nucleon (experiment CERN, EMU-07). The obtained results have been compared with those from proton-emulsion interactions nt the same primary energy. It was found [4,5,6] that the mean multiplicity N„ of produced particles in proton, Oxygen nnd Sulfur interactions in emulsion depends linearly on the mean number NCo\\ of intranuclear nucleon-nuclcon collisions. Morover, the same dependence holds when the inclusive data of Oxygen and Sulfur interactions is divided into subsamples characterized by different degree of centrality (see Pig.1). It means that the multiplicity JVff depends on JVcon, not on the projectile mass. The linear dependence between Nw and ./Vcoii, is in general valid over the entire range of Wc0]i considered. More detailed analysis performed on the pseudorapidity 77 distributions has shown that the linear dependence of JV„. on Nco\\ holds for each particular pseudorapidity interval. The pseudorapidity densities'in Oxygen and Sulfur interactions have been compared to the particle densities in proton-proton collision 350 300 30 E-?COG«V/nucleon 250 25 200 20 Z ' 150J fir a.,.- O-Em 100 10- • • • °O00 50-j 5 -1 I I I I I I.-L_l_ l_l_ 0 20 40 60 60 100 120 NrG1L -2 6 1} Fig.l Fig.2 239 (normalized particle density R = P^A-A/pi^p-p) a' the same primary energy. Figure 2 shows the parameter R as a function of pseudorapidity for both Oxygen and Sulfur interactions. In the pseudorapidity region most relevant to particle production (-2 < 17 < 6.5) the normalized particle density depends only weakly upon TJ and never exceeds the average value of Nco\\ [4,5,6]. This implies that no significant cascading occurB in nucleus-nucleus collision. We have also investigated the multiplicity and the angular distributions of heavy ionizing particles emitted from the target nucleus which due to the collision with the projectile becomes excited and fragments. The fact that the angular distributions are independent of the tj'pe of the projectile indicates that the mechanism of slow particle production is identical in all cases irrespective of the number of intranuclear nucleon-nucleon collisions. All of the results presented above strongly support the interaction models in which hadron-nucleus and nucleus-nucleus interactions are considered as an incoherent superposition of intranuclear nucleon-nucleon collisions. 1. L.M.Baibier et. al., Phys. Rev. Lett. 60, 405 (1988) 2. R.Hołyńslci et. al., Phya. Rev. Lett. 02, 733 (1989) 3. R-Holyński et. al., Phys. Rev. C40, 2449 (1989) 4. M.L.Cherry et. al., 22nd ICRC, Dublin, Contributed Papers Vol.4, (1991), 17 and Inst. of Nucl. Phys., Krakow, Rapoit Nr. 1566 IPH (1991) 5. M.L.Cherry et. a.1., 22nd ICRC, Dublin, Contributed Papers Vol.4, (1991), 13 and Inst. of N«cl. Phyi., Kraków, Report Nr. 1565 IPH (1991) 8. M.L.Cherry et. al., Vol. of Contributed Papers submitted to the QM'91 Conf. Paper E21- 240 Development of silicon strip detectors with VLSI readout electronics for future experiments of high energy physics S. GADOMSKI, P. JALOCHA, S. MOSZCZYŃSKI, M. TURALA, A. ZALEWSKA There are broad plans to use silicon strip detectors in present experiments at CERN and DESY accelerators, as well as in experiments at the future hadron colliders, the Large Hadron Collider (LHC) in Europe and Superconducting Super Collider (SSC) in US. The applications include high precision tracking and calorimetry. The Cracow group is involved in the upgrading of the DELPHI Microvertex detec- tor at LEP at CERN [1] and also in the preparatory work on a Silicon Tracker of the SDC collaboration (SSC) [2] and a Silicon Inner Tracker/Vertex of the EAGLE collab- oration (LHC) [3j. The group is involved in studying physics ca6es for these detectors, in the development of the general concepts and individual components of these detectors (mechanics, cooling, strip detectors, electronics), in the construction of prototypes and studying of their parameters. 1 Physics and detector simulation The LHC accelerator will operate at energies 2x8 TeV and at the luminosities up to L — 2 * lO3''cm~23~'. At such conditions the number of charged tracks in the central region of a detector will be around 400 - hence the "occupancy" of the detector has to be studied. It has been performed for a detector covering 4 units of rapidity (-2 < T/ < 2) and containing 105 — 106 strips/layer (lenght of 60mm and pitch of 50 um). As an input events geaerated on the CERN Cray computer have been used. The results show that in all cases, eg. for different radii and different position along the beam line, as well as for different values of magnetic field, the occupancy is not higher then 1%, which allows for safe operation (small pile-up) at highest luminosities [4]. o z §10 li i o /TS. — ^" \ M/B / — 1 ^ 1 III I i i u ml •*•! -10 12 10 1 IMPACT PARAMETER (mm) ACCEPTANCE KlR.l Fig-2 241 The other studies concerned the efficiency of B-jets tagging using a high precision tracking detector, by applying a cut on the impact parameter of produced tracks. The events have been generated on VAX computers using PYTHIA generator. The distri- bution of the impact parameters of tracks from B and non-B j~sts is shown in Fig. 1. Demanding a certain number of tracks exceeding a defined value of the impact parameter one can find the efficiency of isolation of B jets - it is presented in Fig. 2 for two CŁSCB of detectors with different geometries and consequently with different impact parameter resolution. 2 Silicon strip detectors Double sided silicon strip detectors have advantages of providing two coordinates from a single detector unit. So far only one experiment, APLEPH at LEP (CERN), is using such detectors, however the design is not optimal and a readout electronics is placed in the middle of its sensitive volume thus increasing the multiple scattering. The DELPHI experiment is planning to use 2-D Si strip detectors with a readout on external edges of Selector modules, thus avoiding the material in the central part of the Microvertex and expecting a. better impact parameter resolution. Double sided Si strip detectors have been designed at CERN and they have been produced by SI Oslo and VTT Helsinki companies. The separation between n-side strips is obtained by induced channel stops and the signals are transported to the readout edge using double-metal technology. The Cracow group has participated in testing of these detectors using a probe station (interstrip resistances and capa-citances), in laboratory tests with "Beta" and X-ray sources (signal-to-noise ratio, signal correlations) and in beam tests at CERN SPS (6patial accuracies). In Fig. 3 the dependance of the spatial accuracy from the track inclination is f.hown; such results are relevant for detectors with cylindrical geometries, such as the DELPHI Microvertex, where large angle tracks will be frequent [5]. 24 tr- — © n-side O p-sido 3 '6 o in 2 12 o hJ_U .JLJ__L_LJ_L_L ±J I I I I -10 0 10 20 30 Fig.3 242 3 VLSI electronics for Si strip detectors The use of silicon strip detectors in future experiments require electronics with very high speed, low noise and low power consumption, high radiation resistance. The Cracow group is involved in the development of such components: o a low noise monolithic preamplifiers have been developed; measurements Bhow noise level ENC = 165 e- + 12 e-/pF at integration time of 1 - 1.5 us and ENC = 430 e- + 70 e-/pF at peaking time of 45 ns [6], • a special signal processor ("deconvolutor") have been proposed and simulated on computers; such a solution allows to optimise a preamplifier and to restore fast timing with accuracy required at the LHC (15 ns) [7], • CMOS transistors produced in radiation hard technology have been irradiated and tested; the results show that such technology could be usefull for analog components of electronics which will be exposed to radiation doses up to 5 Mrad [8]. References [l] DELPHI microvertex detector, submitted to Nucl. Instr. Meth. [2] A. J. Weinstein et al. Subsystem R&D Progress Report for a Silicon Tracking System Raport SCIPP 91/28, Santa Cruz, Sept. 1991 [3] H. Borner et al. Development of High Resolution Si Strip Detectors for Experiments at High Luminosity at the LHc R&D Proposal, CERN/DRDC 91-11, March 1991 [4] S. Gadomski Presentation on the RD-20 Collaboration Meeting CERN, 13 Dec. 1991 [5] L. Hubbeling et al. Measurement of spatial resolution of a double-Bided AC-coupled microstrip detector Nuci. Instr. Meth. A310 (1991), 197 - 202 [6] P. Aspel et al. Raport CERN-PPE/91-154, submitted to Nucl. Instr. Meth. [7] S. Gadomski et al. Raport CERN-PPE/92-24, submitted to Nucl. Instr. Meth. [8] W. Dąbrowski et al. Noise measurements on radiation-hardened CMOS transistors presented at IEEE NS Symposium, Santa Fe, Nov. 1991 243 Development of mechanical structures and cooling for silicon tracking devices for future experiments of high energy physics J. GODLEWSKI, K. PAKOŃSKI, M. STODULSKI Problems: • developing of light, stable and precise mechanical structure with the micron accuracy and high resistance to vibrations, • developing of cooling system which gives acceptable temperature differences over the detector using as small mass of cooling agent as possible. For a detector with 2.3 milions channels and heat load 3 mW/channel the heat emitted equals to 7 kW The main fields of activity of the group in 1991 were following: • studies of mechanical structures, • studies of heat exchange and temperature distribution, • tests of gas cooling and gas flow distribution. The group uses the following facilities: 1. computers and software enabling CAD and CAM-calculations based on Finite Ele- ment Analysis (FEA): • AUTOCAD 11 on IBM 486, • AUTOCAD 10 on IBM 286 AT, • ANSYS Engineering Analysis System version 4.4 • MSC PAL2 Advanced Stress and Vibration Analysis version 3.5 • MSC CAL2 Thermal Analysis 2. a test stand (designed and built in 1991) for cooling tests enabling the following measurements: • temperature distribution on the surface of a wafer (infrared thermometer), • temperature of the flowing gas (resistance thermometers), • gas flow (orifice), e local gas velocity (thermoanemometer), 244 • electrical tension and current • pressure drop. All the measurements are recorded using a PC computer with PCLAB 812 card. In the frame of RD20 project (development of silicon strip detectors for LHC) the group was studying the problems concerning detector cooling and mechanical stability of a module of the detector. Two different models of a single detector were designed and built. To simulate the behavior of the models under heat load and dynamic pressure of cooling gas the MSC PAL2 and MSC CAL2 systems were used. Deflections, eigen values of vibration frequency and temperature distribution were investigated ( fig.l ). Both models were tested and the results of the tests were confronted with FEA simulation. The comparison between FEA calculations and the measurements results (fig.2 ) is promising and indicates that cooling the silicon detector with a helium gas flow seems to be feasible. For air flow velocity of 1 m/s and power dissipation of 2.5 mW/channel temperature difference between gas and chips for one metal layer model was following: • FEA result 24 K • measured value 18.5 K • For helium flow of 7 m/s which is equivalent to air flow of 1 m/s FEA result for temperature difference is 7.5 K. Also an idea of how a central silicon tracker detector may look like was outlined and presented. The proposed mechanical structure of the detector follows the "football" ge- ometry ( fig.3 ). The materials from the above mentioned tasks were presented by dr Iv.Pakonski during the meetings of RD20 group in Geneva on 3.06, 17.06 and 11.12.91. , Z M mpnv f: 3HSBH& UMD ZtfllK&CHON •K8888E- / ••• *. > %/ V -2.. t 245 KKA 1'i'sull (boundary condition from the Prnndll boundary luyer theory) nir, i/ FEA rcanH (boundary condilion taken from the measured thlcl FEA result (boundary condition tnken from tlic incosurcd thicknoss ol the lioundnry liiyer) helium, v=7m/s ©—&—©•—e—o—6—0— X i—i—,-..,_..,„., ,—t—*^ [irmil « 40 35 30 2.', 2n IS 10 S ID 15 SO RS 30 as 40 45 GAS PLOW fig. 2 Temperature difference between gas and chips for for one metal layer model i>owor cii - 2.5 T 1 fig.3 Side071 tracker detector "football " geometry 246 Development and Test of a Large Silicon Strip System for a Hadron Collider Beauty Trigger J.ELLET, S.ERHAN, P.KREUZER, D.LYNN, M.MEDINNIS, P.SGHLEIN, J.ZWEIZIG, G.ENGELMANW, O.KLINGSHEIM, K.LEY, M.PRICE, A.RUDGE, H.WAHL, P.WEILHAMMER, G.BORREANI, W.HOFFMANN, B.WILKENS, M.CALVETTI, M.PONTURO, Y.GUZ, Y.IVANUSCHENKOV, C.BiiNO, S.PALESTINI, L.PESANDO, R.HARR, P.KARCHIN, A.CZERMAK [INP CRACOV] Large aperture forward spectrometers with planar geometry perpendicular to the beam line are the natural detectors to accomodate the expected forward peaking of Beauty particle production at high energy hadron colliders. Such a silicon system was built and run at the CERN SPS Collider, Background-free events were seen with the vacuum/RF window of the silicon system 1.5 mm from the circulaiting beams. Triggering and Readout System Control signals for operation of the SVX chips were generated by the SRS (SVX Readout Sequqencer)[l] CAMAC module. This module contains an AMD2910 sequencer and 12kbytes oł program memory which may be downloaded from the host computer. The instruction length was fixed to 6 bytes with 2 bytes reserved for AMD2910 op-code and 4 bytes for bit patterns which are output via a front panel connector to the SVX data and control lines. The SRS control signals were corverted to differential levels and sent over a 50m flat twisted pair cable to the interaction region, where they were converted to single-ended TTL signals. The single-ended control signals were then bussed over two fiat cables to twelve Plug-In-Driver (PID) printed circuit boards which were mounted on the exteriors of the upper and lower pot mechanisms. This signal path, for one detector half-plane is indicated in Fig. 1. The detector readout was triggered by a coincidence of two scintillation counters, which detected particles produced at polar angles between 0.027 and 0.11 rad. The SRS was synchronized with the beam crossing by means of a signal from a directional coupler which sensed the beam passage. When live, the SRS generated a double ccrrelated sample-and- hold sequence for every beam bunch crossing (3.8usec). The CERN-designed SIROCCO II[2] module was used for analog to digital conversion. This module features optional hit sparsification as well as common mode and pedestal substraction. It contains a 10-bit flash ADC, and internal memory to store pedestals and pedestal-subs uracted pulse heights for up to 2048 channels. Twenty four of these modules were used. Readout to the host computer (MicroVAX II) was implemented using standard CA- MAC and ROMULUS/REMUS[3] modules. Silicon hit data together with pulse-height, pulse arrival time and sealer information from the scintillators were written to 8 mm tape cassettes using Exabyte tape drives. In readout sparsification mode, the SIROCCO threshold was 6et at three times the 247 average r.m.s. noise found in two daisy-chained detectors for each SIROCCO II. Channels passing the threshold were written to tape. In order to monitor pedestal stability and common mode noise, 21 additional "monitor" channels were always read oui. The event size waB typically 9 kbytes and the acquisition rate was approximately 35 Hz. Fig. 1. Schematic of readout and control paths for one detector half-plane. Control signals originate in SRS, travel via flat cable to the intersection region where they are fanned out to each of 12 PID boards. After shaping, the PID boards relay the signals to the readout hybrids via a vacuum feed-through board and short lengths of Kapton cable. SVX- D analog output follows the same route from hybrids to PID boards, where x- and y-view outputs are multiplexed, shaped, and sent to the counting room on shielded twisted-pair cables where digitization is accomplished by SIROCCO modules. References [1] F.Kirsten and C.Haber, IEEE Trans. Nucl. Sci. 37 (1990) 288. Automation and Communications, Canterbury Sept. 1978, IERE:London (1978) 309. [2] A.Lang and J.P.Vanuxem, SIROCCO II, A Silicon Strip Read-out CAMAC Con- troller with Flash ADC Input, CERN, EP-Electronics Note 90-01 (April 1990). [3] P.J.Ponting, A Guide to the Romulus/Remus DAQ Systems, CERN-EP-EL Note 80-01 (CAMAC Note 310), (1980). 248 .'£.4- Noise Measurements on Radiation-Hardened CMOS Transistors W.DĄBROWSKI, D.KIDWELL, W.A.ROWE, H.F.W.SADROZINSKI, E.N.SPENCER, H.SPIELER, P.TENENBAUM, M.TURALA, M.WILDER, M.KAJETANOWICZ [INP CRA- COW] NMOS and PMOS t-ansistors with width varying from 75um to 1332um and length of 1.2, 2.2 and 3.2 urn produced by UTMC[1] were subject to total Co-60 doses of up to 5MRad. Radiation effects on the transconductance and on both the white and frequency- dependent noise were measured. The motivation of this work was design of a low-power, low-noise frontend for a silicon microstrip tracking device for the SSC. Fig. 1 shows the scaled transconductance gm/lDS vs the current density IDS/W pre-rad and after a dose of 5MRad. The scaled curve is universal for for constant length L. I 0'' 10' Idi/W (A/m] Fig. 1, Transconductance as the function of the current density. When changing the length of the transistors, transconductance decreases appreciably in the transition region between depletion and inversion where noise xneasuremeiato were done as indicated by the arrows. The data indicate that ths transconductance of PMOS transistors is insensitive to high doseB, showing only a few percent decrease with a dose of 5MRad, while the one of NMOS transistors show decreases of about 20%, independent 249 of current density and geometry. The noise spectra for the NMOS and four PMOS transistors were taken for pre-rad and after 5MRad do&e. Ths square root of the power spectrum ia shown in ^ig.2 ae the function of frequency. Measurements were done using PMOS and NMOS transistors of the same geometry W/L = 1332/1.2 and at the same current density IDS/W = 0.1. While the NMOS noise increases during irradiation by a factor 2 over the whole spectrum, the PMOS noise increases by 1.7 at 10kHz and by 1.2 at 6MHz. > ; rfr : -I rrtTt-'—i rT+Pn" * 'w**"*- Ijrfin—f~t-!-rhr;r- . ««»i«u.~ ! Fig. 2 . Comparison of the spec- '71 I, T~1—lT'~r* " «*»•««*>• tral noise voltage Vn for NMOS and PMOS transistors of identical geom- etry {W/L = 1332/1.2), at the same current density 1DS/W = 0.1 pre- and post-rad. References [1] United Technologies Microelectronic Center, 1575 Garden of the Gods , Colorado Springs, CO 80907 250 SECOND-LEVEL TRIGGERING FOR LHC EXPERIMENTS I 1*. MlAJ,AS, K. CliTNAR, J. CirWASTOWSKl, S. J AGIICLSK!, P. MALKCKI AND A. SOHAI.A Detector systems for future experiments at Large Madron Collider must tolerate un- precedented frequency of events. First stages of signal processing electronics of various detector components will collect megabytes of data at rates corresponding to 66.7 MHz of bunch crossing frequency. Selection of interesting events from the background of "trivial" hadronic interactions becomes an extraordinary problem as these interesting phenomena represent many orders of magnitude smaller cross sections than all proton-proton colli- sions. A great part of the data reduction task has to be done in the real time. Often, one splits that task, somewhat arbitrarily, on several levels. The first-level, closely connected with the front-end electronics, pulse shaping, preamplification, discrimination etc., is assumed to be responsible for the first three orders of magnitude of the data reduction. Detector components responsible for the second-level selection tasks, the second-level trigger stage, will be exposed to the input s'ream of events at rate of 100kHz. At this stage, decision making requires digital processing of high complexity. Several aspects of events preselection are studied by various groups, working in CERN series of Research and Development (R&D) projects for LHC. In particular, RDl 1 [Embedded Architectures for Second-level Triggering in LHC Experiments (EAST) - CERN/DRDC/90-46 October 1990] has been created "for exploring one of the critical aspects of the implementation of detector selectivity, that of embedding 'intelligent' de- vices for triggering". Work of this R&D project, in which a group of people from our Institute takes part, is coupled to several of the proposed detector subsystems. In the following, we concentrate on triggering aspects associated with the Transition Radiation Detector (TRD). Integrated transition radiation detector and charged particle tracker, one of options for an inner tracking system for LHC, is studied by RD6 [CERN/DRDC/91-47 22 Oct.1991]. Our Institute takes also part in this project. Detector configuration is under detailed studies. For our purposes we consider the cylindrical setup which consists of several hundred planes distributed uniformly along the beam axis, each in the shape of a circle with an inner radius of 50 cm and an outer one of 100 cm. Each plane contains 600 radially mounted thin-walled proportional straw tubes, 4 mm in diameter. Tubes are embedded in the polyethylene foam radiator, Spacing between planes was taken to be 8 mm. The TRD is located in the solenoidal 2 Tesla magnetic field and surrounded by the fine-grain calorimeter. The first-level trigger information in such an experimental setup can be obtained from the calorimeter, e.g., as a cell number, addressing a cluster of accumulated energy. The second-level trigger task is to associate the calorimeter information with the fully 251 digitized data from Till) and decide whether any fast electron track caused this energy accumulation. It includes the selection of the region of interest in which the reconstruction an identification of tracks has to be performed. The experimental setup described above was used in the computer simulation pro- grams which generated data for tests of various processor architectures, possible candi- dates for system components. Events of p-p interactions at 16 TeV cms energy have been generated by PYTHIA/JETSET programs and used as the physical input. Input data for a single bunch crossing are formed as pileup of many such events (e.g., number taken from the normal distribution with the average of 20) to reflect the high luminosity mode of operation of the collider. In addition a high p<, high energy "trigger" charged particle (electron or pion) is appended to the input data. Charged particles are processed through the detector structure and all hits in straw tubes are recorded. Also, simplified TR effect is taken into an account, allowing for the crude distinction between high energy electrons and pions. In practice trigger particle is processed first and the corresponding impact cell in the calorimeter is found for it. That cell and the region of the main vertex of collisions allow to cut out a wedge shape volume, the region of interest. Now, only particles in this region require further processing. These functions reconstruct an action of the first level trigger and simulate some hypothetical routing device, which is capable to significantly reduce the data for processing on the second level of the event preselection. Output of the chain of the relatively plain programs, coded in C is in the form of the image of hit patterns in "coordinates" : straw number vs. plane number, which are close to the Z $ plane, where Z is the axis along the beam and $ is the azimuthal angle. This output serves as a benchmark material for testing track finding and identifying algorithms as well as for testing their implementations on available parallel processors. Our simple and "portable" simulation programs are easily adapted to serve various technical information on straw occupancy, number of hits per track etc., for various in- put and detector conditions. There are, however, serious limitations. Detailed detector simulation and optimization taking into an account e.g., physical processes like gamma conversions, electromagnetic and hadronic interactions in detector materials or details of detector construction is developed in parallel, using the machinery of the GEANT program. 252 Benchmarking with Data from Transition Radiation Detector using Parallel Computer — MasPar ANDR/KJ SOBALA The purpose of the benchmarks was to compare the feasibility of different hardware implementations of a track finding algorithm of a trigger particle, based on data from the Transition Radiation Detector)] ]. This "second-level" trigger is expected to recognize electron-like tracks in the TRD, distinguished by their pulse height distribution. The search is restricted to a window which has been defined by a preceding "first-level" trigger in an electromagnetic calorimeter. The agreed working hypothesis concerning the detector constniction|2] has been used. The single trigger particles together with the minimum bias events in realistic pileup situation have been simulated. Only the forward endcup part (Z > o) of the detector was considered. Da'a sets have been generated in various formats of which only the image files are used for benchmarking. The window of interest is chosen to represent the crude selection of data in a router, device reducing the data volume by a factor of about 13 (19200 channels out of 35 (modules) * 12 (planes) * 600 (straws) = 252 000 channels). The target algorithm for the ber. ;hmarking was unambiguously formulated in high- level language (in C). The principle of the algorithm is to find whether at least one electron-like track, which ends in tli3 calorimeter cell and is fully contained in the search window, can be identified (using the pulse height information). One of implementations of the TRD algorithm has been done on the parallel computer - MASPAR[3]. This is a massively parallel SIMD (Single Instruction Multiple Data) machine with the following key characteristics: - scaleable architecture in terms of: • the number of processing elements, • system memory, • system communication with high bandwidth, - RISC-like instruction set for each processing element and - an architectural design amenable to a VLSI implementation. The implementation of the TRD algorithm has been wiitten in MPL (MasPar Lan- guage). MPL is based on K&R C language with several extensions involving plural data types and operators. The final conclusions from MasPar implementation of the TRD algorithm are: 253 MasPar, a general purpose massively parallel computer, an excellent device for many applications, docs not seem to be suitable for the task assigned to "second-level" trigger. The requested execution time of 10 mi- croseconds (a consequence of the 100 kHz input data rate) can be satisiied by (impractical) buffering data from many events (400) and processing them all in 4 miliseconds. Also, there is no clear solution for the input/output problems. Presently, MasPar producer does not offer any I/O interface satisfying our bandwitb requirements. In particular the announced HEPPI option is not yet ready. In addition, the cost of MasPar solution as the "second-level" trigger processing unit is relatively high for an embedded computing architecture. References [1) CERN/EAST note 92-10 Benchmarking with Data from the Tran- sition Radiation Detector - Implementation on MASPAR Computer (A.Sobala). [2| RD-6 Status Report, CERN/DRDC/91-47, 22 Oct 1991. [3) MasPar system overview, PN 9300-0300. |4] MPL reference manual, PN 9302-0000. MPL user guide, PN 9302-0100. 254 THEORY GROUP KACPER ZAJ.EWSKI A central problem of present particle physics is to look for deviations from the predictions of the so-called standard model. Even with the highest energies, given by the most powerful available accelerators these deviations are likely to be small quantitative results rather than striking qualitative features of the data, Therefore, it is very important to know what the standard model really predicts for the experiments being done. The precision of these predictions should be at least as good as the experimental precision and this requirement is becoming more and more difficult to meet. The theoretical "product" is usually in the form of Monte Carlo programs able to generate the distributions predicted by the standard model. At present the programs created by Jadach, Was and collaborators are among the best. They are used by all the four experiments at the world most powerful e+e" collider LEP in CERN and they will be used at the world most powerful e ••- p collider HERA at DESY when it starts taking data. As experiments progress, however, new problems requiring modifications and extensions of the programs appear. This makes it necessary to solve new theoretical and numerical problems, because each generation of programs is at the limit of what can be done at the time when it :,s produced. The year 1991 has been another fruitful year in this important branch of research. Tn particular, predictions of the standard model asymmetry for the muon pairs produced at LEP have been completed [1] and the extension of the approach of Yenni, Frautschi and Siiura used for this kind of problems has been summarized [2], also analytic approximate distributions for Bhabha scattering have been found [3]. For HERA the interesting quan- tity is the proton structure function. Methods for evaluating this structure function in the framework of the standard model have been given [4], [5]. A very recent result [6] suggests that the expansion proposed in [5] can lead to a formally exact solution for the structure function. This result could be of great interest. References 1. S. Jadach, B.F.L. Ward and Z. Was, Phys. Letters B257(1991)213. 2. S. Jadach and B.F.L. Ward, Acta Phys. Pol. B22(1991)229. 3. S. Jadach, E. Richter-Was, B.F.L. Ward and Z. Was, Phys. Letters B253(1991)469. 4. M. Skrzypek and S. Jadach, Z. Phys. C49(1991)557. 5. S. Jadach, M. Skrzypek and B.F.L. Ward, Phys Letters B257(1991)173. 6. M. Jeżabek, "A perturbative solution to Gribov - Lipatov equation" Karts-ruhe Uni- versity preprint TTP91 - 10 (1991). List of publications in 1991 Theory groupt 1. A. Czarnetzki, M. Jeżabek and J. H. Kuhn: Lepton spectra from polarized top quarks. Nuci. Phys. B351 (1991) 70 2. A. Bialas and K. Zalewski: Vacuum insertion method from chiral N -* oo approach for the AS = 1 effective Hamiltonian. Acta Phys. Pol. B22 (1991) 319 3. K. Zalewski: Isgur Wise symmetry and heavy hadron wave functions. Phys. Lett. B264 (1991) 438 4. Z. Burda, J. Wosiek and K. Zalewski: Effective scaling of intermittency momentB in the 2nt/ Tsing model. Phys. Lett. B266 (1991) 439 5. S. Jadach et al (Z. Wąs): Analytical 0(o-t for Bhabha scattering at low angles. Phys. Lett. B253 (1691) 469 6. S. Jadach, B. F. L. Ward and Z. Wąs: Complete standard model pr< inuon forward backward asymmetry at LEP. Phys. Lett. B257 (1991? 7. 3. Jadach et al (Z. Wąs): High order QED corrections to Bhabha scattering at low angles. Phys. Lett. B260 (1991) 438 8. S. Jadach et al (Z. Wąs): QED multiphoton corrections to Bhabha scattering at low angles. Phys. Lett. B268 (1991) 253 9. S. Jadach Z. Wąs: TAVOLA-A library ofM.C. programs to simulate tau decays. Comp.Phys.Comm. 64 (1991) 275 Phys. Rev. D44 (1991) 2669 10. S. Jadach, Z. Wąs: KORALB version 2.1, and upgrade with TAVOLA. Comp. Phys. Comm. 64 (1991) 267 11. S. Jadach, B. F. L. Ward, Z. Wąs: Monte Carlo program KORALZ version 3.8. Comp. Phys. Comm. 86 (1991) 276 T.Cgroup: 12. P. Marage et al (T. Coghen, W. Burkot): Coherent production of A\ meaono and (p«"~) systems by antineuirinoa on neon. Z. Phys. C49 (1991) 385 13. A. E. Asraiyaa 256 14. R. Verluyten et al (T. Coghen): Study of factorial moments in neutrino charged current interactions on neon and deuterium. Phys. Lett. B2G0 (1991) 456 15. V. V. Aivazyan et al (K. Olkiewicz): Factorial correlations from n rp and K^p collisions at 250 GeV/c. Phys. Lett. B258 (1991) 487 + 16. N. M. Agababyan et al (K. Olkicwicz): Low pt intermittency in ir*p and K p collisions at 250 GeV/c. Phys. Lett. B261 (1991) 456 17. M. R. Adams, et al(A. Eskreys, J. Figiel,P. Malecki, B. Pawlik, P. Stopa): Distributions of charged hadrons observed in deep-inelastic muon-deuterium scattering at 490 GeV/c. Phys. Lett. B272 (1991) 163 18. N. M. Agababyan et al (K. Olkiewicz): Triple Regge analysis of inclusive A production in K+p and n+p interactions at 250 GeV/c. Z. PhyB. C49 (1991) 235 19. I. V. Ajinenko (K. Olkiewicz): Collective characteristics of hadron system produced in beam fragmentation of ir+p collisions at. 250 GeV/c. Z. Phys. C49 (1991) 367 20. M. R. Atayan et al (K. Olkiewicz): A study of double pomeron exchange in K^p and x+p interaction at 250 GeV/c. Z. Phys. C50 (1991) 353 21. N. M. Agababyan et al (A. Eskreys, K. Olkiewicz): Rapidity and transverse momentum structure in ir+ and K+ collisions with Al and Au nuclei at 250 GeV/c. Z. Phys. C50 (1991) 361 22. I. Der%do et al (P. Malecki): Prodution of neutral strange particle in p - Au,p - Xe and p - Xc collisions at 200 GeV/c. Z. Phys. C50 (1991) 31 23. F. Botterweck et al (A. Eskreys, K. Olkiewicz): Factorial moments and correlations in meson-nucleus interactions at 250 GeV/c. Z. Phys. C51 (1991) 37 24. J. Bachler et al (J. Bartke, E. Gladysz, M. Kowalski): Charged particle multiplicities in nuclear collisions at 200 GcV/Nucleon. Z. Phys. C51 (1991) 157 25. V. V. Aivazyan (K. Olkiewicz): Rapidity correlations in 7rj'p, K+p and pp interactions at 250 GeV/c. Z. Phys. C51 (1991) 167 2(5. F. Botterweck et al (A. Eskreys, K. Olkiewicz): Direct soft photon production in K+p and n+p interactions at 250 GeV/c. Z. Phys. CB1 (1991) 541 27. N. M. Agababyan et al (K. OLkiewicz): Deuteron production in collisions of 250 GeV/c JT1 and K+ mesons with Al and Au nuclei. Z. Phys. C52 (1991) 231 i'.H. J. Bachler el. al (J. Bartke, E. Gladysz, M. Kowalski): Study of the energy flow in sulphur mid oxygen nucleus collisions of 60 and 200 GeV/nucleon. Z. Phys. C52 (1991) 239 257 High Energy Nuclei Interaction Group 29. J. Gress et al (S. Mikocki, A. Trzupek): Identification of particles in air showers using tracking chambers and a thin absorber. Nuclear Instruments and Methods in Physics Research A302 (1991) 368 30. S. Mikocki et al (A. Trzupek): Monte Carlo simulation of extensive air showers initiated t>y gamma rays and protons. J. Phys. G: Nucl. Part. Phys. 17 (1991) 1303 31. A. Trzupek et al (S. Mikocki): The angular distributions of charged secondaries in elec- tromagnetic and hadronic extensive air showers at 10, 100, 1000 and 10000 TeV. J. Phys. G: Nucl. Part. Phys. 17 (1.991) 119 DELPHI 32. DELPHI Collaboration, P. Aarnio et al (Z. Hajduk, P, Jałocha, W. Janczur, P. Kapusta, B. Kisielewski, K. Korcyl, J. Michalowski, G. Polok, M. Turała, A. Zalewska): The DEL- PHI detector at LEP-CERN-PPE/90-128. Nuclear Instruments anu Methods in Physics Research A303 (1991)233 33. DEI PHI Collaboration, P. Abreu ec al (Z. Hajduk, P. Jalocha, P. Kapusta, K. Korcyl, W. Krupiński, H. Pałka, G. Polok, M. Turała, A. Zalewska): Charged particle multiplicity distriutions in Z° hadronic decays. CERN PPE/90-173, Z Phys. C50 (1991)185 34. DELPHI Collaboration, P. Abreu et al (Z. Hajduk, P. Jałocha, P. Kapusta, K. Korcyl, W. Krupiński, H. Pałka, G. Polok, M. Turała, A. Zalewska): Experimental study of the triple-gluon vertex. Phys. Lett. B255 (1991) 466 35. DELPHI Collaboration P. Abreu et al (Z. Hajduk, P. Jałocha, P. Kapusta, K. Korcyl, T.V. Krupiuski, H. Pałka, G. Polok, K. Rybicki, M. Turała, A. Zalewska): A study of the reaction e+e~ -» fi+ii~ around the Z° pole. CER.N-PPe/91-43, Phys. Lett. BZGO (1991) 240 36. DELPHI Collaboration, P. Abreu et al (Z. Hajduk, P. Jalocha, P. Kapusta, K. Korcyl, W. Krupiński, H. Pałka, G. Polok, K. Rybkki, M. Turała, A. Zalewska): Charged particle multiplicity distributions in restricted rapidity intervals in Z° hadronic decays. CERN- PPE/91-78, Z. Phys. Lett. C52 (1991) 271 37. DELPHI Collaboration, P. Abreu et al (Z. Hajduk, P. Jalocha, P. Kapusta, K. Korcyl, W. Krupiriski, H. Pałka, G. Polok, K. Rybicki, M. Turala, A. Zalewska): The reaction e+e- _> 77(7) at z° energies. CERN-PPE/91-109, Phys. Lett. B268 (1991) 296. 38. DELPHI Collaboration, P. Abreu et al (Z. Hajduk, P. Jalocha, P. Kapusta, K. Korcyl, W. Krupiński, H. Pallca, G. Polok, K. Rybicki, M. Turała, A. Zalewska): A measurement of the lifetime of the tau lepton. CERN-PPE/91-115, Phya. Lett. B267 (1991) 422. 39. DELPHI Collaboration, P. Abreu et al (Z. Hajduk, P. Jałocha, P. Kapusta, K. Korcyl, W. Krupiński, H. Pałka, G. Polok, K. Rybicki, M. Turala, A. Zalewska): Search for neutral higgB particles in Z° decays. CERN-PPE/91-132, Nuci. Phys. B342 (1991) 40. DELPHI Collaboration, P. Abreu, P. KapuBta, K. Korcyl et al., Determination of the Z° resonance parameters and couplings from its hadronic and leptonic decays Nucl. Phys. B367 (1991) 511. 41. CRYSTAL BALL Collaboration, A. Bizetti et al (G. NOWBK): Measurement of the direct photon spectrum from T(l5) decays. Phys. Lett. B267 (1991) 286. 42. CRYSTAL BALL Collaboration, D. Antreasyan et al (G. Nowak): Measurement of the branching ratios for the decays and r -*• hadronn°u r -> hadronir°ir°v. Phys. Lett. B259 (1991) 216 43. Luis Labarga et al (M. Turala): The Mark II silicon strip vertex detector and performance of a silicon detector telescope in the Mark II detector at the SLC. IEEE Transactions on Nuclear Science vol. 38. No 1, Febr. 1991. 44. I. Hietanen et al (M. Turala): Beam test resultB of an ion-implantedBjlicon strip detector on a 100 mm wafer. Nuclear Instruments and Methods in Physics Research A305 (1991) 173-176. + 45. S. Barlag, M. Witek et al : Production properties of D°, D r D*~&ndD+ in 230 GeV n~ and K~ - Cu interactions. Z. Phys. C49 (1991) 555 48. S. Barlag, M. Witek et al: Azimuthal correlations between charmed particles in 230 GeV v~ - Cu interactions. Phys. Lett. B257 (1991) 519 259 Submitted for publication 1. V. A. Korotkov et al (T. Coghen): Bose-Einstein correlations in neutrino interactions. Submitted to the joint international lepton-photon symposium and europhysica conlerence on high energy physics, Geneva, 1991 2. DELPHI Collaboration, P. Abreu et al (Z. Hajduk, P. Jalocha, P. Kapusta, K. Korcył, W. Krupiński, H. Palka, G. Polok, K. Rybicki, M. Turała, A. Zalewska): Study of orientation of 3-jet events in Z° hadron'c decays using the DELPHI detector. CERN-PPE/91-79, Submitted to Phys.Lett. 3. DELPHI Collaboration, P. Abreu et al (Z. Hajduk, P. Jaiocha, P. Kapusta, K. Korcyl, W. Krupiński, H. Palka, G. Polok, K. Rybicki, M. Turala, A. Zalewska): Determination of Z° resonance parameters and coupling from its hadronic and leptonic decays. CERN- PPE/91-95, Submitted to Nucl. Phys. 4. DELPHI Collaboration, P. Abreu et al (Z. Hajduk, P. Jalocha, P. Kapusta, K. Korcyl, W. Krupiński, H. Pałka, G. Polok, K. Rybicki, M. Tuxala, A. Zalewska): Search for excited charged leptons in Z° decays. CERN-PPE/91-100, Submitted to Z. Phys. 5. DELPHI Collaboration, P. Abreu et al (Z. Hajduk, P. Jałocha, P. Kapusta, K. Korcyl, W. Krupiński, H. Palka, G. Polok, K. Rybicki, M. Tiirała, A. Zalewska): Measurement of the average lifetime of the B hadrons. CERN-PPE/9M31, Submitted to Z. Phys. C 6. DELPHI Collaboration, P. Abreu et al (Z. Hajduk, P. Jabcha, P. Kapusta, K. Korcyl, W. Krupiński, H. Palka, G. Polok, K. Rybicki, M. Turała, A. Zalewska): Search for scalar leptoquarks from Z° decays. CERN-PPE/91-138, Submitted to Phys. Lett. 7. DELPHI Collaboration, P. Abreu et al (Z. Hajduk, P. Jałocha, P. Kapusta, K. Korcyl, W. Krupiński, H. Palka, G. Polok, K. Rybicki, M. Turala, A. Zalewska): Study of final state photons in hadronic Z° decay and limits on new phenomena. CERN-PPE/91-174, Submitted to Z, Phys. C 8. DELPHI Collaboration, P. Abreu et al (Z. Hajduk, P. Jałocha, P. Kapusta, K.Korcyl, W. Krupiński, H. Pałka, G. Polok, K. Rybicki, M. Tiirała, A. Zalewska): Searches for heavy neutrinos from Z° decays. CERN-PPE/91-175, Submitted to Phys. Lett. 9. DELPHI Collaboration, P. Abreu et al (Z. Hajduk, P. Jalocha, P. Kapusta, K.Korcyl, W. Krupiński, H. Pałka, G. Polok, K. Rybicki, M. Tuxala, A. Zalewska): Production of strange particles in the hadronic decays of the Z°. CERN-PPE/91-207, Submitted to Phys. Lett. 10. DELPHI Collaboration, P. Abreu et al (Z. Hajduk, P. Jalocha, P. Kapusta, K.Korcyl, W. Krupiński, H. Palka, G. Polok, K. Rybicki, M. Turala, A. Zalewska): A measurement of sin2 ©wfrom the charge asymmetry of hadronic events at the Z° peak. CERN-PPE/91- 211, Submitted to Phys. Lett. 260 11. DELPHI Collaboration, P. Abreu et al (Z. Hajduk, F. Jałocha, P. Kapusta, K.Korcyl, W. Krapiński, K. Pałka, G. Pclok, K. Rybicki, M. Turała, A. Zalewska): A measurement of the bb forward-backward asymmetry using the semileptonic decay into rnuons. CERN- PPE/91-213, Submitted to Phys. Lett. 12. CRYSTAL BALL Collaboration, T. Leisiak et al (G. Nowak): Search for radiative B meson decays. Preprint DESY-91-075 (1991), Submitted to Z. Phyo. C. 13. CRYSTAL BALL Collaboration, D.Antreasyan et al (T. Lesiak) Search for D° and B° decayo into TTV. Preprint DESY-91-076 (1991) Submitted to Z. Phys. C. 14. CRYSTAL BALL Collaboration, M. Kobel et al (T. Lesiak, G. Nowak): Measurement of the decay of the T(1S) and T(2S) resonances to muon pairs. Preprint SLAC-PUB-5402 (1990) Submitted to Z. Phys. C 15. P. A8pell et al (A. Czermak, P. Jalocha, M. Turala: CMOS low noise monolithic frontends for Si strip detector readout. CERN-PPE/91-154, Sept.1991 Submitted to Nucl. Instr. Meth. A. 16. R. G. Jacobsen et al (M. Turala): Measurement of the 65 fraction in hadroiic Z° decays with precision vertex detectors. SLAC-PUB-5603, LBL-31095, July 1991 Submitted to Ohysical Review Letters. 17. C. Adolphsen et al (M. Turala): The Mark II silicon Btrip detector. Preprint SLAC-PUB- 5443, Aug,1991 Submitted to Nucl. Instr. Meth. 18. J. Ellet et al (A. Czermak): Development and test of a large silicon atrip system for a hadron collider beauty trigger. CERN-PPE/91. Submitted to Nucl. Instr. Meth. 261 Conference reports and preprints 1. M. Kowalski and NA35 Collaboration: Production of charged kaons in central S+S colli- sions at 200 GeV/nucleon. Proc. XXVI rencontreB de Moriond, 1991, p.257 2. M. Kowalski and NA35 Collaboration: Production of charged kaons in central S+S colli- sions at 200 GeV/nucleon. Proc. int. lepton-photon symposium and europhysica confer- ence on high energy physics, Geneya 1991, to appear 3. M. Kowalski, J. Bartke, E. Gladysz, P. Stefański, et ah Production of charged kaons in central S+S and O+Au collisions at 200 GeV/nucleon. Proc. quark matter '91, Gatlinbujg 1991, to appear, 4. J. Bartke, E. Gladysz, P. Stefański and NA35 Collaboration: Fractal characteristics of multiple final states in relativistic heavy jon collisions. Poster N° E-42, Quark matter '91 conference, Gatlinburg, USA 1991. 5. J. Bartke, E.Gladysz, P. Stefański and NA35 Collaboration: Fluctuations of multiplicities in rapidity windows in sulphur-sulphur collisions at 200 GeV. Poster N° E-44, Quark matter '91 conference, Gatlinburg, USA 1991. 6. M. W. Krasny et al : Determination of the longitudinal structure function at HERA from radiative events. DESY 91-117, DPhPE 91-11 7. B. Wosiek: Fluctuations and intermittency in high energy nucleus-nucleus collisions. Ra- port Nr 1533/PH Inst. of Nucl. Phys. 8. P. A. Goriczew et al (B. Wiiczyńska, H. Wilczyński, W. Wolter, B. Wosiek, A. Olazewski, A. Jurak): Ispuskanie zariazennych czastic e kineticzskoj enargiej do 30 MsV/nuldon pri wzaimodiejstwii neitrino so średniej energiei 0 GeV s tjagelymi jądrami w fotoemulBJi. Preprint ITEP 91-14 MoBkwa. 9. K. Asakimori et al (R. Hołyński, A. Jiirak, B. Wooiek, B. Wiiczyńoka, H. Wilcsyński, W. Wolter ): Energy spectra and compositior of cosmic rays above 1 TeV per nucleon. Proc. XXII ICRC (Dublin) 1991 10. K. Afjakimori et al (R. Hołyńoki, A. Jurak, B. Wśksyńsks, H. Wilcsyński, W. Wolter, B. Wosiek): Energy spectra of proton and helium nuclei above 5 TeV/nuci. Proc. XXII ICRC (Dublin) 1991 11. M. L. Cherry et al (A. Dąbrowska, R. Hołyńeki, A. Jurakf A. Olssewaki, M. Ssarska, A. Trzupek, B. Wiksyńska, H. Wiicsyńoki, B. Wosiek, K. Woźniak): Comparison of particle production in the forward rapidity ragioa in protojŁ-audiEEB and nucleus-nucleus interactions. Proc. XXII ICRC (Dublin) 1991 JFS Raport Nr 1505/PH 262 12. M. I. Cherry et al (A. Dąbrowska, R. Hołynski, A. Jurak, A. Olszewski, M. Szarsks., A.Trzupek, B. Wilczyńska, H. Wllczyńskl, B. Woaiek): Multiplicities in nucleus-nucleus interactions at the highest accelerator energies. Proc. XXII ICRC (Dublin) 1991 1FJ Raport Nr 1566/PH 13. K. Aaakimori et el (R. Holyriski, A. Jurak, B. WilczynBka, H. Wikzynski, W. Wolter, B. Wosiek ): Ultra-relativiatic heavy nucleus interactions in the energy range above 500 GeV/Nucleon. Proc. XXII ICRC (Dublin) 1991 14. K. Aaakimori et al (R. Holyriski, A. Jurak, B. Wilczyńska, H. Wilczyński, W. Wolter, B. Wosiek ): Three-dimentional simulations of calorimeter X-ray film spots for determining PT- Proc. XXII ICRC (Dublin) 1991 15. K. Asakimori et al (R. Holyński, A. Jurak, B. Wilczyńska, H. Wilczyński, W. Wolter, B. WoBiek ): Simulation study for JACEB emulsion chambers. Proc. XXII ICRC (Dublin) 1991 16. K. Asakimori et al (K. rfołyński, A. Jurak, B. WilczyńBka, TL Wilczyński, W. Wolter, B. Wosiek ): A measiutiii^nt of the Landau-Pomeranczuk-Migdal effect in electromagnetic Bhowers. Proc. XXII iCHC (Dublin) 1991 17. Y. LU et al (A. Trz ;pek): Measurement of the angular correlation between primary cosmic ro.ys and single ma > is at sea level using the moon's shadow. Proc. XXII ICRC (Dublin) 1991 18. A. Trzupek et al : Secondary mucn/electron identification in thin steel absorber. Proc. XXII ICRC (Dublin) 1991 19. J. Poirier et al (A. Trzupek): Status of project GRAND. Proc. XXII ICRC (Dublin) 1991 20. A. Trzupek et al : The secondary gamma ray composition of cosmic rays. Proc, XXII ICRC (Dublin) 1991 21. J. Poirier et al (A. Trzupek): All-sky survey for compact stellar sources yielding secondary muons at sea level. Proc. XXII ICRC (Dublin) 1991 22. W. Dąbrowski et al(M. Kajetanowicz, M. Turala): Noise measurement on radiation- hardenet CMOS transistors. SCIIP 91/24, Sept.1991 Presented at the IEEE nuclear science symposium, Santa Fe, November 5-9,1991. 23. CRYSTAL BALL Collaboration, K. Karch et al (T. Leaiak, <3. Nowak): Analysis of the T77r°7r0 final state in photon-photon collisions. Preprint DESY-91-126(1991). 24. DELPHI Collaboration ,P. Abreu et al (Z. Hajduk, P. Jałocha, K. Korcyl, W. Krupiński, H. Palka, G. Polok, K. Rybicki, M. Turala, A. Zalewska): DELPHI results on the Z° resonance parameters through its haćbonk and leptonłc decay modes . Contribution to the Aspen conference January 1991, DELPHI 90-82 PHYS 80. 263 25. P.Abreu, K.Korcyl et al.r A measurement of the bh forward backward asymetiy using the semileptonic decay into muona. CERN PPE 91-211 26. P.Abreu, K.Korcyl et al.: Multiplicity dependence of mean transverse momentum in e+e" anihillationa at LEP energies. CERN PPE 91-213 27. P.Abreu, K.Korcyl et al.: Production of strange particles in the hadxonic decays of the Z°. CERN PPE 91-207 28. P.Abreu, K.Korcyl et al.: Determination of a, in second order QCD in hadronic Z° decays. CERN PPE 91-181 29. P.Abreu, K.Korcyl et al.: Searches for heavy neutrinos from Z° decays. CERN PPE 91-175 30. P.Abreu, K.Korcyl et al.: Study of final state photons in hadronic Z° decay and limits on new phenomena. CERN PPE 91-174 31. P.Abreu, K.Korcyl et, al.: Search for scalar leptoquarks from Z° decays. CERN PPE 91-138 32. P.Abreu, K.Korcyl et al.; Measurement of the average lifetime of B hadxons. CERN PPfi 91-131 33. P.Abreu, K.Korcyl et nl.: A search for neutral Higgs particles in Z° decays CERN PPE 91-132 34. P.Abreu, K.Korcyl et al.: The reaction <+e~ - - > 77(7) at Z° energies. CERN PPE 91-109 35. P.Abreu, P.Kapusta, K.Korcyl et al.: Study of orientation of 3-jefc events in Z° hadronic decays using the DELPHI detector. CERN PPE 91-79 36. P.Abreu, K.Korcyl et al.: Search for excited charged leptons in Z° decays. CERN PPE 91-100 37. J.EUet, A.Czermak et al.: Development and test of a large silicon strip system for a hadron collider beauty trigger. CERN PPE 91-217 rev 3G. P.Aspell, A.Czermak et al.: CMOS low noise monolithic frontends for Si strip detector readout. CERN PPE 91-154 39. J.Olszowskaet al.: Assigment of calibration pulser outputs, bias supply and analog display numbers to the BEMC stacks. Hl-BEMC note 13-91 40. W.Dabrowski, M.Kajetanowicz et al.: Noise measurements on radiation-hardened CMOS transistors, presented at the IEEE Nuclear Science Symposium Santa Fe, NM, November 5-9,1991 264 41. W.Iwanakl, P.KapusU: Level 2 trigger system In LHC calorimeter. CERN/EAST note 91-17 42. G.Appelquiflt, W.Iwanaki: Simulations of a FERMI board using VHDL. CERN/EAST note 91-18 265 Teaching activity The HEPL staff participates in the education process of physics students from the JagcHonian University in Cracow and supervision of M.Sc. and Ph.D theses. The following staff members participated in the activity in 1991: Lectures and Seminars: Prof. J. Bartke: "Experimental high energy particle physics" part II, V year Jagiellonian Univ. Prof. T. Coghen Seminar V year Jagiellonian Univ. Dr. L. Gorlich Seminar FV year Jagiellonian Univ. Dr.hab. M. Jeżabek "Some topics from theoretical elementary particie physics" IV year Jagiellonian Univ. Dr. hab. P. Malecki "Methods in high energy particle physics" part I, IV year Jagiellordan Univ. Dr. G. Nowak Seminar IV year Jagiellonian Univ. Prof. K. Rybicki "Experimental high energy particie physics" part I, V year Jagielionian Univ. Dr. A. Trzupek Seminar IV year Jagisllonian Univ. Prof. M. Turała "Method :n high energy particle physics" part 11, Iv year Jagiellonian Univ. Dr. hab. Z. Wąs " Some topics from theoretical elementary particle physics" IV year Jagiellonian Univ. Prof. K. Zalcwski "Quantum mechanics" III year Jagiellonian Univ. 266 Degrees obtained in 1991 (nam© of supervisor in parenthesis) M. Sc. A. Budziak: "Modelowanie kalorymetru typu 'spaghetti' dla fabryki mcxonow 13" (Dr. bab. M. Różańska ) K. Cetnar: "Analiza rozkładów krotności i funkcji struktury w oddziaływaniach fi — p dla energii 470 GeV" (Dr. hab. P.Malecki ) Ph. D T. I^csiak: "A search, for the process 6 —* 8 + 7" (Prof. K. Rybicki ) M. Witek: "A study of charmed mesons (D, D* and Dt) production in hadxon-hadron interactions" (Prof. K. Rybicki ) llabilita'ion M. Różańska: Badanie oddziaływań protonów i antyprotonów z jądrami pray energii 120 GeV Z. Was: Opis procesów produkcji i rozpadu par elemen- tarnych fermionów w zakresie energii LEP I H. Wosiek Fluctuations and intermiUency in high energy nucleus-nucleus collisions. 267 List of internal seminars 09.01.1991 dr Rudolf K. Bock (CERN) "LHC (Large Hadron Collider) - Phyaics Accelerator, Detector Development" 16.01.1991 prof, dr hab. Kacper Zalewski (Zakład V IFJ) "Nowa moda w Teorii Słabych Rozpadów CząBtek Zawierających Ciężkie Kwarki" 23.01.1991 dr G. Bachy, dr P. E. Faugeran (CERN) "The LHC Machine; Some of Its Technical Challenges" 30.01.1991 dr Jan M. Zazula (Zakład VI IFJ) "Niskoenergetyczne Neutrony w Kaskadach Hadronowych: Przegląd Kodów Monte Carlo i Symulacji w DESY" 20.02.1991 mgr Piotr Strzałkowski (Cyfronet-Świerk) "EXIS - System do Projektowania i Symulacji Experymentow Fizyki Cząstek Elementarnych" 27.02.1991 dr Agnieszka Zalewska (Zakład V IFJ) "Co Delfici uzyskali z Danych Zebranych w 1990 roku" 06,03.1991 dr Marek Gazdzicki (IFD UW) "Zderzenia Au+Au przy y/SNN = 200 GeV Projekt Eksperymentu STAR (RHIC)" 13.03.1991 prof, dr Reinhard Brandt (Philipps University, Marbirrg, RFN) "Anomalons Revisited" 20.03.1991 dr Volker Eckardt (MPI Munchen) "A Large Time Projection Chamber in the NA35 Heavy Ion Experiment" 27.03.1991 dr. M. Kowalski "Produkcja Naładowanych Kaonów w Centralnych Zderzeniach S+S przy 200 GeV/nuMeon" 10.04.1991 dr Aima Peisert-Eliiott (CERN) "Detektory Krzemowe i Ich Zastosowanie w Wielkich Eksperymentach (DELPHI)" 268 17.04.1991 mgr Piotr Szymański (EPJ) "Symulacja Działania i Niektóre Zaatosowania Liczników Wyzwalających Kalorymetru Elektromagnetycznego przy Eksperymencie DELPHI" 24.04.1091 mgr Józef Złomańczuk" (IFD UW) "Korelacje Protonów o Zbliżonych Pędach w Oddziaływaniach o Energii Kilku GeV/nukleon" 08.05.1991 dr Marilisa Turleur (CEN Saclay) "Recent Results on Z° -* bb DecayB Obtained with the DELPHI Detector at LEP" 15.05.1991 prof, dr hab. Jerzy Bartke "Rozkłady Energii Poprzecznej w Zderzeniach Jąder Atomowych Przy Energii 200 GeV/nukleon (Eksperyment NA35)" 29.05.1991 dr Grzegorz Polok "Detektor Barrel-RICH w Eksperymencie DELPHI" 26.06.1991 prof. Kim Egiyan (Yerevan, CEBAF) "Elektron-Nuclear Physics Program of YERPP 03.07.1991 mgr Jacek Kosiec (IFD UW) "TPC w Eksperymencie z Relatywistycznymi Ciężkimi Jonami" 02.10.1991 dr Grzegorz Polok, mgr. A. Sobala "Vax-cluster - Informacje Dla Użytkowników" 23.10.1991 prof. Michał Imała "Spektrometr EAGLE dla Eksperymentów na LHC" 29.10.1991 prof. T. Romanowski (Ohio State) "Neutrino Oscilation" 30.10.1991 prof. J.K. Bienlein (DESY & ETH/Zurich) "Rezonance Formation in 77 - Collisions As Seen By The Cristal Ball Detector" 13.11.1991 prof, dr hab. Jerzy Bartke, prof dr hab. Kacper Zalewslci "Konferencja EPS-Genewa 25.07-01.08.1991 - Joint International Lepton-Photon Symposium end Europhysics Conference on High Energy Physica" 269 20.11.1991 mgr Andrzej Qlszewski "Źródła Produkcji Cząstek W Schemacie Superpozycji Dla Oddziaływań Jąder z Jądrami" 27.11.1991 dr Tadeusz Lesiak, dr Maciej Zachara "Konferencja Fizyki Wysokich Energii Genewa, 25.07-01.08.1991 (czesc II)" 04.12.1991 dr Leszek SuBzycki (MIFTJ AGH) "Świetlność HERY dla ZEUSA - Pierwsze Pomiary" 11.12.1991 dr Agnieszka Zalewska "Krzemowy Detektor Wierzchołka Eksperymentu DELPHI - Pierwsze Wyniki Fizyczne 1 Perspektywy" 18.12.1991 dr Agnieszka Zalewuka "Krzemowy Detektor Wierzchołka Eksperymentu DELPHI - Pierwsze Wyniki Fizyczne i Perspektywy (cz. II)" Invited talks "Design Study of CMOS Amplifiers for Wire Chambers" A. Czermak, W. Dąbrowski, M. Dziaduś, P. Jałocha, M. Kajetanowkz, B. Kisłelewski, Z. Natkaniec, A. Skoczeń, M. Turała Presented by Michał Dziaduś at Strassburg CRN on 7 March 1991 "Detector R&D for LHC" Presented by M. Turała at Saint Felieu de Guixolu (Spain) on 10 May 1991. "LEP experience with Si-strip vertex detectors" Presented by M. Turała at Santa Fe on 3 November 1991 "DELPHI Microvertex Detector status and first physics results" Presented by M. Turała at Santa Cruz on 21 November 1991. "THE DELPHI microvertex detector: layou*-, first physics results and future upgrade." Presented by Agnieszka Zalewska at Sśminaire du Service de Physique des Particules on 25 November 1991. 270 List of foreign visitors in 1991 Dr, W.Bartel DESY (HI) Prof. J. K. Bienlein DESY (Crystal Ball) Prof. J. C. Bizot LAL Orsay (HI) Dr. G. Bachy CERN (LHC) Dr. P. Faugeras CERN (LHC) Dr. 0. Barbalat CERN (LHC) Prof. H. Hoffmann CERN (LHC) Dr. A. Czarnetzki DESY (HI) Dr. E. Bock CERN (LHC) Dr. A. Peysert-Eliot CERN (DELPHI) Dr. A. Poncet CERN (LHC) Dr. P. Rohmig CERN (LHC) Dr. X. Artru Lyon (Teoria) Prof. P. G. Innocenti CERN (LHC) Dr. F. Bourgeois CERN (LHC) Dr. H. Rossi CERN (LHC) Dr. M. L. Turluer CEN Saclay (DELPHI) Prof. T. Romanowski Ohio/DESY (ZEUS) Liz. I. Konovalov ITEP [KIM) Inz. M. Surenkov ITEP (KLM) Dr. J. P. Froberger CRNS Strasbourg (DELPHI) Prof. M. S chaffer CRNS (DELPHI) Dr. M. Plumer Marburg Univ. (NA35) Dr. P. Collas CEN (DELPHI) Dr. W. Geiat CRNS/CRN (NA36) Dr. V. Eckardt MPI Monachium (NA35) Prof. R. Brandt Marburg (Na35) Prof. R. Weiner Marburg (NA35) Prof. W. Busza MIT- (PHOBOS) Dr. K. Egiyan Armenia (NA35) 271 4 r Department of Applied Nuclear Physics ?4 S ' i : DEPARTMENT OF APPLIED NUCLEAR PHYSICS Head of the Department: Prof.dr Jan A. Czubek GENERAL INFORMATION: Research activity in the Department is performed by five laboratories: 1. Nuclear Geophysics and Hydrology (head: Professor Dr. Andrzej Zuber) 2. Gas Chromatography (head Dr. Jan Łasa) 3. Applied Electronics (head: Eugeniusz Mnich) 4. Neutron Material Parameters (head: Dr. Urszula Woinicka) 5. Nuclear Exploration Methods (head: Professor Dr. Jerzy Łoskiewicz). Total staff of the Department: 1 full Professor, 2 Associated Professors, 1 Assistant Pro- fessor, 5 doctors (including one with "habilitation" degree), 8 research physicists, 3 electronic engineers and 10 technicians of different specialties. They are working (both in the theory and in experiments) in following subjects: 1. Physics of tracer transport in porous (geological) media. 2. Physics of molecular phenomena in chromatographic detectors. 3. Physics of nuclear radiation transport in solids. 4. Physics of neutron interactions with nuclei (low energy region). 5. Physics of nuclear well loggings. The basic research is carried out in order to apply the results into the following problems: 1. Theory of solute transport in porous and fractured media for improvement of the interpretation of artificial and environmental tracer data. Studies related to determining the origin of formation waters from environmental isotope and radioiso- tope data. Both directions of studies are related to management and protection of groundwater reservoirs and mineral waters used for cure purposes (in close co- operation with the Faculty of Nuclear Physics and Techniques of the Academy of Mining and Metallurgy in Kraków and Institute fur Hydrologie, GSF, Neuherberg, Germany). 273 2. Design of chromatographic detectors and use of chromatography for analyt- ical and environmental problems (in close cooperation with the Faculty of Nuclear Physics and Techniques of the Academy of Mining and Metallurgy in Krakow). 3. Evaluation of neutron material cross sections needed in the calculations of radiation fields in the matter. 4. Theoretical and experimental determination? of neutron and radioactive pa- rameters of geological formations and technological parameters of some raw materials (mainly coals and coke). 5. Establishing the calibration procedures for neutron and gamma-ray well log- ging methods. (Here some collaboration is made with the Institute of Exploration Geophysics, of the Academy of Mining and Metallurgy in Krakow). 6. Mathematical modeling and design of gauges based on nuclear radiation to detect the water content, bulk density and other technological parameters of indus- trial materials (performed in collaboration with Physics Group of Kraków School of Economics). The results of basic research are published in the open literature, whereas the results of applied research made on the requirements from the industry or other research institutes are included in the internal reports. PERSONNEL: Jan A. Czubek, Professor — Head of the Department Research otaff: Joanna Bogacz, Teresa Cywicka-Jakiel, Bogdan Drozdowic^, Dominik Dworak, Krzysztof Drozdowicz, Barbara Gabańska, Ewa Krynicka, Jan Łasa, Jerzy Łoskiewicz, Prof., Piotr Maloszewski, Eugeniusz Mnich, Ireneusz Śliwka, Janusz Swakoń, Urszula Woźnicka, Jan Zazula, Andrzej Zuber, Prof., Technical staff: Jacek Burda, Edward Cichoń, Stanisław Kolber, Władysław Kowalik, Jadwiga Mazur, Jacek Nowaczyiiski, Antoni Rosciszewski, Grzegorz Tracz, Zbigniew Węgiel, Wiesław Wierba, Janina "Wojczuk-Wanic Administration: Ewa Lipka. 274 RESEARCH ACTIVITIES: Semiempirical calibration of neutron porosity tools. I. Formation and borehole salinity problems Jan A. Czubek First results of the semi-empirical approach to the calibration of neutron porosity tools have been carried out in fresh water saturated formations [1]. To apply this principle to boreholes filled with brines, some different approach is required. This is because, when integrating the neutron flux moments over the azimuthal angle for the sidewall tool position, variable brine salinities appear. For this purpose an approximating algorithm to calculate the neutron parameters of brines of variable salinity is needed. The parameters phiy pT),, %afp and pD are calculated first using the SLOWN [2] and NEROTH [3] programs. Then the density of brine should be known for a given temperature and pressure. First part of the work was focused on establishing the formulae for this density and on check of their validity. The check was carried out with experimental data and with data reported by some logging companies. Brine density for normal conditions is rather easy available. Experimental data for higher temperature are very scarce. The only available data were those of EUis and Golding [4j. The results obtained, when applying our math- Drtno dcimlty TO temperature forvarious brino salinities ematical formula (valid up to 250 Celsius) BiprrimonUl dniu: Kills Ic f.oldtng (lfl8U) and Tnl.lm to the experimental conditions used by 1.10 • those authors (0, 0.5, 1.0, 2.0, 3.0 molal NaCl, i.e. mols NaCl in 1000 g of water), U are shown in the figure. The continuous "o.oo lines drawn according to our formulae fit very well the interpretation charts of log- jjo.ao o IliO Bornej •ł- llrOlilUB ging companies [5].Their agreement with o n O.B m NaCl k l.OmNnCl experimental data for higher temperatures ao.70 * a.O m NaCl and brine salinities is rather poor. On the * 20 do(. Tabls other hand their fit to the experimental O.60 40 00 IZO I OD 200 240 2flO 320 360 data at norma] conditions is excellent. TEUPERATURE (Colsluu) Calculation of apparent neutron parameters for the borehole/rock formation configuration with different salinities will be the next step of the present work. References: [1] J.A.Czubek, Calibration of neutron porosity tools using semi- empirical approach. Proc. SPWLA 31st Annual Logging Symp,, June 24-27, 1990, Houston TX, Paper QQ, 18p. [2] J.A.Czubek, SLOWN2.BAS Program for calculations of the rock neutron slowing down parameters. Rep. INP No 1397/AP, Krakow 1988, 53p. [3] J.A.Czubek, NEROTH.BAS Program for rock thermal neutron parameter calcu- lations. Rep. INP No 1403/AP, Krakow 1988, 51p. [4] A.J.Ellis and R:M.Golding, The solubility of carbon dioxide above 100 Celsius in water and sodium chloride solutions. Amer. J. Sci., v. 262, Jan. 1963, 47-60. (5] Halliburton Logging Services, Inc. Log Interprertation Charts. First Printing 1991, Houston TX. 275 Earth's Ozone layer J. Lasa The paper contain the actual results of investigations of the influence of the human activity on the Earth's ozone layer. History of the ozone measurements and of the changes in its concen- trations within the last few years are given. The influence of the trace gases on both local and global ozone concentrations are discussed. The probable changes of the ozone concentrations are presented on the basis of the modelling investigations. The effect of a decrease in global ozone concentration on human health and on biosphere are also presented. GAIA hypothesis J. Lasa The paper presents the hypothesis whose basic theorem is that the Life in the form of the biosferę is not the result of found conditions, but it controls the climatic conditions of the Earth. The control process occurs in the limits of the global cybernetic system which is called Gala. Through the production of greenhouse gases and of carriers of the elements neccesary for the existence of the Life, the system influences the climatic conditions and modifies them to suit the optimal parameters for the Life. The role of man existing within the Gaia system and his permissible activities nondestructive to the mutual coexistence are discussed.' Hypercoulometric effect in an electron capture detector polarized with an additional voltage J. Lasa, I. Śliwka, B. Drozdowicz. This paper reports measurements of the ciurent characteristics and of the signal correspond- ing to a constant concentration of Freon F-11 for an electron-capture detector, supplied with a pulse voltage with a changeable pulse duration, amplitude and repetition time. It was found that an additional voltage applied to the detector cathode increased the detector signal about 50 V. The influence of the polarized voltage on the electron capture efficiency coefficient (p) measured with two detectors in series was demonstrated and the ^liability of the sample mass calculation by means of (p) is discused. Greenhouse affect J. Lasa The paper concerns results of research of man activities effecting a greenhouse effect. In- fluence of atmunpherk trace gases on global climate was described. A social and economical repercussion connected with increase of Earth's temperature and climate change was discused. Possible research programs and internationals efForts for reduction of the greenhouse effect was givon. 276 Device for measuring the moisture of the agglomerate mixture of the ore-iron with corrections depending on density E. Mnich and R. Grzyborowski This equipment design is based on the research results obtained by R. Matlag, J. Bogacz, J. Łoskiewicz and M. Mnich. The agglomerate mixture of ore-iron to be sintered in agglomerating plant should first be properly granulated. The quality of the granulation depends on proper moisture conditions. The neutron moisture gauge Type MWMS-1 of the agglomerate mixture measures the mois- ture of the agglomerate mixture of the ore-iron inside the container. The measurement will be performed in 4ff geometry and results will be transferred to the automatic control system. The gauge is based on the neutron slowing down effect. Fast neutrons emitted from the isotope source, placed in the probe, aTe slowed down by nucleons of the medium, strongest by hydrogen nucleons up to the moment of obtaing thermal energy. Density of the thermal neutron stream, registered by the detector inside the probe, is proportional to the volume density of hydrogen in the medium. When the hydrogen is in the form of water, and all other parameters of the medium are constant, the reading from the detector is proportional to the volume moisture of the medium. In technique, for the convenience is introduced the notation of the weight moisture: W p where: Wv - volume moisture , Ww - weight moisture, p - bulk density. Density of the agglomerate mixture is not constant, it changes within a wide range, and therefore bulk density in the container changes as well. This is why the results obtained by the neutron method of the moisture measurement must be corrected by the density measurement. The future device for measuring the moisture of the agglomerate mixture of the ore-iron contains (block scheme Fig.l): the neutron moisture gauge, the density gauge, the moisture corrector, measurement control system, moisture and density readout systems, control signals interface, digital information signals, analogue information signals, and also low and high voltage suppliers. Results of moisture measurements are transferred to the automatic control system in charge of water dosage for the optimization of the moisture of the agglomerate mixture. Technical data. 1. Measuring range: a. moisture: 0-i-12% (per weight ) b. density: 1.5-f 3.0 g/cm3 2. Measurement accuracy: 0.7% of moisture (per weight) 3. Measurement time: 120sec. 4. Source of fast neutrons: Pu-Be; 510 n/s. 5. Source of gamma radiation: Cs-137; activity: 40mCi. 277 6. B.eading of measurement: a. digital on the front panel b. print out on printer c. analog on the recorder 7. Results of measurement: a. parallel output in the code BCD; 9-bits information; lbit parity. b. analog output: 1) 0:5V; 2) 0:100mV 8. Start of measurement a) automatic, b)manual. 9. Casing: dust-proofness and drop-proofness. 10. Dimensions: a. measuring apparatus: 530x300x560 mm b. moisture probe: F 30 x 500 nun c. density probe: F 75 x 800 mm d. standarizator of moisture: F 450 x 420 mm e. standarizator of density: F 600 x 800 mm 11. Pov/er supply: 220V, 50Hz; power consumption: 100VA. HEOTRON PROBE MOISTliflE I ~1- MOISTURE MOISTURE GAUGE CORRECTOR READOUT MEASUREMertr CONTROL CONTROL SIGNALS SYSTEM INTERFACE DIGITAL fWFORMATION REGISTERS 5IGNALS LOW VOLTAGE SUPPLIERS I D ANALOGUE I CONVERTER INFORMATION SlONAls GAMMA PROBE DENSITY DENSITY GAUGE REGISTERS READOUT Fig. 1. Device for measuring the moisture of the agglomerate (block scheme). 278 Fast realtime 16-channels correlator '•••> T S. Kolber The correlator is being built for the measurment of specific energy of coals by means of the 12C determination using a correlation method using an isotope neutron source and a correlation detector. The correlator consist of a series of CAMAC blocks /Fig.l/ placed in the CAMAC crate and connected by a crate controller interface with the IBM PC XT/AT computer.This set makes possible data storage and computing sixteen cross-correlation coefficients. N N N for n = 1-5-16. Clock generator about 100 MHz secures the sampling time 200ns. The pairs of fast input registers R^x ,R„,i and Ry2 ,RX2 /Fig.2/ working alternately, ensure data storage, and transfer by the shift registers to circuits^ multiplier M1-S-M16. The partial results of the product are added in the 16-adders A1^A16. All the operations are performed in real time /Fig 3/, which means that during the sampling time T,j the correlated signals are stored in the input register pairs R^ ,R.j2 , and then in the same sampling time T,2 the correlated signals stored during sample time T,j are multiplied and added. In accordance with the program, the IBM PC XT/AT will bring the data from the buffer memory Bl-rB16, and computes 16-cross correlation coefficients.The basic block of the 16-chaiuiels correlator have mostly been realized on integrated circuits, type Advance Schottky. 2ATAWAY CAMĄC a/w iff Of Si I Fig. 1. Set of CAMAC blocks of 16-channełs correlator 279 WfiJ-1 WYJV WEJ2 WYJ* Fig. 2. Simplified block diagram fill _l Fiy. 3. Time-dependent thermal neutron field in bounded systems U. Woźnicka, K. Drozdowicz The work presents a solution of the time-dependent diffusion equation for a two-region bounded system. This solution provides a theoretical background for the laboratory method of measuring the thermal neutron macroscopic absorption cross section using small samples. The research has been stimulated by the neutron geophysics. The need to know tne neutron dif- fusion parameters (macroscopic absorption cross section in the first place) of geological samples has resulted from the progress in the application of neutron methods in geophysics. The description of the neutron field mentioned above, and of its dependence on the thermal neutron diffusion parameters with possible applicability to the measurement of the neutron diffusion parameters, are the main objects of this work. A full description of the time-dependent diffusion equation in two-regionTjounded systems both with spherical and cylindrical geometries is given. An application of the solutions to the measurement of the thermal neutron macroscopic absorption crosB section has been worked out. The paper [1] describing the considered problem consists of three main parts. 1. Description of the steady state and the time-dependent thermal neutron distribution. 280 2. Solutions of the diffusion equation in two-region bounded systems and its application in measuring the diffusion parameters of samples. 3. Comparison of the solutions obtained from diffusion theory to other neutron transport approximations. The interpretation of the measurement is performed within the diffusion approximation. In order to check the validity of this approximation, two-medium plane and spherical geometries have been studied in transport theory for neutrons of one speed. Some calculations in the P approximation have also been performed in order to compare its accuracy with that obtained within the diffusion approximation. A separate problem is the neutron energy spectrum in small bounded volumes. It is de- viated from the equilibrium distribution because of the leakage of neutrons from the system (the diffusion cooling). To approach the phenomenon theoretically one should know an energy dependence of the scattering cross section. Tlu's is a problem in the case of hydrogenous media. For the moderator used, Plexiglass, the cross section was measured first by Drozdowicz [2]. A work has been started to utilize these data and the theoretical model of the scattering kernel for some hydrogenous materials by Granada [3] to investigate more detailed the diffusion cooling in small hydrogenous volumes. References: [1] U. Woznicka, Report CTH-RF-87 (1991), Chalmers University of Technology, Goteborg. [2] K. Drozdowicz, Ann. Nucl. Energy 16 (1989) 275. [3] J.R. Granada, V.H. Gillette and R.E. Mayer, Phys. Rev. A36 (1987) 5585. Energy calibration of neutron detectors for the neutron spectrometer "TANSY" K. Drozdowicz, M. Hoek and D. Aronsson (CTH Goeteborg) TANSY is 14 MeV neutron spectrometer for the fusion plasma diagnostics built for JET. The spectrometer is based on neutron time-of-flight and recoiled proton energy measurement [1]. It consists of two branches of 3 proton detectors and 16 neutron detectors in each one. In such a case an efficient method for calibrating and checking detector performance is essential. The method for the energy calibration of the neutron detector arrays has been elaborated [2] utilizing a 60Co gamma source which is also used for other purposes in the spectrometer. The count rate is measured as a function of high voltage at a given discrimination level. The obtained distribution is differentiated and a maximum value is found which corresponds to the voltage at which the gamma peak passes throuhg the discrimination level. By repeating the measurement at different discriminations the experimental dependence between the discrimina- tion level and the high voltage is found as a straight line in a log-log diagram. Two calibration parameters for each detector are determined from a fit of these straight lines. A relation be- tween the detector responce for the gamma and neutron radiations is taken into account. The obtained calibration parameters of the detectors give an absolute relation between the output fast pulse amplitude and the energy of radiation fuT any detector high voltage. Tests of the cal- ibration method have been performed [3], A relation between the neutron detector calibration parameters and producer's technical data for the photomultipliers has been investigated and the twt> kinds of data correlate well. The calibration method has been used to get the detector settings for the TANSY neutron spectrometer [4]. Test procedures for the spectrometer during 281 its regular operation are proposed and a method is given to calibrate a future spare detector to be included in the array. References: [1] G. Grosshoeg et al., Nuci. Instr. ai.d Meth. A249 (1986) 468. [2] M. Hoek, K. Drozdowicz and D. Aronsson, Report CTH-RF-68 (1990), Chalmers Uni- versity of Technology, Goeteborg. [3] K. Drozdowicz, M. Hoek and D. Aronsson, Report CTH-RF-72 (1990), Chalmers Uni- versity of Technology, Goeteborg. [4] K. Drozdowicz, M. Hoek and D. Aronsson, Nucl. Instr. and Meth. A306 (1991) 315. Data aquisition system for pulsed neutron measurement A. Igielski, B. Gabańska, J. Dąbrowski, J. Burda, W. Kowalik An essential point of pulsed neutron measurement is the registration of the thermal neutron die-away curve after a fast neutron burst. For this purpose the multichannel scaling mode is used. In our applications the required parameters of multichannel scaling are as follows: dwell time from 1 to 5 microseconds, repetition time from 0.7 to 4 miliseconds. The described data acquisition system is used instead of the multichannel time analyser AC-256 in the control and data collection electronic system [1]. The system consist of the multichannel analyser Canberra 35 Plus, the fast multiscaler model 7880 , the analog to digital converter model 8075 and the IBM PC/XT computer connected to the MCA 35 Plus with model 3576 serial and parallel interfaces [2j. Start pulses from the neutron generator and measured pulses from the thermal neutron detector are provided to the system by the fiber optic links. It prevents the damage of the electronic equipment, which may occur as a result of high voltage breakdowns in the neutron generator. The whole system was assembled and checked. The software tool kit was checked and improved. The test measurements were done and the dead-time of the whole system was estimated. Now the system works routinally. Its disadvantage is a relatively long transmition time (about 10 ms) between the fast multiscaler and analyser but the internal structure of the fast multiscaler 7880 [3j does not allow to decrease it. References: [1] J.Burda, A.Igielski, W.Kowalik, INP Report No 1182/E (1982), Kraków. [2] CANBERRA Series Plus Multichannel Analyser. Operator's Manual Version 2. [3] CANBERRA Model 7880 Fast Multiscaler Operating Manual. Correlation of the sample absorption and the time decay of thermal neutrons in a bounded sample-moderator system E. Krynicka The thermal neutron macroscopic absorption cross section has been measured for numerous geological samples by Czubek's method [1], [2], [3], [4]. A wide range of the results obtained for many rock samples has been utilized to determine a correlation between the physical property (the time decay of thermal neutrons in a fixed sample-moderator system) and the absorption rate of the sample. Calculations show that a very good correlation exists [S]. This gives possibility of creating calibration curves which will allow us to determine the macroscopic absorption cross section of the rock matrix on the basis of only one measured decay constant value. References: [1] J.A. Czubek, J.Phys.D:Appl.Phys. 14 (1981) 779 282 [2] K. Drozdowicz, (1981) J.Phys.D:Appl.Phys .14 (1981) 793 [3] K. Drozdowicz and U. Woźnicka, J.Phys.D:Appl.Phys. 16 (1983) 245 [4] J.A. Czubek, K. Drozdowicz, B. Gabańska, A. Igielski, E. Krynicka-Drozdowicz and U. Woźnicka, NucI.Geophys. 5 (1991) 101 [5] E. Krynicka, INP Report No 1541/AP (1991), Institute of Nuclear Physics, Krakow. Applying the universal neutron transport codes to the / ;/, calculation of well-logging probe response at different rock ^ porosities J. Bogacz, J. Loskiewicz and J.M. Zazula The use of universal neutron transport codes in order to calculate the parameters of well- logging probes represents a new approach first tried in USA and UK in the eighties. This paper deals with first such an attempt in Poland. The work is based on the use of MORSE code developed in Oak Ridge National Laboratory in USA. Using GG MORSE code we calculated neutron detector response when surrounded with sandstone of porosities 19% and 38%. During the work it come out that it was necessary to investigate difFerent methods of estimation of the neutron flux. The stochastical estimation method as used currently in the original MORSE code (next collision approximation) can not be used because of slow convergence of its variance. Using the analog type of estimation (calculation of the sum of track lenghts inside detector) we obtained results of acceptable variance (20%) for source-detector spacing smaller than 40 cm. The influence of porosity on detector response is correctly described for detector positioned at 27 cm. from the source. At the moment the variances are quite large. References: [1] Case C.R."CNT-G Tool Response to Bed Boundaries", SPWLA Paper, 33-d Annual Logging Symposium (1982). [2] Straker E.A..Stevens P.N., Irving D.C., Cain V.R. "The MORSE Code - A Multigroup Neutron and Gamma-ray Monte Carlo Transport Code", ORNL-4585, Oak Ridge National Lab- oratory (1970). [3] Lichtenstein H., Cohen M.O., Steinberg H.A., Troubetzkoy E.S., Beer M. "The SAMCE Monte Carlo System for Radiation Transport and Criticality Calculations in Complex Configu- rations (Revision 7.0)", EPRI Computer Code Manual CCM-8, Research Project 972 (1979). [4] Shuttleworth E., Chucas S.J. "Linked Monte Carlo and Finite Element Diffusion Methods for Reactor Shield Design", Proc. 6-th ICRS on Radiation Shielding, Tokyo, 1, 180(1983). [5j Los Alamos Monte Carlo Group "MCNP - A General Purpose Monte Carlo Code for Neutron and Photon Transport", LA-7396, Los Alamos National Laboratory (1981). [6] Engle W.W. Jr. "User Manual for ANISN, a One-Dimensional Discrete Ordinates Trans- port Code with Anisotropic Scattering" USAEC K-1G93, Oak Ridge National Laboratory (1967). [7] Lathrop K.D. "THREETRAN: A Program to Solve the Multigroup Discrete Ordinates Transport Equation in (x,y,z) Geometry", LA-6333-MS,Los Alamos National Laboratory (1976). [8] Rhoades W.A., Simpson D.B., Childs R.L., Engle W.W. Jr. "The DOT-IV Two Di- mensional Discrete Ordinates Transport Code with Space Dependent Mesh and Quadrature", ORNL-TM-6529, Oak Ridge National Laboratory (1978). [9] Ellis D.V., Ullo J., Sherman H. "Comparison of Calculated and Measured Responses of a Dual-Detector Neutron Porosity Device", SPE 10 294, Am. Inst. of Mining, Metallurgical and Petroleum Eng. (1981). [10] Butler J., Clayton C.G. "A New Philosophy for Calibrating Oil Well Logging Tools Based on Neutron Transport Codes", SPWLA - Annual Logging Symposium (1982). 283 •> Optimization of neutron flux estimation methodes in the MORSE code as used in nuclear geophysics J. Łoskiewicz, J.M. Zazula This paper deals with optimization of neutron probe modelling in geological media using Monte Carlo computational methods. The effectiveness of stochastical estimation techniques of particle flux at defined points was studied when calculating the neutron field die-away curve in rock from isotopic neutron source. The rock taken was a homogenous sandstone of 14% porosity. In the Oak Ridge MORSE code, in addition to classical next collision method (UCP), were written 6 new versions of scoring procedure RELCOL. They were labelled as UCF1, UCF2, UCF3, BSA, TLP i ASI. First three methods ara aimed at decreasing computation time for the particular neutron history and following three are designed to diminish the size of statistical errors by avoiding the singilarity in the scoring function. The results were compared with the neutron die away curve calculated independly by using discrete-ordinates code ANISN. Methods labelled UCF2, BSA, TLP and ASI are giving better results than UCF up to 60 cm distance from source. At larger distances the results from statistical estimation methods are systematically too low. This is mainly due to worsening of the representation of neutron angular distributions by curtailed Legendre polynomial scries, which comes from cross-section data library which give typically only P3 or P5 approximation. Therefore for modelling with Monte Carlo methods the geophysical problems it is better to use analog type estimation, where however, the good use of machine particle population enrichment is circumstantial. 10-1 2.^> M»/ source If >°" !•:.« [nror-il/ V 10 •', 4ir. c 10 = io' U. I io " UCIO IKTI I1CK" z m-J D UCF3 DSA AS! r 10- « 10"-TT T •• 11 *- T r T-i-i i i i | i i i i t i-rr 0.00 20.U0 4000 6L1.(IU 80.00 100.00 SOURCE - DEIECIOR niSlANCE R (cm) References: [1] Ullo J., Nucl. Sci. Eng. 92, 228 (1986). [2] Cramer S.N., Gonnord J., Hendricks J.S., Nucl. Sci. Eng. 92, 280 (1986). [3] Hoffman T.J., Tang J.S., Trans. Am. Nucl.Soc. 46, 654 (1984). [4] Fraley S.K., Hoffman T.J.,NucI. Sci. Eng. 70, 14 (1979). [5] Rief H., Dubi A., Elperin T., Nucl. Sci. Eng. 87, 59 (1984). [6] Stewart J.E., Trans. Am. Nucl. Soc. 10, 643 (1978). [7] Jones D.G., J. of Nucl. En. 8, 233 (1981). [8] Emmet M.B., "The MORSE Monte Carlo Radiation Transport Code System", ORNL- 4972, Oak Ridge National Laboratory (1975). [9] Dubi A., Elperin T., Rief H., Am. Nucl. Energy 9, 675 (1982). 284 A comparison of multięroup neutron cross-section obtained from the ENDF/B-IV library with the Abagyan-Bondarenko (ABNC) library as used in geophysical calculations D. Dworak and J. Łoskiewicz Data from ABNC, a Russian multigroup library, has been compared with ENDF/B-IV- derived data calculated in our Laboratory. Total neutron cross-section group averages for isotopes and elements frequently encountered in geophysical calcidations were used for these comparisons. In a few cases large differences between these sets of data were found. The results also indicate that compatibility of fundamental data (cross-sections) from different evaluated nuclear data bases (e.g. ENDF and ENDL) can be very weak, at least for some energy ranges. ^16 • " ENDt MAT 784? Iret^ol Cdl M-ut uctien 4 •= SO 0 1/ fim itM. E ,fc* bcin uate -M> 0 ' 10"' 10' '0* 15 Cailfimini-ENDr MAT i:si iiuiuul Cdl n ABNC dm Tht itlamr iliITninct in lolil tfn-tfftipn fruup «vcr.ipct A funlinuniiMi'ufte c»! djii for AHNC-ENDL. References: [1] Abagvan L.P.,Bazazyants N.O.jBondai-enko I.I.,Nikolaev M.N (1964) Group Constants for Nuclear Reactor Calculations. Consultants Bureau, New York. [2] Abagyan L.P,Bazazyants N.O.,Nikolaev M.N.:Tsibula A.M. (1981) Group Constants for Reactor and Shielding Calculations (in Russian). Energoizdat, Moscow. [3] Butler J.,Locke J.,Packvood A. (1981) A new facility for the investigation of nuclear logging tools and their calibration. Proc. 27th Amvu. SPWLA Symp., Paper HHH. [4] Cullen D.E. (1988) The accuracy of processed nuclear data., Nucl. Sci. Eng. 99, 1972. [5] Cullen D.E.,McLaughlin P.K. (1985) ENDL-84. The Lawrence Livermore National Labo- ratory Evaluated Nuclear Data Library in the ENDF-V format. IAEA Report No. IAEA-NDS- 11, Rev.4. [6] Cullen D.E.,McLa-ighlin P.K. (1989) The 1989 ENDF/B pre-processing codes. IAEA Report No. lAEA-NDS-39,Rev.4. [7] Garber D.,Dunfort C.,Pearlstein S. (1975) Data formats and procedures for the Evaluated Nuclear Data File, ENDF. BNL Report No. BNL-NCS 50496. [8] Watson C. (1983) Numerical Simulation of g-ray logging of formation lithology. Proc. 58th Annu. SPE Symp.,SPE 12051, San Francisco. [9] Woolson W.A., Gritzner M.L. (1978) Evaluation models of active neutron logging tools for direct uranium measurements. SAI Report No. SAI-78-887-LJ. 285 z Computer assessment of the influence of humidity and ash h-\ content changes in Polish coals on their calorific value as measured using neutron inelastic scattering J. Loskiewicz, T. Cywicka-Jakicl, G. Tracz For the data coming from Upper Silesian Coal Basin it is shown in the paper that the disper- sion of the points about regression line is 1.2 to 4.8 smaller when using carbon concentration as calorific value indicator than when using ash. Calculations of the influence of" moisture and ash content on carbon g-ray signal from reaction 12C(n,n'7)12C were made using ANISN discrete ordinates code and BUGLE (DLC-75) neutron data library. The increase in ash content and decrease in carbon concentration caused by this fact decreases linearly the carbon 7-ray signal. The changes in carbon 7-ray signal caused by increasing coal humidity are small for bituminous coals. If we normalize at 5% humidity the size of carbon signal changes by less than 1.2% rela- tive. For lignites, however, which contain typically 50% water, the differences in carbon signal amount to 3% for 10% moisture change. The changes in ash elemental composition (with Fe2O3 variation between 12 and 34%) have only minor influence on carbon 7-ray signal. 30HC-OLKA+401W •ES : e •" i u\ s •: 000 . 3 OO 4ty> G 00 BOO • n»tgy c1 gommo - 'Or (M«v) Fto U Colculated aommo-rev spect'o from lignite! Df 2O« onij 4Oł fno;sture. References: [1] Stewart R.F., Instr. Soc. Am. Trans. 6 (1967) 200. [2] Sowerby B.D., Nucl. Instr. Meth. 160 (1979) 173. [3] Cywicka-Jakiel T.,Bogacz J.,Czubek J.A., Dąbrowski J.M., Łoskiewicz J., Zazula J.M., Inst. J. Appl. Radiat. Isot. 35 (1984) 7. [4) Dulong P., Fuel 12 (1933) 199. [5] Engle W.W., ORNL Report K-1693 (1967), Oak Ridge National Laboratory. [6] Roussin R.W., RSIC Data Library DLC-75, Report ORNL ANS-6.1.2 (1985). [7] Woolson W.A., Gritzner M.L, Nucl. Technol. 49 (1980) 410. [8] Zazula J.M., Thesis IFJ Report INP-1240/AP (1984). 286 [91 Zaziila J.M.,"BALTORO-A General Purpose Code for Coupling Discrete Ordinates and Monte Carlo Radiation Transport Calculation", INP Report 1228/AP (1983). [10] Mielecki T., GIG Publications, Katowice; Monography of Polish Coals, Ser. M. 1971 (in polish). Statistical comparison of potential precision of instrumental methods of coals calorific value measurement T. Cywicka-Jakiel, I. Hajrlas, J. Łoskiewicz In the paper is presented the analysis of the dependence of calorific value of coal Q on ash content A, carbon content C and moisture content W. Parameters of simple and multiple linear regression for Silesian, Lublin-Basin and US coals were calculated from the data yielded by analytical methods. The parameters obtained indicate better correlation of calorific value Q with < irbon content C than correlation of calorific value Q with ash content A. They show also a much smaller dispersion of experimental points about the regression line when carbon content is used as Q value indicator. This is expressed by the ratio of standard deviations Sy- /Sy ' obtained as equal to 2.92-V-0.62. These facts show that the carbon content measurements are better suited for a precise determination of calorific value Q than the ash content measurements. Neutron inelastic scattering reaction on carbon: 12C(n,n'7)12C could be applied to carbon content measurement. References: [I] Mielecki T., Prace GIG, Seria M, Monografia polskich węgli, (Monography of Polish Coals), 7j.i; Z.4, Kom.225 [2] Hodgeman CD., Weast R.C., Selby S., Handbook of Chemistry and Physics (Chemical Rubber Publishing Co., Cleveland 1955/1773. [3] Sowerby B.D., Nucl. Instr. Methods 160 (1979) 173. [4] Cywicka-Jakiel T.,Bogacz J.,Czubek J.A., Dąbrowski J.M., Łoskiewicz J., Zazula J.M., Inst. J. Appl. Radiat. Isot. 35 (1984) 7. [5] Proc. Advisory Group Meeting on Gamma, X-ray and. Neutron Techniques in the Coal Industry. Vienna 1986, p.4. [6] Dulong P., Fuel 12 (1933) 199. [7] Himus G.W., Fuel Testing London (1946). [8] Koch S., Technik 8 (1966) 501, 9 (1967) 903. [9] Watt J.S., Proc. Advisory Group Meeting on Gamma, X-ray and Neutron Techniques in the Coal Industry IAEA, Vienna 1986, p.113. [10] Klein A., Proc. 14th European Microwave Conf. Liege, 1984, p.661. [II] Janczyszyn J., Stochalski A., Analytica Chimica Acta 138 (1982) 199. [12] Mielecki T., "Węgiel-wiadomości o badaniu i własnościach węgla." Wyd. Śląsk, 1971. [13] Smirnow N.W., Dunin-Borkowski I.W., "Kurs rachunku prawdopodobieństwa i statystyki matematycznej dla zastosowań technicznych", (Probability and mathematical statistics for tech- nical applications), PWN Warszawa 1969, p.388. 287 The correlations between the concentrations of natural radiation elements (K, U, Th) and thermal neutron absorption r cross-section value (Sa) *° Carpathian rock samples .1. Swakon, T. Oywir.ka-Jakiel, E. Drozrlowic.z, B. Gabańska, J. Łoskiewicz, U. Woźnicka The paper presents a study of correlations between concentrations of potassium, uranium and thorium and thermal neutron absorption cross-section in rock samples. The knowledge of correlation should help in recognizing the ways of spreading and deposition of the elements responsible for high thermal neutron absorption cross-section in some geological environments. The correlations show the existence of connections between the thermal neutron absorption cross-section value and natural radioactivity elements concentration (particulary thorium) in rocks. The results confirm the existence of correlations between natural radioactive elements con- centrations (particulary between thorium and potassium) in west Carpathian rocks. 20 its )0 15 20 ppm Th **•*• tUPKt t MULOWCE CCCOO DOLOMJTY 1 tl^PJENIE acaoa PIASKOWCE 1 ZLEPIENCE ***** łTECIEL oo-»«o GRANITY CnWHKl ANHYDRYT 00000 MARG1EL References: [1] Perry E.A.Jr.,"Diagenesis and the Validity of the Boron Paleosalinity Technique", Amer- ican J. of Science, Vol.272 (1972) 150-160. [2] Filipów E.M., "Jadiernaja razwiedlca polieznych iskopajemych", (Nuclear Prospection for Mineral Resources),Kiev, 1981. [3] Zorski T., Ossowski A., "Spektrometryczne profilowanie naturabiej promieniotwórczości - nowe narzędzie p oszuki wan naftowych w Polsce" (SpectTometric logging of natural 7-radioactivity - a new tool in prospecting for oil), IV Krajowa Konf. Geofizyki Wiertniczej, Drzonkow 1988. [4] Serra 0., Baldwin J., Quirein J. "Theory, Interpretation and Practical Applications of Natural Gamma-ray Spectroscopy", SPWLA 21 ALS 1980. [5] Czubek J.A., "A Method for Measurement of Thermal Neutron Absorption Cross-section in Small Samples.", INP Report No. 1092/AP, 1980. [6] Czubek J.A., Drozdowicz K.,Igielski A..Krynicka E.,Sobczyński Z., Woźni cka U., J.Phys.D: Appl. Phys. 14 (1981) 977. [7] Drozdowicz K., J.Phys.D: Appl. Phys. 14 (1981) 793. 288 [8] Woźnicka U., J.Phys. D: Appl. Phya. 14 (1981) 1167. [9] Drozdowicz K., Woźnicka U., J.Phys.D: Appl. Phys. 16 (1983) 245. Estimation of the neutron field around the HERA proton beam dump H.J. MShring K.M.Universitat, Leipzig, Germany K. Noack Zentralinstitut fur Kernforschung, Rossendorf, Germany and J.M.Zazula. In this article we present estimates for the neutron fluences above 0.1 MeV to be expected around the proton beam dump of the HERA machine at DESY at 1000 GeV incident energy. The most important details of the absorber and tunnel layout are ap]ii«tjdmately modeled using the Cartesian and combinatorial geometry packages. In our method u volume neutron source for MORSE Monte Carlo neutron transport calculations has been determined from str»r densities obtained from the FLIIKA Monte Carlo hadronic shower code, combined with estimates of low- energy neutron yields based on results of intranuclear cascade calculations and of the statistical model of evaporation. The calculated neutron fluences are in reasonable agreement with results obtained by the FLUNEV version of the FLUKA code, currently developed at DESY, as well as with estimates based on empirically determined conversion factors between star density and neu- tron fluence. Additionally, we present neutron spectra and the corresponding dose equivalents as well as the absorbed doses in beam dump materials obtained from the FLTJKA code. Z O 050 Tif 4 fluerur ,(*ctrufn (.. fx- r*p<. !«ł:;, UtRA tunnel Mw Hie łicjm tluftip References: [1] For a recent review of the HERA collider see, e.g.: B.Wiik, HERA Status. Particle Accelerator Conf., Chicago,March 1989. [2] Stevenson G.R.,"Dose Equivalent per Star in Hadron Cascade Calculations", CERN Di- visional Report, TIS-RP/173, May 1986. [3] Tesch K.,Dinter H., Rad. Prot. Dosim. 15 (1986) 89. [4] Aarnio P.,Lindgren J.,Ranft J.,Fasso A.,Stevenson G., Enhancements to the FLUKA86 Program (FLUKA87), CERN Divisional Report, TIS-RP/190 (1987). 289 [5] Brrasheakov V.S.,Toneev V.P.,"High-Energy JIadron-nucleus and Nucleus-nucleus Inter- actions", Atomizdat, Moscow 1972. [6] Armstrong T.W.,Chandler K.C., Ni.d.Sci. Eng. 110 (1972) 110. f.7] Emmet M.B., "The MORSE Monte Carlo Radiation Transport Code System", Oak Ridge National Laboratory, Report ORNL-4912 (1972). [8] Zazula J.M., Tesch K., Nucl. Instr. and Meth. A286 (1990)279. [9] Zazida J.M., "User's Guide for the FLUNEV Code: An Extension of "the FLUKA High Energy Puticle Shower Code to Calculate Production and Transport of Secondary Neutrons Below 50 MeV", DESY Internal Report D3-6G (1990). Study of the neutron field from a hadronic cascade in Iron: verification of a Monte Carlo calculational model by comparison with measured data J.M. Zazula and K. Tcsch DESY, Hamburg, Germany The Monte Carlo code FLUNEV, an extension of the hadronic shower code FLUKA for production and transport of neutrons below 50 MeV, is modified by reduction bo.h of the lotal energy carried by intranuclear cascade particles and of the excitation energy preceding the evaporation step in inelastic hadron-nucleus collisions, following phenomenological suggestions given by Alsmiller and Alsmiller (Nucl. Instr. Meth. A278(1989)713) and by Barashenlcov et al. (Dubna report JINR/E2-89-437, 1989). The modified version of our code is verified by comparison with experimental neutron distributions around thin iron targets and thick iron absorbers irradiated by high energy protons, and with earlier calculations of neutron fields. Good agreement is achieved in most cases. 5LO' 5 10 20 i.oo " ' •(••"•- [ 4 • 200 on iron dump 0.S2 Ą * t> o A & f c O-l en O 0 A 0 4 A * 0 o co'cuiQied tiy rLunrv (rnoo .i,,*) 6 oo;> A. < coicuit (etf &v code O r 4 0 measi fpd by 'Ai(r..u)» No t t i . i 1 0 100 ?00 300 40O M0 600 700 POO PŁPTM IS IPOTJ [q.rrr.*r1 Fig ~ fn 1(1 II'. ;;|jiul tjla,!.,!.-,! - References: [1] Tesch K.,Dinter H., Radiat. Protection Dosim. 15 (1986) 89. [2] Thomas R.H.,Stevenson G.R., IAEA Technical Report Series, no. 283 (Vienna 1988) 290 [3] Russ J.S.»Stevenson G.R.,Fasso A.,Nielsen M.C.,Furetta C, Rancoita P.G., Vismara I., CERN Div. rep. TIS-JIP/89-02 (1989) [4] Zazula J.M.,Tesch K., DESY Report 89-064 (1989); Nucl. Instr. and Meth. A286 (1990) 27!). [5] Mphxing H.J.,Noack K.,Zazula J.M., DESY Report HERA 89-21 (1989). [6] Stevenson G.R., CERN Div. Rep. TIS-RP/173 (1986). [7] Hmngsen K.,Mphring H.J.,Ranft J., Nucl.Sci.Eng. 88 (1984) 551. [8] Ranft J., Z. Phys. C43 (1989) 439. [9] Barashenkov V.S.,Polanski A.,Sosnin A.N., Dubna Report JINR/E2-89-437 (1989). (10] Alsrniller F.S.,Alsmiller R.G.Jr., Oak Ridge National Laboratory rep. ORNL/TM-11032 (1985); Nucl. Instr. and Meth. A278 (1989) 713. [11] Alsmuler R.G.Jr.,AlsiniIler F.S.,Hermann O.W., Oak Ridge National Laboratory rep. ORNL/TM-11257 (1989); Nucl. Instr. and Meth. A286 (1990) 73. [12] Pearlstein S., Nucl. Sei. Eng. 95 (1987) 116. [13] Gabriel T.A.,Santoro R.T., Oak Ridge National Laboratory rep. RNL/TM-3945 (1972). Shielding properties of Iron at high energy proton accelerators studied by a Monte Carlo code K. Tesch DESY, Hamburg, Germany and J.M. Zazula Shielding properties of a lateral iron shield and of iron and concrete shields at angles between 5 and 30 are studied by means of the Monte Carlo program FLUNEV (DESY-D3 version of the FLUKA code extended for emission and transport of low energy neutrons). The following quantities were calculated for a high energy proton beam hitting an extended iron target: total and partial dose equivalents, attenuation coefficients, neutron spectra, star densities (compared also with the CASIM code) and quality factors. The dependence of the dose-equivalent on the energy of primary protons, the effect of a concrete layer behind a lateral iron shielding and the total number of neutrons produced in the target were also estimated. I.CO 0.50 . 0.10 5 Jl = 107 9-cm-' g 0.05 O 0 10 20 30 40 50 60 1HICKNE?r. Or WE COMCRCIE SHIELD (cm) IUd-jcti<.n nf ihr t < uin\'.iltnt K-IMII I :i LJII-'JI >fon thirtil ot 40 ijiti ink'kncM hy »n adtiilionn! concrete thielil. Tlie Mti-nu ii'ott MI * ("ii? concrete thirld ti militated by X. 291 References: [1] Zazłiin J.M., Tesrli K., DESV rq». 89-064 (1989); Nucl. Instr. and Meth. A28.J (1990) 279. [2] Zazula J.M.,Tesch K., tins issue, Nucl. Instr.and Moth. A300 (1991) 164. [3] Tcsch K., Zazula J.M., DESY rep. 90-037 (1990). [4] Tescli K.,Dinter H., Radiât. Protection Dosiin. 15 (1986) 89. [5] Thomas R.H.,Stevenson G.R., IAEA Technical Report Scries, no.238 (Vienna 1988). [fi] Bennet G.W.,L<>vinc G.S.,Fodsche H.W.,Toohing T.E., Nucl. Instr. and Meth. 118 (1974) 149. [7] Thomas R.H.,Thomas S.V., Health Phys. 46 (1984) 954. [8] Russ J.S..Stevenson G.R.,Fasso A.,Nielsen M.C.,Furetta C, Rancoita P.G., Vismara I., CJERN Div. rep. TIS-RP/89-02 (1989) (9j Zazula J.M., int. rep. DESY-D3-fiß (1990). [10] Aniio P.A., Liiiflgren J., Ranft J., Fasso A., Stevenson G.R., CERN Divis, reps. TIS- RP/168 (1986) and TIS-RP/IOO (1987). [1.1] Cloth P., Filges D., Sterzenbach G., Armstrong T.W., Colborn B.L.,TCFA Julic h rep. .lul-Spez-196 (1983). [12] Emmet M.D., Oak Ridge National Laboratory rep. ORNL-4972 (1975). [13] Alsmiller R.G.Jr., Barnes J.M., Drischlor J.D., Nucl. Instr. and Meth. A249 (1986) U5. \%\ Radiation doses and secondary neutron fluxes expected in the low-ibeta quadrupoles following the LHC interaction region G.R. Stevenson CERN, Geneva and J.M. Zazula Estimates have been made of the deposited power, secondary neutron flux density and absorbed dose in silicon which can be expected in different parts of the chain of four low-b quadrupoles on either side of an LHC interaction region. The 8 TeV p-p interactions were sim- ulated using the DTU.IET event generator and the FLUKA-N Monte Carlo program was used to follow the cascades induced by the secondary particles from the beam-beam collisions in the front collimator and the magnet structures. The calculated power levels were found to be close to the quench limit of superconducting magnets and the values of neutron fluence found were near to the operating limits of radiation-hard electronic devices. An effect of the magnetic field in the quadxupoles on the results was investigated. tenon point [rc| f'ieuir; 'Mr. lîrgiuii-avoriiçr'J IIOWT ileiiMtii/s alrsti: l.f.-il in i he different coils oft lie qiiarlrtipofes: ::ii!f.i.i-:ic iirl'i I-FI 292 References: [1] Arnio P.A., Lindgren J., Rwift J., Fasso A., Stevenson G.R., CERN Divi . reps. TIS- RP/168 (1986) and TIS-RP/190 (1987). [2j Alsmiller R.G.Jr., Barnes J.M., Drisdiler J.D., "Neutron-photon multigroup cross-sections for neutron energies i 400 MeV (Revision 1)", Nucl.Instr.Meth. A249 (1986) 445. [3] Cloth P.,Filges D.,Neef R.D., Sterzenbach G., Reul Ch., Armstrong T.W., Colborn B.L., Anders B., Brtckmann H., "HERMES - A Monte Carlo Program System for Beam-Materials Interaction Studies", KFA Julich Report Jtl-2203 (1988). [4] Ferrari A., Sala P., Guaraldi R., Padoani F., "An Improved Multiple Scattering Model for Charged Particle Transport", to be published in Nucl.Instr.Meth. (1991). [5] Iselin Ch., "Solution of Poisson's or Laplace's Equation in Two-Dimensional Regions", CERN Computer Center Program Library, CERNLIB-T604/POISCR (1984). [6] The LHC Study Group, "Design Study of the Large Hadron Collider (LHC)", CERN Report 91-03 (1991). [7] Nelson W.R., Hirayama H., Rogers D.W.O., "The EGS4 Code System", Stanford Linear Accelerator Center Report SLAC-225 (1985). [8] Ranft J., Hahn K., "DTUJET-88. Sampling Hadronic Events According to the Dual Topological Unitarization of Hard and Soft Hadronic Processes", CERN Divisional Report TIS- RP/218 (1988). Radiation levels in the LHC tunnel due to halo protons lost on LHC beam scraper G.R. Stevenson CERN, Geneva and J.M. Zazula The secondary particle cascades induced by the loss of 8 TeV beam halo protons on a tungsten beam scraper have been simulated using the FLUKA-N particle shower code. Estimates have been made of the star densities, secondary hadron fluences and neutron energy spectra in different regions and various materials close to the scraper. The effect of a 50 cm lateral iron shield around the collimator in order to reduce the radiation hazard is studied. SCRPIWIV Tntnl IrKi-k • Irnqlti in «lr - with nhlpH 1 7 i _..r ~1 n '•n. ""1 o n n i n •n «n o ł + : ID* 0 nP % 1 S 103 0 t : lot J 1 1 | 1 1 Enrrgy in Cr-V Fi(;nr(' G: Smitiiu"! Irnck trni;ih ipwifn in :ill v--liiiif-sr-<•itr.* 293 References: [1{ Arnio P. A., Lirulgren J., Rnnft J., Fas so A., Stevenson G.R., "FLUKA86 User's Guide; roin.Mits to tlić FLUKA86 Program (FLUKA87)", CERN Divisional Reports TIS-RP/168 and TIS-RP/190 (1987). [2] The LHC Study Group, "Design Study of the Large Hadron Collider (LHC), Chapter 9: Protection against Beam Losses", CERN Report 91-03 (1991). [3] Ranft J,, Ferrari A.,Sr.la P., Fasso A., Stevenson G.R., Zazula J.M., "A Comparison of Simulations Using the FLUKA-N Cascade Code with Neutron Measurements in Iron and Lead Heam Dumps Irradiated by Hadrons at 200 GeV/c and 24 GeV/c", CERN Divisional Report T1S-RP/91 (1991). [4] Stevenson G.R., Thomas R.H. (eds.) "Radiological considerations for the environment nmund the. LHC.", CERN Divisional Report CERN-TIS/89-19 (LHC Note 115) (1989). LIST OF PUBLICATIONS: I. Articles: 1. J. Livsa, I. Śliwka, B. Drozdowicz, Hypercoulometric effect in an electron capture detector polarized with an additional voltage, Chromatography, Vol. 32, No 5/6 (1991) 248. 2. K. Drozdowicz, M. Hoek and D. Aronsson, Energy calibration of neutron detectors for the neutron spectromctr "TANSY", Nucl. Instr. Meth. in Phycics Research, A306 (1991) 315. 3. J. A. Czubek, K. Drozdowicz, B. Gaoaiiska, A. Igielski, E. Krynicka-Drozdowicz and U. Woźnicka , Advances in absolute determination of the rock matrix absorption cross- section for thermal neutrons, Acta Geophysica Polonica, Vol. 39 No 1 (1991) 97. 'I. J. A. Czubek, K. Drozdowicz, B. Gabańska, A. Igielski, E. Krynicka-Drozdowicz and U. Woźnicka, Advances in absolute determination of the rock matrix absorption cross- section for thermal neutrons, Nucl. Geophys., Vol.5 No 1/2 (1991) 101. 5. H. J. Mohring, K. Noack, J.M. Zazula, Estimation of the neutron field around the HERA proton beam dump, Nucl. Instr. and Meth., A300 (1991) 188. 6. D. Dworak, J. Loskiewicz, A comparison of muligroup neutron cross-section obtained from the ENDF/B-IV library with the Abagyan - Bondarenko (ABNC) library as used in geophysical calculations, Nucl. Geophys., 5 (1991) 1. 7. T. Cywicka-Jakiel, I. Hajdas, J. Loskiewicz, Statistical comparison of potential precision of instrumental methods of coals calorific value measurement, Górnictwo, 15 (1991) 13. 8. J.M. Zazula, K. Tesch, Study of the neutron field from a hadronic cascade in iron: varification of a Monte Carlo calculational model by comparison with measured data, Nud.Instr.and Meth., A300 9. K. Tesch, J.M. Zazula, Shielding properties of iron at high energy proton accelerators studied by a Monte Carlo code, Nucl.Instr.and Meth., A300 (1991) 179. 10. P. Maloszewski, A. Zuber, Influence of matrix diffusion and exchange reactions on radio- carbon ages in fissured carbonate rocks, Water Resour. Res., 27 (1991), 1937-1945. 294 1L. P. Maloszewski, A. Zuber, Comment on "A new coupling term for dual-porosity models" by R.C.Dykhuizen, Water Resour. Res., 27 (1991), 2151-2152. 12. A. Zuber, J. Grabczak. Współczesne problemy hydrogeologii. Wyd. SGGW-AR, Warszawa 1991, 202-207. 13. J. Grabczak, J. Motyka, A. Zuber. Współczesne problemy hydrogeologii. Wyd. SGGW- AR, Warszawa 1991, s. 305-307. 14. A. Zuber. Ochrona wód podziemnych w Polsce. Stan i kierunki badań. Publ. CPBP 04.10, Zesz. 56, Wyd. SGGW-AR, Warszawa 1991, s. 237-250. 15. J. Motyka, A. Zr.ber. Geologiczne aspekty ochrony środowiska. Wyd. AGH, Kraków 1991, s. 240-244. 16. A. Zuber, J. Grabczak. Budowa geologiczna, warunki hydrogeologiczne i geotechniczne podłoża Krakowa. Wyd. AGH, Kraków 1991, s. 51-58. II. Reports: 1. J. Lasa, Greenhouse effect, INP Report No 1542/AP (1991), Kraków. 2. J. Lasa, Earth's ozone layer, INP Report No 1548/AP (1991), Krakow. 3. J. Lasa, Gaia hypotesis.INT Report No 253/PS (1991), Kraków. 4. G. Grosshoeg, D. Aronsson, K. Drozdowicz, M. Hoek, R. Rydz, L. Norberg and L. Urholm, User manual for TANSY-KM5, Report CTH-RF-82 (1991), Chalmers University of Tech- nology, Goteborg. 5. E. Krynicka, Correlation of the sample absorption and the time decay of thermal neutrons in a bounded sample-moderator system, INP Report No 1541/AP (1991), Krakow. f>. J. S.vakon, T. Cywicka-Jakiel, E. Drozdowicz, B. Gabańska, J. Łoskiewicz, U. Woźnicka, The correlaions between the concentrations of natural radiation elements (K, U, Th) and thermal neutron absorption cross-section value (S ) for Carpatian rock, INP Report No 1535/AP (1991), Kraków. 7. U. Woźnicka, Time-dependent thermal neutron field in two-region bounded systems, Re- port CTH-RF-87 (1991), Chalmers University of Technology, Góteborg. 8. J. Bogacz, J. Łoskiewicz, J. M. Zazula, Applying the universal neutron transport codes to the calculation of well-logging probe response at different rock porosities, INP Report No 1547/AP (1991), Krakow. 9. J. Łoskiewicz, J.M. Zazula, Optimization of neutron flux estimation methodes in the Morse code as used in nuclear geophysics, INP Report No 1544/AP (991), Krakow. 10. J. Łoskiewicz, T. Cywicka-Jakiel, G. Tracz, Computer assessment of the influence of hu- midity and ash content changes in Polish coals on their calorific value as measured using neutron inelastic scattering, INP Report No 1562/AP (1991), Kraków. 11. G. R. Stevenson, J.M. Zazula, Radiation doses and secondary neutron fluxes expected in the low-beta quadrupoles following the LHC interaction region, CERN Div. rep. TIS- RP/IR/91-23, (1991). 295 12. G. R. Stevenson, J.M. Zazula, Radiation levels in the LHC tunnel due to halo protons lost on an LHC beam scraper, CERN Div. rep. TIS-RP/IR/91-20, (1091). LECTURES AND COURSES: 1. In 1991 (April and May) the special training course sponsored by the International Atomic Energy Agency was held by Professor Czubek in the People's Democratic Republic of Korea during two months. The subject was the calibration of tools, logging practice and interpretation of ganima-ray (and other) logging results for uranium exploration. 34 hours of lectures, 51 hours of practical works and one week of field works have been carried out by Professor Czubek. The entire work was focused towards the application of the STRATALOG (Trade Mark of Australia) logging equipment. The theory of calibration of gamma ray logging tools, theory of gamma ray logs, theory of interpretation of gamma ray logs and advanced theory of interpretation of gamma ray logs (deconvolution problems in presence of random noise) have been presented during the course. 2. Professor J. Loskiewica was lecturing Physics (one semester, 2h/week) and Instrumental Analysis (one semester lh/week) for Commodity Science students at Cracow School of Economics. LIST OF SEMINARS: 1. J. Swakoń - The correlations between the concentrations of natural radioactiv elements (K, U, Th) and thermal neutron absorption cross-sections value. 2. G. Tracz - Sulphur in coal. 3. K. Drozdovvicz - Energy calibration of neutron detectors. 4. J. Swakoń - Analysis of concentrations of elements of rare earths in minerals. 5. G. Tracz - Dienergctic measurements of the ash content in the coal (on the tape). 6. J.A. Czubek - Geophysicist's impression from North Korea. 7. J. Łoskiewicz - Working out of data and the neuron network. EXTERNAL SEMINARS AND CONFERENCES: 1. On July 15 to July 19 Professor Czubek took part in a Consultant Meeting of the IAEA organized at the Schlumberger-Doll Research Center at Ridgefield, Conn., USA. 2. On July 22 to July 24 Professor Czubek stayed with SDR in Ridgefield, where he gave a general lecture: R h D in Nuclear Geophysics at the Institute of Nuclear Physics. 3. On 22 to 24 of October 1991 a meeting at the borehole logging center at Zielona Góra was held on problems of neutron tool calibrations. Professor Czubek presented there the 2-day seminar on the semi-theoretical way of calibration of neutron porosiiy tools. 296 4. On 28 to 29 Novemher 1991 at the 3-rd Polish Symposium on "Application of geophysics in mining of raw materials" held in Jaworze, Professor Czubek was a chairmen of Nuclear Geophysics session. 5. J. Lasa, 8th Danube Symposium on Chromatography. September 2-6, 1991, Warsaw, (member of organisation committee). 6. J.Lasa: "Gaiahypothesis". The conference: Geochemical, hydrocliemicaland biochemical variation of environment, Cracow, December 2, 1991. 7. J. Lasa, I. Śliwka, B. Drozdowicz, A.Korus: "Measurements of the chloric compounds round about Pharmacy Industrial Works "Polfa" in Cracow". The conference: Geochemi- cal, hydrochemical and biochemical variation of environment, Cracow, December 2, 1991. 8. A. Zuber: "The strategy of protection of environment from industrial pollution in Poland". The conference: Geochemical, hydrochemical and biochemical variation of environment, Cracow, December 2, 1991. 9. U. Woźnicka: "Measurement of the thermal neutron macroscopic absorption cross section on small rock samples". Research Co-ordination Meeting of the IAEA's Co-ordinated Research Programme on "Nuclear Borehole Logging Techniques in Exploration and Ex- ploitation of Natural Resources" Debrecen, Hungary, April 15-19, 1991. 10. K. Drozdowicz: "Thermal neutron scattering kernel for hydrogenous media". CTH-RF Seminar, Goteborg, November 14, 1991. 11. J. Swakoń, "Correlations between concentrations of natural y-radiating elements and neu- tron absorption cross section values of samples from Karpatian Mountains". Conference on applications of geophysical methods in solid fossil materials mining. Jaworze, November 1991. 12. Program for numerical analysis of natural 7-radiation spectra and its application toK,U,Th concentrations correlation with neutron absorption cross section values. IFT J AGH Krakow. GUESTS HOSTED BY THE DEPARTMENT: Dr R.M. Mani, Head of Industrial Applications and Chemistry Section IAEA, Wienna. 297 , V '* [ Department of Nuclear /I Radiospectroscopy j : r:- 1. FOREWORD The research at the Department of Nuclear Radiospectroscopy of the H.Niewodnicza- ński Institute of Nuclear Physics concerns various problems of nuclear magnetic resonance (NMR) and its applications in different areas of science with molecular dynamics in the first place. The current research program can in principle be divided into the following main directions. 1) Investigation of quantum and classical rotations of ammonium ion and methyl group in crystals as inferred from NMR spectroscopy protons and deuterons NMR spectroscopy. A theory has been developed explaining a variety of NMR spectra found in different crystals at different temperatures and magnetic fields. Tunneling frequencies and reorientation rates have been evaluated from the spectra in some cases. 2) Zero-Field NMR. Development cf measurement techniques and application to the problem of molecular motion in solids. Theoretical investigations concern averaging of a given spin interaction by means of a specially designed pulse sequence. 3) Computer simulation of different crystal models with incommensurate phases, glassy properties and of high T superconductors. The model with incommensurate phases has allowed to simulate the soft mode and the phase and amplitudon modes, which are characteristic features of incommensurate phases, and to confirm the stripple nucle- ation mechanism of the phase transitions. It has been shown that the commensurate- incommensurate phase transition is described by the cascade mechanism and the incommensurate-commensurate transition by a serial mechanism. The same simu- lation technique has been applied to the model of high T superconductor YBa Cu O in order to show the anisotropy of fluctuations and growth of microstructure during annealing. It appears that the first stage of annealing is a quild-like microstructure, which later becomes a strip domain structure. 4) Magnetic Resonance Imaging. Research are carried out on the development of new techniques of magnetic resonance imaging (MRI), localised magnetic resonance spec- troscopy (MRS) and magnetic resonance microscopy, gradient coils design, instrumen- 299 tation for MRI and MRS, and application of these techniques to biomedical research. Special software system MARIS-PC for MRI and MRS have been developed. In vivo biomedical research are carried out with the Institute for Biological Sciences, National Research Council in Ottawa, Canada and concentrate on MRI and MRS studies of the mechanism of brain stroke in rat and heart ischemia in pig animal model. The Department is equiped with a 1.5T, 6cm gap electromagnet, 6.4T superconducting magnet, an XP4-100 Bruker spectrometer, a home-made 25.5MHz microimaging system and a home-made Zero-Field NMR spectrometer of original design allowing the work at helium temperatures. The Department has a close cooperation with the NMR group of Prof.J.S.Blicharski from the Department of Physics, Jagiellonian University of Cracow. Head of Department prof, dr hab. Jacek W. Hennel 300 2. STAFF Permanent staff Artur BIRCZYNSKI Jerzy BLICHARSKI * Jacelł W. HENNEL Head of Department Andrzej JASIŃSKI Head of MRI Group Piotr KULINOWSKI Stanisław KWIEClŃSKI Zdzisław LALOWICZ Zbigniew OLEJNICZAK Krzysztof PARLIŃSKI Stanisław SA GNOWSKI Robert SERAFIN Zenon SUŁEK Krzysztof SZYBIŃSKI Bogusław TOMANEK Józef TRZASKA Andrzej URBAŃSKI Graduate students Franciszek HENNEL Małgorzata SZAYNA also at the Institute of Physics, Jagiellonian University, Consultant 301 Phase Transitions in Incommensurate Phases K. Parlinski, F.Denoyer1 and G.Eckold2 1 Laboratoire dt Physique des Soiides, University Paris-Sttd, 91Ą09 Orsay, France 2Institut fur Festkorperforschung, KFA, 5170 Jiilich, Germany In a number of dielectric crystals a long-range static and periodic modulation of some degree of freedom, which wavelenght persists incommensurate with the lattice constant of the undelying ordinary crystal, has been discovered [1], Such a modulation can propagate in one, two or three directions, but the most studied are the one-dimensionally modulated systems. They can be visualized as a sequence of parallel and equidistant domain walls called discommensuration planes, which separate slides of domains. The wave vector of the periodic modulation can be precisely measured by r-ray and neutron diffraction methods. One well-known example is the thiourea (SC(NDj)2) -crystal [2], in which the orientations of thoiurea molecules from a static and a periodic one-dimensional wave, directed along the high-symmetry axis of the orthorhombic lattice. Another example is the crystal of biphenyl. The biphenyl molecule is build up from two benzene rings. In the incommensurate phase the twist angle between the two benzene rings of a single molecule changes from unit cell to unit cell, forming a static and periodic one-dimetisional incommensurate modulation [3,4). In incommensurate crystals the characteristic wave vector of the modulation changes as a function of temperature. These changes are the consequences of the crystal-lattice reconstruction. It has been believed that in crystals with one-dimensional modulation the reconstruction occurs via the slrip-plc mechanism [5,6,7]. A stripple is a topological defect build up from few domains separated by the dis- commensuration planes, which are bounded by a closed curve called dislocation (or deperiodization) line. The form of a stripple resembles a disc. In a superheated or undercooled crystal a stripple is nucleated by thermal fluctuations. Later it grows by lateral motion of the dislocation line adding to the system one period of the modulation. The purpose of the present work was to use the molecular-dynamic technique [8,9,10] and to simulate for the first time the behaviour of a three-dimensional model crystal, which shows stable one-dimensional incommensurate modulations. The results have been published in Ref. [11] and they demonstrate the existence of stripples, visualize their propagation and analyze the structure of stripples. We could also relate Jie temperature anomalies to the stripple nucleation processes. Fig.l Maps of the particle displacements in the kinetic run of the tetragonal model, demonstrating the nucleation Y and growth of the stripple. Upper and lower maps are sections which are perpen- dicular and parallel, respec- tively, to the modulation di- rection. Maps (a), (b) and (c) correspond to subsequent mo- ments of time. The proposed model was a three-dimensional simple tetragonal lattice with one particle per unit cell and each particle had one displacive degree of freedom. The particles were interacting via potential energy 302 which garnntied the stability of the incommensurate modulation. The simulated crystallite consisted of 40 x 40 x 60 = 9(3000 unit cells. The dynamical behaviour of the system was traced by iterating in time the Newtonian equations of motion for all particleR. In order to remove the surface effects, periodic boundary conditions were used. The model allows to study static and kinetic processes. By changing the potential parameters, the system could be transfered from a stable state with one modulation wave vector to a state with another wave vector. In this way we were able to produce topological defects - stripples - which are necessery for reconstruction of the incommensurate modulation. Fig. 1 shows a series of maps of particle displacements on the XZ and XY sections of the simulated crystallite, where Z is the direction of the modulation. The maps are the result of our computer simulation. Dark and white regions correspond to large and small particle displacements, which in this case are the domains and discommensuration planes or dislocation lines, respectively. The maps XZ consist of incommensurate and commensurate regions seen in the upper and lower parts, respectively. On the map (a), one notices the moment of stripple nucleation. This strlpple grows in lateral directions, what is seen in maps (b) and (c). The XY maps visualize the stripple evolution in planes perpendicular to the modulation direction and lay at the level indicated by the side marks on the XZ maps. The circles represent the dislocation lines. The peculiarity of the incommensurate crystal is that one stripple adds to the system only one new period, and therefore, it changes the modulation wave vector by a negligible quantity l/N2, where Nz is the size of a crystal along the modulation direction. Hence, to transform a macroscopic crystal from one wave vector modulation to another one a large number of stripples is needed. Careful experiments made on thiourea doped with 3% of urea [12] and on quartz [13], have indicated that, under extreemly slow heating conditions the dielectric constant and the birefringence, respectively, show anomalies, which indicate that about iO3 stripples appears in the crystal at once. Then, one irnmendiately asks the question whether the nucleation of thausend of stripples is independent or correlated? We have attemted to answer this question performing a molecular-dynamics simulation of a simple three-dimensional model of the size of 30 x 30 x 180 = 1C2000 unit cells [14]. We have discovered that the metastable incommensurate phase, which requires few stripples in order to relax to an equilibrium state, produces all these stripples in a short time interval and in one randomly chosen layer of the crystal being perpendicular to the modulation direction. This process we call a serial nucleation of stripples. The degree of metastability and consequently the number of produced stripples depends on the imposed boundary conditions. The necessery condition for the serial nuclcation process is that the incommensurate modulation is pinned at the suifaces of the crystal being perpendicular to the modulation direction. That requirement prevents the nodes of the modulation to shift so that they cannot leave the crystal through the mentioned surfaces. In real crystal the role of these surfaces can play grain boundaries, precipitates of impurities, etc. References [1] see Incommensurate Phases in Dielectrics, edited by ll.Blinc and A.P Levanyuk, Vol. 14 of Modern Problems in Condensed Matter Sciences (North-Holland, Amsterdam, 1986). (2] K.Parlinski and K.H.Midiel, Phys.Rev. B 29, 396 (1984); K.Parlinski, Phys.Rev. B 20, 410 (1984). [3] N.M.Plakida, V.A.Bieluslikin, I.Natkaniec and T.Wasiutynski, Phys. Status Solidi B 118, 129 (1983). [4] K.Parlinski. W.Schranz and H.Kabelka, Phys.Rev.B 39, 488 (1989). [5] V.Janovec, Phys.Lctters, 09, 384 (1983). [6] K.Kawasaki, J.Phys. C 10, 6911 (1983). [7] K.Parlinski, Comp.Phys.Rep. 8, 153 (1988). [8] K.Parlinski, Phys.Rev. B 35, 8680 (1987). [9] K.Parlinski, Phys.Rcv. B 39, 12154 (1989). [10] K.Parlinski, Ferroelectric 104, 73 (1989). [11] K.Parlinski, F.Denoyer and G.Eckold, Phys.Rev. B 43, 8411 (1991). [12] A.Ouodera, F.Denoyer, J.Godard and M.Lambert, J.Phys. France 49, 2065 (1988). [13] F.Mogcon, G.Dolino and M.Valladc, Pliys.Rev.Lett. 02, 179 (1989) [14] K.Parlinski'aiul F.Diinoyer Phys.Rev. B 41, 11428 (1990). 303 Scaling and Time Reversal of Spin Couplings in Zero-Field NMR A.Llor, Z.Olejniczak, J.Sachlcben, A.Pines A general theory of coherent isotropic averaging in Nuclear Magnetic Resonance was de- veloped. In zero external field, magnetic field pulses can selectively average the internal spin Hamiltonians, while preserving the intrinsic invariance of the NMR spectrum with respect to crystallite orientation. The theory predicts the limits of the scaling factors as a function of the rank of spin interactions. Time reversal is possible ior irst- and second- rank tensors with optimum scaling factors of -1/3 and -1/5 respectively. The coherent averaging pulse sequences were designed, based on cubic and icosahedral symmetry. The first observation of spin echoes in Zero-Field NMR was reported, resulting from the time reversal of isotropic many-body spin couplings. The introduction of time-reversal schemes makes it possible to develop a zero-field analog of the high-field multiple-quantum NMR spectroscopy. [1] A.Llor, Z.Olejniczak, J.Sachleben, and A.Pines, Phys.Rev.Lett. 67, 1989 (1991). [2] A.Llor, Z.Olejniczak, and A.Pines, submitted to Phys.Rev.B. 250 500 1000 Time (microseconds) FIG. Isotropic zero-field echoes in polycrystalline adamantane: A) the magnetization of protons decays due to the local dipole-dipole interactions; B) after 74fxs the isotropic time reversal sequence is applied and the magnetization is refocused 370fJ.s later, because the scaling factor is -1/5; C) a free evolution in zero field is resumed at 810/tz.s, resulting in a second echo at a time 304 O i — Echo-planar Imaging in q-space i 'a b F. HENNEL Institute of Physics, Jagicllonian University, 30-059 Kraków, Poland Z. SULEK and A. JASIŃSKI Insiilute of Nuclear Physics, Kraków, Poland The aim of dynamic NMR imaging (q-spacc imaging) (1) is to measure the density function r(r,v) which describes the distribution of positions and velocities of the spins. The experiment involves scanning the reciprocal space based on vectors k and q, which arc conjugate to position and velocity, respectively. Conventionally, each q-point needs a repetition of a k-space scanning sequence, what is a time-consuming procedure. It is possible to shorten the experiment using ideas developed for the ordinary, static imaging. The presented method, echo-planar imaging in q-spacc (EPIQ) is a variant of the p-pulsed EPI (2), in which single gradient blips have been changed to pairs of compensated pulses. One dimension in k and one in q are scanned using a single spin- echo train. The acquisition time for a 64x64 image is of the order of 0.5 sec. Since the experiment is two-dimensional only, the resulting image gives a projection of the velocity distribution. However, for symmetrical objects the flow profile can be clearly determined. A results with water phantoms is presented. References 1. P.T. Callaghan, CD. Eccles and Y. Xia J.Phys.E 21, 820 (1988) 2. D.N. Guilfoylc, R.J. Ordidge and P.Mansficld SMRM 1989 p.829 An EPIQ image of water in a glass tube of 10 mm diameter representing spin density on the (x,vz) plane (velocity on the vertical axis). A parabolic flow profile, expected for Newtonian liqiuds, is visible. Time of a single acquisition was 600 ms. 305 SHIELDED GRADIENT COILS AND RADIO FREQUENCY PROBES FOR HIGH RESOLUTION IMAGING OF RAT BRAIN Andrzej Jasinskl, Tomasz Jakubowski, Marek Rydzy, Paul Morris , Ian C.P. Smith2, Piotr Kozlowski, and John K. Saunders2 Institute of Nuclear Physics, 31-342 Krakow, Poland Morris Instruments Inc., Glouster, Ontario, Canada Institute for Biological Sciences, National Research Council of Canada, Ottawa, Canada A shielded gradient system and radio frequency probes for 4.7T 30 cm horizontal bore magnet were developed. The systems were designed principally to obtain images and localized spectra from rat brains. The gradients consist of the main gradient coils of classical design and shielding colls cancelling out the external magnetic field. The gradients can operate in either shielded or non-shielded mode. The rf probe which combines both highest sensitivity and highedt resolution, consists of a large modified saddle type transmitter and a small surface reception coil, actively decoupled using diodes. The system performance is demonstrated in Fig. 1, where shielding efficiency is shown, and on phantoms and on a rat brain, where an Image with inplane resolution of 80 microns and a slice thickness of ISO microns is obtained. This paper has been accepted for publication in Magnetic Resonance in Medicine. _A A A. Fig. 1. NMR spectra of a spherical water phantom of 23 mm I.D. for the gradient coils In shielded and unshielded mode. Spectra from the bottom correspond to: a reference (no gradient), unshielded and shielded recorded 1 msec, the same 5 msec after the end of 1 G/cm gradient pulse 100 msec long. 306 MAGNETIC RESONANCE IMAGING OF CARBON IMPLANTS IN THE RABBIT CONDYLE OF THE FEMUR Bogusław Tomanck, Stanisław Sagnowski, Stanisław Kwicciński, Andrzej Jasiński, Institute of Nuclear Physics, Kraków, Poland Emil Staszków, Żeromski Hospital, Kraków, Poland Tlie replacement of the broken bone by the carbon-carbon composites gives rise to the ingrowth of surrounding tissues into the artificial material (1). Although the carbon element is invisible to the proton MRI, the tissue surrounding it can easily be seen in this method, thus allowing to study the effects of the carbon implants on the tissues. Moreover, the observation of the gradual ingrowth of the tissue in carbon implant is also possible. The carbon-carbon composite screws which are well tolerated by the tissue were used to investigate ostcosynthesis of the broken bone (2). Ten adult male rabbits were subjected to an identical surgical operation. The knee of an anesthetized rabbit was experimentally exposed. The condyle of the femur was cut across and then it was ostcosynthesiscd with the carbon-carbon composite screw. After suturing of the surgical wound the knee joint was immobilized in the plaster cast for two weeks. The animals were killed at 4, 6, 8, 10 and 12 weeks after operation. The condyle of the femur with the implant was excised and used for MRI examinations. The NMR images were obtained on home made 25 MHz protor imaging system, The gaussian selective pulse was used to get 2mm-thick slice. 20 accumulations with 450ms repetition time were acquired for each image. The cross-section of the sample cut 8 weeks after operation from the condyle of the femur of the rabbit knee joint is shown in the Fig.l. The carbon-carbon screw is visible as a white field on the lower part of the image. The edges of the implant are not very sharp because of the tissue ingrowth into the carbon-carbon composite bulk. This effect is seen more clearly in Fig.2, where a cross-section of the sample dissected 12 weeks after operation from the rabbit knee joint is shown. Tlie black points representing the signal from the bone tissue "penetrating" the carbon material, can be seen even in the inner part of the implemented carbon screw. The dilution of the screw edges is more pronounced in this case. This work has been submitted for publication in "Magnetic Resonance Microscopy, Methods and Applications in Materials Science and Biomedicine" VCH, Weinheim. tri if if Fig. 1. Fig. 2. [1.] N.More,' GBaquey, X.Barthc, Biomaterials 9, 328 (1988). [2.] E.Staszków, Ph.D. Thesis (in Polish) (1991). 307 4. LIST OF RECENT PUBLICATIONS [1] L.P. Ingman, E.E Koivula, Z.T. Lalowicz, M. Punkinnen, E.E. Ylinen: 2H-NMR Study of Ammonium Ion Rotational Tunneling and lleorientation in (ND^SnClg Single Crystal, Z. Phys. B - Condensed Matter, 81, 175, (1990) [2] P.G. Morris, H.E. Darceuil, A. Jasiński, A.K. Jha, D.J.O. Mclntyre and D.H. North- cote: NMR Microscopy of the Germinating Castor Bean, Phil. Trans. R. Soc. Lond., A 333, 487, (1990) [3] Z.T. Lalowicz, S.F. Sagnowski: Multiaxial Reorientation of ND^ Ions Studied by 2H-NMR Spectroxcopy, Z. Naturach., 46a, 829, (1991) [4] K. Parliński, F. Denoyer and G. Eckold: Molecular-Dynamics Study of Incommensu- rate Phases in Three-Dimensional Crystal, Phys. Rev., B 43, 8411, (1991) [5] H. Grimm, E. Courtens and K. Parliński: Two-Step Freezing Process in the Mixed Crystal RADP, J. Non-Crystailine Solids., 131 - 133, 76, (1991) [6] E. Salje , K. Parliński : Microstructure in High Tc Superconductors, Supercond. Sci. Technol., 4, 93, (1991) [7] G.R.Sutherland, J. Peeling, H.J. Lesiuk, R.M. Brownstone, M. Rydzy, J.K. Saunders and J.Ej. Geiger: The Effects of Caffeine on hchemic Neuronal Injury as Determined by Magnetic Resonance Imaging and Histopathology, Neurosciences, 42, 171, (1991) [8] A. Jasiński, P. Kozlowski, A. Urbański and J.K. Saunders: Hexagonal Surface Gradi- ent Coil for Localized MRS of the Heart, Mag.Res.Med., 21, 296, (1991) [9] A. Llor, Z. Olejniczak, S. Sachleben and A. Pines: Scaling and Time Reversal of Spin Couplings in Zero-Field NMR, Phys.Rev.Lett., 67, 1989, (1991) 308 5. INTERNAL SEMINARS 14.02.1991 Mgr Bogusław TOMANEK, NMR Probe with Short Decay Time; 21.02.1991 Mgr Franciszek HENNEL, Removal of Quadrature Detection Imperfections; 28.03.1991 Prof. Dr W. MULLER-WARMUTH, University of Miinster, MAS - NMR Studies of Molten and Sol-Gel-Derived Glasses; 23.04.1991 Dr J. MUSZYŃSKA, Dr Z.KONOPACKA, Institute of Apiculture in Puławy, Possible Application of NMR Tomography in Apiculture; 16.05.1991 Mgr Andrzej URBAŃSKI, Introduction to MS-Windows and MS-Word; 29.05.1991 Mgr Stanisław KWIECINSKI, Introduction to Grapher and Surfer; 15.06.1991 Mgr Andrzej URBAŃSKI, Gradient Surface Coil for NMR Imaging; 27.06.1991 Dr Artur BIRCZYŃSKI, Investigations of Internal Rotations in p-nitroaniline as In- ferred from Deuteron NMR; 4.07.1991 Mgr Stanisław KWIECINSKI, Electronic Mail - Part I; 11.07.1991 Mgr Stanisław KWIECINSKI, Electronic Mail - Part II; 12.09.1991 Dr Zbigniew OLEJNICZAK, Time Reversal in Zero-Field NMR; 3.10.1991 Dr Z.SUŁEK, mgr F.HENNEL, mgr S.KWIECIŃSKI, mgr A.URBAŃSKI, Report from the 1st International Conference on NMR Microscopy, Heidelberg 13-16.09.1991; 25.10.1991 Dr Artur BIRCZYŃSKI, Composite f pulse for Measurement of Deuteron Ti in Solids; 31.10.1991 Mgr Robert SERAFIN, Theory of Pulse Effects on Spin Systems - part I; 7.11.1991 Mgr Franciszek HENNEL, EPIQ - Imaging of Flow Velocity; 14.11.1991 Mgr Robert SERAFIN, Theory of Pulse Effects on Spin Systems - part II; 6. ORGANIZED CONFERENCES XXIV Seminar on NMR and Its Applications, Kraków, 2-3 December, 1991 309 7. TALKS GIVEN AT OTHER CONFERENCES AND IN OTHER LABORATORIES 1. K.Parlinski, Molecular-Dynamics Study of the High Tc Superconductor, Department of Statistical Physics, Jagiellonian University, Cracow. 2. K.Parlinski, MD Simulation of Elastic Phase Transition in High Tc Superconductors, Institut fiir Experimentalphysik, Universitat Wien, Wien, Austria. 3. K.Parlinski, Molecular-Dynamics Simulation of Incommensurate Phases and High Tc Superconductors, Laboratoire d'Electronique, Universite de Provance, Marseille, France. 4. K.Parlinski, Molecular-Dynamics Simulation of Commensurate-Incommensurate Phase Transitions, Radio- and Microwave Spectroscopy, RAMIS-91, 8-11 April, 1991, plenary lecture. 5. K.Parlinski, A Phase Transition in Quasicrystal Model, One-day Seminar on Statisti- cal Physics, 5 June, 1991, PAN Warsaw, oral contribution. 6. K.Parlinski, Computer Simulation of Commensurate-Incommensurate Phase Transi- tions, IV Symposium on Statistical Physics, 19-29 September, 1991, Zakopane. 7. K.Parlinski, Computer Simulation of Incommensurate Phases and Texture, Janik's friends Meeting, 23-27 September, 1991 . 8. K.Parlinski, Computer Simulation of Texture of High Tc Superconductors, III National Symposium on High Tc Superconductivity, 20-21 October, 1991, Wroclaw. 9. Z.Olejniczak, Time Reversal in Zero-Field NMR, Physics Department, Texas A&M University, College Station, Texas, USA ,15 April, 1991. 10. Z.Olejniczak, Scaling and Time Reversal in Zero-Field NMR, Max-Planck Institut fur Polymerforschung, Mainz, Germany, 18 December, 1991. 11. Z.T.Lalowicz, Ammonium Ion Motions in ND4CIO4 Studied by 2H-NMR Spectro- scopy, Symposium on Quantum Aspects of Molecular Motion in Solids, Schloss Ring- berg, Germany, 3-6 April, 1991. 310 12. Z.T.Lalowicz, S.Sagnowski, 2H-NMR Study of Multiaxial Reorientation of NDf Ions, Department of Radiospectroscopy, Jagiellonian University, Cracow, 15 June, 1991. 13. A.Birczyński, Proton and Deuteron Spectrum of ND4CIO4 Single Crystals, Depart- ment of Radiospectroscopy, Jagiellonian University, Cracow, 16 January, 1991. 14. J.W.Hennel, Applications of Zero-Field NMR to Liquid Crystals, Radio- and Mi- crowave Spectroscopy, RAMIS-91, 8-11 April, 1991, plenary lecture. 15. S.Kwieciński, Magnetic Resonance Imaging of Carbon Fibers Implants in Bones, 1st International Conference on NMR Microscopy, Heidelberg, Germany, 16-19 Septem- ber, 1991. 16. S. Kwieciński, Carbon Fibers in Medicine - NMR Imaging, Department of Radiospec- troscopy, Jagiellonian University, Cracow, 26 October 1991. 8. VISITING SCIENTISTS Prof. Dr W. MVLLER* WARMUTH, • Institute of Physical Chemistry, University of Miinster, Germany, March 1991. Dr J.KLINOWSKI, - Department of Chemistry, University of Cambridge, United Kingdom, December 1991. Dr K.BARTUSEK, - Ustav Pristrojowe Techniky CSAV, Brno, Czechoslovakia, December 1991. Dr J.SEVCOVIC, - Institute of Physics, Technical University of Kosice, Czechoslovakia, December 1991. 311 9. LECTURES AND TEACHING 1. Prof. J.W. Hennel - NMR for Postgraduate Students of Chemistry, Department of Chemistry, Jagiellonian University, Cracow, April - May 1991. 2. Prof. J.S. Blicharski - Radiospectroscopy for Physics' Students, Department of Physics, Jagiellonian University, Cracow, 1990/91. 3. Prof. J.S. Blicharski - Biophysics for Medical Physics' Students , Department of Physics, Jagiellonian University, Cracow, 1990/91. 4. Prof. J.S. Blicharski - Medical Physics' Seminar, Department of Physics, Jagiellonian University, Cracow, 1990/91. 5. Dr. A. Jasirski - NMR for Physiologists, Ottawa University, Canada, 1990/91. 10. Ph.D THESIS Artur BIRCZYŃSKI "Investigations of Tunneling and Classical Reorientation of Ammonium Ions in Am- monium Perchlorate, studied by NMR", Niewodniczański Institute of Nuclear Physics, Cracow, February 1991. 312 "V'i; Department of Nuclear Physical Chemistry r! i f s DEPARTMENT OF NUCLEAR PHYSICAL CHEMISTRY Head of the Department: Prof.dr Jan Mikulski OVERVIEW: The Department, headed by Professor Jan Mikulski, consists of three collaborating but independent Laboratories: 1. Laboratory of Physical Chemistry of Separation Processes (Head: Professor Jan Mikulski, 2 research associates (Ph.D.) 6 research assistants (M.Sc. or Eng.), 1 technician); 2. Laboratory of Chemistry and Radiochemistry (Head: dr hab. Zdzisław Szeglowski, 1 research associate (Ph.D), 1 technician); 3. Environmental Radioactivity Laboratory (Head: Mrs, Mirosława Jasińska M.Sc, 3 research assistants (M.Sc)). Two research assistants from the Laboratory of Physical Chemistry of Separation Processes as well as Head of the Laboratory of Chemistry and Radiochemistry have recently been doing research under long-term contracts in the Joint Institute of Nuclear Research in Dubna. Laboratory of Physical Chemistry of Separation Processes There are two alternative possible ways of separating radio- active isotopes from particle- bombarded targets: 1. by applying physical, usually thermal, methods, and 2. by chemical methods, involving solvent extraction, chxomatography, or extraction chro- matography. It depends on the particular application which method or combination of methods is to be chosen. The main interest of our research group is production (on the cyclotron) and separation of neutron-deficient isotopes for medical diagnosis (SPECT) or therapy. The efFort has been done to obtain preparations of isotopes fulfilling severe purity requirements of international and local Pharmacopoeias. The quality of products is being checked by means of gamma and alpha spectrometry as well as by chemical analytical methods, mainly atomic absorption spectroscopy and chromatography. The above research program branches into several others, including measurements of nuclear reaction cross-sections, band resolution techniques, preparation of radioactive sources, detec- tion of non-radioactive trace elements (e.g. in food and environment). Last but not least, an independent project on desulphurization of flue gases is also carried out in the Laboratory. 313 Laboratory of Chemistry and Radiochemistry In the Laboratory of Chemistry and Radio chemistry the systematic studies of phyaicochem- ical properties of transition elements in solutions are carried out. The studies are mainly con- cerned with the conditions of complex formation between some metals and organic as well as inorganic ligands. Stability constants of the complexes are being determined. The results of the performed experiments were used for the elaboration of new rapid and selective methods for isolating various elements. Recently, some of these results have been applied for fast and continuos procedure of separation of transactinide elements from aqueous solutions of nuclear reaction products obtained at the U-400 Cyclotron of JINR Dubna. Our studies can also be used for estimating pollution levels of natural environment. Environmental Radioactivity Laboratory Laboratory conducts continuos monitoring of radioactive contamination of atmosphere at ground level using a field station situated at the premises of the Institute. Weekly reports are being submitted to the National Atomic Agency (PAA). In collaboration with the Department of Pharmaceutical Botany of the Medical Academy in Kraków, the Forest Ecology Department of the Academy of Agriculture in Kraków and IAEA investigation of radionuclide concentration in natural envinronment, mainly in the forests, had 134 137 106 238 241 been carried out [4). The nuclides of interest were Cs, Cs, Ru, 23e+«°pu, Pu, Am, and 9QSr. Currently, measurements of concentration of 137Cs and 134Cs and 40K in mushrooms and other forest samples collected at 404 sites all around Poland during autumn of 1991, are per- formed. Measurements of natural radionuclides concentration in waste materials from T.Sendzimir Steel Works were carried out to access the influence of wastes on the environment. Concentration of natural radionuclides was measured also in several building materials produced from fly ashes by various manufactures from Southern Poland. PERSONNEL: Prof.dr Jan Mikulski — Head of the Department Research staff: Paweł Grychowski, Mirosława Jasińska, Krzysztof Kozak, Barbara Kubica, Piotr Macharski, Zbigniew Mazgaj, Jerzy W. Mietelski, Ryszard Misiak, Ewa Ochab, Barbara Petelenz, Mirosław Szalkowski, Zdzisław Szeglowski, Docent, Bogdan Was, Paweł Zagrodzki. Technical staff: Roman Fiałkowski, - part time, Jan Kwaśruk, - part time, Stanisław Moroz, - part time. 314 RESEARCH ACTIVITIES: ! (O i 6 Cross Sections for (p,X) Reactions on Ti, V, Ga and Ge at E =660 MeV J.V. Aleksandrov1, A.A. Astapov1, S.K. Vasiliev1, R.B. Ivanov1, A. Kolaczkowski, R. Misiak, M.A. Mikhailova1, A.F. Novgorodov1, T.I. Popova1, and V.P. Prikhodtseva1 1 JINR, Dubna Cross sections for (p,X) reactions on Ti, V, Ga and Ge at E =660 MeV were measured by ga:runa-ray spectroscopy technique in JINR in Dubna. Thin disc targets of 20-25.5 mm diameters and of thicknesses of 0.0430 (Ti), 0.0618 (V), 0.471 (Ga) and 0.411 (Ge) g/cmJ were irradiated with proton current of (0.66 - 1.53)-10" p cm"2 s"1 during 5-10 min. Each target was exposed 25-30 times for 1-3 months period. Gamma-rays spectra were measured without separation of products, with a delay of 1.5-6 h after exposition. The Ge(Li) detector of 50 cc. volume and resolution 2.5 keV at E = 1.3 MeV was used. The error of the detector calibration was 4% . The values of the experimentally determined cross sections are listed in Tables 1 and 2. Within the accuracy range of 20-50% they agree with values reported by Drope3ky and O'Brien Table 1. Cross section of 660 MeV protons reaction on Ti and V . Ih.rn • L> h r n w u c 11 (1 r ., ., T i 1 J. A. ;•:." J2 ' •"'o - 2. ?f. 9 47 * Cr - 0.5H2IJM TK 0.I4J (M) 0.57?<2«> 48 rr 0.077 IB) ' 'K 5.87 (15) 4.00(?5> 48V l.OSCJ) 1 1. 0(51 4?K B.75IJ5) B.ii(Sil 48 Br. 2.43(10) 4.55(18) rBNp 0.260(1!) 0.218(11) 47 Sc 2X. 1 (1 1) 10.7(5) 24 N. 1.04(7) 1.15(61 4 *Sc 29.0(12) 20.PCBI "H. 1.40(4) 0./<(50) 4 < *Sc 6.35(25) 7.57(50) 7Be 1.55(17) l.?5(17) 44 sc 15.5(11) B.21(57) 315 Table 2. Cross section of 660 MeV protons reaction on Gft and Ge tr < Air 1 .« h a r n «.- (Ac'. »i' ar n M IK 1 1 ii G 6 Ilu. 1 id i' ... (., J! * ,, ;; 1. liifi 41Co ... 4 4 (•/;. > 1 . 94 MS' 1. :-4 cj7i *°r» H' .HIV) ' .1 ' <".*.! 71 5n «s - 2. 01(1?) c :>i . 1 < 1 III IP. '.' '..' 1 /5 li« 5. 7 14) i (• .0 (V) 1 ','.II XI A *f.e • IV . M2VI Ł*Co 4. *'.' C/li :•. 16 (141 *"(ip - 10 .0 122) 'J:' t a 0. 75 C.) 0. d HVCOI 1 1 .51171 MHn )4 . 7. (7 ) 11. ? l!il "t,i 1. 14 I! 11 U .1(7) 5?Mn 4 .;u i vi 14 I 1 M 8 * (.f 56. 1 Co! 71 . 7 I.' 51 :?1Cr 1? .B(7) f. Ul»l 4B "o, ?'j. JII01 27 .7(11) u 4. 16 (;• 11 S " (10 1 41),. ?.1(7) 1 1. 4 "in - 0 .67(77i 'si 1. i « ( 7 1 1. 04 <«> "**n 1.0/(4 1 "''Or OHM' 1 vr> 11 o) "*7n S.S1 6 *7n t. i /1 r< i 1. 7H(IP> •* "s' V. /till) 0 7:. u.' i 4 '. "c :.. M (m t. 29(16' K 0 4 S 1 1 n 1 0 : (• 41 A > M *'. c« 7 . » 4 ( J 1 > I. 0 tl / ( / '• i 0. t.1. (.'I 5 'm .105 112) 0. 40;(i/i ?<>.• < MD '''if 2. IMIJ1 ?. 1? (V) 'tip 1 . 4 •••'U 0 . 0 ' 7 ': 7) References [lj B.J.Dropesky, H.A.O'Brien- LA-5120-PR, Los Alamos Scientific Laboratory (1972) 8. Determination of the Temperature Dependence of Yield of 211 At Isolation from the Alpha-activated Bi2O3 Z. Mazgaj and J. Mikulski The compounds labelled with 2UAt are applied in endotherapy of tumours of eyeball. In the Department of Physical Nuclear Chemistry of INP, experiments on preparation of astatine have been undertaken. The target containing 100 mg/cm2 of melted B12O3 have been irradiated on the U-120 cyclotron with alpha particles at the energy range of 25-27 MeV and the beam current of 3 ^ A. The time of exposition was about 30 mins. The yield of the 2OPBi(a,2n)211At reaction under the above irradiation conditions is ca. 3MBq//iAh. The preparation of 2nAt 212 (ti/2=7.2h) is not contaminated by other astatine isotopes - At (t1y2=0.3s) created in the (Q ,n) reaction deacays completely, and the energy threshold of the (or ,3n) reaction leading to formation of 210At is higher than 27MeV. 316 Astatine has been separated from the target material by the thermal method, using a special quartz apparatus (Fig. 1), at the temperature range of 400 - 900 "C and the air flow of 100 tnl/min. Duration of the separation process was 30 mins. 2nAt has been identified by its 76.9 and 79.3 keV lines in the X-ray spectrum and 5.86 MeV and 7.42 MeV peaks in the alpha spectrum (Fig.2 and Fig.3). The dependence of the separation yield on the temperature has been determined by comparing the spectra of the "hot target" with those of the sample after separation. The results, estimated with the accuracy of 15% are shown in Fig.4. , '* M (I ** U Electro-Absorption Spectrum of Tetracene - High Field Measurements on Polycrystalline Samples J. Kalinowski1, W. Stampor1, P. Petelenz2 and B. Petelenz 1 Technical University, Gdańsk 2 Jagellonian University, Cracow Electro-modulation spectroscopy is the main (if not the only) experimental tool to probe the properties of individual charge transfer (CT) states of polyacene crystals. Yet, a completely plausible theoretical interpretation of the classic electro-absorption experiments [1], [2] is still missing. To compare with the spectra of amorphous films of tetracene [1], we present the spectrum of a polycrystalline film. In order to offset the effect of the poorer sensitivity of our apparatus we apply a much higher electric field. The high energy part of the spectrum (Fig.l) has been numerically resolved using the pro- cedure described in Refs. [4],[5] into a superposition of the first derivative of the absorption 317 spectrum (due to the second order Stark effect) and of the second derivatives of a number of Gaussian bands, corresponding to the CT states and their vibronic satellites.. A,cm 200 100 -100 -200 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 ENERGY, aV Figure 1: High energy part of the electro-absorption spectrum of tetracene. Thick solid line.- present experimental results (polycrystalline sample, Flab), thin solid line - band resolution, broken line - experimental results of ref.jl] (amorphous sample) The first derivative contribution is weighted by the polarizability change tfp between the ground and excited state. With the Lorentz approximation for the local electric field, the present fit yields Sp of the same order as that reported for isolated tetracene molecules [6]. The positions of most bands coincide with those obtained for an amorphous sample [l],[5], minor shifts resulting from the different intensity pattern as well from that some bands may represent more than one eigenstate of CT origin [3]. Our results suggest that polycrystalline tetracene films are not exactly epitaxial, the c' direction of the crystallites deviating from the normal to the substrate by about 2 . This con- clusion, if independently confirmed, suggests electro-absorption as a potentially useful tool in the studies of the texture of thin films. This was suggested previously in a slightly different context [7]. References [1] L.Sebastian, G.Weiser, and H.Bassler, Chem.Phys. 61 (1981} 125. [2] L.Sebastian, G.Weiser, G.Peter and H.Bassler, Chem.Phys. 75 (1983) 103. [3] P.Petelenz and M.Slawik, Chem.Phys. in press. [4] B.Petelenz, P.Petelenz, H.F.Shurvell and V.H.Smith.Jr., Chem.Phys.Lett. 133 (1987) 157. [5] B.Petelenz, P.Petelenz, H.F.Shurvell and V.H.Smith,Jr., Chem.Phys. 119 (1988) 25. [6] J.H.Meyling, P.J.Boiuids and R.W.Munn, Chem.Phys.Leil. 51 (1977) 234. [7] W.Stampor, J.Kalinowski and P.Di Marco, Chem.Phys. 134 (1989) 385. 318 Studies on a New Concept of Desulphurization of Flue Gases from Coal-Burning Heating Plants .]. Kulawik and M. Szalkowski Recently, in the Laboratory of Physical Chemistry of Separation Processes, experiments are carried out on the possibility of using the reaction between S02 and moist H2S in the process of low-waste desulphurization of flue gases from small coal/coke burning plants. The laboratory experiments on the kinetics of the reaction 2H S 2 (1) showed that at the temperature of 92-96°C and in the presence of water mist, the degree of conversion of S02 to elemental sulphur, a (S02), reaches the value of 0.9 as soon as after 60 sees from tne start of the reaction. The degree of conversion is defined as n C'a-C so7 = —p,— (2) where Co is the initial concentration of SO2 (in a continuous process - concentration of SO2 at the reaction column inlet), and C is the final concentration of SO2 (in a continuous process - concentration of SO2 at the reaction column outlet), Studies on the above reaction are aimed to designing the technological apparatus and to modifying the chemical process towards elimination of the external dosage of H2S. If the method turns out sucessful, a pilot desulphurization device shall be installed in the heating plant in the Institute and, later, in similar heating plants in the town. Cross Sections for (p,X) Reactions on Zr at E - 660 MeV J.V. Aleksandrov1, A.A. Astapov1, S.K. Vasiliev1, R.B. Ivanov1, A. Kolaczkowski, R. Misiak, M.A. Mikhailova1, A.F. Novgorodov1, T.I. Popova1 and V.P. Prikhodtseva1 1 JINR, Dubna Measurements of cross sections for (p,X) reaction on thin targets were continued. The method previously described was used. In the Table 1 are presented the experimental values of cross sections for Zn(p,X) reaction. f (Ao) . a li Wur I '. V0 7? Nh X. 50(171 U1R.. I'.61 1?) A!. I 4 . ? ( 7 ) n B97r 4 4. i (;•; i v, 24. 1 (1 1 ) 71ft.. 11.7(5) V6ir .'. ov (:•() > "», ?).1(IO) 6. "?!(.> 7f 67 V0»v .".7 1 C..-1 '|lr 1 J. 1 (3) G« P . II ( 4 ) B8 f 2t..D{lt> ?4.7 (|0) sn 1.00(15) Co 117 r 5 v 5ł.. r(??) 1 1 . V ( 4 1 *'t1n 0.V0(?) 1B "*' ?/. i (i r.) !..S< (17) g 0.10(1) 7 fl. JOt.'M ^ft, 0. IA!, (38) '»n ;•. ;> 4 (14 i 4*.4(IV) 4 . *? <19) ":'*" 319 Preparation of Very Thin Active Sources for Low-Energy Electron Spectroscopy A.F. Novgorodov1 and Bogdan Was 1 JINR, Dubna Preparation of sources for the low-energy electron spectroscopy (E < lOkeV) is a very impor- tant matter because of the essential influence of source quality on the results of measurements. The sources ought to satisfy the following conditions: a) their thickness can not exceed several angstroms; b) their chemical structure must be well known; c) they must be stable in time. Till now, in the JINR, in Dubna, sources were prepared by vacuum evaporation of elec- trolytically separated elements. However, this method has several disadvantages: a time- and effort-consuming procedure, very low yield, and the lack of knowledge of the chemical form of the source. Last year, in the Department of Radiochemistry of JINR, a new method of preparation of sources was worked out. It is based on chemical sorption of the elements onto a thin layer of organic substance. The method was used successfully for preparation of Yb-169 and Tm- 167 sources. Prom the results obtained till now it appears that the new method is simple and very effective, and the resultant sources are more stable and thinner than those obtained by evaporation in vacuum. The best conditions of chemical scrption of rare earth elements and other inetals are now being studied. It seems that the chemisorption method will replace the method of evaporation in vacuum, and will be used in other nuclear research centres, e.g. in 1NR in Reź. A \ The Electrospraying Method for the Preparation of both Thin and Thick Targets from Organic Solution Z. Szeglowski and J.S. Korotkin1 1 Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, 141980, Dubna, CIS. The electrospraying method was modified by using a PTFE cylindrical cell with a precisely machined capillary aperture and a stainless steel conical needle electrode instead of a glass capillary tube. The annular opening between the walls of the capillary aperture and needle can be control adjusted. The modified device permits spraying solution of salts of metals and other chemical coumpounds dissolved in organic solvent on metallic or metallized organic foils and on some uncovered foils. The results are well reproducible. The construction of the device is schematically presented in Fig.l. In Fig.2. the alpha spectrum of a 249Cf source prepared by the described technique is displayed. 320 ~K -P .':'. H 2000 • 100 •JO WO Fig.l. a.Construction of electro- CHANNEL NUMBER spraying device: 1 - capillary aperture, 0.3 mm; 2 - stainless steel needle electrode; 249 3 - teflon cell; Fig.2. Alpha spectrum of a Cf 4 - teflon muff; source prepared by electro- 5 - stainless steel muff; spraying of Cf solution in 6 - teflon knob; acetic acid on a platinum 7 - side window. foil. b.Electrical scheme: A - high voltage source; C - resistor 3.108 ohms; G - galvanometer; K - teflon capillary cell; P - electrosprayed solution; H - target; E - metallic electrode. Production, Chemical and Isotopic Separation of the 178 2 Long-lived Isomer ™ Hf ( T1/2 = 31 years ) Yu.Ts. Oganessian1, S.A. Karamian1, Y.P. Gangarski1, B. Górski1, B.N. Markov1, Z. Szeglowski, Ch. Briancon2, D. Ledu2, R. Meunier2, M. Hussonnois2, 0. Constantinescu1, M.I. Subbotin1 1 Laboratory of Nuclear Reactions, Joint Institute for Research, 141980 Dubna, CIS 2 Institut de Physique Nucleaire, Orsay, Prance. The 178Hf with long-lived (Ti/j = 31 y) high-spin isomeric state I" = 16+ is a challenge for new and exotic nuclear physics studies. The first experiments are described, performed in order to produce a reasonable microwsight quantity of this hafnium isomer with an isomeric to ground-state ratio as high as possible (here 0.05). The reaction 176Yb (4He,2n ) using enriched target has been studied by measuring the extraction functions and the isomeric to ground-state ratio. About 3-1014 isomeric atoms have been produced up to now in irradiations with high- intensity beams (c.a. 100 /xA) at the U-200 cyclotron in Dubna. Chemical separation methods could be checked ovnr iising about 1013 atoms of the isomer. Isotopic separation experiments 321 have been performed in Orsay and preliminary results are given for the separation efficiency. The investigation has been perfomed at the Laboratory of Nuclear Reactions, JINR. •*l The Effect of N-aliphatic Alcohols on Electrophoresis of Carbon Black Suspensions in Paraffin Oil M. Paluch1 and Z. Szeglowski 1 Department of Physical Chemistry and Electrochemistry, Faculty of Chemistry, Jagellonian University, Cracow, Poland. The studies of electrophoresis of carbon black suspension in paraffin oil was performed, as a function of the concentration of added alcohols (pentanol, hexanol, heptanol, octanol and nonanol), at constant voltage -6 kV and fixed time 30 min. Analysis of the results shows that difFerent n-aliphatic alcohols affect the electrophoresis of carbon black suspensions in the same way. Up to a concentration of 0.1 mole /I of alcohol in paraffin oil the suspension includes 20, 23 and 57% positive,negative and neutral particles, respectively. Above this concentration the amount of positive and neutral particles decreases and the amount of nagative particles increases. This is due to the process of adsorption of alcohol molecules and of its micellar aggregates on carbon black particles. Rapid Method of Continuous Isolation of Some Short Lived Transactinide Nuclides from Nuclear Reaction Products Z. Szeglowski, H. Bruchertseifer1, V.P. Domanov2, B. Gleisberg1, L.I. Guseva3, M. Hussonnois4, G.S. Tikhomirova3, I. Zvara2, Yu.Ts. Oganessian2 1 Zentralinstitut fur Isotopen- und Strahlenforschung, Leipzig, Germany . 2 Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, 141980, Dubna, CIS. 3 V.I.Vernadsky Institute of Geochemistry and Analytical Chemistry, 117979 Moscow, CIS. 4 Institut de Physique Nucleaire, Orsay, France. A method for isolation of elements 104 and 105 from the products of bombardment of 248Cm and 249Bk targets with 18O ions has been developed. The nuclear reaction products were transported a distance of 10 meters from the target to a separation device by means of a KC1 aerosol jet. The aerosol particles and the solution passed through three coupled ion exchange columns.In the first cationic column the heavy actinoids generated in the bombardment were removed from the solution. On the second anionie column elements 104 or 105 were sorbed, and on the third cationic column the decay products of a transactinoids were retained. In model experiments the decontamination factors of the Hf (104) fraction from lanthanoids and heavy actinoids in various solutions of complexing agents were determined. Values as high as 105 to 6 261 10 were achieved. The identification of 104 ( Tj/2 = 65 s) was performed by separating its 2B3 263 descendants Fm ( Ta/2 =3 d) and Es ( Ta/2= 20 d) after the desorption of the actinoids from the third column. The identification of 262105 will be performed through it descendant 254Fm ( Tj/2 = 3.2h). It has been shown that in a HF solution element 104 forms stable anionie complexes which are sorbed on the anion exchange resin and are similar to such complexes of Zr and Hf. Thus element 104 behaves as an element of the IV-th group of Periodic System. 322 Fast and Continuous Chemical Isolation of Short Lived Isotopes of Hf, Ta and W as Homologs of Transactinoid Elements 104, 105 and 106 Z. Szeglowski, H. Bruchertseifer1, V.B. Brudanin1, G.V. Buklanov1 0. Constantinescu1, Dinh Thi Lien1, V.P. Domanov1, L.I. Guseva1, M. Hussoinnois1, G.S. Tikhomirova1, I. Zvara1, Yu.Ts. Oganessian1 1 Joint Institute for Nuclear Research, 141980 Dubna, CIS. The short lived isotopes of Hf, Ta and W have been isolated and were synthesized at the U- 400 cyclotron of JINR Dubna, using a previously elaborated fast method of continuos chemical isolation of element 261104 [1] from nuclear reaction products. The short lived isotopes of iE9,i60Hfi i66-iG9Ta and 164,166,168W were obtained in the fouowing reactions:' 144 2Q Sm ( Ne,xn ) ,Hf 151,163Eu (20Ne>xn) 166,169Ta; 144Sm (24Mg,xn ) Nuclear ieaction products were transported directly from the irradiated targets to a separa- tion device by means of a NaCl aerosol jet. The aerosol participates were dissolved in a solution which was passed through three coupled ion exchange columns in which the separation of Hf, Ta and W from other elements was carried out. The method imitates well the conditions of the isolation of trantactinoid elements 104,105 and 106. References [1) Z. Szeglowski, H. Bruchertseifer et al., Radiochimica Acta,Sl, 1990, 71. Model Experiments for Separation of Elements 104 and 105 H. Bruchertseifer1, F. Haberbersger2, N. Trautmann2, M. Schadel3,W. Brucle3, G. Skarnemark4, 0. Alstad5, V.P. Domanov6, Z. Szeglowski, M. Vobecky6 1 Central Institute for Isotope and Radioactive Research, Leipzig, Germany. 2 Institute of Nuclear Chemistry, INC, Mainz, Germany. 3 GSI mbH,Darmstadt, Germany. 4 Chalmers UrJversity of Technology, Goeteborg, Sweden. 6 Department of Chemistry, University of Oslo, Norway. 6 Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, 141980, Dubna, CIS. The transactinides ( Z>103 ) were produced in very low quantities in nuclear reactions at cyclotrons and at the present time we know only short-lived isotopes. For the study of the chemical and physical properties of these elements and for search for new isotopes, one needs, first of all, fast methods for their separation from the actinides, the target or catcher materials and from the nuclear reaction products,produced simultaneously. Complexes of Zr, Hf, Nb. Ta and the element 104 (Ku) with fluoride ions allow one to separate the elements of the IV and 323 VB group of the Periodic System from lantanirles and Ku from nctinides which disturb their quantitative analytical determinalion. In diluted HF solutions the Innthanides and the actii>id«-..s exist only as positively charged ions and are sorbed on cation exchange resins, whereas tin; union complexes of Zr, Hf, Nb, Ta and element 104 pass the corresponding ion exchange separation columns. In a new on-line experimental approach we have combined the radioactive nuclide (fission products, produced in the Mainz TR.IGA reactor ) transport, using an aerosol stream ( N2 + KC1 ) with the dissolution of the particle matter and the radionuclides with the SISAK 3 degassing unit following by continuous separation processes. Such rad i o chemical technique can be used for studies of nuclides with half-lives down to 1 s. In the first investigations of the sorption of Zr and Nb on strongly acid cation exchange resins from diluted HNO3 /HF solution we found conditions for separation of Zr and Nb . Cation exchange resin adsorb lanthanides and 5 Zr fromHN03 (O.lM)/HF ( 10"" - 10~ M) solution. Niobium is not retained. It means that the sorption from, aqueous solutions of HNO3/HF c?_n be used not only for analytical separations, but also to study small differences in the complex formation and hydrolysis processes of the IV B and V B group elements. The methods for very fast and continuos separating of niobium, zirconium and lanthanides and investigating their chemical properties can also serve as a model for the study of chemical and separation processes of elements 104 and 105. ')p\ The Ion Exchange Behaviour of Element 104 in Hydrofluoric Acid Solutions Z. Szeglowski, H. Brucherlseifer1 ,et al. 1 Zentralinstitut fur Isotopen - und Strahlenforschung, Leipzig, Germany. A method of rapid continous isolation of kur chato vi um of a 248Cm target with 18O ions has been developed. The nuclear ieaction products were transported a distance of 10 meters from the target to an apparatus for chemical separation by means of a KC1 aerosol jet. The aerosol participates carrying adsorbed radionuclides were disolved in 0.2 M HF and the solution was passod through three ion exchange columns. In the first cationic column the transplutonium and some other elements generated directly in the bombardment were removed from the solution. In model experiments, the decontamination factors of the Zr(IIf) fraction from rare earths and transplutonium elements in various solutions were determined, values as high as 10B to 106 were achieved. In the next, anionie column kurchatovium was sorbed, while the last, cationic column re- tained the decay products of Ku. The identification of 261Ku ( T^ = 65 s ) was performed by observing its great-granddaughter Es ( Tj/2 = 20 d), after the latter (together with 2B3Fm) had been desorbed from the third column. In a 24-hour experiment some 2000 Ku atoms were produced, they were detected with the efficiency as high as 0.25 . It has been shown for tin- first time that in HF solutions Ku forms stable anionie complexes which are sorbed on an anion- exchange resin, i.e., the element behaves similar to Zr and Hf, the members of the IV-th group of the transition metals. The method opens up the possibility of obtaining quantitative data on the properties of Ku in solutions. Results of the experiments are presented in Fig.l and Fig.2. 324 1000 4. \ ł----ł—) Es 20 30 (0 days ENERGY ( McVl Fig.2. Decay curve Of the E =6.63 MeV in the TPE fractions a desorbed from the cation exchange Fig.l. Alpha spectrum of TPE desorbed columns: from the cation exchange columns: 1-first column (direct 254Es+Z53Es); __ 1 - first column; 2r - third column. 2-third column ( Fm -^ 253 Es ). The Recovery of Lanthanides from Phosphogypsum. ZoJL The Application of Radioisotopes and Gamma Spectrometry to Determination of the Group# Extraction Coefficient of Lanthanides B. Kubica, I. Kulawik, J. Kulawik, J.W. Mietelski and J. Mikulski Extraction of rare earth elements with 0.5 M nonylphenylphosphoric acid in n-decane from sulphuric acid was studied. In order to obtain the results of extraction for all group of lan- thanides, isotopes of 144Ce, 164+1S5Eu and 170Tm were used because they are first, central and final part representatives of the chemical group of lanthanides. The extraction coemcients of Ce, Eu and Tin as a function of sulphuric acid concentration in the aqueous phase were found. In the first stage of investigations the extraction of each individual isotope was done. To save time and keep conditions of measurements identical, simultaneous extraction of all the three isotopes was performed. The extraction coemcients of Ce, Eu and Tm were d jtermined by means of gamma spectrometrical analyses . To resolve the overlapping lines in the spectrogram (e.g. those of 156Eu and 170Tm) the measurements were performed on line with an IBM PC computer. An adequate program for numerical separation of individual lines has beeu elaborated earlier. Results of these analyses are presented graphically. The results indicate the possibility of summaric extraction of elements feasibility of determining the individual extraction coemcients from the results spectroscopic analysis. Even in unfavorable conditions like the use of isotopes whose lines partially overlap the result- obtained on the way of individual extraction agree well with those obtained from group extraction. 325 lo'b Extraction of Actinium with Di-(2-ethyhexyl)phoshoric Acid from Hydrochloric and Nitric Acid Solution Z. Szeglowski and B. Kubica Extraction of actinium and europium extraction by di-(2-ethylhexyl)phosphoric acid (HDEHP) in n-heptane was studied as a function of the hydrochloric and nitric acid concentrations. It was found that actinium and europium extraction coefficient decreased lineaxy with acid concentra- tion with the slope of-3 in the whole investigated concentation range. The stability constants of 2 +2 actinium and europium complexes Ac(X~)+ and Eu(X~) with Cl~ and N03~ ligands were determined. Our results show that the actinium formed complexes with Cl~ are less stable than those withe with N03" ligands. It was found that the extraction of actinium from HC1 solutions is much better than from the HNO3 solutions. Aerosol's Radioactivity Measurements in Ground Level Air in Institute of Nuclear Physics K. Kozak, M. Jasińska, P. Macharski and J.W. Mietelski Aerosol sampling station ASS-500 is located in the Institute of Nuclear Physics. At 2m above the ground level a Petrianov filter (area 0.26 m2 ) is installed in a horizontal hold':. Aerosol samples are collected using a high volume pump at the initial air flow rate of 400m/h. Particles of up to 35pm aerodynamic diameters would reach the filter. Depending on weather conditions, aerosols from more than 35000 m3 of the air are collected during each sampling period of one week. Warning system with G-M counters for measurement of current total gamma beta filter activity during sampling is installed above the filter. The filter is compressed to obtain o disc of 5 cm in diameter, 3-6 mm thick. The first short measurement of 15 minutes is performed as soon as possible to estimate the activities of short living isotopes and check if any man-made nuclides are present in the air. Next, 3 days after filter has been removed, the basic measurement is performed for 1000 minutes. All measurements are performed with low-background gamma spectrometer with the Ge(Li) detector. A weekly raport of result is issued with the data for Be, 40K, ł37Cs, 226Ra, 22BRa, and those of minimal and maximal value for last year's period (see Table). Any anomalies of any man-made radionuclides are also presented. The reports axe submitted to National Atomic Agency (PAA). Those routine air contamination measurements are intended to constitute, in future, part of the Polish Radioactive Monitoring System. TABLE Long lived isotopes concentration ranges in the ground-level air in 1990 and 1991. Activity in the air I YEAR YEAR ISOTOPE 1990 1991 ISOTOPE 1990 1991 Be-7 845 - 3430 440 - 4690 Ra-228 O - 14 0-18 Cs-137 O - y 0-12 Ra-226 O - 230 O - 29O K - 4O O - 160 O - 223 326 90 2 Results of Sr and W40pu? 238pu^ 24iAm Measurements in Some Samples of Mushrooms and Forest Soil Prom Poland J.W. Mietelski, J. LaRosa1, A. Ghods1 1 Chemistry Unit, IAEA Laboratories Seibersdorf, Austria Activities of plutonium, americium and e0Sr were determined for 4 samples of forests soils (humus and leaves layers), leaves of fern (2 samples) and some species of mushroom (4 samples). Data were compared with those obtained in the previous INP works [1],[2] concerning caesium activity. The IAEA recommended standard radiochemical procedures have been used for sample preparation. The determination of strontium has been done using the LSC - Cherenkov effect method. Plutonium and americium measurements were performed on a alpha-spectrometer with a silicon surface barier detector. Sources were prepared using the NdF3 co-precipitation method. All measurements have been done at the IAEA Seibersdorf Laboratories. The 90Sr activities range from 0.6 Bq/kg (in the mushroom sample) to 48.4 Bq/kg (in fern leaves;, 239+240pu activities range from 0 + 0.03 Bq/kg (mushrooms, fern) to 10.8+0.4 Bq/kg (humus). The maximum value for 241Am is equal to 2.4 Bq/kg (humus sample) and that for 238Pu it is 0-85 Bq/kq also in humus sample. The origin of contamination (Chernobyl or nuclear explosions) has been disscused and following conclusions drawn: 1. The observed plutonium activity originates mainly from atmospheric fallout of past nu- clear weapons testing. However, in the leaf layer of soils there appears to be contribution from the Chernobyl accident. 2. The humus layer of soil can accumulate plutonium very strongly; the observed activities (4 and 11 Bq/kg) are higher than expected from global fallout (typically 0.05 to 2 Bq/kg). 3. The mushroom species which were examined appear to be unable to accumulate Sr and Pu radionuclides. 4. More detailed, more careful and larger scale investigations of alpha-emitting actinides and radiostronthun in the forest ecosystems of Poland would undoubtedly be very interesting aud would lead to a better understanding of the radioecology of artificial radionuclides in such complex systems. References [1] M.Jasińska, K.Kozak, J.W.Mietelski, J.Barszcz, J.Greszta. /. Radioanal. Nucl. Chem., Let- ters, 146 (1990) 1-13. [2] M.Jasińska, K.Kozak, J.W.Mietelski Proceedings of the International Symposium on Post- Chernobyl Environmental Radioactivity Studies in East European Countries, Kazimierz, Poland, 17-19 Sept. 1990 71-77. The Map of Radioactive Contamination in the Forests of Poland J.W. Mietelski, M. Jasińska, K. Kozak, B. Kubica and P. Macharski Our laboratory is working within the Polish Government program of survey of the radioactive contamination of the forests. By the end of 1991 every one of 404 forest inspectorates was obliged to collect and send us, five kinds of samples: 327 1. 50-100 g. of dried mushrooms Xerocomus badius. 2. 50-100 g. of dried mushrooms of other species. 3. a leaves layer (Aoi) of forest soil from a 30cm x 30cin area. 4. a humus layer (Aj) of forest soil from a 20cm z 20cm area. 5. 50-100g of dried leaves of plant Vacilium mertylus. All measurements are performed usii.g the low-background gamma spectrometer with a Ge(Li) detector. In consequence we are going to prepare maps (one for each kind of sample) of current contaminations of forest ecosystems with caesium. The first step is to measure samples of Xerocomus badius only. This species is known [1),{2] for its strong caesium accumulation, so that geographical distribiution of caesium contamination results can be obtained most easily due to short measurement times. We will measure other kinds of samples next. By the end of 1991 more than 200 samples were analysed. Caesium isotopes (137Cs and 134Cs) contamination level range from 120 to 181000 Bq/kg (d.in.). The highest value (164000Bq/kg 137Cs and 17000Bq/kg l34Cs) was obse.rved in sample collected ca. 10 km NE from Opole. The first map of contaminations based on the measurements of just Xerocomvs badius should be prepared in early spring of 1992. Frequency distribution of 13rCs activity level in Xerocomus badius samples is presented below. I « 1 * 7 tO 13 10 19 22 25 30 40 50 80 130200 • Ctivity I Jingo [kBq/k|J Invl Figure I: Frequency distribution of 137Cs activity level in Xerocomus badius samples References [1] D.C.Aumann, G.Clooth, B.Steflfan, W.Steglich Angew.Chem, 101(1989) 495-496. [2] M.Jasińska, K.Kozak, J.W.Mietelski Pivceedings of the International Symposium on Post- Chernobyl Environmental Radioactivity studies in East European Countries, Kazimierz, Poland, 17-19 Sept. 1990 71-77. Concentration of Natural Radioactivity Elements in Wastes of T.Sendzimir Steel Works and in Building Materials M. Jasińska, K. Kozak, P. Macharski, J.W. Mietelski and J. Schwabenthan Industrial activity of the T.Sendzimir Steel Works generates large quantities of solid wastes deposited in the environment. Solid wastes consist of microne and submicrone fly ashes emitted 328 to the atmosphere and large size particles deposited on a heap. The biggest waste produces arc Blast Furnance and Power Station. All wastes contain natural radioactive elements from uranium (234Pa, "eRa, 214Bi ) and thorium scries (228Ac, 212Pb, 2O8T1) and 40K. In this work concentration of those radionuclides in 35 samples of wastes such as: moulder's sand, slag, ash, waste water and others have been measured using low-background computerized gamma- spectrometer. Samples were collected in July and September 1991. Concentration of 22flRa and 2I4Bi radionuclides is low, in most samples not exceding 20 Bq kg"1. Only for blast furaance slag it is 100 Bcj kg"1. Power station ash and slag contain a typical burned coal waste concentration (ca. 603q kg"1) ->f 226Ra. In almost all samples concentration of radionuclides from the thorium series are less then 30 Bq kg"1 oceing jn most cases less than 10 Bq kg"1. The only exception are samples from the Power Station, where they reach 50 Bq kg"1. Radionuclide concentration in waste water samples collected from the waste ashes heap was 2.5 mBq ccm"1 which is much more than the value allowed for drinking water in Poland (equal 0.11 mBq ccm"1 ). These results show that standard deposits of ashes and slugs do not influence the level of environmental radioactivity outside the area. The method of measurements used for this work is also used for determination of natural radioactivity in building materials. During 1991 more than 50 samples of building materials and raw materials as clay, burned coal ashes and slags were analysed. All those samples had smaller activities than maximum values allowed by the Polish law. PUBLICATIONS: I. Articles: 1. J. Grzybek, M. Jasińska, K. Kozak, J.W. Mietelski - Incidence of radioactive 134Cs and 137Cs caesiiun isotopes in friu't bodies of selected Polish mushrooms /in press in Journal of Canadian Botanies/ 2. M. Paluch, Z.Szeglowski - The effect of n-aliphatic alcohols on electrophoresis of carbon black suspensions in paraffin oil, Tenside Surf.Det 28 (1991) 159. 3. Z. Szeglowski, H. Bruchertseifer, et al. - The ion exchange behaviour of element 104 in hydrofluoric acid solutions, Radiochimija 33 (1991) 70-77. 4. J. Greszta, J. Barszcz, M. Jasińska, J.W. Mietelski - Contaminations of Southern Poland Forests with Sulphur and Some Radioisotopes ; Zeszyty Naukowe Akademii Rolniczej, Leśnictwo 20 no. 254 (1991) 393-415. :n Polish 5. Z. Szeglowski, J.S. Korotkin - The electro spraying method for preparation of both thin and thick targets from organic solution, Pribory and Technika Eksperimenta, 1 (1991) 206. 6. Z. Szeglowski, B. Kubica - Extraction of actinium with Di(2-etylhexyl)phosphoric acid from hydrochloric and nitric acid solutions, J.Radioanal. Nucl. Letters 153 (1991) 67-74. 7. Yu.Ts.Oganessian, S.A.Karamian, Y.P.Gangrski, B.Górski, N.B. Makarov, Z.Szeglowski, Ch.Briancon, J.F.Ledu, R.Menier; M.Hussonnois, 0.Constant inescu, M.I.Subbotin, - Pro- 178m2 duction chemical and isotopic separation of the long-lived isomer Hf(Ti/2 = 31 years), JINR Rapid Communications 3 (1991) 49. 329 II. Contributions to Conferences: 1. J.V. Aleksandrov, A.A. Astapov, S.K. Vasiliev, R.B, Ivanov, A. Kolacnkowski, R. Miruak, M.A. Mikhailova, A.F. Novgorodov, T.I. Popova, V.P. Prikhodtseva - Cross sections for (p,X) reactions on Ti, V, Ga and Ge at E =660 MeV; Tezisy dokladov Ąl-go soveshchaniya po yadernoi spektr. i str. at. yadra. "Nauka", Leningrad (1991) 472. in Russian 2. J.V. Aleksandrov, A.A. Astapov, S.K. Vasiljev, R.B. Ivanov, A. Kolaczkowski, R. Misiak, M.A. Mikhailova, A.F. Novgorodov, T.I. Popova, V.P. Prochodceva - Cros3 sections for (p,X) reactions on Zr at E =660 Mev; Tezisy dokladov Ąl-go sovieshchaniya po yad. spektr. i str. at. yadra "Nauka', Leningrad (1991) 488. in Russian 3. B. Kubica, I. Kulawik, J. Kulawik, J.W. Mietelski, J. MikuMi - The Application of Ra- dioisotopes and Gamma Spectrometry to Determination of the Group Extraction Coef- ficient of Lanthanides; Proceedings of the 5th Meeting on Nuclear Analytical Methods, Dresden 1991, May 13-17 (in press) 4. M.Jasińska, K.Kozak, J.W.Mietelski, P.Macharski - Effective Dose Equivalent for Adults and Children in Poland as the Result of Mushroom Consumption; Proceedings of the 5th Meeting on Nuclear Analytical Methods, Dresden 1991, May 13-17 (in press) 5. Z. Szeglowski, H. Bruchertseifer,ef al. - Rapid method of continuos isolation of some short-lived transactinide nuclides from nuclear reaction products, Abstracts International Congress on Analytical Sciences, Chila, Japan, 25-31, August 1991, 773. HI. Reports: 1. A.Bichonski, E.M.Dutkiewicz, W.Knap, P.Macharski, J.Mikulski, P.Zagrodzki - Investiga- tion on some metals levels in wheat samples; INP Report No 1567/C (1991). 2. H. Bruchertseifer, F. Habergerger, T. Trautmann, P. Zimmerman, M. Shadel, W. Brude, G. Skarnemark, 0. Alstad, V.P. Domanov, Z. Szeglowski, M. Vobecky - Model experiments for separation of elements 104 and 105, GSI Scientific Report, Darmstadt 91-1 (1991) 265. 3. Z.Mazgaj, J.Mikulski - Determination of the temperature dependence of yield of At-211 isolation from alpha-irradiated Bi2O3 target; INP Report No 1568/C (1991) in Polish 90 4. J.W. Mietelski, J. LaRosa, A. Ghods - Results of Sr, and "9+240pu> 238pUj 24iAmj measuiements in some samples of mushrooms and forest soil from Poland; INP Report No 1575/B INTERNAL SEMINARS: 1. P.Grychowski - "Production and isolation of J-123 from the tellurium target", 5.03.1991 2. J.W.Mietelski - "Measurement of Sr-90 and alpha-emitters in the environmental samples", 6.05.1991 3. M. Borkowski (ICNT, Warsaw) - "Extraction of lanthanides and actinides", 10.09.1991 4. M. Szalkowski - "A concept of desulphurization of flue gases with use of pyrite" ,10.10.1991 330 5. P. Macliwski - "Report on - the Advanced Regional Training Course on Determina- tion of Rndionndides in Food and Environmental Samples - Karlsruhe, June 3-28 1991", 24.10.1091 0. Z. Mazgaj - "Determination of tlie temperature dependence of yield of At-211 isolation from alpha-irradiated BijO3 target", 10.12.1991 EXTERNAL SEMINARS: I. J.W. Mictelski - Results of strontium-90 and alfa-einitters measurements obtained ditring stay at Seibersdorf: Chemistry Unit Seminar, 26.04.1991 IAEA Laboratories Seibersdorf, Austria 331 •i '\ Department U of i ' Reactor \ * Technology :\ /• V', i- ,; ;, DEPARTMENT OF REACTOR TECHNOLOGY FOREWORD Works of the Department of Reactor Technology concern two kind of activi- ties: evaluations of advanced reactor technologies (especially High Temperature GaB- Cooled Reactors - HTGR) from point of view of the needs of Polish energy system and laboratory research in the field of high temperature metallic materials. Recently pre-feasibility study of Modular HTGR applications for co-generation in Poland has been carried out. Polish energy system ia very specific and has to be reconstructed. In primary consumption balance coal contributes 80% and large fraction of this coal is used as a final energy carrier. That creates enormous ecological problems. What Poland most urgently needs are clean heat sources for district heating and additional electricity generating capacity. In Polish towns over 50% of dwellings are connected to district heating grids. Due to unique safety features MHTGR as co-generation plant seems to be the most attractive option for Poland in corning decades. Laboratory research efforts have been concentrated on high temperature alloys for heat exchanging components. The essential results obtained recently in this field concern structural changes caused by creep and creep-low cycle fatigue interactions and changes due to "hydrogen shocks". It has been established that identical thermal cycling of Incoloy 800 specimens in helium and hydrogen environment generates very different structural changes in both cases. In the last year sharp cuts in founding for research related to n-iclear power took place in Poland. It limits laboratory investigations especially in areas where cooperation with other laboratories are necessary. This situation causes that some members of the Department get involve in research and activities not directly related to the main efforts of the Department. Edward Obryk Head of Department of Reactor Technology STAFF: 1. Grażyna Bieńczyk-Żardecka * 6. Eugeniusz Lisiecki * 2. Zygmunt Chyliński 7. Barbara Kumor-Obryk 3. Marek Cwikilewicz 8. Stanisław Maranda 4. Andrzej Górski 9. Halina Michalik * -secretary 5. Andrzej Jakubowski 10. Edward Obryk - head of the Department * part-time 333 9/>8 FACILITIES FOR TUBES TESTING UNDER SIMULATED HTGR SERVICE CONDITIONS M.Cwikilewicz, A.Jakubowski, M.Lemler, G.Zapalski The test programme for the creep and low cycle fatigue testing of tube materials under simulated High Temperature Gas-Cooled Reactor (HTGR) hase been initiated in the Department several years ago. An experimental rig has been constructed to allow testing with methane reforming gas, or the other gaa atmospheres, on the inside of tubes and impure HTGR helium, on the outside simulating the service conditions of the heat exchanger in the High Temperature Gas-Cooled Reactor process heat plant. The laboratory provides the metallic samples for complex microstructural investigation to assess the effects of service conditions on structure of high temperature alloys. The system consists of five single specimen creep machines, closed helium loop v/ith purification system, the impurity- injection unit and the additional open gas loop. The helium impurity mix- ture passes throught the gas-tight re- tort surroun ded by a tube furnace on the outside of the tubular specimen. An additional gas mixture flows inside of the specimen. Any sealed connections at the additional gas loop are outside of retort to protect possible gas trans- port between loops. Thus the mechan- ical deformations and structure change of the tube can be examined under the influence of well defined different cor- rosive attack inside and outside of the test specimen tube. Photo 1. Partial view of the testing laboratory. In the foreground are five single specimen creep machines. The main parts of the single specimen creep machine are a gas-tight retort sur- rounded by a tube furnace and a lever system for applying the load to the specimen throughout two stressing tubes welded directly to the ends of the specimen. The furnace has eight heating zones connected in series. The specimen temperature is measured by Ni — CrNi thermocouple inside of the specimen tube. The maximum temperature deviation from an average temp, along 100mm specimen gauge lenght IH \"C. Welded specimen joints are 200mm apart and they are outside of hot heater /.one Multiaxial stress can also be applied by the difference of pressures between the mtrernal and t,he external gas atmospheres. Three, (if the single specimen creep machines have been modified for low cycle 334 fatigue tests. The pneumatically operated piston unit has been added to enable increase of the dead load acting on the specimen. The unit is fully controled by an electronic system. Time intervals of loading can be set up in a wide range. The nominal impurity levels in simulated primary HTGR helium circuit lie in the range of (0.1 — l)Pa. In order to reduce depletion effects due to reaction between the impurities and the hot metallic surfaces in the creep furnaces, gas flow rates of 1 to 2 normal litres per hour throught each furnace are used. Flow is forced by means the electronically controled membrane electromagnet pump. After passing through the furnaces, the gas is ted through purification system which comprises the a CuO bed to oxidize hydrogen and carbon monoxide, molecular 5A sieve to absorb water and carbon dioxide and liquid nitrogen cooled activated charcoal trap to remove methane, nitrogen and water. The impurities remaining in the gas after purih'cation are below the detection limit of the gas chromatograph (< 0, OlPa). At intervals the purification system requires regeneration, during which the twin purification traps are brought into operation. The pure helium (99,9999) is doped by mixing helium containing higher propartions "of the impurities (H2, CH\> CO - in % range) with purified helium at the specific ratio. The injection of the mixture to the helium loop is accomplished by micrometering valve and electrically controled pressure stabilisation system. The mixture passes throught liquid nitrogen trap to remove water wapour before injection. The water in the helium loop is dopped separately just before furnaces. The hydrogen stream is controled by electrically operated system and is converted into water at a CuO bed to acsure precision water dopping. Simulated steam reforming gas, intermediate heat exchanger helium and other gases can be applied as an additional gas atmosphere inside of tlie tubular specimen. Aparat from steam reforming gas all simulated atmospheres are prepared as a mixture in a high presure vessel and than is led throught specimen connected by means mi- crotubes. Afterward the mixture is released to atmosphere. The steam reforming gas can be produced in the microreformer based on the catalytic methane water chemical reaction with nickel catalizator at high temperature. Flow and presure of additional gas is electronically controlled. The composition of the gas is measured at the entrance and the exit of furnaces, as well as -\t the exit of the purification bop by Carlo Brba gas chromatograph with helium detector. References: 1. M.Ćwikilewicz, M.Lemler, G.Zapalski, INP Internal Report NZX/60/82, Cracow 1982 2. M.Ćwikilewicz, A.Jakubowski, G.Zapalski, INP Internal Report NZX/61/82, Cracow 1982 3. Profiles of Facilities Used for HTR Research and Testing, ING HTR/5, IAEA, Vienna 1980. 4. A.Jakubowski, W.Kulinowski, G.Zapalski, BMP Internal Report NZX/114/88, Cracow 1988 5. G.Zapalski, INP Internal Report NZX/115/88, Cracow 1988 335 MEASURING STAND FOR HYDROGEN TRANSPORT AND THERMAL AND HYDROGEN SHOCKS INVESTIGATIONS M.Cwikilewicz, A.Jakuhowski, G.Zapalski r*"*^*™^ ' Fig.l Assembly drawing of the main part of measuring stand for hydrogen transport and thermal and hydrogen shocks investigations. The tubular specimenis fastened in the main axis of the chamber. The main part of apparatus for hydrogen transport and hydrogen and thermal shocks investigations is a stainless steel cylindrical chamber with volume ca. 2 liters. The tubular specimen lenght ca. 100mm is fastened vertically in the main axis of the chamber. Large range of tubes diameter (providing they have sufficiently small cross section area) can be used. The sealing of bottom and top cover of the chamber is accomplished by a silicon rubber o-ring. The specimen is sealed using electron 336 beam welded flanges and metal and silicon rubber gas-tight elements. Direct gaa pass beetwen atmosphere inside and outside of the specimen, is impossible due to design of the chamber. The stressing of the specimen is by using direct loading or through a lever system which allow to apply a tension force up to 2000JV. The specimen is ohmically he ated. The alternating current powered heating system allows the specimen to be headed very fast. For exemple, the specimen heated from room temperature can reach stable 900°C in time lees than 1 minute. It is because of the two stages heating. High power first stage heats the specimen up to the temperature 8eted up before. Than, electronically operated control unit swith over heating to low power next stage. The next stage of heating allows the specimen temperature to be maintained at stable level during time interval seted up before. Volume inside of the specimen is connected to closed gass loop. In order to reach high rate of cooling of the specimen (from 900° C to 200° C in time of less than lmm.) high flow of gas inside of it ia forcet by means electrically controled membrane electromagnet pump (max. flow 10//rmn at 2, AM Pa). Gas flow control and gas preassure control provide almost identical specimen coding conditions for two different coolants, especially helium and hydrogen. Volume outside of the specimen is connected to chromatography carrier gas line. In order to measure rapid hanges of hydrogen permeation during thermal cycle (heating and cooling of the specimen) in time of a few minutes a volume of carrier gas at the vicinity of the specimen have been reduced to approximatly 30m/. It was accomplished by cylindrical oxide Her covered metalic housing surranding the specimen. For low carrier gas volume at hydrogen output side, concentration of hydrogen ia high enough to use direct dopping thermal conductivity detector. With argon as a carrier gas an accuracy of 2-10~GNcm3H% f cm2a can be achived. Measuring stand is equiped with electronic control system which allow cyclic experiment (heating, cooling) to be run automatically. The measuring stand after some rearangement can be used for hydrogen perme- ation and possibly hydrogen diffusion coefficient measurements. In this c..se hydrogen input side is in outside volume of the specimen. Inside of the specimen flows chro- matograph carrier gas. References: 1. M.Lemler, G.Zapalski, J[NP Internal Report NZX/96/86, Cracow 1986 2. E.Obryk, G.Zapalski, INP Internal Report NZX/98/86, Cracow 1986 3. A.Jakubowski, E.Obryk, G.Zapalski, INP Internal Report NZX/113/88, Cracow 1988 4. M.Ćwikilewicz, A.Jakubowski, INP Internal Report NZX/122/89, Cracow 1989 337 HYDROGEN AND THERMAL SHOCKS IN METALLIC MATERIALS UNDER MECHANICAL STRESSES M.Cwikilcwicz, A.Jakubowski, E.Obryk, K.Spiradek (OEFZ, Setbersdorf) In many high temperature nuclear heat application proceses (i.e. steam methane reforming) high partial preasure of hydrogen in heat exchanger is expected (1). The temperature changes during service operation (start up, shut down, power changes) of nuclear heat application installation, are the main source of low cycle fatigue of high temperature components. The limit on rate of temperature change of those components is based only on the thermal stresses (2). Possible hydrogen supersatura- tion of the suddenly cooled metal is generally overlooked. Although, it is well known that high hydrogen concentration in steel may be a source of additional stresses , nucleation and structural changes generation, finally material damage. The hydrogen diffusion coefficient in steel is low in comparison to heat diffusion coefficient. So ther- mal changes rate is to fast to allow hydrogen transport from inside of cooled metals. Taking into account, that hydrogen solubility in metals changes approximately by or- der of magnitude with temperature changes of 500°C, it is obvioua, that fast cooling, hydrogen saturated metals can lead to hydrogen supersaturation (3). The aim of this experimental work is to call attention to hydrogen shock problems and to provide experimental evidence of hydrogen shock existance. For investigation H. Wiggins Incoloy 800 have been chosen, the alloy which is known as a hydrogen resistant material. The tubes length of 100mm, diameter of 28mm, wall thickness of 1,5mm were investigated. The experiments were done using the measuring stand for hydrogen and thermal shock investigation (4). Two twin experiments have been carried out. However, one difference was es- Bential. For the first specimen pure helium as a coolant have been used, for the second specimen hydrogen (p=0.8 MPa). During both experiments the specimens were cyclicaly heated and cooled with temperature in between 200°C and 760°C. The specimens were heated itself by means alternating electric current. The cooling by adequately helium and hydrogen flow were accomplished. Heating time was 50*. High temperature was mentaine durring 90s. provideing hydrogen permeation stedy state, then hydrogen saturation of the specimen. It was checked up by means of gas chromatograph. The specimen cooling time was 505. The specimen axial stress of 70MPa have been applied. Experiment have been run up to specimen rupture. After experiments a microstructural examination comprising transmission elec- tron microscopy (TEM), scanning electron microscopy (SEM) and the X ray structural analysis have been done. 338 Fig. 1 The specimen material, a thermal stress only subjected (helium coolant) does not show any structural changes. The structure shows, to be close to equi- librium with developed recovery proces- ses Fig.2 The specimen material, a thermal and hydrogen stresses subjected (hydrogen coolant) shows great structural changes, indicating high mechanicall stresses and strains existance. Even local micro-cracks can be observed Distinguished structural diferences between the two specimen materials proofs the exiatance of a hydrogen shock efect. This confirms our earlier experimental results (5). The question of nature of hvdrogen shocks phenomenon remains still open. So continuation of the investigation may be quite interesting. References: 1. Nuclear Heat Application, Proceedings of a TCM and Workshop, Cracow, 5-9 December 1983, IAEA, Vienna, 1984 2. H.Nickel, T.Koudo, P.L. Rittenhouse, Nuclear Technology 66 (1984) 12 3. J.A.Golczewski, B.Kumor, K.Spiradek, Postępy Techniki Jądrowej, 23 (1979) 999 4. MCwikilewicz, A.Jakubowski, G.Zapalski, Measuring stand, this Report f). A.Jakubowski, E.Obryk, K.Spiradek, Hydrogen shocks and hydrogen transport problem, INP Internal Raport NZX/113/88, Cracow 1988 339 HIGH TEMPERATURE CREEP WITH AN ADDITIONAL!, FATIGUE LOADING OF ALLOY OF ALLOY 800 TYPE M.Cwikilewicz, A.Jakubowski, K.Spiradek (OEFZ Seibersdorf) Creep-low cycle fatigue interaction ia an important problem for material science but practical results are of primary importance for applications. Both of those phe- nomena exist simultanously during service operation in high temperature components of chemical technology installations, power plant installations, nuclear heat applica- tions. However, structural mechanisms causing damage are completely different in a case of creep and low cycle fatigue. Live time predictions methods for high tempera- ture constructions materials based on linear superposition effects of creep and fatigue often does not give satisfactory results. The aim of this work is to contribute to understanding of interaction beetwen phe- nomena related to high temperature creep and low cycle fatigue of metallic materials. Experimental runs lasting 1000 hours were carried out using facilities for tubes testing under simulated High Temperature Gas-Cooled Reactor (HTGR) service conditions (1). The experiment comprised high temperature creep with an additional fatigue loading. Five specimens (seamless tubes diameter 10mm, wall thickness lmm) were made of Polish made Alloy 800. An initial material have been examined at the In- stitute of Metallurgy, Academy of Mining and Metallurgy, Cracow, and according to (2) was to be adequate to standard in composition and structure sense. Experimental conditions were as follows: for five specimens tension uniaxial stress of 33MPa; temperature 800° C ± A°C\ environment: helium with impurities: #2 — 200ppm, CHi — 20ppm, CO — 20ppm (simulated primary coolant circuit of process heat HTGR). For one specimen an additional circumferential stress of 16MPa were applied by means \MPa gas pleasure difference inside and outside of tubular specimen. For three specimens an additional fatigue loading of 40MPa in different time interval of the experimental run, were applied. It were achieved by application of an additional fatigue loading during the first 100 hours for the first specimen, during the last 100 hours for the second specimen, during the whole experimental run for the third specimen. The three specimens were subjected approximately the same number of fatigue cycles with a holding time of 3mm. The specimens were subjected to one hour solution heat treatment at 1000° C in argon atmosphere. The creep curves for five specimens have been obtained. The curves show substan- tial divergences, which may indicate structural differences of the specimens material (Fig.l). After experiment a comprehensive microstructural examination including transmis- sion electron microscopy (TEM), scanning electron microscopy (8EM) and the X- ray structural analysis of the specimen material have been done. The results shows structural deviation of the material from the standard in contrast to - 340 itation of mechanical tests results repeatability. Also, presence of titanium carbide at large primary precipitations leading to loos of high temperature resistance, were found. Some structural features, typical to fatigue, in specimen subjected fatigue loading at the final stage of the experimental run, were found. It may suggest cor- relation between creep stage of the specimen and fatigue loading and structure of the specimen material. To get more conclusive results a further investigation are necessary with specimen of more reliable material. — I 2 3 • 4 6 10 20 30 tlmo (days) Fig.l Fig.2 l.the specimen with additional circumpheren- The specimen material subjected tial stress to fatigue loading at the final 2.the reference specimen stage of the experiment. Some 3.fatigue loading during the first 100 hours typical for fatigue structural 4.fatigue loading during the whole experiment features are shown. 5.fatigue loading during the last 100 hours References: 1. M.Ćwikilewicz, AJakubowski, M.Lemler, G.Zapalski, Facilities for tubes testing under simulated HTGR service conditions, in this Report 2. S.Gorczyca, F.Ciura, Metallurgical characteristics of domestic smeltings of Alloy 800H and Inconel 617, raport 2.351.37 of the Institute of Metallurgy, Academy of Mining and Metallurgy, Cracow, 1986. 3. K.Spiradek, H.P.Degisher, H.Lahodny, Proceedings of the SM on High Temper- ature Metallic Materials for Gas-cooled Reactors, Cracow, 1988 (IAEA, Vienna, 1989)p.54 4. K.Spiradek in Structure and Properties of Materials for High Temperature Re- actors, Metalurgia 39, ed. S.Gorczyca (Ossolineum, Wroclaw, 1990) p.49 5. K.Spiradek, A.Czyrska-Filemonowicz, P.Ennis, ibid, p.39 6. E.Obryk, ibid. p.7 341 Influence of the Structure of Metal Saturated by Hydrogen on some Characteristics of the Hydrogen Transport. Z.Chyliiiski and E.Obryk. The "structure-curve" representing the permaetian current of hydrogen in metalic samples - see Fig.l -goes beyond the predictions of all standard stochastic models of the transport phenomen. The heat transport by thermal conductivity provides us with a typical, "structure-less" heat current. This effect associated with hydrogen concentration exceeding some critical value c* was first observed by Beck, Bockris, McBreen and Nanis (BBMN) [3] and Fig.l is just taken from their publication. The explanation of the BBMN effect encounters severe difficulties for two ge- neeral reasons. First, because strongly nonlinear transport equations are required and second, because the very effect exhibits irreversible processes occuring to metal structure during diffusion proces which call for some (at least one) relaxation time Tref. However, in spite of these difficulties it is shown that e.g. such fundamental transport-characteristics as Uag can be evaluated within a large class of interesting models and - what is essential - t\ag is sensitive to the current structure, as can be read-off from Fig.2. This fact enables one to pick-out the sub-class of models capable to explain the BBMN effect. According to these models, tiag takes the form: 3 where A and B are some positive functions and i,°j = |J /A> denotes Uag for lin- ear diffusion equation with diffusion constantj?o and the thickness 1 of the (one- dimensional) sample. We see then that tuc from (i) can take even negative values which corresponds with the BBMN effect in question. Note also that the change of the medium (metal) structure for hydrogen concen- tration C(x, t) exceeding Ck creates a (moving) plane x(t) = f(t) which separates two different phases of the metal; C > Ck and C < Ck. Thus, function f(t) is implicitly determined from the equality: C{xk) = Ck (it) 342 1 2 3 4 5 6 7 8 9 10 x Fig.l The "structure curve" of the Fig.2 One parameter "p" trial functions for permaetian current of hyJrojcen ta- the permaetian current (normalized to zero ken from paper [3]. for x = 0) f(x;p) = (1 - e~*)4 + px*e~1-** plotted for five values of p. References: 1. F.Kazincjy, in "Hydrogen damage", ed. Cedic D.Beachem, American Soc. for Meta/s, Ohio, 1977, p.110. 2. R.A.Oriani, Hydrogen Embrittlement of Steel, Ann.Rev.Mater.Sci. 8 (1978) 327. 3. W.Beck, J.OM.Bockrie, JMcBreen, L.Nanis, Proc.Roy.Soc. A290 (1965)220. 4. A.R.7roiano, Trans.ASM, 52 (1960) 54. ó. R.E.PeierlB, "Some Simple Remarks on the Basis of Transport Theory", in "Transport Phenomena", Springer, Berlin, 1964. 6. W.S.Goraky, Z.Phys.Sovjei 8 (1935) 457. 7. L.S.Darken, Trano.AIME 180 (1949) 430. 8. L.S.Dorken, R.P.Smith, Corrosion 5 (1949) 1. 9. C.Alefeld et ol. "Hydrogen in Metals", Springer, Beriin, 1973. 10. AMc Naab, P.K.Foeter, TranB.Met.Soc. AJME 227 (1963) 618. U. R.A.0riani, Acta Metali. 18 (1970) 147. 12. A.J.Kumnick, H.H.Jonson, Met&U.TranB. 5 (1974) 1199. 13. J.CranJc, "The Mathematics of Diffusion", Clarendon Press, Oxford, 1956, p.279. 343 High Temperature Gas-Cooled Reactors Needs and Possibilities of Their Application in Poland Edward O bryk CONTENTS: 1. Introduction 2. HTGR, present status and development perspectives 3. Country's energy situation and potential part of HTGR in the energy syatem of Poland in near and more distant future 4. Possibilities to bring HTGR into energy market in Poland with different options of international cooperation 5. Evaluation of the potentiality of the Polish industry for participation in construc- tion of HTGR 6. Economic evaluations 7. Exemplary siting for the first HTGR power plant arid general outline of informa- tion campaign 8. Summary 9. Appendix I - International agreements on cooperation in HTGR technology 10. Appendix II - Acronyms used in publications about HTGR programs 11. References The study commissioned by National Atomic Energy Agency (101 pages, in Polish). 344 Dechanneling Cross-Section of cr-Particles by Interstitial Atoms in Palladium the paper by Z.Chyliński, A.Dunlop, J.Mory, both from Laboratoire d'Etude des Solides Irradi&s CBA/Ecole Poly technique, 91128 Palaiseau Cedex, France, A.P.Pathak from University of Hyderbad, Hyderbad 500134, India. The paper concerns the dechanelling cross-section of a-particles by interstitial carbon atoms in palladium. The measured cross-section amounts to: ~ (5.7 ± 2.6) x 10-3^2 The scattering by bare nucleus (carbon) widely overestimates the measured crot- section.Therefore a more realistic model is proposed which accounts for the screening effects by electrons around the nucleus and those of the palladium lattice. These modifications enable us to estimate the degree of ionization of interstitial carbon in palladium. References: /. J.J.Quillico, J.C.Jousset, Phys.Rev. B. U (1975) 1791. I. A.Dunlop, N.Lorenzelli, J.C.Jousset, Phys.Stat.Sol. A 49 (1978) 6Ą3. 3. J.Mory, CEA Report R- 4745(1976). Ą. I.M.Torrem, in "Interatomic Potentials", Acad.Press, 1972. p.%%. 5. J.M.Ziman, "Principles of the Theory of Solids", Camb. Univ. Press 1971 6. O.Krogh Andersen, A.R.Mackintosh, in "Solid State Communications", 0 (1968) 285. 7. F.Gautier, in "Propriitis electroniques des me'taux et alliages", Ecole d'EU de Royan, Masson, 1973. 8. S.Foner, R.Doclo, E.J.McNiff, Journal of Applied Physics, 39 (1978) 551. 9. B.Svensson, Ann.Phys. 18 (1933) 294. 10. H.F. Biggs, Phil. Mag. 32 (1916) 131. 11. C.Lerncr, in Thesis. Louis Pasteur Univ. Strassbourg (France) (197Ą). 12. Y.Quere, Journal of Nuclear Materials 53 (1974) 262. 13. G.N.Watson, "Theory of Bessel Functions", Camb. Univ. Press, 196t 14. J.lindhard, Mat.Fys.Medd.dan.Vid.Selsk. 34 (1965) 1. 15. F.ILEisen, G.J.Clark, J.Botiinger, J.M.Poate, Rad. Effects 13 (197%) 93. 16. R.H.Siller, R.B.McLellan, M.L.Rudee, J. Us Common Met. 18 (1969) 43%. 17. H.J.Wernicke, Ph.D.Thests (1973), Univ.Kiel. (Germany). IS. H.L.M.Bakker, M.J.C.de Jong, P.M.Opp&neer, R.Grkssen, A.Lodder, K.Vis, H.Brodowsky, J.Phys. F 10 (1986) 707. 345 Quantum and Relativistic Physics - Relationism and Relativism Z.Chyliński (hook in Poliah) The book concerns the fundamental conflict between nonlocality of quantum theory of "relations" and locality of the Minkowskian spacetime LĄ of "events". In the first - critical - part the present theory based on the I^-eventism is analyzed and its vague points connected particularly with the theory of measurement are discussed. This is confronted with the Galilean G^-eventism free of this conflict according to the singu- larity of the G«-symmetry G which implies that events of GĄ coexist with relations of the Rj-geometry of internal space time. Exactly this singularity is responsible for tremendous successes of non-relativistic quantum mechanics. In the second part of the book the hypothesis of internal spacetime RĄ of re- lations is extended to physics of finite universal constant h/c. The Z/4-geometry of measurement then gets the status of the limiting case of the /^-geometry conditioned by "situations" accompanying (in particular) any measuring process performed by heavy, classical measuring devices. In consequence, the relativism of external space- time (L4 and/or G4) becomes a conditio sine qua non of any measurement which must separate the entity measured from physical characteristics of measuring tools. Three kinds of the ^-effects - alien to any theory based on the Z/4-eventism - are analyzed which are capable to prove-disprove the hypothesis of relationism. The book contains about tOO pages and 110 rejerences to the literature. 346 Quantization of the Nambu-Jona-Lasinio soliton and the nucleon-delta split- ?4 (=, ting K.Goeke\ A.Z.Górski, F.Gninuner1, Th.Mcissncr*, H.Reinhnrdt2'3, R.Wunsch' 1 Theoretische Phttstk II, Ruhr-Universiiât Bochum 7Zmiraliniiiiui für Kernforschung Roiendorf, Dreiden 3Insiiiui für Theoretiiche Physik, Univtrs\läi Tübingen, Tübingen In recent, years the Nambu-Jona-Lasinio (NJL) model [1] has become popular as an effective theory describing low energy QCD phenomena. The reason is threefold: the model is the simplest quark model which provides spontaneous breaking of chiral symmetry, second, it yields quite reasonable, results for the mesonic and baryonic sector and third, there are various indications that it indeed serves as a long wavelength limit of QCD [2]. However, in the solitonic sector the considerations were so fat restricted to the study of the properties of the classical solutions. The quantization of the chiral Nambu-Jona-Lasinio soliton, built up from both valence and sea quarks, was formally performed in a cranking type approach in Refs. [2,3]. This approach is numerically applied to the selfconsistent numerical solution in order to investigate for the first time the properties of the quantized chiral Nambu-Jona-Lasinio soliton. To this purpose we will calculate the (iso-) rotational moment of inertia with full inclusion of the Dirac sea. With the moment of inertia at hand various properties of the nucléon and delta ate evaluated and compared with experimental data. We consider in the following the two-flavor Nambu-Jona-Lasinio lagrangian 2 LNJL = '^ÛxE)e-^MxE), (2) where ^n(^) is any complete set of eigenfunctions. The formalism for the quantization of the chiral soliton of the proper time regularized action (2) leads to the following expression for the moment of inertia: 0 = QVAL + QSEA , (3) with 347 N, 24 3 rc £ e" ~TC le-"»-ę- "' n + (5) r P? - A Fig.l shows the mass of the nucleon and the delta isobar. They are obtained from the classical energy EQ by E^ = EQ + ^ and JBA = EQ + j^. Apparently, in the relevant region they are too large by about 300 MeV. It is hoped that center-of-mass corrections and pion loops or the inclusion of vector mesons provides an improvement (see [6] for more details). We can summarize: The selfconsistent solution of the Nambu-Jona-Lasinio model was quantized serniclassically. By this the (iso-) rotational moment of inertia, the nucleon-delta splitting and the masses of the nucleon and delta were evaluated for the first time and the rotational properties were studied. It turns out that for the selfconsistent solutions the experimental nucleon-delta splitting is reproduced if one uses small constituent masses in the region M = 350-420 MeV. In this region a clear valence quark picture persists with only 20% contribution of the sea quarks. The absolute energy of the nucleon comes out too high by about 300 MeV. Fig.l Eneigy of the nudcon (bold lolid line), delta (thin tolidline) and the non-qaantined hedge- hog (mean-field [1] J.Nambu, G.Jona-Lasinio, Phyt.Rev 122 (1961) 345. [2] D.Dyakonov, V.Petrov, P.P^bylitsa, Nuct.Phys. B306 (1988) 809. [3] H.Reinhardt, Nucl.Phyc. ,*.5O3 (1989) 825. [4] D.Ebert, H.Reinhardt, Nucl.Phys. B271 (1986) 188. [5] J.Schwinger, Phys,Rev, 82 (1951) 664. [6] K.Goeke, A.Z.Górski,F.Grummer,Th.MeiBEner, H.Reinhardt, R.Wunsch, Phys Uit. B256 321, (1991). 348 Nucleon electric form factors in the chiral soliton model: the one-quark loop £l"f~ approximation K.Goeke1, A.Z.Górski, F.Gruiruner1 1 Theoreti$che Physik II, Ruhr-Universitai Bochum In this paper we compute the isoscalar and isovector nucleon charge densities from which we can obtain the neutron and proton charge densities as simple linear combinations. With these fundamental objects at hand all electric properties of the neutron and proton can be evaluated and compared with experimental data. In particular, we present proton electric form factor. We start from the model and regularization as in the previous report (see also [1]). The diagonalination of the Dirac operator is done following the method of Kahana and Ripka [2]. In this way we can compute physical observables without recourse to the derivative (gradient) expansion. Having the eigenfunctions and eigenenergies as the next step we calculate the corresponding charge densities and the Sachs electric form factors defined by: , (1) The formula (1) is valid in the non-relativistic region, for q2 smaller than the nucleon mass (MN) squared, i.e. below 1 GeV that is just the case of our interest. In order to compute these matrix elements one has to couple the quark fields in the Dirac operator to the external electromagnetic field Ap. The coupling term is: fpA^Q, where Q = |l + \T~Z- TO take into account the vacuum polarisation effects (quark 1-loop correction) we consider the rotating soliton introducing the angular velocity matrix £1 £ SU(2) [3]. Thif produces one more extra term in the Dirac operator that, in the Hamiltonian form, reads: (2) with the Hamiltonian h = 747* d — 74 U, where R(t) is the operator generating the soliton isorotation: R(t) — exp[-iftt] and U = a + 175 rA xA. Finally, in the Dirac operator we have two additional types of terms: the electromagnetic coupling terms (yl^-terms) and the collective coordinate or cranking fi-terms. The current in (1) is defined as the variational derivative of the action with respect to the external field A^ taken at the point Ap = 0: To compute this quantity explicitly, first one has to make expansion of the action in terms of the 0. and ^4^,. To this end we apply the famous Feynman-Schwinger-Dyson expansion for an operator exponent in ihe aciicn. As the second step, we perform the variation:.! ....•- (3). The only non-zero contribution comes from the terms linear in -Ap and all other terms can be ignored. Then we cut the expansion at the first (linear) order in 0, assuming small rotational velocity (that is, in fact, of the order of 1/NC). Now, taking eigenfunctions of the unperturbed Hamiltonian allows us to substitute tńe Hamiltonian operator h by its corresponding eigenenergies ert- Using the definition (1), after some algebra, we are able to write down the nucleon isoscalar and isovector Sachs form factors in the following compact form: 349 2 E (^)| } , (4) where / is the moment of inertia computed previously [1], Nc is the number of colours (JVC = 3), and summation is assumed over repeated index A. The valence level is denoted by VAL. The index ALL refers to a sum over all eigenlevels including the valence one. The deiails of these calculations will be published elsewhere. The proton form factor is shown in Fig.l. It is given in the region q2 < Mjf for which our assumption that recoil effects are small might be justified. Apparently, the proton form factor is in good agreement with the experimental data and also not very sensitive to the actual choice of M, if M is choosen around 400 MeV. For the neutron form factor, which is a difference of two large quantities, the < niribute up to 30% and the result of present calculations is not very reli Me. the neuuu., fnr is correctly reproduced only at small momentum transfers. For about q > 400MeV (^ " "^HrV2) our model overestimates the experiment by 30-40% (see [4,5] for more dot- .,,a oi the proton the sea quarks contribute to less than 5% to the electric form JCk. *V MMV 100 OHO Fig.l Th« pioton Utctric fonn lactojt ai a fu- v nction of the iquLrsd momtBtanj tt&nrfu [QeV y oso fcl The i olid line i describe tht total fonafadoi (tkici Ike) the and ie& coninbution (thic liae) for tie coxtHitnent qnaikmaii 363MeV, The daihsdllaei O.'O diiplay the i&me hdbtmatloa for the comiiiutai qu»ik mail 418.5 MeV. Foi the expenmenttil data to) 000 ice [6] and lefeientti t&ciein. [1] K.Goeke, A.Z.Górski, F.Grummer, Th.Meissner, H.Reinh.-.rdf, R.Wun-h. Phys.Lett. B266 321, (1991). [2] S.Kahana, G.Ripka. NuclPhys. A419 462, (1984). [3j D.Dyakonov, V.Petrov, P.Pobylitsa, NuclPhys. B306 809, (1988). [4] A.Z.Górski, F.Griimmer, K.Goeke, preprint TPII Ruhr-Universitdt Bochum(1991), sub- mitted to Phys.Lett B [5] K.Goeke! A.Z.Górski, F.Grummci-, Proceedings Bad Honeff Conference (1991) {6] M.F.Gari, W.Kriimpelmann, Z.Phys. A3?2 689, (1985). 350 INTERNATIONAL CONFERENCES 1. E.Obryk, "Desired Characteristics of Gas-cooled Reactors for Co-generation with Siting in Densely Populated Areas" ,Desired Characteristics for the Next Gener- ation of Gas-cooled Reactors, IAEA, Vienna, 24-28 June 1991. 2. E.Obryk, "Transition to a Market Economy in Poland and its Implications for Nuclear Power Options", 10th Meeting of the International Working Group in Gas Cooled Reactors , Vienna, 30 Sept.-2 Oct. 1991. SEMINARS 1. Z.Chyliński "Historical review of the philosophy of space and time".Institute of Applied Mathematics of the Warsaw University. 2. Z.Chylińaki "Quantum physics and physical reality". Institute of Applied Math- ematics of the Warsaw University. 3. E.Obryk, "Green-house Effect - Feara, Hopes and Uncertainties", Silesian Divi- sion of the Polish Academy of Sciences. 4. E.Obryk "Helium Cooled High Temperature Reactors and Their Utilization Possibilities", Committee of Energy Problems, Polish Academy of Sciences. 5. E.Obryk, "Global Threats: Ozone Hole and Green-house Effect", first lecture in the Beries of lectures on Ecology, Cultural Centre HTS, Cracow. LECTURES 1. Z.Chylinaki, Lectures in the Faculty of Philosophy of the Jagiellonian Univeroifcy on the "Evolution of Physical Concepts". In two parts: Part I - "From Ancient Greek to Modern Physics". 28 hours of lectures and 28 hours of seminars.(First semester) Part II - "Modern Physics". 28 hours of lectures and 28 hours of seminars. (Second semester). 2. E.Obryk, "Energy and Environment", 12 hours, Academy of Agriculture, Cracow, (postgraduate studies). 351 PUBLICATIONS 1. Z.Chylińaki, "Quantum and Relativistic Physics — Relationism and Relativism" (book, in Polish). To be published by M.Kudelska and M.Kalmus, Cracow. 2. 'LChylińeki, A.Dunlop, J.Mory and A.Pathak, "Dechanneling Cross-section of or-Particles by Interstitial Atoms in Palladium", Nuclear Instruments and Methods (to be published). 3. K.Goeke, A.Z.Górski, F.Grummer, Th.Mehsner, H.Reinhardt, R.Wunech, "Quantization of the Nambu-Jona-Lasinio and the nucleon-delta splitting", Phys. Lett. B 256 (1991) 321-324. 4. K.Goeke, A.Z.Górski, F.Grii/nmer,"Nucleon electric form factors in the chiral aoliton model: the one-quark loop approximation", Conf. Bad Honeflf. Proceed- ings (1991). 5. A.Z.Górski, K.Goeke, F.Grummer, "Nucleon electric form factor and quark sea polarization in the Nambu-Jona-Lasinio model", preprint TPII Ruhr- Universitat Bochum (1991). 6. E.Obryk, "Status of HTGR activities in Poland", Summary Report of Nineth Meeting of the Intel-national Working Group on Gas Cooled Reactors, IAEA, Vienna 1991, p.46. 7. E.Obryk, "HTGR — application potentials and development perspectives", Archiwum Energetyki (accepted for publication). 8. E.Obryk, "Desired characteristics of gas-cooled reactors for co-generation with siting in dencely populated areas (to be published by IAEA). 9. E.Obryk, "Transition to a market economy in Poland and its implications for nuclear power options" (to be published by IAEA). 352 Department of Radiobiology DEPARTMENT OF RADIOBIOLOGY 1. STAFF Permanent staff Jolanta ADAMCZYK Edward DYRSKI Antonina CEBULSKA• WASILEWSKA* Janusz GAJEWSKI Jerzy HUCZKOWSKI** Barbara JAN IS ZEWSKA Tomasz JANISZEWSKI Ewa KASPER Stanisław KRASNOWOLSKI Bogusława KRZYK WA Krystyna KULCZYKOWSKA Małgorzata LITWINISZYN Barbara ŁAZARSKA*** Monika MOSZCZYŃSKA Barbara PAŁKA Janusz SMAGAŁA Anna WIERZEWSKA Joanna WILTOWSKA * Head of Laboratory Radiation and Environmental Mutagenesis + * Head of Department till 30.06.91 ++* Head of Department and Laboratory Neutron Therapy and Applied Radiobiology in Therapy and Agriculture 353 2. FOREWORD The research program in the Department of Radiobiology is performed by two Labo- ratories: 1. Laboratory of Neutron Therapy and Applied in Radiobiology Therapy and Agriculture 2. Laboratory of Radiation and Environmental Mutagenesis Our work is the radiobiological bases for a short course neutron therapy (5 fractions in 5 days) in Cracow. Vast experimental material which recently been collected in cooperation with Gray Laboratory in London is now being analysed. Results obtained concern the early effect of irradiation with fraction neutron and X-ray doses on foot skin and the retarded effect on kidneys and lungs in mice. Our aim was to determine the Relative Biological Effectiveness (RBE) of fast 5.6 MeV neutrons with regard to regime of fractionation. Previous findings suggest that changing the regime from 20 to 10 and 10 to 5 fractions does not significantly affect the reaction of healthy tissue studied. Hence reducing the neutron therapy to 5 fractions in 4 days makes possible increasing the total dose, which improves the overall effect. The Institute of Oncology in Cracow has been following just this procedure. In 1991 year 42 patients underwent one week treatments of that kind. In the same year new experiments were initiated in cooperation with Institute of Oncology in Cracow (prof. J. Skołyszewski) and Clinic of Radiotherapy of Saint mary Hospital at Portsmouth in England (prof. V. Svoboda). This is a comparative study of X and 7-rays fractionation on various animal model system. Early effect skin and retarded effect on lungs and kidneys are compared with those from former studies. Pilot experiments were performed on a newly available mouse line C3H, whose radiosensitivity is higher of the CBA line than that prevoiusly used. In cooperation with Academy of Agriculture in Cracow we have been conducting research on the mutagenesis in rape-seed in vitro regeneration of dihaploids and pollen grains. The object is to find how much fast neutrons, X and 7-rays irradiations stimulate the dihaploide production and to determine their reaction in flower buds microspores and anther cultures. One of the consequences of the polluted environment is the growning risk that the physical and chemical mutagenic agents introduced to the environment may affect the prresent and future generations. Our Laboratory of Radiation and Environmental Muta- genesia has been carrying out research on: 354 - dose response relationship for the mutagenic effects of: ionizirg and nonionizing radi- ation and chemicals, - the influence of non-mutagenic (anti or promutagenic) elements in the environment on the frequency of mutations induced by mutagenic agents, - interactions between various mutagenic nonmutagenic agents, - biological monitoring in situ. In our studies we have used various bio-assays, among them a test based on mea- surements of somatic mutation frequency in Tradescantia (TSH). This test is marked by exceptionally very high sensitivity to radiation and chemical mutagenic agents. Because of its advantages and high sensitivity TSH was promoted to the international collaborative study on the utility of plant tet.t systems in genetic toxicology. Under the sponsorship of the UNEP/ILO/WHO International Programme on Chemical Safety our laboratory was participating among 6 international laboratories in evaluating inter and intralaboratory variabilities of the bio-assay. The preliminary results revealed that those variabilities were relatively lower then in the most commonly used bio-assay based on Salmonella. Head of Department dr Barbara Lazarska 3. ABSTRACTS Application of Modified Radiation Dose-Response Curves Analysis for Studying Environmental Agents A. CEBULSKA-WASILEWSKA The radiation dose response curve for somatic mutations in Tradescantia is well fitted to the linear quadratic equation describing biological effects in terms of the molecular theory of radiation action, defined according to Chadwick and Leenhouts (Chadwick and Lcsnhouts 1980) as follows: M = 1 - exp[-q(aD + {3D2)exp[-{s + p)(aD + 3D2)] where: M = mutation frequency, D = radiation dose in Gy, a, /? = probabilities per unit and square unit dose that DNA double strand breaks (dsb) are induced in one (a) or two simultaneous (/?) energy depositions, q = probability that radiation-induced DNA dsb 355 leads to a specific mutation, s = probability that induced DNA dsb leads to the suppression of a specific mutation, p = probability that DNA dsb leads to cell reproductive death. , „ » Figure la demonstrates how the dose response curve obtained from the best fit of .our experimental data to this equation, changes with altering the characteristics of radiation. Fipu-es lb shows the same in those cases where repair processes of induced DNA lessions in the cells were changed. Experimentally modified by environmental agents dose-response curves were analyzed according to this linear quadratic model. Observed modification of dose- response curve obtained after sodium fluoride pretreatment suggest that fluoride pretreatment might disturb repair processes of the DNA double strand breaks By contrast enriching substiade with ions of magnesium and calcium by admixture of dolomite into the soil lowers the radiosensitivity of the plants. The alteration of the dose response curve when magnesium and calcium levels were raised by dolomite admixture to the soil, suggests that Mg/Ca ions may ^iuence processes of induction or repair of the radiation-mduced DNA single strand breaks. ,p ,q ,s constant constont *• 0 2.5 5,0 7.5 W.O 250 5.00 7.50 10.00 Dose (Cyl Dose(Gy) Fig.l. - Influence of physical (a), and chemical (b) characteristics of environmental agent interacting with radiation on radiation dose-response relationships. Analysis of modified by environmental agent radiation dose response curves helps to understand a mechanisms of environmental agents action to DNA. The sensxtivity of TSH. system allows to study also mutagenicity of chemical pollutants in the environment. The utility of this system in genetic toxicology was proofed in the international collabora ive studies under the sponsorship of UNEP/ILO/WHO International Programme on Chemical Safety in which our Laboratory had participated (Fig.2). Those facts together make the TSH system particuhry useful for studying environmental agents. 356 10' T • UJO CRACOW i 10' r 10 10' to' 10' ttpawr Uonttntralion * ttmrl IV.'hi Fig.2. - Pink mutation frequencies obtained in the IPCS studies of coded chemicals and carcinogens Comparison Between Chemical and Biological Monitoring of Ambient Air Pollutants Mutagenicity with Tradescantia Stamen Hair System A. CEBULSKA-WASILEWSKA, J. PAWLOWSKI1 1 Environmental Protection Laboratory MZRiP, Plock Several times since 1983 groups of plants of Tradescantia clone 4430 have been exposed to ambient air on various sites of the Cracow area and in the vicinity of petroleum industry in iae Plock. The highest value of mutation frequency was noted in May 1986 after the Chernobyl accident (Fig.l) A slightly lower level of mutation frequency but comparable in value, was reached in the year 1991 at the site of public elementary school in the street 357 cross lights neighborhood, and in 1983 in vicinity to a pharmaceutical factory (Table 1). In various periods of 1987 temporary differences between the levels of mutations were observed on various sites in Cracow. During the period of examination, they range from 0.09 to 0.31 mut/100 hairs, and they revealed a correlation between the mutation level and the SO2 contents in the air. In two periods of 1991, the T3H bio-assay was applied for detecting an ambient air mutagenicity in the city Plock area. There were differences between the levels cf mutations observed on various sites in the city and in the vicinity of petroleum plant (MZRiP). Pink mutation frequency appeared to be only slightly dependent on the distance from the petroleum work' center (Fig.2). Mutation frequencies fitted well with chemical measurements of concentrations in the air, and revealed that points were weakly influenced by the works emission. Therefore, it appears that actually communal and transport pollution in the city center contributes to the final biological effect and can play an important role in physiological cellular processes (Fig.3). The frequency of mutations due to exposure to air in the vicinity industrial installa- tions in the course of our research have been as high as those occurring after irradiation of the plants with doses of radiation exceeding by many orders of magnitude the standards made acceptable for humans. The order of the effects observed in the studies of ambient air pollutants mutagenicity are equal to biological effects of the radiation dose of 0.05 Gy. Those effects sometimes exceed those induced by doses received by population after serious nuclear accident like Chernobyl. This fact is very important because public opinion very often is strongly against the radiation risk, sometimes ignoring completely a much higher everyday risk coming from highly mutagenic chemical pollutants present in the environ- ment. Strong association between mutagenic potential and carcinogenic potential makes those results important for genetic risk assessment and environmental protection field. Table 1 Mean value of mutation frequencies detected by TSH assay in different periods and places Site Period NOH mut/100 Rad-equiv. tested hairs +SB (Gy) Cracow June 1983 81517 0.39 + 0.009 0.05 May 1986 10259 0.43 -f 0.025 0.06 June 1987 117477 0.19 + 0.07 * (a) May 1991 47473 0.40 + 0.025 0.05 00 30316 0.28 + 0.026 0.02 (c) 22615 0.20 + 0.010 0.002 Płock j (d) June 1991 117679 0.36 +0.007 0.03 105400 0.25 + 0.007 0.02 NOH - number of hairs, * - level taken as a control value, (a) - elementary school No.12, (b) - distance ~ 250 m from school, (c) - Inst. of Nuclear physics (d) - petroleum plant center, (e) - city center 358 Tradescantid U30 9=0.^310.02 ?gt0,09i0.02 w 0.6 0.6 OA 20,04 0.2 JL r T t,tift7 W 15 20/0f ••II ' i i i i i < i • i i i t i i i 30/0 i 5 10 15 20 P5/05 10- S W 3 : UA3TT-..,,,. ł l' L I 1 I I i I • • i i • •!<• i i i i i i // '••'!•! JS Jir J9fii4 Vce 3 3 s s r i i » nn u13 a is trn it ls „ 1IHC Fig.l. - Time dependent development of mutation frequency in TSH and air radioactivity after Chernoby] accident 359 PŁOCK yjiU52-0.0Ubx '.'.-0JJ8-0.0WX J Ł o I stage I « II stage UJ a OL u. o 0.2 0. '2 34 56 769 10 DISTANCE FROM THE MZPRP PLANT CENTER Fig.2. • Influence of the distance from the work's center on mutation frequency induced in TSH assay V) CL 0 35 i • - Stunted lialrs 4 "- ceLl cycle facto INO O 4- colorless : f t> O o.io a. OJS 0 ]0 -ł-.-«- r W 20 30 (O 50 „g/m* 000 ""**Vobó • 7000 woo PHENOL (q/m"3) x 10<«-3 CONCENTRATION SOJ Pig.3 - Correlations between various biological end points measured by TSH system and chemical's concentrations in the air. 360 Mutagenicity of Pesticides Studies with Different Biological Assays A. CEBULSKA-WAS1LEWSKA, H. PIVCIENNIK llo Studies on genotoxic effects of different herbicides and insecticides were performed with applications of several bio-assays. The somatic mutations in Trade3caniia, chlorophyll mutations in Cklorella v. mitochondrial mutations in Saccharomyccs cerev., were used for an estimation of the mutagenic efficiency of several preparations. Our studies were focused on the mutagenicity of preparations currently used in the agriculture of southern Poland. The preparations were selected according to suggestions from the Centre for Plant Protection in Krakow. Some of the agrochemicals like " Aminopielik", "Decis" and their biologically active compounds: 2,4 D and deltamethrine respectively, revealing the mutagenic activity in at least two tests out of the three made, were additionally studied for its interaction with the ionizing radiation. Table 1. Mutation frequency (%) induced on LD&Q level in various bio-assays Chlare.Ua Saccharomy- Tradescantia V, ces cerev. X-rays 0.13 2.63 45.0 2.4 D 0 0 nt Aminopielik 88 0.0075 0.91 11.71 Aminopielik 89 0 0 2.02 Afalon nt nt 2.5 Afalon (2 y) nt nt 29.46 Ambusz 0.0018 3.8 2.74 Decis 0 0 0.55 Deltamethrine 0 0 12.03 Bi-58 nt nt 0 Prometan nt nt ? Ripcord nt nt 18.09 Tiuram 0 0 nt EMS 0.12 nt 17.85 Acridine nt 0.32 nt nt = not tested The comparative studies of the mutagenic activity were performed for the well known mutagenic agents like EMS, and ionizing radiations, in all bio- assays applied. Mutagenic 361 effects estimated on the LD$o level were used for ilustrating mutagenic activity of the inves- tigated agrochemicals (Table 1). Most of those preparations which revealed mutagenicity when tested with TSH, showed their synergism with ioninzing radiation. The occure of synergism in mutations is of great importance for the environment at risk, as it is always the case that more than one mutagenic agent is present and active in the environment. The additional biological effect due to the synergistic interaction has been found to be comparable to the effect of chemical mutagenic agents acting separately, and in some cases to be even stronger. The close links between mutagenic and carcinogenic properties lead to the conclusion that similar effects and dependences are to be expected in the case of stimulation of growth of cancer cells. It is clear, therefore, that all such effects ought to be taken into account in determining the acceptable levels of pollutions. T' 4430 RIPCORD 40 PC o ripcord * X-rays • X-rays 12 // synergism \ 10 o % o 1 1 20 40 60 80 100 (cGy! Radiation dose Fig.l. - Synergistic interaction in the induction of somatic, mutation in Tradescantia 362 Table 2. Somatic mutation frequencies and Rad-equivalents for effects induced by preparations in- v«st,igji.f.fMl with TSH assay Sample Exposure Pinks freq. Ratl-oqv. mut/100 hairs cGy X-rays 1 cGy 0.045 1.0 (rad) EMS 20 fi - 0.045 % 0.60 13.3 Aminopielik 88 10 /t - 0.004 % 0.30 6.7 Aminopielik 89 10 n - 0.004 % 0.24 5.3 Afalon (2) 10 n - 0.003 % 0.27 7.3 Afalon (0) 10 /i - 0.003 % 0.33 6.0 Ambusz 10 fi - 0.005 % 0.30 6.7 Ripcord 10 fi - 0.0005 % 0.17 3.S Decis 10 n - 0.1 % 0.01 0.2 Deltamethrine 2 mg/lOml DMS0 0.26 5.8 The results obtained with TSH system make it possible to compare the effects of the studied solutions with those of radiation. The values of Rad-equivalents for the studied substances are usually high. Thus, in some biological systems common agrochemicals may prove more mutagenic Mian well known strong mutagens. Some of the agrochemicals become highly mutagenic <' pending on the storage time (Ambusz) or technological series ("Aminopielik"), Rad-equivalents calculated for biological effects in Tradescantia caused by mutagenic agrochemicals at the concentrations similar to those applied in a practice, greatly extend the permissible annual effective dose. Comparison Between Mutagenicity of Some Herbicide and Radiation in Tradcacaniia and Human Blood Lymphocytes Assays A. CEBULSKA-WASILEWSKA, A. WIERZEWSKA, E. KASPER, D. KRZYKWA In Poland, as everywhere in the world, the range of chemicals introduced into the en- vironment is continuously increasing. Although some of them, like pesticides, improve the quality of crops, but some of these substances are potentially dangerous to the environment nnd human health. Their damaging cons. -^lences may include a higher frequency of cancer colls, hereditary genetic disturbances, oi &.o-called genetic drift. That is why Jtudies which 363 yield new information on carcinogenicity or inutagenicity of popular chemicals or prepa- rations are gaining in importance. In this paper we present our results of the studies of inutagenicity of ionizing radiation and chemical mutagen (Amincpielik), tested by two dif- ferent bioassays: somatic mutations in Tradescantia (TSH) and chroi \some aberrations and sister chrornatid exchange in human blood lymphocytes (Figs 1 and 2). Comparison between biological effects observed in bovh assays (one based on TSH and another one on the human blood lymphocytes) showed that cells of the Tradescantia and human blood lymphocytes have very similar sensitivity to diferent types of ionizing radiation (neutrons and X-rays). Our results suggest also that this similar sensitivity to radiation is followed by similar sensitivity to chemicals (Fig.3). TRADESCANTIA LYMPHOCYTES 10 T X-RAYS PINK MU1A1ION5 ~ too- . BNL DOSE RATE 110 9 : o in c. 3 • \ I 8 i.o X Ul z o < I- 5: J 001 ~~*rtT*T-r 10 0.10 1.0 10 100 X-RAY DOSE UGy] DOSE Fig.l. - X-rays dose response relationships: (a) in TSH, (b) in human blood lymphocytes 364 LYMPHOCYTES 10 1 TRADESCANTIA NEUTRONS Z = 5.6- MeV UJ a l I 10 0 8 in z o i '0 •z ft 0.10 -f • t > . r,,,r 10 '"! r r-i-rrmi 010 10 "1r0 ' 100 1 10 10' • 10' 10' 56-MeV NEUTRON DOSE ItGyl DOSE C CGY] Fig.2. - Neutrons dose response relationships: (a) in TSH, (b) in human blood lymphocytes. /"-44J0 AMItJOPIEUK (OOOr/.l LYMPHOCYTES J 06 UJ < lib a X u o 0.J z 5 o < 5 UJ CD L1-J.ŁJ. < 700 300 10 30 o.ro 1.00 Fig.3. - Chemical dose response relationships: (a) in TSH, (b) in human blood lymphocytes 365 It is important that the limited resources available are focussed on first realizing ma- jor genetic and or carcinogenic hazards. So, correlations of experimental genotoxicity data for chemicals are important and searching for correlations between evidens of induced geiiotoxic damage in exposed living organisms or human with accurate measures of 3 ex- posures, will enable progress in total environmental quality. Further, use of biomonitoring techniques associated with a simple methods like plant systems are an essential component of a cost-effective attempt to improve the situation. Summing up, existence of correlations between physical measurements and biological end-points in somatic mutations in TSH as- say from one side, and similarity of the responses of TSH system to physical and chemical mutagens with the response of human blood cells from other side becomes an additional proof showing how sensitive and relevant the Tradcscantia method is. EDTA Renal Clearance and Urea, Creation and Haematocrit Levels in Blood Observed in Mice after Bilateral, Local Irradiation of Kidneys /. HVCZKOWSKI, R. KOZIEJKO l, S. KRASNOWOLSKI, K. KVLCZYKOWSKA B. ŁAZARSKA, M. MOSZCZYŃSKA The Rydygier Spccialistic Hospital in Cracow In cooperation with Gray Laboratory in London (Gray Lab. Ann. Rep., 1989, p.53) bilateral lokal kidneys irradiation has been performed on CBA line mice. Fractionated X-rays and the neutron beam from -120 cyclotron were used. The goal is to determine the effect of total and fractionated doses on Relative Biological Effectiveness (RBE). Our points of reference were Gray Laboratory test results in lowering the Cr51 EDTA renal clearance and lowering the haematocrit level in blood. The value measured was the level of Cr51 marked EDTA the renal clearance observed in the serum one hour after the injection of the Cr51 into the blood circulation. Detailed results will be presented in a separate publication. We have performed additional measurements of urea and creatinin levels in serum us- ing the tests for the determination of renal damage in clinical patients (K. Kulczykowska), Our results are from research on X-rayed CBA line mice: 2 fractions (7 days interval), 4 fractions (2 days interval) and 8 fractions (1 day interval). Measurements were performed 42 - 48 weeks after irradiation. 366 hoemalocr it-control £' IB™—control . i/f'fo .- 15 50 *= Fig.l Dependence between dose and level of urea (M), creatinin (K), haematocrit (H) activ- ity EDTA marked Cr (CV51) in the blood for the mice irradiated. 2, 4, 8 the number of the fractions. Conclusions : The curves illustrating the EDTA and urea levels in the blood are almost identical and confirm the well known quasi-threshold sigma relation between dose and reaction. Thus each of the two parameters adequately describes the post irradiation kidney damage. Decrease the haematocrit and increase the creatinin levels are directly proportional to the dose. The fractionation effect of the first 3 tests (EDTA, urea, haematocrit) if? similar which is unlike that of creatinin: here of 2 makes possible administrating 4 fractions instead a slight increase in dose with 8 fractions the increase can be much larger. In consequence with the dose per fraction below a certain volume, the past irradiation kidney damage significantly decreases. 367 4. PUBLICATIONS [1] ML.I. Done, A. Cebulska-Wasilewska, R. Kallman: Interlevkin-1 Modification of ihe Effects of Cyclophosphamide and Fractionated Irradiation , Int. J. of Radiation On- cology, Biology, Physics 20 (1991) 311 [2] B. Lazarska, A. Szkatuła, M. Kopeć: Wpływ wody uzdatnionej magnetycznie na uprawę warzyw szklarniowych (Influence of Magneticaly Treated Water on Cultivation Vegetables in the Green-House), Hasło Ogrodnicze 12 (1991) 14 5. CONFERENCES AND SEMINARS A. CEBULSKA-WASILEWSKA 1. XXth Annual Meeting of EEMS: Environmental Mutagens and Carcinogenesis , Praga, 1991 Paper presented: A. Cebulska-Wasilewska, H. Płuciennik: - Mutagenicity of Pesticides and Radiation Studied with Different Biological Assays. B. LAZARSKA I. The Second INR International School on Nuclear Physics: Radioactive Beams and Their Applications, Kiev, 1991 6. HABILITATIONS Antonina CEBULSKA-WASILEWSKA - Mutagenic Effectiveness of Ionizing Radiation, Chemical and Environmental Mutagens in Tradescantia - Wydział Biologii i Ochrony Środowiska Uniwersytetu Śląskiego, Katowice, October 27, 1991 368 7. LECTURES ]. Dr B. Lazarska - Radiobiology Related to Agriculture, ~ lectures for undergraduate students of Plants Breeding at the Academy of Agriculture, Cracow, April 1991 Invited Conference Lectures Doc. dr hab. A. Cebulska-Wasilewska - plenary lecture: Do Chemicals Bring to the Environvient a Higher Hazard than Radiation ? - VII Annual Cytogenetic Meeting of Polish Genetic Society, Kazimierz n. Wisla, May 1991 Doc. dr hab. A. Cebulska-Wasilewska - Mutagenicity of EMS and Coded Mutagenic Chemicals in Tradescantia Stamen Hair System, UNEP/WHO/LWO Experts Meeting on the Final Results of IPCS Collaborative Studies on Plant System, St. Petersburg, December 1991 8. VISITING SCIENTISTS Prof. VIA DO SVOBODA - St. Mary Hospital, Portsmouth, United Kingdom, June 1991 369 Department of Acceleration Technique "i; Y/J. '} * f i , , DIVISION: NZ-XII Report on Works Performed by the Acceleration Techniques Division in 1990/1991 Experimental works were carried out on the prototype of the isochronous cyclotron type AIC- 144S. Components of the extraction system and of the acceleration process automatic control system were designed and constructed. In the first case the following works were performed: A. Optimization of the beam acceler- ated conditions. B. Beam extraction and its optimization. In the second case software and hardware works connected with: a)automatic tuning of the cyclotron modes b)quality control of the accelerated beam c) control and stabilization of H.F.systems d) safety systems were carried out. Among those a computer controlled IŁF generator type MBC was built and primarily started up and tested. A. Optimization of the accelerated beam [1,2,3]- As is commonly known, acceleration in low energy range is a big problem, in the case of isochronous accelerators working with variable energy. This is caused by active resonance zones which ate present in the beam acceleration low energy (especially active resonances are: non-linear, of the 4-th order, coupled 2QZ - Qr = 0 and parametric Qt — 0.5) - where QliT are amplitudes of betatron oscillations. These resonances cause severe beam intensity losses or its complete decay. This problem, was examined very carefully, experimentally and theoretically. The aim was to determine the conditions of beam passage through these zones with minimum intensity losses. As a result of these works, the lower energy limit of accelerated particles was significantly decreased (from 18 to less than 10 MeV/nucleon). Conditions of beam passage through the nonlinear resonance zone defined by: AQr = 1.0012 ±0.001625 Ail = 22 4- 25 cm INI ERNAL BEAM IS cond :V«ro-80 VJaro-,26 A. AIC-m s BF oOnd;VdOO-»0 KV.DF-0.16 na K 6 HI Qr = (m - k)Njq = 1, for m = 0, Tk-22 MEV AT RK-03 cm FO roeoa MHz. ima-1916 A lti<«im "N" - number of the magnetic spi- NL rals; "k" - number of the higher har- A V \ monics of the Mathieu function; "p" - number of the unstable area of the •V j Mathieu equation; "g" - order of the o io 20 ao 40 GO eo 70 nonlinear resonance. flg.1 RADIUS (CM) Influence of these effects on beam in- tensity, as a function of the acceler- ation radius and its value after the correction is shown in fig. 1. 371 B. Beam extraction from the AIC-144S cyclotron [4,5] Experimental and theoretical works were carried out with the DfinACTlÓN ISO M»v'(d),l«l=O.r.i/V ~/U.OS>.!H use of the following systems: 1) electrostatic system com- prising: exciter, compensator, deflector 1,2 and 3, fig.2 & 3 2) magnetic system consisit- ing of two magnetic channels, fig.3 & 4 3) complex system composed of: exciter, magnetic channel 1, TflRCET 5(OS Crt) deflector 2, magnetic channels 2 and 3, fig.2 k 4. 1. Electrostatic system (ESE): a beam extraction efficiency of = 1 EP3=0 60 - 75% is possible, when the fig.2 following conditions are met: a) good symmetry of the output orbits; b) high voltage on the deflectors (75 - 80 kV); c) orbit seperation > 90%; d) efficient cooling of the electrodes when beam intensity > 100/iA. There are technical problems to fulfill these requirements. This extraction system allows however the smallest deformation of the output radial emittance and the extraction with a minimum energy spread (one turn extraction) to be achieved. Further work is under way. In this case a passage of the beam through DEF. Ife2 (fig.2) was achieved, the extraction factor being approximately 65%. 2. Magnetic system (MGE): the beam was extracted, whim its RADtM. EkłTTANCg EXTT1ACTIOII ! (IIC-111 S asymmetry in relation to the mag- EIECTIW1ATIC SVSTCM netic field symmetry axis was big (> 15%). Extraction efficiency was ca 25%. Extraction factor r\ de- pends on the method of orbit seper- ation. Orbit splitting and simulta- neusly orbit precession was obtained due to the utilization of the nonlin- ear resonance effect in the region of the magnetic stray field (n < 0), see fig.2. A second splitting of the ex- tracted beam can be observed in this figure. About 20% of the beam re- turns in the direction to the equi- librium orbit and is lost on the cy- Fig.3 clotron components. This effect is clearly shown on the radial emit- tance diagram given in fig.4. Analysis of this phenomenon shows that extracted particles having a negative direction in relation to the equilibrium orbit have this tendency. The extraction factor TJ was increased by lf>% after deflector 2 was added, fig.4. This sj'stem however causes a big deformation of radial emittance at the output of the cyclotron. 372 3. Magneto-Electrostatic System (MGES): This system turned out to be the most promising, fig.3. It can hiivu different configurations. Its optimization proved that the fol- lowing set is the best: exciter, compensator, MGC1, DEFL2, MGC2, MGC3. This configuration does not require any critical condi- tions to be met, such as: rwcrcuc cnr*L a) orbit symmetry (£ < 10% ), perz -rcFiECum 2 b) high voltage: Vd < CO fcV, V„e < 20 kV, Vcatn = 15 kV. 78 82 c) electrode cooling as Experiments were performed with- out a compensator and a correction magnetic channel (MGC3). Due to the resonance excitation, an extrac- tion efficiency of 25-30 % was Fig.4 achieved. A second beam splitting was not observed. Loss of the extracted beam did not exceed 10%. Measurements have shown, a 40 •- 50% beam extrac- tion efficiency is possible, if excitations of coherent os- cillations in the beam were additionally utilized [5] and resonance exitations in rela- tion to the extraction sys- tem were precisely located. Further works on extraction beam optimisation are under way. The cross section of the beam on a plexiglass plate placed in the outlet of the output chamber is shown in fig-5. References Fig5 [1] J.Schwabe ct al., Start-up of the isochronous cyclotron AIC-144 on its internal beam, INP Report No 1506/P£ [2] J.Schwabe and H.Doruch, Conditions of accelerated beam optimization in the isochronous cyclotron AIC-144 Sigma, INP Report No 1508/PL [3] Schwabe et al., Specifications of the isochronous cyclotron AIC-1445 during its start-up on the internal beam, INP Report No 1507/PL 4 INP Report (to be published) 5 K.Daniel, J.Korecki, High voltage power supplies for the extraction system of the AIC-1445 cyclotron, INP Report No 1530/Pi [6] J.Huczkowski,A.Kolaczkowski,J.Mikulski,J.Schwabe, Isochronous Cyclotron AIC-144. Main Parameters, Aplication Possibilities, INP Report No 1480/ PL 373 Health Physics Laboratory s. 4 •!•> < nj HEALTH PHYSICS LABORATORY Head of Laboratory: Docent dr Tadeusz Niewiadomski (until Dec.31 1991) Docent dr Michał P.R. Waligótski (from Jan. J 1992) OVERVIEW: The activity of the Health Physics Laboratory of the Institute of Nuclear Physics is prin- cipally in research and routine work in the general area of radiation protection. Experimental research concerns solid state dosimetry (mainly thermoluminescence dosimetry) and environ- mental radiation protection (assessment of the radiological hazard from coal-fired power plants and from radon in dwellings). Theoretical research concerns radiation physics, radiation protec- tion (modelling radiation effects in biological and physical systems) and studies of concepts in radiation protection. The Laboratory provides expert advice on national and international ra- diation protection regulations to other INP laboratories and at a national level. Over the years, considerable expertise in TL dosimetry has been developed in the Laboratory: TL detectors, based on LiF (Mg, Ti-doped, equivalent to HARSHAW TLD-100, TLD-600 or TLD-700, and Cu,P-doped, equivalent to ultra-sensitive "Chinese" phosphors) are produced, as well as TLD readers, irradiators and annealing ovens. In the recent years, the Laboratory has established an international reputation in trade structure and microdosimetric modelling, for application in radiation protection and theoretical radiobiology. Routine work of the Health Physics Laboratory involves development and maintenance of a personnel dosimetry system (based on TL dosimeters), maintaining radiation safety on INP premises, and supervising and consulting other ENP laboratories on matters pertaining to radi- ation safety. The staff of the Laboratory consists of 12 persons, and includes 1 nuclear physicist, 2 physi- cistsv 5 nuclear engineers, 1 chemist and 3 technicians. Two staff members hold "docent" degrees and have acted as Experts for the IAEA (Vienna) in Radiation Protection, two other hold Ph.D. degrees in Physics, one staff member is the Chief Radiation Protection Officer and two other are qualified Radiation Protection Officers. The Laboratory participates in an official Polish-German Government scientific exchange programme and has many informal contacts with European and US laboratories. Several research proposals have been submitted by the Laboratory to the National Research Council (KBN), which are currently under review. 375 2. DESCRIPTION OF RESEARCH ACTIVITIES 2.1. THBRMOLUMINESCENCE DOSIMETRY The thrust of work in this area in 1991 was to develop a system for measuring personal and ambient doses in stray neutron fields, employing Laboratory-produced °LiF and 7LiF detectors in an albedo-type dosimeter. Parts of this project are carried out in collaboration with KfK Karlsruhe, Germany. Stray neutron fields around a 60 MeV cyclotron under construction at the INP, were monitored, using TL detectors. The response of ultra-sensitive LiF:CuP detectors manufactured in the Laboratory, after a wide range of X- and gamma-ray doses, was measured. Properties of TL phosphors based on LiF have been reviewed, to be published abroad as a chapter in a textbook on TL dosimetry. 2.2. MONITORING OF IONIZING RADIATION IN THE ENVIRONMENT A three-year study of the radiological environmental impact of coal burning for production of energy in Poland, contracted by the Central Laboratory for Radiation Protection (CLOR, Warsaw) was completed. In collaboration with the same contractor, a national programme of measuring levels of Radon-222 in dwellings was initiated. A setup for calibrating radon, cups in our Laboratory has been designed and is currently under construction. 2.3. MICRODOSIMETRY AND TRACK STRUCTURE MODELLING OF PHYSICAL AND BIOLOGICAL SYSTEMS Work in this area concentrated on studying the common theoretical input to niicrodosimetric and track structure model approaches. Monte-Carlo simulations of particle tracks were compared with an analytical formula from track structure theory; identical sets of experimental radiobiolog- ical data obtained from neutron exposures were analysed using both model approaches. Energy deposition in small volumes after neutron exposures was calculated for comparison with mi- crodosimetric spectra measured in an ultra-miniature counter. Model analyses of the response of new types of thennoluminescence dosimeters developed in our Laboratory are under way. Work in this area is performed in close collaboration with the Institute of Medicine, KFA Julich (Germany), under a Polish-German Government Research Project No. X085.4., and under col- laboration with Brookhaven National Laboratory (USA) and the University of Nebraska-Lincoln (USA). 2.4. STUDIES OF INTERNATIONAL RADIATION SAFETY REGULATIONS Laboratory staff were actively engaged in discussion and promotion in Poland of the new recommendations of the ICRP (Publication CO). A Polish translation of the Summary of these Recommendations was made, and a national workshop on the concept of risk in radiation protec- tion organized at the INP. Members of the Laboratory stafl'participated and lectured at several meetings on this subject in Poland, acting as experts to the IAEA and to the National Nuclear Energy Agency. 376 HEALTH PHYSICS LABORATORY STAFF Paweł BILSKI, E. Eng.(Nucl. Eng.)-Radiation Safety Officer Maciej RUDZANOWSKI, E. Eng.(Nud. Eng.)- Radiation Safety Officer Józef DYBEŁ- Technician Mnrta GABRYŚ, M.Sc. (Chemistry) Jerzy 1BK0WSKI - Technician, Radiation Safety Officer Irena LIPEŃSKA - Technician, Secretary Tadeusz NIEWIADOMSKI, Ph.D., Docent (Physics), Head of Laboratory Małgorzata NOWINA-KONOPKA, M.Sc. (Physics) Paweł OLKO, E.Eng.,Ph.D (Physics) - Deputy Head of Laboratory (since Jan. 1 1992) Elżbieta RYBA, E.Eng. - Chief Radiation Safety Officer, INP Michał (Michael P.R.) WALIGÓRSKI, Ph.D., Docent (Physics), Head of Laboratory (since Jan. 1 1992) Piotr WASIOŁEK, M.Sc, Ph.D.(Physics) - on leave of absence to New Mexico In- stitute of Mining and Technology, Socorro NM, USA. REPORTS ON RESEARCH: New TL detectors of stray neutron fields (work in progress) T. Niewiadomski, E. Ryba, M. Budzanowski and P. Bilski A tandem of LiF thermoluminescent pellets, one very sensitive to thermal neutrons (6LiF) and another with a negligible neutron response (7LiF) are typically used in albedo neutron doshnetry. One of the main objectives in this type of dosiinetry is to obtain a high neutron- to-gamma response ratio. This can be achieved by reducing the effective thickness of the 6LiF detector either by lowering the transparency of the pellet to TL light or by making theysensitive TL layer thinner. Two types of detectors: a "thin-layer" detector featuring a thin 9LiF sensitive layer on a LiF non-thermoluminescent base, and an "opaque" detector in which the 6LiF phosphor is mixed with graphite and carbon and sintered, are being developed in the Laboratory. Detectors with different thicknesses of the sensitive layer (50 - 400/xm) and different carbon concentrations (1- 10% ) are being tested in commercial boron-loaded plastic badges of ALNOR, HARSHAW and VINTEN types. The detectors are irradiated with thermalized neutrons from 239Pu-Be and other aouices. Preliminary results of measurements and calculations indicate that detectors of effective sensitive thickness of about 300 fiin exhibit a neutron-to-gamma response ratio larger by a factor 2-4, compared with the standard 800 /xm detector. The new detectors will be used in an improved personal neutron albedo dosemeter with detection limit below 100 /iSv in a gamma-ray background of the range of several /xSv. 377 Radiological hazard from coal-fired power plants in Poland M. Nowina - Konopka (paper submitted to Radiat. Prot. Dosiin.) The aim of this study was to assess doses received by the population, of Poland due to coal combustion for electric power production. Coal is the principle source of energy in Poland. A calculation based on the Pasquille equation (computer program ATMO) for point sources was applied to asses the fly ash dispersion from coal-fired power plants (CPP) in Poland. The activities of J38U and 210Po in fly ash samples were measured by alpha spectrometry. Maps of the annual increase of the activity concentration in the air and of the annual increase of activity falling on the ground were made. Exposition by inhalation, oral ingestion and external irradiation was taken into account. The assessed value of individual effective dose equivalent commitments, EDEC, for the critical group is 0.1 mSv, i.e. 4% of the individual dose equivalent from all sources of natural radiation. The collective effective dose equivalent commitments, CEDEC, received by all inhabitants of Poland as a consequence of annual coal combustion in Polish CPP is about 367 man-Sv/a (i.e. 47 inan-Sv per GW-year), 0.4% of the dose from natural radiation. Assessctnent of Radon activity in dwellings (work in progress) T. Niewiadomski, M. Nowina-Konopka, M. Budzanowski, and M. Waligórski. Exposure to radon (222Rn) and to its daughter products inside homes is now recognized to be one of the main sources of radiation doses to the general public and in some situations is perceived to be a significant health hazard. A large-scale national programme of measuring of indoor radon concentrations using CR-39 track detectors is currently under way, in collaboration with the Central Laboratory of Radia- tion Protection (CLOR) in Warsaw. 850 cups containing CR-39 detectors were distributed in the regions of Poznań, Słupsk and Krakow at the beginning of November 1991. Two six-month exposures are planned. Every detector was accompanied by a questionnaire developed in our Laboratory, providing information about types of dwellings and occupational patterns of their inhabitants. On the basis of this questionnaire and on the measured values of 222Rn concentra- tions, an assessement of the radiological impact of radon and its decay products to the household members will be evaluated. Inter-calibration exposures of radon cups were made at CLOR and population control groups selected. o Simulation of the response of an ultraminiature microdosimetric counter for fast neutrons P. OIko and K. Morstin. Institute of Physics and Nuclear Techniques, University of Mining and Metallurgy, Kraków. (paper presented by P. Olko at the 7th Symposium on Neutron Dosimetry, Berlin, 14-18 Oct. 1991) Low-pressure tissue equivalent proportional counters, TEPC's, found extensive application in radiobiology which requires information about the interaction between primary radiation events 378 at distances of the order of few nanometers. However, the conventional TEPC cannot simulate diameters much smaller than 1 fim because the avalanche region extends into a large fraction of the collecting volume. Only recently, a new ultramiiuature microdosimetric counter (UMC) has been developed to measure ionization distribution in nanometer targets [Kliauga, Radiat. Res. 124, 1990]. In this work ionization distributions induced in nanometer targets by neutrons and photons were calculated using the results of track structure simulation of charge particle tracks in water vapour (code MOCA-14). Next these tracks were used to build a four-parameter model which makes it possible to calculate ionization distribution in a spherical target of given diameter and for given ion species. Finally, the slowing-down spectra of neutron-induced charged particles were calculated with the NESLES program and combined with the model to obtain ionization distributions in 5, 10, 20 and 50 nm sites. Fig. 1. Comparison of calculated microdosimetric distri- bution in 5 nm targets (histogram) with re- sults of measurements with ultra- miniature TEPC (broken line). The bold line indicates the sug- gested improvement in calibra- tion of the counter. Lineal Energy, y / keV///m Distributions calculated for 5 nm and 10 run sites compare favourably with the measured spectra. There are some unexpected discrepancies at larger diameters. Our calculations en- able the verification of the calibration procedure used for interpreting the pulse-height spectra recorded by the UMC. What can we learn from simulations of particle tracks ? 12a. P. Olko and M.P.R. Waligórski (paper presented by M. Waligórski at the 23rd International Symposium on Radiation Protection Physics, Dresden-Gaussig, 8-12 April 1991) An essential element of Track Structure Theory is the radial distribution of tf-ray dose (RDD) around the path of an energetic charged particle transversing the irradiated medium. In mea- surements of the RDD in gases a single value of w, the average energy to produce an ion pair is used. Since w is known to significantly increase at electron energies below 1 keV, a Monte Carlo simulation (MOCA-14 code) of tracks of protons of of energy 0.5,1,10 and 20 MeV has been performed and applied to calculate the RDD, in the "energy deposited" or the "ionization" approaches. In the first approach, an average w-value over all radii r was calculated, in the sec- ond excitation and ionization events were scored with energy depositions appropriate for each 379 hype of event. Due to the variation of w with electron energy, each approach yields a different RDD distribution in tłw region close to the ion's path. In I ig. 1 we show analytical expressions for ,v(r) fitted to the MOCA-14 calculations. The analytical formula of Waligorski ct al.[Nucl. Tracks, 11, 309-319, 1986] was then modified by appropriate w(r) dependences. It was found that tiiis modification did not significantly affect the results of point-target calculations of th*. single-particle activation cross section for the FX-174 phage. Hovrever, for calculations of mi- crodosimetric distributions in sites of diameter below 20 nm, the "ionization" rather than the "energy deposited" approach should be considered. i—r~i mni—T—vr-rr _ MOCA-14 — fit > Fig. 1. Radial distribution of to- value calculated from simulated Profon enarjy fM«V| proton tracks. Lines represent —-ef analytical fits 1o histograms re- sulting from MOCA-14 simula- tions of tracks of protons of en- ergy 0,5,1,5,10 and 20 MeV. To read the value of w(r) subtract 0,10,20,30 and 40 eV from the value shown on the ordinaie. i-i -r" 1000 1000O RADIUS / nm y\% Are neutron data unsuitable for making predictions of radiation rises? M.P.R. Waligórski and P. Qlko (paper presented by M. Waligórski at the Workshop on Physical Modelling of Radiation Effects, Padua, 2-5 Sept. 1991) Experimental data on neoplastic transformations in C3H10T1/2 cells induced by X-rays, charged particles and monoenergetic neutron beams in the range 0.23-13.7 MeV were analyzed using Katz's cellular Track Structure Theory (TST) and the Biological Response Function (BRF) approach. Due to an apparent "degeneracy" of TST calculations, TST parameters cannot be reliably extracted from the neutron data set. The BRF derived from the same neutron data set is uncertain over the range of ^values exceeding 100 keV//«n. The shape of the BRF derived from measurements of chromosome aberrations induced in human lymphocytes by X- rays, neutrons and a-particles changes dramatically over the same range of y-values if oc-partide irradiations are excluded in the derivation of this BRF (see Fig. 1). We conclude that in order to make reliable TST or BRF model predictions of radiation risk, data covering a wide range of photon and charged particle irradiations rather than data from neutron irradiations alons, are necessary. 380 10 Fig. 1. Biological Response Function repre- senting dicentric aberrations in human lym- phocytes derived from all available data, in- cluding photon, neutron and a -particle irradi- ations (solid line) and after exclusion ofi3BPu and 7isCm a -particle data (dashed line).This illustrates the uncertainty of the IMF for y > 100 keV/m I00 To3O Lineal Energy, y / kcV//tpi STAFF PUBLICATIONS I. Articles: 1. M. Nowina - Konopka, Radiological Hazard from Coal-Fired Power Plants in Poland, submitted to Radiation Protection Dosimetry. 2. T. Niewiadomski, On LiF Thermohmunescence, chapter in a book Thermoluminescence Dosimetry, in press, Prentice Hall Inc. (USA). II. Contributions to Conferences: 1. P. Olko and M.P.R. Waligórski Microdosimetry versus Track Structure: What Can we Learn from Simulations of Charged Particle Tracks?, in print, Proc. 23rd International Symposium on Radiation Protection Physics, Gaussig, 8-12 April 1991 2. M.P.R. Waligórski and P. Olko, Are Neutron Data Unsuitable for Making Model Predic- tions of Radiation Risk?, in print, Proc. Workshop on Biophysical Modelling of Radiation Effects, Padua, Italy, 2-5 September JP91, to be published in the Proceedings of this meeting. 3. P. Olko and K. Morstin, Simulation of the Response of an Ultra-Miniature Micro dsoimetric Counter for Fast Neutrons, in print, Proc. 7th Symposium on Neutron Dosimetry, Berlin, 14-18 October 1991. III. Reports: 1. T. Niewiadomski and M. Waligórski, Zalecenia Międzynarodowej Komisji Ochrony Radiologicznej - Summary of Recommendations (ICRP Publication 60), Polish trans- lation. Raport No. 1546/D, INP Krakow, May 1991 381 2. M. Nowina - Konopka, Zagrożenie radiologiczne ludności i środowiska Polski na skutek spalania węgla kamiennego w elektrowniach, (Radiological Hazard from Cbai- Fircd Power Plants in Poland - in Polish), Report No. 1558/AP, INP Krakow 1991. 3. T. Niewiadomski, Dozymetria termoluminescencyjna w praktyce (TAexmoiumines- cence Dosimeiry Practice), Report No. 1550/D, INP Krakow, June 1991. SEMINARS ORGANIZED BY THE LABORATORY Weekly seminars on topical research subjects are held in the Laboratory on Wednes- days at 10:00 AM. In 1991 the Laboratory1 organized two national 1-day workshops: 3.1. National Workshop "The Concept of Risk in Radiation Protection", Krakow, April 24 1991, 3.2. Third Worshop on Microdosimetry in Radiation Protection (in collabora- tion with IME KF\ Tulich and AGH Krakow), April 25 1991 STAFF ACTIVITY: VISITS, CONFERENCES AND SEMINARS Laboratory staff participated and lectured at several meetings and conferences in Poland abroad. The list below is in chronological order. M, Waligórski participated and gave a paper (ref. 4) at the International Symposium on Radiation Protection Physics, Gaussig, Germany, 8-12 April 1991. T. Niewiadomski gave the keynote address at the National Workshop "The Concept of Risk in Radiation Protection, Krakow, 24 April 1991. M. Waligórski gave a lecture: "Radiation Risk and its Social Perception" at the National Workshop "The Concept of Risk in Radiation Protection", Krakow, 24 April 1991. P. Olko gave a lecture: "Radon in the Human Environment - Risk and Con- troversies" at the National Workshop "The Concept of Risk in Radiation Pro- tection", Krakow, 24 April 1991. P. Olko gave a lecture: "Simulation of Particle Tracks using the MOCA-14 Code" at the Third Workshop on Microdosimetric Concepts in Radiation Bio- physics, Krakow, 25 April 1991. M. Waligórski and P. OJiro served as Chairmen in the Panel Discussion at' the Third Workshop on Microdosimetric Concepts in Radiation Biophysics, Krakow, 25 April 1991. T. Nicwiadomski visited ENDOS GMbH, Berlin, Germany, 20-25 May. T. Niewiadomski and M. Waligórski took part in the National Seminar "New Recommendations of the ICRP - 1990", Warsaw, 7 June 1991. P. O/Jco visited IME KFA Julich 15 May - 15 August 1991. M. Waligórski and P. Olko participated and gave a paper (ref. 5) at the Work- shop on Biophysical Modelling of Radiation Effects, Padua, Italy, 2-5 Sept. 1991. 382 P. Olko and P. Bilski participated at the 7th Symposium on Neutron Dosimetry, Berlin, 14-18 Oct. 1991, where P. Olko gave a paper (ref. 6). P. Bilski visited KFA Julich 14-27 October 1991. M. Budzanowski visited KFK Karlsruhe, Germany, 'Ó November - 3 December 1991. T. Niewi&domski gave a lecture "Quantifiers of Radiation Risk" at the National Workshop "Formulation of ICRP Recommendations and Their Implementa- tion", Stara Miłosna, Poland, 17-18 December 1991. P. Olko gave a lecture "Introduction to Methods of Assessing Risk Applied in ICRP-60" at the National Workshop "Formulation of ICRP Recommendations and Their Implementation", Stara Miłosna, Poland, 17-18 December 1991. P. Bilski and M. Budzanowski participated in the National Workshop "Formu- lation of ICRP Recommendations and Their Implementation", Stara Miłosna, Poland, 17-18 December 1991. M. Waligórski visited Brookhaven National Laboratory (USA) 6-14 December 1991. M. W&Hgórski participated in the International Scientific Advisory Board to the 10th Solid State Dosimetry Conference, Washington, 16 December 1991. M. WaJigórski visited the University of Nebraska-Lincoln and gave a lecture: "Radiation Protection from a Track Physics Perspective", 17-22 December 1991. VISITORS TO THE LABORATORY Dr. Jan Lesz, ENDOS GMbH Berlin, May 3 1991. Mr. Wieshw Michalik, Institute of Radiation Dosimetry, Prague, Czecho- slovakia, 12-15 November 1991. 383 Laboratory for the Physics of Crystals IM: Laboratory for the Physics of Crystals RESEARCH AREAS AND OBJECTIVES: Tins research program consists of the preparation, structure determination, study of the physical pro- perties of condensed matter in particular at low temperatures and with special emphasis to magnetic properties. The main research themes are at present: - Magnetic, relaxation in high temperature superconductors. Structural and magnetic properties of interinetallir. rare-earth compounds and solid solutions. Magnetic properties of semiinagnetic-semiconductors. PRINCIPAL FACILITIES: - Faraday balance (Cahn RG) for determining magnetic susceptibility (4 - 400 K, fields upto 1 T). - X-ray universal powder diffractometer. - Arc melting furnace. STAFF; Dr Antoni Bajorek Dr Andrzej W.Pacyna Dr Henryk Rżany MSc Maria Balami a MSc Maria Doniec MSc Joanna Kosiorowska TECHNICAL ASSISTANCE: Ing. Waldemar Witek Andrzej Doliński VISITING SCIENTISTS: Dr Dubravko Rodić "Boris Kidrić" Institute of Nuclear Science, Vinca, Yugoslavia Dr Vojislav Spasojevic "Boris Kidrić" Institute of Nuclear Science, Vinca, Yugoslavia Dr M.Theo Rekveldt Iiiteruniversity Reactor Institute, Delft, The Netherlands COLLABORATION WITH OTHER INSTITUTIONS - Institute of Physics, Jagellonian University, Cracow - Institute of Nuclear Physics and Techniques, Cracow - Institute of Physics, Silesian University, Katowice -"Boris Kidrić" Institute of Nuclear Sciences, Vinca, Yugoslavia. - Knmerliiigli Onnes Laboratorium, Leiden, The Netherlands. - Netherlands Energy Research Foundation, ECN PeLten. 385 SCIENTIFIC PUBLICATIONS 1. V.Spasojevic, A.Bajorek, A.Szytula, W.Giriat, M.Mitic, "Magnetic .Susceptibility Calculation of Zni_xMnxS by the Nearest-Neighbour Isolated Cluster Model" Phys.stat,so!.(b).165 (J991),555. 2. Z.Tonikowicz, K.Latka, A.Szytula, A.Bajorek, M.Balanda, R.Kmieć , R.Kruk, A.Zygmunt "Superconductivity in the (Gdi_xPrx)Ba2Gu3-«O System" PhysicaC,174(1991),71. 3. Z.Tomkowicz, J.Żukrowski, J.Przewoźnik, A.Szytula, M.Balanda, A.Bajorek 7 "Mossbauer .Study of PrBay(Cu[i 902Feo.ooB)307_< in the Aspect of Superconductivity Absence" Physica C, 184 (1991), 244. CONFERENCES - POSTERS 1. S.Niziol, A.Bonibik, D.Fruchart, R.Zach, A.Pacyna "New Magnetic Properties of (Coi_xMnx)2P" Tenth International Conference on Solid Compounds of Transition Elements, Minister, May '21-25,1991. Poster P-218-Fr,Sa 2. G.Mavrodicv, S.Koucska, M.Fukarova-Jurukovska, M.Balanda, Z.Tomkowicz, A Szytula, "Effects of the Substitution on the Behaviour of YBaGuAO-_« Compounds at High Temperatures", III National Symposium on High-T,; Superconductivity, Wroclaw, October 21-22,1991. Poster P 23. 3. M.Balanda, A Bajorek, A.Szytula, Z.Tomkowir.z "Magnetic Relaxation in G 111 National Symposium on High-Tc Superconductivity, Wroclaw, October 21-22, 1991. Poster P 49. 4. P.Barta, S.Niziol, A.Bornbik, A.Proń, M.Zngórslta, A.Pacyna "Magnetic and Electrical Properties of Highly Doped Polythiophene" Conference Physics for Industry, Industry for Physics, Krakow, September 1991. Poster A 28a. 386 Superconductivity and Magnetic Relaxation 2ZA in GdPBCO M.Balanda, A.Bajorek, A.SzyUila* and Z.Tomkowicz* * Institute of Physics, Jagellonian University, 30-059 Kraków, ul. Reymonta A Unlike other rare earth elements, praseodirniuiri substituted to the yttrium suhlatlice in the Yi_xPr, Temperature K o o.ooos - E Gdi_xPrKBa2Cu3O7.d Fig.l.Magnetic susceptibility for zero field cooled £ -o.ow. samples of Gdi^Pr-Rn^CiidOT^jt. & Z H - 1380 Oe Splitting of curves - see text. 0_ uQ) VI IMHHH3 X = 0.05 3 w •+•+• X = 0.1 «•*•-»*-» x «= O.2 J -OOOltt ***** x = 0.25 -O.OO1S 387 decay was seen, connected with the increase of the relaxation time. It follows that magnetic relaxation at lowest Łeiuperiitiifes, where magnetic interactions in the rare earth sublattice become very strong, needs further study. H - 1380 Oo 20 00 ?.O 3O 40 Temperatur* K Toniperatur* K Fig.2.Temperalur.* dependences of the normalized Fig.3.Comparison of the activation energies Uo from relaxation rates for varied Pr contents. the TAFM model (dashed lines) with the average energy from the Hagen-Griessen model (solid lines). [I] P.W.Anderson, Phys.Rev.LeU.9,(1962),309. [2] C.W.Hagen, R.Griessen, Pliys.Rev.LeU.62,(l989),2857. Magnetic and Structural Properties of High Mn Concentrated LaCii5_xMnx and LCM J.Kosiorowska, H.Rżany, A..1.van Duyneveldf and R.B.HelmhoIdt** * Kamerlingh Onnes Laboratorium, 2300 RA Leiden, The Netherlands ++ Netherlands Energy Research Foundation, ECN Petten The investigations of magnetism of intermetallic compounds containing rare earth and transition metals atoms represent an important branch of magnetic research. Despite of tremendous amount of work in this field the lanthanum-copper-manganese system is still the one which needs an extensive study in order to determine the magnetic phase diagram. Non magnetic lanthanum and copper form four intermetallic compounds: LaCu, LaCu2l LaCus and LaCii6 [1]. LaCus was chosen for the present investigation as this compound shows the highest solubility of manganese up to 23 at. % [2], what gives the possibility for systematic study of magnetic properties as a function of manganese concentration. The two solid solutions with highest manganese concentration: LaCu3.7Mni.3 and LaCu4Mn were taken for investigation. X-ray and neutron diffraction studies showed that the sample are single phases and isostructural with LaCiir,, the hexagonal structure of the CaCiir, type - space group P6\mmm. The manganese atoms showed a preference to occupy positions in the a-b plane, midway the unit cell. The neutron diffraction 388 (int.u did not give a|iv evidence of long range magnetic ordering. The magnetic investigations were performed by three complementary methods: static suscepti- bility, fix. susceptibility nnd magnetization measurements, in the temperature range from 2K to HOOK. Low field static magnetic susceptibility measurements as well a.s zero field n.c. susceptibility data indi- cate that both samples exist in different magnetic phases: a high temperature paramagnetic phase and a low temperaturę spin glass one. The phase boundary based upon the occurence of a rounded cusp in the temperature variation of magnetic susceptibility (Fig.l) occurs til T/=3UK for La(Jua 7M111.3 and "Vj-MK for LaCu4Mn. 5.0 T r/1 50 100 150 2Ó0 250 300 Temperature [K] H [T] Fig.l.Static susceptibility vs T. Fig.2.Magneliza',ion vs if for LaCu.|Mn o -LaCu3.7Mii| a O-4.5K x - x - 50K The magnetization as a function of external magnetic field (0-5T) was measured for LaCt^Mn at several temperatures below and above T/. For the temperatures above T/ the magnetization behaves as for a normal paramagnet- field dependence is completely reversible. The irreversible effects start below Tj (Fig.2). The reniauence effects and irreversible |)henomena support the magnetic phase diagram as deduced from the susceptibility data. To determine the structural parameters and especially to find the arrangement of the copper and manganese atoms in a three component compound LaOugMnj of the ReTu type, neutron powder diffraction patterns have been measured with the high resolution diffractorneter at the HFR reactor in Petten. The experimental data have been analized using the profile refinement method of Rietveld [3]. It was found that LaCugMna has the tetragonal structure of the Ce(Mrio.s5Nio.45)n type - space group P4\mbm. The manganese atoms occupy two positions : (g) -- 91.5 % and (c) - 8.5 % . The neutron diffraction data show some weak extra reflections at the liquid helium temperature which are related to some magnetic ordering. [1] S.Cifarici and A.Palenzona, J.Less Common Met.53,( 1977), 199. [2] O-I.Boclak and E.J.Gladyshevsky, The ternary systems containing rare earth metals, Lvov (1985) - (in Russian). [3] H.M. Rietveld, J.Appl.Cryst.,2,(19G9),65. 389 1.(W Magnetic Susceptibility of Certain ReT2Sii2 Phases E. A. Ciorlich*, A. W. Pacyna * Institute of Physics, Jagellouian University, 30-059 Kraków, ul. Reymonta 4 The magnetic, susceptibility measurements reported hereabout are a part of a wide program con- cerned with investigations of a less- known subclass of rare-earth ternary compounds ReTjXj (where T is a d-l.ransition element) with X=Sn. The rare-earth elements chosen for the present study are those with nearly empty 4f-slmll (Ce), about half-filled 4f-shell (Stn) and almost full 4f-shell (Yb) and therefore one might expect them to show an attitude toward unstable valency or similar anomalous behaviour. Compounds with lanthanum and erbium were thought, of as the reference materials. Extensive research work carried out recently for these phases with a number of experimental, methods (X-ray diffraction, electrical resisitivity, heat capacity and ll!lijii MSssbauer spectroscopy) has proved an ocr.urence of in- teresting electronic properties at low temperatures [1,2]. Furthermore the value of the present magnetic investigations is increased by that they were carried out on parts cut off the physically same samples as used in all complementary measurements roffered to above. The table summarizes results of the magnetic susceptibility measurements which were performed in the temperature range from 5K to 275K. Compound Aotcin'/g] /'<•//I/«w] e„[K] He,,[Oe] CeNi2Sii2 1.63*10-° 2.34 -4.2 2320 CeAg2Sn2 2.86* 10-6 1.74 0.9 450 CeAii2Sri2 1.3*10-7 0.89 -0.4 2780 SmCuaSnj 2.46*10-6 0.72 -12.5 2550 SmNi2Sii2 2.30*10-" 0.75 -12.6 2780 ErCusSng -9.13*10"6 9.58 -7.2 C90 ErNi2Sii2 1.79*10-" 9.45 -4,1 450 In the case of CeNi2Sii2 present results (cf.Fig.l) have supplied a strong support in favour of the formation of the singlet ground state of a Kondo lattice nature in this system at temperature below 30K. 100 Temperoture [K] Fig.l. Magnetic susceptibility x(T) and inverse susceptibility x~'(T) for CeNioSi^. The susceptibility data cannot neither confirm CeAgxSnj nor exclude a superconducting nature as sus- pected on bases of resistivity measurements. Nevertheless, the strong reduction of effective magnetic moment of cerium with respect, to Ce+3 value is an interesting fact, in itself. The Móssbauer and re- sistivity experiments have revealed pronounced anomalies in electronic and lattice dynamical properties of samarium compounds at temperatures above 15K [3]. The present results exclude the magnetic cha- racter of the earlier observed features, while they confirm a magnetic ordering in SmCiiaSna at 8K. The transitions indicated by the maxima in the temperature dependence of the electrical resistivity remain, 390 however, beyond the accessible temperature range for the magnetic measurements. In general all samples investigated exhibit, the regular Curie-Weiss behaviour at temperatures above roughly IfiK. [1] E.A.Gorlich in J.Stanek arid A.T.Pcdziwiatr (cds.), Proc.XXVl Zakopane. School on Physics, Za- kopane, Poland, April 1091, World Scientific, Singaporc,1991,p.80 [2] E.A.Gorlieh, II.Kmieć, K.Łątka, A.W.I'acyna and A.GIeissner lo be published. [3] E.A.Gorlirh, Klatka and .l.Moser, Hyp.lnt. 50,(108J)),723. Magnetic Susceptibility and Magnetic Structure of ReNiGe Compounds A.Szytulw*, A.Oleś", A.Bornbik", W.S'ikora" and A.W. Pacyna * Institute of Physics, Jagellonian University, 30-05!) Kraków, ul. Reymonta 4 ** Institute of Nuclear Physics and Techniques, Academy of Mining .and Metallurgy, 30-059 Krakow, ul. Reymonta 19 A number of equiatomic ternary rare earth interinetallic compounds with a general formula ReTX (Re-rare earth element, T - d-transition element and X-In,Si|Sn,Ca,Ge) are known to exist [1-3]. They crystallize in several different types of structure [3-5], The compounds ReNiGe have an orthorombic crys- tal structure [6]. Magnetometrie measurements showed that above compounds (where Re = Dy,Br,Tb) were antiferrornagnets and their Neel temperatures were 9, C, 7K, respectively [6]. The mentioned compounds and HoNiGe2 were synthetized. In order to determine their magnetic structure, X-ray, neutron diffraction as well as magnetic susceptibility measurements were undertaken. The magnetic susceptibility measurements were carried out in an external magnetic Held of 360 Oe from temperatures below LHe up to 273K. The temperature dependences of magnetic susceptibility indicated luitifcrrovnagn'-tic nature of the all samples. But the compound TbNiGc stands out among all measured samples. As shown in the Fig.I two maxima, the first at 6.5K and the second at 19K appear. Futher- inore only for TbNiGe the paramagnetic Curie temperature Qp is positive. These facts may be taken as coexisting of different magnetic interactions. The initial results of structure determination by neutron diffraction confirm the above and suggest the following interpretation. TbNiGe is ordered antiferromag- netically below Tjv = 19K. In the temperature range 14K-T;v the sine modulated structure is observed. Below MK two magnetic structures: sine modulated and square modulated are coexisting. „too TbNiGe ao \c DAT 10"* K-om'/g w vi OT ŁO CO VI 0.0 (i SO 100 150 KOO Fig.I. Magnetic susceptibility of TbNiGe. TEMPERATURE [K] 391 In Łlit! table mentioned lielow the numerical results of magnetic susceptibility measurements are collected. 3 Compound 1 \'o[cm /g] lhff[hu] T [K] ePlK] W DyNitie -1.14*10-° 10.42 -8.2 5 6 ErNiGe 5.4* 10" 9.19 -1.4 3(?) HoNiGe2 5.1*10-° 11.20 -2.6 5 TiiNiGe 1 l.3'2*10-r' 8.97 +4.1 19 [1] E.Hoveslreydt, N.Cngel, K.KIepp, B.Chabot and E.Parthe, J.Less-Common.Met. 85,(1982),247. [2] D.Mazzone, R.Rossi, R.Mara/za and R.Ferro, ,1.Less-Common.Met. 80,(1981),47. [3] D.Rossi, R.Marazza and R.Forro, J.Less-Common.Met. 107,(1985),99. [4] W.Bażela, J.Less-Commou.Met. 133,(1987),193. [5] E.I'arthe and B.Ciiahol in: Handbook on the Physics and Chemistry of Rare Earths,vQ\.7,etls.K.A.GBc\\xmAm and L.Eyring (North-Holland, Amsterdam 1984) chap.48 p.113 [6] P.A-Kotsanidis, J.K.Yakinthos and E.Gamari-Seale, J.Less-Common.Met.l57,(1990),295. Static Magnetic Susceptibility of New Semiconducting Polymers Doped with. Paramagnetic Ions Complex P.Barta*. S.Niziol*, A.Bombik*, A.Proń", M.Zagórskrf *, A.W.Pacyna * Institute of Physics and Nuclear Techniques, Academy of Mining and Metallurgy, 30-059 Krakow, al. Mickiewicza 30 ** Department of Chemistry, Technical University of Warsaw, 00-GG4 Warszawa, ul. Noakowskiego 3 In the doping process of polythiophene chain charge carriers, polarons and bipolarons, are intro- duced into the polymer conjugated chains [1J, Due to the doping reciprocal settlement of polymer chains are changed, as well. For above reasons mechanism of electronic transport fundamentally depend on the dopant concentration and on dimension of dopant molecule. If polymer matrix is doped with paramagnetic ions complex, magnetic measurements may be usefull as a source of additional information about electrical transport processes. Influence of localized magnetic moments of dopant ion on delocalization of charged defects or pairs of them (polarons, bipo- larons) as the effect of theirs interactions is expected. Investigated polymers: poly(3-heksylo)liophene (P3HT), poly(3-octylo)tiophene (P3OT) and poly(didecylo)bitiophene (PdDbT) were doped with ferrichloride FeCl3. In the doping process negative tetragonal FeCI^ complex is formed as the counter ions for the positively charged polymer chains. The magnetic susceptibility us T has been measured for samples +r (P3HT,P3OT,PdDbT) (FeCl;))1 - where x means dopant concentration per mer of polymer matrix. For P3HT, P3OT, PdDbT matrices x were equal to 0.02, 0.10, 0.42; 0.04, 0.11, 0.41 and 0.03, 0.30 relatively. The temperature dependences of inverse susceptibility indicate localized spins (Curie-Weiss law, Fig.l). •> *••• 392 Fig.l. Inverse susceptibility ofP3Ht ..0.02 •? *• ~ 3 Z2 -1 0>2 50 100 150 200 250 TIK) Obtained results will be helpfull for understanding of nature of the interaction between polymer conjugated chain and dopant molecule. An additional ESR and Mbssbauer spectroscopy experiments are curried out. {11 tUłarbeke.D.Baeriswyl, H.Kiess, W.Kobel, Physica Scripta T13,(198G),302. Computer Control for Magnetic Susceptibility Measurements on C?,hn Electrobalance W.Witek The full computer control and data acquisition system for magnetic susceptibility measurements was created to make the measurements faster and more convenient. System is built in IEC-625 standard and contains the following devices:two controlled voltage sources (CVS1,GVS2) with resolution of I'.: bits (4096 voltage values), microvolt signal analog multiplexer (MSAM), 4 1/2 digit programmable DC voltmeter (V4) and computer F'C/XT with IEC-625 interface working as IEC-625 controller.First voltage source (GVSt) sends calculated settings to temperature control subsystem, second (CVS2) controls the subsystem generating magnetic field. Output data records are sent to ASCII output file existing on hard disk in PC/XT. It is possible to view the output data on graphic diagram during the measurement. magnetic field temperature 1 Calm Electrbalance [CVS I CVS2 MSAM |\ I ComputerPC/XT | I IEC - 625 BUS I NEXT PAGE(S) I tatt BLANK 393 PATENTS: Patents approved: 1. Patent No 153820 (P-262541) "Dosimetric card bAdge" 2. Patent No (P-264112) "Method and device for filtration of liquids in the magnetic field" 3. Patent No 156035 (P-269110) "Recovery of rare earths from acid solution by means of the extraction and back-extraction method" 4. Patent No 156292 (P-270711) "The device for filtration of liquids in the magnetic field" Patents submitted for approval: 1. Invention P-288981 "Ion capture electrostatic device" 2. Invention P-289253 "Semiconductor detector for charged particles" 3. Utility model W-92181 "Device for magnetohydrodynamic water treatment in forced cir- culations" 4. Invention P-289338 "Method and device for the treatment of water solutions of liquids, especially cooling liquids, and for increasing the OCTANE and CETANE numbers of fuels" 5. Invention P-290302 "Device for filtration and for magnetohydrodynamic treatment of liq- uids, especially water" NEXT PAOg(S) I Jeft 395 INP AUTHOR INDEX: Adamcaak A., 40,41 Florek B., 217 Adaniski A. 217 Florkowski W 186,193 Bajorek A ....387 Fornal B 25,27,78,96,154 Balanda M., 387 Freindl L., 25,27,36,38 Bannś E., 227 Gabańska B., 282,288 Bartke J 225 Gadomski S 241 Bednarczyk P., 78,80,96,154 Gałuszka K., 217 Biaks P 251 Gdański T., 217 Biatkowski E., 57 Glebowa L., 143,148 Bilski P 377 Gladysz-Dziaduś E., 225 Bochnacki P 186 Godlewski J., 227,232 Bogacz J 283 Golec-Biernat K 185,193 Bożek A., 232 Görlich L., 227,232 Bożek E., ., 78 Górski A.Z., 347,349 Bożek P., 187,187,188,188 Grçbosz J 152,156,158 Broda R., 65,67,80,90,150 Gruszecki M., 37,37 Broniowski W., 189,190 Grzyborowski R., 277 Budzanowski A 3,3,4,5,36,38,51 Guła E., 42 Budzanowski M., , 377,378 Hajdas I., 287 Budziak A., 217 Hajduk L., 227 Burda J 282 Hajduk R 148 Cebulska-Wasilcwska A 365,357,361,363 Hajduk Z., 217,232 Cerkaski M., 191,191 Holyński R. : 236,237,239 Cetnar K 251 Horzela A 186,195 Chwastowski J., 224,251 Hrynkiewicz A., 106,108,110,112,114,116 Chyliński Z., 342,345,346 Huczkowski J., 366 Cy wieka-Jakiel T., 286,287,288 Igielski A., 282 Cyz A., 227 Jagielski S., 251 Czerski P., 183 Jakiel J., 38,54 Czermak A 247 Jakubowski A-, 334,336,338,340 Czubek J.A 275 Jakubowski T., 306 Czyż W., 192 Jakubowski Z., 234 Ćwiklewicz M 334,336,338,340 Janicki M., 98,152 Dąbrowska A., 236,239 Janik J.A., 177,177,178,178,179 Dąbrowski H., 25,27,28,30,32,33,51 Jałocha P., 217,241 Dąbrowski J 282 Janczur W., 227 Droïdowicz E 288 Jasiński A., 305,306,307 Drozdowi« K., 280,281 Jasińska M., 326,327,328 Drożdż S., 7,8,10,11,13,15,16,18,19,21,192 JurakA., 237,239 Drwiçga M., 135 Kajetanowicz M., 217,249 Dryzek E., 129 Kajfosz J., 145 Dryssek J -129 Kamiński P 183,192,194 Dutkiewicz E.M., 140 Kamiński R., 194 Dworak D., 285 Kantor W., 4,56 Dwurainy A., 224,234 Karcz W 36,38 Eskreys A., 224,225,226 Kapusta P., 217 Figiel J., 226 Kapuścik E., 186,195,195 Florck A.,' 217 Kasper E., 363 397 Klic»ewski S., 36,37,37 Misiak R., 315,319 Kmieć R 120,122 Mnich E., 277 Kolber S., ._ 279 Mosec»yński S., 241 Kołacskowski A., 316,319 Moszczyńska M 36Ö Kopta S 133 Muryn B., 217,234 Korcyl K 217 Natkaniec I., 178 Kosiorowslta J., 388 Niczyporuk B., 234 Kotsrba A., 234 Niewiadomski T., 377,378 Kowalski M„ 225 Nowak G 227,234 Kowalik W., 282 Obryk E 338,342,344 Kozak K 326,327,328 Okoïowicz J., 18,19,21 Krasnowolski S., 366 Olejuicrak Z., 304 Krasny W., 227 Olkiewicss K 225,226 Krawcsyk 3., 177 Olko P., 378,379,380 KrólasW., 76,96,154 Olssewski A., 239 Kruk R., 122 Olszowska J., 227 Krupiński W 217 Pacyna A.W 390,391,392 Krynicka E.( 282 Pakoński K., 217,232 Krzykwa B,, 363 Paleta A., 217 Kubka B., 325,326,327 Palka H., 217,232 Kulawik I 325 Patliński K.i 302 Kulawik J., 319,325 Pawlat T., 78 Kulczykowska K., 366 Pawlik B., 226 KutscheraM,, 190,196 Petelenz B 317 Kwiatkowska J., 124 Piotrkowski K 224 Kwiatek W.M., 136,138,143,148 Ploszajczak M 10,21,183,184,187,187, Kwieciński J., 184,185 188,188,192,194,197 Kwieciński S., 307 PolokG., 217 Lach M., 67,78,86,88,92,93,95 Potempa A., 9« Łasa J., 276,276,276 Rajchel B., 133,135,148 Lekki J., 131,133,138 Róg S., 217 Lemler M 227,334 Ryba E., 37T Lesiak T ; 217,234 Rybicki K., 217,227,232 Lcśniak L., 190,190,194 Rydsy M., 306 Leśniewski P., 122 Rżany H. 388 Lewandowski Z., 36 Sagnowski S., '. 307 Lipińska E., 13& Schwabe J 371 Łaaarska B., 366 Schwabenthan J., 328 Loskiewicz J., 283,284,285,286,287,288 Sieniawfki J. 147,148,150 Macharski P 326,327,328 Siwek A., 4,5 Madeja M., 36,37,37,38 Skwarnicki T 234 Maj A., 70,72,73,74,74,75,76,78,96,154 Skwiiczyńska 1 36,38 Makowska-Rsessutko M 55,56 Sobala A., 261,253 Malecki P., 226,251 Stokowski T., 3,18,23 Malecki A., 196,196 Stachura Z., 100,102,104,131 Maniawski F., 124,126 Starzecki W 88 Marczewska B., 143 Stefański P., 226 Marszałek M 106,108,110,112,116 Stodulski M., 217,244 Martyniak J., 227 Stopa P., 226 Massalska-Aiodi M., 179 Stopa Z., 217 Mayer J., 177, 178 Stiaceek A., 217 Maagaj Z 316 Stycïen J., ..78,80,82,84,86,88,93,96,148,152,154 Męczyński W 78,80,84,90,96,148,152,154 SulekZ 305 Michalowski J., 217 Swakoń J., 288 Mietclski J.W., 150,325,326,327,327,328 Sïalkowski Z 319 Mikocki S 227,238 Sïarska M 236,236,239 Mikulski J., 316,325 Sscsurek A., 3,3,8,10,11,13 398 Sifglowski Z., ..320,321,322,322,323,323,324,326 Wodniecki P., 106,108,110,112,114,116,118 S*mider J., 36,37,37,38,38,38 Wolski R., 36,37,38,38,39 Siymczyk S. 143,145 Wolter W 236,236,237,239 Tomanek B 307 Wosiek B., 237V239 Traci G., 286 Wośnicka U., 280,288 Trisupek A., 238,239 Wośniak K., 236,236,239 Turaîa M., 217,241,249 Zaehara M., .., 224 Turnau J., 227 Zając W 178 Urban J., 142,147 Zalewska A 217,241 Waligórski M., 378,379,380 Zalewski K 265 Wasiutyński T 175 Zapalski G., 334,336 Was B., 320 Zawiejski L., 224 WierbaM., 135 Zaiula J.M 283,284,289,290,291,292,293 Wieuewska A., 363 Zieliński P 176 WilwyńskaB 237,239 Ziębliński M., 154,160 Wilciyński H., 236,237,239 Ziółkowski M 42,44,46,48,50,61 Witek W., 393 Zuber K 82,90 Witek M., 217,232 ZubikS., 197 Wodniecka B 106,108,110,112,114,116 Zencïykowski P 198,199,199 CONTENTS: page j \ Department of Nuclear Reactions 1 X/1- (• Department of Nuclear Spectroscopy 63 ?/M- Department of Structural Research 169 9f* t Department of Theoretical Physics 181 '). •*>"! Department of High Energy Physics 211 ?.M o Department of Applied Nuclear Physics 273 ?>' I Department of Nuclear Radiospectroscopy 299 7.h I Department of Nuclear Physical Chemistry 313 9A^ Department of Reactor Technology 333 9 V| Department of Radiobiology 353 ?. H f Department of Acceleration Technique 371 2 'iG Health Physics Laboratory „. 375 2 ^ Laboratory for the Physics of Crystals 385 I1) i Patents 395 nl INP Author Index ; 397 C • ? s-o