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INIS-raf—9064 ISSN 0 158 2887
AUSTRALIAN INSTITUTE OF NUCLEAR SCIENCE AND ENGINEERING
10th AINSE NUCLEAR PHYSICS CONFERENCE
6th - 8th FEBRUARY 1984 RESEARCH SCHOOL OF PHYSICAL SCIENCES HUXLEY THEATRE
AUSTRALIAN NATIONAL UNIVERSITY CANBERRA
CONFERENCE HANDBOOK
(Programme, Abstracts and General Information) AUSTRALIAN INSTITUTE OF NUCLEAR SCIENCE AND ENGINEERING
1OTH AINSE NUCLEAIt PHYSICS CONFERENCE 1984
AUSTRALIAN NATIONAL UNIVERSITY
HUXLEY THEATRE
Monday 6th February, 1984 Sessions commence 10.15 a.m. - conclude 6.00 p.m. Conference Dinner - Pre-Dinner (Huxley Foyer) 5.30-6.00 p.m. - Buffet - Burgmann College Common Room 6.15 p.m.
Tuesday 7th February, 1984 Sessions commence 9.00 a.m. - conclude 5.00 p.m. Public Lecture - Huxley Theatre 8.00 p.m.
Wednesday 8th February, 1984 Sessions commence 9.00 a.m. - conclude 4.10 p.a.
Conference President
Professor Sir Ernest Titterton Australian National University
Conference Committee
Prof. Sir Ernest Titterton Australian National University Dr. J.W. Boldeman Australian Atomic Energy Commission
• '*• Assoc. Prof. L.S. Peak University of Sydney Prof. B.M. Spicer University of Melbourne Dr. L.J. Tassie Australian National University Mr. E.A. Palmer AINSE ft Conference Secretary Mrs. Joan Watson AINSE CONTENTS
PAGE I
PROGRAMME SUMMARY
PROGRAMME u--
ABSTRACTS 11
GENERAL INFORMATION 91
LIST OF PARTICIPANTS 95 ,
a-1-;
•r-l**~ rt i.
SUMMARY
Monday 6th February, 1984 - Australian National University OPENING REMARKS Prof. Sir Ernest Titterton (ANU) 10.15 • 10.20 Conference President SESSION I (Huxley Theatre) Chairman; Prof. Sir Ernest Titterton (ANU) 10.20 • 12.20 12.20 • 1.20 Lunch SESSION II Chairman: Prof. B.M. Spicer (Uni. of Melbourne) 1.20 - 3.00 3.00 - 3.20 Afternoon Tea SESSION III Chairman: Dr. T.R. Ophel (ANU) 3.20 - 5.00 SESSION IV POSTER SESSION A. Huxley Theatre Foyer & 5.00 - 6.00 Seminar Room CONFERENCE DINNER 6.15 Burgmann College Common Room Tuesday 7th February, 1984 SESSION V Chairman: Dr. I.R. Afnan (Flinders Uni. of S.A.) 9.00 -- 10.20 10.20 -- 10.40 Morning Tea S2SSI0N VI Chairman: Prof. S. Hinds (ANU) 10.40 -- 12.20 12.20 -- 1.20 Lunch SESSION VII POSTER SESSION B. Huxley Theatre Foyer & 1.20 - 2.00 Seminar Room SESSION VIII Chairman: Prof. H.H. Bolotin (Uni. of Melbourne) 2,00 - 3.00 3.00 -• 3.20 Afternoon Tea SESSION IX Chairman: Dr. J.K. Parry (AAEC) 3.20 - 5.00 PUBLIC LECTURE Huxley Theatre 8.00 "The Discovery of Artificial Radioactivity" - E.W. Titterton (ANU). Wednesday 8th February, 1984 SESSION X Chairman: Prof. B.H.J. McKellar (Uni. of Melbourne) 9.00 -- 10.00 10.00 •- 10.20 Morning Tea SESSION XI Chairman: Prof. C.A. Hurst (Uni. of Adelaide) 10.20 -- 12.20 12.20 - 1.00 Lunch SESSION XII Chairman: Dr. L. Tassie (ANU) 1.00 -• 2.40 2.40 -- 3.00 Afternoon Tea SESSION XIII Chairman: Prof. Sir Ernest Titterton (ANU) 3.00 - 4.00 CLOSING DISCUSSIONS Prof. Sir Ernest Titterton 4.00 - 4.10 Conference President •J
2.
CONFERENCE SESSIONS
MONDAY 6TH FEBRUARY, 1984 - Australian National University
TIME PAPER NO.
10.15 - 10.20 Opening Remarks - Prof. Sir Ernest Titterton (ANU) Conference President.
SESSION I (Huxley Theatre) Chairman: Prof. Sir Ernest Titterton (ANU)
10.20 - 11.00 1R Future Directions in Intermediate Energy Nuclear Review Physics. B.M. Spicer (Uni. of Melbourne).
11.00 - 11.20 2 A Shell-Model Description of Narrow, Highly- Excited States in 9Be. C.L. Woods, F.C. Barker (ANU). 205 11.20 - 11.40 3 Yrast States and Isomers in At. R.F. Davies (NPLUK), A.R. Poletti (Uni. of Auckland), G.D. Dracoulis, A.P. Byrne (ANU), C. Fahlander, (Tanden Lab. Sweden). 42 11.40 - 12.00 4 Alpha Particle Induced Reactions on Ca and the Mass 45 Bottleneck. L.W. Mitchell, M.E. Sevior, C.I.W. Tingwell, D.G. Sargood (Uni. of Melbourne). 4
12.00 - 12.20 5 Neutron Evaporation Following Heavy Ion Reactions for Systems with 150 < A < 190. A. Chatterjee, R.J. Charity, D.J. Hinde, G.S. Foote, J.R. Leigh, J.O. Newton, S. Ogaza (ANU)
12.20 - 1.20 LUNCH
SESSION II Chairman; Prof. B.M. Spicer (Uni. of Melbourne).
1.20 - 2.00 6R Pions and Muons - Beyond Exotic Atoms. Review E.W. Vogt (TRIUMF, Canada) 2.00 - 2.20 7 Comparison of Various Observations of M* (0.429) C.A. Ramm (Uni. of Melbourne). v™
2.20 - 2.40 8 Measurement of the g-Factors of High-Spin States in l58Er. C.G. Ryan, S.H. Sie (CSIRO), H.H. Bolotin (Uni. of Melbourne).
2.40 - 3.00 9 Coupled Channels Description of Resonant Structures in the 160 + 20Ne System. Y. Kondo, B.A. Robson, R. Smith (ANU)
3.00 - 3.20 AFTERNOON TEA 3.
MONDAY 6TH FEBRUARY, 1984 - Australian National University
TIME PAPER NO.
SESSION III Chairman: Dr. T.R. Ophel (ANU) •
3.20 - 4.00 10R Heavy-Ion Physics - The Future. Review J.O. Newton (ANU)
11 Measurement of Subthreshold Fission Cross *.00 - 4.20 Section in 23OTh(n,f). R.L. Walsh, J.W. Boldeman, (AAEC). I 12 Masses and Level Schemes of Very Neutron-Rich 4.20 - 4.40 Nuclei with A ^ 30. L.K. Fifield, P.V. Drumm, M.A.C. Hotchkis, T.R. Ophel, D.C. Weisser, C.L. Woods (ANU).
4.40 - 5.00 13 RHO Decay in the Cloudy Bag Model. L.R. Dodd. (Uni. of Adelaide)
SESSION IV POSTER SESSION A. - Huxley Theatre Foyer & Seminar Room.
5.00 - 6.00 14 Measurements of Angular Distributions for the 6Li(n.t)*He Reaction in the MeV Region. CM. Bartle (DSIRNZ)
15 Elastic Scattering of y-Rays at Small Scattering Angles. G. Hicks, R.B. Taylor, P. Teansomprasong, I.B. Whittingham (James Cook Uni. Nth.Qld).
• 16 Assessment of Underground Gamma Ray Fluxes at a Depth of 1230 Metres. A.M. Bakich, M. Omori. L.S. Peak, N.T.Wearne (Uni. of Sydney).
17 Relativistic Corrections to the Theory of Coulomb Excitation. M.P. Fewell (ANU).
18 Alignment of Neutrons and Protons in Rotating 190,192,194Hg Nuclei. A.P. Byrne, G.D. Dracoulis, S. Ogaza (ANU), H. HHbei (Uni. of Bonn).
!•' 19 Picosecond Beam Pulsing System using a Superconducting Resonator on the 14UD. D.C. Weisser (ANU).
20 The Interaction of 7Li with 160 at 50 MeV. P.V. Drmnm, L.K. Fifield, M.A.C. Hotchkis, T.R.Ophel, D.C. Weisser, C.L. Woods (ANU).
21 Chiral Symmetry and the U(l) Problem. G.A. Christos (ANU).
22 Resonant Structures in the Ne( 0, C) Mg Reaction. Y. Rondo, B.A. Robson, R. Smith (ANU). J
4.
MONDAY 6TH FEBRUARY, 1984 - Australian National University
TIME PAPER NO.
SESSION IV (cont'd) POSTER SESSION A. 59, 5.00 - 6.00 23 The 58Ni(p,Y> Cu Cross Section and its Importance for Nucleosynthesis and Statistical Model Studies. C.I.W. Tingwell, L.W. Mitchell, M.E. Sevior, D.G. Sargood (Uni. of Melbourne).
" " 24 Inelastic Scattering of Intermediate Energy Protons from Tungsten. B. Lay (Uni. of Melbourne).
25 Parity Admixtures in the Nucleon Wavefunction. B.H.J. McKellar (Uni. of Melbourne).
26 QCD and the Spectroscopy of Quarkonia. R.M. Gorman, B.H.J. McKellar (Uni. of Melbourne)
An Analytic Distorted Wave Approximation for Intermediate Energy Pion and Proton Inelastic Scattering. F. DiMarzio, K. Aroos (Uni.of Melbourne). + 42 ; 28 The Mean-Life of the Second 0 State in Ca, j P.M. Lewis, A.R. Poletti, M. Savage. (Uni. of Auckland} \ 29 Photoneutron Cross Section for C, N, and 0. M. Facci, M.N. Thompson (Uni. of Melbourne).
30 Irreducible Representations of Superalgebras with Central Charges. R. Farmer (Uni. of Tasmania)
31 Introduction to the Quantum Field Theory of Bag Models. L.R. Dodd, C.A. Hurst, M.A. Lohe. (Uni. of Adelaide).
32 Soliton Bags in Quantum Field Theory. \ A.G. Williams, R.T. Cahill (Flinders Uni. of S.A.) )
Vacuum Structure in QCD. C. Roberts, R.T. Cahill, (Flinders Uni. of S.A.).
CONFERENCE DINNER 6.15 Burgmann College Common Room. 5.
TUESDAY 7TH FEBRUARY, 1984 - Australian National University
TIME PAPER NO.
SESSION V Chairman; Dr. I.R. Afnan (Flinders Uni. of S.A.)
9.00 - 9.40 34R Weinberg-Salam and Beyond. Review C.J. Hamer (ANU).
9.40 - 10.00 35 Unitarity and K-Matrix Model Fitting. B.C. Pearce (Flinders Uni. of S.A.). 10.00 - 10.20 36 Lattice Gauge Theory. C.J. Hamer (ANU) I 10.20 - 10.40 MORNING TEA
SESSION VI Chairman; Prof. S. Hinds (ANU).
10.40 - 11.20 37R Pioneering with High Energy Heavy Ions. Review J. Rastnussen (Uni. of California).
11.20 - 11.40 38 Neutron Emission From Accelerating Fission Fragments. D.J. Hinde (ANU).
11.40 - 12.00 39 Gluon Propagator in Quantum Chromodynamics. H.A. Slim (Uni. of Western Australia).
12.00 - 12.20 40 Octupole-Vibrational States in the Even Mass Isotopes of Barium. M. Burnett, A.M. Baxter, S. Hinds, F. Pribac, R.H. Spear, W.J. Vermeer, (ANU)
12.20 - 1.20 LUNCH
SESSION VII POSTER SESSION B. - Huxley Theatre Foyer & Common Room.
1.20 - 2.00 41 Variation with Excitation Energy of Even-Odd Charge Effects in 252Cf Fission Neutron Emission. R.L. Walsh (AAEC).
42 Wigner Coefficients for Semi-Simple Lie Groups: A Pattern Calculus for 0(N) and U(N). M.D. Gould (Uni. of Western Australia).
43 Long Lifetimes and Moments Through the Bac.kbend in 168W. G.D. Dracoulis (ANU).
44 Coulomb Excitation of the Nucleus Li. W.J. Vermeer, R.H. Spear, M.T. Esat, M.P. Fewell, A.M. Baxter, S. Hinds, S.M. Burnett (AMU).
45 Pre-Equilibrium Charge States of Swift Chlorine Ions in Solids. H.J. Hay, L.F. Pender, P.B.Treacy. (ANU).
46 High Spin States in Fr Nuclei. A.P. Byrne, G.D. Dracoulis (ANU), H. HUbel,(Uni. of Bonn), R.F. Davie (Uni. of Auckland).
• **-. 6.
TUESDAY 7TH FEBRUARY, 1984 - Australian National University TIME PAPER NO. SESSION VII (cont'd) POSTER SESSION B.
1.20 - 2.00 47 Polarization Transfer to Inner-Vacancies of Ions Swiftly Traversing Polarized Ion Hosts. A.E. Stuchbery (ANU)
48 Studies of Very Neutron-Rich Light Nuclei Using a Gas Target. M.A.C. Hotchkis, P.V. Drumm, L.K. Fifield, T.R. Ophel, D.C. Weisser, C.L. Woods (ANU). 49 Parity-Dependence of the Nucleus-Nucleus Potential and l&0_+ 24Mg Elastic Scattering at 9 = 90°. Y. Kondo, B.A. Robson, R. Smith, J. Nurzynski, P.V. Drumm, T.R. Ophel, D.F. Hebbard (ANU).
50 Proton Induced Reactions on C% and their Relevance to Nucleosynthesis. R.O. Weber, L.W. Mitchell, M.E. Sevior, C.I.W. Tingwell, D.G. Sargood (Uni. of Melbourne).
51 Localized I Window from Partial Fusion Reactions Accompanied by Proton, ^uteron, and Triton Emission. H. Yamada (Uni. of Melbourne).
52 Spin Dependent Effects in Pion-Nucleus Scattering. L. Berge (Uni. of Melbourne). 121 53 Photoneutron Reaction Cross Sections of Sb, l23Sb and Nat. Sb. R.P. Rassool, D. Orr, M.N. Thompson (Uni. of Melbourne).
54 The Ca(y,n+p) Photonuclear Cross Section in the Giant Dipole Resonance Region. G.J. O'Keefe, Y.I. Assafiri, M.N. Thompson (Uni. of Melbourne).
55 Particle-Hole Description of the Nuclear Giant Dipole Resonance in Light-to-Medium Nuclei. Y.I. Assafiri, I. Morrison (Uni. of Melbourne).
56 The Pj- Channell and the Effects of Crossing Symmetry. R.J. McLeod (Flinders Uni. of S.A.).
57 Comparison of Neutron-Deuteron 3nd Proton-Deuteron Analysing Powers. R. Garrett, A. Chisholm (Uni. of Auckland).
I !.• 58 Location f 3p-3h Strength in N via the Reaction (.p) at 118 MeV. P.R. Andrews. B.M. Spicer G.G. Shute, V.C. Officer, S.F. Collins, J.M.R. Wastell, (Uni. of Melbourne). H. Nann, D.W. Devins, W.P.Jones, C. Olmer, Qingli Li (Indiana Uni.)
59 The 4OCa(p,pd)38K and 4OCa(p,2p)39K Reactions at 150 MeV. J.M.R. Wastell, B.M. Spicer, G.G. Shute, (Uni. of Melbourne), P.X. Schwandt, D.W. Devins, B.S. Flanders, D.L. Friesel, W.P. Jones, Chen Shen, L.C. Welch (Indiana Uni.). A.A. Cowley, S.J, Mills, J.J. Lawrie (National Accel. Centre, Sth.Africa).
•"- " "V '.~^T.^~J'W H 7.
TUESDAY 7TH FEBRUARY, 1984 - Australian National University
TIME PAPER NO.
SESSION VIII Chairman: Prof. H.H. Bolotin (Uni. of Melbourne)
2.00 - 2.40 60R Photonuclear Reactions in Light Nuclei. Review M.N. Thompson, (Uni. of Melbourne)
2.40 - 3.00 61 Direct Reaction Analysis of Heavy Ion Collision from the Quasi-Elastic to the Deep-Inelastic Regime. H. Lenski, S. Landowne, H.H. Wolter (Uni. of Mtlnchen), T. Tamura, T. Udagawa (Uni. of Texas).
3.00 - 3.20 AFTERNOON TEA "I.-' SESSION IX Chairman; Dr.J.K. Parry (AAEC) 3.20 - 4.00 62R A Nuclear Physics Programme with the Proposed Review 8MV Tandem Accelerator at Lucas Heights. •y J.W. Boldeman (AAEC). 4..00 - 4.20 63 The 0(Y.n) Cross Section. P. Zubanov, M.N. Thompson (Uni. of Melbourne), B.L,Bermann, (Uni. of California), R.E. Pywell (Uni. of Saskatchewan), J.W. Jury (Trent Uni.), K.G. McNeill (Toronto Uni.).
•.20 - 4.40 64 Medium Corrections in Inelastic Proton Scattering at Intermediate Energies. W. Bauhoff (Uni. of Melbourne).
4.40 - 5.00 65 Cosmological Constraints on Heavy Neutrino Lifetimes. H. Granek, B.H.J. McKellar, (Uni. of Melbourne).
PUBLIC LECTURE Huxley Theatre "The Discovery of Artificial Radioactivity" - 8.00 E.W. Titterton (ANU)
IV J
8.
WEDNESDAY 8TH FEBRUARY, 1984 - Australian National University
TIME PAPER NO.
SESSION X Chairman; Prof. B.H.J. McKellar (Uni. of Melbourne)
9.00 -- 9.40 66R The Future of Applied Nuclear Physics. Review G.J.F. Legge (Uni. of Melbourne).
9.40 -- 10.00 67 Quadrupole Moments of the 12 Isomers in Mercury 188 and Mercury 190. G.D. Dracoulis (ANU).
10.00 -• 10,.20 MORNING TEA
SESSION XI Chairman; Prof. C.A. Hurst (Uni. of Adelaide).
10.20 -• 11..00 68R The Future of Cosmic Ray Physics. Review C.B.A. McCusker (Uni. of Sydney).
11.00 -• 11.20 69 Composition of Cosmic Radiation for Energies of More than lOOTeV. M.M. Winn (Uni. of Sydney)
11.20 - 11.40 70 Variations of the Gyromagnetic Ratios of Corresponding States in 188,190,192Os; Measurements and Interpretations. A.E. Stuchbery, R. Bark (ANU), H.H. Bolotin, I. Morrison, L. Wood (Uni. of Melbourne;. q 11.40 - 12.00 71 El Decay of the First Excited State of Be. F.C. Barker (ANU).
12.00 - 12.20 72 The 48Ca(d\3He)47K Reaction of 80 MeV. S.M. Banks. B.M. Spicer, G.G. Shute, V.C.Officer (Uni. of Melbourne), G.J. Wagner (Max-Planck- Institut fur Kernphysik), W.E. Dollhopf (Wittenberg Uni.) Li Qingli, C.W. Glover, D.W. Devins, D.L. Friesel (Indiana Uni.).
12.20 - 1.00 LUNCH
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WEDNESDAY 8TH FEBRUARY, 1984 - Australian National University
TIME PAPER NO.
SESSION XII Chairman; Dr. L. Tassie (ANU)
1.00 - 1.20 73 The Partial Fusion Reaction and its Application to High-Spin Spectroscopy. H. Yamada (Uni. of Melbourne).
1.20 - 1.40 74 Fundamental Experiments with Neutrons. A.G. Klein,G.I. Opat, W.A. Hamilton. I (Uni. of Melbourne).
1.40 - 2.00 75 Theoretical Calculation of the Forward Cross Section for Deuteron Photodisintegration at Low Energies. W. Jaus (Uni. of Zurich). W.S. Woolcock (ANU).
2.00 - 2.20 76 Heavy Ion Induced Fission Reactions R.J. Charity (ANU).
2.20 - 2.40 77 Tensor Polarisation t.Q in Pion-Deuteron Elastic Scattering. J. Ulbricht, W. Grtiebler, V. Kflnig, P.A. Schmelzbach, K. Elsener, M.Merdzan, C. Schweizer (Eidg. Technische Hochschule, Zurich), A. Chisholtn (Uni.of Auckland).
2.40 - 3.00 AFTERNOON TEA
SESSION XIII Chairman: Prof. Sir Ernest Titterton (ANU)
3.00 - 3.20 78 The. K(p,a) Ar Cross Section and its Significance for Nucleosynthesis. M.E. Sevior, L.W. Mitchell, C.I.W. Tingwell D.G. Sargood (Uni. of Melbourne).
3.20 - 4.00 79R Detection of the W and Z Particles. Review L.S. Peak (Uni. of Sydney)
CLOSING DISCUSSIONS 4.00 - 4.10 Prof. Sir Ernest Titterton Conference President. J.
ABSTRACTS 11. FUTURE DIRECTIONS IN INTERMEDIATE ENERGY NUCLEAR PHYSICS
by
B.M. Splcer
School of physics University of Melbourne Parkville, Victoria, 3052
\ Abstract
Six areas are identified in which there will be, or could be, significant progress in the future. In the understanding of the nucleon- nucleon interaction, there is as yet no experimental measurement to indi- cate the degree to which the charge symmetry of nuclear forces is valid. This situation should be rectified following two experiments, to be done at TRIUMF and IUCF, on the scattering of polarized neutrons by protons at 500 and 200 MeV respectively.
The knowledge of simple excitation modes (giant resonances), has increased greatly in recent years; however the knowledge of isovector resonances remains minimal (excluding, of course, the giant dipole resonance). Recently, some evidence for the isovector monopole was indicated from pion charge exchange experiments, and searching with other charge exchange reactions will be considered.
Relativistic reaction theories for elastic nucleon-nucleus scattering : have appeared recently and indicate dramatic improvements in the fitting of measurements of spin-dependent quantities in reactions with incident energies greater than 200 MeV. The need to extend this formalism to other reactions is apparent.
>—^ The influence of the A-resonance (J * 3/2 , T = 3/2, Energy = 1232 MeV) on low energy nuclear properties - magnetic moments, B(Mi) values - will be discussed. Its influence is not as great as expected, and similar questions re other resonances will be raised. In similar vein, the importance of understanding dibaryon resonances (two nucleons and a pion) will be indicated, together with the present experimental situation. Finally, a first look at the possibility of observing quark effects in low 8.-/J energy nuclear physics will be discussed. %..v •••• .1* ••
••'•',
1R Session I Monday 10.20 - 11.00 a.m. 1R 12. A SHELL-MODEL DESCRIPTION OF NARROW, HIGHLY-EXCITED STATES IN 9Be by C.L. Woods Department of Nuclear Physics, Research School of Physical Sciences, and F.C. Barker if Department of Theoretical Physics, Research School of Physical Sciences, Australian National University, Canberra, ACT 2601.
Abstract
Four sharp peaks are observed in the inelastic electron scattering spectrum from 9Be in the excitation region from 14 to 18 MeV. These are the 14.393 MeV 3/2', T=3/2 and 16.975 MeV 1/2", T=3/2 levels and two positive parity levels at 16.671 and 17.493 MeV. Previous attempts to fit the form-factors were unsuccessful for the T=3/2 levels and assumed structures for the positive parity states which were inconsistent with their high excitation energies and narrow widths. In this paper we show that the Ml components of the form-factors of the T=3/2 states are sensitive to the p-shell interaction. Also the E2 convection current contributions are appreciably modified by the use of realistic single-particle wavefunctions incorporating the appropriate energies and parentage amplitudes for the various A= 8 core states. A better description of the 9Be positive parity states is obtained when the dominant configurations are assumed to have large parentage amplitudes with the 2 , T= 1 and second 2 , T= 0 states rather than the ground state in 8Be. In this model, the level observed at 16.671 MeV is identified as a 5/2+, T= 1/2 state, the odd nucleon being chiefly in the 2s,,, subshell, and the level at 17.493 MeV is identified as a 7/2+, T= 1/2 state, the odd nucleon being largely in the ld_.» subshell. r 5/ i.
Session I Monday 11.00 - 11.20 a.m. 13.
Yrast states and isomers in 20A5 t R.F. Davies* and A.R. Poletti i'A Department of Physics, The University of Auckland, Auckland, New Zealand and G.D. Dracoulis, A.P. Byrne and C. Fahlander** Department of Nuclear Physics, Research School of Physical Sciences, Australian National University, P.O. Box 4, Canberra ACT 26)), Australia.
The 29/2+ proton excitation has been identified in At and its mean life has been measured as 11.2(2) us. The mean life and decay of the 25/2 state were reinvestigafed. The ANU 14UD Pelletron accelerator provided beams of !3c ions (E <\< 85 MeV) which were used to initiate the 19^Au(l3C,5n)205At reaction. Standard y-ray spectroscopic techniques were used, including: y-y, y-neutron, y-x-ray coincidence measurements; excitation function, angular distribution and conversion coefficient measurements; and pulsed-beam-y and pulsed-beam electron timing. The level diagram summarises the results of the investigations. Relative Y-ray intensities as observed in the decay of the 11 vis isomer are indicated by the arrow widths. The 404 keV E3 transition, which depopulates the 2340 keV 29/2+ 205 state in At, has a strength 23W =11.2gs of 19(1) s.p.u. Similar 29/2+ 29/2*" states have been observed in 209,211Atj with energies increasing with neutron number. These also depopulate via li enhanced E3 transitions having strengths *»2) of 24(4) and 16.s.p.u. respectively). The 29/2+ state in 21iAt has been identified 2) as the 2 2 + |(hw2) 8M13/2; 9/2 > proton excitation and it is suggested that t he 29/2+ states in 205,20'At have the same proton configuration. A core polar- ization calculation reproduces the systematic trends of the excitation energy of the 29/2+ 21/2- and 13/2+ states with decreasing neutron number. This was not the case for the 23/2" Tr(hg/22 £7/2) state. This is attributed to substantial repulsion between the fj/2 proton and the f5/2 neutron holes, which arises due to the almost complete oveilap of their radial wave functions. Calculations of this effect are in progress. 1) Sjoreen et aL, Phys. Rev.C 1£ (1976) \023 2) Maier et al., Phys. Lett. 35B (1971) 401 *Now at Nuclear Physics Laboratory, Oxford, England, **Now at Tandem Laboratory, Box 533, S-751 21 Uppsala, Sweden. O Session I Monday 11.20 - 11.40 a.m. ^ 14.
ALPHA PARTICLE INDUCED REACTIONS ON ^Ca AND THE MASS 45 BOTTLENECK
by
L.W. Mitchell, M.E. Sevior, C.I.W. Tingwell, and D.G. Sargood
School of Physice Univeirsii.y of Melbourne Parkville, Victoria 3052, Australia Abstract i There is a bottleneck in the flow of nucleosynthesis in massive stars
at mass 45 caused by the abnormally low binding energies in this mass
region. The main flows through the bottlenock are currently believed to
follow the reaction chains t*2Ca(a,p)'l5Sc(p,Y)lf6Ti and 42Ca(a,Y)'*6Ti. The
cross section for ^ScfpfY)''^! is well known, but published experimental
data on "t2Ca(a,p)45Sc are sketchy, and on ^Cafa.YJ^Ti non-existent.
Experimental data on both these reactions are presented, comparisons with
global statistical-model calculations are made, and the significance of the
results for nucleosynthesis is discussed.
4 Session I Monday 11.40 - 12 noon 15.
IJEUTRON EVAPORATION FOLLOWING HEAVY ION REACTIONS FOR SYSTEMS WITH 150 < A < 190 by A. Chatterjee, R.J. Charity, D.J. Hinds, G.S. Foote, J.R. Leigh, J.O. Newton and S. Ogaza Department of Nuclear Physics, Research School of Physical Sciences, Australian National University, Canberra, ACT 2601.
Abstract
excitation functions for individual (xn) evaporation channels in the energy range 80-125 MeV for the fused systems 158Dy, 16SYb, 178W and 188pt are presented and compared with predictions based on statistical codes. A shift of the excitation functions for x = 3 to 8 is observed, resulting in evaporation of all excitation energies of about half a neutron less than predicted. Possible explanations are discussed.
m i
Session I Monday 12noon - 12.20 p.m. 16.
PIOKS AND MUONS - BEYOND EXOTIC ATOMS i/ by
Erich W. Vogt Director of TRIUMF Vancouver, British Columbia, Canada I fl Abstract With important new secondary bean lines at the meson factories, with taajor new detectors and spectrometers, and with urgent new questions in nuclear physics, the interest in plons and muons has recently gone far beyond the long-standing problem of exotic atoms. The current work in exotic atoms will be reviewed and some of the new interests described.
The recent advent of the standard raodel for quarks, leptons and their interactions has brought about a convergence of interests between particle physics and nuclear physics. Nuclear physics has adopted much of that part of the frontier which deals with precision or high intensity rather than with high energy. Important tests of the standard model include rare decays of pions and muons. With the aid of some extraordinary new detectors - especially time projection chambers - the rare decays are being pursued to extreme limits, the current state of the physics emerging from this pursuit will be reviewed along with a description of some of the experiments.
Pion beams and the resolution of pion spectrometers are now at the stage where studies with pions are producing important contributiors to nuclear structure. Beyond this, if one envisages the nucleus as a system of quarks, the pions are contributing to the understanding of hadronic aspects of the nucleus in which the usual nucleons may be excited to become delta particles. The role of pions in the nucleus has becorce central to the new questions confronting nuclear physics.
6R Session II Monday 1.20 - 2.00 p.m. 6R 17.
COMPARISON OF VARIOUS OBSERVATIONS OF M* (0.429)
by
C.A. Ramm
School of Physics University of Melbourne Parkville, Victoria 3052, Australia
Abstract
In the first neutrino interactions in bubble chambers an unexpected
imbalance of energy and momentum was observed in events where a neutral
(u,n) combination was produced. According to previous studies of pion
interactions with nucleons it was expected that the events would be pre-
dominantly energy deficient: in fact they were mainly momentum deficient.
This observation provoked the question of whether there could be a
process of the type:
v + jV+ M* +JV', followed by the decay,
+ M*yi r -»• vi~ + * .
The first neutrino experiments were inadequate to answer this question; there were indications compatible with such a process. From the study of K decays in the same bubble chamber there were strong indica- tions of M*^ (0.429).
Subsequently, the properties of M* have been studied in other neutrino experiments and in K decays. The observations from various experiments and their dependence on the properties of M* will be described.
References
[1] Further study of (V,TT) and (vty) invariant masses. C.A. Ramm, Phys.Rev.D 26, 27 (1982).
Session II Monday 2.00 - 2.20 p.m. 18.
MEASUREMENT OF THE g-FACTORS OF HIGH-SPIN STATES IN 158Er
by C.G. Ryan* and H.H. Bolotin
School of Physics, University of Melbourne, Parkvi.lle, Victoria 3052
S.H. Sie*
Department of Nuclear Physics, Research School of Physical Sciences, ANU, Canberra, ACT 2600 Abstract
Following the discovery of the back-bending effect by Johnson et al in 1970 (1] vigorous efforts were made to understand the underlying nuclear structure. g-Factor measurements, long recognized as a probe of the neutron-proton character of states [2], have not been extensively applied to back-bending nuclei populated in (Hl.xn) reactions, as the transient field, in conventional techniques [3], dies away long before the interesting yrast states are populated.
A technique was developed to utilize the transient hyperfine field to measure g-factors of states populated in (Hl.xn) reactions by introducing a time delay before precession in a magnetic field to exhaust the feeding time and hence optimize the population of the high-spin states of Interest. The delay was provided by recoil through vacuum between the target and ferromagnetic foils mounted on foil stretchers. An innovative design permits the ferromagnetic foil to be saturated in a magnetic field and cooled to liquid N£ temperature while simultaneously allowing unobstructed observation of de-excitation -y-rays over nearly 180° in the forward direction.
Dubbed the recoil-distance perturbed angular correlation (REDPAC) method, the technique was tested through an examination of 7m levels populated via Coulomb excitation, and proved effective in determining g- factors of discrete states up to the 21/2 level.
• Finally the technique was applied to a study of the backbending in the ': yrast band of i58Er populated in the reaction l3OTe(32S,4n)158Er. The 'I precession data were unfolded, enabling g-factors of discrete states through ? the back-bend to be directly determined. The data are consistent with RAL i.j model predictions [4], of neutron de-coupling above the 121" state. I 11] A. Johnson, H. Ryde and J. Sztarkier, Phys. Lett. 34B (1971) 605 I' [2] S.G. Nilsson and 0. Prior, Nat. Fys. Medd. Dan. Vid. Selsk. 32 (1961) f. No. 16 Sf f [3} A.E. Stuchbery, C.G. Ryan, H.H. Holotin, I. Morrison and S.H. Sie, N.P. A365 (1981) 317 [4] F.S. Stephens, P. Kleinheinz, R.K. Sheline and R.S. Simon, N.P. A222 (1974) 235
*Present address; Division of Mineral Physics, CSIRO, North Ryde, NSW 2113
Session II Monday 2.20 - 2.40 p.m. O 19.
COUPLED CHANNELS DESCRIPTION OF RESONANT STRUCTURES IN THE 16O + 20Ne SYSTEM
by
Y. Kondo, B.A. Robson and R. Smith
Department of Theoretical Physics Research School of Physical Sciences The Australian National University I Canberra, Australia
Abstract
As has recently been shown [1], the gross resonant structures observed in 160 + 20Ne elastic scattering and in the 20Ne(16O,12C)2IfMg (g.s.) 16 z0 reaction for 22.8 < Ecm<( 0 + Ne) < 38.6 MeV , can be described using extended optical mo3el and exact finite-range (EFR) DWBA approaches, respectively, which employ nucleus-nucleus potentials which include both a real parity-dependent term and an angular momentum (J) dependent absorptive term. These calculations, however, raised several problems: a) There was an observed difference between the degrees of trans- parency required to describe the elastic scattering and the •'••I.-: a-transfer reaction. b) The predicted elastic scattering angular distributions for 60° < 3c.m. 5 120° tended to be too large, and somewhat too oscillatory e for 4(5° i ec.m. < 80 In view of the suggestion that these problems may arise from the neglect of strong channel coupling, we have undertaken coupled channels calculations which employ such parity- and J-depend|nt terms in the 20 16 16 20 diagonal potential, for Ne( 0, O') Ne (g.s., 2lt4i) scattering.
It will be shown that a detailed coupled channels treatment offers a partial solution to the above problems and provides a good qualitative description of resonant phenomena for both elastic and inelastic scattering in the 160 + 20Ne system.
[1] Y. Kondo, B.A. Robson and R. Smith, Nuclear Physics A410 (1983) 289,
!**••
Session II Monday 2.40 - 3,00 p.m.
_-.:.--.^~:i*-r. fp 20. f. |, HEAVY-ION PHYSICS - THE FUTURE f: by ¥i J.O. Newton ?•• '&' Department of Nuclear Physics, Research School of Physical Sciences, s,; Australian National University, Canberra, ACT 2601.
!•- Abstract
Heavy ions with energies up to ^ 10 MeV/amu - have greatly enriched ;- our understanding of nuclear structure and of nuclear reactions. In the r structure field, heavy ions enable study of nuclei in extreme conditions |; of angular momentum, temperature and neutron to proton ratio. f t" Reactions between heavy nuclei range from Coulomb excitation, where f; the nuclei do not touch, to grazing reactions, harder collisions such as ^ deep inelastic scattering, through to fusion, where the two nuclei coalesce. Some of these reactions are poorly understood or not even properly identi- : fied and the boundaries between them are quite uncertain. The present situation in these areas will be reviewed and future directions discussed.
1OR Session III Monday 3.20 - 4.00 p.m. 10R 21.
MEASUREMENT OP SUBTHRESHOLD FISSION CROSS SECTION IN 230Th(n,f)
by
R.L. Walsh and J.W. Boldeman Australian Atomic Energy Commission I
A recent analysis (1) of data for the subthreshold fission of 230xh has confirmed the triple-humped shape of the fission potential barrier for nuclei in this mass region. The analysis used as input the fission cross section data from Blons et al. (2) and the fission fragment angular distribution data from Lucas Heights measurements.
There remain some small discrepancies between the fragment angular distribution data of various groups that need to be resolved. To finalise our study of the triple-humped fission barrier we have measured the fission cross section of 230-jh across the vibrational resonance at 715 keV. A comparison is presented of these data with those of Blons et al (2).
(1) Boldeman, J.W., Gogny, D., Musgrove, A.R. de L. and Walsh, R.L., •-JfK Phys. Rev. 22, (1980) 627. (2) Blons, J., Mazur, C, Paya, D. Ribrag, M. and Weigmann, H., Phys. Rev. Lett. 41 (1978) 1289.
'?.', • , 't «
11 Session III Monday 4.00 - 4.20 p.m. 11 22.
MASSES AND LEVEL SCHEMES OF VERY NEUTRON-RICH NUCLEI WITH A * 30 by L.K. Fifield, P.V. Drumm, M.A.C. Hotchkis, T.R. Ophel D.C. Weisser and C.L. Woods Department of Nuclear Physics, Research School of Physical Sciences, Australian National University, Canberra, ACT 2601.
Abstract
The 26Mg(18O,15O)29Mg and 26Mg(180,17F)27Na reactions have been studied in order to obtain accurate masses for the T = 5/2 nuclei 29Mg and 27Na. In addition, partial level schemes were obtained for both nuclei up to excit- ation energies of 6 MeV. Measurements involving the 2GMg(18O,16O)28Mg, 21tMg(18O,15>16O)27'26Mg and z£fMg(180,I7F)25Na reactions were also per- formed in order to assist in the determination of the structure of the strongly excited levels in 29Mg and 27Na. All the measurements were performed with a 110 MeV 180 beam from the ANU 14UD Pelletron accelerator. Reaction products were detected at the focal plane of the Enge split-pole spectrometer which was positioned at 8° to the beam direction.
12 Session III Monday 4.20 - 4.40 p.m. 12 23.
RHO DECAY IN THE CLOUDY BAG MODEL
by
L. R. Dodd
Department of Mathematical Physics University of Adelaide G.P.O. Box 498, Adelaide South Australia 5001
Abstract
The cloudy bag model (CBM) has been used with considerable success to describe the properties of the nucleon and other baryonic systems, but there have been few attempts to apply the model to the mesonic sector. The application to the mesons is more problematical, since the dual treatments of the pion, first as a quark-antiquark (qq) bag state and second as the single particle state cf the elementary pseudoscalar field introduced to restore chiral symmetry to the bag, must be reconciled. These difficulties will be brought out by considering the lowest order diagrams in the CBM for the decay p -> TT/TT . Unlike the perturbation calculations in the baryonic sector where qq processes may be consistently ignored, renormalization of the pion field by virtual bag states is necessary to obtain a consistent interpretation.
Calculations of the p-decay width in the CBM, using renormalized second order perturbation theory will be described, with emphasis on the I 'P technical difficulties of constructing suitable virtual bag states. ! I obtain a p width of r = 224 MeV without renormalization of P external pion propagators and a width of T = 143 MeV with renormaliza- tion using projected bag states. (The experimental width is TeKp =154+5 MeV .) P if
13 Session III Monday 4.40 - 5.00 p.m. 13 ;• 24.
[ MEASUREMENTS OF ANGULAR DISTRIBUTIONS FOR THE I 6Li(n,t)4He REACTION IN THE MeV REGION
K by A CM. Bartle
Isj Institute of Nuclear Sciences, DSIR, Private Bag, Lower Hutt, New Zealand.
Abstract
The use of scintillators to measure cross sections for neutron-induced reactions is well established but the technique cannot usually be applied i to measure angular distributions for reactions. The scjntillator bLiI(Eu) is unusual in that the light emission for the bLi(n,tpHe reaction is sensitive to the angles of emission for the particles and a computer method has been developed to calculate the distributions from the data.
An important feature of the technique is the analysis of the response curves for the product triton and a-particles. Earlier calculations assunied linear response curves.*' Most detailed calculations are based on a non-linear a-particle response curve.
The present work yields distributions which are in excellent agreement with earlier measurements by Weddell and Roberts'1' and Rosario-Garcia and Benenson.^'
The angular distributions show the smooth yet rapid variations in the 2-10 MeV range characteristic of compound nucleus formation.
The data set may be useful in theoretical studies of the mass 7 system and is of potential value in fusion reactor modelling.4'
1) CM. Bartle, Nucl. Instr. and Meth.} 176 (1980), 503. 2) O.B. Weddell and J.H. Roberts, Phys. Rev. 96.(1954), 117. 3) Rosario-Garcia and R.E. Benenson, Nucl. Phys. A275 (1977), 453.
4) G.L. Kulcinski, University of Wisconsin Fusion Engineering Program, 1982, private communication. !(
Session IV Monday 5.00 - 6.00 p.m. 14 25.
ELASTIC SCATTERING OF y-RAYS AT SMALL SCATTERING ANGLES by G.Hicks, R.B.Taylor, P.Teansomprasong and I.B.Whittingham Physics Department James Cook University of North Queensland, Townsville, Queensland, 4811 Abstract Differential cross sections for the elastic scattering $£344,411,444, i 52 723,779,868,964,1005,1086,1112,1275 and 1408 keV Y-raysfrom ' Eu-source have been measured for targets of Al,Cu,Ho,Sn,Ta,Pb and U, at scattering angles of 2,3,5 and 7 degrees. The results are compared with theoretical cross sections for Rayleigh plus nuclear Thomson scattering. The Rayleigh amplitudes were obtained from the Hartree-Fock form factor tabulations of Hubbell et alO). The Delbriick scattering contributions at 1275 and 1408 keV, calculated using the amplitudes of Papatzacos and Mork^'', was insignificant r at these scattering angles. The preliminary analysis indicates that the theoretical predictions are in agreement with the results at 3° but may be 5 to 10% less than the experimental results for 2° and 5°. The 7° data had not been analysed at the time of submission of the abstract.
I:
References (1) J.H.Hubbell et al., (1975) J.Phys.ChemRef.Data 4, 471-538. (2) P.Papatzacos, and K.Mork (1975) Phys.Rev.D 12, 206-18. :r^ !"
15 Session IV Monday 5.00 - 6.00 p.m. 15 I: 26.
ASSESSMENT OF UNDERGROUND GAMMA RAY FLUXES AT A DEPTH OF 1230 METRES.
by \i
A.M. Bakich, M. Omori, L.S. Peak and N. T. Wearne. 4
Falkiner Nuclear Department School of Physics,
University of Sydney. N.S.W. 2006.
Abstract
For two years, the Sydney neutrino group has been taking measurements underground to assess the background flux for a proposed solar neutrino detector. The measurements were taken at a depth of 1230m. in a mine at Broken Hill. This paper will discuss the various components of this background that will be a problem for a water cherenkov detection system; and will give an account of how this background was measurod. Particular emphasis will be laid upon the measurement of gamma rays with energies above 3 MeV. The results will be compared with data from other experiments around the world, and the implications considered.
Session IV Monday 5.00 - 6.00 p.m. 16 27.
RELATIVISTIC CORRECTIONS TO THE THEORY OF COULOMB EXCITATION by M.P. Fewell Department of Nuclear Physics, Research School of Physical Sciences, Australian National University, Canberra, ACT 2601.
Abstract
It has recently become plain that some Coulomb-excitation experiments
% •'• • :•% are now sufficiently precise for relativistic corrections to be significant. The standard semiclassical theory of Coulomb excitation for the case of back- scattering (e = 180°) is extended to include terms of order v2/c2 where v is the velocity of the projectile. It is found that excitation probabilities depend not only on the usual matrix elements M(E2) =
TABLE: Relativistic effects in the Coulomb excitation of the g-band of 19l*Pt by the backscattering of 550 MeV 136Xe
Level Relativistic correction (%)
(non-rel) M(E2;2)=0 M(E2;2)=R2M(E2) M(E2;2)=R2M(E2) M(2)=0 M(2)=0 M(2)=M(E2)A/Z
0.1208 -0.5 -0.5 -0.4 0.3989 -3.8 -3.9 -4.1 0.2496 +3.3 +3.3 +3.5 •a> ,:.. 0.0675 +9.5 +9.6 +10.2 0.0070 +14 +14 +15
#•••:
17 Session IV Monday 5.00 - 6.00 p.m. 17 28.
ALIGNMENT OF NEUTRONS AND PROTONS IN
ROTATING 190,192,mHg NUCLEI by A.P. Byrne, G.D. Dracoulis, H. Htlbel and S. Ogaza Department of Nuclear Physics, Research School of Physical Sciences, Australian National University, Canberra, ACT 2601.
Abstract Level schemes of ^90Hg, 192Hg and 19t*Hg were studied using the reactions 17O 21f Er( Mg,4n), i8tw(i3Cj5n-j and 186w(13Cj5n-)) respectively. Energies, intensities, angular distributions and Y-Y coincidences were measured with Compton-suppressed Ge-spectrometers, Level schemes for all three Hg isotopes are very similar. The even- spin positive parity (+0) bands exhibit two backbends. The first backbend is definitely attributed to the break-up and spin-alignment of an i-13/z neutron pair. The second backbend is possibly due to the alignment of nl1/2 protons.
18 Session IV Monday 5.00 - 6.00 p.m. 18 29.
PICOSECOND BEAM PULSING SYSTEM USING A SUPERCONDUCTING RESONATOR ON THE 14UD by D.C. Weisser Department of Nuclear Physics, Research School of Physical Sciences, Australian National University, Canberra, ACT 2601. I Abstract 4s A beam pulsing apparatus producing 47 psec FWHM bunches is in operation on the 14UD accelerator. The accelerator is preceded by a double gridded buncher operating at 37.5 MHz, which compresses 40% of the DC beam into the buncher 27 ns apart. After the accelerator, chopper 1 removes dark current adjacent to the desired bunch. Chopper 2 can be set to allow through pulses separated by 54 or 108 nsec. After energy analysis, a phase detector, compris- ing a 3 = 0.1 drift tube supported by a 37.5 MHz quarter wave stub, coordin- ates pre-acceleration and post-acceleration devices.
The time width for this apparatus is between 300 to 700 psec. These pulses are then compressed further by a super conducting split-loop resonator to 47 psec FWHM. The apparatus is now available as a standard experimental tool of the laboratory.
19 Session IV Monday 5.00 - 6.00 p.m. 19 30.
THE INTERACTION OF 7Li WITH 160 AT 50 MeV
by
P.V. Drumm, L.K. Fifield, M.A.C. Hotchkis, T.R. Ophel, D.C. Weisser and C.L. Woods
Department of Nuclear Physics, Research School of Physical Sciences, Australian National University, Canberra, ACT 2601.
Abstract
The scattering of 7Li on le0 has been measured at 50 MeV using the Enge spectrometer on the 14UD accelerator at ANU. Angular distributions have been obtained for the elastic scattering channel and for the reaction 16O(7Li,7Be)16N with the view of studying the mechanism of the charge exchange reaction rather than the nuclear structure of the final nucleus, 1SN. With this in mind, the states in 16N which are of particular interest are those which can be described by a simple shell model picture which considers 160 as a closed core and 16N as a proton hole coupled to a single neutron in the 16 2si/2 or d5/r2 subshells: the low-lying states in N at 0.0(2~), 0.120(0"), 0.297(3) and 0.397 MeV (1~) can be described in such a way by coupling a Pl/2 proton hole to a neutron in the ds/2 or 2sx/2 shells. The high-lying 4~ state at 6.17 MeV excitation in 16N is also of interest since it corres- ponds to an aligned ds/2 neutron and P3/2 proton hole, and has a pure con- figuration within the considered p and sd shells.
With such a simple view of the 16N shell model structure it is antici- pated that a reaction model analysis of the data should be clearly able to determine the reaction mechanism, either in terms of a direct exchange process or as a 2-step sequential transfer process.
20 Session IV Monday 5.00 - 6.00 p.m. 20 31.
KtSJ CHIRAL SYMMETRY AND THE U(l) PROBLEM
by
G.A. Christos Department of Theoretical Physics Research School of Physical Sciences The Australian National University G.P.O. Box 4 Canberra, A.C.T. 2601 Australia
Abstract In the limit of L vanishing quark masses QCD {the theory of the strong interactions) has a global U(L) x U(L) chiral symmetry which is believed to be spontaneously broken down to U(L) vector symmetry. The U(l) problem concerns the apparent absence of a Nambu-Goldstone boson associated with the spontaneous breaking of the U(l) axial symmetry. A 'solution' to this puzzle comes about because the U(l) axial symmetry is afflicted with a Schwinger-Adler-Bell-Jackiw anomaly. The manner in which this happens is complicated and technical. I will review the present status of this subject with an emphasis on recent developments from the point of view of large N (N = number of quark colours) expansion. Some phenomenological applications are also discussed.
21 Session IV Monday 5.00 - 6.00 p.m. 21 32.
RESONANT STRUCTURES IN THE 20Ne(16O,12C)2'fMg REACTION
by
Y. Kondo, B.A. Robson and R. Smith
I Department of Theoretical Physics Research School of Physical Sciences The Australian National University Canberra, Australia 1 Abstract
Gross resonant structures observed in 16O + 2"Ne elastic scattering 20 16 12 21 ie 20 and the Ne( O, C) *Mg (g.s.) reaction for 22.8 < Ec.m. ( O+ Ne) < 38.6 MeV have been studied successfully using an extended optical model" and an exact finite-range (EFR) DWBA approach, respectively. The ion-ion potentials employed include both a real parity-dependent interaction and an angular momentum (J) dependent absorptive term. It is demonstrated that the inclusion of both these terms is essential for the prediction of the four gross structures observed in the 160 + 20Ne elastic scattering excitation function at 9c.m. = 154° , with each of those structures being modelled as a doublet of even parity plus odd parity shape resonances. The doublet structure is a consequence of the parity-dependent interaction and is enhanced by the J-dependent absorptive form. The 160 + 20Ne elastic scattering angular distributions at EC-m- = 24.5, 27.9, 31.7, 32.1, 33.0 and 35.5 MeV are also generally well reproduced. The 12C + 21*Mg potential is determined by fitting available elastic scattering data, with the constraint that the shape resonances of the 12C + 2l*Mg interaction overlap approximately the corresponding 160 + 20Ne shape resonances. EFR-DWBA calculations using optical potentials which describe the elastic scattering data do not reproduce the observed resonant gross structures of the 20 16 12 2t Ne( O, C) *Mg (g.s.) excitation function at 6iab. = 13° . However, it is shown that these gross structures, their previously assigned J^-values 16 2 and the measured angular distribution data at Ec>m>{ 0 + °Ne) = 24.5, 27.9, 31.7, 32.1, 33.0 and 35.5 MeV can be well described by making the optical potentials more surface transparent. This different degree of transparency required to describe the elastic scattering and transfer reaction is discussed.
* > v
22 Session IV Monday 5.00 - 6.00 p.m. 22
i. 33.
THE 58Ni(p,Y)59Cu CROSS SECTIOK AND ITS IMPORTANCE FOR NUCLEOSYNTHESIS
AND STATISTICAL MODEL STUDIES
by
C.I.W. Tingwell, L.W. Mitchell, M.E. Sevior, and D.G. Sargood
School of Physics University of Melbourne Parkville, Victoria 3052, Australia Abstract I One of the most important reactions in determining the abundances of individual isotopes following freeze out from a state of nuclear statistical equilibrium, in supernovae, is 5®Ni(p,y)5^Cu[l]. The cross section of this reaction is therefore of great importance for the theory of nucleosynthesis.
Comparisons of statistical model calculations with experimental data for cross sections of lp,y) reactions on nuclei with a closed shell of 28 neutrons showed the statistical model results to be consistently high by a factor > 2 [2]. It is therefore interesting to see whether a similar effect occurs for nuclei with a closed shell of 28 protons, i.e. the iso- topes of nickel.
Cross section data for 58Ni(p,y)59Cu are presented and their signifi- cance is discussed from the point of view of nucleosynthesis and in terms of the statistical model. In the course of these measurements 60 previously unreported energy levels in 59Cu were observed and their energies have been determined to within i» 1 keV. References >J H;' | [1] D.D. Clayton and S.E. Woosley, Rev.Mod.Phys. 4£ (1974) 755. '; [2] S.R. Kennett, L.W. Mitchell, M.R. Anderson and D.G. Sargood, j Nucl.Phys. A363 (1981) 233.
23 Session IV Monday 5.00 - 6.00 p.m. 23 34.
li INELASTIC SCATTERING OF INTERMEDIATE ENERGY PROTONS FROM TUNGSTEN H by I B. Lay School of Physics if University of Melbourne Parkville, Victoria 3052, Australia Abstract i Inelastic scattering of 134 MeV polarized protons has yielded angular
distributions of cross sections and analysing powers for the J =0 to 6
members of the ground state rotational band of 182W. A coupled channels
analysis with a deformed optical model potential has enabled &2> B deformation parameters to be extracted. Multipole moments have been calculated and compared with existing data, and theoretical predictions of which both are sparse. Data from this analysis are compared with data from similar analyses of 15i*Sm, 166Er and 176Yb, in order to complete a study on these deformed nuclei. I 24 Session IV Monday 5.00 - 6.00 p.m. 24 35. PARITY ADMIXTURES IN THE NUCXEON WAVEFUNCTION by Bruce H. J. McKellar School of Physicsf University of Melbourne, Parkville, Victoria 3052, Australia. Abstract I Just as we have now become accustomed to the weak interactions between \\ * - '.*.*• nucleons producing parity admixtures in nuclear states, Nardulli et al. have 3ss£v." proposed that weak interactions between quarks produce parity admixtures in the nucleon wavefunction. They sought to explain the anomalously large asymmetry in pp scattering at 6 GeV in this way. I point out that the weak nucleon-nucleon potential resulting from this admixture is in conflict with the data on parity non conservation in s-d shell nuclei. 1! IV # 25 Session IV Monday 5.00 - 6.00 p.m. 25 ,i. 36. QCD AND THE SPECTROSCOPY OF QUABKONIA by Richard M. Gorman and Bruce H.J. McKellar School of Physics University of Melbourne Parkville, Victoria 3052, Australia Abstract The spectroscopy of the bound states of heavy quark-antiquark pairs may provide information on some aspects of quantum chromodynainics (QCD), the favoured theory of quark interactions. We use the method of Buchmiiller and Tye to construct a potential extrapolating from a linear form at long range to the short range behaviour described by perturbative QCD, which includes the known effect of one- and two-loop terras and an arbitrary contribution from three loop terms (described by a parameter I). Fitting the resulting spectra to known cc and bb states provides a phenomenological measure of SL and of the QCD scale parameter A—. ! i [ t ,;; 26 Session IV Monday 5.00 - 6.00 p.m. 26 37. AN ANALYTIC DISTORTED WAVE APPROXIMATION FOR INTERMEDIATE EIIERGY PION AND PROTON INELASTIC SCATTERING by F. Pi Marzio and K. Amos School of Physics University of Melbourne Melbourne, Australia. Abstract The inelastic scattering of intermediate energy pions and protons 12 leading to excited states in C is studied within the microscopic framework \k of an Analytic Distorted Wave Approximation (A.D.W.A.)* For pions a Kisslinger form of the ir-N t-matrix in momentum space and an attenuated eikonal for the continuum wave functions are used to derive "analytic" transition amplitudes for both s- and p-waves. In the case of proton inelastic scattering this approach facilitates a transformation of coordinates in the direct two-particle matrix elements and again leads to simple expressions for the central, tensor and spin-orbit transition amplitudes. Predictions are made for the inelastic pion and proton scattering 12 differential cross sections for the excitation of several states in C. The good fits to the experimental data indicate that the A.D.W.A. is both a realistic if and computationally convenient means of testing nuclear spectroscopy and various model two-nucleon t-matrices. Additional calculations are also made for the elastic and inelastic + — 12 (collective model) scattering of K and K mesons from C. 27 Session IV Monday 5.00 - 6.00 p.m. 27 •••*•• 38. THE MEAN-LIFE OF THE SECOND 0* STATE IN 42Ca. P.M. Lewis, A.R. Poletti and M. Savage, Department of Physics, The University of Auckland, Private Bag, Auckland. 42 + The mean-life of the second excited state in Ca (1.84 MeV, 0 ) was measured by the direct electronic timing technique to be 568 i 4 ps, This result compares with a previous measurement^ ' of 480 ± 30 ps which yields a high B(E2) value. The present result gives a B(E2) value of 476 e2^ or 54 single particle units, the theoretical implications of this are discussed. r 2") The accurate mean-life was calculated using Newton's gradient method which assumes that the time spectrum curve can be described as a pure single exponential. This assumption was tested by creating realistic artificial data and comparing the extracted decay constant with that for a pure exponential decay. REFERENCES (1) P.C. Simms; N. Benczer-Koller, C.S. Wu. Phys. Rev. 121_ (1961) 1169. (2) T.D. Newton Phys. Rev. 78. (1950) 490. 28 Session IV Monday 5.00 - 6.00 p.m. 28 39. PHOTONEUTRON CROSS SECTION FOR 12C, 1£*N and 16O by M. Facci, M.N. Thompson School of Physics University of Melbourne Parkville, Victoria 3052, Australia Abstract i The 1I+N photoneutron cross sections of Herman et al. and King et al. Vv' (normalized to join on to the more recent higher energy data of Jury et al. ) show a significant discrepancy. These cross sections are measured by >•• > different methods but should yield the same results below 14.11 MeV. The integrated cross sections up to 14.11 MeV for the preceding cross sections, however, are 3.3 ± 0.3 and 0.737 + 0.009 ifleV - mb respectively. Our work has resolved this difference and to further this work it is t intended to relate the integrated photoneutron cross sections up to a •jt; certain energy for the 3 light nuclei 12C, 14N, and 160. The cross sections for these 3 nuclei all display certain discrepancies. References [1] Berman et al., Phys.Rev. C2, 2318 (1970). ^—--.' 12] King et al., Can.J.Phys. 38_, 231 (1960). t3] Jury et al., Nucl.Phys. R337, 503 (1980). 29 Session IV Monday 5.00 - 6.00 p.m. 29 40. IRREDUCIBLE REPRESENTATIONS OF SUPERALGEBRAS WITH CENTRAL CHARGES by R. Farmer University of Tasmania I To demonstrate the technique of using superfield methods to find irreducible representations of superalgebras by the example of an N=2 extended supersymmetry with one central charge. 30 Session IV Monday 5.00 - 6,00 p.m. 30 &i"'.~.."Vii.* ^*S'J «"'"££» 41. INTRODUCTION TO THE QUANTUM FIELD THEORY OF BAG MODELS by L. R. Dodd, C. A. Hurst and M. A. Lone Department of Mathematical Physics, University of Adelaide, G.P.O. Box 498, Adelaide, SOUTH AUSTRALIA 5001 I Abstract •V-: The usual approach to big models in particle physics can best be described as single particle physics with a touch of interaction, added in an ad-hoc fashion. . •^^VW»*VNI-» The present paper presents an approach which is in consistent quantum field theory language and so in particular permits the definition of space and time translations and rotations in terms of fields defined only over the interior of a bag. This also admits the writing down (if not the solving) of interacting field theories. 31 Session IV Monday 5.00 - 6.00 p.m. 31 42. SOLITON BAGS IN QUANTUM FIELD THEORY by A.G. Williams and R.T. Cahill The Flinders University of South Australia, Bedford Park, South Australia 5042 Abstract Hadrons are extended objects and they are thought to be colour singlet bound states of quarks. For this reason it is important to study extended 1 objects in Quantum Field Theory (QFT). Either one can look for extended objects at the level of the semiclassical approximation for various QFT's of interest (e.g. topological and nontopological solitons), or one can attempt to quantize phenomenological models for hadrons (e.g. the well known MIT, SLAC and Cloudy Bag models). The system of a quartically self-interacting scalar field interacting with a set of fermion fields can be regarded as a primitive model of QCD and has thus received considerable attention in the literature. In particular it has been shown by independent methods [1,2] that soliton bags (also referred to as nontopological solitons) can exist for this system at the semi- classical level. The important thing to note is that the MIT and SLAC bags are just limiting cases of the soliton bags. Using the functional integral representation we have shown that there is a natural connection between the bound states of this QFT, the Green's functions and these soliton bags [3,4,5]. Current efforts are directed toward applying these techniques to more realistic systems. References (1) R. Friedberg and T.D. Lee Phys.Rev.D 15, 1694 (1977) (2) J. Rafelski in "NonJUmaA Equation!, ivTPhy&iu and MathematicA", editor A.0. Barut (Riedel, Dordrecht-HoHand. 1978), p. 399. (3) A.G. Williams and R.T. Cahill, Phys.Rev.D 28, 1966 (1983) (4) R.T. Cahill and A.G. Williams, preprint FIAS-R-114 (to appear in Phys.Rev. D). (5) A.G. Williams and R.T. Cahill, preprint FIAS-R-118. ! t 32 Session IV Monday 5.00 - 6.00 p.m. 32 4 43. VACUUM STRUCTURE IN QCD by C. Roberts and R.T. Cahill The Flinders University of South Australia, Bedford Park, South Australia 5042 :\M- -• Abstract Using the bilocal approximation to the functional integral formulation of QCD, the "vacuum" is defined as the stationary point of the effective ^' k. ;•' bilocal action. The bilocality ensures a Poincare invariant vacuum. The nature of the correlations in the vacuum will be presented. In the condensate theory of hadrons these vacuum correlations determine the bag constant. 33 Session IV Monday 5.00 - 6.00 p.m. 33 '.>.#• • - 44. WEINBERG-SALAM AND BEYOND I C.J. HAMER Department of Theoretical Physics Research School of Physical Sciences The Australian National University G.P.O. Box 4 Canberra, A.C.T. 2601 Australia Abstract A pedestrian's review of the current status of the unified theory of weak and electromagnetic interactions, and of attempts to combine other interactions into a grand unified theory. I if? 34R Session V Tuesday 9.00 - 9.40 a.m. 34R f k 45. UNITARITY AND K-MATRIX MODEL FITTING by B.C. Pearce School of Physical Sciences The Flinders University of South Australia Bedford Park, S.A. 5042 Abstract In recent years interest in the possible existence of dibaryon resonances has been high with experimental evidence [ll showing structure in the 1^2, 3p3 and 'G^ N-N phase shifts and oscillation in the ir-d vector polariz- ation data. Conflicting opinions exist on the interpretation of this data [2,3,4]. The heart of the problem is the difficulty of parametrizing the data in a way that leads to an unabiguous result. The observed structure in the N-N data exist at energies above the pion production threshold, making it a three-body problem. At these energies a correct description of the N-A threshold is essential. Since parametrizing within a full three-body framework is too difficult, an approximation must be made to reduce it to essentially a two-body coupled channels problem. Bhandari et aL[2] used a coupled channel K-matrix model with phase space factors in an attempt to produce a T-matrix with the correct analytic structure i IT (i.e. containing elastic, ir-N-N and N-A thresholds) yet remain amenable to parametrization. By starting with three-body unitarity we are able to derive the model used by Bhandari and illustrate the approximations used to do so. In particular, the expression for disc T™ involves an integral over the N-A channel momentum of |TT.„7 | By making a factorization approximation (which requires assuming 2 is reasonably constant) we can take z |TAf,| out of the integral and arrive' at the same expression for disc T™ as from Bhandari's K-matrix method. ' i1* We applied this formalism to u-d scattering and parametrized the solution of a Faddeev equation calculation (for which we can find the positions of poles by another method). We find that this method predicts poles close to the NA threshold that don't appear in the Faddeev amplitudes. These poles may appear only to compensate for the approximate treatment of the full three-body problem and not actually represent a true resonance of the system. References (1) A. Yokosawa, Phys.Rep. 64 (1980) 47. (2) R. Bhandari, R.A. Arndt, L.D. Roper and B.J. Verwest. Phys.Rev.Lett. 46 (1981) 1111. (3) B.J. Edwards and G.H. Thomas, Phys,Rev. D2£ (1980) 2772. M (4) W.M. Kloet, J.A. Tjon and R.R. Silbar, Phys.Lett. 99B (1981) 80. 35 Session V Tuesday 9.40 - 10.00 a.m. 35 46. LATTICE GAUGE THEORY C.J. HAMER Department of Theoretical Physics Research School of Physical Sciences The Australian National University G.P.O. Box 4 Canberra, A.C.T. 2601 Australia Abstract A review of quantum chromodynamics on a lattice, and of the results of recent Monte Carlo simulations; together with an account of recent progress in Hamiltonian lattice field theory. 36 Session V Tuesday 10.00 - 10.20 a.m. 36 47. PIONEERING WITH HIGH ENERGY HEAVY IONS by Jo Rasmussen University of California Berkeley, California Research with relativistic heavy ions at the Berkeley BEVAIAC will be described, with emphasis on pion production. Spectral irregularities for pions near beam velocity seen accountable by Coulomb mechanisms. Fion bumps near mid-rapidity may arise from quantal orbiting. Recent work at CERN and HSU on subthreshold pion production will be noted. The status of two-pion correlation studies, as a probe of fireball size and lifetime will be reviewed. \ 37R Session VI Tuesday 10.40 - 11.20 a«m. 37R 48. NEUTRON EMISSION FROM ACCELERATING FISSION FRAGMENTS by D.J. Hinde Department of Nuclear Physics, Research School of Physical Sciences, Australian National University, Canberra, ACT 2601. Abstract Fission-neutron angular correlations following fusion of 19F with 232Th (giving 251Es) and 181Ta (giving 200Pb) have been measured. Conventional analysis , based on the approximation that post-fission neutrons originate only from fully-accelerated fission fragments, indicates a larger number of pre-fission neutrons emitted from the compound system 251Es than from 200Pb. This is contrary to expectations based on fission probability systematics or theory. For fission of 25iEs, the gain in excitation energy at scission is A calculation of the number of neutrons emitted during the acceleration of the fission fragments, and their effect on the angular correlation has been made. Using reasonable parameters, it was found that the number was • sufficient to explain the anomalous result. Good agreement with the expected number of pre-fission neutrons from 25*Es could be obtained. This mechanism 2 3 4") must seriously aftect the results of measurements ' ' at high excitation energies, or where the Q-value for fission is favourable. 1) D. Ward et al, Nucl.Phys. A403 (1983) 189, and references therein. 2) E. Cheifetz et al, Phys.Rev. C2 (1970) 256. 3) E. Holub et al, Phys.Rev. C28 (1983) 252. 4) A. Gavron et al, Phys.Rev.Lett. 47 (1981) 1255, 48 (1982) 83S(E). 38 Session VI Tuesday 11.20 - 11.40 a.m. 38 49. GLUON PROPAGATOR IN QUANTUM CHROMODYNAMICS by H.A. Slim Department of Physics University of Western Australia Nedlands HA 6009 Abstract I The gluon propagator in Quantum Chromodynamics is of interest as it is in coordinate space the Born approximation to the Wilson loop potential. A behaviour of the propagator which is more singular than 1/p3 for small momentum p (the infra-red), would lead to a confining static colour potential. Although the gluon propagator is a gauge dependent object it is often the case that particular properties of a gauge theory are manifest in one gauge but not in others. So the infra-red behaviour of ..:'' .i the gluon propagator may contain information about colour confinement. The self-coupling of the gluon field provides the mechanism for confinement. This self-coupling is expressed in the non-linearity of the Dyson-Schwinger equations for the gluon propagator and the presence of the unknown triple - and quadruple - gluon vertices, resp. Y en T., therein. The idea is to truncate this equation in a suitable manner, without spoiling its interesting infra-red behaviour. This can be achieved, following Delbourgo (1) or Baker et al (2), by 'solving* the Slavnov-Taylor identity for F3 in the axial gauge. The truncated equation only contains the propagator as an unknown quantity and its solutions can be studied. An analysis of the equations of Baker et al will be presented. In particular the selfconsistency of a solution with a double pole, i.e. a behaviour like 1/p1* for small p, will be investigated. References f;r.."> • (1) R. Delbourgo, J. Phys. G5 (1979) 603. (2) M. Baker, J.S. Ball and R. Zachariasen, Nucl. Phys. B186 (1981) 531, 560. 39 Session VI Tuesday 11.40 - 12.00 noon 39 50. OCTUPOLE-VIBRATIONAL STATES IN THE EVEN MASS ISOTOPES OF BARIUM by M. Burnett, A.M. Baxter, S. Hinds and F. Pribac Department of Physics, Faculty of Science The Australian National University, Canberra, Australia and R.H. Spear and W.J. Vermeer Department of Nuclear Physics Research School of Physical Sciences The Australian National University, Canberra, Australia Abstract The study of the octupole vibrational (0^=3") states of barium is important both from the point of view of investigating the systanatics of these states as neutrons are removed from the closed N=82 shell and as a testing ground for nuclear theories such as the collective vibrational model and the interacting boson model. It is known that these states are of a collective nature and can be strongly excited by the inelastic scattering of a-particles [1]. We have studied the inelastic scattering of 20-MeV a-particles at a laboratory angle of 174° from 130,132,13^,136 13SBa. In each case a level at 2-3 MeV excitation is strongly populated compared with neighbouring levels. For I3«t,i3e,i38ga this can be identified with a level known from previous work to have »T = 3-. By comparing the angular distribution of scattered a-particles from i30,i32ga w-j£h theoretical coupled channels predictions we hope to positively identify the 3" states in these isotopes. The 13eBa(a,ct')Q+ (ground state), 2+ and 3~ angular distributions have been measured and successfully, fitted using a coupled channels calculation. i32,i3»t,i36,i38Ba nave a-]s0 Deen studied by the inelastic scattering of 40-MeV C12 ions at 90°. At this energy the reaction proceeds pre- dominantly by Coulomb excitation and, from the measured excitation probabilities of the known and putative 3- levels, B(E3, 0+->-3") values have been deduced and these confirm the collective nature of the levels. References t i, [1] R.H. Bassel et al.% Phys. Rev., 128, 2693 (1962). 1 f 40 Session VI Tuesday 12.00 - 12.20 p.m. 40 f •( 51. VARIATION WITH EXCITATION ENERGY OF EVEN-ODD CHARGE EFFECTS IN 252cf FISSION NEUTRON EMISSION by R.L. Walsh Australian Atomic Energy Commission •v • 1 I The question of the existence of even-odd charge effects in neutron emission from 25|Cf spontaneous fission has been the subject of conflicting findings for a decade. The Saclay group has reported no even-odd effects, whereas data of our and other groups show evidence of ii such effects (i.e. fine structure). An ideal way to test whether the fine structure of the Lucas Heights data is real is to examine its dependence on excitation energy. If the amplitude of the fine structure increases as the excitation energy E* decreases, the fine structure is genuine. This test has its precedent in fission mass yield fine structure, for which the trend of increasing amplitude with decreasing E* is well established. Consequently, an extensive re-analysis of the Lucas Heights 252cf(sf) neutron emission data has been made. The method is to set I circular data windows parallel to the contour lines of the kinetic energy versus mass surface. The results show that the neutron emission fine structure increases in amplitude as E decreases and that the structure consist- !l ently occurs at the expected mass locations. The Lucas Heights mass yield data also show this behaviour. Thus the presence of even-odd charge effects in 252Q£ neu'tron emission is confirmed. This result is important for the understanding of de-excitation and pair-breaking mechanisms of the primary fission fragments. 41 Session VII Tuesday 1.20 - 2.00 p.m. 41 i 52. WIGNER COEFFICIENTS FOR SEMI-SIMPLE LIE GROUPS: A PATTERN CALCULUS FOR O(N) AND U(N) ?\ M.D. Gould University of Western Australia I A pattern calculus for deriving reduced Wigner coefficients (RWCs) has been derived by Biedenharn, Louch and collaborators using a technique based on the boson calculus and the so-called factorization lemma. We present an alternative purely algebraic approach to this problem based on the fact that the U(n);U(n-l) RWCs determine polynomial functions of the representation labels of U(n) and U(n-1). By obtaining the zeros of these polynomials, deduced by inspection of the Gel'faud betweeness conditions, we obtain an extension of the pattern calculus. Our approach applies also to the orthogonal groups. t .'• 42 Session VII Tuesday 1.20 - 2.00 p.m. ^*• 53. 168 LONG LIFETIMES AND MOMENTS THROUGH THE BACKBEND IN W by G.D. Dracoulis Department of Nuclear Physics Research School of Physical Sciences Australian National University, Canberra ACT I Lifetimes in W which have been studied recently to high spii. have been measured using the recoil distance method. Two long lifetimes are observed near the backbends. The 14 yrast state has a life time of 38.3 ps and the 12+ yrast state has a life time of 87.4 ps. The 12+ state lifetime results from a retardation factor of 50 of the 12+ to 10+ transition strength compared to the rotational value. The transition quadrupole moments for the observed yrast and yrare states are used to deduce the yrast-yrare interactions of 10 * • 43 Session VII Tuesday 1.20 - 2.00 p.m. 43 54. COULOMB EXCITATION OF THE NUCLEUS 7Li fay W.J. Vermeer, R.H. Spear, M.T. Esat, M.P. Few^ll Department of Nuclear Physics, Research School of Physical Scierces and A.M. Baxter, S, Hinds and S.M. Burnett. Department of Physics, Faculty of Science I Australian National University, Canberra, ACT 2601, Abstract Coulomb excitation of the nucleus 7Li has been studied by scattering 7Li projectiles from targets of 138Ba and 208Pb for a wide range of project- ile energies. The aim was primarily to measure the contribution from virtual excitation of the giant dipole resonance to excitation of the first excited 7 1F state of Li(J = l/2", Ex= 0.478 MeV). Also measured were the B(E2;3/2~->l/2~) value for the transition from the ground state to first excited state, and the ground state static quadrupole moment (Q3/2-)- The latter can be compared with measurements of Q3/2- by atomic techniques as a test of Coulomb excit- ation theory. Results will be presented. ft 44 Session VII Tuesday 1.20 - 2.00 p.m. 44 55. PRE-EQUILIBRIUM CHARGE STATES OF SWIFT CHLORINE IONS IN SOLIDS by H.J. Hay, L.F. Pender and P.B. Treacy Department of Nuclear Physics, Research School of Physical Sciences, Australian National University, Canberra, ACT 2601. Abstract i A study has been made of the approach to charge equilibrium of charge- selected 130 MeV Cl ions incident on a range of self-supporting carbon targets. Outgoing charge distributions were accurately recorded with the iv''"'i focal-plane detector of an Enge spectrograph. Fits to the data were made using a Monte Carlo method using theoretical expressions for capture, loss, excitation and de-excitation. The fits are reasonably consistent with .y, predictions, although there is evidence that standard capture and loss cross sections are inadequate for a full description of charge exchange in the solid. r 45 Session VII Tuesday 1.20 - 2.00 p.m. 56. HIGH SPIN STATES IN Fr NUCLEI by A.P. Byrne*, G.D. Dracoulis*, H. HUbel and R.F. Davie *Department of Nuclear Physics, Research School of Physical Sciences, Australian National University, Canberra, ACT 2601. ISKP, University of Bonn, West Germany. Dept. of Physics, University of Auckland, Auckland, New Zealand. * Abstract The Fr nuclei have five protons outside the closed proton shell (Z = 82). We have studied the three nuclei near the closed (N=126) neutron shell: 2UFr(N=124), 212Fr(N = 125) and 213Fr(N = 126). High spin states have been populated using the reactions 203Tl(13C,5n)2UFr, 205Tl(12C,Sn)212Fr and ZO5Tl(13C,5n)213Fr. Conventional y-ray spectroscopic techniques have been used to establish the decay schemes. The configurations of the lower states are dominated by the alignment of the valence protons in the irhg/2* 1Til3/2 an<* ^7/2 orbitals. The systera- atics of these states are discussed. States have been observed with spins 3 2 above 45/2 -ft. This is the maximum spin available from the [1^9/2^13/2} configuration. For higher spins core excitation of neutrons across the N=126 shell, into high J orbitals, is now energetically favourable . In 2l3Fr it is likely that these core excited configurations intrude into the yrast sequence below the 45/2" isomer. 1) A.P. Byrne and G.D. Dracoulis, Nucl.Phys. A391 (1982) 1. 46 Session VII Tuesday 1.20 - 2.00 p.m. 46 57. POLARIZATION TRANSFER TO INNER-VACANCIES OF IONS SWIFTLY TRAVERSING POLARIZED ION HOSTS by Andrew E. Stuchbery Department of Nuclear Physics, Research School of Physical Sciences, Australian National University, Canberra, ACT 2601. Abstract The transient magnetic field (TF) which acts at the nuclei of ions I swiftly traversing polarized ferromagnetic hosts has drawn considerable inter- est in recent years both as a tool for measurement of nuclear g-factors and as an interesting phenomenon in itself. This paper is concerned with the mechanisms by which the polarization of the ferromagnet is transferred to inner-shell vacancies of the moving ion. Measurements of the K-shell polarization for 0 ions traversing Fe have been reported recently . The K-shell polarization observed at oxygen veloc- ities between %Zvo and Zvo (v0 = Bohr velocity) cannot be explained by the two-step mechanism which is held to account for that observed at lower ion velocities . A mechanism which can explain the higher velocity polarization is proposed. This mechanism depends on the adjustment of the 0 K-shell and 0 the Fe L-shell toward those of the united atom during collisions between 0 ions and Fe atoms, allowing direct transfer of polarized Fe M-shell electrons to the 0 K-shell up to ion velocities of ^8vo. For arbitrary ions travers- ing Fe this mechanism suggests an inner-vacancy polarization constant with ion velocity up to >^8v0. Above 8v0 the polarization is predicted to dimin- ish rapidly with increasing ion velocity (due to dominant capture of unpolar- ized L-shell electrons). As a consequence, the TF strength is predicted to diminish with increasing ion velocity above ^ 8vo for all ions traversing Fe hosts. il: 1) A. Becker et al, Hyp.Int. 11 (1981) 279. 2) K. Dybdal, J.S. Forster and N. Rud, Nucl.Instr.Meth. 170 (1980) 233. fv 47 Session VII Tuesday 1.20 - 2.00 p.m. 47 58. STUDIES OF VERY NEUTRON-RICH LIGHT NUCLEI USING A GAS TARGET by M.A.C. Hotchkis, P.V. Drumm, L.K. Fifield, T.R, Ophel, D.C. Weisser and C.L. Woods Department of Nuclear Physics, Research School of Physical Sciences, Australian National University, Canberra, ACT 2601. I Abstract A small gas cell, located at the target position of the Enge split-pole spectrometer, has been used to obtain mass measurements for the T £ 3 nuclei 4OC1, 39S and ^Cl. The "°C1 nuclei were produced by the reaction 4oAr(7Li,7Be)1+0Cl at a beam energy of 54 MeV, and the energy resolution of 180 keV was sufficient to permit the identification of a number of excited states of ^Cl. The 39S and UC1 were produced by the 40Ar(18O,19Ne)39S and l*0Ar(180,17F)l*1Cl reactions at a beam energy of 110 MeV. A target gas pressure of 100 Torr was typically employed in these measurements, which corresponded to an effective target thickness of *> 250 ug/cm2. Reaction products were detected and identified at the focal plane of the magnetic spectrometer which was positioned at either 15° or 17.5° to the beam direct- ion. 48 Session VII Tuesday 1.20 - 2.00 p.m. 48 j' '""•• ~~^ 59. 1 PARITY-DEPENDENCE OF THE NUCLEUS-NUCLEUS POTENTIAL AND 16O + 2"Mg ELASTIC SCATTERING AT 6 _ = 90° cm. by Y. Kondo, B.A. Robson and R. Smith Department of Theoretical Physics Research School of Physical Sciences The Australian National University Canberra, Australia I and J. Nurzynski, P.V. Drumm, T.R. Ophel and D.F. Hebbard Department of Nuclear Physics i#4' Research School of Physical Sciences The Australian National University Canberra, Australia Abstract Recently it has been demonstrated [1] that each gross resonant 2i| 16 12 28 - i J structure observed in the Mg( O, C) Si (g.s.) reaction for 26 < Ecm_ < 52 MeV can be modelled as a doublet of even plus odd parity shape" resonances in the entrance 16O + 21*Mg channel. Such doublets of shape resonances arise naturally as a consequence of parity dependence of the nucleus-nucleus potential. Ambiguity in the present spin assignments of these resonant structures, however, results in a possible uncertainty in the modelling, which is reflected in an uncertainty i,n the sign of the parity-dependent potential. Since elastic scattering of spinless particles at 9c.m. = 90° is sensitive to even partial waves only, measurement of the 90° elastic scattering excitation function for the 160 * 2<4Mg system yields valuable information on the position of J = even shape resonances , which provides additional constraints on the sign and magnitude of the parity-dependent part of the nucleus-nucleus potential. Experimental data and theoretical analysis will be reported. [1] B.A. Robson and R. Smith, Physics Letters 123B (1983) 160. 49 Session VII Tuesday 1.20 - 2.00 p.m. 49 60. PROTON INDUCED REACTIONS ON 37C£ t AND THEIR RELEVANCE TO NUCLEOSYNTHESIS '- -4 by R.O. Weber, L.W. Mitchell, M.E. Sevior, C.I.W. Tingwell, and D.G. Sargood School of Physics, University of Melbourne, Parkville, Victoria 3052, Australia. Abstract The reactions 37CJl(p,Y) 38Ar, 37C£(p,n)37Ar, and 37CJUp,a)3t *S, or their inverses, feature in the mainstream of nucleosynthesis in hydrostatic sili- con burning and explosive oxygen burning in massive stars. Measurements of i i their cross sections are therefore astrophysically interesting. Because the 37CJl(p,n) threshold occurs at a low bombarding energy, namely 1.60 MeV (cm.), this set of reactions provides an excellent medium for the study of competition effects between different channels in the con- text of the statistical model of nuclear reactions. For both these reasons the cross sections of these reactions have been measured and the data are presented for bombarding energies from 0.59 to 2.07 MeV for the (p,y) and (P/Oiy) reactions and from threshold to 2.42 MeV for the (p,n) reaction. In all cases the data are compared with the predic- i tions of the statistical model code HAUSER*4[1]. Agreement is good for the (p,ay) data but the code overestimates the (p,y) and (p,n) data by factors •v 2. Thermonuclear reaction rates have been determined from the data for the reactions studied and also for the inverse reactions 3**S(ot,p) 37C£ and 37Ar(n,p)37C£ over the temperature range (1 - 10) * 109K. The rates are in very mixed agreement with those currently used in nucleosynthesis calcula- tions [2]. The contribution to the rates of 37C£(p,y)38Ar from protons in the energy range 0.7 - 1.8 MeV has also been calculated and compared with rates calculated from published resonance strength data in this energy range[3]. The agreement is excellent. References [1] F.M. Mann, Hanford Engineering and Development Lab. Rep. No. HEDL-TME- 7680 (1976). [2] S.E. Woosley, W.A. Fowler, J.A. Holmes, and B. Zimmerman, Caltech preprint OAP-422 (1975). [3] P.G. Alderliesten, A.M. Aerts, H.M.J. van Bijlert, and C. van der Leun, Nucl.Phys. A220 (1974) 284. 50 Session VII Tuesday 1.20 - 2.00 p.m. 50 61. LOCALIZED St. WINDOW PROM PARTIAL FUSION REACTIONS ACCOMPANIED BY PROTON, DEUTERON, AND TRITON EMISSION by H. Yamada School of Physics, University of Melbourne, Parkville, Victoria 3052, Australia. Abstract A high and localized spin population associated with partial fusion reactions has been established through the measurement of y-ray multiplicity in coincidence with fast forward p, d, or t produced by 167-MeV 1HN on 15l*Sin. The average Y multiplicities are constant (M = 31) for all the yrast transitions up to spin 26h in 158Er, which implies that no spins up to 26h were populated initially. The deduced average angular momentum transferred is 63ft, which is comparable to the critical angular momentum I predicted for the fusion of 13C and 15£fSm. The mass distribution of the residual nuclei is appreciably narrower than that for compound nuclear reactions, and this gives another indication of the narrow d window. References [1] Phys.Rev. C24, 6 (1981) 2565. 51 Session VII Tuesday 1.20 - 2.00 p.m. 51 62. SPIN DEPENDENT EFFECTS IN PION-NUCLEUS SCATTERING by Lindsay Berge Theory Group School of Physics University of Melbourne Parkvil1e.Australi a Abstract The Kisslinger Optical Potential is widely used in co-ordinate space calculations of pion-nucleus elastic and inelastic scattering [lj. This potential form has been elaborated to include spin-dependent terms [2] and thus may be used with microscopic nuclear structure to describe scattering involving unnatural parity transitions. It is also possible to determine the contribution of spin-dependent terms in natural parity transitions. The distorted wave code DWPI [3] has been modified to use this potential and differential cross-sections have been calculated which may be compared to experimental data. Potential coefficients may be obtained from free pion-nucleon phase shifts or off-shell interaction models. References [1] Auerbach,Fleming & Sternheint, Phys.Rev. 162 (1967) 1683 [2] Koltun, "Advances in Nuclear Physics" Vol.3', Plenum Press (1969) [3] Eisenstein & Miller, Comp.Phys.Comm. 11 (1976) 95 52 Session VII Tuesday 1.20 - 2.00 p.m. 52 - • r 63. PHOTONEUTRON REACTION CROSS SECTIONS OF 121Sb, 123Sb and Nat. Sb R.P. Rassool, D. Orr and M.N. Thompson School of Physics University of Melbourne Parkville, Victoria 3052, Australia Abstract i The reaction cross sections of 121Sb(y»n), 123Sb(y,xn) and Nat. Sb(Y,xn) have been measured in the energy range 8 to 24 MeV. The 121Sb measurement was obtained by activation using bremsstrahlung. The *23sb and the Nat. Sb photoneutron reaction cross sections were obtained by directly counting neutrons as a function of bremsstrahlung tip energy. Results are consistent with the predictions of collective models for oblate (negatively) deformed nuclei. Applicability of the Hydrodynamic collective model as describing the observed structure and broadening of the Giant Dipole resonance is discussed. A comparison is also made with the Dynamic collective model predictions for oblate nuclei. I 53 Session VII Tuesday 1.20 - 2.00 p.m. 53 64. THE ^8Ca(Y>+p) PHOTONUCLEAR CROSS SECTION IN THE GIANT DIPOLE RESONANCE REGION by G. J. O'KEEFE. Y. I. ASSAFIRI, M. N. THOMPSON BETATRON LABORATORY SCHOOL OP PHYSICS UNIVERSITY OF MELBOURNE PABKVILLE, AUSTRALIA Abstract I The ^Ca(tf,n+p) cross section has been measured from neutron threshold to 25.0 MeV using the activation technique spanning the Giant Dipole Resonance(GDR) region. A measurement of the Ca(y,p) cross section is used to obtain the * Ca(y,n) cross section. From this the ^8Ca(J'',2n) cross section is estimated from a statistical calculation. An estimate to the total photoabsorption for this energy- range is then made. The results are discussed in terms of the statistical decay of the GDR with the inclusion of isospin effects according to the predictions of Goulard and Fallieros. 16 20 I f ENERGY (MeV) ' I- 54 Session VII Tuesday 1.20 - 2.00 p.m. 54 65. PARTICLE-HOLE DESCRIPTION OF THE NUCLEAR • !•''• - . , GIANT DIPOLE RESONANCE IN LIGHT-TO-MEDIUM NUCLEI by Y. I. ASSAFIRI AND I. MORRISON School of Physics, University of Melbourne, Parkville, Vic. 3052, Australia ABSTRACT The particle-hole model is presented for nuclei with closed core ± 2 nucleons. This model was partly exploited by Cooper and Eisenberg for three-particle/one-hole (and conjugate) states. The resulting expressions involved in the formalism given by Cooper and Eisenberg (1) were specifically formulated to the odd-parity problem in 6Li and ^N, where the three-particle (three- hole) system was restricted to the lp shell, hence at least two particles (two holes) were assigned equal (n£j) quantum numbers. This restriction is now lifted in this work, where the reported expressions have general applicability to calculations involving M f particles (holes) in the 2s-ld and higher shells. Two methods for spurious states removal are presented. Both methods were applied as a check on our calculation. Application of this calculation is presented forthe non-normal parity low-lying and GDR states in 6Li, 1 ItC and 180. REFERENCES (1) B.S.Cooper and J.M.Eisenberg, Nucl. Phys. A114(1968)184. f 55 Session VII Tuesday 1.20 - 2.00 p.m. 55 66. The Pn Channel and the Effects of Crossing Symmetry by R.J. McLeod School of Physical Sciences The Flinders University of South Australia Bedford Park, S.A. 5042. I Abstract The effect of crossing symmetry on the Pa channel is investigated. The Pn channel is of considerable interest to nuclear physics since it contains the nucleon pole, by which true absorption takes place, and the Roper resonance. The phase shifts start off negative and changes sign at a center of mass momentum of k=1.5 m^. They continue to rise going through the Roper resonance at k=3.0 1%. Models are constructed that reproduce the phases in this channel for use in three-body and pion-nucleous calculations. These models do not include crossing symmetry. Potential models are not crossing symmetric by construction and in field theoretic models, crossing makes the equations non-linear and thus difficult to deal with. Recently, a rigorous solution to the crossing symmetric Low equation in the static limit was reported1. This work solved the Chew-Low model as extended by Ernst and Johnson2. We use the results of this calculation to examine effects of crossing in the P11 channel. Simple field theoretic models do not contain enough attraction to give rise to the observed change in sign observed in the Pn. We add a p exchange and the delta graph to the pion-nucleon S and U channel poles. We use this along with the contribution from crossing to drive a single channel N/D calculation. By adjusting the parameters, the phase shifts are reproduced quite well below k=4.5 m^. With this fit, crossing contributes 25% of the total attraction that cancels the repulsive pion-nucleon Born terms. At the Roper resonance, the crossing contribution is still 20% of .1 the attraction part of the amplitude. From this study, it is clear that crossing symmetry must be included I; for an accurate description of the Pn channel at low and intermediate energies. We expect these results to persist after relativistic corrections have been made. if References (1) R.J. McLeod and D.J. Ernst, Phys. Lett. 119B, 277 (1982). (2) D.J. Ernst and M.B. Johnson, Phys. Rev. C17, 247 (1978). 56 Session VII Tuesday 1.20 - 2.00 p.m. 56 67. COMPARISON OF NEUTRON-DEUTERON AND PROTON-DEUTERON ANALYSING POWERS R. Garrett and A. Chisholm Physics Department, University of Auckland, New Zealand I ABSTRACT Nucleon deuteron data are usually analysed in terms of calculat- ions of the Paddeev type. Such calculations are usually strictly for the neutron-deuteron system rather than for the proton-deuteron system, because of the difficulty of including the Coulomb interact- ion in the three body calculations. On the other hand, until recently, the most accurate nucleon polarization data has come from proton-deuteron experiments. There is therefore a clear need for a method of including Coulomb effects in the three body calculations. Neutron-deuteron analysing power measurements are now being done with an accuracy approaching that of the proton-deuteron experiments. There are significant differences between the n - d and p - d measure- ments. These experiments could tell us something about charge- ;•'. symmetry breaking in the nucleon-nucleon interaction, but only after Coulomb effects have been allowed for. We present comparisons of n - d and p - d analysing power measure- ments from various sources. Problems that arise in making the comparisons are discussed. 57 Session VII Tuesday 1.20 - 2.00 p.m. 68. LOCATION OF 3p-3h STRENGTH IN 16N VIA THE REACTION 13C(a,p)16N at 118 MeV by P.R. Andrews.. B.M. Spicer, G.G. Shute, V.C. Officer STF. Collins, and J.M.R. Wastell School of Physics University of Melbourne Parkviller Victoria 3052, Australia and H. Nann, D.W. Devins, W.P. Jones, C. Olmer, Qingli Li I Indiana University Cyclotron Facility Milo B Sampson Lane Blocmington, IN 47405 U.S.A. Abstract Differential cross sections of proton groups corresponding tc excited states in 16N were measured in the reaction 13C(a,p)16N at 118 MeV. Strongly populated states at 11.21 MeV and 11.81 MeV have been assigned spins J = 6 and J = 7 respectively. Evidence was obtained for the splitting of the lp-lh j" = 4~,T=1 strength in 16N on the basis of DWBA calculations incorporating three nucleon microscopic form factors. The addition of a 3p-3h component of 16% was required to fit the data to the known J71 = 4~ state at 6.168 MeV. 58 Session VII Tuesday 1.20 - 2.00 p.m. 58 69. THE J|OCa(p,pd)38K AND *»0Ca by J.M.R. Wastell, B.M. Spicer, G.G* Shute (University of Melbourne), P.X. Schwandt, D.W. Devins, B.S. Flanders, D.L. Friesel, W.P.. Jones, Cheu Shen, L.C. Welch (IUCF), A.A. Cowley, S.J. Mills and J.J. Lawrie (National Accelerator Centre, South Africa). Abstract We measured cross-sections for the IfOCa(p,pd)38K and 4t)Ca(p,2p)39K reactions at 150 MeV in a coplanar geometry using two hyper-pure germanium detector telescopes* Data were obtained for both symmetric and asymmetric angle pairs in an attempt to distinguish between various phase equivalent optical model potentials by measuring the behaviour of a ratio of cross-sections as a function of energy sharing parameter X. The results of this test will be discussed. In addition, triple-differential cross-sections for deuteron and proton knock-out from ^Ca will ba compared with distorted wave impulse approximation calculations. The deuteron knock-out data was an unexpected bonus obtained from a sophisticated data sorting/dinplay computer program developed at Melbourne* Brief comments on this program may be made. 59 Session VII Tuesday 1.20 - 2.00 p.m. 59 jtyj-irrawori .. -..!•"(. ;.:?:..•";.,; o.- 70. PHOTONUCLEAR RKACTIONS IN LIGHT NUCLEI by M.M. Thompson School of Physics University of Melbourne Parkville, Victoria 3052, Australia Abstract I Photons provide a soft probe of the nucleus, that over many years have contributed to our understanding of the nuclear force. Recent high resolution studies of different decay channels of the Giant Dipole Resonance (GDR) have led to a clearer understanding of the role of isospin in the GDR region. Studies of inverse reactions are also clarifying the mechanisms involved in the photonuclear process. In particular the role of secondary doorway states has become evident in photonuclear reactions in several light nuclei. 60R Session VIII Tuesday 2.00 - 2.40 p.m. 60R 71. DIRECT REACTION ANALYSIS OF HEAVY ION COLLISION FROM THE QUASI-ELASTIC TO THE DEEP-INELASTIC REGIME by H. Lenske, S. Landowne and H.H. Wolter Sektion Physik, Universitat Miinchen, Garching, Germany and I T. Tamura and T. Udagawa Department of Physics, University of Texas, Austin, Texas, U.S.A. Abstract Recently attempts have been made to extend the application of direct reaction theory into the continuum, thereby providing a unified quantum- mechanical description of reactions from the quasi-elastic to the deep- inelastic regime. The multistep direct reaction (MSDR) approach, formulated by Tamura et al. [1] and applied mainly to light ion induced reactions, is used here to describe heavy ion inelastic scattering with large energy loss. The basic direct reaction mode is assumed to be the excitation of correlated ph-phonons. Statistical arguments lead to the conclusion that the t transition to the continuum can be described as the incoherent and independent excitation of such phonons. In the present calculation up to two steps have been considered. The transition strength functions are calculated by the RPA response function method. The approach has been applied [2] to the ^Tif^O, 160') reaction at Elab = 100 MeV , for which double differential cross sections and polar- izations of the residual nuclei have been measured [3]. We find, that the data are well reproduced by the present calculation for energy losses up to about 20 MeV. The two-step mechanism dominates the cross section for energy losses of more that about 8 MeV. This is encouraging, because it suggests that by considering more steps one will be able to describe reactions with still higher energy losses. Investigations are underway in this direction. n! [1] T. Tamura et al., Phys. Rev. C26 (1982) 379. [2] H. Lenske et al., Phys. Lett. 112B (1983) 333. [3] W. Trautmann et al., Bormio 1981 and to be published. 61 Session VIII Tuesday 2.40 - 3.00 p. 72. A NUCLEAR PHYSICS PROGRAMME WITH THE PROPOSED 8MV TANDEM ACCELERATOR AT LUCAS HEIGHTS by J.W. Boldeman Australian Atomic Energy Commission It is proposed that a high-technology, multi-user facility based on an 8 MV tandem accelerator be installed by the AAEC to provide new capabilities in the following fields: (a) Radioisotope dating and ultra-sensitive trace element determination in isotope hydrology, salinity, sedimentology, erosion, actinide transport and materials studies; (b) Physics studies required for the development of methods of applying nuclear materials safeguards, the provision of neutron dosimetry standards, measurements of precision data for radiation interactions and the development of new methods for radioisotope dating; (c) Development of nuclear and ion techniques with applications in occupational health, biomedicine, materials modification, quaternary studies, industrial problems and other fields; (d) Special requirements for accelerator-based radiocarbon dating of geological and archaeological samples not being met by other laboratories, coordinated by the Australian National University; These primary objectives include collaborative projects with BMR, NSW Water Resources Commission and, through the auspices of A1NSE, with Australian Universities and advanced educational institutions. Existing inter-regional programs in hydrology and neutron physics would also be served by the proposed facility making possible an expansion in the scope of joint projects with other countries in the SE Asian region. Specific aspects of programs (a) to (c) would receive priority for initial use of the facility within AAEC resources. The proposed experimental program and the wide range of possible additional applications is discussed. 62R Session IX Tuesday 3.20 - 4.00 62R 73. THE 17O(r,n) CROSS SECTION by D. Zubanov*, M.N. Thompson*, B.L. Berman**, R.E. Pywellt, J.W. Juryxx, and K.G. McNeilloo Abstract Results of a measurement of the 17O(y»p) reaction made using quasi- monoenergetic photons from annihilation of positrons in flight will be pre- sented. The reaction yield was determined from the 6.13 MeV gamma rays follow- ing from the 7.13 second half-life beta decay of the residual 16N. Using two large (Il"x5!2" and 8"x8") Nal detectors. These were placed either side of the sample position so that induced activity could be detected from the sample between beam bursts. The sample consisted of 3.06 mole of 170 in the form of water. This sample was contaminated with 1.74 mole of 18O, and since the 180(Y»np) reaction also leads to 15N, it was necessary to measure this contaminant reaction using a separate 180-water sample. This separate experiment in fact provides the first measurement of the 180(y,np) cross section. At each annihilation photon energy, a spectrum was recorded from each detector. From these spectra, the total 6.13 MeV response, per unit photon dose was determined and plotted as a function of incident photon energy after background correction dose normalization and correction for the bremsstrahlung contribution. The most notable and unexpected feature of the cross section is the very large and narrow peak at about 15 MeV, only 1.2 MeV above the reaction :. threshold. Interpretation of this feature is not clear, but it is probably one or a few T=3/2 states in 17O isospin-forbidden to decay to low-lying states in 16O by neutron emission. Closer examination shows a general correlation between the features seem in this cross section and that of the photoneutron reaction. However there are significant differences in the relative strengths of some of the peaks. The peak of the GDR as revealed in the photoproton cross section is at 22 MeV, while in the neutron decay cross section it appears at 23 MeV. The ratio of photoproton to photoneutron cross sections depends on isospin considerations and this will be discussed. * School of Physics, University of Melbourne, Parkville, Vic, 3052, Aust. ** Lawrence Livermore National Laboratory, Uni. of California, Livermore, California, U.S.A. t Physics Dept., Uni. of Saskatchewan, Saskatoon, Saskatchewan, Candad. xx Physics Dept., Trent University, Peterborough, Ontario Canada, %r oo Physics Dept., Toronto University, Toronto, Ontario Canada. 63 Session IX Tuesday 4.00 - A.20 p.m. 63 74. Medium Corrections in Inelastic Proton Scattering at Intermediate Energies by W. Bauhoff School of Physics University of Melbourne Parkville, Australia Abstract I An important ingredient in the microscopic description of inelastic proton scattering is the interaction between projectile and target nucleon which promotes the excitation. For high bombarding energies, the free nucleon-nucleon interaction can be used. For lower energies (up to about 400 MeV), modifications of the free interaction have to be taken into account, arising from the presence of the nuclear medium, this requiring the introduction of an effective interaction. It can be calculated for the case of a nucleon impinging on infinite nuclear matter in lowest order Brueckner theory by solving a Bethe-Goldstone equation, starting from a nucleon-nucleon potential. The transition to finite nuclei is then made in a local density approximation. Such calculations have been performed starting from the Hamada-Johnston potential and the more recent Paris potential. Various components of the calculated t-matrices inside nuclear matter are influenced differently by the medium, the effect being large for the non spin-flip components of the central force. This selective modification of the t-matrix components leads to effects of varying strength in the excitation of nuclear states with different spin-isospin quantum numbers. Specifically, for isoscalar natural parity states, a reduction of the peak cross-section and an enhancement for larger angles is predicted, compared to the results obtained with the free t-matrix. The predictions of the theory are confronted with experimental data in the energy range 25-400 MeV. Of special interest is tk«* scattering off 12C, where data exist over a large energy range and for all spin-isospin combinations, and off 208Pb where large scale RPA wave functions are available for the nuclear states of interest. Improved agreement with experiment is obtained for bombarding energies above 100 MeV compared to a description without medium corrections. Agreement with experiment is also obtained for energies as low as 25 MeV where previously real effective forces based on the G-matrix have been used. The medium corrections lead to a reduction of the transition potential in the nuclear interior where the density is high. The transition potential gets thus more surface-peaked and resembles the usual collective model form- factor. The effect is most pronounced for the imaginary part of the form- factor. • • This work has been supported by the Australian Research Grant Scheme. 64 Session IX Tuesday 4.20 - 4.40 p.m. 64 75. COSMOLOGICAL CONSTRAINTS ON HEAVY NEUTRINO LIFETIMES by H. Granek and B.H.J. McKellar School of Physics University of Melbourne Parkville, Victoria 3052, Australia Jf Abstract Neutrinos with masses in the range 2 MeV < m < 100 eV, if they VH exist, would need to be unstable in order that their present mass density does not exceed the experimental bounds. Two modes of decay are considered, an the radiative v •*• v v & purely leptonic v •* 3vT where v is the heavy neutrino and v a light one. Significant amounts of radiation released from L heavy neutrinos decay will distort the microwave background. The amount of radiation released may be limited if only a fraction of B the heavy neutrinos decay using the radiative mode. The resulting limits on the branching ratio B for different values of the mass and lifetime of the heavy neutrinos will be presented. 65 Session IX Tuesday 4.40 - 5.00 p.m. 65 76. 1 THE FUTURE OP APPLIED NUCLEAR PHYSICS -/ by G.J.F. Legge School of Physics University of Melbourne Parkville, Victoria 3052, Australia Abstract This review will look at recent trends, in Australia and overseas, I where many nuclear physics laboratories are becoming increasingly involved in applications of nuclear techniques to other scientific or technological fields. In consideration of the reasons for this activity, particular emphasis will be placed on work with ion beam analysis and comparisons will be made with competing techniques. Recent progress will be reviewed i ; and some comments made on likely developments in the future. i \ I I1' 66R Session X Wednesday 9.00 - 9.40 a.m. 66R 77. QUADRUPOLE MOMENTS OF THE 12 ISOMERS IN MERCURY 188 AND MERCURY 190 by G.Do Dracoulis Department of Nuclear Physics Research School of Physical Sciences I Australian National University, Canberra ACT + 188 190 The quadrupole moments of the 12 isomers in Hg and Hg, which have half lives of 130 and 21 ns respectively, have been measured. The nuclei were excited and aligned using (heavy ion, xn) reactions with pulsed beams from the B.NUL. NP tandem accelerator facility. The excited nuclei were implanted into solid crystalline mercury hosts and the modulation of the gamma ray angular distributions due to the precession of the nuclear spin in the electric field gradient of the non-cubic crystal lattice observed as a function of time. The quadrupole couple constants were deduced from the known value for 199ng (for the Hg(Hg) system) and the quadrupole moment extracted. The results indicate a gamma deformation for the light mercury isotopes, induced by the alignment of the ii3/9 neutron quasi particles. ' ft.. iK . 67 67 Session X Wednesday 9.40 - 10.00 a.m. 78. THE FUTURE OF COSMIC RAY PHYSICS by C.B.A. McCusker Falkiner Nuclear Physics Department, School of Physics, University of Sydney, N.S.W. 2006. Abstract The energies of cosmic ray primary particles can vary from an arbitrary lower limit, generally set at 108eV, to, at least, 1021eV. There is no evidence that this is an upper limit. The greater the energy, the fewer the number of particles. Above 1017eV the differential energy spectrum falls off approximately as 1/E3. Between 1010 and 1014eV it is easy to determine the nature of the great majority of the particles, using detectors flown close to the top of the atmosphere. They are stripped nuclei of all elements from H through U. Hydrogen is the commonest; elements between hydrogen and iron (including iron) occur fairly frequently; elements beyond iron occur but in 1 numbers down by a factor of ^10^ on iron. The composition appears to change above ^5xl0l4eV. The energy spectrum also shows marked steepening. There is now considerable evidence that super dense globs of quark matter make their appearance in this region and result in a beam of free quarks reaching sea level. Its intensity is ^8xlO~12 quarks per cm2 sec sr. The investigation of the properties of these particles is one of the main prospects open to cosmic ray research. A second major field is the study of unusual events found deep under- ground by groups operating in India and Japan. A third field (which overlaps on the first) is the study of events in the range 1014 - lOl'eV using large emulsion chambers at M8.000 feet above sea level, or air shower core detectors at sea level. One particularly interesting phenomenon here (apart from the quarked globs) is the study of 'geminions' or 'double cored showers1. A fourth possibility of great interest is the Deep Underwater Muon and Neutrino Detector (DUMAND). i ; 68R Session XI Wednesday 10.20 - 11.00 a.m. 68 R '*•' '• 79. COMPOSITION OF COSMIC RADIATION FOR ENERGIES OF MORE THAN lOOTeV M.M. Minn Faikiner Nuclear Department, School of Physics, University of Sydney. N.S.W. 2006. Abstract The composition of primary cosmic ray particles can be characterized by mass or charge. Either way is acceptable as the particles are likely to be fully stripped atoms. For particles of <_ lOOTeV, particle tracks can be recorded in photographic emulsions or other detectors and the charge Z of an individual particle is then obtainable from the ionization loss in the detector (energy loss proportional to Z2). The steeply descending nature of the cosmic ray energy spectrum limits this method to £lOOTeV. In addition, the detectors have to be operated at the top of or above the earth's atmosphere. Detector areas of ^lm? are needed. For primary particles of >100Tev, low fluxes necessitate detector areas of ';l00m2 and the areas would have to progressively increased for higher energies. A detector of this size is clearly impossible at the atmosphere's top. The only solution to this problem lies in observing the air shouer produced by the primary particle. To the first approximation, an air shower due to a primary of mass A resembles A superposed showers dueto protons. One then might expect that the secondary particles in showers caused by primaries of mass A, (A>1), will have lower energies than the secondaries in showers due to protons. This is providing the two primaries have equal total energy, this energy being more widely shared in the first case. , ! The "sharing" effect should be less pronounced in the "tail" end of a shower where particles are "dropping" out of the cascade process due to i ionization loss. We should confine attention to the start of the shower where energy sharing is important. Even then a diminution of the sharing effect will occur due to the increase of multiplicity as particle energies increase. An extra complication arises because the measurements are done per force at ground level, several particle generations down from the showers' start. Despite these and other problems it is (in principle) possible to obtain primary mass information from the energy spectra of energetic shower particles at ground level. However low particle fluxes and energy resolution problems made the job difficult. Another approach is to examine, with high spatial resolution and over a 'UOm2 area, the spatial density distribution of all the charged particles in the air shower at ground level near to the prolongation of the primary particle's path. Such distributions can be characterized taxonomically to produce indicators of primary mass. This relies on understanding the complex shower processes in some detail - artificial showers are generated by monte carlo methods and compared with real ones. Work in various parts of the world on this subject will be discussed. 69 Session XI Wednesday 11.00 - 11.20 a.m. 69 80. VARIATIONS OF THE GYROMAGNETIC RATIOS OF CORRESPONDING STATES IN 188>190>192Os; MEASUREMENTS AND INTERPRETATIONS by A.E. Stuchbery, H.H. Bolotin, I. Morrison, L. Wood and*R. Bark * Department of Nuclear Physics, A.N.U. School of Physics, University of Melbourne, Parkville, Victoria 3052, Australia Abstract The gyromagnetic ratios of the 2*, 2*, and 4* levels in i<»8,i90,i92Os were experimentally determined utilizing the enhanced transient magnetic hyperfine field following Coulomb excitation of the states of interest by beams of 220-MeV 58Ni ions from the Australian National University 14UD Pelletron tandem accelerator. Corresponding states in the three nuclides display sizable variations in their measured g-factors and, of considerable interest, the measured ratio g(22)/g(2,) in the three isotopes studied are significantly disparate. These variations in the measured g-factors of the levels in the two low-lying bands in the three nuclides will be compared with interacting boson approximation model-based calculations, as well as with a Nilsson basis single-particle model description. Session XI Wednesday 11.20 - 11.40 a.m. * " 81. El DECAY OF THE FIRST EXCITED STATE OF 9Be I F.C. BARKER Department of Theoretical Physics Research School of Physical Sciences The Australian National University G.P.O. Box 4 Canberra, A.C.T. 2601 Australia Abstract The first excited state of Be is slightly unbound for breakup into 8,Be ground state plus an s-wave neutron. In a recent calculation of the strength of the El decay of this state, Millener et al. [Phys. Rev. C28 (1983) 497] treated the state as bound and calculated the strength as a function of the binding energy. We show that extrapolation to the energy of the unbound state is meaningless, because of the singular properties possessed by an s-wave neutron threshold. When the state is correctly treated as unbound, the calculated strength is appreciably greater than the measured value, as is also the case for other strong El transitions between bound states in Be and 13C. ("i* 7\ Session XI Wednesday 11.40 - 12.00 noon 71 ;?-*• tr-, ...,Zii? ; ,\i,./ 82. l\ r The Reaction at 80 MeV by S.M. Banks, B.M. Splcer, G.G. Shute and V.C. Officer I School of Physics, University of Melbourne, Parkvllle, Victoria, 3052 G.J. Wagner Max-Planck-Instltut fur Kernphysik, 6900 Heidelberg, Germany W.E. Dollhopf Physics Dept, Wittenberg University, Springfield, Ohio, 45601, U.S.A Li Qlngli, C.W. Glover, D.W. Devins and D.L. Friesel Indiana University Cyclotron Facility, Bloomington, Indiana, 47405, U.S.A. Abstract The results of a 48Ca(J,fye)1*^ reaction using 80 MeV vector polarized f deuterons obtained from the Indiana University Cyclotron Facility will be presented. The use of vector polarized deuterons allows measurements of analysing powers as well as differential cross sections to be made, and these In turn help in distinguishing between j»JM-l/2 and j-Jl-1/2 proton pick-up. Results of local, zero-range DWBA calculations will be given for states up to 8 MeV excitation in 47K and compared to those from a previous experiment1). In addition to the known 2s.,«> ld3/2 and lds/2 Prot *) P. Doll et. al., Nucl. Phys. A263 (1976) 210 72 Session XI Wednesday 12.00 - 12.20 p.m. 72 83. THE PARTIAL FUSION REACTION AND ITS APPLICATION TO HIGH-SPIN SFECTROSCOPY by H. Yamada School of Physics, University of Melbourne, Parkville 3052, Victoria ABSTRACT: A partial fusion reaction (PFR) in heavy-ion collisions is defined as a phenomenon in which energetic light particles are ejected at forward angles, while an associated fusion of the rest of the nuclear mass takes place. The main contribution to the PFR arises from peripheral collisions. The peripheral nature of the PFR was established experiment- ally [1] from Y-ray multiplicity measurements for p, d, and t emission in the 15'lSm[1'fN,pfd,t)xn]157"l59Er reactions. The observed average Y-multiplicities were found to remain constant at 31 for all yrast transitions. This value is larger than is normally found in complete 1 fusion reactions. The deduced average entrance angular momentum was 63 h - near the critical angular momemtum for the 1J|N fusion reaction. This implies the existence of a localized ^-window. These findings are consistent with that expected on the basis of the massive transfer model. Measured mass distributions of the residual nuclei also confirm the presence of a narrow ^-window. Tfie PFR has been utilized in an E - E correlation study for the first time [2]. Initial population of^only high-spin states via this reaction mechanism proves to be of great advantage in high-spin spectroscopy studies. The E - E correlations for the case of 158Er were measured using 12.7cm x 12.7cm Nal detectors in coincidence with p, d, and t emitted in the above PFR. We beieve that the selective high-spin population resulted in the enhanced contrast observed in these correlations. The central valley, which is a signature of collective rotation, was found to persist up to 1.46 MeV - the highest value observed to date. The sensitivity of this method was corroborated by the Monte Carlo simulation method in which the empirical response functions of the Nal detectors were taken into account, while the continuum yrays were simulated using the code GAMBLE. Thus, credence in the physical meaningfullness of the termination found for the central valley is underscored. A possible interpretation of this finding is the loss of colectivity at high spin (in this case estimated at spin 48 ft) in the well deformed nucleus; a spin value consistent with recent theoretical calculations of shape transition using a cranked Nilsson model. REFERENCES: [1] H. Yamada et al_., Phys. Rev. C24 (1981) 2565. [2] H. Yamada et al., Phys. Lett. 128B (1983) 33. 73 Session XII Wednesday 1.00 - 1.20 p.m. 73 84. Fundamental Experiments with Neutrons A.G. Klein, G,I. Opat § W.A. Hamilton School of Physics University of Melbourne Parkville, Victoria 30S2 I We report the result of a recent version of the Fizeau experiment performed with neutrons at the University of Missouri Research Reactor. On theoretical grounds if is predicted that no phase shift is to be expected if a neutron beam traverses a slab moving tangentially to its boundaries. In addition we discuss future proposals for a new experiment in which the coherence structure of a neutron beam will be investigated. if i , • 74 Session XII Wednesday 1.20-1.40 p.m. 74 J 85. THEORETICAL CALCULATION OF THE FORWARD CROSS SECTION I FOR DEUTERON PHOTODISINTEGRATION AT LOW ENERGIES W. Jaus Institut fur Theoretische Physik der Universitat, Zurich, Switzerland and W.S. Woolcock Australian National University, Canberra, Australia Abstract A longstanding discrepancy exists between the experimental results for deuteron photodisintegration in which the proton emerges in the forward direction, at laboratory photon energies up to 120 MeV, and theoretical calculations using the nonrelativistic impulse approximation and standard potentials like the Reid soft core potential. We shall report the results of an extensive new theoretical calculation with the following features. (1) The Paris potential is used as well as the Reid potential to obtain the two-nucleon wavefunctions used in the calculation. (2) The impulse approximation (no mesons exchanged) is calculated within a consistent framework (the quasipotential formalism) and the relativistic corrections to both the charge density and the current density are derived and calculated to order m"2 , where is the nucleon mass. (3) The one-pion exchange contributions to both the charge density and the current density are fully calculated, for diagrams with and without a A(1232) intermediate state, and the effect of these contributions on the forward cross section is calculated. The results of the calculation may be summarized as follows. (1) Short distance effects (exchange of two pions or heavier mesons, short distance behaviour of the wavefunctions) are unimportant. (2) The use of the Paris potential reduces the discrepancy above 60 MeV. (3) Relativistic corrections to the impulse approximation are -'ery large. (4) Individual pieces of the one-pion exchange correction are quite 1; ' large, but the total correction is small. Vv • (5) The discrepancy between theory and experiment persists below 60 MeV, where new experiments are needed. 75 Session XII Wednesday 1.40 - 2.00 p.m. 75 86. HEAVY ION INDUCED FISSION REACTIONS by R.J. Charity Department of Nuclear Physics, Research School of Physical Sciences, Australian National University, Canberra, ACT 2601. Abstract I Fission and evaporation residue excitation functions have been measured for the compound systems 210Po, 200Pb, 188Pt, 178W, 168Yb and 158Dy produced by 19F and 180 induced reactions. Analysis of this data, reveals a sharp discontinuity in the fission yield as a function of compound nuclear angular momentum, at 40 to 50 H, which may be consistent with a rapid onset of non- 1 equilibrium reactions. Angular momentum dependent fission barriers extracted from this work were found to be consistent with recent calculations. if 76 Session XII Wednesday 2.20 - 2.20 p.m. 76 87. TENSOR POLARISATION t2Q IN PION-DEUTERON ELASTIC SCATTERING J. Ulbricht, W. Griiebler, V. Konig, P.A. Schmelzbach, K. Elsener, M. Merdzan and C. Schweizor. •ss Laboratorium fur Kernphysik Eidg. Technische Hochschule, Honggerberg, Zurich, Switzerland. and I A. Chisholm Physics Department, University of Auckland, New Zealand. ABSTRACT There is considerable interest at present in v+ - d scattering for the information that it may be able to give on the possible existence of dibaryon resonances. These resonances are supposed to arise from a six-quark system with non-conventional coloured sub- clusters. The existence of dibaryon resonances has been suggested by, for example, structures in proton-proton cross-section experiments with polarised particles. One might expect ir+ - d elastic scattering observables to be sensitive to the existence of dibaryon resonances in the proton- proton system. Since spin-averaged observables, such as cross- sections, have a low sensitivity to resonance effects for small channel couplings, one expects that experiments measuring the polarisation of the deuteron would give the best opportunity to see resonance effects. The vector polarisation i t^ arises always from the interference of at least two partial waves. The tensor polarisat- ion component t2Q can, however, arise from a single resonant matrix element giving an enhanced sensitivity to resonances. We have therefore developed a polarimeter for measuring the tjQ of the recoiling deuterons in it"1" - d elastic scattering. Features of the polarimeter are its high efficiency and good rejection of back- grounds. We have made measurements at a high intensity pion channel at the Swiss Institute for Nuclear Research. 'ii We have measured angular distributions of t20 at energies between 110 and 150 HeV. The angular distributions have a behaviour that varies rapidly with energy. An excitation curve of t2Q has a distinct peak near 2.14 GeV. 77 Session XII Wednesday 2.20 - 2.40 p.m. 77 88. THE 41K(p,a)38Ar CROSS SECTION AND ITS SIGNIFICANCE FOR NUCLEOSYNTHESIS by M.E. Sevior, L.W. Mitchell, C.I.W. Tingwell, and D.G. Sargood School of Physics, University of Melbourne, Parkville, Victoria 3052, Australia. Abstract The relative strengths of all the decay channels open to states in **2Ca produced by '''ca+nareof special interest in the nucleosynthesis of many neutron rich nuclei. The only channel for which detailed experimental data do not exist is the alpha-particle channel. These data are most readily accessible via the reaction 4^KCp,a)38Ar, measurements of the cross section of which will be reported. The significance of the results for nucleosynthesis will be discussed. 78 Session XIII Wednesday 3.00 - 3.20 p.m. 78 89. DETECTION OF THE W AND Z PARTICLES by "M L.S. Peak. Falkiner Nuclear Department School of Phvsics University of Sydney. NSS.W. 2006 The discovery of the W and Z particles at CERN in 1983 provided a most exciting and spectacular vindication of the Weinberg 5alam model. This model has achieved the unification of the electromagnetic and weak interactions and is perhaps as significant as the work of Maxwel1. This review paper will trace the experimental zteps which led to this achievement and will present some of the data obtained by the various experiments. , 1 f * K Session XIII WednesdaUednesdayv 3.20 - 4.00 p.mD.m. / VK I General Information 91. GENERAL INFORMATION CONFERENCE VENUE Australian National University, Canberra - Research School of Physical Sciences. See map p. 93. Huxley Theatre and adjacent Seminar Room, as detailed in programme. i j DATE Monday 6th, Tuesday 7th and Wednesday 8th February, 1984 PAPERS Timing Green light shows for presentation of paper - Warning lights show when 5 & 2 minutes are remaining - Red light shows when presentation time has expired - Discussion time of 5 minutes is then allowed by the chairman. Slides Authors using 35mm slides in conjunction with their talk are requested to place their slides in the projector magazine during the break preceding the session in which the paper is scheduled. ACCOMMODATION For out of Canberra participants whose nominations have previously beeii accepted, accommodation has been arranged at Burgaiann College, A.N.U. in accordance with previously advised requirements. - See map p. 93. AINSE will make payment to the college management for bed, breakfast and any meal charges, and subsequently recover from participants any costs for which the individual is personally responsible, under the terms of our letter dated 23/11/83 to group leaders. LUNCHES Packed lunches will be available from the theatre foyer at a cost of $2 per person. (Lunch is not available at Burgmann College). EVENING MEALS Evening Meals are available if required, at Burgmann College at a cost of $4.00. Please add your name to the list provided on the kitchen counter when obtaining your meal. The Institute will pay charges directly to the management and recover costs after the conference. Please advise Joan Watson (02)543-3411 if you require an evening meal on Sunday 5th February. 92. CONFERENCE DINNER - MONDAY 6TH FEBRUARY, 1984 Pre-dinner Huxley Theatre Foyer & Seminar Room 5.30 p.m. - 6.00 p.m. Dinner Burgmann College 6.15 p.m. PUBLIC LECTURE - TUESDAY 7TH FEBRUARY, 1984 Huxley Theatre - 8.00 p.m. 'The diseovevy of Artificial Radioactivity' Professor Sir Ernest Titterton To mark the 50th Anniversary of the discovery of artificial radioactivity by Irene and Frederic Joliot-Curie in 1934. TRANSPORT TO AIRPORT Transport to Canberra airport from the Huxley Theatre will be arranged at the conclusion of the conference. Luggage may be stored in the theatre foyer, beneath the stairway. All enquiries concerning the conference arrangements should be directed to - Mrs. Joan Watson, Conference Secretary, A.I.N.S.E., Private Mail Bag, SUTHERLAND. N.S.W. 2232 Phone: (02) 543-3411 or 543-3111 i;. 93. ffci AUSTRALIAN NATIONAL UNIVERSITY I Huxley Theatre (Compute* Centte) LIST OF PARTICIPANTS J 95. LIST OF PARTICIPANTS OVERSEAS VISITORS PAPER NO. Professor E.W. Vogt Triumf, Vancouver , Canada 6R Professor J. Rasmussen University of California, Berkeley, USA 37R Professor A.R. Poletti University of Auckland, N.Z. 3,28 Dr. A. Chisholm University of Auckland, N.Z. 57,77 Dr. G.D. Putt University of Auckland, N.Z. Dr. P.M. Lewis University of Auckland, N.Z. 28 Mr. S. Poletti University of Auckland, N.Z. Mr. M. Savage University of Auckland, N.Z. 28 Dr. CM. Bartle Institute of Nuclear Sciences, N.Z. 14 JAMES COOK UNIVERSITY OF NORTH QUEENSLAND I (Department of Physics) Assoc. Professor R.B. Taylor 15 Dr. I.B. Whittingham 15 Dr. G.C. Hicks 15 Mr. P. Teansomprasong 15 UNIVERSITY OF SYDNEY (School of Physics) Professor C.B.A. McCusker 68R Assoc. Professor L.S. Peak 16,79R Assoc. Professor M.M. Winn 69 Dr. J. Ulrichs Mr. L. Horton Mr. M.H. Omori 16 Mr. N. Wearne 16 AUSTRALIAN ATOMIC ENERGY COMMISSION Dr. J.K. Parry Dr. J.R. Bird Dr. J.W. Boldeman 11,62R Dr. D.W. Lang Dr. R.L. Walsh 11,41 Mr. Duerden Mr. J.P. Fallon C.S.I.R.O. (Mineral Physics) Dr. G.J. Clark Dr. S.H. Sie 8 Mr. C.G. Ryan 8 AUSTRALIAN NATIONAL UNIVERSITY (Department of Nuclear Physics) If Professor J.O. Newton 5,10R Professor Sir Ernest Titterton Dr. T.R. Ophel 12,20,48,49 Dr. P.B. Treacy 45 Dr. G. Dracoulis 18,43,46,67 Dr. D.F. Hebbard 49 Dr. R.H. Spear 40,44 Dr. A. Chatterjee 5 J 96. AUSTRALIAN NATIONAL UNIVERSITY (cont'd) PAPER NO (Department of Nuclear Physics) Dr. P.V. Drumm 12 ,20 ,48 ,49 Dr.. T. Esat 44 Dr. M . Fewell 17 ,44 Dr. L .K. Fifield 12 ,20 ,48 Dr. G .S. Foote 5 Dr. H.J. Hay 45 Dr. D .J. Hinde 5,38 Dr. J .R. Leigh 5 Professor S. Ogaza 5 ,18 Dr. L,• Pender 45 Dr. A,. Stuchbery 47 ,70 I Dr. D., Weisser 12 ,19 ,20 ,48 Dr. C.,L. Woods 12 ,20 ,48 Mr. R..A. Bark 70 Dr. J.,J.M. Bokhorst Mr. A.i Byrne 18 ,46 Mr. R.,J. Charity 5,76 Mr. 6. Gyapong Mr. M. Hotchkis 12 ,20 ,48 Mr. W.J. Vermeer 40 ,44 (Department of Theoretical Physics) Professor K.J. Le Couteur Dr. F. C. Barker 2 ,71 Dr. C. J. Hamer :34R ,36 Dr. B.A. Robson 9 ,22 ,49 Dr. L.J. Tassie Dr. H. H. Wolter 61 Dr. W. S. Woolcock 75 Dr. G.A. Christos 21 Dr. Y. Kondo 9,,22;,49 Dr. R. Smith 9,,22,.49 (Department of Physics) Professor S. Hinds 40,.44 Dr. A.M. Baxter 40,,44 Dr. M. Burnett 40,,44 UNIVERSITY OF MELBOURNE (School of Physics) 1 Professor B.M. Spicer 1R, 58, 59,,72 Professor H.H. Bolotin 8,,70 I Professor B. McKellar 25, 26, 65 Professor G.I. Opat 74 Professor C. Ramm 7 f Dr. K. Amos 27 Dr. G.C. Joshi Dr. D.G. Sargood 4, 23, 50, 78 Dr. G.J.F. Legge 66R Dr. V.C. Officer 58, 72 Dr. G. Shute 58, 59, 72 Dr. M. Thompson 29,53,54,60R,63 Dr. W. Bauhoff 64 Mr. S.F. Collins 58 •J 97. UNIVERSITY OF MELBOURNE (cont'd) PAPER NO (School of Physics - cont'd) Mr. R. Sutton Dr. H. Yamada 51,73 Mr. P. Andrews 58 Mr. Y. Assafiri 54,55 Mr. S.M. Banks 72 Mr. L. Berge 52 Mr. F. Di Marzio 27 Mr. M. Facci 29 Ms. P. Foot Mr. R. Gorman 25 Mr. H. Granek 65 Mr. B. Lay 24 Mr. P. Lewis Mr. L.W. Mitchell 4.23,50.78 Mr. C. Nash Mr. G. O'Keefe 54 Mr. D.A. Orr 53 Mr. R.P. Rassool 53 Mr. M. Sevior 4,23,50,78 Mr. C.I.W. Tingwell 4,23.50.78 Mr. R. Volkas Mr. J.M.R. Wastell 58.59 Mr. R.O. Weber 50 Ms. L. Wood 70 Mr. D. Zubanov 63 UNIVERSITY OF TASMANIA (Department of Physics) Mr. R. Fanner 30 Mr. J. Gordon Mr. R. Zhang UNIVERSITY OF ADELAIDE (Department of Mathematical Physics) Professor C.A. Hurst 31 Dr. L.R. Dodd 13,31 FLINDERS UNIVERSITY OF SOUTH AUSTRALIA (School of Physical Sciences) Dr. I.R. Afnan Dr. R.J. McLeod 56 Mr. B.C. Pearce 35 Mr. C. Roberts 33 Mr. A.G. Williams 32 UNIVERSITY OF WESTERN AUSTRALIA (Department of Physics) Mr. H.M. Ahsan Ms. J.A. Henderson Assoc. Professor B.G. Kenny Dr. M.D. Gould 42 Dr. E.L. Heck Dr. H.A. Slim 39 Mr. A.A.I. Hussain r'ii:i''r*^""-*r^r--r.frr^"--u-?^'.-.Li« 98. DARLING DOWNS INSTITI/TE OF ADVANCED EDUCATION (Department of Physics) PAPER NO. Mr. E. Tiller A.I.N.S.E. Mr. E.A. Palmer Mr. D.D. Cohen Mrs. J. Watson I f. \