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INIS-mf--11126
PROCEEDINGS, VARNA, BULGARIA, MAY 6-8, 1985
INSTITUTE OF NUCLEAR RESEARCH AND NUCLEAR ENERGY BULGARIAN ACADEMY OF SCIENCES FIRST BALKAN CONFERENCE ON ACTIVATION ANALYSIS 1985 The Organizing Committee gratefully acknowledges the financial support of the following institutions: Agricultural Academy State Committee for Science and Technical Progress Committee for Environmental Protection Union of the Scientific Workers in Bulgaria Union of Chemistry and Chemical Industry
PUBLISHED BY SOPIA PRESS Designer K. Krastev PROCEEDINGS
VARNA, BULGARIA, MAY 6-8,1985 Chairmen of the Organizing Committee - Prof. Zh. Zhelev Secretary - in - charge - L.Kinova FOREWORD
, Almost fifty years elapsed from the first publication in the field of activation analysis.During this period activation analysis won a wide recog- nition. Its principal merits: the possibility of simultaneous determination of several elements,the high sensitivity.precision and accuracy of measure- ment, the applicability to different materials,combined with the developement of high resolution semiconductive detectors and multichannel analysers brought it to the state of a preferable analytical method in many' areas of science and technology. In the last few years NAA found a wide application in the Balkan coun- tries with a significant contribution to the technical progress. The common interests in this area are a good premise for collaboration in the. Region. The purpose of the First Balkan Conference on Activation Analysis is to give an opportunity to scientists from this area to exchange information on the state of activation analysis in their countries as well as to create more close contacts.The united efforts of the scientists from Balkan coun- tries will foster the further developement of the activation analysis and, therefore, will enhance the contribution of the atomic energy to peace,health and prosperity in the Region. The Proceeding includes all papers submitted to the Organizing Committee until 1985, March, 30. CONTENTS
REVIEW PAPERS
Neutron Activation Analysis in Bulgaria D. Apostolov Neutron Activation Analysis in Romania . S.Apostolescu Activation Analysis in Greece A. P. Grimanis
METHODS IN ACTIVATION ANALYSIS
Epithermal neutron flux distribution and its impact on ( n, jc ) activation analysis result „ 19 S. Jovanovic, F. Da Corte, A. Simonits, L. Moena, P. Vukotic, R. Zejnilovic, J. Hoste The neutron activation analysis in the study of Langmuir-Blodgett multilayers composition - relation to other methods of investigation 25 J. G. Petrov, I. Kuleff Neutron activation analysis of semiconductor silicon 29 S. Apoetoleacu, A. Pantelica, M. Salagean Determination of some trace elements in biological materials using the short lived isotopes 32 E. Taskaev Se in biological SRM'BI a comparison of results obtained by different neutron activation methods 35
M. Dermelj(A. Gosar, M. Frank o, A. R. Byrne, L. K o s t a, P. Stegnar 14 MeV proton activation for protein analysis in cereals 37 B. Constantineacu, E. Ivanov, D. Plostinaru, A. Popa-Nemoiu, G. Pascovioi Determination of iodine-129 content of the primary coolant of nuclear power reactor 40 I. Kuleff, S. Zotschev, G. Stefanov Neutron activation analysis of some high purity substances 44 M. Salagean, A. Pantelica, C. Dan, E. Apoatol 14 MeV neutron activation analysis for oxygen determination in silicon single-crystals 47 D. TimuB, V. Galatanu, D. Catana, N. Blega, 0. Popescu,A. Bradeanu Instrumental photoactivation analysis of some elements in steel 50 V. Galatanu, D. Timus, D. Catana Application of the INAA to the initial comparison of proectile lead ... 52 D. Dimitrov Determination of Al, Cl, S and V by nondestructive activation analysis 55
B. SmodisfL. Kosta, A. R. Byrne, M. Dermelj Determination of platinum concentration in gold matrix by neutron activation 57 V. Cojocaru, S. Spiridon Impurity determination in BigO, and PbClg by neutron activation analysis and atomic absorption spectrometry 60 S. Aleksandrov, I. K u 1 e f f, R. Dj i n g o v a, S. Arpadjan, E. Taskaev Determination of mercury content in milk powder 63 M. Iovtchev.T. Grigorov, D. Apostolov Simple and fast determination of Rb and Cs in mineralized waters 65 S. Taskaev Gamma - spectrometric system based on personal computer "PRAVETS - 83" 66 K. J a n a k i e v, L. T o m o v, T. Grigorov, M. Vutchkov Computational description of fast neutron activation data 69 M. Avrigeanu, M. Ivascu, V. Avrigeanu Absolute nondestructive quantitative determination of uranium in special nuclear materials 71 T. Dragnev, B. Damyanov, G. Grozev, J. Karamanova Program for the quantitative and qualitative analysis of Ji, - ray spectra 74 V. T e p e 1 e a, E. P u r i c e, R. D a n, G. C a 1 c e v, M. D 0 m n i s a n, V. G a 1 i s, G. Teodosiu, C. Debert, N. Mocanu, M. Nastase
MEDICINE AND BIOLOGY
Investigation of the behaviour of some elements in heart of thymectomised rats ».. 79 L. K i n o v a The feasibility study of in-vivo analysis of bone calcium by activation of hand with 5 Cl 238Pu - Be 81 H. Sevimli Distribution of some elements in human colon mucosa B3 R. J. Draskovic, U. Bo zanic Analysis of human renal calculi by INAA 85 L. Kinova, Iv. Penev, M. de Bruin Determination of sodium in Pharmaceuticals by neutron activation analysis 87 G. D. K a n i a s, N. H. C h o u 1 i s Investigation of distribution of zink, iron and antimony in healthy and pathologically altered liver tissues 90 K. Kostic, S. Stankovic, R. J. Draskovic The influence of some additives to the highly carbohydrate diet on the distribution of Al, Ca, Cl, Mg, Mn and Na in teeth enamel and bones of experimental animals 92 P. Bakyrdachiev, I. Kuleff, E. Djulgerova, M. Iovtschev On the content of sodium,potassium, magnesium,calcium and chlorine in organs of WISTAR rats 93 M»Iovtchev, L. Kinova, T. Grigorov, D. Apostolov, Z. Kemileva
ENVIRONMENT
Instrumental neutron activation analysis in environmental research ( invited lecture ) 99 M.de Bruin RNAA determination of As, Cd and Zn in biological materials 108 E. T a s k a e v, Iv. Fenev, L. Kinova Defining of concentration factors in the biota of the river Sava by the method of nondestructive neutron activation analysis 110 S. L u 1 i c Analysis of some mineral salts by neutron activation method 113 A. Pantelica, M. Salagaan, S. Spiridon, Gh. Spiridon Determination of trace element concentration factors in some marine organisms by neutron activation analysis 115 A. Vertacnik, S. Lulic The concentration of active and inactive strontium in some Danube river samples . ...r • 118 K. Kosutic, S. Lulic Mineral composition of the plant npecies of the Hypericum family 121 L. Marichkova, 0. Kjostarova Trace elements in Turkish tea leaves determined by instrumental neutron activation analysis 124 R. Demiralp Investigations of some regional river systems by INAA and X - ray fluorescence 125 R. J. Draskovic,A.Kukoc, M. Pantelic Neutron activation investigation on the accumulation of some elements in Taraxacum officinale, resulting from environmental pollution 128 I. Kuleff, R. Djingova Determination of some elements in bottom sediments from Varna bay, Bulgaria and Saronikos gulf, Greece 129 D. Apostolov, M, Iovtchev,L. Kinova, F. Nikolov, Iv. Penev.E. Taskaev, T. Grigorov, A. Stojanov, A. P. Grimanis, G. K a n i a a, C. Papadopoulou, M. Vassilaki-Grimani, D. Zafiropoulos Studies of trace elements in marine organisms from Kastela bay in the central Adriatic 132 M. Tuaek-Znidaric, M. Skreblin, J. Pavicic, P. Stegnar, T. Zvonaric Macro - and microelement determination in some species of the family Fumaria I. distributed in Bulgaria 134 L. Harichkova, 0. Kjostarova Application of nuclear analytical techniques to Investigate trace elements content in foodstuffs .. 137 A. G h a r i b
GEOLOGY
Some remarks on NAA in geochemical research ( invited lecture ) , 141 UUGeisler Neutron activation analysis of some zircon samples from the Apuseni montains ( Romania ) 149 M. Salagean, A. Pantelica, V. Znamirovschi, A. Motiu Determination of some REE elements, scandium and cobalt in Bulgarian geostandard GRANITE G-B 152 E. Taskaev, D. Apostolov, H. Schelhorn Rapid uranium analysis by deayed neutron counting of neutron activated samples 154 M. N. Papadopoulos REE geochemistry of the Stara Planina ophiolite association 15? L. D a 1 e v a, I. Haidoutov Potassium determinations in clayey minerals by neutron activation analysis * 160 L. DineBCU, C. Plameda Simultaneous neutron activation determination, of aluminium, magnesium and silicon in rocks 162 I v. P e n e v, I. Kuleff, R. Djingova Multielement neutron activation analysis of silicate rocks using successive short and long sample irradiations «• 1&5 P. Vukotic, S. Jovanovic Determination of trace elements in fly coal ash ( ENO, EOP, ECH refference materials ) 171 M. Salagean, A. Pantelica Uranium content measurements on II - phosphate ores 174 M. Salagean, A. Pantelica, S. Spiridon Determination of uranium and thorium content in rocks toy epithermal neutron activation analysis 175 1. Dinescu, C. Flamada Activation analysis of indium used as tracer in hydrogeology 177 S. P. Stanescu, 0. M. Parcasiu, E. Gaapar, S. Spiridon, V. 11. Nazarov, M. V. Frontasieva Data on the REE, Th and Hf - content in volcanic rocks from central Cuba 180 I. Ioilanov, D. Tchounev The detenu-'nation of the silver content in some ancient coins by using an Am - Be neutron source 183 G. C o a a a, T. P i a t, V. Znamirorschi, L. Daraban, V. Morariu, D. Boros, D. Alicu Monostandard activation analysis of prehistoric copper objects 186
vr • n •* c, c a r u, II. Ivascu, C. Beslitt, D. Di^aerian, D. Fopoviei Archaeometrio investigation of medieval Bulgarian glasses and sgraffito ceramics by neutron activation analysis 189 R. Djingova, I. Kuleff Determination of trace elements in soil 190 M. Salagean, A. Pantelica Investigation of the connection between surface water and underground water from mine CACOVA - IERII, using activable tracers 192 L, Dinescu, V. Domocos, St. Cracium Fast neutron activation analysis of short-lived nuclides in some geological samples 194 S. M. Al-Jobori, et al.
AUTHOR INDSZ 195 REVIEW PAPE RS NEUTRON ACTIVATION ANALYSIS IN BULGARIA
D.Apostolov Institute of Nuclear Research and Nuclear Energy, Sofia
The first attempt for instrumental neutron activation analysis was made by analysis of indium in intermetall alloyB by means of Po-Be source in the Institute of Nuclear Research and Nuclear Energy in Sofia.The develop- ment on INAA as a routine method starts with bringing into use in I960 of the experimental nuclear reactor in Sofia.With the introduction of semi-con- duotive detectors and high quality multichannel analysers the method finds its wide applications in different parts of science and industry.
SYSTEMS AND METHODS OP IRRADIATION
At the present the main source of neutrons is the experimental reactor 2 MW - IRT-2000.For the purposes of INAA the vertical channels are used. 12 2 The neutron flux vary from 1 to 6x10 n/cm sf with Cd ratio for gold of about 4,4.In one of the channels the neutron flux is additionally thermalised with grafite (thermal columne ),In other vertical channel a pneumatic double- tube rabbit system is installed.One of the irradiation positions is equiped with 1mm Cd shield constantly.With the pressure of the working gas ( air ) of 2 bar the transport time in one direction is 2,5 sec. In this way for INAA are available isotopes with the half-life of few seconds and more,when the irradiation iB carried out in pile or epithermal neutron flux, and few hours and more,when the irradiation is carried out in thermal column.Because of lack of special system for uniform irradiation an accuracy of 3% could be reached by use of iron monitors for long irradiatons and copper monitors for use in the rabbit system. At the moment in Bulgaria are working also two neutron generators but the application of 14 MeV neutrons for INAA is still quite limited. Radiochemical methods ( RNAA ) are used at the present only for investi- gation purposes.
APPLICATIONS
Geology and pedology: The application of INAA in this area is most developed.Investigated are the composition of the fields,of strongly minera- lised underground waters and the possibility to extract from them some use- ful products.Some investigations are carried out on rocks and sediments for the purposes of geology.The study of soils is conducted for the improvement of agriculture. Medicine and biology; Model experiments are performed on laboratory animals for the establishment of a connection between the content of essential macro- and microelements in different organs and the development of some processes in disease.Studied is also on model experiment the effect of plati- num preparations on the treatment of cancer.Investigated is the elemental content of human tissuestplants and other. Environment and pollution: Conducted are tracer experiments for the study of the effect of point pollution emmiters ( factory chimney for instance). Examined are the possibilities to use some plants and animals as a monitors of air pollution.Studied is the influence of different pollutants on the distribution of toxic elements in human organs,sea water organisms and others. Archeology;An extensive investigation is carried out of ancient glasses and ceramics for archaeometry purposes.An attempt is made for analogous investigation of ancient flint and obsidian objects. Technology: By means of INAA is analysed the wearing of some machine parts,controlled are some processes in metallurgy as well as the final technological products.Investigated are the possibilities for regeneration of some valuable apended catalysts from chemical industry. Meteorology and hydrology: Experiments are conducted with activable tracers for the study of local atmospheric phenomena and the movement of the underground waters. Criminology; Developed are methods based on INAA for analysis of car paints and traces of shooting for the investigating purposes.
Qualitatively NAA in Bulgaria maintaims a good level.The interlabora- tory intercomparison runs,organised by IAEA and other institutions offer a perfect opportunity for each group to check the quality of their results. Quantitatively the further development of NAA and its applications is limited by the possibilities of the reactor.In the near future a reconstruc- tion and modernisation of the reactor is being planned,which will extend the possibilities for the analysis.Building of accelerator and more power- ful neutron generator which is due in the near future in Bulgaria will also contribute to the use of neutron activation analysis. HBUTRON AOTIVATION ANALISBS IN ROMANIA SSelian Apostolesou Institute for Physios and Nuolear Engineering Bucharest IIG-6, Romania The history of activation analyses in Romania, starts way back in 1957 whan a 2000 Iff 7VR-S Nuoltiar Reactor, and in 1958 when a U-200 Cyclotron have bean pat into function. The Institute for Atonic Physics has been developing its researoh activity around these two basic nuclear facilities. Soon after that a 30 MeV Betatron entered into operation and during the following years several 14 HeV neutron generators have been built or installed in various sites over the country* A king size High Voltage tandem Van de'Graaff accele- rator Joined later the nuclear facilities at the beginning of seventies. At about the same tine, the State Oommettee for nuclear Energy has orga- nized nationwide Courses for Radioisotope Applications, training specialists in various fields as geology, biology, medloine, engineering, agriculture and so on, in the peaceful uses of nuolear energy* leaching at this courses were the research workers and the university staff in this field. In this way the courses have become a kind of national forum debating the appropriate ways for a wide application of nuclear methods in technology, agrioulture and the other related fields of science and eoonomy* Soon has been found out that the most effective lmpaot of the nuolear methods in the related fields, beside the ove- rall problem of nuolear energy consists in the nuolear analyses and X-ray flu- orescence methods* THKRH&L NEUTRON ACTIVATION ANALYSIS (THAI or INAA) Historically the first thermal neutron activation analyses carried out at the romanian nuolear reactor, were in late fifties dealing with the analysis of the purity of silicon as semioonduoting material* Since then, traoe elements determinations la silioon has been a oonstant task for our researchers in va- rious groups* She whole romanian industry of semioonduoting devices, benefits greatly now of slstematio and routine purity analyses, as well as nuolear do- ping by irradiation of silioon llngots in the aotlve core of our reactor. In the early sixties, a pneumatio rabbit system has been set up into one of the horizontal channels of the reactor, enabling measurements on short lived isotopes* The transit time of a few seoonds has allowed determinations on iso- topes whose lifetimes range as short as tens of seconds* This rabbit system has been in operation along a period of more than twenty years and is still in servioe. being used by all the research groups dealing with thermal neutron aotivation analysis on short lived isotopes* ThiB rabbit system is also used for delayed neutrons measurements on the uranium content in ores* Taking into account the faot that lately, the demands for such analyses have greatly Increased beyond the oapaolty of the present pneumatio system, a new and Improved rabbit is under construction and is to be set up ontoanother horizontal channel of the reactor* This new air rabbit will have a six position revolving ohargeable magazine and an intricate system of awltohos, to direct the sample in various positions, aooording to the irradia- tion programme* The whole system is designed to be before long controlled by the computer* As one oan see in the proceedings of this conference, a great deal of re- search and routine work is being carried on at this moment by an important number of working teams* As an example of some activities in thermal neutron aotivation analyses, the main domains will be be outlined as followsi QBOLOGT AND MIKIKG Beveral groups in the Institute for PhysiOB and Nuolear Engineering, in the Institute for Radiation Equipment, in the Institute for Geology and Geo- physics and the Institute for Rare Metals have been and are doing r«searoh and routine work for the determination of useful minerals in ores, like Iron, mo- libdenum, ziroonium, platinlo metals, uranium and thorium and all other metals as well BB nonmetallferous minerals like kaolins and refractory days* In the followings, a few works of this kind are mentioned! - Determination of gold and platlnio elements in Apuseni Carpathians ores. - Analysis of some mineral salts by INAA. - Uranium oontents taeaaurements on U-phosphate ores. - Neutron aotivation analysis of some zlroon samples from the Apuseni Carpathians. - Determination of alumina and silica oontents in kaolins and refractory olays by a oomblned method of TNAA and PNAA. - Hare-earths determinations in geological samples. PROCESSING OF MATERIALS The ras«arohsra of the Institute for Physios and Nuclear Engineering have oarried out important work in co-operation with the soiantists and technolo- gists of the industry in the study and production of high purity and/or special materials. Units like the Enterprise for Eleotronio Components and Semiconduc- tors, the Institute for Besearoh in Slaotronio Components, the Institute for Hetalurgioal Hesaaroh, and many others, osdar routine analyses, or co-operate in research programmes for high purity studios, in solving aoute technological problems* Here are some examples of works performed in these oo-operationst - Neutron aotivation analysis of semiconductor silicon. - Neutron aotivatio n analysis of high purity OaFo, GeO?, BioOp* and - P.p.aCN%)2lIoOi|.. leve4l %(oobal> t content in special steels. - Glass powder purity studios by INAA. - INAA on high purity quartz* - INAA on high purity graphite. ENVIRONMENT AND BIOLOGI Studies have been oarried out in co-operation with institutes for healths, for biology and for food processing* Examples of works in this fields are as follows! - Analysis of algae and marine sediments on the ronanian coastline of the Black Sea* - Study on the possibility of using algae as detectors for environmental pollution. - Analysis of human hair content. - Determination of oligoelements in human serum. AROEBOLOGI A great deal of the analysis work is being oarried on in co-operation and for the benefit of the history museums all over the country. Here are a few of. the oharaotoriatio works of this kinds - INAA of prehistorioal copper objects. - A correlation between the XRF and NAA methods in numismatic studies. - NAA studies on middle ago pottery. - NAA characterisation of bizantyne glass wares. INTBROOMPARISONS One of the interoomparisons, our nuclear analysts have taken part in, were those organised by I ABA'a Analityoal Quality Oontrol Servioe* Our most re- cant participation is oonnected with the determination of 32 elements at the p.p.m. level in 8OIL-7. a referenoe material prepared of a soil oelleoted near Xbonsoe in Upper AuBtria. We are glad to report good results in comparing our determinations with the oertified values of the AQO Servioe* In the past years the same kind of interoomparison participations have to be mentioned on rye flour, human hair, and mussel tissue materials* The same group of our most outstanding analysts have taken part in an in- teroomparison organised by the Institute of Radioeoology and Applied Nuclear Techniques of Kosice - Czechoslovakia, on referenoe materials realized from fly coal ashes* An interoomparison among the balkan countries would greatly increase the oonneotions and the co-operation of our laboratories* BPITHBR1IAL NEUTRON AOTIVATION ANALYSIS (BNAA) The determination of uranium and thorium in ores with high Th/U ratios or high rare earth oontents speoial problems arise in TNAA methods. The problem has been solved using epithermal neutrons for aotivation. Participation in a IAEA interaomparison on 8-14-, 8-15 and 8-16 reforenoe materials, has shown how good this method can be in suoh difficult matrioes. FAST NEUTRON AOTIVATION ANALYSES (PNAA) Three low energy accelerators are used as 14-*1 MeV neutron souroes, one of them entirely specialised on PNAA. This one, installed in the Institute for the Technology of Radiation Equipment is provided with speoial equipment for oxygen and low mass elements determinations. This equipment consists in an air rabbit having two parallel ways, one for the unknown sample and one for the standard, with simultaneous irradiation and also simultaneous measurement at two large Nal(Tl) measuring hea: ds, appropriately equilibrated* This installation carries on routine measurements on the determination of oxygen content In steels and aluminium. Also theoretical nuclear model calculations are being used to extent the neutron data basis available for applications.This computational method is based on the statistical model (Hauser - Feshbach STAPRE code) and the pre- equilibrium decay geometry dependent model* Thus en accurate theoretical des- cription of the fast neutron induced reactions is an useful alternate way to support FNAA. OHARGBD PARTICLES ACTIVATION ANALYSES (OFAA) The posibility of bringing out into the air of a proton beam at the cy- clotron, raised the possibility to install a gravitational sample changer at the end of a beam line and to perform mechanized analyses for protein deter- minations in grains. Protons of 14 UeV are being used and a (p,n) reaction on nitrogen helps to make the quantitative analysis of this element, that is closely conneoted to the protein content in grains* The installation, already in routine operations, analyses thousands of samples yearly, each sample mea- ning as container of about 4 cubic centimeters of wheat, barley, corn, sor^um or whatever other oereal* I include in the domain of charged particles activation analysis, a very interesting method of determination of the profiles of hydrogen content in the surface layers of solids, that has been put into work at the tandem Van de'Graaff accelerator. It uses the isolated narrow resonances that usually oocur in heavy ion induced reaotions* For instance, the reaotion H-S5 + H-l •• 0-12 + He-4 + gamma (4.43 MtV) has a oroas seotiot that is outside the resonanoe three orders of magnitude lower than on the peak. By bombarding the sample with N-15 ions of energy greater than the resonanoe (6*385 MeV) and detecting the resulting 4.4? MeV gamma rays by the help of a large volume Nal(Tl) detector, the distribution in depth of the hydrogen concentration is soanned, by gradually increasing the incident heavy ions energy* Interesting applications in microelectronics, spe- cial glasses industry, archaeology, silicon thin layers production, steal al- loys and superoonduoting •at«rials, have been found oat and co-operation with those fields are In prooess of being established. Aa tao Collective for nuclear Analyses has been organised in the Insti- tutt for Physios and Nuclear Engineering starting with the year 19B0, on* hopes that before long all the activities conneoted to nuclear analyse* of all kinds, aotivation included, to be batter co-ordinated and put on a more professional basis* ACTIVATION ANALYSIS IN GREECE A.P. Grimanis Radioanalytical Laboratory, Nuclear Research Center "Demokritos" 153 10 Aghia Paraskevi Attikis Athens, Greece
ABSTRACT Today Activation Analysis is widely applied to the investigation of medical, environmental, industrial, geological and archaeological problems. In this /eview the development of activation analysis methods as well as applications of these methods in medicine, environment, geology, and archaeology are described, mainly based on work done by the author's group in the Nuclear Research Center "Demokritos" of Greece. INTRODUCTION In the last 35 years there has been a tremendous growth of research, deve- lopment and applications of neutron activation analysis (NAA) which resulted in a dramatic increase of the relevant literature, showing an exponential growth from 13 papers in 1949 to over 700 in 1971 (1). This represents a doubling time of about three and one half years. From 1971 up to date NAA reached maturity. The annual accretion of papers in the literature kept an exponential growth pattern at a more reduced rate, more or less equal to that of analytical chemistry (Z). In 1968 and 1969 two new scientific journals, the Radioanalytical Chemistry and the Radioanalytical Letters were circulated to cover the continuous growth of publica- tions related to NAA. The increasing international interest for NAA is evident from the number of papers presented at International Conferences of Modern Trends in Activation Ana- lysis (MTAA). In 1961 during the first MTAA Conference about 1/4 of the presented papers were from 6 only countries other than USA (3) while during the 5th and 6th MTAA Conferences in 1976 and 1981 more than 3/4 of the presented papers were from more than 25 countries other than USA. Several factors contributed to the increasing international interest for NAA some of which are: the establishment of research nuclear reactors in many coun- tries of the world. The use of other nuclear projectiles (charged particles - photons) to the arsenal of activation analysis. The development of radiochemical separation techniques, which, combined with NAA, increased the sensitivity of NAA for some elements to quantities below 10~9 grams. However the main factors which contributed most for the international recognition of NAA were the development of multichannel analyzers (4) and Ge(Li) detectors (5) for v-ray counting and the possibility of v-ray spectra processing by computer techniques. All these increased the number of trace elements which can be determined by Instrumental NAA, reduced the time of analysis and greatly extended the scope of the method. In many cases NAA can be applied successfully as an Instrumental non-destructive multielement analysis method, based upon multi-channel gamma-ray spectrometry of the neutron activated sample. Today NAA is widely applied to the investigation of biomedical, environmental industrial, geological and archaeological problems. Due to its great sensitivity precision and accuracy it is considered as an ideal method for the determination of a large number of minor and trace elements in several materials. In this paper a review of research and development on NAA as well as examples of applications of this method in medicine, environment, geology and archaeology is presented, taken from work carried out over the last 21 years at the Radioana- lytical Laboratory of the Department of Chemistry in the Greek Nuclear Research Center "Demokritos". Charged particle activation analysis and delayed neutron counting methods are also mentioned. DEVELOPMENT OF NAA METHODS AT THE RADIOANALYTICAL LABORATORY In the last 21 years improved and/or faster radiochemical NAA methods have been developed at our Laboratory for the determination of Au(6), Ni(7), Cl(8), As(11), Cu(14), UC15), V(30), Cr(45), Eu(52), Hg(87) and Mo(88) in several materials as well as for the simultaneous determination of Br and 1(9), Mg, Sr and Ni(12), As and Cu(16), As, Sb and Hg(17), Mn, Sr and Ba(19), Cd and Zn(28), Se and As(28), Mo and Cr(28) in biological materials. Instrumental NAA methods have also bn developed for the determination of Ag, Cl and Na in lake waters (6), Al, Ca, Mg and V in wines (100) seven trace elements in biological materials (28), 17 trace elements in sediments (46) and 20 minor and trace elements in ceramics (47) . We have also developed a coprehensive computer program for routine activation analysis using Ge(Li) detectors (36). APPLICATIONS OF NAA IN MEDICAL RESEARCH In 1971 a review article was written on medical applications of NAA (23) to inform MDs in Greece about the availability of NAA methods in medical research. Cystic Fibrosis is a frequent chronic disease of childhood. Its frequency is 1 in 2000 live births. Early diagnosis followed by the appropriate therapeutic program can help a number of children born with this disease to survive to adult age. The sweat test is an accurate procedure most widely used for the detection of CF. This test however has its limitations. The time, expense and necessity for the patient to visit the laboratory limit the number of people who can be tested. In addition the sweat test cannot easily be performed in newborns, dehydrated an' malnourished infants. Kopito and Scwachman (111) first found increased concentrations of sodium in the nail clippings of patients with Cystic Fibrosis (CF). Although their results were very valuable, the method they used was destructive of the sample, time- consuming and unacceptable for large scale applications. Nevertheless their find- ings prompted several investigators to apply Instrumental NAA of sodium in nail clippings for the diagnosis of C.F. Some of the advantages of INAA to nails as a tool for the detection of C.F. are listed below: a) Small samples (1 mg) are re- quired, b) Simultaneous analysis of many samples per day is possible (over 100), c) Samples are not destroyed. On the other hand nails are very convenient material; they can be clipped by anyone, anywhere and no special storage precautions are necessary. However, there is a problem. Since sodium is abundant in nature, conta- mination is freq'uent. Thus, cleaning the nails constitutes a major experimental difficulty. The problem is to remove the surface "contamination" sodium without affecting "intrinsic" sodium.
In the past we have applied INAA for the study of C.F. (24-26,31). We have developed an improved washing procedure for the removal of external sodium contami- nation from nail clippings which combined with instrumental NAA increased the dia- gnostic accuracy of the method from ^75% to >\.90t (25,26). We have developed a simple counting method of sodium-24 in irradiated nail clippings which makes pos- sible the use of inexpensive counting equipment for INAA of sodium in nails. We have successfully applied INAA for the determination of Na in fingernails of 80 patients with C.F. and 2531 controls. The nail sodium ratio of patients to children was 3 to 1 in three pediatric groups examined (newborns, infants, children). We have made a systematic study of 11 more trace elements (Al, As, Br, Ca, Cl, Co, Cu, Mg, Mn, K and Zn) in fingernails of patients with C.F. and controls using NAA. Bromine and chlorine concentrations in nails of C.F. patients of all age groups were found to be 2 to 5 times higher than those of healthy children. Increased potassium and copper concentrations were found only in the nails of in- fants and children. No significant differences were found for the rest of the ele- ments. Increased bromine concentrations were first reported by our group (24). Be- side Na and Cl values, Br in nail clippings from patients with C.F. can be used as supplementary indicator for C.F. Concentrations of Br, Cl and Na determined by INAA at our Lab. in the sweat of C.F. patients were found to be 2.5, 4.0 and 6.0 times higher respectively than those of controls. This research work was partially supported by the IAEA for 3 years (Research Contracts 689/RB/1969, 689/R1/1970, 689/R2/1971). This work was done in collaboration with the First Pediatric Clinic of Athens University. Changes of metabolism happen in women's organism during gestation which are probably necessary for the development of the embryo. The concentrations of Zn, Co, Cu, Se, As, Au, Br and Rb have been determined by NAA in maternal and umbilical cord blood sera as well as in healthy non-pregnant women who served as controls (35,39,44,56). The concentrations of Zn and Co were significantly lower, those of Cu and Au significantly higher while levels of As, Se, Br and Rb were similar in sera of pregnant as compared to sera of non-pregnant women. The mean value of Zn in the umbilical cord sera was about two times higher and that of As 1.7 times higher'than those in mothers. Toxic levels of As were not found in the studied cases.INAA has been applied for thu determination of Co, Rb, Se and Zn in maternal and umbilical cord serum and amnioiic fluid of women with normal pregnancy and prolonged pregnancy (89,90). Significantly lower levels of Co, Se and Zn were found in maternal blood serum and cord serum of women with prolonged pregnancy as compared 10
with those in sera of mothers with normal pregnancy. Zn concentrations weTe also found significantly lower in amniotic fluid of women with prolonged pregnancy.
Six trace elements (Zn, Co, Se , Rb, Br and Au) were also determined in pla- cental and liver tissue samples at birth (53). The mean concentration of the essential trace elements (Zn, Co, Se) were significantly higher in liver than in placenta, whereas the non-essential trace elements (Rb, Br, Au) were found in significantly higher concentrations in placental than in liveT tissue.
The principal food of infants during the first months of their life is human milk or cow's milk and commercial infant foods. NAA has been applied for the determination of seven trace elements (Co, Cr, Cu, Se, Zn, Rb and As) in colostrum, transitional and mature human milk as well as in powdered cow's milk and commercial infants foods in order to find out whether non-breast-fed infants received the same or different amounts of- these trace elements as breast-fed ones. Results have been reported (61). Among them it was found that average concentration of Cu in human milk is about 9 times higher than that of cow's milk.
These works were done in collaboration with the Second Pediatric Clinic of the University of Athens with the exception of the trace element studies in blood sera and amniotic fluid of women with normal and prolonged pregnancies which were performed with the collaboration of the First Clinic of Obstetrics and Gynecology of the University of Athens.
The distribution pattern of Zn, Co, Se, Fe, Cs and Sb has been found by INAA in three parts of myomatus uterus: myoma, endometrium and myometrium. The content of these elements was also determined in submucous, intTamural and subserous myoma (41,62). The variation of the content of Zn, Co and Se in myoma and myome- trium was found to be very significant statistically compared with the variation of these elements in endometrium. The concentration of the six trace elements determined in myoma, myometrium and endometrium has been correlated with age. This work was done in collaboration with the department of Pathology of the University of Athens.
The distribution of three essential trace elements (Co, Se and Zn) in the eyes of premature and normal newborn babies has been studied (40). This work was done in collaboration with the Second Pediatric Clinic and the First Clinic of Obstetrics and Gynecology of the University of Athens.
Trace elements have been determined in the lens, nail and serum of patients with cataract (67,78). The distribution pattern of Ag, Co, Cr, Cs, Fe, Rb, Sb, Sc, Se and Zn in the human cataractous lenses has been studied using INAA. Dif- ferences of concentrations of these trace elements were found in the cataractous lens regarding the concentrations of the same elements in the normal lens (91,92). These works were done in collaboration with the Eye Clinics of the University of Athens.
Active constituents of medicinal plants are products of plant metabolism which is influenced from the variation of the concentration of trace elements. Twenty seven trace elements have been determined in the different parts of the medical plant Helleborus cyclophyllus Boiss and in the soil in which the plant had grown (64,68). The attributed diuretic action in potassium content in some medi- cinal plants has been studied in correlation with the daily requirement for this element in man (69). Recently simple and rapid NAA methods have been developed and used for the direct and indirect determination of active ingredients in drugs (70,96,103,106) and cosmetics (102,105). These works were done in collaboration with the Department of Pharmaceutical Technology of the University of Athens.
Our Laboratory in collaboration with the Department of Pathology of the Uni- versity of Athens was participating under a research agreement at a WHO/IAEA Joint Research Program for the study of trace elements in cardiovasc ' ir diseases (110).
NAA METHODS IN ENVIRONMENTAL RESEARCH
In the last 21 years in our Laboratory NAA methods have been developed and applied to trace elements research in the environment.
In environmental studies we have determined: seventeen trace elements (Ag, As, Au, Ba, Br, Cl, Cu, I, Mg, Mn, K, Na, Ni, Re, Sr, V and Zn) in surface and bottom waters from 11 most important lakes of Greece (6,12), the arsenic uptake in grapes and plant tissues (20,21) and the uptake of Cu, Mn and Zn in needles of seedlings of Pinus grown under a wide spectrum of soil conditions (18). Bromine in soils polluted with bromine pesticides and in the same soils after treatment n with water (34). Several trace elements in drinking water of the Athens area, in river waters and in water pipes (113). Eleven trace elements (Al, As, Br, Ca, Cl. Cu, K, Mg, Mn, Na and V) in experimental and commercial red and white wines from different wine production areas of Greece (16, 81, 100). Certain inorganic nutrients in natural and artificial food of Dacus oleae larvae (60). Nine trace elements (Ag, Co, Cr, Cs, Sb, Sc, Se, V and Zn) in three edible mollusk species (100). A study of trace elements in greek lignites by INAA has been started (113) in collaboration with the Institute of Geological and Mining Research. However most of the trace element environmental research work done in our Laboratory has been concerned with the marine environment. In marine pollution studies we have determined: Br, Cu, I, V and Zn in Pura microcosmus (13). Ten trace elements in the whole body and in ten different parts of the fish Pagellus erythrinus (29), 12 trace elements (Ag, As, Ba, Co, Cr, Cs, Fe, Hg, Mn, Sb.Sr arid" W in Cynthia claudicans (30). Toxic trace elements and elements of radioecologi- cal importance in mollusk species (27,42) in echinoderm species (43,66) and tuni- cate species (49) from Saronikos Gulf, Greece. It was found that certain of these marine organisms may be characterized as radioactive and industrial pollution indicators. In NAA of As and Hg in Pagellus erythrinus (33) and of As, Cd, Co, Cu, Fe, Mg, Rb, Sb, Se and Zn in Sargus annularis (54), arsenic concentrations in the flesh of these two fish species were found to be two times higher in samples from polluted areas as compared with samples from the unpolluted areas of the island of Rhodes and Petalion Gulf. Within the framework UNEP MED POLL II Project, a systematic pollution moni- toring of 14 trace elements (Ag, As, Cd, Co, Cr, Cs, Cu, Fe, Mg, Rb, Sb, Se, V and Zn) in Mullus barbatus and Parapenaeus longirostris (58,73,74) has shown increased concentrations of As in the flesh of Mullus barbatus from northern Saronikos Gulf when compared with specimens from other gulfs of Greece. All higher concentrations of arsenic found in fish species of Saronikos gulf are within the "natural back- ground" levels reported for edible fish by other investigators. No significant differences for the rest of the trace elements were found in the flesh of these marine organisms studied in Northern Saronikos Gulf as compared with the same orga- nisms from other gulfs. It seems that these benthic organisms do not reflect the very high trace element concentrations found in seawaters and sediments of the Keratsini bay in the northern Saronikos Gulf.
A study of trace elements (Ag, As, Au, Ce, Co, Cr, Cs, Eu, Fe, Hg, Hf, La, Lu, Rb, Sb, Sc, Sm, Yb, Zn) as an index to pollution in sea sediments (32,37,46,63) from the northern Saronikos Gulf has been made by INAA. It was found that the discharge of industrial and domestic wastes in the Keratsini and Elefsis bays of the upper Saronikos Gulf has led to elevated concentrations of all toxic and other trace elements determined over at least 100 km2 of seafloor. The 0.5N HC1 extraction method (112) of the silt-clay fraction of sediments was used and was successful for the distinction between anthropogenic and residual concentrations of As and Zn in the sediments (95). Increased concentrations of As, Co, Cs, Cu, Fe, Mg, Rb, Sb, Sc and Zn have been found in seawater samples collected near the main sewage outfall of Keratsini Bay and to a much lesser degree from Faliron Bay (97,113). The affected area how- ever is not very extended since concentration of trace elements fall to natural background levels within 5 km2 from the outfall. Six trace elements (As, Co, Cs, Fe, Se and Zn) have been determined by INAA in otoliths of the pelagic fish Scomber japonicus colias from the Aegean Sea (65, 71). It has been found that in general the content of the studied elements in otoliths decreases with increasing age of the fish. Several trace elements have been also determined by NAA methods in skeletal formation of fish species (48) in plankton (50,85) in marine organisms and sediments of the Aegean Sea (51,59,72,75, 76,83,84,86,93,94,99). Recently the distribution of arsenic in water columns, water particulates and sediment cores from Northern Saronikos Gulf has been studied (109). INAA has been applied for the determination of nine trace elements (Ag, Co, Cr, Cs, Fe, Rb, Sc, Se and Zn) in the medusae Aurelia aurita and Pelagia noctiluca (104) and in muscle, liver and heart of Boops boops and TracTiurus mediterraneus (108). Within the framework of the scientific collaboration between the Activation Analysis Group of the Institute of Nuclear Research and Nuclear Energy (INRNE) of Sofia, Bulgaria and the Radioanalytical Laboratory of the Nuclear Research Center Demokritos, nine trace elements (As, Co, Cr, Cu, Mg, Rb, Se, V and Zn) were deter* mined by NAA in the flesh and liver of the edible fish Gobius niger caught from Varna Bay, Bulgaria and Saronikos and Petalion Gulfs, Greece. No dangerous concentration 12
- for the human health - of the nine trace elements under investigation were found in all samples of the Gobius niger, Our laboratory has particinated at the UNEP MED TOM. II and UNEP MED POLL VIII P.ojects for the protection of the Mediterranean. The partial financial support of our laboratory for these projects by UNEP/FAO as well as for the Research Program "Fates and Pathways of trace elements in the Saronikos Gulf" by the European Econo- mic Communities is gratefully acknowledged. NAA IN ARCHAEOLOGY INAA is widely applied to the investigation of archaeological problems. Ele- mental composition, of an object of art besides form, shape and decorative style may give a supplementary indication of the origin of the object. The museum curator will often permit the removal of a specimen from an object for analysis if the amount taken is such a tiny fleck (a few ings) that its absence is virtually unde- tectable. In such small quantities of a pottery sample for example more than 20 trace elements can be determined by INAA. At our laboratory we have applied INAA methods to the investigation of prove- nance problems of ancient books, ceramics, obsidians, flints, limestones and marbles. We have examined 50 paper samples from old Venetian books (38) in order to correlate the concentrations of trace elements and the age of the books. INAA has been applied for the determination of 20 minor and trace elements (As, Ce, Co, Cr, Cs, Cu, Fe, Hf, La, Cu, Na, Rb, Sb, Sc, Sm, Ta, Tb, Th, Yb and *Zn) in two groups of potsherds (47) which have been excavated at two different sites of Greece, the island of Thasos (Group A) and Delos (Group B). A good agreement for all the elements examined between the pottery specimens of Groups A and B was found. This matching in chemical composition found by INAA between the two groups A and B provides strong support for the archaeologistrs hypothesis that the two groups belong to the same major group of "melian" pottery. INAA and X-ray techni- ques have been applied for the determination of 24 major, minor and trace elements in four different groups of vases (55,77). Protocorinthian, Thapsos Class, Late Geometric Corinthian and Aigion Crater). The matching in chemical composition of the four groups of vases found, strongly suggests the same origin for all of them. X-ray and NAA and mineralogical examination have been applied to obsidian samples found in the excavation of Kitsos cave at Sounion (82). The trace element concentrations found in Kitsos obsidian match with those of Melos origin found in previous works. Current research at our Laboratory on Archaeometry deals with provenance studies of ancient pottery from the islands of Naxos and Thera, and Peloponese, as well as ancient marble from different sites of Greece. Within the framework of collaboration between the AA group of the (INRNE) of Sofia, Bulgaria and the Radioanalytical Lab of NRC Demokritos, Greece a common project started on the development and application of NAA methods to the study of trace elements in flint samples from flint quarries and ores from Bulgaria and Greece as well as in archaeological flint objects found in museums of honey or white honey colour. CHARGED PARTICLES ACTIVATION ANALYSIS A rather extended charged particle activation analysis program is carried out for the last 10 years at the Tandem van der Graaff Accelerator Laboratory of the NRC Demokritos, by another group. It includes Particle Induced X-Ray Emission (PIXE) analysis, Particle Induced Prompt Gamma-ray Emission (PIGE), other nuclear reactions and proton activation analysis. It should be noted that the first exter- nal beam PIXE technique was established by this group (114,115). Several papers (116-121) have been reported with applications in the field of biological, environmental sciences in archaeometry etc. DELAYED FISSION NEUTRON COUNTING A special neutron activation method, the delayed fission neutron counting method is used for the analysis of fissionable elements, as U.Th.Pu, in samples of the whole nuclear fuel cycle including geological, enriched and nuclear safeguards samples. At NRC Demokritos so far the method has been applied extensively to geo- logical samples for uranium exploration (122). 13
In conclusion, I would like to add that NAA is another peaceful application of atomic energy. In biomedical and environmental research it may contribute to a higher standard of living. It can also be advantageously used to solve indus- trial, geological and archaeological problems. However, a close collaboration of clinicians, biochemists, physiologists, environmentalists, ecologists, oceanogra- phers, industrialists, geologists and archaeologists with activation analysis spe- cialists is necessary.
REFERENCES
1. G.J. LUTZ, R.J. BORENI, R.S. MADDOCK, J. WING, Activation Analysis: A biblio- graphy through 1971. Nat. Bur. Stand. (USA) Tech. Note 467 Aug. 1972. 2. F. GIRARDI. J. Radioanal. Chem., 69 (1982) 15. 3. W.S. LYON, J. Radioanal. Chem., 69 (1982) 107. 4. W.S.CROUTAMEL.F.ADAMS.R.DAMS, Applied Gamma-Ray Spectroscopy, Pergamon Press, New York, 1970. 5. F. GIRARDI, G. GUZZI in "Advances in Activation Analysis", vol. 1. J.M.A. LENIHAN, S.J. THOMSON (eds) Academic Press, London and New York, 1972, p.137. 6. A.P. GRIMANIS, G. PANTAZIS, C. PAPADOPOULOS, N. TSANOS, Proc. 3rd U.N. Conf. Peaceful Uses Atom. Energy, Geneva 15 (1964) 412. Part of this work was also published at the Journal Isotopes and Radiation Technology 2 (1965) 345. 7. A.G. SOULIOTIS, Anal. Chem. 36 (1964) 1385. 8. A.G. SOULIOTIS, A.P. GRIMANIS, N.A. TSANOS, Analyst 90 (1965) 499. 9. E.P. BELKAS, A.G. SOULIOTIS. Ibid 91 (1966) 199. 10. A.G. SOULIOTIS, A.P. GRIMANIS, N.A. TSANOS, Talanta 13 (1966) 158. 11. A.P. GRIMANIS, A.G. SOULIOTIS, Analyst 92 (1967) 549. 12. A.G. SOULIOTIS, E.P. BELKAS, A.P. GRIMANIS, Ibid 92 (1967) 300. 13. C. PAPADOPOULOU, C.T. CAZIANIS, A.P. GRIMANIS, Proc. Nuclear Activation Techni- ques in the Life Sciences, International Atomic Energy Agency, Vienna (1967) p. 365. 14. A.P. GRIMANIS, Talanta 15 (1968) 279. 15. D.C. PERRICOS, E.P. BEI.KAS, Ibid 16 (1969) 745. 16. A.P. GRIMANIS, Nat. Bur. Stand. (U.S.) Spec. Publication 312, Vol.1 (1969) p. 197. 17. I. HADZISTELIOS, A.P. GRIMANIS, Nat. Bur. Stand. (U.S.) Spec. Publication 312 Vol. (1969) p. 184. 18. N. YASSOGLOU, S. VRACHAMIS, C. NOBELI, A. GRIMANIS, N. TSANOS, C. APOSTOLAKIS, E. PAPANICOLAOU, Final Report USDA PL 480. Research Project No.E11-F.S.2 Athens (1969). 19. I. HADZISTELIOS, C. PAPADOPOULOU, Talanta 16 (1969) 337. 20. A.P. GRIMANIS, C. PAPADOPOULOU, B. DARIS, I. KELPERIS, Les Progress Agricole et Veticole An. 87 (1970) 10, 87 (1970) 38 (in French). 21. B.T. DARIS, C. PAPADOPOULOU. I. KELPERIS. A.P. GRIMANIS. Proc. of the 10th British Wheat Control Conference at Brighton. Enqland, vol. 1.(1970) p. 429. 22. A.P. GRIMANIS, M. GRIMANI, Proc. of the 4th Panhellenic Chem. Congr. in Athens (1970) p. 123 (in Greek). 23. A.P. GRIMANIS, latriki 20 (1971) 85 (in Greek). 24. A.P. GRIMANIS, M. VASSILAKI-GRIMANI, M. NICOLAIDOU, Ann. Paed. Clin. Univ. Athens 18 (1971) 233 (in Greek). 25. M. NIKOLAIDOU, A.P. GRIMANIS, M. VASSILAKI-GRIMANI, XIII Intern. Congr. of Paediatrics, Vienna, Genetics vol. 5 (1971) 509. 26. A.P. GRIMANIS, M. NIKOLAIDOU, M. VASSILAKI-GRIMANI, Application of neutron activation analysis in the study of cystic fibrosis. Final Report, IAEA Research Contract 689/RB Athens (1972). 27. C. PAPADOPOULOU, Contribution in the Radioecology of the Greek seas. Trace element determination in edible molliisks. Ph.D. Thesis, Athens University, Athens (1972) pp. 140 (in Greek). 28. A.P. GRIMANIS, G. PAPACOSTIDIS, C. PAPADOPOULOU, M. VASSILAKI-GRIMANI, N. PAPA- CHARALAMBUS, G. PLASSARAS, D. KOTOULASj Neutron activation analysis methods for the determination of 14 trace elements in tissue samples. Results obtained with analytical reference materials in trace elements in relation to cardio- vascular diseases, Technical Report IAEA 157, Vienna (1973) p. 29. 29. C. PAPADOPOULOU, I. HADZISTELIOS, A.P. GRIMANIS, Hellenic Oceanology and Limno- logy. XI (1973) 601 (in Greek). 30. C. PAPADOPOULOU. I. HADZISTELIOS. A.P. GRIMANIS. Hellenic Oceanoloev and Limno- logy XI (1973) 651 . 31. M. NIKOLAIDOU, A.P. GRIMANIS, M. VASSILAKI-GRIMANI, G. ADAM, Ann. Paed. Clin. Univ. Athens 20 (1973) 141. 32. T. HOPKINS, A.P. GRIMANIS, G. PAPACOSTIDIS, T. PAPADOPOULOS, Thalassia Jugosla- vica, 9(1/2) (1973) 219. 33. C. PAPADOPOULOU, A.P. GRIMANIS, I. HADZISTELIOS, Ibid 9(1/2) (1973) 211. 34. A.P. GRIMANIS, Certain aspects of neutron activation analysis as applied to biological materials: Panel meeting on practical aspects of Neutron Activation Analysis, IAEA, Vienna (1973). 14
3B. D. ALEXIOU, Contribution in the study of trace elements in the mother and the newly born baby. Thesis submitted for a Readership at the University of Athens Athens (1974) (in Greek). 36. W. BOCK-WERTHMAN, G. PAPAKOSTIDIS, A.P. GRIMANIS, J. PETROU, D. GEORGIOU, M. VASSILAKI-GRIMANI, "ACTANAL" A comprehensive computer program for routine activation analysis using Ge(Li) detectors. Rept. DEMO 74/15, Greek AEC, NRC Demokritos, Athens (1974). 37. G. PAPACOSTIDIS, A.P. GRIMANIS, D. ZAFIROPOULOS, G.B, GRIGGS, T. HOPKINS, Marine Pollut. Bull. 6(9) (1975) 136. 38. M.I. KARAYANNIS, M. VASSILAKI-GRIMANI, A.P. GRIMANIS; Chimika Chronika, New •Series 3 (1974) 21. 39. D. ALEXIOU, A.P. GRIMANIS, M. GRIMANI, Arch. Med. Soc Athens (1975) p. 234, (in Greek). 40. E. KOUMANTAKIS, The concentration of Zn, Zo and Se in the eyes of the premature and normal newborn babies. M.D. Thesis, Univ. of Athens, Athens (1976) (in Greek). 41. E. BAIRAKTARI-KOURI, Contribution in the study of trace elements, Zn,Fe,Co,Cs, Se.Sb in myomatus uterus. M.D. Thesis University of Athens, Athens (1976) (in Greek). 42. C. PAPADOPOULOU, G.D. KANIAS, Acta Adriatica, Vol. XVIII (1976) 365. 43. C. PAPADOPOULOU, G.D\ KANIAS, E. MORAITOPOULOU-KASSIMATI, Marine Poll. Bull. 7(8) (1976) 143. 44. D. ALEXIOU, A.P. GRIMANIS, M. GRIMANI, G. PAPAEVANGELOU, C. PAPADATOS, Biology of the Neonate, 28 (1976) 191. 45. C. PAPADOPOULOU, G. KANIAS, I. HADZISTELIOS, J. Radioanal. Chem. 31 (1976) 389. 46. A.P. GRIMANIS, M VASSILAKI-GRIMANI, G.B. GRIGGS, Ibid 37 "(1977) 761. 47. A.P. GRIMANIS, M VASSILAKI-GRIKANI, M.I. KARAYANNIS, Ibid 39 (1977) 21. 48. C PAPADOPOULOU, E. KASSIMATI, Thalassia Yugoslavia 13 (1977) 187. 49. C PAPADOPOULOU, G.D. KANIAS, Marine Poll. Bull. 8 (19770 229. 50. D ZAFIROPOULOS, A.P. GRIMANIS, Ibid. 8 (1977) 79. 51 . C PAPADOPOULOU, I, HADZISTELIOS, Rapp. Comm. Int. Mer. Medit. 24 (1977) 89. 52. I HADZISTELIOS, C. PAPADOPOULOU, J. Radioanal. Chem. 36 (1977) 427. 53. D. ALEXIOU, A.P. GRIMANIS, E. KOUMANTAKIS, G. PAPAEVANGELOU, M. GRIMANI, C.PAPA- DATOS, Paediatric Research 11 (1977) 646. 54. A.P. GRIMANIS, D. ZAFIROPOULOS, M. VASSILAKI-GRIMANI, Environmental Science and Technology 12 (1978) 723. 55. A.P. GRIMANIS, M. VASSILAKI-GRIMANI, S. FILIPPAKIS, N. YALOURIS, N. BOSANA- KOUROU, STILI Memorial Volume to N. Kontoleontos (1978) 318 (in Greek). 56. A.P. GRIMANIS, D. ALEXIOU, M. GRIMANI, Paediatriki 41 (1978) 89 (in Greek). 57. D. ALEXIOU, A.P. GRIMANIS, M. GRIMANI, G. PAPAEVANGELOU, E. KOUMANTAKIS, C.PA- PADATOS, Iatriki 33 (1978) 56 (in Greek). 58. A.P. GRIMANIS, C. PAPADOPOULOU, D. ZAFIROPOULOS, M. VASSILAKI-GRIMANI, N. TSI- MENIDIS, IVes JourntSes Etud. Pollution ANTALYA, CIESM (1978) p. 233. 59. C. PAPADOPOULOU, D. ZAFIROPOULOS, I. HADZISTELIOS, C. YANNOPOULOS, M.VASSILAKI- GRIMANI , Ibid (1978) p. 231. 60. A.G. MANOUKAS, A.P. GRIMANIS, B. MAZOMENOS, Ann. Zool. Ecol. Anim. 10 (1978) 123. 61. A.P. GRIMANIS, M. VASSILAKI-GRIMANI, D. ALEXIOU, C. PAPADATOS, Proc. Nuclear Activation Techniques in the Life Sciences, IAEA, Vienna (1978) p. 241. 62. E. BAIRAKTARI-KOURT, C. PAPADOPOULOU, N. PAPACHARALAMBUS, Ibid. IAEA. Vienna (1978) p. 363. 63. G.B. GRIGGS, A.P. GRIMANIS, M. VASSILAKI-GRIMANI, Environment. Geology 2 (1978) 97. 64. G.O. KANIAS, S.M. PHILIANOS, J. Radioanal. Chem. 46 (1978) 87. 65. C. PAPADOPOULOU, G.D. KANIAS, E. MORAITOPOULOU-KASSIMATI, Marine Pollut. Bull. 9 (1978) 106. 66. C. PAPADOPOULOU, I. HADZISTELIOS, Rapp. Comm. Int. Mer. Medit. 25/26 (1970) 5. 67. I. ROUSSOS, A.P. GRIMANIS, S. ECOVOMOU, Memorial volume to Prof. N. Charamis of the Hellenic Opthalmological Society (1979) 117 (in Oeek). 68. G.D. KANIAS, S.M. PHILIANOS, J. Radioanal. Chem. 52 (1979) 389. 69. G.D. KANIAS, A. LOUKIS, S.M. PHILIANOS, Ibid 54 (1979) 103. 70. G.D. KANIAS, Tbid. 60 (1980) 237. 71 . C. PAPADOPOU! OU, G.D. KANIAS, E. MORAITOPOULOU-KASSIMATI, Marine Poll. Bull. 11 (1980) 68. J.S. ANDREOTIS. C. PAPADOPOULOU. Ves .Tourne'es Etud. Pollutions Cagliari, CIESM (1980) 313. 73. A.P. GRIMANIS, D. ZAFIROPOULOS, C. PAPADOPOULOU, M. VASSILAKI-GRIMANI, Ibid. (1980) 407. 74 C. PAPADOPOULOU, D. ZAFIROPOULOS, A.P. GRIMANIS Ibid. (1980) 419. 75. M. ANGELIDIS, A.P. GRIMANIS, D. ZAFIROPOULOS, M. VASSILAKI-GRIMANI, Ibid.(1980) 413. 15
76. C. PAPADOPOULOU, D. ZAFIROPOULOS, Thalassia Yugoslavica 16 (1980) 293 77. A.P. GRIMANIS, S.E. FILIPPAKIS, B. PERDIKATSIS, M. VASSILAKI-GRIMANI, N.BOSANA- KOUROU, J. Archaeological Science 7 (1980) 227. 78. A.P. GRIMANIS, S. ECONOMOU, Proc. Panhellenic Congr. of Opthalmology (1981) 1 8 7a 79. A.P. GRIMANIS, Proc. First Panhellenic Congress of the Hellenic Nuclear Society Athens, Section B21 (1981) 1 (in Greek). 80. A.P. GRIMANIS, Ibid. Section G3 (1981) 1 (in Greek). 81. A.P. GRIMANIS, M. VASSILAKI-GRIMANI, G.D. KANIAS, Proc. 2nd Intern. Flavor Conference, Athens, in: "The Quality of Foods and Beverages Chemistry and Technology, (G. CHARALAMBOUS, G.INGLETT, Eds.) Academic Press N.Y. , vol. 2 (1981) 349. 82. S.E. FILIPPAKIS, A.P. GRIMANIS, B. PERDIKATSIS, Science and Archaeology 23 (1981) 21. 83. M. ANGELIDIS, D. ZAFIROPOULOS, A.P. GRIMANIS, Proc. 1st Intern, Meeting on Environ. Pollution in the Medit. Region, Athens. Publication of the Medit. Scient. Association of Environ. Pollution (1981) 181. 84. D. ZAFIROPOULOS, C. PAPADOPOULOU, M. VASSILAKI-GRIMANI, Ibid. (1981) 187. 85. C. PAPADOPOULOU, I. HADZISTELIOS, M. ZIAKA, D. ZA^IROPOULOS, Rapp. Comm. Int. Mer. Medit. 27 (1981) 135. 86. C. PAPADOPOULOU, C. YANNOPOULOS, I. HADZISTELIOS, Ibid. 27 (1981) 195. 87. A.P. GRIMANIS, G.D. KANIAS, J. Radioanal. Chem. 72 (1982) 587. 88. I. HADZISTELIOS, C. PAPADOPOULOU, Ibid. 72 (1982) 597. 89. K. ANTONIOU. Concentrations of Se, Rb and Zn in maternal and cord blood serum and amniotic fluid of women with normal and prolonged pregnancies. M.D.Thesis, University of Athens (1982). 90. K. ANTONIOU, M. VASSILAKI-GRIMANI, D. LOLIS, A.P. GRIMANIS, J. Radioanal. Chem. 70 (1982) 77. 91. A. KOURIS, Contribution in the study of the trace elements Zn, Fe, Co, Se, Rb, Sb, Ag, Cs, Cr and Se in the human cataractous lenses, M.D. Thesis, Univ. of Athens (1982). 92. G. THEODOSSIADIS, T. KOURIS, C. PAPADOPOULOU, Opthalmic Research 14 (1982) 436. 93. J. ANDREOTIS, C. PAPADOPOULOU, Vies Journees Etud. Pollutions Cannes CIESM (1982) 299. 94. A.P. GRIMANIS, D. ZAFIROPOULOS, C. PAPADOPOULOU, T. ECONOMOU, M. VASSILAKI- GRIMANI, Ibid. (1982) 319. 95. M. ANGELIDIS, D. ZAFIROPOULOS, A.P. GRIMANIS, Ibid. (1982) 339. 96. G.D. KANIAS, Contribution of Neutron Activation Analysis in Pharmaceutical Technology. Determination of active ingredients of drugs. Ph.D. Thesis, Univ. of Athens, Athens (1983) (in Greek). 97. D. ZAFIROPOULOS, Application of Neutron Activation Analysis in studies of trace elements of Saronikos Gulf. Ph.D. Thesis, Univ. of Athens, Athens (1983) 98. E. BAIRACTARI-KOURI, C. PAPADOPOULOU, M. AGAPITOS, N. PAPACHARALAMBUS, Proc. 15th European Congress of Pathology, Hamburg 1983 in "Pathology Research and Practices", 178 (1983) 109. 99. C. PAPADOPOULOU, J. ANDREOTIS, Rapp. Comm. Int. Mer. Medit. 28 (1983) 211. 100. A.P. GRIMANIS, MARIA-VASSILAKI-GRIMANI, G.D. KANIAS, Proc. 3rd Intern. Flavor Conference Corfu, Greece, in "Instrumental Analysis of Foods and Beverages" Recent Progress (G. CHARALAMBOUS, G. INGLETT, Eds.) Academic Press, N.Y., vol. 2 (1983) 323. 101. C. PAPADOPOULOU, Ibid. vol. 1 (1983) 423. 102. G.D. KANIAS, J. Radioanal. and Nucl. Chem. 82/1 (1984) 143. 103. G.D. KANIAS, N.H. CHOULIS, Ibid. 83/2 (1984) 261. 104. A. ECONOMOU, J. ANDREOTIS, C. PAPADOPOULOU, Ibid, (in press). 105. G.D. KANIAS, J. Radioanal. and Nucl. Chem. (in press). 106. G.D. KANIAS, N.H. CHOULIS, Ibid. 88 (1985) 281. GRIMANIS, G.D. 107. D. APOSTOLOV, M. IOVCHEV, L. KINOVA, I. PENEV, E. TASKAEV, A.P Vlles Journees KANIAS, C. PAPADOPOULOU, M. VASSILAKI-GRIMANI, D. ZAFIROPOULOS Etud. Pollution, Lucerne CIESM (in press). 108. C. PAPADOPOULOU, J. ANDREOTIS, M. VASSILAKI-GRIMANI, C. YANNOPOULOS, Ibid, (in press). 109. A.P. GRIMANIS, D. ZAFIROPOULOS, N. KALOGEROPOULOS, M. VASSILAKI-GRIMANI, Ibid, (in press). 110. A.P. GRIMANIS, Proc. Research Coordination Meeting for the HMO/IAEA Joint Research Programme on Trace Elements in Cardiovascular Diseases, Kjeller, Nor-way 19-21 Sept. 1977. 111. L. KORITO, M. SHWACHAMAN, Nature 202 (1964) 501. 112. H. AGEMIAN, A.S.V. CHAU, Analyst 101 (1976) 761. 113. A.P. GRIMANIS, Unpublished data. 114. A.A. KATSANOS, A. XENOULIS, A. HADJIANTGMIOU, R.W. FINK, Nucl. Inst. and Meth. 137 (1976) 119. 115. A.A. KATSANOS, A. HADJIANTONIOU, Ibid. (1978) 469. 116. A.A. KATSANOS (invited review paper) Proc. Nuclear Activation Techniques in the Life Sciences, IAEA, Vienna (1978) 85. 117 Y. MANIATIS, A.A. KATSANOS, ANTHROPOS 7 (1980) 136. 118 A.C. XENOULIS, C.E. DOUKA, T. PARADELLIS, A.A. KATSANOS, J. Radioanal. Chem. 63 (1981) 65. 119 Y. MANIATIS, A.A. KATSANOS, Archaeometry 24 (1982) 191. 120 G.A. MOURKIDES, A.A. KATSANOS, M. TZOUMEZI, Chemistry in Ecology 1 (1983) 245. 121 G. BLONDIAU, J.L. DEBRUN, G. COSTA, A.A. KATSANOS, G. VOURVOPOULOS, Nucl. Inst. and Meth. Bl (1984) 66. 122. N.N. PAPADOPOULOS, J. Radioanal. Chem. 72 (1982) 463. 1=1 In
METHODS
IN
ACTIVATION ANALYSIS EPITHERMAL NEUTRON FLUX DISTRIBUTION AND ITS IMPACT ON {n,T) ACTIVATION ANALYSIS RESULT reactor 1,2 These are:
S.Jovanovic+, F.De Corte++ , A.Simonits+++, L.Moens++, P.Vukotic+, - the moderation takes place in a homogeneous, infinite medium; R.Zejnilovi qQ = "source strength", i.e. number of fission neutrons arriving INTRODUCTION per cm3 and per second at the considered site; After being released by fission of the fuel nuclei, with MeV order ene- { = average logarithmic energy decrement per collision; rgies, neutrons in a thermal reactor undergo successive collisions with the N = number of moderator nuclei per cm; moderator atomic nuclei, losing gradually their energy, down to the thermal I os = microscopic cross-section for elastic scattering ( s=Nus region (meV energies). While in this (moderation or slowing-down) state, ne- is the macroscopic scattering cross-section). utrons contribute to the epithermal spectrum. The exact theoretical treatment of the moderation process is extremely Resonance integral (Io), an essential nuclear parameter when perfo- complicated, due to the multiplicity and complexity of the partial processes rming absolute or comparator type standardization methods in (n,T") reactor involved. However, a fair approximate solution is obtained by introducing neutron activation analysis (NAA), is defined, measured, tabulated in lite- some simplifications, which are more or less adequate for a general thermal rature and should be used assuming ideal (1/E) epithermal flux shape: J (3) Research Associate of the National Fund for Scientific Research, Belgium ECd with In presence of resonance absorption, relation (1), describing the ECd " effective cd cutt-off energy (=o.55eV) epithermal flux distribution is modified to : o e) Inelastic_and_anisotrogic elastic scattering are neglected. This u can be positive or negative, corresponding to a softened or hardened means that solely elastic scattering is considered responsible for the slo- spectrum, respectively, as compared to the ideal one. This is illustrated in wing-down of neutrons. Fig. 2. When plotting log . ""'(E) vs.log E, a straight line is obtained with Inelastic scattering is possible only above the treshold energy which slope = -(1+a). is a few MeV for light nuclei; thus, it does not affect the epithermal spe- The numerical value of a for a given position in a reactor could be, ctrum. in principle, calculated using some of the formulae given in literature . Anisotropic (not spherically symmetric) elastic scattering occurs However, theoretical descriptions of a generally suffer from inevitable (over- with p-wave neutrons (angular momentum = 1) and is considerable above 0.1 MeV. simplifications, the validity of which'varies from one reactor to another, or This effect would increase the 1/E-fiux with increasing energy. even from one irradiation site to another in the same reactor. For practical purposes, experimental a-determination , being general, more accurate and The elastic scattering cross-section {a) is assumed constant (energy relatively simple is a better and already explored alternative. independent) within the epithermal energy region. For light nuclei, used as moderator, this is valid up to~0.1 MeV, or even less (~10 keV for H), as Let us still mention that the 1/E model surely does not fit exactly w the epithermal spectrum shape.It is only a better approximation than the ide- shown in Fig.l. The variation of a% directly influences the e(E) shape [Eqs. (1). (2)1. alized 1/E - form. Detailed error propagation study showed, however, that the 1/E ° model was necessary to employ, but also sufficient for use in absolute We will keep in mind that 0.1 HeV is the upper epithermal energy limit, and comparator NAA 1.4 the region above having little relative importance in practice. f) Moderator atoms are considered as free and at rest before collision THE IMPACT OF EPITHERMAL SPECTRUM DEVIATION ON NAA RESULT with neutrons. This is fair as long as the neutron energies are much above the thermal. Once they are comparable, thermal agitation (and even chemical Since the definition of resonance integral [ Eq.(3)) holds for the id- bindings) of the moderator atoms will affect the spectrum. eal epithermal spectrum, the latter should be corrected for the actual dis- tribution: In practice, however, the lower limit of the epithermal spectrum is de- termined by the "cadmium cut-off energy" (=o.55eV) , thus sufficiently high w = JJ d£ (7) E 7t*a so that the above has no influence on the 1/E shape. Cd 15 So as to describe the real epithermal flux distribution, a semieprirical To convert lQ - yo) the following relation is used : representation a P. " 1.-0.429 a 0.429oo (6) (8) with 0 as in (2) and E (=leV) an arbitrary energy, was introduced ' for its a with simplicity and good agreement with the experimental data. AHMAD recently rela- ted a to the actual properties of a reactor and showedthe physical reasonab- a = (n,Y) cross-section at 22oo m.s neutron velocity; leness of the form (6) chosen. Er= effective resonance energy ~ (in eV), which is characteristic of the isotope. When neglecting the epithermal spectrum nonideality in absolute or CONCLUSION comparator NAA, i.e. when employing Io in place of I0M. an error is made on the analysis result. The magnitude of the error depends on: The nonideality of the epithermal neutron flux distribution should . be taken into account when performing absolute or comparator methods - the isotope, characterized by its E and Q values (Q =I /ff )J r Q 0 0 0 of (n.lf) activation analysis - significant errors could appear otherwi- - the irradiation conditions, determined by f and a; f is the se. Two parameters are sufficient for the correction: a , the measure thermal to epithermal flux ratio (shortly "flux ratio"): f=0t[)/(Je; of the epithermal nonideality and the effective resonance energy (E ), - the comparator used (when applying k - or another comparator characterizing the isotope investigated. method); - the type of analysis, i.e. whether the sample is irradiated in the ACKNOWLEDGEMENTS whole reactor spectrum (reactor neutron activation analysis, RNAA), or with thermal neutrons screened out by Cd - filter (epicadmium neutron The financial support of the National Fund for Scientific Research activation analysis , ENAA). (Belgium) and of the Montenegrin SIZ for Science (Yugoslavia) is highly 14 Since the more detailed error - study overcomes the scope of the appreciated. present paper, let us limit to a few interesting conclusions: - errors are higher than 60% in soma extreme cases; often 5-15" in RNAA and Z5-4o% in ENAA, - errors are larqerin ENAA (Cd-covered activation) than in RNAA (bare REFERENCES activation).This i- due to the fact that in ENAA the whole activity is induced by epithermal neutrons (whose nonideal spectrum causes the error), 1. A.M. WEINBERG, E.P. WIGNER, The Physical Theory of Neutron Chain Reactors, while in RNAA the error is reduced due to the thermal activation contri- The University of Chicago Press, Chicago, 1958 bution. 2. P.SCHUMANN, D.ALBERT, Kernenergie, 2 (1965) 88 - in general, error increases with the absolute value of a ; - errors are larger for isotopes with high Q - factor,than for those 3. A.M.WEINBERG, E.P.WIGNER, Proceedings of the Brookhaven Conference on ones with low QQ.For yery low QQ(e.g. QO<1) the errors are negligible; Resonance Absorption of Neutrons in Nuclear Reactor (BNL-433) 1956 these isotopes do not ask for I_-I.(») correction. 4. J.R.LAMARSH, Nuclear Reactor Theory, Addison-Wesley, Reading, Menlo 18 19 Park, London, Amsterdam, Don Mills, Sydney, 1966 (second printing, 1972) - In single comparator methods (e.g. kQ- ' J, the error reduces for the isotopes whose Qn and E_ values are close to those ones of the compa- 5. G.PLACZEK, Phys. Rev., 69 (1946) 423 rator (e.g. 197Au), since the comparator is exposed to the same epithermal deviation as the isotope analysed. 6. H.GOLDSTEIN.J.A.HARVEY, J.S.STORY, C.H.WEST COTT, Recommended Definitions for Resonance Integral Cross-sections, Rept. EANDC-12 (1961) To correct the analysis result for the epithermal flux nonideality, 7. T.B.RYVES, Metrologia, 5 (1969) 119 the values of a and Er should be known [ Eq.(8}| . As already mentioned, it is relatively easy to determine a experimentally, while Er's can be 8. A.AHMAD, "Evaluation of Neutron Spectra and Activation Data in Thermal found in literature ' or measured independently ' . In most cases the Reactors", Ph. D. Thesis, University of London, Reactor Centre, 1982 remaining error on the analysis result after correction (originating from 9. Guidebook for the ENDF/E-V Nuclear Data Files, EPRI NP-251o Project 975-1 the inaccuracies in a and E - values) is within tolerable limits. p Electric Power Research Institute and BNL, Upton, New York, 1982 10. H.M.R.WILLIAMS, The Slowing Down and Thermalization of Neutrons, North Holland Publishing Co., Amsterdam 1966 11. F.DE CORTE, L.MOENS, K.SORDO-EL HAHMAMI, A.SIMONITS, J.HOSTE. J.Radioanal. Chem., 52/2 (1979) 3o5 100. jfelllll I III] I nil I Illj I nil I nil I III] I nil I Illj I Ml] I III] I lll[j 50. 12. F.DE CORTE, L.MOENS, A.SIMONITS, A.DE WISPELAERE, J.HOSTE, J.Radioanal. Chem., 52/2 (1979) 295 to" 13. F.DE CORTE, K.SORDO-EL HAMMAMI, L.MOENS, A.SIMONITS, A.DE WISPELAERE, i.o J.HOSTE, J.Radioanal. Chem., 62 (1981) 2o9 ±\ ml i nil i ml i ml i nil I nil I nil i nil i nil i nil i ml i ml. 14. S.JOVANOVIC, "The Effective Resonance Energy as a New Parameter in (n,lf) Activation Analysis with Reactor Neutrons", Ph.D. Thesis, Unive- I lll| I I i 11 I lll| I Illj I Illj I III) III!) I I rsity of Gent, 1984. 15. L.MOENS, F.DE CORTE, A.SIMONITS, A.DE WISPELAERE, J.HOSTE, J.Radioanal. "Be Chem., 52 (1979) 379 16. S.JOVANOVIC, F.DE CORTE, L.MOENS, A.SIMONITS, J.HOSTE, J.Radioanal. nil i ml i nil i ml i nil i nil i ml i i Chem., 82/2 (1984) 379 17. F.DE CORTE, S.JOVANOVIC, A.SIMONITS, L.MOENS, J.HOSTE, Atomkernenergie, lll| I ni| i ni| I illj i ni| i in; i ni| I ni| I nijg Kerntechniek 44 (1984) 641. 18. A.SIMONITS, L.MOENS, F.DE CORTE, A.DE WISPELAERE. A.ELEK, J.HOSTE. J.Radioanal. Chem., 6o (198o) 461. i ml i ml i ml i ml i nil 19. L.MOENS, F.DE CORTE, A.DE WISPELAERE, J.HOSTE. A.SIMONITS, A.ELEK. i ml i nil i nil i ml i nil i ml i niu E.SZABO, J.Radioanal. Chem., 82/2 (1984) 385. 2.0-10^- i ni| t MI( i ni| i in; i ni| i ni| i ni[ •! iiij i ni| i iiij i ii 1.0-10 20. S.JOVANOVIC et.al., to be submitted 21. A.SIMONITS, S.JOVANOVIC, F.DE CORTE, L.MOENS, J.HOSTE, J.Radioanal. Chem., 82/1 (1984) 169. 22. S.JOVANOVIC, F.DE CORTE., A.SIMONITS, J.HOSTE, Submitted to J.Radioanal. Nucl.Chem. "I i ml i ml i ml i ml i ml i ml i ml i .ml i ml \ i pH 5 1.0-10' 0010 .010 .10 1.0 10.0 100. 1.0-103 I.0-I05 2.0-10" E (eV) Fig.l. Cross-section functions for elastic scattering of some light nuclei used as moderators -3 6 10 10 10* 10 EleV) Fig.Z. The epithermal neutron spectrum deviation : 1/E 25 THE NEUTRON ACTIVATION ANALYSIS IN THE STUDY OP LANGMUIR- BLODGETT MULTILAYERS COMPOSITION - RELATION TO OTHER METHODS OS INVESTIGATION J.G.Petrov, I.Kuleff Faculty of Chemistry, University of Sofia, 1, Anton Ivanov ave., 1126 Sofia, Bulgaria Langmuir-Blodgett multilayers are molecular structures built up in a con- trolled manner by means of irreversible transfer of monolayers of insoluble and non-volatile organic compounds from a liquid/gas onto a solid/gas interface/1,2/. These lamellar systems are used as gratings for soft X-rays, ion selective mem- branes, mioroeleotronic gas sensors, electroluminescence panels, tunnelling de- vices, etc /3/. The controlled distance between the functional groups has been utilized in many fundamental studies dealing with energy transfer, light inter- ference effects and other optical and electrooptleal phenomena /4/.Incorporation of enzymes, proteins and antibodies in such assemblies models different biolo- gical systems and enables the investigation of enzyme - substrate and immunolo- gical reactions. Long chain fatty acids and their bivalent soaps are commonly used to build up multilayers of good quality /2/. Recently long chain ammonium salts have been also successfully applied /5,6/. These compounds ca2 n be 2irreversiblz+ y transferre2 d only if the aqueous subsolutians contain Cd2+,9Ca , Ba , Cu or Pb * (in the case of fatty acids) and HPO. , HAsO.2-, CrO^" or S0.2- (when long chain amines are used). The above counter ions play 5 decisive role also in the struct- ure and stability of the systems created /7/. For this reason an investigation of the counterions bonded in multilayers of ionic surfactants proves Important for the understanding of the mechanism of their formation and for finding the factors which determine their structure and stability. In /8-11/ we have performed neutron-activation analysis of the composition of several LB Bystems making use of the high sensitivity of the method as well as of the fact that these samples are rather appropriate for ItB application. The present,paper compares the features of this method with those of other analytical techniques used in the study of LB multylayerB, pointing out the a «o nfoft0l}id ?e al+° Btressed *£a* NAA Provides information about the total amouna U t of the Belements analysed, being unable to distinguish their valenFlifaW ,,. *tdlOm!tf1C/?alva''R f™A * The h1^ sensitivity which can be IcMevef by detection of ionizing radiations enables the reliable application of the radio metric analysis in the study of the multilayer stoichiomitry. UnLrtuSfely the tagging technique was used for this purpose on a limited scale (^Ca^In dea- rie acid multilayers /13/) regardless of the fact that all the elements of in! terest (except for Mg) have appropriate radionuclides. May be this is due to the obstacles by the absolute radioactivity measurements and/or to the necessity ex- periments with great amounts of radioactive solutions to be carried out. These obstacles can be avoided by standartizing the radioactivity measurements and de- termining the specific rate of counting (the rate of counting per unit of mass) /14/« An increase of the measurement efficiency through reduction of the area of counting without diminishing the radiation intensity can be achieved by means of the detachment technique proposed in /8/. The difficulties due to self absorp- tion which arise in this cage can bgoCorrected /15/ or the measurements of the pure /?-emittance of -^S, 45Ca and •>*? can be performed witl. liquid scintilla- tion counting /16/. Some competitive ionic reactions might also be studied by means of RMA when gamma speotrometry is used. In the case of Ca it is possible to work with T'Ca but S and P do not offer any convenient radioactive isotopes. The tagging compounds are commercially available /17/ or can be obtained by irradiation with neutrons of appropriate targets in a nuclear reactor /18/. It should be mentioned, however, that the radionuclide and the stable ion can differ in their chemical forms in solution /19/. This is to be expected particu- larly when inorganic anions are analysed in multilayers of cationic surfactants. Spectrophotometrv (SPh/r A spectrophotometric determination of Cd2+ in multilayers of aracnidic acid was carried out in /20/. The multilayer was remo- ved from the glass substrate by treatment with saturated solution of HC1 in chloroform and Cd2+ was determined as a diphenylthiocarbazone complex. By means of the same removal procedure other counterions can be analysed if stable enough complexes with high extinction coefficients can be formed in chloroform media. Thus 5-Br-pyridylazo-diethyl aminophenol (5-Br-PADAP) can be applied for the determination of heavy metalB (CU2+, Zn2+, Pb2+, Ba2+) since it gives stable red complexes with £ * 10?, IR-Speqtroscopy (IRS): This is a nondestructive method providing a detail- ed information about the organic constituent of the multilayers. In the systems built up of long chain ammonium salts it can also detect the inorganic anions (if they have individual vibrational frequences /21/) identifying their valent form. When multilayers of fatty acid soapB are studied, the binding of the in- organic cations is determined Indirectly, analysing the ratio of the absorban- ces of the dissociated (1583 cm"1) to non-dissociated (1710 cm"1) carboxylic groups /22/. In addition to the ab.ove information, the IR-spectra furnish evidence for basic salt formation (peaks of the OH group at 3340 and 3715 cm"1 /22,23/, oo- ordinative binding of the metal ions (the specific shape of the bands above 1500 cm-1 /24/), hydrogen bonds (broadening of the bands and shift of Vmax t° lower frequences /21/), hydration water (a split carboxyl peak at 1580 and 1540 cm-1 /23/), etc. Sometimes polarized IR radiation is applied /25/ in order to study the structure of the multilayers. Infrared dichroism was also measured in /26/. It enables a eonformational analysis of L- aC.-dipalmitoyl phosphatidyl- ethanolamine multilayers to be performed. Earlier studies utilized transmission IR-speotroscopy of multilayers depo- sited on CaF2, AgCl or ZnS substrates (250-300 monolayers on each side). Now- adays the ATR technique makes it possible to obtain measurable absorbance from severalll/27l monolayers only /d(/./ ,„.„.» _. . - . .„.„ Electron Spectroscopy for Ohemical Analysis (ESCA); Except for hydrogen, all the elements may be identified by this method /SJB/. Although the absolute sensitivity of the method is very high (-1 - 10 ng for most elements), the relative content in the sample is usually determined. Since the emitted elec- trons are easily stopped, ESGA provides information about the last few mono- layers of the LB system (of thickness < 100 I/. This helps to avoid the influ- ence of the subetra-te and to obtain a "pure" signal after the Jepositxon of several monolayers only but diminishes the relative accuracy of Jft£ method. The ESCA spectra give the composition, valent state and binding ene^ies of the atoms in the multilayer. When they are recorded at low angles << 3U ; defectB in the multilayers structure can be identified /2y/. 27 i:SCA was applied to IB multilayers in several studies which made use of their definite thickness to standartize the method /30/ and for some fundamental in- vestigations of electron wave lengths in metals and polymers /29,31/. The stoi- chiometry of the Cd arachidate multilayers used was also determined from the in- tensity ratios on C(1S), 0(1S) and Cd(3d) levels. The shifts of the C(1S) elec- tron energies in CH2, COOH and COO- were used to obtain the degree of ionization of the earboxyl group. The application of ESCA to LB systems requires special care to be taken of their possible "skeletonization" (evaporation of the fatty acid molecules) in vacuum /32/. This effect changes the ratio fatty acid/bivalent soap, resp. the stoichiometric relationship in the multilayer, OTHER POSSIBILITIES There are some other unemployed possibilities for the accurate determina- tion of the inorganic components of the IS systems. These components (except for P and S) are among the 30 elements which are particularly appropriate to be ana- lysed by means of the Atomic Absorption Spectrometry /33/. The practical appli- cation of this method reouires a quantitative dissolution of the multilayers. This procedure can be performed if the latters are deposited onto a glass sup- port covered with a polystyrene foil. As described in /8/f this foil can be easily detached and transferred into a small (10 ml) volumetric flask with an appropriate solvent (xylene, methylisobutyllcetone, hexone). The Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) has the main advantage of NAA (possibility for the simultaneous determination of several elements) at a still higher, by an order of magnitude, sensitivity (Tab- le l)/34/. The determination is very quick and efficient, allowing all the inor- ganic ions in the multilayers to be analysed. Here also the dissolution proce- dure recommended for the application of AAS should be performed. COMPARISON OP THE METHODS IR-spectroscopy has been most often applied in the investigation of LB multilayers probably due to the fact that besides the stoichiometry many other problems can be solved by its use. When multilayers of long chain ammonium salts are studied, IRS provides information both for the organic and inorganic compo- nents, giving also the valent states of the latters. If however an accurate de- termination of the multilayers eornpo-sition is •ainreu, additional- anelyBie of-the counterions should be performed. The parallel application of another analytical technique is obligatory when IRS is applied to fatty acid multilayers. In this case the IR spectra indicate the organic molecules only and an independent investigation of the content of in- organic cations proves necessary. NAA, ICP-AES, AAS and RMA possess very high sensitivities and following the practical recommendations given above they can be applied successfully for this purpose. The first two methodB are to be prefer- red when multicomponent (with respect to the counterions) systems are studied and AAS and RMA are convenient if individual elements are determined. In some cases spectrophotometry, which can be applied without special instrumentation and qualification, gives also accurate results. The possibility to analyse both the organic and inorganic components of the multilayers makes ESCA suitable for their complex investigation, providing that thev are not affeoted by the vacuum treatment. However, the stopping of the emitted electrons by their passage through 3-4 monolayers only restricts the amount of the analysed material and strongly decreases the «»curaer of the stoi- chiometric determination. For this reason the most important information yielded by this method concerns the binding energies of the atoms in the LB system. Summarizing all above statements, a conclusion can be drawn that if the structure of thi multilayers, their stability, the molecular interactions orthe binding energies of the elements are to be studied, IRS and ESCA methods should be applied, for a plausible determination of the multilayers composition, how- ever* the inorganic content should be analysed accurately by means of one of the and 1:2 for mono- and bivalent counterions. 28 'Jafrle I Element NAA /35/ RMA AAS /33/ ICP-AES /34/ Ba 80 ng (++) Ba-131 (++) 8 ng/ml (+++) 1 n<*/E'l (+++)" 1 0.37 Ba 6 18 1 Ca 120 ng (+) Ca-45 (++) 0.5 ng/ml(+++) 1.6 ng/ml (+++) 90 1 0.04 Ba 2 5 Cd 6 ng (+++) Cd-115m (++) 1 ng/ml (+++) 0.06 ng/ml(+++) 2 1 0.02 Ba 1 Cu 0.04 ng (+++) Cu-64 (+) 2 ng/ml (++) 1 ng/ml (++) 1 1 0.42 Bo 4 2 K 50 ng (++) K-42 (+) 2 ng/rol (+++) 1.5 ng/ml (+++) 38 1 0.44 Ba 6 4 Mg 12 ng (+) - 0.1 ng/ml(+++) 1.5 ng/ml (++) 15 1 7 Na 0.08 ng (+++) Na-24 (+) 0.2 ng/ml(+++) 7 ng/ml (++) 1 1 0.64 Ba 1 33 Pb 14000 ng (-) Pb-210 (++) 10 ng/ml (+++) 2 ng/ml (+++) 2000 1 5.73 Bq 6 1 • Zn 1 ng (+++) Zn-65 (++) 1 ng/ml (++) 0.2 ng/ml (++) 1 1 0.61 Ba 2 1 As 0.03 ng (+++) As-76 (++) 0.2 ng/ml(++) 3 ng/ml (++) 1 1 0.40 Bq 1 5 8 ng (+++) Cr-51 (++) 3 ng/ml (++) C.4 ng/ial (++) Cr 5 1 0.68 Bq 6 1 0.5 ng (+++) P_32 (++) 1.106ng/ml (-) ^ng/g <++) P 1 1 0.43 Ba 580 S 16000 ng (-) S-35 (+++) - 0.2 ng/c (+++) 15000 1 0.48 Bq 1 (+) measure of the applicability of the method. REFERENCES hi K.B.Blodgett, I.Langmuir, Phys.Rev.,51 (1937)964 ; /2/V.IC.Srivastava, Physics of Thin Films,7(1973)340; /3/G.G.Roberts, P.S.Vinsett.Y'.A.Barlow.Phys.Technol., 12(1981)69; /4/H.Kuhn,D.I,Sbius,H.BUcher,Physical Methods of Chemistry,Pert III, A.V;eisBberger,B.V/.Rossiter(Eds.),V/iley-Intersci.,NY,1972; /5/J.G,Petrov,H.l Chim.Scand.120(1966)2880; /31/T.0hniski,A.Ishin,, mura.J.Phys.Chem. ,82(1978)1989; /32/S.J.Gregg,E.E.Widdowson.Kature,144(1939)666 /33/J.navezov,D.Zalev,Atomic Absorption Analysis, Nauka i Izkustvo,Sofia,1980; G.E.Kirkbright in"Elemental Analysis of Biological Materials,IAEA,Vienna,19B0, p. 141; /34/V/.J.Haas,V.A.FasBel,i"bid. p. 167; /35/V.P.Guinn,ibid. p. 105; /36/L.A. Currie,Anal.Chem.,40(1968)586. 29 JJUJTROH AOTHTATIOH AHALYBI8 OF SIMTOOBDUOTOR SILICON 8* Apostolescu, Ana Pantelica, Maria S&lagean Institute for Physios and Nuclear Inglneerlng Bucharest WS-6, Romania Abstraoti 8oaw romanian semiconductor grade ailicon elides were analysed by IHAA. Surface and volume contaminations of the samples nave been studied. IHfRCDUOflON The analysis of impurity oontenta in semiconductor materials is an impor- tant problem since it ia known that small quantities of these impurities oan drastically change their mechanical and eleotrlcal properties, IXFBRXIBNTAL Many samples of semiconductor silicon slides of various types and diffe- rent proveniences have been analysed. She analysis of only four romanian semi- conductor silicon samples produced by the Institute for Research and Produc- tion of Semiconductor Materials is presented in this paper. She samples of n or p types materials having the resistivities between 40-ft-on and 1.4 Eftem were irradiated for 40 hours in a 1.4zl01?n/om2.s. flux. Before the irradia- tion the silicon slides were very oleaned and washed. A solution of 0.105 ug of Au and Soll-5 were used as standards. After 4-5 days ooollng time the measurements have been carried out by using a Ge(UL) deteotor with 2 keV reso- lution coupled to a multichannel analyser. A gamma spectrum of the sample nr.3 measured for 2 hours after 4 days deoay time is shown in figure 1. R1SULTS ADD DISOUSSIGH As, Au, Br, Oo, Or, Ga. Ef, Mo, Ha, 8b, Zn, ff elements were found out. from another epeotrum of this sample, Ye oould also be measured. Besides the elements before mentioned, Bo end-Hi arc present in some of the samples. The results expressed in lO^atoms/onF are given in table 1. fhe samples labeled 4 and 5 are the same type of semloonduotor silioon, the difference consisting only in the way the samples have been treated prior to the irradiation. Number 4 was very well washed in deionlsed water while number 5 was et- phed in a 3 i 1 i 1 mixture of acids (010., HF, 0H.0OOH, respectively). All the other samples were etched in the abovf mlxiure'of aoids. She impurity con- tents are smaller in the sample 5 as compared to the number 4 as oan be seen. After these first measurements the samples have been ctohed for 5 minutes in a 5 i 3 I 3 mixture of aoids (HHOx, HF, OHzOOOH, respectively) and very thorougly washed in a shower of water. Measurements of 5 - 6 hours have been oarried out for eaoh sample, fhe concentration of the elements present into the volume of the samples is presented in table 2, Results are expressed In ppb. A study of the variation of some element contents with suoceslve etchings of the samples after irradiation, is also presented in tabel 3. For this study the two samples namely 4 and 5 were ohosen, I.e. the same type of silioon pre- pared in different ways before irradiation, fhe results are expressed in 1012 atoms. She Buocesive etchings of 2 minutes in a 5 i 3 i 3 mixture of aoids were oarried out. After the first etching a high decreasing of the element contents oan be observed. A surface contamination of the silioon slides during outting, polishing, washing and handling before and after their irradiation oan be oonoluded. After the second etching, element oontents decreased In a variable ratio In 1 - 4 region while the third etching reveals that the sample elemental con- tents remains oonstant suggesting no further surface contamination. A high content of the elements on the surface of the semloonduotor sili- oon slides does Indeed exist. An etching of 5 minutes after the sample Irradia- tion In a 5 i 3 » 3 mixture of aoids reveals only the volume contamination of silicon semiconductor slides. TABU 1 - Slemental oontent (lO^atome/om2) 0 1 2 3 4 5 AS 0.08+0.02 0.12+0.04 0.08+0.03 0.5+0.1 AU 0.0280+0*0006 0.0150+0.0003 0.0110+0.0002 32.1+0.4 0.243+0.005 30 0 1 2 3 4 5 Br - 1.63+0,09 1.57+0.09 _ „ Go 0.7+0.1 0.9+0.1 1.3+0.* 9.3+1.6 1.1+0.7 Or 7.3+0.9 3*6+0.6 3.5+0.6 - - v« 80+40 67*60 132+65 - - Ga - 1.4+0.4 0.6+0.3 0.06+0.01 0.07+0.02 Hf 1.5+0.1 - 0.03+0.01 - - Ho 0.49+0.05 0.82+0.08 0.62+0.01 14.1+3.5 2.2+0.7 Ha 218+25 148+18 170+21 827+21 117+4 Hi 12+2 - - 23+13 - 8b 0.024+0.006 0.031+0.006 O.O15+O.OO3 0.21+0.06 - Bo 0.050+0.005 - - - - Zn 17+3 40+7 47+6 194+92 - W 0.44+0.07 1.0+0.2 1.8+0.3 26.2+0.3 4.8+0.1 q»A?Tl 2 - llemental concentration (ppb) Saapl* in Mo ffa W 1 0.051+0.004 2 0.005+0.,002 - - - 3 0.003+0,,001 - - - 4 0.0032+0..0003 0.03+0.01 0,49+0.07 0.013+0.003 5 O.OO29+O.OOO2 O.O5+O.O2 0.50+0.02 - TABU 3 - Variation of aoiu element oontenta (10 atoms) with auooealve etohinge of the aaaplaa after irradiation Sample 4 •lament Xton-etohing Piret etching Second etching Third etolling Au 32.1+0.4 0.0229+0.0006 0.0050+.0.OOO4 0. 0038+0.0004 Ifo 14.1+3.4 0.103+0.069 0.0589+0.0466 0. 0685+0.0342 Ha 827+21 6.5+9.B 5.91+0.73 5.1+0.7 w 26.2+0.3 0.024+0.005 0.0139+0.0038 0. 0163+0.0050 Sample 5 Element Non-etohing First etching Second etohing IMrd etching Au 0.24+0.01 0.00666+0.00053 0. 00243+0.00032 0.0030+0.0002 Ho. 2.2+0.7 0.286+0.066 0.108+0.053 0.1172+0.0486 Ha 117+9 5.27+0.64 4.79*0.54 4.52+0.72 W 4.8+0.1 0.O055+O.OO19 0. 00286+0.00137 — COUNTS / CHANNEL "mTc(Mol 206 187W 221 82Br 198'Au 479 m z m 685187W a? o 77682Br 828 82Br 834 72Oa -1044828r 1115 65Zn r 1173 60Co J31782Br ^—1332 60r.o • 1368 32 DETERMINATION OF SOME TRhCE ELEMENTS IN BIOLOGICAL MATERIALS USING THE SHORT LIVED ISOTOPES E.Taskaev Institute of Nuclear Research & Nuclear Energy, boul.Lenin No 72, Sofia - 11B4 Studying the trace elements in biology the necessity of vanadium determination often arise (1,2). Its instrumental determination is practically impossible uith acceptable accuracy in most of the cases. Radio- chemical separation is necessary. Some good procedures for vanadium determi- nation uere proposed (2-5) and the one from Byrne and Kosta (2) was chosen. Determination of some other biologically active elements together uith V is of interest too. Preparing the sample for analysis and analyzing it for vanadium, the analyst does the majior part of the uork. So, it is uorthuhile to do some more separation procedures and get additional information. Radiochemical procedure uas even preferable as the errors of instrumental determination for these elements (e.g. Cu, fin, Flo etc.) are often bigger than their concen- tration changes in the organs due to bioprocesses. It uas decided to continue the processing of the sample and to separate Cu, fin, Rb and K. Molibdenum uas isolated together uith vanadium, and consecutive extraction uas used for Cu and fin diethy1-dithiocarbamate complexes (6,7) . Sodium tetraphenylborate (Kalignost) uas used for the precipitation of Rb and K (B) . Standard reference materials SRM-1577 Bovine Liver, SRM-1571 Orchard Leaves and Bouen's Kale were analysed, and the procedure uas used for the analysis of breast cancer tumors. EXPERIMENTAL Irradiation. Samples' tablets about 300 mg Bach were irradiated uith ICIS pneumatic sample irradiation system of University of London Reactor Centre (Ascot, GB) . Irradiation time uas 5 min. Irradiation uas carried out in mixed neutron flux: 1.7»1012 thermal neutrons.cm-2.s~1 and 9• 1D11 fast neutrons.om~^.s~'' (9). Samples reached the radiochemical laboratory by pneumotube immediatly after irradiation. Dissolution. Uet ashing procedure (2) uas usBd for the dissolution. Cnly some differences from (2) uill be mentioned. Carriers for all separated elements uere put into Kjeldahl flask before dissolution as usualy: V - 400 jjg, Mo - 600 ug, Cu - 3 mg and Rb - 10 mg. 54-Rn and 137-Cs tracers uere added for chemical yield determination. The solution uas dried before sample and acids uere added to the flask. Solution of KMnO4 used in dissolution procedure uas at the same time the carrier for fin and K. The extraction of M, Mo, Cu and fin uas carried out in siple and effective extractor, fig.1. Since V uas separated together uith flo, GeLi and multichannel analyser uere used. The contents of the other BlemBnts uere much higher than the M content and GeLi uas effective enough for counting all of them. Samples and standards uere counted in 25 ml volume flasks, except V and Mo for which 10 ml flasks uere USBC). Separation of \l and flo. Vanadium and molib- denum uere extracted uith 0.1% N-benzoyl-N- phenylhydroxylamina (BPHA) solution in toluene (2). Organic phase uas counted for 500s and 52-V ( Ti/2=3.75 min Ey=1434 kev) uas measured, then it uas counted again for 600s and 101-Mo Fig.1. Extractor ( T1./2=14.6 min E^=192 kev) uas measured. The chemical yields ware controled by irradiation of 0.5 ml aliquotes of organic phases. Separation of Cu. The pH of the aqueous phase uas adjusted at 5 uith NaOH. Copper uas extracted uith tuo 10 ml portions of 3.5* 10—^TO solution of Pb(DDC)2 in CHCI3. Extracts uere gathered, uashed and counted. 511 kev of 64-Cu uas used for thB computation. Counting time uas 5 min. Chemical yield uas controled by irradiation of aliquotes. Separation of fin. About 200 mg of NaDDC uere added to the extractor 33 and manganese uas extracted with tuo 10 ml portions of CHCI3. Extracts uere gathered, uashed and counted for 5 min. 846 kev line of 56-Mn uas used for the determination. 54-Mn activity uas measured for 900s and B34 kev peak uas used for the calculation of chemical yield after decay of 56-Mn. Separation of K and Rb. The water phase left- uas transfered in glass beaker and 20 ml of 0.10 sodium tetraphsnylborate (Kalignost) solution uere added to precipitate K and Rb. The solubility of KB(C6H5)4 and RbB(CfiH5)4 could be lessened by decreasing the temperature of the solution using the ice bath and uith the surplus of precipitant. The precipitate uas filtrated and uashed uith cold 0.011*1 Kalignost solution. Then it uas dissolved in ace- tone and transfered into the flask for measurement. Both lines of 88—Rh ( T1/2=17.B min) B98 ke\» and 1836 kev were used for the analysis. After decay of 88-Rb samples uere counted once mote for 600s and 1.524 kev line of 4 2-K and 661 kev line of 137-Cs uere measured. Chemical solutions uere used as comparative standards for all listed elements. RESULTS AND DISCUSSION The trace experiments uere carried out uith animal and plant matrixes, in order to study the chemical yields for all the elements. The error of 3% (0.05 confidence level) for single determination of chemical yield uas chosen as the highest value accatable. Houever, this value uas not reached for any of the elements. It should be noticed that the yields in case of plant matrix uere constantly louer (exept for Rh and K) than for the animal one. The louest value uas obtained for Mo (88.7*9.8 %). So, it uas decided to control the chemical yields in each case. Since the irradiation of organic aliquotes uas chosen for W, Wo and Cu yield determination, the content of these elements in the sample should be taken into account. The quantity of carriers corresponded uith the content of the element in the sample. It uas necessary to increase the amount of Cu carrier, for example, up to 3 mg because the Cu content in the sample could be high (e.g. up to hundreds ppm). The possibility of using 137-Cs tracer for K and Rb chemical yield deter- mination uas also checked. The solubility of KB(Ph)^ uas about 4 times higher than the one of CsB(Ph)4 (B), but in BXCBSS of NaB(Ph)4 and louered tempera- ture of the solution less than 0.1$ of initial potassium could be found in the solution. That alloued to use the 137-Cs tracer to control the K chemical yield. That uas even more applicable to Rb. Special attention had to be paied to the chemical standards. They gave the possibility to get lou counting statistic error (belou "\%), but on the other hand they could aluays cause sistematic errors (9) . The standards uere treated in the simplest way. Polythene capsule uith dried irradiated standard uas treated in glass beaker uith appropriate mixture (usually strong acids). Table 1. Results from 6 independed determination for 5RM (in ppm). SRM-1577 Bovine LivBr SRM-1571 Orchard Leaves] Bouen* s Kale EL this uork I raf.(H) this uork ref.(i2) this uork i ref.(iO) x±2«SD I x± 2«SD x± 2«SD I V 0.051*0.009 0.05861. 0.41110.038 0.471 ].3640.05 0.37640.013(2) 0.0016(2) 0.01.4(2) 0.3610.04(10) rio 2.7±0.6 3.4(11) 0.2240.05 0.310.1 2.210.6 2.3010.21 Cu 1B7*12 193*10 12.510.7 12*1 4.99*032 4.9010.42 fin 9.7*0.6 10.3t1D 93*6 91*4 1.3.9+0.9 15.0*1.2 Rb 17.9*2.1 18.3*1.0 11.241.3 12*1 55.216.4 52.0*5.2 K 9400*1000 9700*600 14200+660 14700*300 245004970 24300*120 Active solution uas quantitatively transfered to the volume flask for counting. The capsule uas checked for the activity left. To check the uhole procedure thB standard reference materials SRFI-1577 Bovine Liver, SRM-1571 Orchard Leaves and Bouen's Kale uere analyzed. Results are shoun in Table 1. Breast cancer tumors had been analyzed using the discribed procedure. ACKNOWLEDGEMENT The author thanks Dr. N.Spyrou for most useful discussions, the Univer- sity of London Reactor Centre staff for their assistance and The International Atomic Energy Agency, Vienna, for financial support* 34 REFERENCE 1. Bengtsson S. and G.Tyler, MARC Technical Report, (1976) 2. Byrne A.R., L.Kosta, 3 .Radioanal. ChenT., 44 (197B)247 3. Heydorn K.,H.R.Luken3, Risö Report, 13B (1966) 4. Kaiser D.G., U.U.Weinke, Anal.Chim.Acta 29 (1973) 211 5. Steinnes E., IAEA Tachn.Report 157, Vienna (1973) p 149 6. Bajo S. and A.Uyttenbach, Anal.Chem., V48 No6 (1976) 902 7. Shen L.H. and S.J.Yeh, J.M.Lo, Anal.Chem. V52 No12 (l980) 1S82 8. Plusheu U.E., B.D.Stepin, "Analytical Chemistry of Rb and Cs", Nauka (1975) Moscou, pp 59-61 ( in russion ) 9. Burholt G.D., "The University of London Reactor", ULRC/OPS/4 10. Parr R.M., IAEA/RL/103, Sept.1983 11. Certificate of Analysis, National Bureau of Standards, SRPl-1577,reu. 1977 12. Certificate of Analysis, National Bureau of Standards, SRM-1571,reu.1977 35 Se IN BIOLOGICAL SRM's: A COMPARISON OF RESULTS OBTAINED BY DIFFERENT NEUTRON ACTIVATION METHODS M.Dermelj, A.Gosar, M.Franko, A.R.Byrne, L.Kosta, P.Stegnar Faculty of Natural Sciences and Technology and "J.Stefan" Institute, "E.Kardelj" University Ljubljana, 61000 Ljubljana, Yugoslavia INTRODUCTION wi the basis of various studies and research, since I960 selenium has been included among the micronutritients considered essential for living organisms III. Currently, intensive research is being carried out to elucidate its role in enzymatic processes, its nutritional importance, its antagonistic interactions with other elements.as well as its toxicology. ' Thus there is an important need for developing rapid and sensitive analytical methods for Se which give accurate and reproducible results in a variety of biological materials. In this work we present and compare results for selenium obtained in various IAEA and NBS biological standard reference materials obtained by instrumental neutron activation ana- lysis (INAA) and different radiochemical neutron activation methods (RNAA) developed in our laboratory. EXPERIMENTAL 1. Irradiation: lyophilized and homogenized samples were irradiated in plastic or silica tubes, together with a selenium standard, in the rotating rack of the 1 2 1 Institute is Triga Mark II reactor at a flux of 2.10 2n.cm- s- for 20-40 hours. 2. INAA: The V-activity of the '5se isotope, T1/2 = 120d; E^= 0.121, 0.136, 0.264, 0.279 and 0.401 MeV, was measured on a Ge-Li detector (efficiency 17%, resolution 1.0 KeV for 60co) connected to a Canberra 80 4000 channel analyser. The 0.13b and 0.264 MeV peaks were both used for calculation. 3. RNAA: For radiochemical determination of selenium in various biological samples the following methods, developed in our laboratory can be used: a) pyrolysis of the sample, volatilization, trapping on soda lime 121 b) wet destruction (H2SO4, HNO3 and H2O2) or oxygen combustion of the sample, extraction of Se(IV) carbamate into toluene or CCI14 111. c) destruction of the sample with saturated Mg(N03)2, reduction of Se(VI) to Se(IV) with 6M HC1, reaction of Se(IV) witfi S-nitro-o-phenylene diamine (4-NDP) and extraction of the resulting piazselenol with toluene or CCI4 /4/. The if-activity of the 75& isotope in samples and standards was measured on a "3x3" well-type Nal(Tl) detector connected to a 400 channel analyser, and the area of 0.400 MsV sum peak used for calculation. The chemical yield which is about 85-90% was determined either on the basis of tracer experiments, or by a short reactivation of the organic phase (toluene) using the short-lived selenium isotope °lmse (T1/2 = 57 min; E^ = 0.103 MeV). RESULTS AND DISCUSSION The best means of achieving accuracy in trace element analysis is to apply the methods developed in the laboratory to the analysis of SRMts and to compare the results obtained with the certified values. From the results obtained for Se in different IAEA and NBS standard reference materials, presented in the attached table, all the methods developed in our laboratory show good repro- ducibility and give good agreement with certified values. The advantage of 4-NDP method is that, unlike the other techniques, it can be applied after only 1-2 days "cooling" of the sample, and also can be combined with solvent extraction of other trace elements. REFERENCES III E.J.Underwood: "Trace Elements in Human and Animal Nutrition". 4tnEd.,AP, New York 1977. 121 A.R.Byrne, L.Kbsta: Talanta, 21 (1974) IO83. Ill H.Polkowska-Nbtrenko, M.Dermelj, A.R.Byrne, A.Fajgelj, P.Stegnar, L.Kosta: Radiochem. Radioanal.Letters, 53 (1982) 319. /4/ M.Dermelj, A.Gosar, M.Franko, L.Kosta (in preparation for press). 36 Table I. Comparison results for Se in Reference Materials (in Methods and techniques Certified SAMPLE R N A A INAA values or wet oxygen range pyrolysis destruction combustion 4-NDP IAEA MAA-1 3.16*0.20 3.80*0.40 3.25*0.19 _ _ - Copepod homogenate (n=6) (n=12) (n=7) IAEA MAM-1 2 .36*0.25 2.24±0.29 2.32*0.21 - - m = 2.1 Oyster homogenate (n=6) (n=7) (n=3) r = 0.05-2.82 IAEA MAM-2 1.94*0.11 _ 1.63*0.23 2.08*0.14 - Missels (n=5) (n=9) (n=10) IAEA MAA-2 1.08*0.07 0.98*0.04 _ _ Fish muscle (n=6) (n=10) IAEA H-8 4.87^0.56 _ 4 36±O 24 _ 4.67*O.96x Horse kidney (n=6) (n=6)' NBS SRM 1567 0.650*0.073 0.705*0.065 0.779*0.065 1.1*0.2 Wheat Flour (n=5) (n=l8) (n=8) . NBS SRM 1577 1.11*0.05 1.06*0.11 1 10*0 13 1.00*0.07 1.13*0.04 1.1*0.1 Bovine Liver (n=6) (n=ll) "(nz5) (n=10) (nz5) Note: m = median r r range x = overall mean 37 14 MeV PHOTON ACTIVATION FOB PROTEIN ANALYSIS IN CEREALS B. Oonstantinescu, B. Ivanov, D. Plostinaru, A. Popa-Nemoiu G. Paseovioi Institute for Physios and Nuclear Enginearing Bucharest MG-6, Romania INTRODUCTION The nutritional value for the agricultural products is mainly characte- rised by their total protein content* Nitrogen tc protein content in cereals is related by a 6*25 conversion factor* Thus nitrogen determination in cereals is equivalent to protein analysis. The olassioal nitrogen analysis method is the Kjeldahl chemical technique, which ia time-consuming, destructive and not suitable for a large number of samples* A fast nuolear nondestructive method for protein analysis using the 14 MeV proton activation to measure total nitrogen content through the reaction* 14N (p,n) 140 (Tj^ = 71 a) has been developed in our laboratory* The 14-0 activity is detected by means of its characteristic 2.312 MeV gamma-ray line with a Nal(Tl) detector* She number of gamma-rays to the inci- dent particles ratio for one sample, related to a similar ratio for the adequa- te standards helpj to determine the nitrogen content in that sample. EXPERIMENTAL A beam of 14 MeV protons, produoed by the IHPK U-120 variable-energy fixed- frequency Cyclotron passes through a 50 nm aluminum foil window into the air* Directly behind the window, the irradiation chamber is located, acting also as a Faraday oup* She effective irradiated and analysed mass of the grain is deter- mined by the difference in range of the protons at 14 MeV and at the reaction threshold (^ 6.4 MeV) and amounts to ~ 0*2 g/em2 (1.4 mm for wheat and barley, 1*2 - 1*? mm for corn and soya - beans)* The proton beam hitting the sample (100 + 10 nA) is measured by the charge collected on the Faraday cup. A grain sample to be analysed is first put into a disposable aluminum con- tainer approximately 25 mm in diameter and 22 mm in length* For a fast determination samples in a large number the automation of the operations was necessary* A mechanized system able to analyse samples at a rate of one per minute (see Fig.l) has been developed* She sample 1B gravitationally transported from the magazine to the irradiation area in 3 s., it is irradiated in 27 B.i transported again gravitationally to the counter in 3 s., measured 1A 27 s. and finally gravitationally transported to a lead screened box. The labo- ratory electronics presented in Pig.2,a Multichannel Analyser (MOA) Nuclear Data, a PDP-8 computer and an electronic module controller - control the entire opera- tion* The MOA is working in the HOS mode (Multichannel Scaling Experiment)! In one channel the charge information is stored, and in the nejtt channel the gamma- ray intensity indicator* The electronic module controller acts on the mechanical transport system for the samples and also on the beam pulsing chopper (27 s. ir- radiation, 33 s. pause for the measurement and sample transport - see Fig*3> After irradiation, the sample is transported to a scintillation counter with a 10*16 cm diameter x 10*16 cm thick Nal(Tl) crystal* The counter la shiel- ded toward the sample by a 25 mm lead layer in order to reduoe dead time losses from the high 0*511 MeV gamma-ray activity* Finally* the PDP-8 computer calculates the ratio of the number of gBJuw- ray counts and of the integrated beam oharge and multiplies the result by a pre- determined normalizing faotor (the total protein oontent of a grain standard; to obtain the total protein oontent of the sample* This result is typed out. RESULTS AND DISCUSSION Several thousands of samples (wheat, corn, barley, bean and soya-bean) have been analysed with this nuolear method* Good odfcelation has been obtained be - tween the results of the Kjeldahl method and our nuolear determinations for sam- ples of various cereal grains (see Vig*4). A problem is the analysis of the whole protein region in a seed. Thus, for wheat and barley seeds the region of maximum protein concentration is 0*2 - 0*6 mm in depth /l#2,3/j in corn and soya-bean seeds this region is thicker (0*2 - 2 mm)* The effective irradiated and analysed mass is about 0*2 g/cnr (1*2 - 1*4 mm), very suitable for wheat and barley* To realise an acourate measurement for corn and aoya-bean, flour should be used to obtain a protein homogeneous sample* In this oase, the irradiation dose for a sample is about 33.000 Qy, mainly (99 per oent) from protons (27 s x 100 nA x 14 MeV). Thus, the radiation damage 38 Is conoentrated in a layer of 1.7 -2 mm under the irradiated surface of the seeds. By protecting the embryo region during irradiation, by the help of a suitable geometry of the samples the future germination of the analysed seeds will be quite normal (70 - 90 per cent normal seedlings) /V. This is the most important advantage of the present method. EBFEBINOES /I/ D.M. QrodzinBki, O.I1. Hemets, A.ff. llelenevski. Y.A. Tihi , Vestnik selskohozlaistvenol nauki, 7 (198?) 47 /2/ D.I. Dohan, E.G. Standing, Physics in Industry. Pergamon Press. Oxford and New Tork, 1976, 509. /3/ B. Sundqviat, L. Goenczl, I. Koersner, E. Bergman, IT. Lindh, Ion Beam Surface Analysis, Plenum Press, New Tork and London, 1976, 945 /4/ Gh. Dumitru, Ph. D. Thesis, Polyteohnioal Institute, Bucharest, 1983. FIGURES Fig.l. - Outline of the mechanized system for the analysis. Fig.2. - Experimental eleotroniosi 1 - Nal(Tl) scintillation oounter 2 - eleotronio ourrent integrator 3 - high-voltage supply 4 - linear amplifier 5,6 - single-ohannel analyser 7 - sealer 8 - eleotronio module controller 9 - SOB module 10 - multichannel analyser A - Control pulse for relays R^ and E, B - Gate pulse for the gamma-say measurement system 0 - Oontrol pulse for relays Eg and E^ D - Gate pulse for beam-pulsing ohopper (close) 1 - Gate pulse for beam-pulsing chopper (open) F - lfOS advance of MOA G - start of MOA H - digital pulse from the ourrent integrator or from the Nal(Tl) scintillation oounter Fig.3. - A typloal analysis sequence for a 60 s. cycle A,B,O,D,B,F - see Fig.2 Fig.4. - Comparison between the EJeldahl method results and our nuclear determinations. MAGAZINE IRRADIATION MEASUREMENT 39 H G 10 B A C A *5V- 3s 57S B +5V- 27s 30s !L 0 D 0 27s -6V 27s E F -3V |C T x -SOYA BEAN f -WHEAT AND BARLEY . - CORN O 20 40 60 80 100 120 140 160 180 200 220 240 260 NUCLEAR NITROGEN a.u. 40 be 8 090 w DETERMINATION OF IOUINE*129 CONTENT OF THIS PRIMARY COOLANT OF NUCLEAR POWER REACTORS I.Kuleff Faculty of Chemistry,University of Sofia,1126-Sofia,Bulgaria S.Zotachev SAEK"Kozloduy" - Scientific department,3320-Kozloduy,Bulgaria G.Stefanov Institute of Nuclear Research and Nuclear Energy,Uul.Lenin 72, 11,8**-Sofia, Bulgaria INTRODUCTION Iodine-129 is the only iodine radionuclide which exists in nature1 and is- obtained as a result of human activity-nuclear ..explosions and facilities aa well. As an uranium fission product (yield 1$) 3I is released in the envi- ronment notgQnly after accidents but at normal working conditions of nuclear reactors* ' X is among those radionuclideu,whose release into the environment from nuclear facilities plays an important gole in the global pollution of the biosphere due- ta its long half-life (1,7.10 y) and high radiobiologicalptoxity. In thia.respect the role of recovery plants in the pollution with f I is discussed ~ and its gontent has been determined in spent nuclear.fuel ' , waste waters and gases !' and in various environmental materials . The role of nuclear reactors in. I pollution is evaluated mainly theoretically from calculations of the I content in nuclear fuel or from prognostication of gaseous radioactive wastes .Besides verj often these evaluations are con- tradictory .The first known determination of °I in the coolant --of a nuclear reactor was done during and after the accident of TMI-2 in USA ' and the re- sults proved to be considerable lower than was expected. „ 17_2g The determination of yI in various materials,mainly biological ' 'Z » atmospheric air ' ,natural waters '''^ ..is carried out usually by KAA 9. In some cases direct X-ray spectrometry '|J as well as liquid scintilation spectrometry ' ' have been used.Better analytical parameters(lower limit of detection,accuracy) aire typical for NAA methods while direct X-ray spectromet- ry is more simple. The aim of the- present investigation was the development of a reliable neutron activation method for .1 determination in the coolant of nuclear power reactors,since its content there is the basic factor,determining the release of ' I in the environment at normal work of nuclear reactors. The use of the proposed neutron activation method and X-ray spectrometry are discussed In the paper aa well. EXPERIMENTAL A. Iodine—129 isolation •j •» V. 3 cm 0.1. M KI are added to 1,000 cm cooling water as a carrier .The,, so- lution is made alkaline(pH 8-3.5) with several drops 2M (NH. )2C0,. and 5 cnr 2.5$ NaiOCl are added.After addition of 5 cmJ2 M NH^OH.HCl the solution is carefully shaken* „ 2. The elemental iodine,thus formed is trice extracted with 20 cm CCl^. The violet coloured fraction is gathered in a separatory funnel. 3. 20 cnr distilled water and several drops 1 M Li SO,.6H 0 are added to the funnel.It is carefully shaken until both phases become colourless.CCl^ is discarded. .. „ k. 1 cm conc.HNO- and 1, cm 1i M NaNO are added to the water phase and step 2 is repeated. 5. Repeat step 3. 6. 2 cm 0.1 M Ba(N0_)2 is added to the solution and the residue,thus for- med is filtered and discarded. „ 7. The filtrate is acidified with several drops 2M CM C00H,2 cm-1 0.1 M O^)^ are 129 At the same time the I content in the coolant is below the detection limit of direct X-ray spectroraetry,reached at our conditions. 129 Table 1.Conten.Content of I in the cooling water of the reactors WWR-44O in nuclear power station "Kozloduy Method Number of Content (mBq 129I/dm'') Ratio 129^7131j determinations NAA. 5 17 T.5 2.5.10"8 X-ray a spectro- 5 110 16.2.10 metry The data in Table I are 2*»0 times lower than the data for boiling reactors. and 10 times lower than those for Pressure reactora*calculated theoretically . On the basis of the result for yI,the ratio yl/ J I was experimentally determined for the cooling water of nuclear reactors, type WWR-MO.The result given in Table-1. is twice higher from that in Ref. and lower than the value iven in Ref. J for pressure reactors(4.6.V0->tiroes) ,and for boiling reactors ?4.6.10 times). 129 .... Using tne result for 1/ I ratio in Table I and assuming the radioiodi- ne content in the cooling water as a basic factor for its emission in the envi- ronment for a 10 years exploitation periodgof the nuclear power station "Kozloduy" .We used the data given in Ref. for the eight years period( 198i)and our results for 1982 and 1983 for the quantities of I released to the environment from the reactors of nuclear power station "Kozloduy".The total quantity I emmitted to the environment during the 10 years period amounted to 106a Bq which amounts to 44*3 Dq mean disposal per year.If we calculate the total quantiti of emitted I to the total quantiti of electric power,produced at nuclear power station "Kozloduy" this means 140.tnQaZMWgCoraparad to the data about the emission of "i from recovery plants >f •>*JftJ ,these values are extremely small. CONCLUSION The neutron activation.methodproposed in the present work,permits the reliable determination of lz"l in the cooling water of nuclear power reactors. The lower limit of detection amounts to 2.9 mBq/dnr and the precision-to 9 #>. Our Investigations proved that direct X-ray spectrometry is not suitable for these purposes. tne Results were obtained for iodine-129 content in the cooling water of 2q first cycle of nuclear reactors type WWR-44O.On this basis the quantity of I emitted to the environment at normal, working conditions was calculated and experimentally the neglegible participation of the nuclear reactors in the global pollution of the biosphere with iodine-129 was proved. REFERENCES 1. H.R.Von Gunten.ActinideB Rev., t(l969)275. 2. R.R.Edwards*Science,t37(1962)85*. 3 E.C.Alexander,B.Srinivasan,0.K.Mannuel,Earth planet Sci.Lett.,5(t969) HIUTHOH AOTIVATIOH AKALTSI3 OF 80MB HIGH PUHITI SUBSTAHGB8 Maria S&lagean, Ana Fantelloa Institute for Physios and Nuolear Sngineering Bucharest lfQ~6, Boaanie Oornelia Dan, Ilena Apostol Institute for Physios and Technology of Materials Bucharest MG-6, Bomania Abstract! 0aI2, Ge02, BigQ, and (HH^gltoO^HgO of high purity have been analysed by IHAA. Trace elements Ag, Au, As, Br, Oo, Os, Fe, Ha, Bb, Sb, Sc, Sr, Zn at ppm and ppb level were determined. IHTBGDUOTIGn It is Important to know the trace element contents in some samples in or- der to get high purity materials needed by various domains of resaaxch and technology. Impurity levels of 1-50 ppm are considered for these substances. The first three of above analysed substances were obtained in the Institute for physios and Technology of Materials. OaFo is used in growing crystal prooesses. These crystals have applica- tions in many domains of optlos (infrared instrumentation windows for gas - analyser, LA81B media, etc). GeO and BloO, of high purity were prepared to be utilised in the process of groowinl2 g 6 BIoOx.GeCu crystal_ s with piezoelectric properties and also 2 2U0,,i GeOu having feointiliation properties. (BHt^MoOi,.* HoO of^high purity was analysed since It is used as a reac- tive <*gent in the trace analysis of F and Si. It is also used in obtaining lead molibdatum of which piezoeleotrio crystals are grown. The powder samples (30 mg in weight) packed in aluminum foils were irra- diated for 26 hours in a 1.4xlO*>3n/amZ.B. flux. Soil-? and Au (0.105 ug) were used as standards* The samples were transfered after irradiation in clean vials to be measured. The measurements of 3-5 hours were performed using a Qe(Li) deteotor proteoted by lead after 5t 19« 40 days oooling time. Fragments of the gamma spectra registered for the analysed substances are shown in fi- gures 1, 2, 3, 4. The traoe elements found are Au, Ag, As, Br, Oo, Os, Fe, Ha, Eb, Sb. So, Br, Zb. The background contribution in the Oo determination was taken into aooount. ES3DLTS AHD DIB0US8IQN The concentration valuea of the investigated trace elements are presented in table 1. TABU I Oonoantration (pPm) 0aF2 GeO2 Bi2Oj (11^)^00^.4^0 Au(ppb) - 0.9+0.2 - - AS - 0.05+0.01 - - As - •M 0.12+0,02 - Br - - 0.10+0.03 - Oo(ppb) 1.8±1.0 0.9+0.6 0.5±0.3 7+2 Os(ppb) - 2±1 - 470+30 Fe <2 1.9+0.6 1.1+0.6 <2 Ha - 19+2 0.5+0.2 - Bb - - - 2.4+0.3 Sb - - - 0.10+0.02 Bo(ppb) - 0.15±0.06 - - Sr 843 - - - Zn 0.04+0.03 0.04+0.02 0.4+0.1 45 Sh« low ierel of the impurities content reflects purity of tba ^malns above ENERGY (keV) Figure 1 ENERGY (keV) Figure 2 COUNTS / CHANNEL COUNTS/CHANNEL 99 739 Mo 511 — 765 95Nb(Mo) 609 (Bkg) -559 76As — 619 82Br .913 92mNb(Mo) 92mNblMo) 777 m m z z 205 91mNb(Mo) m m TO Q 82 o Br JT n> < 1173 60Co U60 bkg W o o X ro O 1692 U60 [Bkg) $9-85001 bf 47 14-MeV NEUTRON ACTIVATION ANALYSIS FOR OXYGEN DETERMINATION IN SILICON SINGLE-CRYSTALS Timus D.M., Gala^anu V., Oatana D. Institute for Physios and Technology of Radiation Devices Bucharest MG-6, Romania Blaga N., Popesou 0* R-D Institute for Electronic Components Bucharest, Romania Bradeanu A* Radio Components and Semiconductor Entreprise Bucharest, Romania INTRODUCTION In the processing of the semiconductor devices, a frequently ocoining problem is that of the oxygen oontent In silicon single-crystals. Silicon be- haviour is strongly affected by the concentration, spatial distribution and state of the oxygen in the orystal volume* Using infrared absorbtion method, Oshawa et al. /I/ have reported that helical damages are generated in the high oxygen content domains* Currently used methods for the oxygen content determination are destruo- tive (emission spectroBoopy) or limited to the interstitial oxygen atoms (in- frared absorbtion)* The present work deals with the application of the nondestructive, fast neutron activation method for the total oxygen oontent determination with re- gards to the correlation of this content with the material properties of the silicon. PRINCIPLES 07 THE FAST NEUTRON ANALYSIS The method applied is based on the study of the nuclear aotivation reac- tions induced by fast neutrons in their interaction with the nuolei of the chemical elements* If the sample to be analysed is irradiated in a beam of particles, the induced radioactivity of the isotope has the following time dependent varia- tion i f 6..Q2.1O2? a Avogadro's number M,m a atomic mass, respectively mass of the chemical element, whose isotope is activated 8 a isotopic natural abundanoe ratio of the activated isotope (%) mean density of the flux in the investigated speoiaent(oBrZ8"i) t oross-seotion of the activation reaotion (am?) * radioactive constant of the produced radioisotope (cm-1) T1/2 m half-life of the induced radio isotope t, a irradiation time (the same units as I^) •Che decay of the aotivated radioisotope is accompanied by the radiations whose energy and time evolution are characteristic to the initial activated element and independent c\ his physioo-ohemioal state* For the oxygen deterioration by aotivation, a large number of nuclear reactions oan be used in principle /2-4/v from which that based on fast neu- trons i* the most important. For neutron energies Bn> 10 MeV, the following reaotion is producedt Bra6,13 MeV, 7,12 MeV 16 p jr > 16O T / 74 with energic gamma ray emission. By interpretation of the informations provided by the gamma radiation specifics to oxygen aotivation, the total oxygen oontent m in silicon can be determined using equation (1), taking into account that (Tn,pfM-.10<>^6cm2 16 (for Bnal4 MeV) and benefiting by the high value of 0 abundance ratio (e = 99,76 $). Reaction (2) offers the following advantages! a. The irradiation and measurin g16 times can be short, because of the short half-life (T1/9a7,4a) of the isotope N produced. Analysis is rapid. b. Gamma'rays emitted by the 16N have energies (6,13 MeV;7,12 MeV) higher that of the others elements. Since the energetic discrimination is possible, the analysis ia specific. o. High neutron and gamma rays penetration, determined by the characte- ristic energies, allows to analyse great volumes. Analysts is representative. d. Rather high cross-section. Analysis is sensitive. e. Irradiated sample is not physico-ohemioally modified. Analysis is non- destructive* f• Fast neutron flux densities of (108-109)n.cm~2.s-l. can be obtained by means of a low voltage direct accelerator type fast neutron generator. In order to avoid the possible errors Induced by the difficulties appear ring in determination of the neutron field parameters (£,0",ti) from relation (1) /5»6/, we have prefered a relative method with a standard of known oxygen content (AlgO*, quartz, etc). APPARATUS AMD EXPERIMENTAL PROCEDURE The equipment and experimental set-up of the analytical system contain the following partst a. Fast neutron generator 14-MeV monoenergetio neutrons are produced in the following nuclear fu- sion reaction, by bbabarding a tritium occluded target by deutons with an e- nergy of about 150 keV in our GOT type GEHBDAO neutron generators H> + a. » a + 4H« (3) Deutons are produoed by deuterium ionisation in an ion source with osci- lating electrons electrical discharge and axial magnetic plasma confinement. They are extracted from ion source and fooussed by means of an iono-optic lens. Thus formed deuton beam is thehaooelerated in a single gap tube up to a potential of 150 KV, accelerating potential being supplied by a voltage multiplier self contained in the direct accelerator. The intensity of the de- uton beam can be controlled up to 1 mA by controlling iono-optic parameters of the accelerator. The target end of the accelerator tube can be radiated from the main unit by means of a valve, which allows rapidly replacing of the target, without breaking the vacuum in the rest of the accelerator. The tar- get is situated at ground potential and water-cooled. A mobile tantalum screen pneumatically positioned in front of the tritium target intercept the deuton beam in order to spare the tritium and to correlate the sequences of the ana- lysis cycle. The neutron production obtained for a deuton beam intensity of 0,5 mA, is about lOiOn.s"1 in 4TT solid angle. All the functional parameters of the neutron generator are controlled from the control panel* b. Counting and control equipment Gamma ray counting system is composed of two identical units i one for the sample to be analysed and the other for the standard. They contain a gamma scintillation detector (Nal orystal), a photomultiplier, a preamplifier, a li- near amplifier with variable energy discrimination thresholds and a counting scale* Background noise is automatically corrected. Lower discriminator thres- hold is set at 4,5 MeV since no other isotope produced in the sample emits gamma-rays above 4 MeV. Oounts from both units, which are proportional to oxy- gen oontent, are fed to an electronio computer, where after gaemebloal and at- tenuation corrections, the oxygen oontent of the silicon single-crystal is calculated. Bleotronic equipment contain* also the units which control and operate the temporal sequenoes needed to the analysis oyole. The sucoesive operations were programmed according to a sequential oyole* The presence of the sample and of the standard at the measuring or at the irra- diation places, as well as the neutron generating state of the neutron genera- tor is indicated on the control board. The irradiation or measuring sequence starts only if the sample and the standard are in their required places* o* Pneumatic conveyor system Due to the short half-life of the 16H isotope it is essential to trans- port rapidly the sample and the standard from the irradiation site to the mea- suring site. A double rectangular section (internal dimensions 21x11 mm) alu- minium pneumatic transport system brings the samples to and from the irradia- tion site. The transit time is less than two seconds. Time dependent varia- 49 tions of the neutron flux density are without effect on the accuracy of the analysis. In order to avoid the mutual influence on the counts, at bhe measu- ring places, the two transport ducts are separated by a distance of aprox. 1 m. The pneumatic system for the sample has an automatic feeder for the in- troduction and ejection of the samples. The decay of the 1% nuclei is total after aproximatelly one minute, so that the standard can serve indefinitely for analysis* RESULT AND DISCUSSION Use of the relative method of analysis implies the knowledge of a correc- tion factor for the spatial flux density gradient, energy dependence of cross saotlon, neutron attenuation in the sample, facing the tritium target. la the x and s indices refer to the sample and the standard respectively and taking into account aquation (l)v the oxygen content has been calcu- lated according to the following relation! when E is determined by two standards with the same known oxygen content, ir- radiated and measured simultaneously* Samples (20 mm dia., 10 mm heght) cleaned to remove the surface contami- nations have been conteinarad for easy handling. Using the above mentioned equipment and experimental set-up, the total oxygen content has been determined in silicon single-crystals. Values from (lOQ*25)ppm to (180Qi90)ppm have been determined. They are one to two orders of magnitude higher than the interstitial oxygen content values, due to the annealing treatments applied to the silicon crystals as received* CONCLUSIONS 14—MeV neutron activation analysis of oxygen in silicon single-crystals is rapid .(total analysis time is less than 60s), specific (allows a good ener- getic discrimination In relation to other elements)and precise, being able to characterlaa nondastructlvely the whole volume of the analysed sample* HBFIHBN0E8 /I/ A. Ohsawa, K. Honda, S. Ohkawa, R* Veda. Appl.Phys.Lett.36,2(1980)147 /2/ R.Van Grieken, J. HoBte, BURIS0T0P-65,Bibliografies-8,1972 /?/ G* Brdtmann, Neutron Aotivation Tables, Verlag Ohemie, Welnhelm,1976 /V S. Godar, Note OBA No.2W-5» 1962 /5/ D.M.Tlmue, M.N.Tlmue, Bev.Roum.8ol.Teoh.-Bleotroteoh.et Inerg.,17,2(1972) 251 D.M.TlmuB, 7T-£2f-1983( IOBPIZ-Buohar«at, 1983. 50 INSXRUMENTAL PH0T0A0TIVATI0N ANALYSIS 07 BOMB ILBMENTS IN BTXSL V. (*&l&$anu, B. Timus, D. Oatana Institute for Physios and Technology of Radiation Davices Buoharest MG-6, Romania INTRODUCTION Photoactivation oan be successfally used for analytical purposes as a oompl«tua&*ry method to the neutron activation, especially for several low and medium. 1 elements in balk samples and when moderate sensitivities are n««d«d /1-3/. This is the oase for steel samples in which must be nondestructively de- termined the concentrations of some minor elements. The low absorption of activating high energy X-rays, the small cross sections and the unfavorable half-lives and gamma-rays energy of the photoac- tivated major elements offer the possibility to investigate large represen- tative samples. The main reaction an* speotroscopic data concerning the analysed elements are summarised in Table 1 /4/. TABLE 1. - Photoaotivation Data Analysed Nuclear T,/0 Main gamma-rays element reaction x/* B (keV (I %) Or 53Or ( i\p) 52V 3.76 m 1434.1 (100) Ni 58Ni (f ,n) 57Hi 36.0 h 1377.6 (78) Mo 92Ho (f ,n) 9lBMo 65 s 652.9 (48.1) }1508.0(24.2) INTSRPBHBNOBS The examination of special tables /5(6/ shows that no other gamma-rays with energies close to those listed in table 1 are expected to be produced through photonuolear reactions. The most dangerous interferences are due to other nuclear reactions pro- duo ing the same radioactive nuoleus as the useful photonuclear reaction. Two such interfering reactions are possible only in the case of Cr deter- mination i 5*V We have experimentally checked by irradiating and counting pure Mn and V samples that in our conditions none of these interfering reaotions oan be ob- served. BXPBRIMBNTAL PROCEDURE AND RBS0LT8 The disc sampleB (40 mm diameter and 3*5 mm thickness) were irradiated in the bremsstrahlung beam of a 25 MeV betatron, at OV5 m from the Ft target in order to insure a fairly uniform Irradiation. The gamma-rays were detected with a 40 am Ge(Ll) detector coupled to an IN 90 programmable analyser. For the determination of Ni concentrations, the irradiation, «cooling" and coun- ting times were 1 hour and the exposure dose was monitored with a transmission ionization chamber having an appropriate integrating time constant. For the determination of Or and Mo concentrations, the irradiation and oounting times were 5 minutes with a 0.5 min. transport time. The exposure dose was monitored by a simultaneous irradiation of pure Gr and Mo samples and oounting with a different speotrometrio chain. In order to perform quantitative analysis we prepared standard samples with known amounts from the analysed elements. Oorrection factors for selfab- sorption and solid angle have been experimentally determined by irradiating and counting steel samples with increasing thickness in front of the standard sample. The unknown concentration 0 of the analysed element is computed with the relation! 1 0,0- "„ , .-j m- . -IJ where 0' is the oonoentration of the investigated element in the standard 51 sample, m and m1 are the masses of the sample and the standard, I and I1 are the intensities of the gamma-rays used for detection and corrected for the selfabsorption and solid angle (the irradiation, cooling and counting times for the sample and standard are the same). The concentrations determined are between 0.1 and 9 % for Nl, between 0.4 and 18 % for Or and between 0.05 and 1.50 % for Mo, The accuracy of the determinations is 10 % for lower concen- trations and 3 % for higher concentrations. HISBRBHOES /I/ Oh. Sngelmann, J. Radioanal. Ohem. 55 (1980) 379 /2/ 7. Gal&tjanu, H. Greoescu, G. Baciu, St. Oero. Fiz. 26 (1974) 9 /3/ 7. Galafcanu, U. Grecesou, Rev. Bourn. Phys. 24 (1979) 9 /4/ O.M. Lederer, 7.S. Shirley, Table of Isotopes (1978) /5/ 7* Galafcanu, M. Greoescu, J. Radioanal. Ohem. 10 (1972) 315 /6/ Z. Banda, V. Kreisinger, J. Radioanal. Ohem. 77 (1983) 279. 52 APPLICATION OF THE IMAA TO THE INITIAL OS PROijCTILE LEAD o D.Dimitrov Institute of Criminalistic, Bul.Slivnitza 235, 1202 Sofia,Bulgaria INTRODUCTION Data having certain importance for identification of projectiles, causing gunshots, can be obtained on account of lead impurities concentration.This problem is discussed in a number of works (1,2,3,4), where the two methods of analyses are suggested - RNAA(2) and INAA [3,4).The proposed work rate (4J is of a particular interest because it is express.lt affords the opportunity for mea- suring the contents of Sb, Cu and Ag in a few minutes by using their short-life isotops Sb-124m1, Cu-66 and Ag-110.The samples are irradiated with reactor heat neutrons as the duration of each step (irradiation, cooling, measurement) is 40s.Gamma-lines 498keV of Sb-124m1, 658keV of Ag_iio and 1O39keV of Cu-66 are measured by spectrometer. The aim of this work i3 the creation of a sequence of operations in car- rying out the INAA of lead samples of proectiles, allowing the qualitative and quantitative initial comparison having in mind a single limitation - the time for the analysis of one sample must not exeed 20-24min. RESULTS AND DISCUSSIOM Some of neutron-activation characteristics of the chemical elements, found most frequently as lead impurities, are shown in (5,6).The intensities cf gamma- lines, measured after the irradiation..of the.corresponding chemical elements by slor-."l«i.wr reacto-MAnn4-Airn neutronYiaii4-»nnsa l.F-t+Vwithl flo"P1 r\Z.Tw no "fP 110'•'n O -'m. n cmm '.O s '-FlTT fo* r^D 60sc , Qar T» Oe 1 indicated.Usin Y1 ft 1 Cfl +. C*(\ . TT R T Tlg £f this work rate it is possible to determine micrograms of Sb, Cu, Ag and Au.The same applies to As as the As-76 has a half-life period of 2b.3h. The alteration limits of concentrations of the impurities in lead samples and some gamma-lines are shown in table 1(2,4).The expected initial intensities are calculated in accordance with[5,6). Table 1 - Range of concentra- tion values Range of consentra- Gamma-lines, Intensity, changes(2,4). •OJ.C1UCI1 U tion changes, ft keV c/s The real concentration Sb 0.05 -• 2.8 498.4 1.1.10"? values of the 602.7 1.1.10? impurities al- 645.8 1.1.105 low the instru- 2 2 mental record AB 1.10" -- 5.1O" 559.1 2.7-10^ of Sb, As, Cu 657.0 4.2.10^ and Ag only.The Cu 7.1O"4-- 5.1O"2 1039.4 1.8.104 close location 4 of 559.1keV of Ag 2.10" -- 8.10"5 632.9 1.9.1O4. 5 As-76 and 564.0 657.7 4.1.10 keV of Sb-122 Zn 1 10"4 910.0 1.10"1 gamma-linea, the 6 6 high contents of Au 1.10" -- 9.1O" 411.8 3.5 Sb and commensu- rability of half -life periods of Sb-122 and As-76 necessitates the analyses of Aa to be carried out on the 657.OkeV.The presence of As at the same is a problem concerning the Ag determination on the 657.7keV line of Ag-110. Table 2 illustrates the possible influence of As on the measurement ol Ag on the 657.7keV line of Ag-110.When the ratios between the quantities are as M = m(As)/m(Ag) fe.50 , the duration of the accurate measurement is limited to 0 - 30s immidiately after the irradiation.The defined conditions do not allow the start of measurement by use of a spectrometer earlier than 3O-4Os after tne irradiation.All this necessitates the determination of Ag on the 632.9keV line of Ag-108 and imposes the choice of irradiation durating 120-180s, cooling - above 200s, when the simultaneous measurement by a spectrometer of the 6>57.OfceV line of As-76 is also possible. The above considerations orientated us to the use of analysis scheme like that, shown on fig. 1. . The scheme is entirely carried out when the concentrations of As and Ag are commensurable.When M S* 50, the measurements are done according to the first part of the scheme. 53 Table 2 - Ratio of the intensities of lines 637.0keV of As-76 and 657.7keV of Ag-110 in percent.The calculations refer to the simulta- neous irradiation.^ of As and Ag with reactor heat neutrons with a flow of ~ 10 ?n.em .a . Goo- I r r a d i a t ion ling, s 30s 40s 60s 120s 180s M=50 M=1 M=50 M=200 M=50 M=1 M=50 M=1 M=50 000 0.5 0.01 0.6 2.2 0.7 0.02 1.2 0.04 1.7 030 1.2 0.03 1.3 5.3 1.6 0.06 2.8 0.08 4.0 040 _ 0.04 1.8 7.0 _ _ - - - 080 — 0.11 5.4 21.8 — - - - 120 15.2 0.34 17.0 68.0 — - - - 180 a3.o, 1.90 93.3, 373.4 116.2 , 3.93 196.6, 5.70 287.0, 300 2.5.10 556.4 3.10- 3.s.io5 119.0 6.1O3 173. 3 9.1° Samples from four real cases with mass between 120 and 180mg are analyzed. Cu-66(iO39.4keV), Ag-108 Cooking„ Measurement. (632.9keV), Sb-124m1(602.7 I. 210-2408 300-6O0e and 498.4keV), AB-76(657.0 keV) Irradiation. 120)-180- s Coolingt Measurement, As-76(657.OkeV) II. 500-840s 600s Big. 1 Table 3 shows the impurity coneentrations from Sb, As, Cu and Ag. Table 3 - Concentration values of Sb, As, Cu and Ag in the analysed lead samples from pro- ectiles, $. Samples Sb As Cu Ag The analyses are carried out by irradiation with reactor A 1.80 0.55 0.0013 0.001 heat neutrons, flowing at B 0.0008 0.67 0.0008 0.002 1 0.022 5.10 n.cm .8 and measure- C 0.33 0.0028 0.001 ment lay the use of Ge(Li) detec- D 0.091 0.02 0.0021 0.009 tor with efficiency 7.2 # arnd resolution 2.3keV on line In table 4 the values of the relative statistic deviations of results 1 Table 4 - Values of the relative statistic deviations at different analysis schemes, %. El e- Irradiation - Cooling - Measurement, s / Samples H6n."fc 120-210-300;120-420-300) 120-240-600;120-600-600;180-210-600 D A 0 A B D A B C Sb 3.4 1.1 15.6 0.6 0.5 - 7.5 As - 3.6 11.1 3.4 3.5 4.7 2.5 2.3 2.6 Cu 9.1 13.5 7.2 9.0 9.3 8.4 6.5 5.1 Ag 1.1 13.1 5.8 9.7 5.0 7.5 2.6 7.3 54 It must be noted that at Sb concentrations ^ 0.005 $ and at relatively high contents of As (samples B) an additional much longer irradiation and cooling are needed, so that the measurements can be carried out on gamma-li- nes 564.0keV and 692.5keV of Sb-122 or 6O2.6keV of Sb-124. COflCLUSIOJ!! A scheme for initial quantitative analyses of lead samples from proec- tiles, carried out by means of IflAA, is proposed.lt gives an opportunity for determination the concentrations of Sb, As, Cu and Ag when the contents of Sb are s> 0.005$.The analyses time consuming does not exceed 20 - 25 min. REFERENCES 1. P.A.VAGAHOV, V.B.IUKiriCHKI, Neutrons and Forensic Bcience, Izdat. Uni- versity of Leningrad, 1981. 2. R.D.GuT. B.D.PATE J. Radioanal. Ohem., 15(1973)155. 3. S.J.GAGE, J.B.WHITWORTH, J. Radioanal. Chem., 15(1973)337. 4. V.P.GUIHH, M.A.PURCELL, J. Radioanal. Chem., 39(1977)85. 5. R.DAMS, J. Radioanal. Chem., 61(1981)13. 6. S.A.LIS, PH.K.HOPKE, J.I.PASCHINY, J. Radioanal. Chem., 25(1975)303. 55 DETERMINATION OF Al, Cl, S AND V BY NONDESTRUCTIVE ACTIVATION ANALYSIS B.Smodis, L.Kosta, A.R.Byrne, M.Dermelj "J.Stefan" Institute and Faculty of Natural Sciences and Technology, "E.Kardelj" University, 61000 Ljubljana, Yugoslavia INTRODUCTION Neutron activation analysis of short-lived radionuclides by non-destructive or instru- mental gamma-ray-spectrometry (INAA) offers good possibilities for rapid and precise deter- mination of a wide range of elements in a broad spectrum of matrices HI. In the present con- tribution, the analysis of Al, Cl, S and V in a range of oils, rubbers, organic liquids, aqueous samples and inorganic solids is presented, together with a brief discussion of the factors affecting accuracy and precision, interferences, and the possibilities given by pre- or post-irradiation separations in certain cases. EXPERIMENTAL For the standard non-destructive procedure, the encapsulated sample together with a suit- able standard or standards were irradiated for periods of a few seconds to several minutes in the pneumatic transfer system (rabbit) of our TSIGA Mark II reactor at a flux of 4xl0l2n.cm~2 sec-1. The induced gamma activity was measured by an intrinsic Ge detector (17 % efficiency, 1.8 KeV resolution at 1.33 MeV) connected to a Canberra 80 Series MCA. For measurements last- ing half of a half life or less, with an initial dead tune of *slO %, a first order correction based on the mean dead time (given by the analyser) could be applied. For these high energy y -emitters, a Pb filter was with advantage placed between sample and detector to improve the signal to "noise" ratio. RESULTS AND DISCUSSION Aluminium 2? n 28 Al(100%) J ')^,,» Al(t, ._ = 2.31 nan, Ey = 1.778 MeV, I = 100%) The main interferences, apart from second order reaction from Mg, are fast neutron production of 28^ Via 28si(n,p) and 31p(n,o«) processes. However, the cross sections for these reactions are small, so care is needed only in matrices based on Si, P or Mg, with low Al levels. Corrections based on estimation of the fast neutron contribution using Cd covers to screen thermal (n,y) reactions were not required for the matrices studied. Al was determined in rubber, motor oils and oil filters, and in TiO2. (In the latter case use of a thick Pb filter improved the signal/noise ratio by around a factor of 103). Concentrations from 0.1 to 1500 ug/g were measured. Chlorine 37 n r 38 C1(24.2%) i ' n k?h» Cl(t1/P = 37-2 nan, Erl = 1.642 MeV, I = 33%, c = 043b 1/2 ' 6 m% Interferences may arise from second order reaction on 36s( Or fast neutron reactions via 38Ar(nFp) and 4lK(nlOe). Again these cross sections are small so that appreciable errors arise only in matrices based on argon, potassium or sulphur. Samples analysed included water, steel, corrosion products, welding tape, and various industrial products. The concentrations covered the range 0.4 to 1000 fJg.g"1. Results were verified by gravi- metry in some cases (AgCl). Where high 5BMn activities were induced in certain metal products, distillation separation of 38ci after irradiation was necessary. Sulphur 36 ( 37 S(O.O15%) tf "'^15g S(t1/2 = 5.06 rain, Ey= 3.10 MeV, I = 90%) Because of the high Er, (only ^Ca, 3.08 MeV, has a gamma ray in this upper region), selectivity is high; on the other hand, sensitivity is poor (low abundance, small*). The only practical interference is via 37ci(n,p)37s. Measurement of 3°ci to determine the S/Cl ratio is required and a correction is applied if necessary. In oil products and rubber, Cl/S ratios are not of significance and results m the range 0.5 - 4 % and 0.7 - 2.5%, respecti- vely, were obtained. Results were verified by gravimetry (BaSOij) after oxygen ignition, and from some results obtained with ASTM mfethods supplied by the refinery for oil products. (Table 1). Table 1 Comparative results for S and V 1 Sulphur (ir i %) Vanadium Uig.g- ) Sample INAA gravimetric refinery INAA refinery Heavy oil 1 3.,53*0.14 (4) 3-53*0. 05 (6) 72.9, 67-1 Heavy oil 2 2.,76±O.O5 (4) 2. 81*0.04 (6) 51.0, 50.9 Heavy oil 3 2.,74*0.04 (4) 2.74*0. 11 (4) 41.3, 40.9 Heavy oil 4 2.,63*0.08 (4) 2.66±O.11 (4) 50.6, 49.4 Heavy oil 5 3,.12*0.18 (6) 3.2X 82.6*1.5 (6) Light heating oil 0,.72-0.03 (3) 0.103, 0.097 Benzene 0.048*0.004 (4) 0.001, 0.0014 determined by gravimetric standard method ASTM-D 1551 xxdetermined by colorimetric standard method ASTM-D 1548 Vanadium 51V (n,y)t 52V {t . 3>?5 mini EY= 1-4314 MeV( : . 100%) Interference reactions can be ignored at concentrations of V in the ug/g range and above, where INAA is applicable. V was determined in oils, rubbers (see Table 1) and Ti02 pigments. In the latter, a Pb filter is very advantageous.However, if the Al/V ratio is greater than about 100, determination is very difficult or impossible, and pre-separation becomes the best option. Further results will be presented in the full paper. It can be concluded that, provi- ded interferences are controlled, determination of Al, Cl, S and V in a wide range of indu- strial and other products by INAA represents an attractive, and rapid alternative to other analytical methods. REFERENCES 111 Nondestructive Activation Analysis, S.Amiel (Ed), Studies in Anal.Chem. No.3, Elsevier, 1981. 5 9- 8 DETERMINATION OF PLATINUM CONCENTRATION IN GOLD MATRIX BY NEUTRON ACTIVATION V.Cojeearu, Stefania Spiridon Institute of Physics and Nuclear Engineering, P.O.Box MG-6 MBgurele-Bucharaat, 76900, Ramania INTRODUCTION The determination of platinum concentration in a saaple with a high amount of gold is a difficult problem. Eren more difficult is to finde the platinum concen- tration in a gold matrix. Nevertheless the problem is important at least in ar- chaeology and geochemistry investigations. Platinum has six stable isotopes, all of them having moderate values of the neutron activation cross section. One hour irradiation of platinum in a reactor gives for th« stable isotopes ^Ojpt, 192p+ 194pt, 196pt and 198pt a production factor of 0.07, 0.05, 0.08, 5.0 and 100.0 re- spectively. The only nuclei which deserve to pay attention are the last two. 197pt is not very convenient having the most intensive gama-line at 77.46 keV (21 %} that is in the X-ray region and a relatively short half-life (18.5 h). The most productive is1 99pt with a short half-life (30.8 min) and not very intensive gemma-lines (542.7 keV has 16.4 *), but it is B"-decaying in 199Au (TJ/2 = 5.13 d). This seems to be a good alternative. Unfortunately in neutron irradia- tion !99AU is also coming on the other way (Figure 1). i , ** I Figure 1 197 Au Jn.iL 198 Au Ml, 199 Au The idea of the work consists in the pre-irradiation separation aB far as pessible of platinum of its matrix and to find the most favorable irradiation con- ditiona of the separate sample in order to get a high ratio of activities A199/ A199 were by prime is indicated the interference ehain initiated by !97AU. EXPERIMENTAL Chemical separation. The pre-irradiation separation was made by means of nany step organic solvent extraction technique, followed by ion exchange procedure* The tests wsre made with gold and platinum metals irradiated at the neutron fluxes in such a way to create balanced activity tracers 198±u ftnd 199pt (or 197pt). After irradiation the samples were mixed up, completely dissolved in aqua regia and sep- arated. Counting was done using a 50 cmc coaxial Qe(Li) detector and a 4096 channel pulse-hight analyzer. System resolution is better than 2 keV fwhm at 1.55 MeV TT- ray. The detector was placed in a low background protection which reduces the background around 100 times. In order to keep a constant geometry all samples were measured at the sama volume (12 ml). The separation scheme is summarized graphical- ly in Figure 2. The solvent extraction was repeated four timee. The aqueous phase of the fourth extraction was heated to dryness and the residue was- dissolved in 3 ml of 3N HC1. The solution was then passed through a Bmall (0.5 cm diameter) column with 0.25 g Dowex 2 x 10 (200 - 400 mesh) ion exchange resin at a flow of 12 dropB/min and washed with 50 - 125 ml solution of HC1 cone.(10 %) + acetone (90 %) at the same flow rate. If the initial ratio Pt/Au = 1, after the first and fourth solvent extraction steps it becomes in aqueous phase. 200 and 4000 respectively. In this time the platinum concentration is reduced to 80 %. After the ion exchange procedure the ratio becomes Pt/Au • 105 and the total recovery of platinum iB found to be (68 - 3) %. 58 Sample | Disolve in HNO3-HCI Make 3N inHCl (7.5ml) Extract with ethyl acetate (2.5ml) I oqueous (Pt) — f-t-y) Heat to dryness ^-""^ Disolve in HCI 3N(7.5ml) Extract with ethyl acetate (25ml) Repeat U times aqueous (Pt)—( Heat to dryness Make 3N in HCI (3ml) * Dowex 2»10 brojHCl cone. (10%i (200 - A 00 mesh) P*9 acetone (90%) (50 - 125ml! eluent resme- Figure 2 Irradiation parameters. The irradiation tine and the neutron flux have to be properly chosen in order to Bake the ratio of the !99AU activity cosing from plati- num (A199) to the J-99AU activity coming from gold (^199) as high as possible. One can find that at the end of neutron irradiation (see Fig.l): 9 Im these equations where I is the integral resonance. The ratio M99/ A199 vs. the irradiation time ie given in Figure J. The eurves 1, 2 and 5 are ealoulaTed for a flux of lOll, id* and 1OW n em-2 a-1, re- speetiveiy. The lower neutron flux the higher the ratio A190/ A199,but a too low flux can give an insufficient detection limit for platinum. For a necessary fluence it is better to chose a lower neutron flux. At the gamma-spectrometeruaed in this work the detection limit is of 55 ng Pt far an irradiation time of 5 h «nd a meas- •uring time of 1O0OO a. With a reduction of gold concentration by 105 times and a A/A = 8, an ameuat of 5 mg gold will give a correction of only 10 % in the r~ lime of 158.4 keV (199AU). Thia correction ie found by aid of the ratio (area of 158.4 keV «*-iiBt)/(area of 411.8 y-line) of a standard of gold irradiated in re- actor together with the investigated samples. RESULTS AND DISCUSSION Nuggets of geld from different plaoers of the Apuseni Mountains (Romania) and frem Romanian rivers j^ave been used aa samples. The mass «f the eampleB was between ' "^Im ardor to ebaerva by aid of 198AU tracer the reduetien ef geld alamg the platimom separatiem process the samples ware irradiated at a low meutrem fluemee 59 (6.101' m «»~2). The recovery af platinum waa feund uaing a combination of plati- num and geld with a mass ratio Pt/Au «^ 1/1000 which waa preeeos*d ia tha same way with tha investigated samples. Tha reaiaa am whiah platinum waa retained were irradiated a tine of 20 haura at a tharaal neutron flux of 1.1 1011 a ««-2 a-1 (thermal column of the WR-S reactor). \ 8 1 / \ f \ 2 Sj \ r - o I / at f 1 \ r3 -1 / f r \ ••^iBHi -21 J 1 01234 5678 log tjr (sec) Figure 3 counting waa dana after a decaying time af 6 daya in ardar ta gat a law 2*Na aad aetivitiea earning fram realn. Conoeatratioma af platinum between 0 and 460 ppppm with an areregegee af 2700 ppmm were faund inn tthe inveatigatanveatigad nuggetsnuggt. ItInterferef d to. TThhaa interferencitferencinterfeencee af 47ssee (159.(59444 keVe)) eoming fram46ca(aa ((ir)47C() a (p) ia not poapaibleaiblei , ealeiuli mm beinbi g nott retineretainetidd by tthaha rraaina i . AlaAla o ttheh e rreactienti e (n,p)) aanndd ((n,<(,^ ^ ) whichiichh poproducd ee **7s7scc aree excluded ainea thermall nautran fluxeaa wawarre uaed. NaTortheleeB tin by thell7"Sll7 n (1( 4 d) iaatapi e whiai h haa only a /-lini e (198.(1 4 kaV) aan interfere with 199A.tt. Ita preaence can be put in aTidenee ceunting either 158.4 kaV tf-line after tha decay af 199A« (ea. 90 d) or 992 keV tf-iina af tha I1"Sm (119 d) iaetepa and doing tha neeeaaary eerreetiene. A tin standard was irra- diated together with the raaina en which platinum wae absorbed in order to find the ratio of the areas *(198.4 keV)/*(929 keV) coming from tin. In our samples no tin interferences waa found. 60 5 IMPURITY Dfc TERMINATION IN Bi.,0 ANJ) Jlg BY NliUTHON ACTIVAFIuN ANALYSIS AND ATCMIC ABSORPTION SPECTROMETRY S.Aleitsandrov,I.Kul«ff .R.Djingova,S.Arpadjan Faculty of Chemistry, University of Sofia, 1126-Sofia,Bulgaria: E.Taakaev Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, 118^-Sofia, Bulgaria INTRODUCTION Lately the interest in the production of monocrystals and optical fibres from inorganic materials grew immensly because of their importance in lazer technique and optical electronics. A very important condition in production and use is the purity of the raw material. In order to evaluate the properties of the high purity materials, used nowadays in different branches of electronics one must use highly sensitive analytical methods. In the present paper are presented some results from the analysis of high purity B12O., and PbCl™ obtained by NAA and AAS in the Analytical Chemistry Department of the Faculty of Chemistry. EXPERIMENTAL A.Neutron activation analysis. I. Preparation of samples and standards. About 0.5 - 1 g from the mate- rial is sealed in polyethylene container (for the first irradiation) or in poly- etiiylene foil (for the second irradiation). (The polyethylene foil has been ootained under high pressure. The two materials are before washed with detergent and water, put for Z-* h in HNO (i:i), washed abundantly with deionized water, aha alcohole and dried under IR lamp.) As standard IAJUA reference material V-9 (cotton cellulose) is used /i/. Additionally well Known quantities of Ag and As are added to it since in V-9 tnose two elements are in lower concentrations than in the samples. The standard is sealed in the same way as the samples (about 0.1 g). 2.Scheme of the analysis. The scheme of the analysis is shown on Fig.l. The radionuclides and gamma-lines used in the analysis are given in Table 1. The first irradiation is done using the rabbit system of the experimental nuclear reactor tM-300« Al.Co.Ce, Cu.Mg.Mn IRT-2000, Sofia /z/ with a neutron flux 6.10 em .s . The second tM-5000i As,Au,Br,Hg, irradiation was performed in one K,Lo,Na,Sb of the vertical channels of the reactor with neutron flux amounting 1i2 2 to (i-3).1.0 cn.- .B-\ tw-1Q0Q0» Ag,Ce,Co,Cr. After the first irradiation Fe,H(,Zn,Zr the gamma-spectrometry of the samples^aone on a Ge( Li) detector (energy resolution 2.8 KeV, efficiency 8 i for H332.5 KeV) Fig. 1 Scheme of INAA of Bi 0_. connected to a kO96 channel analy- t =irradiation time}t =cooling zer Canberra kO, after the second fl o irradiation the measurements are tlme;tM= measurement time. done with a 6e( Li) detector (ener- , ,, . ,,.,„, , BY resolution 2.3 KeV, efficiency 1<+ > at KJJ2.5 KeV) connected to 4096 channel analyzer Canberra 31.80. It should be mentioned that the measuring time for the samples of PbCl- was twice longer than that for Bi^O (shown on Fig.l). * The data evaluation (including all necessary corrections)was done by using a program according the algorithm, described in /3/. B.Atomic absorption spectrometry. The determination of Cu.Fe.Ni, Cd, Zn in PbCl., ls done after concentration of the elements by using a three phase extraction with MIBK /k/. The determination of Mn is performed after acidic extraction with H_S0K. The samples of Big03 are dissolved in 8 M HC1. After extraction with MIBK 61 Fe and. Mo are determined in the organic phase by the standard addition method. Cu,M,CoiCd,Pb and Mn are determined after concentration, transformation of fli.O.into ai(OTK)~ and three phase extraction with MIBK. The elements pass into tne organic phase, which is directly pulverized in flame air/acetylene. Tne standard addition method is used. All measurements are done on AAS Pye Unicam SP 9. RiSULTS AND DISCUSSION Table I, together with some parameters used in the NAA of BigO.. and FbClg contains the detection limits reached by the analysis. In most cases NAA is sensitive enough to give reliable result?. But where due to matrice effects or apeciiity of elements, it is not sensitive enough then AAS comes to the purpose, so the combination of the two methods proves very successful. One of the most serious problems ift the INAA of high purity materials is the purity of the packing material used for irradiation. In the analysis of BipO_ and PbCl., the repacking of the samples after irradiation is not possible since due to the radiation field in the active zone of the reactor the samples partially are destructed and as a result of this a new component is formed - elementary Bi and Pb. We used polyethylene as packing material which proved to be very suitable but it demands irradiation with lower fluxes. This choice was done not only because of its purity but because it permitted the determination of Al in Bi^O~, because of the interference nuclear reaction Si-28(n,p)Al-28 whicii takes place in quartz. It should be mentioned that in PbC^ due to the high matrice activity (Cl- J6) , Al, Oa.Cu and Mg cannot be determined by NAA. So the short irradiation (Fig.!) in the analysis of PbClg practically brings information jonly for Mn. The combination with AAS permits in thia case not only the determination of some of the mentioned elements but because Mn is also determined by AAS the snort irradiation in some cases may be omitted. Tiie results from the NAA and AAS of Bi2O» and PbCl are presented in Tab- le 2. Tne combineduse of both methods permits the determination of more than 20 elements and among them as such for which INAA is not sensitive enough ( Pb, Ni,Cd,Mo). Additionally this approach enabled to control the accuracy of the method by comparison of the obtained results from the two methods (Co,Cu,Fe,Mn, Zn) . This is very useful, since standard refernce materials for the analysis of high purity materials are not available. Among the elements in Table 2 there are some whose content is usually not normalized by the user. They were however determined mainly to demonstrate the possibilities of the combined use of NAA and AAS. At the same time they enable the producer to critically evaluate some technological steps /5/ as well as to meet, some specific requirements of different users. REFERENCES /I/ L.Pszonicki, A.N.Hanna, O.Suschny, Rep.IASA/RL/97 ( 1>983) . /2/ D.Apostolov, Nuclear Energy (Sofia), 5 (1976) 109. /}/ V.Dianovitch.D.Todorovsky.R.Djingova,I.Kuleff.Y.Yanev,J.Radioanal.Chem., 6J ( 1*81) 13. S.Arpadjon, A.Kojnarska, tt.Djingova, Fresenius Z.Anal.Chem., (in press). G.Giulmezova, Proc.Nat.Youth School "New Technology and Materials", Primorsko, 19dk (in press;. Table 1. iiadionuclides and gamma-lines Table 2. Hesults from IhAA and used by INAA.Detection limits AAS of Bi,0, and PbClo reached by the analysi s . 1 J c Ele- Radio- Gamma- JDetection limit (ng/g) Ele- Concentration (ng/g) HiiA 1 J/lA ment nucliuv xxne * Bt2°i PbCl2 in cut Bi2°3 PbCl2 Ag Ag- 1.10m 6 4 ± 657.7 Ag ^3 560 50 Al Al-28 1.778.8 12 N.D. Al i4oo - too N.D. As As-76 559.1. 1i. 1i 6.8 As 270 ± 30 23000 t5000 Au Au-1.98 411..8 0.9 0.01 Au 3.9 ±1.6 0.9 40.3 Ba Ba-l^l 496.3 4500 N.D. Ba ^5500 N.D. Br Br-82 776.5 0.6 19 Br 7*2 11*3 Oa Ca-49 3084.4 400 N.D. Ca <400 N.D. Od „ _ 15* 15' cd 35J2* 53 t 3" Ce Ce-t4t 145.5 0.6 0.5 Ce 15-3 2.1*0.4 Co-60 1332.5 0.07 0.06 0.1.4 - 0.04 0.85 * 0.12 Co 6* 6* Co Or Cr-51 320.1i 2 2 Cr 47 * 5 38 i 6 Cu-66 1039.0 80 N.D. < 80 N.D. Ou _ - 15* 15* uu 62* 3* 72 t 3* Pe Fe-59 129H.6 34 30 503* 120 11430 t 570 ' - - 125* 1.25* 500 t 25* 1i32Ot 160* lie He-197 $8.8 N.D. 0.6 He - 260 ± 90 K K-42 V524.7 1.1,00 1700 K 2900 t 1400 107000 * 20000 af Hf-162 482.2 3 N.D. La 1300 t 50 »9 i 3 L.a La- 1i4o 0,2 0.2 Mg -i 1500 N.D. Mg Mg-27 1l 0 T4 r ^ 97 N.D Mn 4 t 2^ 28 ± 5 Mn-56 Id11.2 0.06 5 _ *• 1.0 <1,60* MH. - 1.0* 1.60* Mo *: 500* N.D. Mo - - 500* N.D. Na 720 + 40 1.2000 ±1200 Na N&.-24 Nl 1ijt>8.5 k\ 9^ 25 t 1* 270 i 10* Ni _ Pb 36* 2" - i'b - - 30* _ Sb kit 18 4 I* Sb Sb-122 564.1. 1.3 0.9 180 * 40 90 1 20 Zn Zn-65 1115 20 N.D. 90110* 15* 1.5* Zr Zr-95 756.7 400 N.D. N.D. = not. determined The data in the Table 2 are mean values from 3 parallel determinations K- determined by AAS and are characterized with the standard deviations ( Ji tr) . 63 DETERMINATION OF MERCURY CONTENT IN MILK POWDBR H. Iovtchev, T. Grigorov, D. Apostolov Institute of Nuclear Research and Nuclear Energy Boul. Lenin 72, 1184 Sofia, Bulgaria INTRODUCTION The risks for human organism connected with tne increased content of mer- cury compounds in some foods require a systematic examination of the different components of diet. Along with the particularly Important control of the concentration of oeroury in certain products (fishes, mushrooms, some animal internal organs) about whioh general accumulation of the element is established and a compari- son with the existing nowns of content is necessary, for the elucidation of the total mercury exposition, it is neeeesary to analyze products with compa- ratively low Hg concentration but with a high relative share in human nutri- tion (e.g. flour, milk and products from them) /1-4/. In this respect it is interesting to examine humanized milks which during a certain period of human life - in mixed and artificial feeding of new-boras and sucklings - are the basic and almost the only possible food. EXPERIMENTAL lea ized full cream cow milk powder for new-borns (sample A: Bebe 0), sucklings (sample Bt Bebe 1) and small children (sample C: Vitalact 2); bio- logically soured milk powder (sample D: Biolacton). The samples weighing 300-500 mg are activated for 18-24 hours in a neu- tron flux A 5.1 + 2.1 3.6 7.3 B 5.8 + 2.3 3.4 7.6 C 7.2 ± 3.1 4.3 8.7 D 6.8 + 2.3 4.7 8.4 Table Is Concentration of mercury in milk powder /ppb/ Refe- [Hg] rencs (ppb) hi 5 1 12 IM 10 3 29 IMX 0.6 4 157* 5 8 lllx 20 25 la/* 0.1 1 lit 70 180 hoi 2.5 (IASA-A-11) 1 - Values for Hg concentrations in freBh milk Table 2t Comparison of mercury concentrations in milk powder and in fresh milk CONCLUSION The results show concentrations of mercury in the analysed humanized full cream cow milk powder considerably under the recommended by WHO Taluea for food products* At the measurement one must exclude the contribution of Se-75 in the peak area of Hg-203 at 279.1 keV. The method applied gives a possibility to determine mercury by compa- ratively simple radiochemioal prooedure. This la very important in case of large number of analyses for assessment of human organism burden with this toxlo element through food products. REFERENCES /1/. R. Sohelenz, J.-E. Diehl: Z. Anal. Chenu, 26£, (1973) 93 /2/. R. Schelenz, J.-E. Diehl: Z. Lebanon. Unters.-Forscto., 15J. (1973) 369 1S3 (1973) 151 /3/. 0. Birke, et al.: Arch. Envir. Health, 2£ (1972) 77 /4/« K. Heine, A. Wiechen: Milohwissenschaft, 2J, (1972) 688 /5/. J. Huzicka, C.G. Lammt Talanta, 16 (1969) 157 /6/. L.J. Qoldwater: Soi. American, 257 (1971) 15i cit. in /4/ lit, B. Weigand-EschraghiB, et al.t HBB. VerBff. Nr.1 Mercury; cit. in /4/ IB I, J.J.H. de Qceji, et al.: Symp, USA (1972) SE 157/8 191. R. E. Jerves, et al.: ASD-Conf. (1970) 349-002; oit. in /4/ /TO/. R, H. Parr: IAEA/RL/103, September 1983 Simple and fast determination of Rb and Cs in mineralized waters. E.Taskaev Institute ofNuclear Research & Nuclear Energy, boul.Lenin No72, 11B4-Sofia For the technological control of mineralized uaters processing a simple and fast method for Rb and Cs determination uas proposed. The direct determination is rather difficult because of the very high content of Br,Na, Fe and etc* Sodium tetraphenyl borate (Kalignost) uas USBC) for the precipi- tation of Rb and Cs (i). Experimental Tuo 20 ml portions from each uater sample uere used for the determination one for the Rb and the other for the Cs. The pH of the samples had to be about 7. Precipitation of Rb and Cs uas carried out uith 0.11*1 solution of Kalignost* Its quantity depended on NH4, K, Rb and Cs content in the sample. The precipitate uas filtrated, washed uith 0.011*1 Kalignost solution and slightly dried with air, passing through it. Then the precipitate uas packed in polythene capsule. Solutions of RbN03 and CSNO3 uere used as comparative standards. Samples and standards uere irradiated in one of the vertical channels of IRT-2000 reactor in Sofia using pneumotube with 1.5mm Cd filter (2). Epithermal neutron flux uas 10.10'° n.cm—2.s-1. Irradiation time uas 1. min for Rb and 5 min for Cs. 86m-Rb (T1/2=1.O1B min Ev =555.8 kev) and 134m-Cs (Ti/2=2.9 h E =127.4 kev) uere used as analytical isotopes. Cooling and counting times for Rb uere 30 s and 200s. Cooling and counting times for Cs .uere 2-3h and 300s respectively. Y-Spectrometer uith GeLi and multichannel analyser uas used. Interference of B2-Br (Ti/2=35.4h Ej"=554.3 kev) uas checked. It turned out to be negligible in the described conditions. Some preliminary tracer experiments uith 134-Cs and 86-Rb uere carried out to establish the chemical yield of the precipitation. The yields uere rather high and if soma flagrant errors had not been made, it uas 87—13% for Rb and 92-8%for Cs. Since the procedure included only one step precipitation, the rough errors could be obvious and could be eliminated easily. And in the case of technological control, the chemical yield, accepted from the tracer experiments, uas considered to be sufficiently accurate. Carrier free 137-Cs could be usad for more precise control of chemical yield if necessary. Results and discussion The proposed method uas used for the determination of Rb and Cs in highly mineralized underground uaters and sea lye. As the one step precipi- tation uas not enough to remove the sodium comletely, irradiation uith epithermal neutrons reduced the 24-Na activity in the sample and improved the counting conditions. The quantitation limits from 20 ml samples uere 14.10~6 g/l and 8.10"6 g/l for Rb and Cs respectively. The possibility of Ag determination should be mentioned, and the sensitivity is higher when 110-Ag (T1/2=24S Ek*=657 kev) uas used, instead of 108-Ag (T1/2=2.41 min E^=633 kev). Reference 1. "Analytical chemistry of Rb and Cs", Nauka (1975) Floscou, pp59-61 ( in russion ) 2. Apostolov D., Nuclear Energy, 3 (1976) 109-111 ( in bulgarian ) DO GAMMA - 8PECTR0METRIC SYSTEM BASED ON PERSONAL COMPUTER "PRAVETS-83" K.Janaklev, L. Tomdiv, T.Grigorov, M.Vutchkov Institute of Nuclear Research and Nuclear Energy Boul.Lenin 72, 1184 Sofia, Bulgaria INTRODUCTION Gamma spectrometry is an attractive technique for elemental analysis, especially for multjcompo-'nent speciments. The neutron activation analysis is one of the most sensitive analytical methods wridely used by now in sfci- ence as w-ell as in industry. A gamma spectrometric system based on a personal microcomputer "Pravets^ -83 " has been developed in the Institute .-for Nuclear Research and Nuclear Energy. The distinctive peculiarity of the proposed system is that the multi- phanel analyair is realized on the personal microcomputer, which gives thegos- iifeility. the system to work in real time. HARDWARE OP THE SYSTEM The system includes all blocks of Jthe spectroraetric tract - from prea- mplifier to computer for data processing. The preamplifier is in parallel way conected with vlth the detector pow» er supply and has the following characteristics: - noise at zero capacity of the output - 0.7 kev for 3 «fsj - slope of the noise characteristic - 15 ev/pf; / - sensitivity - 90mv/Mev; - maximum charge - 100000 I:.ip./s. The linear part of the spectrometer includes: 1.High-voltage source for power supply of semiconductor detectors. It has the following characteristic: - range of power supply - 0 • £ 5000 v with internal selection of the polarity; "" - maximum output current - 100 uk\ - working temperature interval -from 10 C till 35 C; - the source is efficiently protected against overcharging of the preamplifier at voltage leaping. - a special electron eheme controls the level of the output signal and in this way the source is protected. 2. Spectrometric amplifier with the followihg characteristics* - gain range - from 20 till 1500; - shaping time constant - 1, 2, 3, 6us; - nowise at the input - 6 T; - temperature gain shift - 0,01% / C ; for the temperature diapason fom 0 till 50°CS - integral nonlinearity - 0,1%. The regeneration of the zero line is strobable with the functional thre- shold defined by the noise level. The multichannel analyser is based on the personal computer."Pravets"- 83", Bulgarian production, which is analog to Apple II.Analogue digital converter (ADC^Canberra" model 8075 with 8192 channels and 100 MHz time frequency is used. The ADC data are accumulated directly into the computer memory through Direct memory access (DMA) controller with increment time of the memory 2*s. The volume of the operational memory necessary for spectrum accumulation is 12K, The form of the recorded data ( number of channels and capacity) depends on the number and the type of used ADC. The computer can operate to 4 ADC. Thle system can control the following types of peripperipheral l devices* - metric printer of lipson RX80 on which accumulated spectrum can be pri- nted in letter, figure and profile type ( fig.1); - digital plotter VATANABE type on which the spectrum and itB processing by the applied programmes is drawn graphically; - two floppydisc devices with bilateral record and double density; - Full compatibility is ensured with the computer Apple II and hardware and software extensions. SOFTWARE OF THE SYSTEM The computer based multichannel analyzer is equipped with system software including the following modules: - spectrum vizualization in linear and logarithmic scale which can be 67 Pig.1 - Tipical gamma spec- trum accumulate by proposed system without background subtraction. Fig.1 3072 Pig.2 - The same gamma spec- ; 2,. 4 trum with background subtra- ction by method of Gunning. SEC 0000 Pig. 2 change* along X and Y coordinates, simultaneous vizualization of two spectra, region of interest; - programme GAMMA-X which 1B desined for complete analysis of a Ge - Li type gamma spectrum. Gamma - X takes 4096 channels spectra. It has been opti- mized for o,5 Kev / channel and a detector resolution of 2.7 Kev at energy 1332 Kev. Gamma-X detects peaks, peak boundaries, peak widths and multiplet structures with a convolution technique based on a square wave convolute. Two important calibrations are required in order for Gamma-X to be able to analyse spectra from different gamma spectrometers systems: parameters for conventiona]lchannel units to energy and parameters describing the system reso- lutions as a function of energy. These calibrations have to be carried out for energy detector system. In order to compensate for small gain shifts, two monitor peaks are used ( 59.5 Kev peak of Am - 241 and 1332 Kev of Co - 60 ). The statistical significance of the transform results is tested to eliminate spdrioue peaks by using a two - standard deviation criterion. The next step is to locate the peaks by scanning down in the contrast spectrum for nonzero values.The edges of the peak are searched in the square wave convolut spectrum in the negative region. The background is computed as a staight - line functi- on between the peak edges hy using a 3-channel average for the peak - edge count. The continium subtraction technique is based on the method of Gunning- Philippot. For resolving overlapping peak structure a partial - stripping decomposition method is usred, restricting overlap region to 3 channels. Pig.2 and 3 show a tipical gamma specrum obtained from the primary coolant circuit of APS "Kozloduy" before and after its treatment. The sequence of spetrum treatwwat with built in siBtematical programs can be given at routin work of the analyzer. 68 The programme languages for the user's software are BASIC, FORTRAN, PASCAL, PILOT. 50 The spectrometer is tested with standard source Co and shows the following exploatation characteristics: - resolution PWHM for an energy 1332 kev - 2.7 kev; - shifting of the peak at charging with 50000 counts per second - © 0.03%; - shaping time --3- Microseconds. CONCLUSION Gamma - spectre-metric system was developed and the prototype was tested. The results are comparable with these received by comercialy available equipment. The main advantage of t'he suggested system is that it is not necessaxxy to transfere the data fr.om the multichannal anlyzer to the memory of the computer. OQMPUTATIOHAL DBSORIPTIOH 0? VAST VSUTRGB ACTIVATION DATA Marileaa Avrlgeanu, H* Ivaaou Inatitute for Physios and Nuclear lagineerlng Buohareat-Magurele, P.O.Box 1IG-6, 76900 Romania 7. Avrigeanu Inatitute for ffuolear Power ficaotors Piteeti, Romania INTRQDUOTIQH following the developaent of aorc Intense aouroes of 14 MsV neutrons la the past faw ysara, there baa been growing laterest la the lnatrumental aulti- • eltaeat faat-neutron aotivatioa analysis (ISAA). It ia haped that ths FIAA oau complement the thermal-neutron aotivatioa analyaia (TNAA) for certain typea of analytioal problaia /!/• faat-neutron reaotloaa prooaad along thraa relatively atroag reaction ohanaalai (a,p), (a««C) and (n 2n). However, the ezperiaental oroaa-seetion data baaia of praotical uae ia( aotivatioa analysis la rather scarce (e.g./2/). An aoourate theoretioal daaorlptloa of thsae reactions ia aa uaeful alternate way to aupport FHAA* Tha sala taak la perforaing auoh theoretioal oaloulatioas of fast-neutron oroaa aaotioas froa threahold up to 20 1ST, baaad on the* atatiatioal model (Bauaer-feshbaoh STAPB1 ooda) and the preequllibrium deoay geometry dspeadaat hybrid Model, are presented la tbJ.a contribution. The appropriate onoioe of conaiateat aata of input parameters, free of adjuatabla parameters aa muoh aa possible aad uaed la an unitary way, achieved through analysis of Independent data, has great ly determined the aoouraoy of this approach /3/. The (n,p) aad (n,2n) reactions on 92-Ho have been ohoaen to illustrate our goal, as molybde- aua ia aa important fualoa technology aatorial aa wall aa biological tiaauaa ooapoaaat whoae oonteat determination through TNAA haa already been carried oat/4/. NUOUtAE MODIL PAHAIBT1RS Optical model parameters (OHP) aet for neutrons ware ohoaen by tha SPRT method /5/. By aaalyalng the oaloulatad a - aad - p wave atreagth functions, poteatlal aoattering radiua, total oroaa aeotions between 1.5 and 5«J» MeV, shape elaatio aoattering oroaa aeotions up to 4 lev againat the available ex- perimental data, tha Lane ooaalataat OHP daduoed by Lagrange /6/ proved to be the moat appropriate for lio* Tha proton OMP of Johnaon at al. /7/ with tha energy dapaadaaoe auggea- ted by Tiigrange /8/ have baaa adopted following the analyaia of the reaction oroaa-aeotiona for both the ayatem p + 93-Hb aad tha 9?-iBb(p,n)93-*o reaotioa up to 5*5 HaV. Alpha-partiole aad dautaron OUP obtained from data ftta in this aaaa aad energy range /9|1O/ have alao been uaed. QaamaHray transmiaalon ooaffloiaata wara baaed on tha abaolute 1 1 gamma ray atrength functions generated by Beans of the energy-dependent Breit-flgaar (*Bt) aodel /ll/. B J ™ Tha nuolear level density ahould ba differently traatad aooordiag to tha following thraa ezoitatioa taergy regiona. iTLow axoitation energies (l*s© 2 ta 4 HaV) delimited by tha maxlmua axoitatlon energy wart almoat all the dlaorete levela KM believed to ba wall known froa experimeats. « II. Maditta excitation energies (?^I ^ 10 HoV) la the definition domain of the aemiempirioal Back-Shifted lermi Gas (BSfG) model. Ita parametera (the leve-l densit- -• y paramete- r a aaand the baok-ahlftabad — d- A* of.. th. a grouad-atatejuad-atat k) are ea- tabllahed by the ouaulatlve auaber-of low energ__y dlaorete levelivela anaad the ave- rage nuolaoa reaonanoresonance apaoiaga V*?v* *•. Tha fittad values of theae paraaetera to the aoat raoaat experimental data are aometinea readjusted mainly when the ex- perimental data baaia waa rather soaroe. III. High, excitation aaarglea (E*£? 10 MeV), where the B8VG parametrlsa- tlon fails gradually aa tha atrong shell affaota observed ia the level density paraaeter A »t lowar enarglaa dlaaappaar with the iaoreaaa la exoltation. la this oonneotion, Ignatyuk at al* /12/ have introduced an energy dependent le- vel daaaity parameter a (1*), atartlng from the experimental evidence of a oloae oorreapoadenoe between the a. valuta derived from the neutron reaonanoe data and the experimental shell correction Supported by the 1.P.H.I, and IAIA - Vienna- Oontraot 2983 / BB 71 ABSOLUTE NONDESTRUCTIVE QUANTITATIVE DETERMINATION OF URANIUM IN SPECIAL NUCLEAR MATERIALS U.Dragnev.B.DamSanov, G.Grozev, J.Karamanova Institute of Nuclear Research and Nuclear Energy Boul. Lenin 72, 1184 Pofia, Bulgaria INTRODUCTION qualiigfc of the non-destructive gamma- and X-ray measurements depends strongly on the calibration and the standards. At present the most severe rest- riction for the widespread application of non-destructive quantitative measu- rements of special nuclear materials (SNM) is the lack of suitable standards or methods for accurate absolute measurements.The preparation and accepted Bar- tification of standards appropriate for non-destructive quantitative measure- ments and their use by IAEA nuclear material .afeguards is extremely difficult and time consuming because of the large variety of sizes, shapes, concentra- tions, cladding, etc. of SNM items available in different countries. In addi- tion,^the transportation of standards from site to site in one or various countries is quite difficult because b£ the existing regulations. Therefore, the development of absolute non-destructive methods and corresponding proce- dures and instruments, which means methods with a reduced number of required standards, suitable for IAEA nuclear material safeguards applications, is of a great importance. The object of this work is to develop absolute non-destructive method for quantitative measurement of Uranium concentration and enrichment in SNM.An Intrinsic Calibration method has been proposed to Bolve this problem, the ob- tained results show good agreement with.clasical known methods and in some cases better. 1. GENERALIZATION OF THE INTRINSIC CALIBRATION CONCEPT* Intrinsic calibration of high resolution gamma- and X-ray spectrometric measurements is a quantitative use of correlations between peak position,sha- pes, areas and their ratios in a measured spectrum and corresponding known or measured values of gamma and X-rays energies, emmiting rates, material matrix and other parameters in order to calibrate the measurement system and/or meat* surement results, in general without use of additional standards. At the begining, the intrinsic calibration was developed only for obtai- ning of overall relative efficiency dependance and isotopic ratios from high resolution gamma spectrometric measurement/1/.During the last years this app- roach has found wider application. The intrinsic calibration technique uses the results from the measurements of the sample itself, reduces the number of required standards, the measurement time and errors and increases the reliability of the results. General procedures of the intrinsic calibration are following: energy ca- librat&ft.ff the measured spectrum,callibration of the peak width, efficiency calibration. Using strong and well known lines and having the areas of the peaks from one isotope or from several isotopes with known isotopic ratios and their branching yelds (B) the overall relative efficiency (E) can be determined with adequate accuracy.This allows an absolute determination of the isotopic ratios and in some cases when well known standards (samples) are measured the nuclear data can be determined more precisely. 2.DETERMINATION OF THE PEAK PARAMETERS. The measurement equipment used in this work consist ofointrinsinc Ge det- ector with resolution 1,7 kev on the energy 1330 kev of Co , multichanal ana- lyser "Silena" and powerful programabte calculator HP-41CV. Determination of the peak parameters is made using a Gaussian fit.It is known, however, that the pe-ik shape is not precisely a Gaussian one, in parti- cular because of the "tailing11. The problem is to determine the fraction of the single peak to be used in the determination of the gaussian parameters. In /2/ only the part of the peak in which the first and last channels are at a dista- nce 0,8 (FWHM) from the peak maximum position is used. Other authors use the condition Q,5 (FWHM). We found that the dispersion o-*of the Gaussian distribu- tion of the number of counts in the peak channels depends on the number of cha nnels used. Experimentally it was established that the minimum value of (T is obtained when the first and the lapt channels ueH are at a riirtance 0,o(FW**!) from the peak maximum position. In many cases the peaks used are not single ones. They consist of several peaks groupped together. There are procedures and programmes for resolving a complex peak but they are not suitable for calculators and it was neoeesary to develop a new one. 72 The following procedure is proposed: first th fn__ ^* ? sigmas <5j and the positions p.. of maxima of the peaks which de and u^T^ i63^ determined. The energy and sigma calibration are ma- ae and used in- o-rder to determine the P and «, for the individual peaks. In determing the individual peak argis *»«•*•• £l K = oi OiV^ i - 1.2 n m the following formula is used: v where m is the number of the peakB forming the compound peak and N is the numberoof net counts in a channel p. Using the least square method and pstati- stical weights of the number of net counts it is pdssible to determine the in- dividual peak maximum counts N ,. It was established that to determine the compound peak areas with a (rood accuracy the individual peaks forming the expound peak have to be at a distance 1 sigma from each other. In order to determine the individual peak areas of an unrecolved compound peak using intrinsinc calibration the following system of linear equations must be solved: Ni ——; k= 1,2, ....n >5\ x y N 'JO i-1 j=1 i ^i0 j0 tjO i0 where n is the number of the isotopes emitting gamma quanta within considered energy region; Ok is the number of the single lines participating in this energy region T± is the half live period of the isotope i; (B^)., are the branching intensities of gamma rays with energy j from the isotope i; 0 is a subscript of the parameters of the peak which overall relative efficiency is accepted to be 1; £ .. m£L is the overall relative efficiency at energy i; N, is*the number of nuclei of the isotope i. The net area of the peak region Sk may be a compound peak area. Using thiF approach the isotopic ratios can be determined without resolving the compound peak. It is convenient and the renults are accurate. This procedure was propo- sed and used first in /1/ where it was described in more details. 3. PROCEDURE FOR URANIUM MEASUREMENTS. In order to determine U isotopic ratioB, U-235 enrichment and U concentra- cion use of the narow energy range (84-93) kev iB proposed. The following peaks are used: 84.24 kev gamma rays emitted by Th.231, which is practically always in equilibrium with U-235; 89.942 kev Th K^? X-rays and gamma rays with the energy emited by Th-231; 9 2.367 kev gamma rays emitted by Th-234, which should be in equilibrium *lth U-238; 92.792 kev gamma rays emitted from Th-234; 93.35 kev Th K^, X-rays; 94.666 kev U KL,1 X-rays; 98.441 kev U K^-f X-rays. The lines 92.367, 92.792 and 93.35 kev form a compound unresolved peak called "92.8" kev peak. The areas of the above peaks are determined using a linear background subtraction. The overall relative efficiency dependence in this energy range is dete- rmined using the 84.24, 89.942, 94.666 and 98.441 kev peaks. It is assumed that the overall relative efficiencies for these four energies are lying o-n a Becond degree curve a + a E a E e * * 0 1 i + o ^ C98.441 i where £, is the overall efficiency for the energy 73 The energy dependance of the overall relative efficiency is determined by this equation. Calculating 34.24 and 89,942 by this dependence the branching B ,.. J 98.441 98.441 is determined to be: B89.942 0.3812 +/- 0.0065 B 84.82 Jt ls Pr P d h intens +*. * -i ? S«o QJ f i*y ratio of the 94.666 kev U X, X-ray line to the Unresolved "92.3" kev peak to be used as a measure of concenttitration^ 3 S94.S66 £94.666 92.8 This has the following advantages: i. The lines are very close to each other so the correction for relative change of the overall detecting efficiency is not large; ii. The compound peak with an average energy of "92.8" kev ( including 92.367kev 92.792 kev and 93.35 kev lines ) represents all possible sources of inner exi- ting radiations. The results of the measurements on powder and pellet samples of different size, shapes, concentration and enrichment are given in following table: COMPARISON OF CHEMICAL AND SAMPLE "CHEM/"A5ALT XRF-GSM~ X-RAY FLUORESCENT - GAMMA C AC C AC SPECTROMETRIC MEASUREMENTS A 87.97 0.05 87 .97 0.13 B 37.84 0.08 33 .01 0.13 (XRF - GSH ) OF CONCENTRATION 0.06 87 0.08 8 B:» 0.08 87 • 51 0.16 OF SOME SAMPLES E 37.80 0.09 37 .69 0.03 F 87.74 0.03 87 .80 0.11 G.34..656 . Q_.Q2 34468 Q.15 IT was established that: 1 ) This ratio does not depend on the size and the shape of the measured samples which makes the calibration very convenient; 2) The precision of the measurements (0.2 - 0.3)% at 2 (J level depends mainly on the measurement time; 3) The intensi- ty ratios depend on' the enrichment of the measured samples. 1?6 change of the enrichment gives 0.3% change of the intensity ratio. To measure the concentrati- on correctly through thiB intensity ratio one has to know or measure the enrichment of the measured sample. _ ?,s The following formula is used for the determination of the »-«•§ ratio: S 1 £89.942 92.8 £93.35 (7) 89.942 85 £92.6 w/here t, is the overall relative efficiency at energy E,; S. is the peak areas of the energy E.; [8 '92.6 k K 85"Tg 39.942 93.35 S89.942 Y + 8 e .6 ( ft)o>3 *C7 (TCo)oo too * *^ branching intensity from B ne and (Ye)Qg Q42 ^ * branching intensity of Th Kjg 89.942kev line of U, Te and Tg are the half life periodB of U-235 and U-230 isotopes. In de beaming the U-235 enrichment is. usedlthe formula Enrichment = 1 + The coef.Koe and iC^ were determined by least square method. CONCLUSION Method for U isotopic ratio and concentrationWs^ng intrinsic calibration and portable instrumentation is developed and tested^It is particularly suitable for IAEA safeguards applications.The intrinsic calibration accumulates the posi- tive experience of the previous measurements and the results will be improving constantly.lt is possible to measure standards mainly in the laboratories and to use the results for analysis far away at different time and places. REFERENCES I.Dragnev T,N., IAEA/STR-60,(1976) and J.Radioanal. Chem., 36 (1977), 401. 2.Von Meerwall E.D., Gfalvik M.JD., Comp. Phys.Communic. ,v.7,No 3» (1974), 115. 74 PROGRAM FOR THE QUALITATIVE AHD QUALITATIVE ANALYSIS OV ft*-RAY SPECTRA V.Obpelea ,E.Purice,R.Dan,Q.Calo«T,M.Domni8«n,V.Qalia,G.Teodosiu Researon Institute for Computer Technique,Calea Floreasca,l67, 72321 Bucharest,Romania C.Debert Institute for Nuclear Power Reactors,Bucharest,Romania N. looanu ,M. Nastase Fundeni Clinioal Hospital,Calea Fundeni,258,Bucharest,Romania INTRODUCTION The described computing program assures the quantitative and qualitative analysis of the speotra obtained within the neutron activation analysis method. It is meant for the laboratories interested in detecting and determining the concentration of certain elements (i.e. medicine,biology,metalurgy labs). RESULTS AND DISCUSSIONS The program processes regular spectrum obtained from the irradiation with neutrons within test standard terms of a sample and measured by a Ge(li) detec- tor. We can use both a TN 17o5 multichannel analyser and a romanian MCA 79 one, both with Io24 channels,the interfaoe with the computer being performed by ITC. The program has been made and Implemented on the roumanian microcomputers FELIX M118 and FELIX M216 and has a modular, struoture whioh facilitates its use and debugging.The spectrum processing by the program is performed off*-line, after having been memorized on a floppy disk. After introduction, the speotrum is dumped on display, enabling selection and extension of some speotrum windows with cross-hair facilities.The next step is to determine the background paramaters(the background is supposed to be a polynomial of degree 1,2 or 3)* Further on comes the gaussian ourves fitting using the least squares method applid to the equations 3 7 Y(x)-ax +bx +ox+d+ 2E y. exp(- (x-xoi f /a«£> (1) The fitting process oan be aimuoltaneously made on maximum lo gauasians and starts by introduction (by the user) of an initial evaluation of parameters (it may be performed either by a oross-hair or may be taken from another spec- trum analysis program of smaller resolution,for example the PRAO program). The gaussian curves fitting is lucratively made,ending either whan exceeding an Iteration maximum number or when the process converges.lt is accompanied by the permanent dump of the initial speotrum as well as of the one calculated af- ter each iteration,In ease the prooeas does not converge it is recovered with a relntroduotion of the gaussian Initial parameters.The identification of the ele- ments la performed using a polynomial relation betwaan energy and channel,ob- tained by the calibration of the device with a standard sample. Further comes the caloulus of the peak-areas (by Integration) and the ele- ment identifying module,by searohing In the library associated to the program. The oalculus of the elements concentration (elements previously identified in the sample) is made supposing that the relation between then and the Induced activities is known. Finally the program puts at tha user's disposal the list of the elements Identified during the test,together with their concentrations,in the form of an analysis report. REFERENCES /I/ W.L.Zijp.Leoture notes on computerized gamma-ray spectrometry,ECN,febr.l9B4 /2/ V.Tepelte,E.Purioe,G.Teodoslu,V.Galls,B.Mooanu.PRAG-program for antropoga- mmametrlo analysis 75/ %6> C START Initialization of //>e program I •Spectrum selection fromthe spectra Library I c/ u WIND, Selection and extension f in the spectrum 1 BAK Point selection far bctckqround calculus * I Calculus of the" backs port/met L Introduction of the initia/ gaussicrn parameters r FIT I Baussiati curves weeding* ion maximum number CALIB Energy/ channel calibrat/on I I DENT Element identification in Hit library AREA Area calculus CONC ConcentrationI calculus OUT Resulfa di 711 MEDICINE AND BIOLOGY 79 INVESTIGATION OF THE BEHAVIOUR OF SOME ELEMENTS IN HEART OF THYMECTOMISED RATS L.Kinova Institute of Nuclear Research and Nuclear Energy,Sofia,Bulgaria INTRODUCTION Tne thymus gland is known to be the primary regulator of the immune defence in the organism.Later it was recognised as an endocrine organ,therefore it participates in the regulation of the metabolic processes as well.For the maintenance of normal flow of metabolism some essential elements are required. From this point of view the investigation of elemental behaviour after the removal of tne thymus gland (thymectomy) will give us an additional informa- tion on the significance and functions of the thymus gland in the organism. EXPERIMENTAL Determined were elements K, Mn, Ca and Zn in heart of normal (intact) and thymeotomised Wietar rat8.Thymectomy was performed at the age of 3 month. Analysed were hearts of intact animals at the age of 3, 6, 9 and 12 month and hearts of thymeotomised animals at 15 days, 3t 6 and 9 month after thyicec- tomy.Determination of the elements of interest was carried out by means of instrumental neutron activation analysis.Collection,cleaning and storage of the samples.as well as the irradiation,cooling and measuring mode and ana- lytical isotopes used were described in other our work (i).The results obtained are presented in ppm in table 1. Table 1 INTACT THYMECTOMISED r INTACT THYMECTOMISED K 9275 +713 8664 + 1001 11467 + 864 12833 + 1010 Mn 2,79 + 0.22 < 1 3.91 + 0.22 <1.4 Zn 76 + 4 59.3 ± 2.2 72 + 3 84 + 4 Ca 164 + 13 976 + 98 I 118 + 8 134 + 10 K 12100 + 445 13830 ± 857 10670 + 956 10990 + 820 Mn 4.59 + 0.36 2.27 ± 0.19 2.78 +0.11 1.98 + 0.17 j( Zn 74 + * 96 + 7 1 79 + 4 42 + 3 DISCUSSION From our investigations it was established that the changes in the concentrations of the elements analysed are most demonstrative in the earli- est term after the tnymectomy (15 days ).Por example observed are decrease of K, Mn and Zn in comparison with intact rats.For the same term after thymeotomy Ca concentration in heart increases. According to the literature the decrease of K and increase of Ca in myo- oard (resp. increase of K and decrease of Ca in serum) leads to slowing of the rhytm of heart beating because of difficulties in the transition of the nerve impuls to heart muscle (2) .The changes in K and Ca concentrations observed by us in myocard of thymectomised animals are in agreement with the investigations of Kosarev (3), who established decrease of the frequenoy of heart beating in ratB after thymeotomy. According to some authors (4)» changes in the electrocardiogram in this case are characterised by elongated S-S interval and diminished T-peak. On the other hand it is known that Mn defficienoy leads to a reduced oxygen uptake (5) for the reason that Mn is a well known activator for many oxidising processes in the organism.We found a significant decrease of Mn in the myocard In the earliest term after thymectomy.Together with the alteration in the metabolism after thymectomy this faot might be an explanation of the results of Usunova(6) - elongation of S-T interval as it dependes strongly on the alteration of metabolical processes and especially on the oxygen uptake. The ECG changes mentioned remain in the later terms after thymectomy synchro- nously with the lower oontent of Mn in the myocard of thymectomieed rats (7)* Our results show a sharp increase of Ca in myocard in first investigated term after thymeotomy - 15 days.Increase of Ca is a oause for the rise of his- 80 tamine level in myocard muscle since Ca is a liberator of histamine from the mast cells .Although this rise of Ca is observed for quite a long period up to 6 month after thymectomy - the histamine level in the heart of thyme- ctomia«d is higher than in feeart of intact rats only in first term analysed ( 15 days ) after which it falls down under the level of normal (intact) animals ( 7 ).Probable explanation for this fact could be the subsequent rise of Zn ( 3 and 6 month after thymectomy), which has been shown to inhibit histamine release from the mast cells and thus acts as an antagonist of Ca(8). In the latest term ( 9 month after thymectomy) investigated the Zn level in thymectomised heart falls down under that of intact animals which leads again to a rise of histamine level.The behaviour of ratio Zn/Ca in heart of intact and thymeotomised animalB is shown on fig.1. Fig. 1 Following the alterations of the elements analysed in the latest terms after thymectomy a tendency toward a fall under 0,6 the normal ( of intact animals) values is observed. O 1VTHCT \L X THYMBCT. 1Z —•• CONCLUSION The data summarised in this work show that the removal of the thymus gland impair the metabolic processes in the organism.The attempt made by us to explain some of the alterations in the heart after thymectomy by the changes in the concentrations of elements analysed gives an opportunity for a further clarification of the role of the thymus gland in the organism. REFERENCES /l/.L.Kinova ,M.Iovchev,T.Grigorov,D.Apo8tolov,Z.Kemileva|Proc.3.Tagung Nuoleare Analysenverfahren,11.-15*4.1983,Dresden,DDR /2/#A.Ado,L.M.Ishimova» Pathological Physiology, Medicina,Moskva,1973 /3/.I.Kosarev \ Dias.,Varna,1972 /4/.K.Velikov i Diss.,Varna,1971 /5/.E.Underwood i "Trace elements in Human and Animal Nutrition", Academio Press,London,1977 /6/.A.Usunova j Diss.,Varna,1968 /7/.Z.Kemileva \ Thymus , Medioina i fiscultura, Sofia,1979 /8/.Q.J.Brewer i Trace Elements in the Pathogenesis and Treatment of Inflammation , Birkhauser Verlag,Basel, 1981 81 THE FEASIBILITY STUDY OP iN-VlVO ANALYSIS OP BONE CALCtUM BY ACTIVATION OP HAND WlTH 5 Ci 238Pu-Be H .Sevimli Qekmeoe Nuclear Research Center F.K.I Havaalam-ISTANBUL-TURKEY INTRODUCTION Throe main olinoal methods are used to evaluate the mineral content of human bone: Radiography,semi-quantitative histology performed on a biopsy from the iliac crest and absorptiometry praoticed on the forearm. The poor sensitivity of radiography and the distress oaused by the biopey process necessarily limit the use of these techniques. The absorption curve produoed by the bone mineral analysis concerns a "total bone mineral" per unit length of the bone scanned but not the calcium content of this bone. On the other hand neutron activation analysis, which is non-destructive, is an ideal method for the qualitative and quantitative determination of bone mineral elements in living subjects. An in-vivo neutron activation technique (IVNAA) for the measurement of calcium was proposed by Maletskos in 1961 (1), performed on man in 1962 by Anderson et al (2). In several large centers, this technique was used to measure the calcium mass or calcium concentration by using whole-body irradiation for studies of osteoporosis. (3-6) For a number of reasons-differing tissue sensitivities to radiation, difficulty and cost of obtaining a uniform whole-body irradiation,«tc-It was started to investigate the calcium metabolism by partial-body neutron activation technique; in hand (7-10),tibia,spine (11-12) and foream (12). Required neutron flux is provided mostly by isotopic neutron sources,cyclotron (11-13) and D.T generators. Ideally one should measure the mineral content of lumbar vertebrae,where metabolic damage is detectable earlier. But neutron irradiation of the vertebra present difficulties,both in administration technique and in the results (since the aorta is often calcified). Furthermore,in other bone diseases (hyperparathyroidiBm and renal osteodystrophy) mineral lose is early and marked in the hand (14) where the soft-tiBsue component is small, and the peroentage of bone in the hand (v/v) is about twice that for the whole body .Therefore it was decided to use the hand the neutron activation analysis. EXPERIMENTAL The .ga (n,")() Ca reaction was employed for the analysis of calcium.(f»0,185 $ 6VL.lb 1-900 mb) 49ca,has 8.8 min. half-live and emits 3.1 MeV gamma photons .The gamma intensity is proportional to the mass of stable caloium exposed to the thermal neutron flux. By comparing the induoed *9Ca activity with that of a standard of known chemical composition, it is easy to measure the mass of stable caloium contained in the bone segment examined .Or to determine the ohanges of calcium amount .Measurement may be repeated three of four times a year. 5 Ci 23sPu-Be isotopio neutron Bouroe was used for irradiation.Total emission of source l.lxlO? n.Bec"1 . The whole irradiation device is shown on Fig.l. Hand phantom tubeB were placed into the tubes of device which is put in the middle of tank,around the souroe. In order to obtain sufficient precision it was necessary to perform four 10-min irradiations each followed by a 1000 Bee. counting period .After each irradiation the tubes were trensfered to the detector in one minute,a 5"x5" Nal (Tl) well-type detector and a 1024 channel multichannel analyzer were used for counting gamma rays. ,_ It was found out,that the contribution of 3100 KeV gamma rays from "ci (n,p) S ti/2-5.06 min. f-24,23 % is negligible. RESULT and CONCLUSION The mesurements of calcium series were started first by using 14g of calcium which corresponds to the calcium content of i.and .The amount of calcium WBB decreased step by step Pig 2. Standart deviation over a series of ten analysis performed on the same phantom is within 3*. Dose measurements were carried out* by UBing LlF TL Dosimeters on phantom tubes filled with homogenized human bone .The Dose rate was 2,7 rad/h and the hand dose is 9 rem.The best estimate of the 238Pu-Be neutronB RBE appears to be 5 (15).This dose will be decreased by about a factor of two when two 5"x5" Nal (Tl) detectors are used. This dose,strictly localized compares favorably with those commonly delivered during conventional radiotracer examinations such as thyroid uptake tests. According to International Commission on Radiation Protection (ICRP) standards the maximum dose equivalent acceptable in the hand,for individuals directly engaged in work with radiation, is 50 rem per year or 15 rem per quarter.This measurement may therefore be repeated quite safely three-four times a year.The repeatation is essential for the study and treatment of osteoporosis. When the patient irradiation start,neutron souroe will keep in same position, the patient will hold It.in hand.The source will be covered one cm thickness of paraffin wax. x The author thanks Zuhal Ugur for dose measurement. 82 800 tirr 4x10 min «e txttOOs Imin 610 «t 8 Dost 9 ftm Q. •00 1 r -.0,9965 Phantom y = 54,057 >+88,622 Tubas(Scm) 6 10 U Calcium Amount - g Paraffin Wax Fig. 2 - 308A KeV Peak Ar«a against Ca amount in thi hand phantom. Fig. 1 - Irradiation facility REFERENCES /I/ Malketskos, C.J., Keane AT.Littlefield S, etal. Annual Progress Report Cambridge 952 (1961) 68. /2/ Anderson, $., Osborn SB, ToralinBon RWS Lancet 2 (1964) 1201. /3/ Chamberlain, ttJ., Premlin, J.H., Peters, U.K., Phillip, H., Br. Med.2 (1968) 581. IM Cohn, S.H., Fairchild.R.G., Shukla, K.K., In Vivo Neutron Activation Analysis (Proc. Panel Vienna 1972) IAEA Vienna (1973) 37. /5/ Me. Neill, K.G., Thomas, BJ., Sturtridge, W.C.f Harrison J.E., J Nucl. Med. 14 (1973) 502. /6/ TJ. Spinks, D.K. Bewley, A.S.O. Ranicar G.F Joplin Modern Trends 76 (1976) 221. Ill Catto, G.R.D., Uclnsosh, J.A.R., Uacleod M., Phys. tied. Biol., 18 (1973) 508. /8/ Uazxre, B., Comar, D., Kuntz, D., Jour. Radioanal.Chem. 37 (1977) 357* /9/ Guey, A., Leitinne p., Zeoh, P.Y., Traeger Doyen, J.B. Nucl. Activation Techniques in the Life Sciences Vienna 1978 I.A.E.A. Vienna (1979) 701. /1O/ Maziere, B., Kuntz, D., Comar, D., and Ryckewaert, k.t. Nucl.Med. 20K1979) 85. /ll/ Alhiti, K., Thomas, B«t., Altikrity, S.A., Ettinger. K.V., Fremlin, J.H., Dabek, Jt.T., Int. J.Appl. Radiat. Isot. 27 (1976) 97. /12/ Smith, M.A., Tothill P., Phys. Med. Bid. 24 (1979) 319. /13/ Ozbas, E., Chettle, D.R., Ettinger, K.V. Int. J. Appl. Radiat. Isot. 27 (1976) 227. /14/ Catto, G.R., Macdonald A.F., Mcintosh t .A.R., Lancet 1 (1973) 1150, /15/ Hall E.J. In some Physical Dosimetry and Biomedical Aspects of Cf 252 IAEA Vienna (1976) 151. DISTRIBUTION OF SOME ELEMENTS IN HUMAN COLON MUCOSA R. J. Draskovic flw FREQUENCY OF FREQUENCY OF Boris Krdric Institute of Nuclear Sciences, VinEa Cmln max C IN POB 522, 11000 Beograd, Yugoslavia jj o tnin max nKg/g gg DIAGNOSTIC nKg / g M. Bozanic GROUP S DIAGNOSTIC o GROUPS C/H Center " Dr Dragisa Misovic " DIAGNOSTI C GROUPS 11000 Beograd, Yugoslavia 56.91 CCh INTRODUCTION Co 4.23 Aca Zn 28.80 225.10 AT Continuing our investigations of the role of TRACE ELEMENTS in living AT ACa:4(5) CCh : 3 ( 5 ) organisms ( TE - distribution in plankton, alga, shells, bentos, Crustacea, CCh fish, mices, rats, human organs and tissues; liver.brain, kidney,dents ) we Fe 328 ACaAT:l(5) 5652 AT : 2 ( 5 ) have determined some elements in healthy and pathologically altered human colon mucosa, i.e.: ( 1 - 5 ) Cr 1.70 ACa 45.10 AT - healthy - N Sb 4.1 ACa 480.6 CCh - Colitis Chronica -CCh - Colitis Ulcerosa -CU - Adenoma Tubulare - AT - Adenocarcinoma - ACa TABLE 1. MINIMUM AND MAXIMUM CONTENTS OF ELEMENTS IN INVESTIGATED ( The diagnoses were previously verified clinically and histopathologically ) MUCOSA SAMPLES AND FREQUENCY OF THESE PARAMETERS IN DIA - Our aim was: GNOSTIC GROUPS to follow changes of the contents of elements in human colon mucosa as a function of pathological alterations during development of diseases (dia- gnostic series : from healthy to cancerogenic states ). EXPERIMENTAL CHROMIUM C CU > CN > CCCh > CAT ; » CACa The samples were taken for analysis from 80 patients, 'n five diagnostic 23.32 21.06 19.35 14.31 13.23 groups (8-43 patients ). The samples ( 0.00023 - O.OOO87 Kg in weight ) were taken during recto- IRON 9 sigmoidoscopy by teflon coated forceps and washed by bidistilled water and CCCh > ANTIMONY C > c 9 r RESULTS AND DISCUSSION cu ^ CCn AT ACa 265 247 139 86.7 55.69 The results for CE - parameters in healthy and pathologically altered human colon mucosa are presented in Tables 1, and 2. TABLE 2. RELATIONS OF TOTAL MEAN CONTENTS OF ELEMENTS ( C£ - parameters ) in N -, CCh -, CU -, AT - AND ACa DIAGNOSTIC GROUPS CONCLUSION The following conclusions can be drawn: - the obtained C£ - PARAMETERS DECREASE TOWARDS Ca - groups; - minimum values of CE ~ parameters were found for elements Fe, Co, Cr and Sb in the ACa groups and maximum for Fe,Co and Sb in CCh - groups; - in order to prove these conclusions it would be necessary to follow the dinamics of the changes in mucosa, because of its cells life cyclus ( REFERENCES / I / DraSkovic R.J., INVESTIGATION OF GEOCHEMICAL CHARACTERISTICS OF COMPONENTS OF SOME NATURAL WATER SYSTEMS BY NON-DESTRUCTIVE RADIO- ACTIVATION ANALYSIS, University of Beograd, Thesis ( 1978 ) / 2 / Kostic K., Ristanovic R.,Obradovic V., Djordjevic M., Draskovic R.J., Trace Element Analytical Chemistry in Medicine and Biology, W.de Gruyter and Co. Berlin - New York.ed.: P. Bratter and P. Schramel, ( 1980 ), p.p. 601 - 610 / 3 / Draskovic R.J., Jacimovic Lj., ( + ) Stojicevlc M., Pajic' P., Filipovic V. , J. Radioanal.Chem. 70 ( 1982 3,117 / k I Bozanic M., DETERMINATION OF TRACE ELEMENTS IN HUMAN COLON MUCOSA BY THE METHOD OF NEUTRON ACTIVATION ANALYSIS, University of Beograd, Thesis ( 1983 ) / 5 / Draskovic, R., Bozanic K., Bozanic V., Bonus T., J. Radioanal. Nucl. Chem. 8V2 ( 1985 85 ANALYSIS OF HUMAN RENAL CALCULI BY INAA L.Kinova,Iv.Penev Institute of Nuclear Research and Nuclear Energy,Sofia,Bulgaria M.de Bruin Interuniveraity Reactor Institute,Delft,The Netherlands INTRODUCTION Formation of the renal calculi is a long process helped by such factors as an impairment of mineral metabolism,slowed urine flow,defects in metabolism of genetio origin.Functional disturbances lead to some alterations in the elemental composition of the serum and urine,Prom this point of yiew it presents some in- terest to analyse kidney concretions for eventual relation between elemental composition and the degree of illness. EXPERIMENTAL Sampels of human renal calculi were collected from the population of Delft area,The Netherlands.25 oamples were analysed: 14 from male patients and 11 from female patients.Clinical data available consisted of serum creatinine and urea. Analysis was carried out by means of instrumental neutron activation ana- lysis using the facilities of the Interuniveraity Reactor Institute in Delft, consisting of T» ? 2 MW swimming pool reactor with neutron flux 1x10'''n/cm sec Well-type detector Phillips with gold linning 0.4 mm and energy resoluti- on 1.8 and 2*3 KeV at 122 and 1332Kev respectively* Detector signals were processed by an ADC coupled through a CAMAC buffer memory to the PDF - 11/70 computer. The following elements were determined: NA,MN,FE,CD,SE,CO,CA,BR.For the treatment of the data obtained duster analysis was applied/ 1 /. DISCUSSION After applying the duster analysis to the cases investigated they were divided into two clusters.Each of olUBters thus formed is characterised by the following concentrations of the elements in the concretions/table 1/: Table 1. H MB Fe Co Cd Se la Ca/103 Br I. 2.0+0 .5 7B+6.5 0.41+0.1 4.4+0.8 0.4+0.1 3200+760 258+17 5.8+1.2 II. 16.8+6 .4 1340*460 4.2*1.7 32+12 2.4+1 3560+870 267+20 13.7+4.3 From the results presented in table 1 it can be seen that the clusters differ one from otner in the content of tne elements MN,PE,CO,CD,SE.The cluster I consists of cases with low content of the mentioned elements,the cluster II contains cases with high content of the same elements. The dusters were compared with tho available clinical findings. On the fig.1 is demonstrated the correlation creatlnin - urea for the renal calculi of the female patients from both olusters( 1 - cases from clus- ter I, 2 - oases from duster II). A tendency oan be observed to a shar- per increase of creatinin with the increase of urea for the cases with high concentration of the elements of interest. CONCLUSION The number of tne oases analysed is not sufficient to draw some conclusi- ons .However the results obtained show that the processes leading to the nucleation obviously proceed in such way that they result in a forma- . tion of two kinds of renal calculi - with low and high concentrations of some elements .For further investigations from our point of view it will be of interest to analyse only surface layers of the concretions which could pos- sibly have some connection to the clinical findings, characterising tht patients condition/ 2 /, It also should be cleared if the difference in the content of the stones from both clusters is due to the different types of the concre- tions, or to some physiological reasons, or is a result of the influence of the pollution in the environment .In case that the main reason for the observed differences is the environmental pollution than the concre- tions could be uBed as a speoific monitors for the Btate of the environment* 86 3 6 UREA/(mg%) pig. 1 REFERENCES /1/ B1I0F - Programme Statistical Developement,University of California, Los-Angeles-London, 1979* /2/ B.E.TaylorfS.A.Saied, British Journal of Uro logy (19B2),5£, 346 - 347 87 DETERMINATION OF SODIUM IN PHARMACEUTICALS BY NEUTRON ACTIVATION ANALYSIS G.D. Kanias*and N.H. Choulis** *Radioanalytical Laboratory, Chemistry department Nuclear Research Center "Demokritos", Aghia Paraskevi Attikis, Athens, Greece ""Laboratory of Pharmaceutical Technology, University of Athens, 104 Solonos str., Athens, Greece INTRODUCTION The chemical element sodium exists in all the pharmaceutical preparations either in active compounds or in excipients or both. The active compound in a large number of drugs is usually present in the form of its sodium salt because this form gives high solubility of the active compound in water e.g. injectables, oral solutions. Different sodium salts are added as excipients during the formulation of the pharmaceutical dosage form such as: sodium alginate for granulation and disinte- gration, sodium benzoate for preservation, sodium chloride for dilution and lubri- cation, etc. The total concentration of sodium is included in the list of specifications of some pharmaceutical products e.g. Pentothal in injection dosage form (1). The knowledge of sodium content in Pharmaceuticals is important because when this element belongs to the molecule of the active compound and/or the excipient, the estimation of its content controls directly or indirectly the: identity, strength, quality and purity of the drug in which sodium is found. Also when heart patients are treated with diuretic and cardiotonic drugs a continuous control of sodium content in those drugs is needed because it is known that sodium is related with diuresis (2). Nuclear analytical techniques (neutron activation analysis) have not been utilized extensively in the pharmaceutical analysis although they have some advan- tages over the conventional methods. Literature shows only few applications of neutron activation analysis in the control of active compounds in drugs (2,3,4,5,6). To the best of our knowledge the determination of sodium in drugs for the control of active compounds by neutron activation analysis has not been studied up to now. It must be pointed out that all pharmaceutical dosage forms do not offer themselves for the determination of active compound through sodium content, because this element is found almost in all the solid excipients. Thus, only the dosage forms which contain tridistilled water as unique excipient, (except eye-drops) could be investigated. The purpose of this work is to develop a simple, fast and accurate method for the determination of sodium in pharmaceutical preparations concerning either the determination of active compound or the total content of this element. The examined dosage forms consisted of injectable and oral solutions and the applied method was instrumental neutron activation analysis. EXPERIMENTAL Apparatus The irradiation of samples and standards was carried out using the rotation system of the reactor of Nuclear Research Center Demokritos with a maximum thermal neutron flux of 2.9'K)13n«cm-2«sec-1. Gamma-ray spectrometry of the irradiated samples and standards was accomplished with a coaxial Ge(Li) detector series Winib with an efficiency of 15% connected to an Ino-Tech 1024 channel analyzer (Model IT 5200). 88 Sampling Samples for analysis were selected from the Greek Market. The number of collected and analysed samples were 10 ampoules for injection and 10 bottles con- taining oral solution. These were classified according to the dosage form and according to the active compound to be determined and in each sample a code number was assigned. Each ampoule for injection, bottle with oral solution, was opened and the required volume was withdrawn for analysis. Standards for analysis The appropriate amount of analytical grade purity NaN03 was dissolved in tridistilled water for the preparation of a standard stock solution containing sodium in a concentration of 40 mg/ml. Different dilutions of this standard were used for the analyses. Procedure For the determination of sodium in drugs 0.7 ml of sample with an equivalent volume of sodium standard solution of analogous concentration were placed into 1 ml polyethylene vials which were heat-sealed for irradiation. Samples and stan- dards were irradiated simultaneously at the rotation system of the reactor for 5 minutes. The thermal neutron flux was S.S.'IO11n«cm"2*sec"1 for sample under the RESULTS AND DISCUSSION The results obtained from the determination of sodium in different pharma- ceutical dosage forms by neutron activation analysis are summarized in Table i. In the column "element found by NAA" the mean value from the analysis of 10 different samples of each drug product is given. TABLE 1 Results of sodium determination in different drugs Code Dosage form Composition per dosage form Na calculated Na found Percent label Number from label by N.A.A. claim based claim (ing) (ing) on Na found 1 Injection 1 ml Metampyrone 1000 mg/2 ml 65.0 63.5 97.7 2 Injection 5 ml Pitophenone HC1 Fenpipramide methylbromate Metampyrone 2500 mg/5 ml 163 161 98.8 3 Oral solution Metampyrone 500 mg/ml 32.6 32.8 100 4 Oral solution Pitophenone HC1 Fenpipramide methylbromate Metampyrone 500 mg/ml 32.6 32.7 100 5 Oral solution Sodium dipropylacetate 27.6 27.8 101 200 mg/ml 6 Oral solution Sodium picosulfate 7.5 mg/ml 0.716 0.694 96.8 The sensitivity of neutron activation analysis for the determined element under the experimental cqnditions of this work is 40 ug. Table 2 shows the precision and the accuracy achieved in the determination of sodium in drugs by neutron activation analysis. 89 TABLE 2 Precision and accuracy of sodium determination in drugs Code number Standard deviation Standard error of drug (*) 1 3.1 2.3 2 1.0 1.2 3 1.9 0.6 4 2.5 0.3 5 2.8 0.7 6 2.9 3.2 As it can been seen in Table 1 the pharmaceutical products with code numbers 2 and 4 besides sodium contain two other active compounds with the elements chlo- rine and bromine respectively. Normally it was expected that an indirect determi- nation of all three active compounds could be done with one irradiation. But pre- liminary experiments showed that the radioactivity of sodium was so high, thus not allowing the determination of the other two active compounds with the proposed very simple and fast method of analysis. The rapidity of the developed method for sodium depends on the thermal neutron flux and the cooling time. One hour's cool- ing time and two different thermal neutron fluxes were chosen for this work. The choice of these experimental conditions was based on the calculated sodium content in the examined drugs and on the purpose of irradiating simultaneously big numbers of different samples (from 8 to 50). A pneumatic transfer system (rabbit) could also be used for the determination of sodium in drugs but this way of irradiation, although faster than the proposed one it does not offer the advantage of simultaneous irradiation of big numbers of samples. The obtained results of this work as well as those reported in the litera- ture (1,2) showed that neutron activation analysis is a very fast and simple method for the determination of sodium in pharmaceutical preparations, whether this deter- mination concerns the estimation of active compound or the total content of this element. The accuracy and the precision of the applied method are found to be very high and therefore this method could be established as an official one.for the determination of sodium in pharmaceutical preparations. REFERENCES 1. G.D. KANIAS. J. Radioanal. Chem., 60 (1980) 237. 2. G.D. KANIAS, N.H. CHOULIS. J. Radioanal. & Nucl. Chem. Articles 88/2 (1985) 281. 3. A.O. PEDERSEN, E. STEINNES, T. WAALER. Medd. Norsk. Farm. Selsk 30 (1968) 41. 4. V. HOLM, E. STEINNES, T. WAALER, Medd. Norsk, Farm. Selsk. 30 (1968) 17. 5. J.P.F. LAMBERT, M. MARGOSIS, J. Pharm. Sci. 59 (1970) 1005. 6. M. MARGOSIS, J.P.F. LAMBERT, J. Pharm. Sci. 60 (1971) 592. INVESTIGATION OF DISTRIBUTION OF ZINC, IRON AND Quantitative determination: Comparaison method and TPA - ANTIMONY IN HEALTHY AND PATHOLOGICALLY ALTERED treatement. The results are presented as partial and total contents of elements ( eg - and C^- parameters ) expressed LIVER TISSUES in nKg / g of liophilyzed tissues with statistical, parameters SD, SE and CV . K. Kostic, S. Stankovic Medical Faculty, Laboratory for Application of RESULTS AND DISCUSSION Radioisotopes in Medicine 11000 Beograd, Yugoslavia The Tables 1 and 2 present the data on eg - and Cp- parameters in healthy R.J. Draskovic liver and in H - and CA - tissues of the liver with primary CA. Boris Kidric Institute of Nuclear Sciences - Vinca POB 522, 11000 Beograd, Yugoslavia INTRODUCTION ELEMENTS C SD SE CV Contents of some elements in human organs and tissues often depend on di- E fferent pathological processes ( 1 - 5 ). This phenomenon suggests specific nKg / g % role of TRACE ELEMENTS in metabolic disorders during the progress of disea - ses. Data on elements'qualitative and quantitative distribution in healthy and pathologically altered tissues and organs can be used as a basis for investigation of this role in such processes. IRON 1)1)1 36.1) 7.5 8.2 In recent studies of the role of trace elements enabled conditions for development of a new scientific discipline - MEDfCAL ELEHENTOLOGY.* ZINC 351* 20.1) U.I 5.8 in this paper, we present the results of our studies of distributions of iron, zinc and antimony in healthy tissue, different pathological structures ANTIMONY 0.03 0.1 0.02 20.1 of cirrhotic liver, cirrhosis associated with evoluted carcinoma and primary carcinoma of human livers, using INAA as analytical method. The aim of our work is to demonstrate changes of the contents of some ele- ments as a function of tissues'pathological alterations in different disea - TABLE 1. TOTAL MEAN CONTENTS OF ELEMENTS ( Cp ) OF IRON, ZINC ses of 1iver. AND ANTIMONY IN HEALTHY LIVER EXPERIMENTAL Liy.er samples were taken during authopsy. Diaonosae: based on histopathological findings. ELEMENTS LIVER C SD SE CV Analyzed liver samples: healthy; cirrhotic with primary CA F and cirrhotic associated with primary evoluted CA. TISSUES nKg / g * Analyzed tissues: healthy liver ( different parts of the left and right lobus ); cirrhotic liver ( hepatocites - HC ; regenerative nodes - RN ; fibrous tissues - FT ) ; liver with H 683 99.6 IRON 199 29 primary CA ( tumorous nodes - CA ; healthy tissues - H ) ; CA 1)61 22.7 8 cirrhotic liver associated with primary evoluted CA ( hepa - 1)5 9. h tocites - HC ; regenerative nodes - RN ; tumorous tissue - CA ). ZINC H 371) 15 7.6 Liophilyzation: in Leubold - Hereus GT - 2 apparatus at a pressure CA 63 11 5.6 17.6 2 of 5.30 Pa ( i» x 10" Torr ) and T = 258° K ( - 15° C ). 0. .0 Sb: on Analysis for Qualitative and Quantitative Investigations of Liver Tissues, Mr - thesis ( in preparation ) relations of C_- parameters for RN -, HC - and CA- •-RN SB: C RN CHC -CA relations of c_ - parameters for H- and CA- tissues of liver with primary carcinoma are: Fe: cu > crll Zn: CH > cCA Sb: cH > ccfl ( liver 1 ) cH Uver2 CONCLUSION Results of our investigations indicate significant differences in investi gated elements ( Fe, Zn, Sb ) in healthy and pathological livers as well as in different structures of cirrhotic liver, cirrhotic liver associated with CA and tumorous liver ( CA ). REFERENCES /I/ Kostic K., Draskovic R.J., Djordjevic H.,Ratkovic M.,Kostic D.,Cvetoje- vic - Savic M., Draskovic R.S., Iron, Cobalt and Zinc Contents in No - rmal and and Pathologically Altered Liver Tissues; Proceeding on Bad Ga- steiner Internationales Symposium, Bad Gastein, Austria ( 1976 ),pp.l65 - 173 92 THE INFLUENCE OF SOME ADDITIVES TO THE HIGHLY CARBOHYDRATE DIET ON THE DISTHIBUTION OF Al, Ca, Cl, Mg, Mn, AND Na IN TEETH ENAMEL AND F"NES OF EXPERIMENTAL ANIMALS P.Bakyrdschiev Stomatological Faculty, Academy of Medical Sciences, Sofia,Bulgaria I.Kuleff Faculty of Chemistry, University of Sofia, 1.126-Sofia, Bulgaria E.Djulgerova Stomatological Faculty, Academy o f Medical Sciences,Sofia,Bulgaria M,Iovtschev Institute of Nuclear Research and Nuclear Energy,1184-Sofia,Bulgaria Diets with different suit and permanent basic composition play important role in the friquency and intensity of thejexperimental caries /i/. The disbalance of tne microelements in the organism at carbohydrate diets leads to disturbance of tne metabolism and redistribution of the microelements in the different organs and tissus. Extremely sensitive to these changes are the highly mineralized tissues, bones and teeth. The application of experimental diets with high carbo- hydrate composition and sharp protein deficiency puts the experimental animals at such conditions /<;/. The processes of demineralization and remineralization may develop with different rate depending on the microcomponent composition of the tissues /j/. The data about the influence of the microelements and the changes of their concentrations of such conditions are still not enough /h/. In an earlier paper /5/ the dependence of Mg distribution in teeth enamel and mandibula on the additives to the diet has been shown. As a further continuation this investigation aims to follow the changes in the concentration of Al,Ca,Cl,Mg and Na at using diets with high carbohydrate composition and MgCl» and methylene blue additives. Three groups of animals Wistar, Hamster and S.Dawley with different reacti- vity from genetic point of view have been used. Each group was divided to four subgroups. The basic diet was modified Keyes-2000 /i,6/. The first subgroup of animals was a control group feeding on normal diet. Two of the groups were given water to wich MgCJ.,, and methylene blue has been added. The forth group was feeding on tne same lieyes diet but without additives. In each subgroup were 10 animals. The experiment was carried out for 45 days. All experimental animals were fed on adlibidum. After killing the animals teeth enamel, mandibula and tibia have been sampled. After homogenization of the samples in agate mortar, the content of Al,Ca,Mg, Mn and Na and 01 was determined by INAA. The samples were irradiated for \ min. in the rabbit system of the experimental nuclear IRT-2000 /6/ after which were measu- red twice. The first measurement was carried out after a cooling time of 1 min. for tUe determination of Al,Ca,Cl,Mg and the secbnd - after 2 h cooling time -for Na and Mn, The precision of the analysis was between k and 12 H>. The data from the analysis were subjected to analysis of variance and the results were as follows: 1.The diet and its additives influence the microelements content in the animal groups in different ways. 2.Na and Al contents in the bones and tooth enamel are not influenced by the diet and additives. 3.The content of Ca is also practically unchanged. The only exception is its decrease in the mandibula of Wistar and S.Dawley when methylene blue is added. ON THE CONTENT OP SODIUM, POTASSIUM, MAGNESIUM, CALCIUM AND CHLORINE IN ORGANS OF WISTAR RATS M. Iovtchev, L. Kinova, T. Grigorov, D. Apostolov Institute of Nuclear Research and Nuclear Energy Boul. Lenin 72, 1184 Sofia, Bulgaria Z. Kemileva Academy of Medical Sciences G. Sofiiski Str.5, Sofia, Bulgaria INTRODUCTION The role and the significance of the elements Na, K, Mg, Ca - marked in the special literature as electrolytes - are investigated in the biological processes from different aspects. Usually along with them is investigated the participation of Cl since it enters in the organism mainly with those elements and could be found in all organs and body fluids. The purpose of the present work is to determine the content of the men- tioned elements in heart (H), kidney (R), liver (L), small (SI) and large (LI) intestines of normal (intact) and thymectomized (after elimination of the thymus gland) WISTAR rats at different age and duration of postoperative pe- riod. It presents interest because of the pathological changes in the organism after tho thymectomy - hypertrophy of the heart muscle, related to the hyper- tension observed in rats after thymectomy /1-4/. EXPERIMENTAL Investigated were male WISTAR rats at the age up to 12 month : 80 intact (control group Wi) and 80 thymectomized (W+), receiving during the experiment standard food. After the extirpation the organs from the kind and age are united, washed with bide at. B^O (30 min. in 4x0.51), homogenized and lyophilized /5/, The investigation was carri- ed out by means of INAA. The samples were activated in a 112 neutron flux with $ 55<1O n/cm?seo.(IRT 2000 - Sofia) and measured on Ge/li-detec- tor (resolution 2.3keV at i332keV of60 Co) with decay time 120sec. (Kg, Cl, Oa) and 2 h (Na, K), The stan- dards were aliquots of solu- tions with suitable concen- trations and also used was BOWSN*s kale. • - Klteey (l) o - Uvtr (L) DISCUSSION x «• InH (II The analytical procedure A • IHU labttlBM is conventionalized reasona- bly to ensure the reproduci- bility of the experiment and minimize the possibility of random errors. The results (ppm dry weight) for the se- parate experimental points are compared by the STUDENTS test (confidential interval 95 %). SODIUM The results differ significan- tly for both groups (exception H). W.i General decrease of the concentration with the age for X and SI; maximum at 1.1- 6 and 9 month for H,R,LI. Wti The concentration increase after 3 month. POTASSIUM Higher absolute values in com- parison with Na. W.: The tendency follous the behavior of Na. Wt: Increase of the concentra- O.f. tion (H and L), for the rest organs the differen- ces are not significant. 0.1 MAGNESIUM W±: Age tendencies as for Na and K (exceptions: L, whe- re concentration is rela- tively constant; R - in- crease at 12 month). (81) Wt: Relatively slight change FI0.2i w /w -**tt* of tto Ctf of the concentration with t % the age (exception 11 - with a strong maximum at of ffXSf Aft r»«i 9 month). CALCIUM Wji There is no clear tenden- cy with the age. In H and R the concentrations axe relatively constant. Wtt Sharp increase of the con- centration in all organs 1.5- analysed at the age of 3 month. At the next term analysed a slow decrease of the Ca content is ob- served. 1.4 CHLORINE The results for both groups follow generaly the Na tenden- cy. W.: There is no significant 0.9 difference in the concent tration values after 6 month. Aft (Mfttlu) Wt: A significant difference 0. is observed only for L It and SI. The results for large intesti- nes LI are most varying for all elements. 11 B8 UtttlMt The changes in the concentra- tions of the elements determi- ned in organs of thymectomized t«f»tl«M in rats can be followed by compa- rison of both groups W.. and W+ •t tin a 95 / For Mg (Fig.7) are observed comparatively small devia^ tions in the ratio W./W.. For the rest of the elements the utmost deviations are ob- served for 3 month (first term after thymectomy), as it is for calcium (Fig.2), where con centrations in W.are much higher, than in W^. For Cl (Fig.3) the concentrations in W^ for 3 month are much lower, than in W±. All elements investigated show a tendency to approach normal concentration values at the age of 12 month. The ratio of the elements for both groups (W^ versus W^) and different ages could illustra- te the alterations of the electrolyte balance of the or- ganism. In the ratio. Na/K no changes are observed with the age in the W which correspond to • - EUMf .(•) it o • U*W (fc) the physiological balance of X - iMUPt (HI both elements in the organism. The ratio Na/K behaves in the A- ami u same way in the group of thy- mectomized rats W. (exception R - first term after thymecto- my). In W^ vs. Wt there is a tendency to equalization at., the age 12 month of the ratio Na/K for the most of the or- gans analysed after thymectomy (Fig.4). CONCLUSION The concentrations of the determined elements in the group W^ (intact WISTAR rats) follow a common tendency in the investigated age periods. Esta- blished are changes in the concentrations for thymectomized rats (Wt) in the first term after thymectomy. The observed tendency to level with the normal va- lues for the concentrations of the elements in thymectomized rats could be ex- plained with the ability of the organism for adaptation and recovery of essen- tial functions in the absence of an important enzyme regulator - the thymus gland. REFERENCES /I/. Z. Kemileva : Thymus , Hedicina i fisoultura, Sofia 1979 12/. Z. Kemileva, M. Balucov: Compt. Rend. Acad. Sci. Bulg., 29 (1976) 1849 /3/. P. Deschaux, et al.: Canad. J. Physiol. Pharmacol., £2 (1975) 501 /4/. A. Gray: Clinical Pathology , Oxford 1966 /5/. L. Kinova, M. Iovtchev, T. Grigorov, D. Apostolov, Z. Kemileva: Proc. 3. Tagung Nukleare Analyseverfahren, 11.-15*04.1983, Dresden, DDR ENVIRONMENT 99 INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS IN ENVIRONMENTAL RESEARCH M. de Bruin Interuniversity Reactor Institute Mekelweg 15', 2629 JB Delft,The Netherlands INTRODUCTION The introduction of Ge-semiconductordetectors and laboratory computers hao strongly stimulated the development of neutron activation analysis (NAA) over the past two decades. The high energy resolution of Ge(Li)-detectors and apparently unlimited computing facilities made chemical separations superfluous for many sample materials (1). The detection limits are not as low as obtained when applying chemical separation,but in many types of samples such as geological materials,soils,air particulates,refuses.industrial wastes and plant materials,tens of elements can be determined simultaneously by a purely instrumental technique. Instrumental neutron activation analysis (INAA) is very well suited for application in environmental research and monitoring. It has been discussed extensively in literature (2) and at meetings such as the IAEA symposium "Measurement,Detection and Control of Environmental Pollutants" held in 1975 (3) and the five consecutive conferences on "Nuclear Methods in Environmental and Energy Research", organized by the ANS. In his contribution at the most recent of these conferences (Mayaguez, Puerto Rico, 1984) Steinnes (.4) stressed the pertaining importance of nuclear analytical techniques in environmental research along with other techniques such as atomic absorption spectrometry and emission spectroscopy. The advantages of neutron activation analysis in general have been discussed recently by Greenberg (5). The characteristics of instrumental NAA when applied to environmental samples can be summarized as - high sensitivity for many relevant elements - high accuracy for a variety of sample types - insensitive for light elements - information on many elements simultaneously - economically attractive. These characteristics are discussed in more detail in the next section. At Delft, INAA is used in a variety of environmental research projects. A description of the IRI system for INAA will be given,with some recent results obtained in monitoring heavy metal air pollution using lichens. Finally,some ideas will be presented regarding the position of INAA in environmental research and monitoring in the near future. CHARACTERISTICS OF INAA, RELEVANT FOR ENVIRONMENTAL APPLICATIONS Sensitivity Although lower than what is achievable by radiochemical NAA,the sensitivity of INAA is still such that many (potentially) toxic elements can be detected in the environment far below detrimental concentration levels. Therefore,the behaviour of such elements in the environrr t can be studied often at natural concentration levels. When using INAA in environmental monitc ig, increases of heavy metal concentration levels can be observed -and the necessary measures e taken- long before they have developed into an accute environmental problem. This is illustrated by the detection limits of INAA for some elements in air filters,and the maximum permissable ion mission concentrations (MIC-value) for these elements,presented in Table I. The filters im- (cellulose, 5 cm2,10 m3 of air) were analysed with the IRI-system for INAA which will be discussed in the next section. Be and Fb are the only elements of environmental concern to which INAA is not applicable: the determination of lead using Z07mPb is regarded as inadequate when compared to the determination by AAS. Aoauraoy The low risks of contamination of element loss, typical for NAA, are particularly important in the analysis of environmental samples,where the concentrations of interest are mostly in the ppb- to ppm-range. Equally important is the lack of matrix effects for a large range of matrix compositions. This makes it possible to obtain absolute and directly comparable concentration values for strongly differing materials such as surface water,air particulate matter,human and animal tissues,plant materials and soils. In addition,when using INAA, no destruction or chemical separations are applied,so that post-irradiation losses are avoided. These factors are the basis of the high accuracy obtainable with NAA, reflected in the dominating role of this analytical technique in establishing certified coneputrations of trace elements in reference materials (6,7). Insensitivity for light elements Of most light elements the thermal neutron cross-sections are very low,or the reactions lead to nuclides with very short half lives. Even when present at high concentrations, elements such as H,C,N,O,(Al,)P,S,Si and Ca do not interfere in the INAA procedure, neither directly by the induced activity or inuirectly through neutron flux depression or self-shielding. As these elements are the major constituents of water, tissues,soils and filter materials, they are apparently absent in the analysis and do not hamper the detection of the heavier elements present at trace level. The major light element interference is due to zltNa,the neutron activation product of oodium. The high concentrations of this element in most human and animal tissues or fluids and 100 sea materials severly limit the sensitivity for elements determined on basis of nuclides with intermediate half lives. For certain elements, the use of a nuclide with short or long half life as alternative for an otherwise more sensitive nuclide with intermediate half life, may lead to improved detectability. For example,the detection limit of Cu in toenails when measuring 61|Cu (12.7h) is approximately 10 ppm because of the high zl*Na-activity; when using 66Cu (5.1h),the detection limit is lowered by a factor of 10 to less than 1 ppm. Self-evidently,high sodium contents such as present in whole blood,do not affect analyses using nuclides with long half lives (8). Limitations due to 21tNa can be avoided also by applying a hybrid of radiochemical and instrumental NAA, where the Na is selectively separated using hydrated antimony pentoxide 19). But this approach is relatively laboreous and the accuracy may be affected by losses in the chemical procedure. Multi-e Lement capability The large number of elements determined simultaneously in an INAA-procedure is becoming increasingly important for many environmental applications. As it is often not known a priori which elements are matter of concern in a certain area,a "broad spectrum" analysis covering a large part of the Periodic Table,is of the first importance for environmental monitoring. In this respect, INAA is very suitable as it yields information on all (potentially) toxic elements except Be and Pb,when present at relevant levels. Part of the information obtained refers to elements which are not of direct environmental concern. This additional information may play an essential role in the interpretation of the toxic element concentration data. As elements such as As and Sb are present in natural soils at ppm levels, it is important to distinguish between the "natural" amounts of these elements originating from that soil and the amounts from anthropogenic sources. Normalization of the observed concentrations on basis of the concentrations in the same sample of selected reference elements characteristic for soil (Al,Sc,Fe,R.E.) yields an Enrichment Factor (12) which allows to discriminate between these possible sources. Possibly the most important application of the multi-element information obtained from INAA is the use of trace element patterns as fingerprints for identifying specific sources of inorganic pollutants. The basic idea is that the elements of primary interest are introduced into ,the environment in specific combinations with other elements, and that certain elements or element ratios are specific for different sources. Identifications of sources of pollutants on basis of element patterns of environmental samples mostly regard the elucidation of the origin of inorganic air pollution using the element concentration patterns observed in air filters. But applications have been reported also for other materials such 4s lichens used as biological indicator for pollution with heavy metals (13,14). In the identification procedures reportedvtwo basically different approaches can be distinguished. When the relevant sources and the compositions of the associated emissions are known,the "Chemical Element Balance" method can be used to estimate the relative contributions of each of these sources at a specific place or in a specific sample (15,16). When applying Factor Analyses procedures,a set of hypothetical components is calculated from the compositions of a large number of samples, without using a priori knowledge of actual sources or compositions. These hypothetical components can then be identified with realistic components or sources on basis of their calculated element concentration patterns. The Factor Analysis approach has been discussed thoroughly by Hopke (.17); Chemical Element Balance and the Factor analyses methods were evaluated recently by Stevens (18). Analysis costs In environmental research and particularly in environmental monitoring, large numbers of samples and analyses are involved. Therefore, cost per analysis will be an important factor when judging the value of a specific analysis technique for such applications. INAA is often regarded as a complicated and expensive analysis technique,to be carried out by high level specialists. But since it is a purely instrumental technique, automation and computerization are possible to a high degree. At present,the capacity of laboratory compurers is such that their use for automated measurement,spectrum analysis and interpretation,and administration may reduce considerably both amount and level of labor involved in INM. Although the resulting savings in analysis costs will depend on local conditions such as the ratio between labor- and instrumentation/computer-costs.it will in general lead to appreciable cost reductions. For the system for routine INAA in use at IRI.the costs are DF1 125-200 ($35-50) for a complete analysis involving two irradiations and three measurements (19). This is comparable to or even lower than the costs of the alternatives, which often include laboreous and costly chemical manipulations. THE IRI SYSTEM FOR ROUTINE INAA Description of the system The analysis system 120) is based on the use of the single comparator method of standardization (21) to take full advantage of the multi-element capabilities of INAA without the problems associated with the preparation and use of trace element standards covering two thirds of the periodic system. Zinc is used as mono-element standard; the element concentrations are calculated on basis of a weighed average of the 65Zn- and 69mZn-activities,using experimentally determined conversion factors. The analyses are. performed according to a standard protocol comprising a first irradiation of 15-30 s followed by a measurement after 0.5-20 tn decay,and a second irradiation of O.5--4 h followed by too measurements after 2-6 d and 3-5 w respectively. The irradiations are^carried out in the Institute's 2Mw swimming pool reactor in a thermal neptron flux of 1 x 10 "n/cro .s.. 101 The irradiation facilities used are a fast rabbit system (transport time <3 5 s) for short irradiations and a slow rabbit system (transport time 8 s) for the long irradiations. The spectrometers,equipped with coaxial and well-type Ge(Li)-detectors are integrated with a DEC PDP-11/44 computer through buffered input gates in a CAMAC interface system (Fig. 1). The well-type detectors are expensive but have the advantage of a high photopeak efficiency (5-50% , depending on yray energy),so that good detection limits are obtained even after an irradiation of a few hours at a moderate neutron flux. PULSE OCTECTOR GENERATOR AMPLIFIER CAMAC ADC •COMPUTER ~L BUFFER TIMER CONTROL CLOU Fig. 1. spectrometer used in INAA The y-v&y spectra are converted into element concentrations using a set of dedicated computer programs (22,23). The INAA software package comprises the following main functions: - spectrum analysis and interpretation,including conversion of the peak area data into element concentrations or estimated upper concentration limits. The isotope identification is based on a catalog of measured y-ray energies and intensities (24); - comparison and combination of the intermediate results obtained from measurements after different decay times, correction for blank and for contributions from interfering reactions; - generation of the final analysis report in hard copy or on tape or disk; -^bookkeeping of the results obtained from reference materials for detection of systematic errors in the analytical procedure. The results obtained in repeated analyses of reference materials indicate that the accuracy of the method is in general better than ± 5%,which is adequate for most environmental samples. Table I shows some detection limits obtained routinely in materials of environmental interest. Table I. Routine INAA at IRI Element Detection limit MIC-value air in air (25) soil plants nails/hair particulates (ng/m3) (ppm) (ppm) (ppm) (ng/m3) V 3 1 1 1 250 Cr 1 1 0.3 1 100 Mn 1 I 1 1 25000 Fe 100 30 30 100 5000 Zn 10 1 1 10 10000 As 1 0.1 0.03 0.1 50U Se 3 1 0.3 1 — Cd 1 1 0.3 1 500 Sb 0.3 0.1 0.01 1 2500 Hg 3 1 0.3 1 10 Environmental applications of the INAA system Currently, more than half of the 4000 samples analyzed annually are related to studies of the transport of heavy metals in the environment. In these applications, the multi-element capabilities of INAA are essential, either to study a range of heavy elements simultaneously, or for source identification on basis of trace element patterns. Major projects are: -identification of sources of heavy metal air pollution using air filters or biological 102 indicators such as mosses and lichens. The air filter daia are interpreted by correlation with meterological data and by Factor analysis. The studies using lichens are discussed in some detail in the next paragraph; - study of the uptake and translocation of heavy elements in plants. This study involves plants grown in actually polluted areas as well as plants grown under controlled conditions at the laboratory. In a complementary approach, trace element transport kinetics are studied in isolated plant parts with fadionuclides of 15 elements simultaneously (26). A separate study is aimed at evaluating the use of selected plant species for "biological cleaning" of soils polluted with cadmium; - evaluation of human toe-nails as an indicator of heavy metal uptake by populations in polluted areas. This study is combined with a survey using lichens in the same area; - evaluation of bird feathers (27),mollusks and waterplants as possible indicators for heavy metal pollution in fresh water and estuarine areas. Part of the studies are carried out in cooperation with chemists,physicists and biologists from Dutch universities. USE OF LICHENS AS BIOLOGICAL MONITOR FOR HEAVY METAL AIR POLLUTION Introduction The major part of our effort in environmental research is focussed on the development, evaluation and application of epiphytic lichens as accumulating monitor for identifying sources of heavy metal air pollution. Various plant species have been used for such monitoring, especially in Scandinavia, Great-Brittain, Ireland and Canada (28,29,30,31), but the results have to be handled carefully to avoid misleading conclusions (32). Therefore, special attention is paid to mathematical techniques for a reliable interpretation of the element concentration patterns observed in sets of lichen samples. In air pollution surveys, epiphytic lichens are collected at places regularly spread over an area under investigation. At the laboratory, the lichens are separated from the substrate bark, washed, dried and analyzed by routine INAA. In Table II, ranges and mean values are listed of element concentrations found in material collected in De Kempen, an industrialized area in the South of The Netherlands. Besides mapping of the element concentrations, two additional procedures are applied to the concentration data, to obtain information on position and identity of any significanc sources present in an area: - mapping of the concentrations of individual elements after conversion to Enrichment Factors; - application of Factor Analysis to the multi-element dataset and identification of sources of pollution and their contributions for each relevant element. The relevance of carefull data interpretation will be illustrated below with some of the results from two recent air pollution surveys in The Netherlands. The first survey covered the entire country, the second one was focussed on De Kempen, a small area along the Southern border (Fig. 2a), known to be polluted by heavy metals. Table II. Trace elements in Lecanora conizaeoi El. av.cone. range el. av.con. range el. av.con. range ppm ppm ppm ppm ppm ppm Na 680 200-1900 Fe 6100 1700-1700 Eu 0.15 0.052-0.40 Mg 1480 420-5100 Co 4.9 1.4-23 Dy 0.49 0.19 -1.1 Al 5200 1900-11000 Zn 590 120-7500 Yb 0.31 0.055-0.97 Cl 680 290-1200 As 11 2.4-41 Lu 0.057 0.011-0.20 K 4300 1400-11000 Se 2.5 0.80-8.1 Hf 1.0 0.25 -3.2 Sc 1.5 0.42-4.2 Br 50 7.5-140 W 1.3 0.25 -12 Ti 420 100-4300 Cd 5.0 1.0-33 Au 0.012 0.003-0.091 V 29 12-76 3b 13 3.4-61 Hg 0.98 0.20 -13 Cr 30 9.7-88 La 4.4 1.3-12 Th 1.1 0.32 -2.6 Mn 97 43-175 Ce 8.3 2.8-22 U 0.56 0.13 -1.9 Application of Enrichment Factors Our experiences so far indicate that straightforward Reographical mappinc of concentrations of individual elements and locating sources on basis of concentration gradients does not yield reliable results. Local differences in growing conditions of the lichens may lead to artifacts not related to the factors studied. Conversion of element concentrations into Enrichment FactorB improves this situation as this conversion implies correction for differences in soil contribution or growth rate. The Enrichment Factor of an element x on basis of a reference element y is defined as: Cx EF = ^Cy*lichen In our studies, the Enrichment Factors are calculated with scandium as reference element, using the element-scandium ratios experimentally determined for "clean" Dutch soils. Fig. 2a and b show maps of the arsenic concentrations and arsenic Enrichment Factors of Parmelia 103 Pormelio Sulcolo Potmelio Sulcolo At-concentroli (ppml Fig. 2. Distribution over The Netherlands of arsenic in lichens and the average atmospheric S02~concentration. K = De Kerapen sulcata collected over the country. The first map shows a concentration gradient towards the South-Western border, suggesting a major source of arsenic in that direction. The arsenic Enrichment Factor however has a rather flat distribution. This suggests that the high As-content is due to locally high soil contributions, or that the arsenic is emitted together with soil elements in a natural ratio. Fig. 2c represents the distribution of the atmospheric SC>2-concentrations over the country. The similarity between the SO2- and the arsenic-distributions suggest either a common source of the two (e.g. coal burning), or a casual relationship between the two concentrations. Influence of the atmospheric S02~concentrations on trace element concentrations in lichens is not unlikely since high S02~concentrations are known to inhibit lichen growth (33). It will be clear from this example that one has to be very carefull with conclusions based only on concentrations of single elements. Application of Factor Analysis Dc Kempen is an area along the Dutch-Belgian border which has been for a long time, and still is, polluted by emissions from metallurgical industries. Several zinc smelters have been in operation for more than a century and the area also houses a branch of a large electronic industry. Part of the zinc smelters have changed their production process recently to reduce heavy metal emission. Contributions to the air pollution can also be expected from the center of industrial activities around Antwerp, appr. 50 km in Westerly direction (fig. 3). Antwerp 50 km Fig. 3. The 20 x 50 km area surveyed in De Kempen. o = zinc smelter; x = electronic industry The lichen Lecanora conizaeoides was collected in an area of 20 x 50 km at in total 140 sampling points positioned on a lath of 3 x 3 km. Factor Analysis was applied to the element concentration dataset, using the information on 17 elements: Al, K, Sc, V, Cr, Mn, Fe, Co, Zn, As, Se, Br, Cd, Sb, Eu, W and Th. The Factor Analysis procedure yielded 5 factors or hypothetical components, accounting in total for more than 85% of the variance present in the dataset. The normalized 104 elemental compositions of these components are listed in Table III. Table III. Results of Factor Analysis Factor composition Element factor 1 factor 2 factor 3 factor 4 factor 5 Cd 4.7 1000 As 1.5 210 3.6 Sb 2.9 310 4.2 Zn 1000 Al 940 320 K 540 Se 0.25 0.24 V 6.6 Cr 2.9 5.7 Mn 17 6.1 Fe 1000 1000 Co 1.5 0.67 71 Se 0.37 30 0.66 Br 1000 Eu 0.01 0.02 W 800 Th 0.15 0.17 Factors 1 and 2 can be identified with contributions from the soil, either separated artificially into two components, or representing two real soil components. Factor 3 consists ofi a group of volatile elements, originating from high temperature industrial processes, including coal burning and refuse incineration, and from automobile exhaust (Br). Factor 4, with a characteristic Zn/Cd-ratio of appr. 200, is associated with zinc ore processing. Factor 5 does not reflect a typical emission pattern, but the cadmium and tungsten may originate from independent processes at the same location. A next step in the source identification procedure was the calculation of an estimate of the contributions of the individual factors or aerosol components to the element concentrations in each of the lichen samples. Geographical maps of these individual contributions to the concentra- tions of a certain element give direct insight into the position of the associated sources and into the contributions of each of the sources to the total concentration of an element at a specific place. Fig. 4 shows a map of the unprocessed cadmium concentrations and maps of the separate parts of the cadmium concentrations originating from the cadmium-containing factors 4 and 5. Part of the sources of factor 4, and the source of factor 5 can be identified with industrial activities indicated in fig. 3. The largest source of cadmium in factor 4 can not be correlated directly with an industrial process actually going on, but it may originate from secondary emissions from dumps of zinc ashes. Fig. 5 shows a similar series of maps for antimony. An appreciable part of the antimony originates from soil contribution. The major source of antimony is associated with factor 3, comprising the volatile elements. The source of the corresponding component is possibly positioned just at the border of the area studied, but may be as well at greater distance in westerly direction. In the map of antimony from component 4 appears the same, yet not well identified, source as found for cadmium. The results presented illustrate how multi-element information and use of appropiate data interpretation techniques can'play an essential role in identifying sources of atmospheric pollutants. They underline the importance of multi trace-element analysis techniques such as INAA for environmental research and control. Future position of INAA in environmental science. It is always difficult to predict future developments in science and technology and one has to be very reserved when discussing the prospects of a specific technique. But there are no signs of developments in physics or chemistry, leading within the next decade to new routinely applied analytical technique for trace elements. Therefore, it may be worthwhile to discuss the future prospects of INAA, starting from the presently available alternative analytical techniques. When regarding INAA as a routine method for the simultaneous determination of many trace elements present at often low concentration levels, the only realistic alternatives are inductively coupled plasma emission spectoscopy (ICPES), X-ray fluorescense analysis (XRF) and charged particle induced X-ray emission spectroscopy (PIXE). Atomic absorption spectroscopy can not be regarded as a multi-element analysis method, whereas analytical techniques based on inorganic mass spectroscopy are not suitable for application on a routine scale. 105 CD - CflDHIUM BINs l.DD • < 5.00 • 2 5.00 • i ID.00 • > 15.00 • t 20.00 UHKHOUK CONC. HHXi 32.72 PPM CD-CONCENTR. IN LECRNORR CON 12. I!!!!!!!::!::::::!::::: IN -DE KEMPEN- CO IN FRCTOH V HINi O.OD • < 2.50 • t 2.50 :iyi!jijjpii. lillL :::::::::!:.. • * S.OO iniiiii ::::::5HBp:.I::::.::::::::::::::::::. ••::::: ::::*::KnR::::::::: •::::::::::::::::::. ••::::. • » 7.S0 • t 10.00 UNKNOHN CDNC. HRXi 31.01 «.•». .. PPM CONCENTR. IN iiii^::ii:ii::i;ii::::::::;:: iiiiiijiiiiiiiiii:"' LECflNORR CONIZ. IN -DE KEMPEN- I:::?::::::::;::: mi CD IN FACTOR 5 MNt D.DO •*< 2.50 ••:•••••!••••!••• ••••::•••••• !i!!!!IiSi!S!i!- ii Iliii, • t Z.BD > » S.OO • t 7.50 ••*••••••••••••• :s • I 10.00 iiH::::iiijiiiffiilkB!!ih»..' ""iniim:..»in!iU UNKNOHN CONC :u::::::::;;::::;::;:::::::r -:;:::::::::::;::: PPM ii|iii!!i!!S!i!SJ!i!!!h!!!!!!!!!S!!!J!!!i!jjj!!J! CONCENrR. IN :i::::::::: l^it!«Jii|ii;:::!:::i:i::::i:::i:i::i:i::i::i:;'• IN -DE KEHPEN" ;::.;;::;::;.;:; ;:::;:::.:::::.. 1RI i #v"^^ r^Ni;iL ' .... Fig. 4. Geographical distributions of total cadmium (a), and cadmium from factor 4 (b) and factor 5 (c). 106 SB - UNI I MOON -RNTIMONT HINi 3.37 • < 10.00 • 2 10.00 • > ao.oo • » 3D. 00 • 2 HO.00 UNKNOHN CONC. HflX: 61.2B PPM SB-CONCENTR. IN LECRNORR CQNIZ. IN "DE KEHPEN- SB IN FRCTDR 1 HINi 0.00 • « 5.00 • t 5.DO • > ID.00 • > 19.00 • 2 20.00 UNHNOHN CONC. tmx: 2U.U6 PPH CONCENTR. IN LECfiNOHR C0N1Z. IN -DE KEHPEN" liti SB IN FHCTDH 3 ::::::::::::::::: ::::::: HINi 0.00 ;::::::::::::::: i::::::iii::i:::::ii:i::i :::::::ir::::::::::::::' ::;;;:::::: • < 5.00 • « 5.DO iiiii ::::;:::::: • > 10.00 • <• IS.00 iipijjjiiHiiiji| ======• t 20.00 i:::::: UNKNOWN CONC. •IP |M»»:::: hnxi 27.aa Illllllll::"" iiiii :::::|c::::::::::::::.:::::::::: ...::::::::::::::::::::::: PPM CIIII CDNCENTB. IN LECBNORB CONIZ. UBisiiiiihRliiiiiiiilll !!Hffi!!ii!i!!!!iii!l!!iiii;;iii!iii!niii!l!i;!i;!r IN "DE KEHPEN" ::::::::::::::::::::::::•i ^^x^iiiiiiiiiiiiiiiiMiiiiiiiiiiii mi KHHP""" •S«!Si* HlBliJH;IHIilllllillllU SG IN FRCTDH HlNs 0.00 • « 5.00 • « G.00 • > ID.00 • » IS.00 • * 3D.00 UNKNOHN CONC. Hill: 20. 12 PPM CONCENTR. IN LECPNORfl C0N17. IN "OE HEMPEN^ Fig. 5. Geographical distributions of total antimony (a) and antimony from factor 1 (b). factor 3 (c) and factor 4 (d) 107 Of ICPES the sensitivity seems on the average comparable to what can be obtained by INAA; for water, ICPES seems even superior when no preconcentration is applied (35). For solid samples, the accuracy of ICPES may be affected by contamination or losses in the dissolution step. For most elements, the detection limits obtainable by energy dispersive as well as wavelength dispersive XRF are higher than those for INAA or ICPES (36). For PIXE, the minimum detectable masses are comparable to, and for some elements even lower than those for INAA (37). But since PIXE can only be applied to. very thin specimens, it provides an alternative to INAA only for a limited number of sample types, such as air filters, thin slices of biological materials or trace elements in water after preconcentration. Moreover, application of PIXE is expensive because of the extensive use of a particle accelerator. In the author's opinion three fields of application can be indicated where INAA is at present, and will be in the foreseeable future, the method of choice for multi-element trace analysis - for routine analysis of materials which are difficult to convert into a solution suitable for ICPES; - in cases where only milligram quantities of sample material are available; - as reference method for certifying standard materials or for testing other analytical techniques. A further increase of the supply of environmental samples for INAA can be expected as a result of increasing use of trace element pattern interpretation procedures in environmental research and monitoring. REFERENCES IM G.L. Schroeder, H.W. Kraner, R.D. Evans, T. Brydges, Saienee J_5£ (1966) 815-817. Ill D.E. Robertson, R. Carpenter, Neutron Activation Techniques for the Measurement of Trace Metals in Environmental Samples. 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Publ. in Nual.In8tr.Meth. 142 (1977) 1-338. 108 RNAA DETERMINATION DF As.Cd AND Zn IN BIOLOGICAL MATERIALS E.Taskaev, Iv.Penev and L.Kinova Institute of Nuclear Research & Nuclear Energy, boul.Lenin 72, Sofia-1184 In conection uith the monitoring project No 3739/RB promoted by the International Atomic Energy Agency, Vienna, uas necessary to determine Hg,As, Cd,Cu and Zn in some human organs. As the rational approach, on our opinion, is to determine these elements in a single spesimen, us have choosen the consecutive extraction* Aiming at getting reliable results ue used uell established systems: ditizone uas used to separate Hg and Cu (1), and As, Cd and Zn uere extracted as diethyldithiocarbamate complexes (2-5). Special attention uas payed to the accuracy and precision of the determination^) . Monitoring, optimization of cooling time and control of chemical yield uere carried out in each case. EXPERIMENTAL Preparation of samples for irradiation. Liophilized and homogenized human organ samples uere ueighted and packed in polythene capsules. Samples' weights were up to 5Q0mg. The preparation of samples for the analysis met almost all the requirements of the IAEA.SRM Bovine LivBr 1577a (NBS), Bouen's Kale and chemical solutions uere used as comparative standards. Irradiation. The samples uere irradiated in the vertical channel of the IRT-2000 reactor in Sofia, in the termal neutron flux of about 5.1012 n.cm—?s~! for 24 h. Each sample uas monitored uith iron monitor. Cooling time varied from 20h to 30h. „ 6Q Counting. V'-Spectrometer uith 56 cm GeLi (2.5 kev resolution at Co) and multichannel analyser CANBERRA-40 uas used. Counting time uas up to In. Cadmium fractions uere left after separation for 24h to reach equilibrium 115-Cd - 115-In. The standards and final extracts uere counted in 25ml volume flasks. The following isotopes uere used to calculate the contents: 197-Hg Ev <= 77 kev T1/2 = 64.1h 76-As Ev = 559 kev Ti/2 = 26.4h 115-Cd E« = 52B kev T1/2 = 53.4h (for control only) 115-In El = 336 kev Ti/2 = 4.5h 69-Zn E- = 439 kev T1/2 = 13.9h 65-Zn . Ev = 1115 kBv T1/2 = 244d (for control only) 64-Cu Ey = 511 kev T1/2 = 12.7h Chemical yield determination. 0,5ml aliquotes of the respective organic phases uere dried in polythene capsules at the room temperature and irradiated in the described conditions for 6h. Ue used 115-Cd, 76-As and 69-Zn for the chemical yield determination. Chemical separation. Carriers uere added to the speciment before dis- solution: 2mg of Hg and Img of As,Cd,Cu and Zn* Acid mixture of cone. H2SO4, 10% HCIO4 and 1U0>» HNO3 (1:2:5) uas used to dissolve the speciment. Dissolution uas carried out in slightly modified Bethge apparatus. After 30min boiling ( 110°C) the nitric acid uas distilled (end of distillation at 205°C) and collected. The left uas transfered in an extractor, the flask uas rinsed uith distilled uater, rinsings added and the acidity adjusted up to 4M H2SO4. Mercury and copper uere extracted uith tuo 10ml portions of ditizone in CHCI3. The solution uas transfered to thebeaker and to achieve the acidity of 3M HC1 about 2.5ml of cone. HC1 uere added. Uith a pinch of KI As(U) uas reduced to As(lll) while boiling. Then the solution uas cooled and return back to the extractor. About 200mg NaODC uere added and arse- nic diethyldithiocarbamate uas extracted uith tuo 10ml portions of CHCI3. The extracts uere gathered, uashed uith 2M HC1 and counted. Adding 1M NaOH the pH of the solution uas adjusted CIOSB to 11, and about 300 mg NaDDC uBre added. Both zinc and cadmium DDC complexes uere extracted uith tun portions (10ml) of chlororm. The extracts uere gathered uashed and counted. RESULTS AND DISCUSSION The described procedure alloued us to determine As, Cd and Zn content in a single specimen uith high accuracy. Mercury determination uas not sufficiently selective and did not meet our requirements for several reasons. Since 197-Hg uas choosen as analytical isotope, the counting conditions depended on thB amount of 64-Cu in ditizone fraction. It uas even impossible to find any mercury in the samples uith comparatively high copper content (e.g. Bovine Liver 1577a). 109 Moreover ue pinned to use 203-Hg (279 kev) as a tracer for chemical yield determination. Insignificant, but desturbing coextraction of75-Se uas established too. The above mentioned reasons directed us to additional separation step, uhich gave good results. MBrcury uas reextracted from the ditizone fraction uith 4I"I KBr in 11*1 H2SO4. pH of the solution uas adjusted to 6 and Hg uas extracted again uith chloroform solution of ditizDne. Ue deliberately reconciled to some mercury losses during HNO3 distillation, simplifying the procedure. They uere about 1 2/i according to our estimation. Further on ue intended to replace the polythene ampules u/ith the quartz ones and different uay of monitoring uill be introduced (7). That uill allou us to eliminate some of the possible errors and to obtain better results for Hg. Despite of the identically applied procedure the chemical yields obtained uere defferent each time. That confirmed our confidence to control it every time. Some preliminary experiments uere made on chemical yield determination of arsenic uith 77-As (239 kev) tracer. The latter one prooved to be more precise and less time consuming. Ue had good agreement betueen yield values obtained by reirradiation and tracer. Using the described procedure ue determined the As, Cd and Zn content in human spleen,kidney,heart and liver samples and in SRn Bovine Liver 1577a and Bouen1 s Kale. The results for the 5RFI are given in Tablei. Table 1. As. Cd and Zn content in Bovine Liuer 1577a and Bouen1s Kale 1 Content} Bovine Liver 1577a (NBS) I Bouen sTKale T ppb I x±2.S0 ILD I LQ I Ref.(B) I x*2.SD ILD 1 LU 1 Ref.(8) As 45.9*3 .6 0 .15 0 .50 47*6 11.0*10 0 .33 1. 1 140*20 Cd 496*88 22 75 440*62 960*140 34 11 3 690*90 Zn ppm 120*8 0 .7 2 .3 123*-8 30.0*2.B 0 .7 2. 3 31.0*2 .2 L0 - limit of detection, LQ - limit of quantitation ACKNOWLEDGMENT The authors are grefetful to the International Atomic Energy Agency, Vienna, for financial support. REFERENCE 1. Gladyshev U.P., et all, Anal. Chem. of Mercury, Nauka(i974) (loscou, pp 52-55 (in russion) 2. Uyttenbach A., S.Bajo, Mnal.Chem., V47,No11 (1975)1813-17 3. Zgivopistsev U.P., E.A.Selezneva, Analytical Chemistry of Zinc, Nauka (1975) Moscou, p.46 (in russion) 4. Bajo S., A.Uyttenbach, Anal.Chiam., V49,No1 (1977) 158-61 5. Bajo S., A.Uyttenbach, Anal.Chem,. V51,No3 (1979) 376-7B 6. Quality assurance in biomedical neutro activation analysis, IAEA-TECDOC- 323, Vienna, 1984 7. Geisler M., H.Schelhorn, Isotopenpraxis, 18 (1982) 54 8. Parr R.M., IAEA/RL/103, 1983, Vienna 110 DEFINING OF CONCENTRATION FACTORS IN THE BIOTA OF THE RIVER SAVA BY THE METHOD OF NONDESTRUCTIVE NEUTRON ACTIVATION ANALYSIS S. Lulic The Rudjer Boskovic Institute Center for Marine Research Zagreb Bijenicka 54, 41000 Zagreb, Yugoslavia INTRODUCTION The effects of nuclear power plants (NPP) upon the pollution of the environ- ment are becoming more and more a great problem both for the countries where the NPPs are constructed and for those where their radioactive effluents could appear in rivers, sea or the atmosphere. The present experience in the field of radioecology has clearly proved that the level of radioactivity is not the only deciding factor in an ecosystem, there is also the uptake of radioactive substances into organisms, depending upon the phys- ico-chemical state in which particular radionuclides are found. Therefore, the chemical contents of inactive parts of effluents and possible interactions of dis- charged radioactive effluents in the environment are of a special radiological in- terest . Having this in mind it is very important that before a NPP has been constructed a thorough investigation is carried out with respect to each particular system of a NPP and location and fate of effluents discharged into the environment. The radioactive material is the product of the nuclei decay, capture of neutrons, or the decay of radioactive isotopes. In the cooling water of a reactor, besides cor- rosive products we find also the products of nuclei decay. The greatest problem of the environmental pollution in the case of the Krsko Nuclear Power Plant presents the discharge of radioactive effluents into the river Sava. Even though the discharging of radioactive substances into the Sava causes their temporary dilution, certain plants and animals accumulate them during phys- iological processes. Accumulation of particular radionuclides on the basis of the physico-chemical processes with sediments and suspended matter of the river Sava has been examined. We should emphasize that various industries discharge their ef- fluents into the river Sava (acids, surface active substances, coal particles and various organic and anorganic substances) which essentially influence adsorption- -desorption processes of particular radionuclides. Therefore, in order to define the capacity of particular biological species or to define bloindicators of radioactive pollution it is necessary to know the values of concentration factors. Values of a concentration factor may be defined on one side from the ratio contents of radionuclides in a particular biological species and the water, and, on the other side, from the ratio contents of a par- ticular element in a biological species and the water. To define concentration factor values we have been using the latter method, namely we have been defining the contents of elements by the method of nondestruc- tive activation analysis because the level of radioactivity in biological species, sediment and water was too low to enable us to establish the ratio of their con- centration factor values for a sufficiently large number of radionuclides. EXPERIMENTAL The samples of biota were first dried at room temperature, then at 110°C, homogenized and finally stored into plastic ampules. A 2 liter water sample was evaporated to dryness, homogenized and stored into a plastic ampule. In this way the prepared samples of biota and the water, together with a standard (prepared in the same way as the NBS standard Reference Material 1577, Bovine Liver) were sent to be irradiated in the TRIGA reactor of the Jozef Stefan Institute in Ljubljana. The samples and the standard were irradiated under the same condition, i.e. under the flux thermal neutrons 1.8x 1012 neutron/cm2/sec during 48 hours, namely in integral neutron flux 3.1 x101? neutron/cm2. After irradiation, the sample and the standard were .ft to get cooled for a certain period of time and then counted by a "Canberi-a" 4096 multichannal analyser and a 40 cm3 Ge(Li) semiconductor detector with 25% of efficiency and about 2 keV resolution. From the gamma spectrum obtained the number of elements was calculated by the absolute method of neutron activation analysis using the following equation: A x M 6.023 x 1023 xtf x£x S x 6 where, g - the weight in grams A - the activity measurement 111 M - the molecular weight of the target material (5 - the activation cross section fD - the neutron flux \. S - the saturation factor, S = (1 - e~' ), where, X - the radioactive constant t - the time irradiation Q - the isotopic abundance RESULTS AND CONCLUSION In ten samples of biota, benthos, sediment, seston and the water, concentra- tions of 14 elements have been defined by the method of nondestructive activation analysis (Table, the first line). On the basis of the calculated concentrations of particular elements in biota, benthos, sediment, seston and the river Sava water, concentration factors have been calculated for particular elements (Table, the second line). The concentration factor, _p _ Concentration of element in aquatic organism (g/g wet weight) Concentration of element in water (g/ml water) The values of concentration factors range from 10 -10 . The concentration factors have been used to define accumulations of particular radionuclides or elements in aquatic organisms. On the basis of experimentally defined concentration factors organisms serv- ing as bioindicators for the control of radioactive contamination of the river Sava caused by the work of the Krsko Nuclear Power Plant have been determined. 112 Table 1. Concentrations and concentration factors in Sava river sar.ple-5 nement E(keV) S a m p 1 e Side Water Chladophera Sediment Gancarus Hirudinea Alburnus Rutilas 46 So So 889 5.68(12? 1.42(6)** 5.50(6) 7.28(7) 7-95(10) 2.50(5)*** 9.68(5) 1.28(5) 1.39(2) Cr 51Cr 320 7.90(10) 1.91(5) 6.24(5) 2.91(6) 2.41(4) 7.89(4) 3.68(3) Fe 59Fe 1098 5.56(8) 1.26(2) 3.45(2) 2.56(3) 6.03(5) 1.23(5) 7-91(6) 2.26(5) 6.20(5) 4.60(4) 1.13(3) 2.21(2) 1.42(2) 60 CO Co 1332 5.13(11) 2.17(6) 4.57(6) 3.98(7) 6.85(8) 4.65(9) 6.51(9) 4.23(4) 8.91(4) 7.76(3) 1.33(3) 9.06(1) 1.27(2) 65 Zn Zn 1115 3.07(8) 1-85(4) 6.18(4) 3.60(5) 1.49(5) 3.06(5) 2.71(5) 6.02(3) 2.01(4) 1.17(3) 4.85(3) 9.97(2) 8.83(2) ft. 75 Se 'Se 401 5-98(9) 6.19(6) 8.60(5) 2.29(6) 2.58(7) 4.08(7) 1.03(3) 1.44(4) 3.83(2) 4.31(1) 6.82(1) Sr 85Sr 514 2.19(7) 1.50(4) 6.84(2) 86 Rb Rb 1076 1.20(9) 1.67(5) 5.18(5) 4.79(6) 2.17(6) 2.38(6) 1.39(4) 4.32(4) 3.99(3) 1.81(3) 1.98(3) 6.7K4) 110m Ag 'Ag 658 7.38(11) 3-17(8) 8.3K9) 8.55(9) 4.29(2) 1.13(2) 1.16(2) 121 Sb Sb 1695 4.97(10) 1.15(6) 3.17(6) 2.58(7) 5.34(8) 6.61(8) 2.31(3) 3.63(3) 5.19(2) 1.07(2) 1.24(2) Ba 131Ba 496 5.43(9) 2.07(4) 7.39(4) 5.54(5) 6.09(6) 1.11(6) 3.81(4) 1.36(5) 1.02(4) 1.12(3) 2.04(2) Cs 131Cs 796 6.22(11) 1.49(6) 6.04(6) 9.26(7) 1.46(8) 1.24(8) 2.39(4) 9.71(4) 1.49(4) 2.35(2) 1.99(2) 140 La La 1595 9-35(10) 3.18(6) 3.23(6) 8.73(7) 3.40(3) 3.45(3) 8.95(2) 152 Eu Eu 1407 1.02(12) 1.36(7) 4.02(7) 7.54(10) 1.33(5) 3.94(5) 7.39(2) concentration in g/ml water 5.68(12) = 5.68 x 10-12 fit concentration in g/g wet weight 1.42(6) = 1.42 x 10-6 XXX value of the concentration factor 2.50(5) = 2.50 x 105 AHALTSIS OF 80MB MDOfiAL SILTS BY EEVTRW ACTIVATION MTROD Ana Pantelloa, Maria S&lagean, Stefania Splrldon Institute for Physios and Nuolear Engineering Buoharest 11G-6, Bomania Ob, Spiridon Inatltuts for Biology and Animal Nutrition Bucharest, Romania IHTBODUOTIQN The industrial system in animal and poultry bringing-up has determined many ohangas in tha technology of exploitation aspeoially in the nutrition and tha technology of feeding problems. In the mineral nutrition domain many studies of the specialists have been issued in order to provide the animal feeding with some mineral compounds and various essential trace minerals together with their tozioity limits* Obviously in these conditions the composition of these minerals must be very well known. On this purpose the neutron activation analysis has been used. Three oaloium carbonate samples from different mining sites all1 over the country have been analysed. She samples were homogenised and dried, Two irra- diations have been oarried outi - One of 4 hours for the samples ( Or 20 + 2 8 ± 1 2.3 + 0.4 Os < 0.2 0,7 t °»l 1.8 j 0.1 Dy 2.3 ± °«* 2.1 + 0.4 - 114 0.28 + 0«05 0.47 + 0.07 0.04 + 0.01 0.35 + 0,01 0.42 + 0.02 0.062 • 0,005 Ef 0.30 + 0.08 0.7 t 0,1 0.17 + 0.05 < 0.08 0.24 + 0.08 0.04 + 0.03 La 5.9 + 0.4 10.0 + 0.6 1.14 + 0,09 Lu(ppb) 40 • 7 75 t 11 27 ± 5 1.5* • 0.16 0.30 t 0.10 0.72 t °'08 MB 214 + 13 292 + 16 307 ± 18 Ho 9 1 4 • 1 £ 4 + 1 Ma(J6) 0.26 0.02 0.062 0.005 * t 0.036 + 0.003 Hb • c 18 + 6 < > 6.4 + 3.5 Sb 0.21 • 0.04 0.62 £ 0.09 + 0.02 + 0.09 So 0.65 0,05 0.74 t 0.05 0.17 + 0.01 8M 1.22 • 0.07 1.7 + 0.1 0.31 02 Sr 281 ± 32 354 + 36 179 t °' Tb 0.13 + 0.07 0.3 + 0.1 * 19 fa 6 ± 2 4 + 1 Sh 1.2 • 0.1 1.3 ± 0.1 0.19 + 0.04 Ti 385 i 123 511 + 107 475 + 175 U 2.2 t 0.3 0.9 + 0.1 1.1 ± 0.1 ? 26 + 3 26 + 2 4 + 2 Tb 0.5 0.1 0.6 • 0.1 0.15 + 0.04 Zft 20 ± 3 21 £ 3 5 + 1 Ft, 115 DETERMINATION OF TRACE ELEMENT CONCENTRATION FACTORS IN SOME MARINE ORGANISMS BY NEUTRON ACTIVATION ANALYSIS A. Vertacnik,S.Lulic Center for Marine Research Zagreb, "Rudjer Boskovic" Institute, Zagreb, Bijenicka cesta 54, Yugoslavia INTRODUCTION The organisms living in sea water media are effective accumulators of chemical elements, among which a number of essential or nonessential trace elements. In order to determine the concentration of some trace elements, their concentration factors and possible pathways through the food chain, neutron activation analysis of various marine organisms was performed. EXPERIMENTAL Selected marine organisms (Table 1), sampled from the middle Adriatic area were dried at 11O°C, grinded and 0.2000 g of each weighed into polyethylene ampoules, as well as the sea water residue after rotavapor evaporation. Samples together with 0.200 g of NBS SattpU numberOrganismsSoil-5 standard were irradiated under neutroSoil-5n standarflu xo fUd 8 werx e irradiate n/cn)2sd fo under r 1. Fucus virsoides J.Ag-Phaeophyta ™™ 2. Posidonia oceanica (L.) Del. k8 hours in "™&n reactor- "J- Ste" 3. Zooplancton fan" Institut^ A nondestructive NAA 4. Area noae L.-Molusca was Perf°™ed by u^ing gamma-counting 5. Spirographis spallanzani Viviani-Polyheata s^stwi which oonsisted of the 40 cm3 6. Eriphia apiniformis(Herbst)-Crustacea Ge(LL) crystal (FWHM 2"10 for 1332 7. Labrus merula-Labridae keV' Peak: CmPtm 29:1- eff- 7'2%) 8. Maena chryselis Cuv.et Val.-Maenidae attachec to a ^096-channel pulse- 9. Conger conger L.-Muraenidae "heieht analyser. The quantities of trace elements (expressed in g/g wet T bl - organism) were calculated from charac- teristic photopeaks after all necces- sary corrections for efficiency, geo- metry, decay sheme had been applied, and listed in Table 2. RESULTS AND DISCUSSION Concentration factor, defined as the ratio of the element concentration in an aquatic organism to that in the surrounding water under equilibrium or steady state conditions can be calculated from the formula: CF _ ^l^wet org. gel/mlsea water CF values listed in Table 2 are meant to represent edible portions, so the> are weighed toward muscle and soft parts of the organism. Lower organisms such as brown algae and marine plants are excellent accumulators of Sc, Fe, Co, Br, Rb, Sr, Sb, Cs, Ce and Cr, Zr, Eu, Au, Th (from cone, per wet weight) which they concentrate from the ground they are growing on. Inver- tebrates, as shells or crabs are good accumulators of Zn, Se, Br and Ag, while fishes are poor accumulators of microelements except Zn, Se, Sr and Cs. 1 ii Cur- experimentally obtained CF values are in the range 10 10 , that is in good agreement with the literature data (1,2,3). Some difference in CF's for Sc, Fe, Sb, Cs and Ce may be the result of different microelement availability for marine species that had been investigated on the limited middle Adriatic area. 116 Table 2. Microelement concentrations and CF values for some marine organisms. Element SAMPLE Radionuclide Sea 1 2 3 4 5 6 E (keV) water 7 8 9 Sc 5.33(11)* l.B6(Bf* 1.17(7) 8,15(8) 1,46(8) 5.30(8) 3.25(9) 4.B4(9) 1.48(8) 7.85(10) 46 Sc-BB9 3.36(2?*•"2.01(3) 1.44(3) 2.64(2) 9.58(2) 5.90(1) B.EO(l) 2.68(2) 1.40(1) CT n.d. 7.08(7) 1.70(6) 9.03(7) 2.59(7) 5.75(7) 1.21(7) 1-47(7) 4.05(7) 3.85(7) 51Cr-320 ------Fe 2.58(7) 3.62(5) 1.31(4) 3.77(4) 4.11(5) 1.62(4) 2.0B(b) 3.31(5) 6.87(5) 9.00(6) 59Fe-109B 1.40(2) 5.08(2) 1.46(3) 1.59(2) 6.28(2) 8.10(1) 1.28(2) 2.66(2) 3.50(1) Co 2.94(10) 1.46(7) 2.99(7) 9.54(e) 2.09(7) 1.70(7) 3.30(8) 1.53(B) 3.91(8) 1.43(8) 60Co-1332 4.97(2) 1.02(3) 3.24(2) 7.11(2) 5.7B(2) 1.12(2) 5.20(1) 1.33(2) 4.90(1) Zn 1.66(B) 9.38(6) 9.95(6) 2.55(5) 2.43(5) 1.55(5) 2.82(5) 1.48(5) 2.18(5) 1.68(5) 65Zn-1115 5.62(2) 5.99(2) 1.54(3) 1.46(3) 9.34(2) 1.70(3) 8.92(2) 1.31(3) 1.01(3) Se 9.00(11) 2.94(8) 8.03(8) 2.09(7) 1.01(6) 8.42(7) 2.87(7) 3.51(7) 8.61(7) 4.3B(7) 75Se-401 3.23(2) B.92(2) 2.32(3) 1.12(4) 9.36(3) 3.19(3) 3.90(3) 9.57(3) 4.87(3) Br 6.85(5) 9.95(5) 1.72(4) 1.26(4) 2.74(4) 6.80(4) 1.93(4) 3.02(5) 1.95(5) 2.51(5) 82Br-1475 1.40(0) 2.50(0) 1.80(0) 4.00(0) 1.00(1) 2.80(0) 4.00(-l) 3.00(-l) 4.C0(-l) Rb 1.46(7) 2.36(6) 3.69(6) 9.11(7) 6.55(7) 1.20(6) 1.60(6) 8.73(7) 7.39(7) 5.84(7) B6Rb--1076 1.62(1) 2.53(1) 6.20(0) 4.50(0) 8.20(0) 1.10(1) 6.00(0) 5.10(0) 4.00(0) Sr 3.19(6) 1.13(4) 3.49(5) 1.29(4) 9.05(6) 1.52(5)" 5.23(4) 9.02(5) 5.46(5) 2.29(5) B5Sr-514 3.54(1) 1.09(1) 4.04(1) 2.80(0) 4.80(0) 1.64(2) 2.83(1) 1.71(1) 7.20(0) Zr n.d. 3.03(9) 1.14(9) n.d. 1.12(9) n.d. !.!4(9^ n.d. n.d. 95Zr-756.6 ------Ag 3.60(10) 1.26(7) 9.89(8) 2.28(8) 2.50(6) 2.33(6) 5.21(7) n.d.^ n.d. 3.B5(B) llOmAg-658 3.50(2) 2.75(2) 6.33(1) 6.94(3) 6.47(3) 1.45(3) - - 1.07(2) Sb 1.79(9) 4.92(8) 1.53(7) 1.07(7) 1.64(8) 2.90(8) n.d. 4.53(9) n.d. 8.42(9) 126Sb-1695 2.71(1) 8.55(1) 5.98(1) 9.20(0) 1.62(1) - 2.50(0) - 4.70(0) Cs 7.99(10) 4.60(8) 2.44(7) 1.92(7) 3.05(8) 1.21(7) 2.57(8) 7.2B(8) 7.39(8) 5.89(8) l3/lCs-795.7 5.B0(l) 3.05(2) 2.40(2) 3.80(1) 1.51(2) 3.20(1) 9.10(1) 9.20(1) 7.40(1) Ba n.d. 8.67(6) 7.33(6) 3.47(5) 2.04(6) 2.91(5) 5.88(6) n.d. 6.60(6) n.d. l31Ba-496 Ce 5.80(10) 8.95(8) 5.83(7) 2.45(7) 1.06(7) 1.44(7) 3.B7(8) n.d. n.d. n.d. ""ce-145.6 1.54(2) 1.00(3) 4.22(2) 1.83(2) 2.48(2) 6.67(1) - - - Eu n.d. 1.32(9) 6.50(9) 3.75(9) 1.67(9) 2.14(9) 1.13(9) 7.63(10) 1.05(9) n.d. 132Eu-1407 Au n.d. 1.61(9) 3.B6(9) 5.78(9) 3.81(9) 2.67(9) n.d. n.d. n.d. n.d. 199Au-411.7 Th n.d. 2.74(8) 1.69(7) 8.86(8) 2.71(8) 4.87(B) 6.36(9) 1.53(B) 1.31(8) n.d. 233Pa-31l.9 concentration in g/ml sea water 5.53(11) = 5.53 x 10-11 K* concentration in g/g wet weight 1.86(B) = 1.B6 x 10 *** concentration factor value 3.36(2) = 336 n.d. = not detected 117 Experimentally determined CF values can be used for the calculations of marine food chains, as well as for the selection of indicator organism in the case of pollution by heavy metals or radionuclides. REFERENCES . (1) S.E.Thompson,C.A.Burton,D.J.Quinn(Y.C.Ng, Concentration factors of chemical elements in edible aquatic organisms, UCRL-50564 Rev.1, 1972. (2) G.N.Saenko,M.D.Koryakova,V.F.Makieriko,I.G.Dobrosmyslova, Marine Biology 34 (1976), 169. (3) D.Huljev.P.Strohal, Marine Biology 73 (1983) 239. i>ff 8 118 THE CONCENTRATION OF ACTIVE AND INACTIVE STRONTIUM IN SOME DANUBE RIVER SAMPLES K. Kosutic, S. Lulic The Rudjer Boskovic Institute Center for Marine Research Zagreb Bljenicka'54, 41000 Zagreb, Yugoslavia INTRODUCTION The present knowledge in radioecology has clearly proved that the level of radioactivity is not only deciding factor in an ecosystem. The physico-chemical state in which particular radionuclides are found is important for the uptake of radioactive substances into organisms. Among the radionuclides arising in uranium fission process, from the nuclear power plants, " Sr and Sr are of a particular importance for man because of their radiotoxicity. Strontium, being a chemical element with similar properties to those of the calcium, is metabolised by the food chains identically with calcium. Therefore, the presence of inactive and active strontium in the effluents and their possible interactions in environment are of a special radiological interest. This paper deals with some results of strontium concentration as well as con- centration factors for inactive and active strontium for some fish species in Danube river. The samples are colected during 1981. EXPERIMENTAL Inactive strontium in the water residue (after evaporation), sediment and fishes is determined by nondestructive neutron activation analysis by using the ^-counting system wnicn consisted of the 40 cm3 Ge(Li) semiconductor crystal (FWHM 2 2,1-1332 keV, peak: Compton = 29 : 1, eff. 7,2%) attached to a 4096-channel pulsehight analyser. The quantities of strontium are calculated relatively, using standard so- lution which contained 5 x 10 g of strontium per 100 \ . Radioactive strontium is measured after several separation procedures (1,2). 90 90 SrCO3 in equilibrium with its daughter Y (3) is detected in the /^-low-level counting antieoincldent system with gas-flow detector. Background rate was about 1 cpm, and eff. for Sr was 20-24%. The activity of Sr is calculated from the ratio of Sr activity in the sample and 9 Sr activity in the standard (150,92 90 mBq Sr/ml solution). Corrections for the efficiency as well as for chemical yield were applied. RESULTS AND DISCUSSION The results of total.strontium, active strontium and concentration factors for some Danube fishes and Danube sediment are presented in Table 1. The concen- tration factors were calculated from the formula: _„ _ gram strontium/gram fresh fish Sr = gram strontium/ml water ' 90 Cp _ mBq ' Sr/gram fresh fish 90Sr mBq 90Sr/ml water TABLE 1. 90 total strontium spec, activity Sr mBq 90Sr/g f mBq 90Sr Specie g /ml w QO our lit.(4) our lit.(4) Sr mg Sr results values results values mBq Sr/ml w 1.5 (5) Barbus barbus 1.37 (5)* 0.21* 0.55 110 15.2 1.1 (5) 0.46 73 Acipenser 1.4 2.39 (5) (5) 0.26 0.39 128 137 10.9 ruthenus 1.3 (5) 0.47 Abramis 3.26 (5) 1.1 (5) 0.44 0.57 brama 1.3 (5) 0.39 173 233 13.5 Stizostedion 1.75 (5) 1.1 (5) 0.26 0.39 94 lucioperca 1.9 (5) 0.72 135 14.6 Silurus glanis 4.06 (5) - 0.59 - 217 312 14.5 Cyprinus carpio 6.27 (5) - 1.05 - 336 557 16.7 Sediment 1.63 (3)** - 13.58** - 8727 7185 8.3 Water 1.87 (7)*** 2.0 1.89 (3)*** 37 - - 10.1 x 1.37 (5) = 1.37 x 10" ; for fish results in g/g freshweight or mBq/g freshweight xx for sediment results in g/g dry or r.Bq/g dry xxx for water results in g/ml or mBq/ml 120 Our results confirm the literature data CJ,5) that sediment concentrations of the total strontium and the active 90Sr are several times greater than those in the water. This can be explained with the fact, that the adsorption of strontium depends on the physico-chemical state of the sediment (6). Therefore, sediments are suitable and very sensitive indicators (static indicators) of long-term radio- active waste discharges. Fishes, that are living in the aquatorium are dinamic indicators of pollution, and they are the last link in the food chain towards man. Comparing the results for the fishes, we observed that concentration factors for Silurus glanls and Cyprinus carpio are much higher than the other fish species. This fishes, which are living near bottom can be used as a selected indicator organism for the radioactive pollution of the environment. REFERENCES (1) J.H. Harley, Editor, HASL 300 (1976). (2) J.R.Noyce et al., Environmental Radioactivity Standards, River Sediment, NBS (1975). (3) B. Al-Deen, S. Lulic, K. Kosutic, XI Jugosl. Symp. of HDZZ (1981), p. 99. (11) J. Chiosila, E. Revin, U. Chirovici, IAEA-TECDOC-219, Vienna (1979), P- (5) W.A. Goldsmith, E.W. Bolch, Proc. ASCE-SA 9£ (1970) 1115. (6) Gh. Furnica et al., IAEA-TECDOC-219, Vienna (1979), P- *»5. 121 MINERAL COMPOSITION OF THE PLANT SPECIES OF THE HYPERICUM FAMILY L. Marichkova, 0. Kjostarova Institute of Nuclear Research and Nuclear Energy Bui. Lenin 72, 1184 Sofia, Bulgaria INTRODUCTION Lately more and more the attention is payed to the mineral composition of medi cinal plants, as it is established that they are biologically active components as well as the healing agents as alkaloides, glucosidesand others (3,4,6,7). Medicinal plants have usually been used for a long time for treating chronic diseases. Having in mind the importance of microelements for the human body, we set ourselves as an objeot to investigate the element composition of some species of the Hypericum fa- mily. AB popular medicine uses water extracts from the epigeous parts of the plants the analysis were carried out on the epigeous parts of the plants as well as on their 10/o water extracts. EXPERIMENTAL The investigated objects were taken from different regions in Bulgaria. Previ- ously air withered epigeous parts of the plants are later dried at 60°C until rea- ching a constant weight and homogenity. Macro- and microelement concentration determinations were made by use of non- destructive method of neutron activation analysis (1,2,5) which because of its high sensibilitsxand accuracy gives the possibility for determination of trace elements (10~ -10" g) • On the other hand the method allows to determine wide range of ele»- ments. The elements: Mn, Ni and Sr in the epigeous parts of the plants were detera mined by X-ray fluorescent analysis, using Rh-tube and LiP (200) crystal. X-ray intensites were detected by both scintilation and flow counters. RESULTS AND DISCUTION The standards for quantitative analysis were laboratory prepared as well as international plant standard (kale pouder Bowin) was used. The results are tabulated. In table 1 the investigated plant species are given. In fable 2 macroelement quantities of Na, E, Ca, Cu, Pe and Zn in the epigeous parts of the examined plants as well as their 10# water extracts are given. AB it is seen the water extracts contain microelement concentrations in an order lower than the epigeous parts of the plants. Exception is the iron, where the concentra- tion is two orders lower. In table 3 the microelement quantities in dry weight in the epigeous parts and in 10# water extracts of the investigated species are given. It can be noted that the elements: Ce, Se, Cd and Sb are not found in water extracts The elements such as Sm, Or, Br, Ce, Se, Rb, Co and La are in concentrations in an order lower than in the epigeous parts of the plants. CONCLUSIONS 1. Using the neutron activation analysis totally eighteen macro- and microele- ments in. the epigeous parts of the plants as well as their 10$ water extracts in ten species of the Hypericum family are determined. Using X-ray fluorescent analysis the elements: Mn, Ni and Sr in epigeouB partB of the plants are determined. 2. The quantities found out in the extracts are in order lower than that in the epigeous parts of the plants except iron where the concentration in the extracts is two order lower than that in epigeous. 3. The elements: Ce, Se, Cd and Sb are not found in 10$ water plant extracts. 4. Toxic elements such as As and Hg are not found in the epigeouB parts of the plants in the examined BpecieB. Table 1. Investigated plant species of the Hypericum family Number of Plant species name the nrobe 1 H. calycinum L. 2 H. Patulum Thunb. 3 H. patulum Henryi. 4 H. andrsoenum L. 5 H. ascyron L. 6 H. maculatum Grants var. maculatum 7 H. inmaculatum Crante 8 H. tetrapterum Fries 9 H. perforation L. 10 H. olympicum L. 11 H. cerastoideB (Spach.) N. Robson 122 TABLE 1. Macroelement content of the diy drug Pumaria family specieB in ppm Number E 1E1EHIS of the Object probe Na K Ca Cu Pe Zn 1 Herba 254,7 9830 12330 56,85 246,7 56,35 2 „ 235,8 1(520 10190 48,54 223,6 143,23 3 128.6 11290 9390 93,84 214,5 126,22 4 n 92,8 8380 11120 79,12 309,4 89,98 5 112,10 9560 12530 85,82 432,1 63,91 6 83,2 10250 12850 68,34 456,2 69.97 7 n 74,4 12320 8850 70.21 602,4 101,82 1 Radix 436,9 5110 4290 96,32 1325 384,9 2 483,2 6050 3820 64,86 1436 231,9 3 345,6 6270 3050 1(8,26 2874 232,1 4 198,3 4940 4010 93,19 3925 934,6 \ 146,6 5000 4130 108,29 4449 781,2 6 134,3 5270 4320 72,84 4678 811.4 7 116,3 6110 3270 89,99 7856 941,8 3,4.5,7 Soil 2867 3268 1175 32,6 3234 1001,2 1.2,6 3256 2654 1984 24,4 3659 1012,3 TABLE 2. Microelement content of the dry drug Fumaria family species in ppm Number E I E ME N I S of the Object probe Sm Or Sb Br Se Rt» Co La 1 Herba 1,6409 1, 0002 0,5123 4,2534 0,2209 29, 92 0,,6044 1,6432 2 M - 1.,9144 0,7214 3.6463 0,2405 23, 48 0,,1903 0,8458 3 n 0,7544 - 0,5804 6,25B1 0,3002 48. 12 1,,5062 0,9384 4 n - 0,,5273 0,6921 2,5497 0,2348 32,45 1.,6676 2,5384 5 H - 0,8891 0,4418 5,8673 0,2005 43,,18 o,,5539 3,0505 6 n 1,9253 0,8570 0,4623 5,1138 0,2926 44,,57 1.,7825 3,4817 7 II 0,3658 0,,5872 0,9223 6,2543 0,2887 52.19 1,,4008 2,9436 1 Radix 1,9405 1,•2568 0,3182 0,3856 0,2386 3,4561 o,,9325 2,3645 2 n 0,9886 2,,0824 0,5085 0,2934 0,3425 3,,2834 0,3856 1,0506 3 n 0,3245 0,8623 0,4666 1.1800 0,3964 4,,?257 2,,9637 1,0018 4 H 0,2218 0,,9628 0,4352 0,3565 0,2852 3,,2*79 2,8425 3,2456 5 n 2,3458 1,,2432 0,2856 0,4283 0,245B 4,,2^62 0,9994 3,9896 6 it 0,8563 1,,4587 0,2234 0,4811 0,1851 4,,3796 1 ,1815 4,0516 7 a 0,1215 0,,1613 0,6524 1,2384 0,2256 4,,9835 1,2365 3,0128 3,4,5,7 Soil 8,1986 1 ,2863 0,7362 18,74 0,4236 36,,12 2,8689 1,1180 1,2,6 n 7,1097 1 ,3287 0,4186 16,93 0,3811 43 ,18 3 ,1234 2,6822 The elements: manganese, strontivun and zirconitim are detrained by meanB of X- ray radio fluo re scent analysis and their concentrations in ppm are in the follow ranges Object Mn Sr Zr Herba 4,239-9,112 33,038-43,84 0,0611-0,1660 Radix 12,385-21,431 37,42 -85,27 n n Soil 400,00 -450,00 170,75 -175,0 106,7 -1 16,00 123 continuation of the Table 5-concentration of the elements, present only in the dry weight of the plants in ppm Number of the E L E M E N T S probe Ce Se Cd Sb Mn Ni Er 1 0,569 0,592 15,45 0,55 51,51 2 - 0,144 2, 765 0,680 15,8 0,27 40,06 5 — - — 0,711 23,55 0,45 56,00 4 — 0,153 — 0,557 - _ — 5 - 0,265 - 0,459 49,54 0,50 92,00 6 — 0,844 - - 75,25 0,44 77,00 7 — - - 0,559 74,03 0,31 76,00 6 - 0,079 — 0,585 24,25 0,50 48,00 9 — 0,202 2, 071 0,873 45,04 0,40 45,00 10 0,827 0,565 — 0,547 55,76 0,51 46,00 11 0,494 0,271 — 0,589 105,61 0,54 45,00 REFERENCES 1. I. DCHnW, L. MARIGHKOVA, Compt. Ren. Bulg. Acad. Sci., 2, 1974 2. L. MARI0HK07A, I. DONBV, D. PASK07, P. NINOVA, Pharmacia, 6, 1976 5. V. ERMAKOV? V. KOVALSKI, Biological importance of Se, Acad. of Eci., USSR, 1974 4. B. KASAVINA and others, Mn. Resursi na Organisraa, M., 54-38, 1975 5. I. LONEV, L. MARICHKOTA, L. YAHKOV, Compt. Rend. Bulg. Acad. of Sci., 59, 1975 6. P. ELIAS, Maso lecivy rostl., 2, 1976 7. Reports and studies IMGO (PAO) DNESSCO, 1976 124 TRACE ELEMENTS IN TUlUUSh TEA INSTKUhENTAL NEUTKON ACTIVATION ANALYSIS H.Demiralp Technical University of Istanbul, Institute for Nuclear Energy, Ayazaga Kampusu, foaalak, Iatanbul-'l'uritey INXKODUCTIWI The human- body continuously assimilates a variety of inorganic elements from food and the environment. Some of these elements(AstSb,*n. Co, etc.) are aiosely related to human health and disorder as their deficiency or excess induces physiological and metabolic changesU;. Xhese elements are- usually present in agricultural products because of the increasing industrialization and associated pollution of the biosphere, uptake from the soil, fertilizer, pesticide treatment, and other industrial and domestic operation. lea is one of the most popular stimulating beverages which is consumed by low and high income family groups in many countries. Instrumental neutron activation analysis is one of the preferred methods(S,3) because information on a large number of elements can be obtained simultaneously. five packets each of the seven commanly used brands of tea were obtained from the market. In order to determine the transfer of trace elements into the drinkable portion, about 2-3 g. of the tea leaves were boiled in hot water for 2 min. Alter filtration the used tea leaves were dried at 65°C in an oven and a portion, about 200 mg. was used for ana- lysis, samples and standards ( NBS-SHM 1571 ) were irradiated lu min. and 2 hrs. at pneumatic system and central thimble in the i'ttlU* hAttk -11 re- search reactor. After irradiation, the activities of samples and standards were measured with a coaxial lie dedector ( Ortec UEto-18200 model ) coupled to a spectroacopic amplifier ( Ortec model 472 >. A Canberra 90 model multi- channel analyser with an 8k memory was used for pulse height analysis. The system has a resolution (FWitt) of .3.0 keV. for the 1532.5 keV. gamma ray of Co with peak to Compton ratio of 43:1 and efficiency of IB relative to the 3" x 3" Nal(Tl) crystal. Cooling and counting timeB were arrenged according to the nuclear properties of radioisotopes ( 4,5,6 ). The samples and standards were counted for 5 min. to 3 hrs. for the. determination radionuclidea. The analyzer system was calibrated with standard sources prior to every set of counting. The activity of the sample and standard was compared and from the elemental concentration of the standard ( 7,6 ), the element content oi the sample was calculated. In this calculation, necessary corrections for decay and counting time were applied taking into account half-life of radio - nudidea. Samples of each brand were irradiated in two seperate sets for all the measurments. Results of this study are presented. UEFEHENCBS 1/ S.Ahmad, h.S.Chaudhary et al, J.Kadioanal. Chem., 78(1983)375 2/ d.'iVi'enner, h.H.Freedman, o.hadioanal. Chem.,37(1977) 529 3/ j-.A.Ojuereshi et al, J.Kadioanal. Chem..68(1982)208 4/C .hishra, li.N.Shaikh, o.Kadioanai. uhea.78(1983)385 5/ G.Erdtmann(Ed.) Neutron Activation Tablea, 1976, Verlag Cheaie 6/ L.Hdiokwere, J.Radioanal. Chem.,85(1984)325 7/ S.Amiel, Nondestructive Activation Analysis, 1981, Elsevter Science 8/ D.DeSoete, H.&ijbels, J.Hoste, Activation Analysis, 1982, John Wiley and Sons 125 INVESTIGATIONS OF SOME REGIONAL RIVER SYSTEMS BY INAA AND X - RAY FLUORESCENCE R.J. DraSkovic", A. Kukoc Boris Kidric Institute of Nuclear Sciences - Vinca POB 522, 11000 Beograd, Yugoslavia M. Pantelic" Pedagogical - Technical Faculty 32000 Cacak INTRODUCTION Following our investigations of river systems in Yugoslavia ( 1 - 5 ), we have investigated distribution of some elements in materials dissolved in water ( C - parameters ) and suspended materials ( Csm - parameters ) in the rivers Ibar and Zapadna Morava by INAA, and the Ibar, Zapadna Morava and its tributary Kamenica, by X - ray fluorescence. The aim of these investigations was to obtain the data on eventual conta- mination of these regional river systems, and on intensity of such processes. EXPERIMENTAL Water ( 2 litres samples ) and corresponding suspended maperials were analyzed. Suspended materials were separated by sendimentation and filtra - tion. The water samples were evaporated and their dry residue used for ana - lysis. I. INAA Water and suspended materials of rivers the Zapadna Morava and Ibar ( Locations: Zapa-na Morava - upsteam and downstream of Kru - §evac and Trstenik ; Ibar - Raska and Mataruska banja ) were analyzed. Qw = 0.00522 - 0.00955 9 J Qsm = 0.03901 - 0.06488 g Irradiation: in VKG - channels of RA - nuclear reactor - Vinca 17 2 0 = 2.5 x 10 n/m . s ; Tirr = 3 days Measurements: On the SEIN ( France ) 4096 channels analyzer with Ge(Li) - detector - Ortec ( Gift of IAEA ); comparaison method ; TPA - treatement; contents of elements ( Zn, Hg, Cr, Sb, Sc, Fe and Co ) are expressed in nKg / g of dry materials. Distribution coefficients were detrmind by the relation D = Csm/ Cw. II. X - RAY ANALYSIS Analyzed samples: suspended materials of locations: - Kamenica, tributary of Z. Morava: v. Prijevor - Z. Morava:mouth of Vrnjacka reka in Z.M.: downstream of Kru§evac and of mouth of Rasina in Z. Morava, and - Ibar: downstream of Ra§ka and Mataruska banja 241 9 Qsm = 0.15 g; Source: Am ( 3.7 x 10 Bq ; E = 59.5 keV ) Excited characteristic line K*( L^in Pb ) Measurements:On 2000 - Channels analyzer withS«(Li) - detector Resolution : 170 eV za K^.- X emission of Mn ( Registred activity - calculated for 1 g of irradiated materials was used for determination of the contamination factors ) 126 RESULTS AND DISCUSSION Calculated distribution coefficients ( D = C / C ) are presented in sm Table 1. ( C and C - parameters are obtained by INAA ). sm w ELEMENTS RANGE OF RANGE OF sm/w sm/w IBAR AND Z.MORAVA OTHER RIVER SYSTEMS IN YUGOSLAVIA ZINC 4.9 - 227 CHROMIUM 54.7 - 147 a. 1.96 - 4.33 b. 2.68 - 4.04 c. 1.33 d. 2.85 - 18.88 ANTIMONY 1.45 - 21.2 a. 1.24 - 2.85 b. 2.33 - 7.46 c. 1.36 d. 1.07 - 2.76 IRON 64.5 - 89.3 a. 0.96 - 1.23 b. 1.92 - 12.87 c. 8.09 d. 1.71 - 13.26 Scandium 49 - 131 a. 1.22 - 1.88 b. 6.08 - 10.23 c. 1.08 d. 1.84 - 42.74 COBALT 4.1 - 45.2 a. 1.14 - 2.19 d. 1.15 9.72 TABLE 1. DISTRIBUTION PARAMTERS ( Dsm/W ) OF THE IBAR AND Z.M6RAVA RIVER SYSTEMS IN COMPARAISON WITH THE CORRESPONDING PARAMTERS FOR OTHER RIVER SYSTEMS IN YUGOSLAVIA ( a. Tisa b. Sava c. V. Morava d Danube ) On the basis of activity values ( A ), obtained by X - ray analysis,ca - lculated per 1 g of samples, we have determined contamination factors for investigated river regional systems, in comparaison on the uncontaminated wa- ter system: r. Kamenica, tributary of Z. Morava, as well as on mutual real - tions. CODE: r. KAMENICA r. IBAR r. Zapadna Morava v. Prijevor (1) downsteram of Raska (2) mouth of Vrnjacka downstream of reka (4) Mataruska banja (3) downsteram of Krusevac (5) 127 downsteram of mouth of r. Rasina (6) These contamination and mutual relation factors are: /A Ba: A? ,1 = 3.05 Y: A4 / A2 = 1.52 Ca: A2 '/Al = 4.47 Rb: Ag / A2 = 5.48 Fe: A6 ',Al = 2.55 Cd: = 9.18 Zn: Ap '/Al = 9.14 Ce-A6 / A2 = 5.38 Pb: A3 ,A =12.40 Sr: A A = 2.19 ' l 3/ 6 = 2.64 CONCLUSION Our data, obtained by INAA and X - ray fluorescence, indicate the possibi- lities of utilization of these two analytical matehods for investigations and control of biogeochemical and contamination processes in small regional water systems.which are especially important for modern studies in life sciences. REFERENCES / 1 / Draskovic" R.J., Investigation of Geochemical Characteristics of Co- mponents of Some Natural Water systems by Non - Destructive Radio - activation Analysis, University of Beograd, Thesis (1978) / 2 / Radosavljevid R.: Geochemistry of Fe, Co and Co in the Danube River System Water - Sediment, Water - Suspended Materials and Water - Biocomponent, University of Beograd , Thesis ,(1975) / 3 / Anovski T., Application of Isotopic Techniques for Investigations of Contamination of Water Systems, University of Skopje.Thesis(1984) / 4 / Minfieva B., Application of Activation Analysis for Geochemical Investigations of AUar Ores Region, University of Beograd (1983) / 5 / Dralkovic" R.J., Pantelid M., StepiC R., Radosavljevid R.,Some Pos- sibilities of Application of Nuclear Analytical Methods in Enviro- nmental Protection, Proceeding on Symposium of Epidemilogical Pro- blems in Protection and Progress of Environment, Pula,Yugoslavia, (1981),p.805 128 NEUTRON ACTIVATION INVESTIGATION ON THE ACCUMULATION OF SOME ELEMENTS IN TARAXACUM OFFICINALE, RESULTING FROM ENVIRONMENTAL POLLUTION I.Kuleff, R.Djingova Faculty of Chemistry. University of Sofia, HH26-Sofia,Bulgaria The world wide distribution of anthropogenic toxic metals has stimulated in- vestigations on the development of reliable methods for pollution monitoring. Since the microelements composition of pla.its usually reflects the chemical and geoi&hemical features of soil and environment the attention of the investigators has been directed towards discovering appropriate biological monitors of air, water, and soil pollution. In this respect we have proposed Taraxacum officinale (dandelion) as a bio- logical monitor /1/. Taraxacum officinale is a widely distributed plant growing at various latitudes and altitudes, near industries, in cities and in the bio- logical preserves. INAA has been used to determine the content of As,Br,Cd,Co,Cr,Hg.Mn.Sb,Se, Zn, and AAS - to determine of Cu and Pb in leaf samples of Taraxacum officinale, which were collected from three different regions in Bulgaria. The first one is round a smelter (i), the second - in a living quarter in a big city (2) and the third - high up in Rila mountains and may be considered unaffected by direct urban or industrial pollution. Samples from the first region were collected at different distancesfrom the emitting source, along the direction of the highest wind friquency. The results from the analysis have shown that in the leaves of Taraxacum officinale growing near the smelter there is an increase in the content of As (14 times),Br(j times) , Cd( 9 times), Co( 3 times), Cr( 2 times) , Cu( 3 times), Hg( 6 times), Pb(7O times) ,Sb( 1.2 times) ,Se( 1i4 times) ,Zn( V6 times) in comparison to normal "zero" values (region 3)• When the behaviour of these elements in depen- dence on the distance from the emitter was investigated it proved that they follow logarithmic dependence from the type: Ci = a + b.lnx where: C,= concentration of the i-th element in the leaves of the dandelion; x = distance from the polluting emitter (km); a = concentration at x = 1 km; b = the slope. The coefficients of correlation being: r. =0.9i»; r_.=0.89; r_ =0.97; rpb=0.90; 1^=0.95; rSb=0.99. There is also a linear correlation between the contents of Sb/Zn, Ca/Pb, Cu/Sb, Pb/Cd, Zn/Pb in the leaves of the plant. Br and Mn contents although being elevated in the vicinity of the smelter show more complex behaviour than the other elements. The concentration of Br in the leaves of the dandelion have a maximal increase on the 5-th km from the smelter. That is characteristic for pollutants which are in water soluble forms /2/. Analogous pattern of the concentration changes of pollutants released in gaseous state is detected by investigation of precipitation samples /3/. In the case of Mnthe maximum in concentration is detected on the 3-th km from the smelter. This is in good agreement with the theoretical prediction that the maximum of the aerosol pollutants concentration should be expected at a distan- ce 1.0-14 times of the height of the stack /Z/. The results from the analysis of the leaves of Taraxacum officinale, gro- wing in the living quarter of the city have shown that the dandelion can indi- cate also the urban pollution. For the concentration of As is 6 times higher in comparison to normal "zero" value (region (3) » of Br (2 times), of Hg (3 times), of Se (9 times), of Pb (j times). At the same time the concentration of the mentioned pollutants in the city is lower than that near the smelter. The results from the investigation have shown that the leaves of Taraxacum ofiicinale accumulate metals and thus reflect the level of environmental pollution. So it seems that the dandelion (Taraxacum officinale) will be very suitable bioindicator for local environmental pollution. REFERENCES /I/ I. Kuleff, R.Djingova, Water,Air, and Soil Pollut.,21 ( 1i98^) 77. /2/ V.Dobro- volsky, Geography of Microelements.Global Dispersion.,"Mysl" Publ.Moscow H98"}. /3/ J.Hallet.P.Lardinois.C.Ronneau, J.Cara, Pel. Total Environ.,25 (11982) 99. 129 DETERMINATION OF SOME ELEMENTS IN BOTTOM SEDIMENTS FROM VARNA BAY, BULGARIA, AND SARONIKOS GULF, GREECE D. Apostolov, M. Iovtchev, L. Kinova, F. Nikolov, I. Penev, S. Taskaev, T. Grigorov ' , A, Stojanov ^' and A. P. Grimanis, G. Kanias. C. Papadopoulou, M. Vassilaki- Grimani, D. Zafiropoulos * ' (1) Activation Analysis Group, Institute of Nuclear Research and Nuclear Energy, Sofia, Bulgaria (2) Radioanalytical Laboratory, Nuclear Research Center "Demokritos", Athens, Greece (3) Institute of Marine Research and Oceanology, Varna, Bulgaria INTRODUCTION Within the framework of the project "Uethodology and application of neu- tron activation analysis in ecology" between the Activation Analysis Group, Institute of Nuclear Research and Nuclear Energy, Sofia, and the Radioanaly- tical Laboratory, Nuclear Research Center "Demokritos", Athens, was determi- ned the content of toxic and other trace elements in seawater organisms and bottom sediments from Varna Bay and Saronikos Gulf. The investigated regions are characterized with highly concentrated po- pulation and various industrial activities. The purpose of the project is discussed in other work , as well as the results of the determination of ni- ne trace elements in fish Gobius niger, all the year round inhabitents of the mentioned areas /I/. In the present work are determined the concentrations of 16 trace ele- ments (Ce, Co, Cr, Cs, Eu, Fe, Hf, La, Mg, Mn, Rb, Sb, Sc, Sn, and V) in bottom sediments as an essential component of the chosen aquasystem. The re- sults obtained allow some conclusions on the eoological condition of the system and an assessment of the conditions in the environment. EXPERIMENTAL Sampling sediments The samples are collected from the upper 5cm layer of the bottom sediments together with fish from 5 points of Varna Bay and from 2 pointB of Saronikos Gulf in the summer of 1980. Treatment of the samples The bottom sediments are air dryed at room temperature for 8 days, them grinded in agate mills and homogenized after sifting two fractions are sepa- rated ( <0.05 mm <) by means of water-mechanical method by use of ATERBERG cylinders /2/; the time of the precipitation is calculated from the tables of KOSTER /3/. The carbonate component in bottom sediments is mainly biogenic. Analysis For the determination of all 16 elements was used instrumental neutron activation analysis (DTAA)/1/. The results are mean values of tree determinations with the respective standard deviations* AB a reference material was used geostandard TB (DDR) and standard solutions. RESULTS AND DISCUSSION The concentrations of the determined elements are presented in tables 1 - 3 in ppm dry weight. Table 1 gives the elements Co, Cr, Rb and V determi- ned simultaneously in bottom sediments and in flesh and liver of Gobius niger* While the Rb concentrations are Bimilar for both regions, cobalt, chromium and vanadium values are synonymously higher for S^aronikos Gulf* Additionally must be noted strong variability of Cr concentrations between all investiga- ted points. Table 2 presents the results of the determination of Cs, Fe, Mg, Mn, Sb , which could play *n important role from ecological aspect in connec- tion with human activity. Again must by noted a tendency to higher concentra- tions in bottom sediments from Saronikos Gulf, especially for Cs and Sb. The concentrations of the rare earth elements Ce, Eu, Hf, La, Sm and al- so Sc varys slightly for both regions as well as between different points. This is according to their origin, which exclude the influence of human acti- vity. 130 Samp- CONCENTRATIONS /ppm/ ling Points Co Cr Rb V A 1 2.43 + 0.17 33.3 + 2.2 63.5 + 2.3 14.3 + 2.1 2 4.10 + 0.23 19.0 + 3.8 54.6 + 4.0 16.7 + 2.6 3 U76 + 0.10 5.65 + 0.2 51.5 + 2.0 6.7 + 0.4 4 1.12 + 0.09 6.60 + 0.8 78.0 + 9.0 7.1 + 1.0 5 1.55 + 0.12 6.05 • 2.7 22.0 + 3.0 7.3 • 0.3 B A-10 22.4 + 3.5 150 + 20 76.0 • 1.5 90.8 + 20 A-3 15.7 ± 1.5 87.5 • 8.3 66.5 + 7.6 83.0 + 14 Table 1: Concentrations of Co, Cr, Rb and V in bottom sedi- ments from Varna Bay (A) and Saronikos Gulf (B) m BBSSEBBSB=S===BS ======:SESSSSSE=BBBasESESBBBBBSSB Sampi- CONCENTRATIONS"=/ppm/"= polnts Cs Fe Mg lin Sb X 1 1.16 + 0.06 8270 • 380 5700 +1360 186 + 13 0.42 + 0. 05 2 1.27 ± 0.05 13600 + 550 6130 + 1306 245 + 8 0.59 + 0. 06 3 0.78 + 0.06 6440 + 260 3100 • 1083 149 + 9 0.35 + 0. 04 4 0.87 + 0.03 4460 + 260 7590 + 2430 67 + 9 0.31 + 0. 03 5 0.43 + 0.04 4770 + 560 3970 + 1070 390 + 22 0.20 + 0. 02 B A-10 8.68 + 1.21 31800 +4600 23250 + 4500 2284 ±175 2.98 t 0.59 A-3 8.06 + 1.15 31000 +2100 23430 + 4400 362 + 29 3.89 + 0. 20 SSBaBBSBBBESSBSSBBBSBBBSBBSSBeSSBBSSBBBSBBSBSBSES Table 2: Concentrations of Cs, Fe, ttg, Mn and Sb in bottom sediments from Varna Bay (A) and Saronikos Gulf (B) Samp- CONCENTRATIONS /ppm/ lUg ' Ce Bu Hf La So Sm points A 1 60.3+3.3 0.73+0.-05 14.6+1.1 29.5+1.6 2.70+0,11 3.38+0.32 2 17.8+0.7 0.46+0,.04 81+0.08 9.8+0.6 3.10+0.12 1.54+0,17 3 8.2+0. 3 0.23+0,.02 0. 84+0.04 4.8+0.4 0.89+0.05 0.78+0,,08 4 11.7+1.3 0.26+0,02 1. 79+0.09 6.8+0.7 0.85+0.06 0.85+0,.05 0.81+0,>1O VJ l 14.9+2.0 0.28+0,.04 1. 37+0.17 7.1+0.7 1.04+0.10 B A-10 45.3+7.3 0.93+0,.05 2. 79+0.17 27.6+2 .1 9.7+1.4 3.60+0,.20 A-3 58.9+3.3 0.78+0,.07 1. 98+0,51 29.5+2.5 10.7+0.7 3.37+0,.23 -SBS"SSSSSSSESSS=E£!9SSSB Table 3: Concentrations of Ce, Eu, Hf, La, So and Sm in bottom sediments from Varna Bay (A) and Saronikos Gulf (B) 131 CONCLUSION The higher content of some elements in the bottom sediments from Saroni- kos Gulf could be explained by an intensive human activity concentrated in the area of this gulf (navigation, shipbuilding, chemical industry and others. In any case the high concentrations in bottom sediments bulgarian and greek are not reflected on the concentrations of the same elements in the flesh and liver of edible fish (Gobius niger), since in the latter the concentrations of the investigated elements are considerably under the recommended by WHO values. RfifSRBNCBS /I/. D. Apostolov, M. Iovtchev, L. Kinova, I. Penev, E. Taskaev, A. Grimanis, G. Kanias, C. Fapadopoulou, M. Vassilaki-Grimani, D. Zafiropoulos: "Studies of nine trace elements in flesh and liver of the fish Gobius ' ar from Varna Bay, Bulgaria and Saronikos Gulf, Greece (first part)" VII" Workshop on Marine Pollution of the Mediterranean, M»13.10.1984, Lucerne /2/. G. Miiller: Methoden der Sedimentuntersuchung, E. Schweizbart'sche Ver- lagsbuchhandlung, Stuttgart 1964 /3/. E. KSster: Granulometrische und morphometrische Mefimethoden, F. Enke Verlag, Stuttgart 1964 132 STUDIES OF TRACE ELEMENTS IN MARINE ORGANISMS FROM KASTELA BAY IN THE CENTRAL ADRIATIC M.Tusek-Znidaric, M.Skreblin*, J.Pavicicx, P.Stegnar, T. Zvonaricxx "J.Stefan" Institute, "E.Kardelj University, Ljubljana, Yugoslavia xCenter for Marine Research, Institute "R.Boskovic", Rovinj, Yugoslavia xxInstitute of Oceanography and Fisheries, Split, Yugoslavia INTRODUCTION Coastal seas are subject to the influence of local sources of pollution which can be considerable. This has effects on food production (fisheries, mariculture) and tourism; henoe it is important to discover more about the behaviour of various pollutants, their uptake and the mechanisms by which they are bound. In the present paper we present data on the concentration levels of As, Cd, Cu, Hg, Sb, Se and Zn in the muscle of fish and molluscs from Kastela Bay in the Central Yugoslav Jriatic coast, obtained by radiochemical neutron activation analysis (RNAA). In addition, in the mussel Mytilus galloprovincialis mercury was determined in other organs (gills, digestive gland, mantle with gonads, and muscle); by means of gel filtration chromatography, mercury binding proteins were isolated. EXPERIMENTAL For the analysis of Hg and Se, samples were sealed in quartz ampoules; otherwise poly- thene ampoules were used. The samples, together with standards, were irradiated in the Insti- tute's TRIGA M< II reactor for 18-20 hours at a flux of 2xlO12n.cm-2sec-1. The induced radio- huclides were separated by specific radiochemical procedures: As and Sb: - wet destruction in acid, extraction of their iodides with toluene /I,2/ - 69mZn, 115tnCd—-115rnIn, 64Cu: - wet destruction, extraction of their carbamates /3,4,5/ 197 75 - 7lHg and Se: - pyrolysis and volatilization, selective trapping on Se paper or soda lime, rescpectively /6,7/ For isolation of proteins /8/ the sapple was homogenized (suffer 20mM Tris-HCl, pH=8.6), centrifuged (27000 g, 1 hour at 4°C) and chromatographed on a column of Sephadex G-75, which had been calibrated with, chimotripsinogen A, myoglobin and cytochrome E. The absorbance of fractions from the column were measured at 280 and 254 ran, and then analysed for Hg. RESULTS AND DISCUSSION Table 1 shows the concentrations of As, Cd, Cu, Hg, Sb, Se and Zn in muscle of marine organisms, except for mussels, where all internal organs were analysed together. The results show that the levels of As, CU, Sb and Zn in muscle tissue of molluscs is considerably higher than in fish muscle, while the levels of Cd, He and Se are not appreciably different, except in mussels (Hg, Cd). The Bay of Kastela is polluted by discharges from a chlor-alkali plant containing inor- ganic Hg, which results in the relatively high concentrations of this element in all samples from tho area. The internal organs of mussels (Mvtilus galloprovincialis) strongly accumulate Hg, Cd and Zn, which is related to that feeding habit (filter feeders). Studies of the distribution and binding of Hs /9/ showed that the highest concentrations are found in gills and digestive gland (Table 2). For comparison, values from the non-polluted area of Strunjan are also pre- sented. In both organs, the majority of Hs is bound on high molecular weight proteins (Fig.l), which contain about 70 % of the total supernatant Hg. In distinction to Cd /10/, the low molecular weight, metallothionein-like protein fractions contain little Hg. It is possible that the high molecular weight proteins binding Hg are polymerized metallothionein-like proteins, or that the mode of binding of Cd and Hg in mussels is different. REFERENCES III A.R.Byrne: AnalyUChim.Acta, 59, 91 (1972). 121 A.R.Byrne, A.Vakselj: Croat.Chim.Acta, 46, 225 (1974). IV V.Ravnik, M.Dermelj, L.Kbsta: J.Radioanal.Chem.20, 334 (1974). /4/ M.Dermelj, V.Ravnik, L.Kbsta: Radiochem.Radioanal.Letters, 24, 91 (1976). 151 M.Dermelj, A.Vakselj, V.Ravnik, B.Smodis: Radiochem.Radioanal.Letters, 41, 149 (1979). Ibl L.Kosta, A.R.Byrne: Talanta, 16, 1297 (1968). Ill A.R.Byrne, L.Kbsta: Talanta, 21, 1083 (1974). /8/ M.Tusek-2nidaric, M.Skreblin, J.Pavicic, I.Kregar, P.Stegnar, A.Prosenc, VIIebJournees Eutd.Pollutions, Lucerne, C.I.E.S.M. (1984) (in press). /9/ M.Tusek-2nidaric, P.Stegnar, V.Zelenko, A.Prosenc, VI Journees Etud.Pollutions, Cannes, C.I.E.S.M. (1982). 110/ J.Pavioic, M.Skreblin, I.Kregar, M.Tusek-Znidaric, P.Stegnar, VIIesJournees Etud.Pollu- tions, lucerne, C.I.E.S.M. (1984) (in press). 133 Table 1: Concentrations of trace elements in marine organisms in mg kg-1 fresh weight, except Od and Sb which are in jug kg"-'- As Cd Cu HS Sb Se Zn Qupea sp. 5.55 17.8 0.02 0.16 1.36 0.72 7.23 Diplodus annularis 12.7 10.0 0.28 1.36 1.41 0.40 0.93 Gadus cepelanus 11.1 10.0 0.20 0.16 6.88 0.32 2.69 Nfcrluccius merluccius 11.5 - 0.10 0.17 2.04 0.26 1.48 Millus barbatus 16.5 10.0' 0.12 0.40 10.1 0.29 3.19 Pagellus erythrinus 2.34 10.0 0.15 0.82 1.65 0.43 1.14 Solea solea 3.74 10.0 0.07 1.20 2.31 0.52 1.90 Octopus macropus 25.3 10.0 2.10 0.26 36.8 0.47 8.65 Sepia officinalis 26.3 10.0 0.85 0.29 56.7 0.29 5.44 Loligo vulgaris 7.39 10.0 0.92 0.13 7.70 0.43 5.41 Ntytilus galloprovincialis 2.93 380 1.33 10.6 31.5 0.95 85.3 Table 2: Distribution of Hg in the internal organs of Mytilus galloprovincialis in mg.kg~l fresh weight Kastela Bay Strunjan tfe gills 26.4 0.03 digestive gland 20.2 0.10 mantle and gonads 3.68 0.01 muscle 1.70 0.02 Fig.l. Sephadex G-75 chromatograms of supernatants of mussel digestive glands (A) and gills (B). In 5-7 ml fractions total mercury ( ), absorbance at 280 nm ( ) and 254 run ( ) were measured. 240 40 Ve(ml) 134 MACRO- AND MIGROELEMENT DBTERMINATICK IN SOME SPECIES OS THE FAMILY FUMARIA. L. DISTRIBUTED IN BULGARIA L. Marichkova, 0. Kjostarova Institute of Nuclear Re search and Nuclear Energy Bui. Lenin 72, 1184 Sofia, Bulgaria INTRODUCTION Moat of the species of family Fumaria L. (rosopas) are widly distributed in our oountry. In Bulgarian popular medicine only the Fumaria officinalie L. (pharmaceu- tical roBopas) epigeous parts are used. The market drug consisting of the Fumaria L. epigeous parts usually contains not only the Eumaxla officinalie, but also other species of the same family. For that reason phy to chemical studies of morphologically similar species of the mentioned family were set about. It was found out that mor- phologically similar Fumaria L. family plants contain different alkaloid substances (6) and therefore they must not be replaced one by another. Taking in account that the Fumaria officinalis L. is used widly In our traditional popular medicine, the drugs have to be distinguished well one from another. The Fumaria officinalis L.plani is used also in USSR against different deseases (1). The mineral composition stuaing of different species of the mentioned family was of interest as this composition participates in methabolism of the human body. It was important to know whether the weak toxity of alkaloiden was not accelarated by the mineral one. In this paper se- ven Fumaria L. species are determined. The probes were collected in the bloom period near by Varna city. EXPERIMENTAL The macro- and mioroelement determination was carried out generally by means of neutron activation analysis nondestructivemethod. The measured species (probes and standards) were irradiated in Sofia IRT-2000 reactor for time periods according to radloaotive izotop activations. The elements: manganese, strontium and zirconium were determined using radioizotop X-ray fluorescent analysis for both the plants and the soils. Cd-109 source, Si(Li)-detector and Nokie multichanal analyser were used. The standards were prepared inour laboratory from pure chemical reactives for ana- lysis, as well as International plant standard "Kale powder Bowin" was used. The laboratory standards were dropped by means of absolutely precised "Etamiltonnpipets, California. The element quantity determination method was described in our previous works (3s 4, 5). RESULTS AND DISCUTICN In Table 1 the macroelement determination results in the epigeous parts and in the roots of the plants as well as the soils on which they grow are given. Erom the Table one can see that sodium is in greater amount In the roots than In the epigeoue parts. Potassium and calcium quantities are In greater amount In epigeouB parts than in the roots. The copper is a little more in the roots. The same holds good iron and zinc.The quantities of sodium, potassium and zinc in soils are in greater concentration than in the plants whereas the quantities of calcium, copper and zinc are in lower concentrations. In Table 2 the microelement quantities in the epigeous and root plant parts as well as of the soils on which they grow are given. Bromine and rubidium are accumu- lated more in the epigeous parts than in the root parts. The remaining elements are approximately of the same quantities in the epigeous parts and the roots. Mercury, arsenic and other toxic elements are not found in the plantB. The determined ele- ments are in admissible range for plant probes (3, 4,5). Farticulary usefull for the qualities of drugs are the elements: calcium, co- pper, zinc, potaBBlum,cobalt and iron. Legend It refers for the macro- as well as for the microelements Number of the probe Name of the species 1 Fumaria schramii well 2 Fumaria porvlflora Lam. 3 Fumaria vaillantii Loisel. 4 Fumaria kralikii Jordan. 5 Fumaria officinalis Lang. 6 Fumaria officinalie vor micrantha Lang. 7 Fumaria officinaliB vor olensiflora Parl. 135 Table 2. Macroelement quantities in the epigeous parts and in 1O# water extracts of some species of the Hypericum family in ppm. I-eoncentrations in dry weight epigeous parts in ppm Il-concentrations in 10# water extracts in ppm Number of 'E L E M E N T S the probe Na K Ca Cu Pe Zn 1 148,8 14480 9840 59,1 235,8 21,1 2 252,1 12540 9320 62,8 204,1 16,0 3 178,6 13810 11030 59,4 193,2 18,2 4 289,0 15120 12310 53,8 165,6 21,5 5 186,2 11850 8850 48,3 191,5 62,5 6 116,9 12760 8770 65,7 164,3 19,4 7 277,8 10540 9640 83,1 131,7 25,4 8 161,8 12330 12860 42,8 281,3 40,2 9 177,6 16180 10090 56,5 159,8 32,5 10 211,1 15430 8990 61,2 169,3 30,3 11 195,4 16950 9110 38,7 295,0 46,4 1 19,8 2340 1320 9,8 7,76 1,24 2 25,3 2180 1230 10,6 7,01 0,96 3 20,8 2040 1570 9,4 6,86 1,03 4 29,6 3210 1630 8,7 5,96 1,33 5 15,3 1980 1010 8,0 6,98 4,06 6 25,7 2230 1110 11,2 5,84 1,0 7 27,8 1860 1270 12,3 5,01 0,38 8 23,4 2180 1630 7,6 8,81 3,23 9 26,5 3480 1140 9,8 5,73 3,15 10 24,3 3040 1290 11,2 6,01 3,02 11 23,8 3540 1250 2»3 9,0 3,85 Table 3. Microelement quantities in some species of the Etypericum family I-concentrations in dry weight of the epigeous parts in ppm Il-concentrations in 10$ water extracts in ppm number of the E L E M E N T s probe Sm Cr Br Cs So Rb Co La 1 0, 068 0,152 8,27 2,,019 0,025 10,,28 5,,26 2 o. 021 0,767 14,,80 1,,037 0,026 ,89 2,,23 — 3 o,035 0,243 17,,83 0,027 17,83 1,,08 - 4 0,©40 10,,75 - 0,052 18,75 3,,73 - 5 _ 0,323 17,,64 6,,809 0,041 77,64 3,,17 - 6 _ 0,284 8,,59 - - 3B,59 0,,76 0,275 7 - 0,195 14,,19 3,,737 0,022 44,19 0,284 8 o,,092 0,505 18,,12 8,,799 - 21 ,47 0,252 9 o,,022 0,185 10,,15 3,,054 0,039 10,58 0,651 10 o!,084 0,181 1 1 j,02 4,,594 0,058 19,42 *• 0,384 11 o,,091 0,414 10,,57 2,,564 0,043 12 ,84 2,,86 0,579 1 o,,016 0,040 1,,23 o,,18 0,0021 1,53 o.,460 _ 2 o,,005 0,084 1,,97 0,,10 0,0022 2,64 o,,201 - 3 o,,007 0,042 2,,0B 0,0027 2,85 0 ,098 - 4 0,093 1,,69 * 0,0042 1,97 o;,324 - 5 - 0,049 2,,54 o,,58 0,0036 7,54 0 ,303 - 6 _ 0,038 1,18 • — 3 ,28 0 ,068 0,025 7 _ 0,035 2,06 o,,29 0,0025 4,56 - 0,019 8 0,,024 0,068 2 ,23 0,,73 - 2 ,77 - 0,018 9 o!,005 0,037 1,38 0 ,28 0,0037 1,18 - 0,668 10 o.,019 0,035 1,22 0 ,35 0,0043 1,86 - 0,044 11 o!,020 0,052 1,19 0 ,12 0,0032 1.19 0 ,243 0,061 136 Zirconium is found in almost the same quantities in both the epigetms parts and the roots. 0 Note The soils under the species N° 3f4,5»7 as well as under IT 1,2,6 are uni- ted as the plants are found in neibourhood and the Soil is one and the same for them. EEJBKSWCBS 1. H. AKOIIOB, KpoBoocTaHaBaHBajomHe paoTeHHH, 19,60, 93, TantKeHT. 2. E. AxTapoB, MaiepnanH aa 6uirapcKH 6oTaHHiecKH pemunc, 1939, 109, CO$HH 3. JI. MapHWKOBa H flp., $apMaijHH, 1976, 6, 34 4. JIi MapmKOBa H flp., 3>apMauHH, 1978, 4, 9 5. Jl. MapHMKOBa, A. BoeBa, VII HaUHOuaneH KOHrpec no $H3HOJiornH Ha 1980, 237, 242 6. H. Bvlogieva and oth. , Flanta Medlca, 1960, 1 137 / Application of Nuclear Analytical Techniques to Investigate Trace Elements Content in Foodstuffs A. Gharib Nuclear Research Centre AEOI P.O. Box 11365-8-586 Teheran-Iran ABSTRACT This work has been performed with the IAEA as a joint project in a coordinated programme on " Trace Elements in Human Nutrition and Bio-Enviromental Systems " to evaluate their nutritional requirements, interrelations and the role of Trace Elements in health, metabiolism etc,. This study includes those foodstuffs which are being used by almost everybody in all over of Iran. This is because of their essentiality and / or popularity, such as milk and breads ( wheat, flour, breads ). The later provides up to 70% needed protein of the people. The secondary aim of this project was the assessment of various analytical techniques involved. However, in the present work, the method involved were ASS, PIXE and NAA. The later method was applied, both instrumentally and radiochemically. The precision .for NAA allows greater degree of acceptance respectively. Although PIXE is a very fast and rather routine but the technique for trace elements analysis needs certain adaptations and development. 133 I' GEOLOGY 141 SOME REMARKS ON NAA IN GEOCHEMICAL RESEARCH M. Geieler Institut fiir Isotopen- und Strahlenforschung DDR - 7050 Leipzig, Permoserstrasse 15 INTRODUCTION Next year will see the 5oth anniversary of the first neutron activation analysis. In this relatively short time of only one or two generations of scientists this method has become a powerful analytical tool which can yield maximum outputs in various respects. Among the manifold fields of application, geology is one of the most important ones. This can be clearly seen by the fact that recently geological sections have been included in many conferences on ac- tivation analysis. There are various reasons for this. One of them is of course the great number of possibilities inherent in activation analysis. Secondly, the develop- ment of geology itself has contributed greatly. The different neutron sources ranging from portable isotopic neutron sources with a source strength of some 106 n'S"1 to nuclear reactors giving neutron fluxes of 1013 n-s'^-.cm"2 end more are suitable for analysis for concentrations from the per cent range of geolo- gical macrocomponent6 up to ppb or sub-ppb levels of trace elements. Some ele- ments, especially light ones, are analysed by fast neutrons of neutron genera- tors, and for some time elements of the periodic table having e low neutron activation sensitivity have been analysed by high-energy gamma rays generated by linacs and microtrons. Neutron activation analysis can be performed in geological bore holes, in ore dressing plants and on field exploration vans. But the neutron source used most widely for activation analysis, also for geological purposes, is the nu- clear reactor and will continue to be so in future. As far as the measuring aspect of NAA is concerned we do not find such a diversified picture. Equipment for geological analysis ranges from scintilla- tion counters to multi-chennel-analysers coupled semiconductor detectors. It is not possible here to deal with geological NAA in all its various as- pects. Rather I would like to restrict myself to reactor activation and make a few remarks on NAA in geochemicel research without pretending to give a comple- te and comprehensive picture. For this purpose it might be first of ell useful to have a look et the efficiency of NAA in geochemicel conditions. Then it will be easieer to define the position of NAA in geological research. Finally, the statements made will be illustrated by a few examples. THE EFFICIENCY OF NAA Sensitivity and detection limits ere some of the most interesting parame- ters of an analytical method. Sensitivities of NAA are tabulated frequently. Analytical detection limits LA containing counting detection limit Lc and sen- sitivity S as LA = VS are not of such general significance because the conditions of counting detec- tion limit are mostly idealized and related to pure samples, end therefore they are not valid for the large field of instrumental NAA (INAA). For this reason we will first of ell concentrate on sensitivity in our subsequent considera- tions. If an analytical method is to be appraised relating to a special group of samples, i. e. geological ones, then sensitivities should be combined with the typical contents of these samples. This has been done in Fig. 1. Of course it is not so easy to define the typical geological sample. In our investigations a fictive sample was used for this purpose containing the lithospheric Clarke concentrations, that is the mean contents of the elements in the whole litho- sphere. The lithosphere is generally Bssumed to contain 2 parts acidic and 1 part basic rock. These contents (in ppm) /I/ ere multiplied by NAA sensitivi- ties (counts per second and /ug element) taking into consideration the activa- tion of 100 h or up to saturation in 10±3 n.cm-Z.s-1, the intensity of the strongest gamma line and the detection effeciency of a medium size Ge(Li)-de- tector for this line. The product may be called Clarke sensitivity and gives the pulses per g of the fictive sample in the strongest line of the most active radionuclid of each element. These values are compiled in Fig. 1. Three different symbols are used to represent these values depending on the NAA technique mainly employed to determine an element in geological samp- les: INAA either by short irradiation in a range of minutes or by longer irra- diation of some hours, followed by measurement after some days or weeks, rasp., or as a third way, radiochemical separation before measurement. As a result of this marking procedure, symbols contain indirectly half-life relations and con- H2 dirions in the gamma spectra. Though Fig. 1 cannot give all details of NAA in geology, many facts of this field are immediately visible from it. Thus it shows very clearly the li- mitation of short irradiation INAA by Al and Mn and of long irradiation by Na and to a certain extent by La and Sm. Here we have the favourable circumstance that more than 20 elements can be determined instrumentally in geological samples which is mainly due to the fact that so many Clarke sensitivities are concentrated in a relatively narrow belt in the middle of Fig. 1 without having long-lived ones on top. Elements needing radiochemical separation are placed in the lower part and include both NAA-sen- sitive ones, such as Ir and Au, and insensitive ones, such as Ni and Zr having, however, high Clarkes. I would like to stress once more that the classification INAA - radioche- mical NAA is purely empirical, and certain experimental conditions can lead to variations in borderline cases. Such modified techniques ere i. e. epithermal noutron activation which has been increasingly used in routine work recently /2/, measuring of X-rays, or spectrometric coincidence measurements* Diagrams such as Fig. 1 can also be arranged for other rock types with variations occuring only in some elements in most cases. Completely altered re- lations are obtained for ores or special minerals. A second criterion for the assessment of an analytical method is the num- ber of elements analyzed. More than 20 trace elements in geological samples is a remarkable result for INAA. Only mass spectroscopy seems to be superior to it. However, it should also be noted that NAA is doubtless a multielement me- thod but without any survey character because sensitivity varies from element to element, and some important elements such as F or Pb are missing totally. If we include radiochemical separation procedures more than 60 elements can be analysed by NAA. This now touches another aspect of analysis - effort and expense in terms of equipment and manpower. NAA requires more specialized equipment than other methods as a nuclear reactor and conditions for radioactive working are necessary. Whereas in the beginning NAA was restricted to nuclear research centers only their irradiation lOt 90 Nftfl SENSTTTVITIFS FOR R GEOLOQICRL SfltiPLE REPRESENTED BY I. TTHOSF'HERIC CL.RRKE VfiLUES. STflGES OF GEOLOGICRL CONTENT OF NUMBER OF NUMBER OF HVfllLRBLE RND MINING RCTIVITIES THE ELE- SflMPLES THE ELE- TIME FOR MENTS DE- RNRLVSED MENTS DE- HNRLYSIS TERMINED TERMINED -FUNDRMENTHL RESERRCH* BfiSIC PROBLEMS OF FOR- \ CLRRKE \ < 180 \ MflNV \ MONTHS MRTION OF DEPOSITS \ -VflLURTION OF REQIONfiL DEPOSIT PROBfiBILITV -E^PLORHTION OF DEPOSITS -DEPOSIT EVfiLURTION -MINING PROCESS CONTROL V \ > 1800 ^ 1 * < HOURS ' • • • Sm FIG.2: REQUIREMENTS FOR fiNflLVSIS IN SEVERflL STFlGES OF GECLOGICRL RESEflRCH flND MINING out nearly independently. Nowadays the chain from basic research to practical mining is longer and also more compact. In Fig. 2 some steps of this chain ere compiled together with different analytical requirements. Fundamental geological research mostly far away from concentrations where mining would be worthwhile is the main field of geological trace analysis. Typical concentrations are in Clarice levels. Up to the present day one can find many articles about thie field in which sample numbers lower than 100 are analysed. These investigations are mostly of a relatively complex character and if no other methods ere included at the very least many elements are determined. Usually there is nb limitation in time available for carrying out the analysis. As far as the mining industry is concerned fundamental re- search is followed by evaluations relating to the possibility of deposits in lar- ger regions before local explorations take place. The last step is controlling the mining process. In this line concentrations increase up to those where mining is worthwhi- le which vary for different ores but ear. be in the per cent region. The number of samples to be analysed increases whereas the number of elements determined decreases. In exploration sometimes special indicating elements are used, and therefore not only the mining element is analysed. But at the face only the ore forming element is important. Looking at available analysis periods makes it clear: the nearer to the end of this chain the faster the results are needed. The position of NAA will become obvious from these considerations. The pa- rameters in the first line are the typical ones for reactor NAA. Multielement analysis in Clarke concentration level is its strong point as we have seen. In INAA decay periods up to one month till the last measurement are necessary. Therefore results cannot be obtained any faster. With that the close connection between NAA and geochemical fundamental re- search which we all know has become a little more founded. But the new tenden- cies towards increasing sample numbers by full automation open at least the next two lines in Fig. 2 for INAA in special cases. After that competing methods pre- dominate using bore hole logging techniques or portable instruments. Radiochemi- cal NAA is mostly used in fundamental research only. The share of trace analysis in geochemistry may be demonstrated by the fol- lowing numbers. Only 8 macroelements account for more than 99 % of the litho- sphere. the 8 next frequent ones for 0.9 % end all other elements together for less than 0.1 % /I/. We find much higher variations in trace elements then in macrocomponentB especially in equel or similar rock types. Therefore trace ele- ments can give information about more complex geological processes. On the other 145 hand we must not forget that in most cases we determine the trace content of the whole sample and not of individual mineral phases or even solve crystal structure problems for traces which all can be carried out for macroelements. At the beginning when I was talking about the reasons in geology itself for the success of NAA I had the following in mind. During its development NAA en- countered a geology changing from a more phenomenological and descriptive scien- ce to a measuring and calculating one. NAA stimulated this process in the same way as other methods. During this period of data collection geologists were and are interested in as many data as possible. All of us who work together with geologists know this tendency. It can be understood by the very complicated in- terpretation of geochemical or more general geological phenomena, always hoping that an element more could give a hint more. Recently, the next step has been taken more frequently: instead of a more or less empirical interpretation attempts are made to advance to the fundamental processses forming the complex picture of geological occurences. Because a satis- factory laboratory simulation is often not possible owing to extreme physical parameters geological processes have to be studied by their results in nature. This requires very complex investigation techniques including NAA among many other methods. In our institute these are physical age determination, investigation of sta- ble isotopes together with the study of liquid and gaseous inclusions. Most works are performed in close cooperation with geological institutions which con- tribute also their analytical methods. In such complex systems it ie important for the analyst to have good rela- tions to all coworking institutions for optimizing analytical tasks end tracing the results in the final interpretation. Although NAA offers a wide and manifold spectrum of possibilities in geo- chemistry some application fields stand out. Determination of rare earth ele- ments (REE) should be mentioned in first place in my opinion. This first place results from the number of publications, the geological importance of REE and difficulties in determination by other methods. It is possible to determine more than the half the REE in most rocks by INAA together with many other elements. If INAA fails i. e. in ultrabasic rocks there are effective radiochemical proce- dures to separate the REE group before measurement and determine nearly all REE. REE can provide information in connection with many geological problems. Their chemical behaviour ie very similar through the whole group (except Ce and Eu) but the varying ionic radii can cause different conditions for incorporating them into the crystal lattice. The measured contents ere usually normalized to the adequate contents in chondrites representing primary matter, or to other suitable samples. These REE patterns are interpreted, but unfortunately mostly in a qualitative manner only. This rather unsetiefactory situation results from the fact that the path of REE has not yet been explored quantitatively in many geological fundamental processes. Exceptions exist in en embryonic stage. Never- theless or even because q.f this REE should etey in the foremost position. A second main field is determination of very rare elements mostly in con- centration levels in which NAA ie superior to other methods by exhausting its whole sensitivity using radiochemical separation. Favoured objects here ere gold, rhenium and the elements of the pletin group. Contributions of NAA in establishing geochemical or similar standard refe- rence materials should also be mentioned as a third field. Let me unterpin my rather theoretical statements by som' small examples from these three fields. EXAMPLES REE IN GRANITES AND FLUORITES: In the western part of Erzgebirge (GDR) there are two large granitic intrusive complexes both including three intrusive phases. Their temporal order is established by geological fact6 and Rb/Sr age determinations /6/. The older complex (AG) is geochemically very similar to nor- mal granites. The younger one (3G) is highly specialized for some elements and connected with Sn-deposits /7/. More than 40 granites of these complexes were analysed for REE by INAA. Fig. 3 shows chondrite-normalized REE patterns of the three phases of the older complex (AG 1-3) as averages from several samples in each case. The slope of the patterns from La to Lu decreases through the phases 1-3. The Eu anomaly increa- ses. There are the same tendencies through the phases of the younger complex. In a diagram Eu anomaly (E) via slope (S), as in Fig. 4, homogeneousness and deve- lopment of the phases in both complexes are clearly demonstrated as well as the interposition of the intermediate granites 2G 1 end ZG 2. Increasing Eu anomaly in connection with other facts (low initial isotopic Sr-87/Sr-86-ratio) indica- tes increasing focal depht for younger granites. This nearly empirical interpretation of REE patterns is successfully trans- ferable to other granites of the southern part of the GDR. 146 0.5- terr. av. ^;* 100- E •ZG1 0.2- • ZG2 AG3 O.t 0.05- /• JG 2 10 *" Yb " " Sm+Tb 0.02' La Cc Nd SmEu Tb 2 5 10 20 FIG.3: REE IN GRANITES OF OLDER IN- FIG.4: DEVELOPMENT OF REE PRTTERNS TRUSIVE COMPLEX IN U-ERZGE- IN GRHNITIC INTRUSIVE COM- BIRGF 5- pigmotitic ' hydrothsrmat FIG.58 TB/CR-TB/'LB Dlfi- 2- GRflM OF FLUORITES FROM Pi PROF IL flT BOESENBRUNN.. VOGT- LflND <0DR> I I 5- 2- 0.005 0.01 0.02 0.05 0 fractionatron indtx Tb/la • 147 fn,mH^erSretatiSn °f REE*n fluorite mineralization is theoretically better founded and considers geochemical fundamental processes. We analysed many samples from a profile across a more than 2 mthick vein ^n ?h «rlte-?xne in the v°9tland region, GDR. We found very great variations hp H HPK 6r2S 6Ven °ver small distances in cm range. Some clarity could be provided by a diagram of the kind proposed by Holier et al. /a/ on the basis CS L fD™H n considerations on fractional crystallization including REE com- 5«m? ?f J A* 9,*L.5 ?hows thls dla9ram. The direction of primary formation is dominating in distribution of measuring points. Considering their order in the protiie it is possible to identify some cycles which were passed successively. S n c cle are I«nf? 5 k ° ! Y x especially marked in Fig. 5. These cycles were also confirmed by analysis of liquid inclusions (macroelement composition, isotopic ratios). On the basis of these facts in connection with the geothermal gradient determined by homogenisation measurements and by Na/Ca/K-temperetures of liquid inclusions a seismic pumping system is proposed as a model /9/. DETERMINATION OF OSMIUM: Os may serve as an example for an element requi- ring chemical separation. An osmium geochemistry has not yet been worked out be- cause there are to few data. But Os takes a part in Re/Os age determination. Du- ring previous preparation work for introducing this method in our institute our laboratory worked out a method for NAA determination of osmium in geological samples /10/. Separation is based on destination of Os as osmiumtetroxide fol- lowed by extraction in chloroform. A detection limit of 0.01 ppb is attained. MAA lu case of Os a rarelY appearing circumstance has to be considered in NAA. The isotope ratio in Os can be changed in Re rich geological samples by ra- dioactive decay of Re-187 (half-life 4.3*1010 y). NAA via activation of Os-190 yields only the non-radiogenic part of Os using a "normal" Os as NAA standard. This analytical disadvantage can give additional geologically relevant in- formation if the total Os content is determined by another method. This was rea- lized by Merz and Herr /ll/ as early as 1958 for molybdenites in higher concen- tration levels by spectrophotometry. First attempts in our laboratory by a cata- lytic total Os determination showed for instance ratios of radiogenic Os to non- radiogenic one in the order of 10:1 in samples connected with copper mining. Such combinations of NAA with other methods can give information in concentra- tion levels below typical working concentrations of mass-spectrometric isotope ratio determinations. ' NAA IN INTERCOMPARISONS: The best method and the only one under practical conditions to obtain information about accuracy of a trace analytical technique is comparing results of the same sample analysed by several laboratories using different analytical methods if possible. Such intercomparisons are organized by several institu- tions and partizipation can be PLACE LRB. RNflLYTICflL POINTS highly recommended. NO. CODE METHODS Participating laboratories are NO. supplied with extensive and de- tailed data from the final re- 1 56 NOT REPORTED 16 ports. But these reports do not or 2 49 Nflfi 12 only partly evaluate explicitely 3 30 Nflfl 11 the quality of laboratories and 4 33 Nfifl 10 methods. This is omitted because 5 43 XRF 9 quality criteria must have 6ome 6-9 22 Nflfi 3 arbitrary character among other 26 Nflfl 8 things. I carried out such evalu- 31 FlftS 8 ations for the lest two intercom- parisons in which our laboratory 45 Nflfl 8 • took part. They ere SOIL-7 from • the IAEA /12/ and fly coal ashes ECH, ENO and EOP from the Institu- • te of Radioecology and Applied Nu- 52-53 24 XRF -12 clear Techniques Kosice (CSSR) 32 flftS>RES -12 /13/, both similar to geological 54 41 fl«S>ET.flL. -16 samples. 55 42 RflS -22 56 15 flflS -28 I used the following evalu- ation. The accepted data of each element are roughly devided into Fro.6: BEGINNING FIND END OF LftBORfiLflBORA- three equal parts in order of in- TORV FLRCF.MEf4T LIST IN INTER- creasing value of results. Labo- COMPflRISON SOIL 7 ratories or methods having a re- sult in the middle part around the overall mean get a positiv point. Outliers produce negative points. Taking into consideration total numbers of positive points and outliers, one outlier gives about 2.5 ne- gative points. Fig. 6 shows beginning and end of the SOIL-7 laboratory placement list in- dicating a leading part of NAA. 5G laboratories partizipated in SOIL-7, 18 among them used NAA exclusively. But 8 NAA laboratories are placed among the 12 best ones. In the fly-ash intercomparison the respective figures are 34-10-7. But here laboratories in the two last places are also NAA ones. That indicates that NAA can also be performed in a wrong manner. Disregarding laboratories and evaluating only methods in SOIL-7 the order is: 1. NAA, 2. AES, 3. XRF, 4. AAS. In the case of fly-eshes NAA also holds the first place with advantage. This indicates that for this statement the kind of evaluation criteria is not so important. REFERENCES /I/ H. 3. RDSLER, H. LANGE, Geochemische Tabellen, VEB Deutscher Verlag fur Grundstoffindustrie, Leipzig 1965 /2/ R. 3. ROSENBERG, M. KAISTILA, R. ZILLIACUS, 3. Radioanal. Chem. 71 (1982) 429 /3/ K. KROGNER, 3. Radioanal. Nucl. Chem., Art. 83 (1984) 117 /4/ H. SCHELHORN, M. GEISLER, 3. Radioanal. Nucl. Chem., Art. 33 (1984) 5 /5/ M. GEISLER, H. SCHELHORN, Isotopenpraxis 18 (1982) 54 /&/ H. GERSTENBERGER, TH. KAEMMEL, G. HAASE, M. GEISLER, Preprint ZfI-14, 1982 /7/ H. LANGE, G. TISCHENDORF, VI. PALCHEN, I. KLEMM. W. OSSENKOPF, Geologie (Berlin) 21 (1972) 457 /8/ P. MDLLER, H. MAUS, H. GUNDLACH, 3h. geol. Lendesamt Beden-Wurtemberg 24 (1932) 35 /9/ H. KAWPF priv. comra. /10/ H. SCHELHORN, M. GEISLER, H. GERSTENBERGER, 3. Radioanal. Chem. 58 (1980) 239 /ll/ E. MERZ, W. HERR, Proc. Sec. Int. Conf. on Peaceful Uses of At. Energy, UNO Geneva, vol. 28 (1958) 491 /12/ L. PSZONICKI, A. N. HANNA, 0. SUSCHNY, Report on Intercomparison IAEA/ SOIL-7 of the Determination of Trace Elements in SOIL, IAEA Vienna 1984 /13/ M. KALINCAK. S. BARTHA, S. WIRDZEK, Report on Intercomparison ECH of the Determination of Trace Elements in Fly Coal Ash from Coal Fired Power Plants, Kosice 1984; item ENO and EOP 149 NEUTRON ACTIVATION ANALYSIS OF SOME ZIRCON SAMPLES FROM THE APU8ENI MONTAINS (ROMANIA) Maria Salagean, Ana Pantelici Institute for Physios and Nuclear Engineering BuohareBt MG-6. Romania V. Znamirovsohi, A* Mo$lu University of Cluj-Napoca, Romania INTRODUCTION Ziroon belongs to the isolated SiO* tetrahedra group of silicates, its salient feature of crystal struoture being the occurence of the unit cell as detached tetrahedral (SIO4)*- aniona. These tetrahedra stand isolated in the crystal struoture. none of the oxygen ions surrounding the Si ion being shared by the adjacent silicon-oxygen tetrahedra. From the chemioal point of view the Ziroon could be regarded as a salt of the hypothetical & SiO* add. The most important oations one finds in Zircon aret Oa2*, Pe2*, Al?+, Pe5+, Zr*+, Th*+, Nb5*, Ce3+, Hf*+, Y3+, U6*, Sn2+,0i*?+ and some rare earths. According to its formula the Zircon contains ZrOp-67,1 % (Zr-49,5 %) and SiO-32,9 %* Practically always it has a slight admixture of Fe20z (up to 0,35 % or more) often OaO (0,05 to 4 %) and sometimes AI0O3. It always contains hafnium oxide sometimes up to 4- % of HfO2, and in alvlte from Kragerb* (Norway) even 16 %. It may contain Y0O3 and rare earths, ohiefly Ce?05 (hagatalite) sometimes up to 16 %, with P2O5 content of 4- % to 5 % (amagutilite). Certain varieties may contain Nb and Ta (naegite), Th Ob up to 7 % and even 12 % in hb'gtveitlte. and also U3O3, up to 1,5 % and even more. It occasionaly contains negligible Sn and Be (in alvlte the content of BeO + AI2O3 may reach 15 %), Varieties containing a lot of P2°5 oxe known as oxyamalite, malacons and cyrtolites rich in radioactive substances and hence metaoict contains conside- rable amounts of Hjp (2 % to 12 %). Usually Ziroon occurs as small, rare, disseminated crystals in magmatic rooks. As a chemically inert mineral, Ziroon Is easily liberated from its ac- cessories In the course of weathering and passes into placers and hence as rounded grains, into sedimentary rooks. The X-ray investigatiog n of tht e Zircoirc n sampleaple s showhowss a typicatypia l radicaicall io- nic struoture comprising anionio SiQu. groups and Zr4"** cations surrounded by eight pxygen ions (fig.l). The SiQit cetrahedra alternate parallel to Ir with the Zr^+ions. The habitus of the Zircon crystal is short-columnar, often isometric, sometimes dipyramidal* The commonest forms aret the tetragonal prisms {100} ; {110} and the tetragonal dipyramld (111) (fig.2). Twins are genlculate like those of Rut He but ocour far less often. 110 Fig.l. Fig.2. The analysed samples come from the titaniferous placers of the N-NB-rn part of the VlBdeasa massif as the result of the weathering of daoites and an- deaites /I/* But it was pointed out that the highest concentration of ZrSlO^ ocour when the original rook is daolte and Zircon is almost missing when it is andesite. The spreading of titanium and airoonium minerals is closely related to the weathering extentlon of the daoites* The frequency of Zircon crystals is raising with the oontent of magnetite and llmanlte in the placers originated exclusively from daoites. Considering the extention of the dacites as well as old dacite quarries 150 and the frequency of the placers along the torents and rivers of the Apuseni Mts. this area oould represent a highly Interesting zone for the Industrial extraction of the Zircon. This mineral being the only source for metallic zir- conium, which has a wide use In technology, a more advanced study of this raw material absolutely necessary is considered. EXPERIMENTAL Using INAA the concentrations of 23 elements in a Zircon sample have been determined* The sample and SL-1, Soil-5 standards were irradiated for 50 hours in a thermal flux of l.lxlOlln/om2«8* for the long lived isotopes determina- tion* For Zr determination a ZrO» standard was used. She measurements were carried out by a Ge(Li) dateotor with 2 ksV resolution after 8 - 30 days coo- ,5 CM CD o CV 'A q in CN 122 1 CD r- 3 in o °* JD o - N 00 "cN &) 1 in \ 12 3 LD 3 I en in t^ CM S en CN T / 1 I \ ID ft CD 1 i 1 I f i Ji _J\._AIL»A. JL A ENERGY (keV) Figure 3* 151 ling time. In fig.3 a spectrum of the Zircon sample is presented. After an ir- radiation for 1 min. la a 2xl012n/om2.s. flux, short lived isotopes Al, Dy, Mn, Ti, V have been determined. W-l standard was used In this case. RESULTS ABC DISCUSSION The results of major and traoe elements concentrations are shown in ta- ble 1. The elemental content of Zircon concentrates proves to be extremely in- teresting for geochemists and petrologists /2/. The Zr/Hf ratio emphasizes the ori- TABLE 1 gin and affiliation of the Zircon to a certain rock type. The value of this ra- Element Concentration (ppm) tio (48.9) given in /?/ proves as Zircon bearing rock a granite that is an acidic Al(St) 0.72 + 0.04 rook. The Hf oontent is lowering in Zir- coas from alkaline rocks. From our re- Au 0.06 + 0.02 sults a ratio of 52.2 ± 4.5 was obtained. Oe 1694 + 115 According to /4/ where the Th/U ra- tio for different rock types is calcula- Co 2,0 + 0.3 ted, this ratio for acidic rocks varies Cr 12? + 32 from 3 to 4. Uranium content increases according to the acidity of the rock. For Dy 172 • 2 the examined sample this ratio is 2.5 + Su 26 + 2 0.4. It can be observed either a selec- *«(%) 0.88 + 0.13 tive concentration of the uranium inside Hf(*) 0.67 + 0.03 the Zircon lattice, or a rather complica- ted process by which these placers were La 1037 + 31 formad. Lu 59+6 A, high enough concentration of some rare-earths Ce, La, Nd, Tb, Dy, Sm, Lu, Mn 206 + 20 Su, Tb was found. Nd 732 + 130 The presence of certain minor ele- mtiits, as well as their content and res- So 63 + 5 pective ratios can provide a very pecu- Sn 105 + 7 liar key to put into evidence what one calls "geochemioal signature" allowing Ta 9 + 2 the geologist to identify those specific Tb 18 + 3 rocks and areas the Zircon came from. Th 514 + 26 Ti<*) 3.7 + 0,2 U 206 + 31 V 46 + 5 zr(%) 35.0 + 2.5 Yb 402 + 52 REFERENCES /I/ B.Stoicovici, H.Roth, Stud. core, geol-geogr., Clud, VIII, 1-2 (1957) 46 /2/ N.Korte, lI.Kbllenbaoh, S.Donivan, Analitlca Ohimica Acta, 146 (1983) 267 /3/ E.Rankama, Th.&.Sahama, Geochimla (1970) 511 /4/ P.Sentfle, N.B. Eeevil, TranB. Am. Geophys. Union, 28 (1947) 732. 152 DETERMINATION OF SOME RE E LEl'iENTS .SCANDIUM AND COBALT IN BULGARIAN GEOSTANDARD GRANITE G-6. E.Taskaev, D.Apostolov Institute of Nuclear Research & Nuclear Energy, Boul. Lenin 72, Sofia-11B4 H.Schelhorn Central Institute of Isotope and Radiation Research, Leipzi.j-7050, GDK Radiochamical separation was used for determination of content of some rare earth (RE) , scandium and cobalt in the Bulgarian geostandard Granite G-B. The RE and Sc were separated by precipitation as oxalates (i). Then Sc uas separated from the RE by extraction uith TBP. Co uas separated by extraction of its diethyldithiocarbamate complex uith CHC1... The resalts obtained uere compared with the data from INAA (2,3), AAS and X-ray fluorecence analysis (4). The standard reference material Soil-5 of the International Atomic Lnerrgy Agency uas analysed concurrently. EXPERIMENTAL Irradiation. Samples uere irradiated in polythene capsules for 20 h in IRT-2000 reactor in Sofia. Neutron flux uas 5.10 n.cm"/!.s~1. Samples' ueights uere about 250 mg. Solutions of RE, Sc and Co chlorides uere used as standards. •, Counting. ^-Spectrometer uith 26 cm GeLi uith resolution 2.3 kev at Co and multichannel analyser uas used. The samples and standards uere counted in 25 ml volume flasks. Counting time varied from 10 to 30 min. Dissolution.5ampj.es, after 5 days of cooling, uere dissolved in presence of carriers (50 mg of La, 10 mg of Ce, 1 nig of Sc and 1 mg of Co) and tracers (57-Co and 144-Ce). The mixtures of HF + HNQ3, (2ml : 1ml) and HF + HCIO4 (2ml : 1ml) uere used for the consecutive dissolution. Uhen the latter uao evaporatod the residue uas dissolved in about 20 ml of 2n HC1 ( + feu drops of H202)« Solutions uere trasfered from the platinum crucibles to the glass beakers. Separation of RE and Sc.About 5 g of NH4CI and 3ml of NH4QH uere added to the solution.lt uas heated and the RE and Sc hydroxides precipitates uere centrifuyed. The precipitate uas uashed uith NH4CI + NH4OH mixture and dissolved in feu ml of 6*7n HC1. The pH of the solution uas adjusted to 3+4 uith NH4OH and then about 10ml of saturated oxalic acid solution uas added, uhile heating and stirring. The precipitate uas separated and uashed uith 5ml of 0.1M oxalic acid. The oxalates uere destroyec uith tuo portions of H1MO3 + HCIO4 (1si) mixture. The solution uas evaporated and the residue dissolved in 10ml 10n HC1. From this solution Sc uas extracted uith tuo portions of TBP (5+5ml) saturated uith HC1. Bouth phases uere counted as the aqueous phase contained the RE and the organic phase - the Sc. The chemical yiBld uas controled in each sample uith 144-Ce for RE and uith irradiation of aliquote of organic phase (0.5ml) For Sc (5min in the above described conditions). Separation of Co. The solution left after the dBcantation of RE and Sc hydroxides uas dried. ThB dry residue uas dissolved in 10ml of CH3COOH and about 200 mg of each CH^COONa and NaDDC UBTB added. Co(DDC)3 uas extracted uith tuo portions (i0+10ml) of CHCI3. Chemical yield uas determined by 57-Co. RESULTS AND DISCUSSION The results obtained are given in Table 1. The data for Soil-5 ue obtained, shoued very good coincidence uith the ones given in (5). That alloued us to accept uith the confidence the data for Granite G-B. Table 1.Content of some RE,Sc and Co in ppm in G-B (6 individual determination) Element This uork. •X>2.SD Reference (energy) G-B Soil-5 G-B Soil-5 (2) (3) (4) (5) Sm 10 3kev) 3.50*0 .57 5.53*0.B6 3.5*0.b 4.3 4.6 5.42*0.39 Eu 1403kev) 0.92*0 .11 1.14*0.14 0.9*0.1 0.98 1.0 1.18*0.0B Lu 208kev) 0.22*0 .05 0.35*0.03 0.35*1). 0 8 0.41 0.5 0.336*0.044 Ce 145kev) 50.7*8 .1 61 .0*8.6 3R*2 48 48.5 59.7*3.0 La 1596kev) 21.7*3 .5 29.4*4.7 26*2 24 25 28.1*1.5 Yb 396kev 1,86*0 .29 2.04*0.34 1.8*0.3 2.24*0,20 Tb 299kev 1.65*0. 24 0.63*0.11 1.2*0.1 0.665*O,o75 Sc 368kev 5.83*0 .72 15.3*1.B3 5.6 7.0 14.B*0.66 Co 1332kB\i) 6.0*0. 9 14.0*1.5 7.0 5.4 7.5 14,B*0.76 153 The separation procedure for RE, using oxalate precipitation, was more time consuming than the extraction one (1), but in the case of standard material analysis, uhich is not serial, it seemed the preferable one to be used. On our opinion, that procedure allowed thB separation of the RE with less impurities. Undoubt advantage was the use of 144-CB and 57-Co tracers for the control of chemical yield. REFERENCE 1. Rjabchikou P.I,,V.A,Rjabuhyn, Analytical chemistry of RE and Y, Nauka, (1966) Moscou.pp 122-145 (in russion) 2. Apostolov D.,5,3ordanov, Nuclear Energy, 4 (1976) 77 (in bulgarian) 3* Rosenberg R., private communication 4. Iv/anov E1.A1., Geostandards Neusletters, V5, Noi (1981) 27 5. Dybczynski R., A.Tugsavul, D.Suschny, Report IAEA/RL/46, 1978 154 RAPID URANIUM ANALYSIS BY DELAYED NEUTRON COUNTING OF NEUTRON ACTIVATED SAMPLES N.N. Papadopoulos Nuclear Research Center "Demokritos" Aghiar Paraskevi 153 10, Attiki, Athens-Greece INTRODUCTION The neutron activation delayed neutron counting method for uranium analysis, in spite of its many advantages, as speed, accuracy, reliability, sensitivity, wide measurable concentration range, simple sample preparation because of non- destructive analysis, independence of matrix effects, low cost a.o., is applied only in a limited number of laboratories in certain countries. This is due, among other reasons, to past international disagreement on the usefulness of the method /^/ . Thus it was believed that the method can be applied routinely only for total uranium analysis, while it can also be used for cxtractable uranium determination, since for neutron activation and counting the sample can be either in solid or in liquid form. On the other hand, the conventional pneumatic transfer systems installed at most research reactors are not suitable for very short activation analysis, as in the case of delayed neutron measurements. Therefore a special system for short-lived nuclide analysis, with cyclic activation possibility for the improve- ment of sensitivity, had to be developed /2/. EXPERIMENTAL SET-UP The new home-made uranium analyzer (fig. 1) at the 5 MW swimming pool reactor of Nuclear Research Center "Demokritos", which was developed after more than seven years experience in uranium analysis, meets the special requirements of the de- layed neutron method, including a special pneumatic transfer system for short- lived nuclides with less than 2 s transfer time. It also has the possibility of cyclic measurements and covers a wide uranium concentration range from geo- chemical up to nuclear safeguards samples because of its flexible irradiation terminal, the variable sample size and other factors /3,4/. A double pneumatic tube for the transfer of samples in capsules of. variable size increases the de- terminable sample concentration range from fractions of ppm up to 100%. Thus, for dissolved geochemical samples of low uranium concentration, a double containment of 5 ml vials in 10 ml capsules is used. For highly enriched nuclear safeguards or other samples of high concentration, 1 ml vials in 5 ml capsules serve as con- tainers. The variable irradiation position at the reactor core with different neutron fluxes from 5x1011 to 5x1O13 n/cm2 s has been forseen to avoid too poor counting statistics or too high radioactivity release from the activated samples, or pulse pile-up during the measurements. For mineral samples of inter- mediate concentration, 2 ml vials are available. Thousands of samples have been analyzed so far. Since the analytical demand is increasing, complete automation of the system by a microcomputer is in progress. For testing the computerized automatic control system, a simulator of the analyzer has been constructed. The system will now be adjusted to the real analyzer. The control includes various functions, as sample loading, sample transfer to the reactor, irradiation timing, sample return to the counting station, counting timing and sample storage. In order to cover the wide application range, special operation controls are possible, as cyclic ac- tivation, simultaneous sample irradiation and counting of the previous one, tempo- rary storage after counting or irradiation during cyclic analysis, change of the counting end for v-ray spectrometry instead of uranium and thorium analysis by delayed neutron counting, a.o. For thorium analysis, cadmium covers are needed to increase the fast to thermal neutron flux ratio. With this automatic arranqe- ment the rate of uranium analysis can exceed 500 samples per day. For v-spectrum multielement analysis of short-lived nuclides, the ;:ate is less but stil compe- titive with other conventional analytical methods, while the sensitivity for a number of elements is higher. 155 RESULTS AND DISCUSSION Comparisons between the delayed neutron method for total uranium and the flu- orimetric method for extractable uranium analysis showed a relatively constant extractability, ranging from 60% to 85% (Table 1), while in the case of dissolved extractable uranium in low concentration rather large discrepancies have been ob- served between the two methods, so that further investigations are necessary (Table 2). The results between the delayed neutron and the x-ray fluorescence method (XRF) were in good agreement in the range between 100 ppm and 2000 ppm while beyond these limits some discrepancies have been observed (Table 3). For chemically enriched samples the results between the delayed neutron and the spectro- photoiretricmethod showed rather large discrepancies which have to be checked (Table 4). Uranium in lignite has been determined by the delayed neutron method and by gamma-ray spectrometry of natural radioactivity with good comparative results (Table 5). These intercomparisons show that the results of some methods are in good agreement while significant discrepancieshave been observed between other ones. This means that frequent intercomparisons are advisable, to check the reliabi- lity of the various methods. Thanks are depressed to E. Christodoulou, P. Kritidis, N. Gaitanis, G. Lefkopoulos, C. Gatsos, V. Lymberiades, N. Malliaros a.o. from N.R.C. "Demo- kritos" and to S. Gana, B. Perdikatsis from the Institute for Geological and Mineral Exploration, for their collaboration. REFERENCES /1/ R.G. GARETT, J.J. LYNCH, Proc. Exploration for Uranium Ore Deposits, IAEA and NEA, Vienna (1976) 321, 333. /2/ N.N. PAPADOPOULOS, J. Radioanal. Chem. 72 (1982) 463 /3/ N.N. PAPADOPOULOS, Abstr., Seminar on the Use of Research Reactors in Fundamental and Applied Sciences, N.R.C. Tajoura, Libya (1984) 44. /4/ N.N. PAPADOPOULOS, Abstr., Int. Conf. on Nuclear and Radiochemistry, Lindau, F.R.G. (1984) 169. Table 1 Comparison of total and extractable uranium analysis by the delayed neutron and the fluorimetric method respectively DN (tot.) FM(extr.) DN(tot.) FM(extr.) (ppm) (ppm) (ppm) (ppm) 52 32 184 125 32 26 288 175 18 12 328 229 45 27 1028 845 127 105 1700 1200 Table 2 Comparison of extractable uranium analysis between the delayed neutron and the fluorimetric method DN FM DN FM (ppm) (ppm) (ppm) (ppm) 4.8 2.3 10 3.2 6 3 26 13 4 2.5 6 1.6 8 3 8 5 15 6 10 4.8 156 Table 3 Comparison of total uranium analysis between the delayed ru'Ut ron and XRP method in ppm ON XRF DN XRF 22 358 333 17 560 573 132 1 J9 1112 1145 181 163 1708 1606 243 241 3993 3405 Table 4 Comparison of dissolved uranium analysis between the delayed noutron and the spectrophotometric method DN SP DN SP (ppm) (ppm) (ppm) (ppm) 28.5 43 40 43.5 8 3.0 63.5 6.5 0 39 3B 21 73.5 03.5 66 23 174 1.2 0 16.5 76 32 27 20 11.5 36.5 26 38 36 34.5 35 33 30 35 31 41 36 45.5 42 24 24 Table 5 Comparison of total uranium analysis between the delayed neutron method and gamma-ray spectrometry in ppir GS DN GS 31 32 20 26 29 30 69 6B 2.4 2.2 63 60 2.4 1.B 23 24 29 31 23 25 Cn • Neutron Counter Gamma Counter CV " D - Diverter L - Loader P = Pump R = Reactor RL = Reloader S = Storage TS = Temporary Storage V = Air Valve V * Capsule-Air Valve Fiq. 1 Uranium Analyzer 157 REE GEOCHEMISTRY OF THE STARA PLANINA OPHIOLITE ASSOCIATION L.Daieva, I.Haidoutov Geological Institute, Bulgarian Academy of Sciences "AcaU. G. Boncev atr.", bl. 24, 1113 Sofia, Bulgaria INTRODUCTION The Stara pianina ophiolite association crops out in the core of westermost part of the alpine Balcan range (Ntf Bulgaria), it is represented of stratified se- quence, consisting of units of cumulates,sheeted dykes and pillow lavas. Two subun- its are distinguished in the first one; the cyclic one containing Iherzolites, cli- nopyroxenites and gabbros and the layered gabbro one. The relationships of these units are transitional. The ophiolites are covered by the sedimentary-volcanic Uerkovica Group. Caledonian age is supposed for the two sequences. Like most ophiolites the stara pianina ophiolite suite has undergone conside- rable alteration and greenshist facies metamorphism /I/. These alteration and meta- morphic processes have caused important geochemical changes,so that many present geochemical features could not be used to clarify the petrogenesis of rock types/2, 3/. Several geochemical studies have demonstrated that low-temperature alteration and hydrothermal metamorphism of basalts has either little effect on REE-abundances /2,V»<>r causes only relative increases in LREE /3,5,6/. Coleman /7/ shows that these elements are important for establishing the analogy of ophiolite sequences.In this paper a comparison of absolute and relative REE-abundances In the rocks from Stara Pianina ophiolite association with other ophiolites and modern oceanic crust is made. Detailed structural,petrological and geochemical data on that ophiolite association are presented in a previous work /I/. EXPERIMENTAL Samples from the following rock types have been studied; one lherzolite,one gabbro from the cyclic subunit, two from the layered gabbro one, three metabasalts, one plagiophorphirite from sheeted dykes, two pillow lavas and two keratophyres from Derkovica Group. La.Ce,sm,Eu,Tb,Yb,Lu contents of the rocks were determined by INAA. A sample USGS-W-1 was used as reference. The samples were TABLE I. REE content of samples from Stara irradiated for.18 h bg neutron Pianina ophiolife association flux of l,6xiO12 n/sm sec in ex- sample perimental reactor IRT - 2000,So- La Ce Sm Eu Tb 1 Yb Lu N» fia. Iron was employed as a flux monitor. The obtained relative 0,9 1,0 0,* 0,U2 nd 1 nd 0,04 error for the REE was from 3 to 10% except for Tb - 2O?4. The da- 1,2 2,6 0,1* 0,56 nd 0,3 0,0^ ta are presented in Table I. 8 !.<• 2,5 2,0 0,76 0,2 0,7 0,13 RESULTS AND DISCUSSION k 0,5 5,0 1,3 0,60 0,2 0,9 0,16 The three plagioclase-rich/l/ I 0,92 0,8 2,1 3,5 6,3 2,9 0,39 (35-65 vol%) gabbros - s.**6*8,'» 3 <».7 8,8 3,7 1,23 0,9 2,5 0,46 and the lherzolite - s.46 , have 3a 5,6 9,6 3,7 1.13 1.0 2,5 o,*ta the lowest REE-abundances from the whole association, in compa- 35 ^.0 8,0 li* l,kk 0,8 0,* 0,11 rison with Bay of Islands gabbros 5* 3,6 10,3 3,9 1,18 0,7 2,7 0,51 /k/ these from Stara pianina ophiolite suite have higher REE- hz 3,3 7,7 3,9 1,36 nd 3,3 0,53 abundances and are closer to the 58 15,2 29,2 2,9 0,76 0,1 0,5 0,06 gabbros from Troodos /2/. The chondrite-normalized REE-patterns 68 21.1 63,2 5,7 1,50 0,9 2,2 0,33 are characterized by relative IHEE-depletion and positive Eu- anomaly.(pig.l), which are com- mon features of gabbros from ophiolites and Mid-Atlantic Ridge. The chondrite-normalized REE-patterns of the three metabasalts - 6. 1,3,35 a"d the plagiophorphirite - 3 are with slight LREE-depletion and negative Eu-anomaly, typical for the ocean ridge basalts and island arc tholeites /2/. Pig.2 shows that the sheeted dykes (1,3,3*) are situated in the dykes field from Troodos and Bay of islands ophiolite complexes /2,k/. The both pillow lavas - s. 5°,k!l have similar £ REE as the sheeted dykes. Their REE-patterns are nearly chondritic with slight convex-upwards REE-distribution (F"i/T- 3),which follows the REE-patterns of pillow lavas in Troodos and Bay of Islands ophiolite complexes, such REE-paterns are found for mid-ocean ridge basalts and is- land arc volcanics /k/. 158 Both investigated keratophyres cut- ting the sheeted dyke unit - B.58,68 ha- ve higher £ REE among all other rocks in the suite. The REE-patterns (Fig-l*) are characterized with strong LREE-en- richment and slightly expressed negati- ve Eu-anomaly. such characteristics are common for the Ca-alkaline intrusives from this region - stakevski (1) and Svetinikolski granitoids (II,unpubl.d.) The REE-abundances in the investi- gated rocks from Stara Planina ophioli* te association are similar to those in analogous rocks from other ophiolite lo- calities: Troodos /2/,Bay of Islands/**/. Most of the analyzed gabbros in ophiolites have variable but lower REE- abundances than associated volcanics. Typically these gabbros have strong po- sitive Eu-anomalies with relative LREE - depletion. It is shown that cumulate Y» in rocks formed by accumulation of 6O"6 pla- I gioclase,25?6 clinopyroxene and 10$ or- Fig.l REE-pattern in the rocks from thopyroxene /&*/ from a liquid with REE- cumulate unit abundances similar to the sample 3 from the sheeted dyke unit have Eu-enrich - ments and LREE-depletions similar to gabhros from ophiolites. In terms of plagioclase,clinopyroxene /I/ and REE-abundan- ces this model is appropriate for the Stara planina ophiolite gabbros - s.*»6 ,8. The availihle petrolo*?ical data /I/, the REE-abundance (the highest one) and slight- ly expressed positive Eu-anomaly of s.k give us no reason to cla- sify this gabbro as a cumulate rock. The metabasalts from sheeted = W i S'r—-~ ^ J. -—* *^'^ m dyke unit and pillow lavas have y^Z.. J^V'''""''**1'^**^*:'"..—•••"5' REE-abundances nearly lOXchondri- '" ^ '' '- -" ^ ^^ JS* tes with relative LREE-depletion. This is characteristic for MORB and so we find unlikely that this diagnostic feature in ophiolite basalts is due to alteration and metamorphism /2,V especially be- cause oceanic low-temperature al- LO Ct teration processes preferentially increase LREE-abundances /3,5,6/. The comparison of the pillow la- Fig. 2 REE-pattern ir_ metabasalts of the vas and sheeted dykes REE-pat - sheeted dykes unit terns from Stara Planina ophioli- te association with the field of normal-MORB /9/ shows that the investigated metabasalts are in the upper part of this field (Fig.5). Such REE-abundances and chondrite-normalized REE-pattern can be found also in some unmatured island arc basalts /10/ and small ocean basin basalts /2,k/. The avallible REE^ta for the both keratophyres cutting the sheeted dyke unit are not suffi- cient proof to explain their LREE-enrichment by oceanic low- 30 temperature alteration and green- shist facies metamorphism. It is possible,however,that this LREE- u|u to enrichment may have some connec- tion with later magmatic events in this region. sn eu Th Tk in Fig.3 REE-pattern in pillow lavas 159 CONCLUSIONS It is found that ophiolite rocks from the Stara Planina ophiolite association, Troodos and Ray of Islands have important REE similarities. REE-abundances of lavas, dykes and gabbros reflect a similar petrogenesis including a mantle source relati- vely depleted in LREE. Although these ophi- olite rocks have REE-abundance features si- milar to those of oceanic ridge rocks we concur with other autors /2,'«/ that only too- these data are not sufficient to distingu- ish between different tectonic environments such as deep ocean ridge, small ocean basin or an unmature island arc. La O Nd Sm En Tb REE-pattern in keratophires and Stnkevski(l) and Sveti- nikolski(ll) granitoids to C« Eu Tb tb L« Fig.5 Distribution of REE in dykes and pillow lavas compared with MORB-field. REFERENCES /I/ I.Haidoutov,L.Daieva,S.NedJalkova, Geotect., Tectonophys.,Geodin.,18(I985),1. /2/ R.W.Kay.R.G.Senechal, J.Geophls.Res., 81 (1976),964 /3/ I.Moody, can.Miner.,17 (I979)f871. /k/ C.J.Suen.F.A.Frey,J.Malpas, Earth Planet.Sci.Lett.,^5 (1979),337. /5/ Ch. Bonnot-Courtois, Chem.Geol.,31 (I98o),ll9. /6/ J.N.Ludden,G.Thompson, Earth.Planet.Sci.Lett.,^3 (1979)185. /7/ R.G.Coleman, Ophiolites, springer-Verl.,NY (1977),229pp. /8/ C. J.Allegre,R.Montigny,Y.Bottinga, Bull. Soc.Geol.Fr. ,15 (I973),'»6l. /9/ A.D.Saunders,Y.Tamey, Geochim.Cosmochini.Acta, 43 (1979),555- /10/ A.Masuda, Earth planet. Sci.Lett. ,k (1968),28I*. 160 POTASSIUM DETERMINATIONS IN CLAYEY MINERALS BY NEUTRON ACTIVATION ANALYSIS Lucre^ia Dinescu, Carmen Plaaada Institute for Physics and Nuclear Engineering Bucharest MG-6, Romania Abstraoti Seven samples of clayey mineral (illit) have been ana- lysed. Potassium oontents have been determined by IHAA, with a preoision better then 3.3 %. INTRODUCTION The knowledge of potassium oontent in minerals and rocks is very impor- tant for age determinations. The potassium determination is performed both by olasio and nuclear methods. The K-Ar nuolsar method is well known in age de- terminations* In this work the nuclear reaction (n, $T) for the potassium measurement has been used. EXPERIMENTAL Nuclear data for potassium and sodium are given in table 1. TABLE 1 T T.nfftnil Isotopio G"o *o p»nfln«+ I/P Photopeaea used Isotope abpgaano, parn parn Product 1/2 £aV 41K 6.7 1.46 1.42 ^K 12.36 1524.7 (17.9 %) zha 100 0.53 0*34 24Na 15.03 1368.5 ;2754.1 (99.85 %) The element sodium is given here to facilitate the understanding. It is a high disturbing element in potassium measurements. Powder samples of about 200 mg were weighted in small plastic bags which were heat sealed. Baoh bag was wrapped in aluminium foil. Standards were pre- pared in the same way as the samples. Kalium diohromicum - KgO^Oo (a hunga- garian produot) was used as standard. Illit mineral samples, togather with standards were irradiated 1/2 hour in 1.4xlOi5n/om2.s. flux* The samples have been irradiated both, without and with oadmium foil, but a significant Improvement in sensitivity was not ob- tained at the epithermal neutron irradiation. Measurements were carried out for 300-800 s, after 24 h cooling time. RESULTS AND DISCUSSION Seven illit mineral samples have been analysed by INAA. Potassium concentration in the sample was oaloulated from the formulae t c = ^e'f'>'"••• werei 0 - K oonoentration in sample, 0 - K oonoentration in standard, t - ti- me of sample measurement, ta - time of"standard measurement, A - the 1524 pho- topeak area in sample, A« - the 1524- photopeak area 1A standard, X =0*693 ™ The method preoision was oaloulated from the formulae! (2) werei n • number of samples irradiated from the same mineral (four in our case) Results obtained are given in table 2, along with the results obtained by the K-Ar method* The preoiBion was better then ± 3*3 %• A good concordance with the K-Ar results was obtained* The K-Ar method is sensitive and precise, but a very painstaking. The INAA is a simple and rapid method and the results precision is BatiBfaotory. The great disadvantage of this method consists in the fact that it cannot be used for the K determinations in minerals with high sodium oontent. 161 TABLE 2 Potassium concentration in illit minerals Concentration, % Sample K-Ar mothod IHAA method *yK (n.p) *9A 1 5.96 6.01 2 5.57 5.50 3 5.87 5.89 4 6.59 6.63 5 5.47 5.73 6 4.92 5.26 7 2.94 3.05 162 SIMULTAlEOnS HEUTRON ACTIVATION DETERMINATION OF ALOHIKIUli, MA&BESIUM AID SILICOH IB ROCKS Iv.Penev Institute of Nuclear Research and Nuclear Energy, Sofia, Bulgaria I.Kuleff and R.Djingowa Faculty of Chemistry* Sofia University, Bulgaria INTRODUCTION The determination of Al, Mg and Si in various types of rocks and mine - rals is very important for different geochemical investigations.Although wide- ly used for analysis of geological materials, NAA is not among the numerous analytical methods flj.osed for determination of the three elements, due to specific difficulties in the simultaneous determination of Al, Mg and Si. In the present paper a method for the simultaneous neutron activation determination of Al, Mg and Si in different kinds of rocks is described. THEORETICAL For neutron activation determination of Al the nuclear reaction 27A1 (n,ji.) 28A1 ( 1) is used.However Al is a product of two other nuclear reactions: 2SSi (n, p) 28A1 ; ( 2} 31P (n. o6> 28A1 . C 3> For the analysis of Kg, the reaction 26 27 Mg (n,AJ Mg ( 4) is of primary importance, but there are again two interfering reactions: 27A1 (n, p) 27IIg ; C 5) 30Si (tt,o6) 27Mg . C 6) ?7 This means that after reactor irradiation the two radionuolides Al and 'Mg are obtained as products of three nuclear reactions (.1-3) and (4-6) for Al and Mg respectively. In the case of Al, this may be expressed in the following way ' SA1 " V * Hp * H<* • ( 7) 28 where NA1 is total number of Al nuclei in irradiated sample, N^, B and N^ are contributions of reactions (1), (2) and (3) respectively.Absolutely the same may be written for Mg.The ways to solve this analytical problem are ge - nerally two £2,37: i, irradiation of the samples in a well thermalized neutron flux, which eliminates the interferences from reactions (2) and (3) for aluminium and (5) and (6) for magnesium. ii. repeated activation of the samples with neutron fluxes inadequate in respect to energy distribution: HA1 • •£ + V* "£ • (9) The system of equations 17-9) allows to calculate the concentrations of the elements of interest ( Al, Si and P in this case }, because the contribu - tions VC are proportional to the weight of the sample and the concentration of the X - th element in it. _ - The data of other autors J4.5J as well as our experimental results proved that the contribution of reaction (3) to the total number of 28-Al is negligi- ble. In most cases analogous is the situation with reaction (6)) in the analysis of Mg in rocks.This permits the solution of the problem for 28-A1 (resp.27-Mg) to be reducet to solution of a system of two equations with two unknown con - centrations after two irradiations and measurements: kAlCAl • kSiCSi + kiiGsi 163 where Cj is a concentration of the respective element in the material analy - sed,S is a signal received by the HPA froa the'analytical gamma-line for each irradiation, m are the weights of the samples for each irradiation and T1- the respective time factors: T = Ci-e3tp(-/4tB))expC-/6tc)(1-expC-^tll) , tB, tc and tM are respectively irradiation, cooling and measuring times, A is decay constant of the analytical isotope.The coefficients ki are determined experimentally using pure substances, for each type of neutron flux. Solution of the system (10,11) gives simultaneously concentrations of Al and Si in the material analysed.lt should be noted specially that the determi- nation of Si,, thuthuss performedperformed,, iiss considerablconsi y better then by use of reactions 30 Si .^ 31Si and 2929S i (a(,, p) 2299 A1. Concentrationtti s off M g andd AAll can be determined simultaneously in the same way using 27-Mg. EXPERIMENTAL Sample and standard pre ition.Samples of about 0.05-0.15 g were sea- led in- polyethylene capsules volume about 1 cm3.Pure substances - A12O« , SiO and Mg(CH^C00)2.4H20 were used as standards and were sealed in capsules (0.08 - 0.1 g ). The irradiation was carried out in the rabbit system of the experimental nuclear reactor IRT-2000, Sofia.The first irradiation was done with, eplthermal ( epicadmium ) neutrons using about 1.5 mm cadmium shield, and the second - with 5.1O12 cm~2.s"1 pile neutron flux.Copper monitors of about 5 mg were used to control the neutron fluxes. Measurement.The gamma-spectrometry measurements of the samples were carri- ed out with a QetLi) detector ( energy resolution 2.8 KeV, efficiency 8$ for 1332.5 KeV ), connected to a 4096 channel HPA Canberra-40.The gamma - lines , given in Table 1 have been used in the analysis.The measurements of the irra- diated samples started after a cooling time of 1 to 10 minutes, depending on the activity of the sample, when the total counting rate is 10* cps. Fig.1. Scheme of the method Sample J Irradiation tc- MOmin tM =300s tg-irradiation time, Standard NGpj/tB=120s tg-cooling time, tu-measuring time, N j-epithermal flux, !i Irradiation tc- MOmin tM = 300s Bth -flux of pile Nlh/tB-30s neutrons RESULTS AND DISCUSSION Analysis.The scheme of the proposed neutron activation method for simul- taneous deiermination of Al, Mg and Si is presented on Fig. 1.Geometry of spec- trometry and initial countig rate was keept invariable. Table 1. Analytical iBOtopes, Sensitiviti and Precision ELEMENT NUCLIDE HALF-LIFE GAMMA-LIMB DET.LIMIT REL.SD (min) (KeV) (mg/g) (S6) Al 0.03+ 2 Al-28 2.24 1778.9 Si 30++ 7 Hg Mg-27 9.45 1014.5 0.8++ B + - matrix 100$ SiO,! • ++ - matrix ioo% A12O3 164 Detection limit.The detection limits were calculated according to [jo] . The results are presented in Table 1 and may be accepted as satisfactory for analysis of various types of rocks and minerals. Table 2.Results of standard reference materials STANDARD C 0 N C S N T R A T I 0 N S ( % ) REFERENCE AlgO MgO SiO2 MATERIAL THIS WORK CERT.VAL. THIS WORK CERT.VAL. THIS WORK CERT.VAL, AH SSSR •» SGD-1A Cgabbro) 14.9+0.3 14.9+0.1 5.95+0.45 7.0+0.1 40.4+2.8 46.4+0.1 AH SSSR - ST-1A (basalt) 14.1+0.3 14.2+0.1 5.4+0.6 5.74\o.O7 47.0+3.8 49.1+0.1 ZGI - Gil (granite) 14.3+1.0 13.6+0.4 0.43+0.30 O.3B+O.13 75.4+8.5 73.5+5.1 USGS-PGC-1 (peridotitc)0.82+0.04 0.74 - 41.8+0.9 43.2 - 43.7+1.7 41.9 - ANRT-BB-N CRPG-1IA-(basalt)N 10.1+0.4 10.2+0.6 12.2+0.7 13.3+0.7 39.4+0.7 38.4+1.3 (granite) 18.3+0.5 17.7+1.1 -«=0.25 0.06 - 70.4±4.2 66.6+1.5 Accuracy and precision.The results from the analysis of different stan - dard reference materials are presented in Table 2. The are mean values of three parallel determinations, characterised with the respective standard deviations. The certificate values for the analysed materials are given as well.The good agreement of the experimental data and the certified values proves that the coditions of analysis ensure the obtaining of reliable results.The typical va- lues for the precision are given in Table I.It say be accepted as satisfactory for analysis of Al, Mg and Si in most types of rocks and minerals. Acknowledgement.this work was supported of the Ministry of Education of Bulgaria, contract mutter 16116. RBPBR5RCBS 1. P.Jeffery, Chemical methods of rook analysis, Pergamon Press, Oxford, 1970. 2. D.De Soete, R.Gijbels, J.Hoste, Neutron Activation Analysis, Wiley Inter - science, 1972, p.478. 3. K.A.Kryjenkova, U.G.Valieva, A.A.Kist, Rep.VINITI, Io.2192-70, Tashkent , 1970. 4. G.Brdtman, Neutron Activation Tables, Kernohemie in fiinaeldarstellungen , Vol.6, Verlag Chemie, Weinheim, New York, 1976. 5. P.Baumgartner, Table of Neutron Activation Constants, Karl Tiemlg, UUn - ehen, 1965. 6. L.A.Currie, Anal.Cham., 40 (1968) 586. all samples to be irradiated had the same geometrical shape and the same ' -["Parent" density. MULTIELEMENT NEUTRON ACTIVATION ANALYSIS OF SILICATE ROCKS USING SUCCESSIVE SHORT AND LONG SAMPLE IRRADIATIONS Irradiations. Samples are irradiated in Thetis Research Reactor (Gent, Belgium) during 5 minutes and then, after few Jays cooling, for about 7 hours. P.Vukotic, S.Jovanovic Short irradiations were carried out in a reactor channel Institute for Mathematics and Physics, with well thermalized neutron flux {<&.. =1.8. lo n.cir .s , University "V.Vlahovic", Yu-8looo Titograd, Yugoslavia _ _ tn ' REFERENCES Count!na schepe 1. J.BARTOSEK, F.ADAMS, J.HOSTE, Nuel.Instr. Methods, lo3(1972;iJ5. Count Coollnn set tine Detector Countina tine 2. N.G.GUSEV, P.P.DMITRIJEV, Kvantovoje izluchenije radioaktivnih nuklidov, Atomizdat, Moskva 1977. 1 15 m Coaxial 8 m 3. P.VUKOTIC, J.Radioanal. Chem., 63 (1981) 353. 5 roin.Irra- 2"5 Planar 35 diation 2 m m 4. P.VUKOTIC, J.Radioanal. Chem., 78(1983) Io5. 3 ca.3h Coaxial 15 rn 5. J.HERTOGEN. J.DE DONDER , private communication. Planar 6. F.J.FLANAGAH, Geochim. Cosmochim. Acta, 37(1973) 1189. 4 5-6 days Coaxial 50 m 7 hours Irra- Planar 5 1?. davs 1 h 7. K.GOVINDARAJU, I .HOELANDTS, Geostandards Newsletter, 1(1977)163. diation Coaxial 30 days Planar R h Coaxial "able 2. £ "adionuclirfes arv* their T-lineR nseH nr miantitative anal".<:l<; Table 3. to Padionu- I Count «?Pt naif-life2 P VaVT clide i r. ,Ke" : Planar CoaxiAl : i detector Hetectnr Spectral interferences corrected | ! - 24Na 15.005 h nsn.5, i732.n (nr> J.1," Anal"tical npak Interfering neak Comparator r>f>ak Radlonuclide 2Vcr 9.46 in mi4.4 : ! i F,V:e"2 28A1 2.24 n> 756.7 (DE) , 177.1.7 r 42 K 12.36 h 1524.6 51 1 Cr 32P.1 31".4147Tld 91.1147Nd 47Pc(Ca) 3.40 d 159.4 ! 4 ! j 153 ZJ 46Sc 83.8 d 889.2, 1120.5 : 4,5,6 R. 103.2 i 106.1 I!n 51 2 1 iss,, Ti 5.80 n 319 1 97.4 9n. 52 V 3.76 m 1433.9 233 103.2 101.n na 51Cr 27.73 d 320.1 160 56«n 2.578 h 84G.6 1 3 Tb 8f .n 59 !i » 170 Fe 45.1 d 192.2,1099.3,1291.6 5,6 5,6 n ion.1 60Co 5.272 y 1173.2,1332.5 **** 18.66 d 1076.6 Pha 11. R d 123.7,496.2 140La 40.22 h 328.8,487.0,815.8,1596.5 4 i 4,5 14lCe 32.50 d 145.4 4,5,6 '. 147Md 10.98 d 91,1 4,5,6 153Pm 46.44 h 69.7, 103.2 4,5 4,5 152EU 13.2 v 121.8,244.7,140^.1 4,5,6 | 5,fi 153 rd 241.6 d 97.4,103.2 P 1 1607b 72.3 d 86.8 5,6 : 165Dv 2.334 h 94.7 ' 2 1,1 166Ko 27.00 h RO.6 4 170Tm 128.6 d 84.3 6 169Yb 30.7 d 63.1 4,5,6 175 vb 4.19 d 232.5 5 4,^ 177Lu 6.71 d 208.3 4,5 '. 4,^ |181Hf 42.4 d 113.0,136.2,4*2.0 4,5,6 • 5,« 182Ta 115.0 d 67.7,100.1,152.4,1221. •» ! 5,6 fi 233Pa(7h 27.0 d 94.7 (OT^j) ,9B. 4 {"!<„.,) ,111.1 4,SO ! 4, "•.,« 230 4 Mnfr;, ?.-"55 <1 116.1 '" 1 Table 4. Concentrations in the silicate rocks investigated 169 DB'Jl w DCM ACV-1 r-2 x.(s.) X x (s X X X (s 5 Flana- V f'lana- l i» i i> ri 6 (4) qan nan (1) (2) (3) (5) (6) (7) (8) (11) * (in) * (9) (12) 2° 4.32(0.05) 4.33 3.39(0.04) 3.41 3.27(0.04) 3.27 4.19(0.05) 4.21 4.26 3.98(0.04) 4.04 4.07 4.36(0.05) 3.43(0.04) 3.31(0.04) 4.23(0.05) 4.10(0.05) 4.32(0.05) 3.24(0.04) O 4.2(0.4) 4,0 3.2(0.4) 3.2 - 1.8(0.2) 1.8 1.53 0.9(0.2) 0.0 0.76 4.1(0.4) 3.2(0.4) - 3.8(0.4) 13.6(0.3) 13.7 16.2(0.3) 16.1 11.8(0.2) 11.8 17.0(0.4) 17.0 17.25 15.6(0.3) 15.6 15.40 2°3 14.0(0.3) 16.0(0.3) 11.8(0.2) 13.6(0.3) 11.8(0.2) 0 _ - 2.0(0.3) 2.2 3.3(0.4) 3.4 2.R(0.4) 2.9 2.89 4.3(0.5) 4.4 4.51 2.3(0.4) 3.5(0.5) 3.0(0.4) 4.5(0.6) 3.4(0.4) o 15.4(0.4) 15.fi 4.8(0.2) 4.5 - 5.3(0.2) 5.0 4.90 2.1(0.1) 2.1 1.94 16.1(0.5) 4.2(0.2) - 4.7(0.2) 2.1(0.1) 15.3(0.4) 30.62(0.14) 30.68 17.51(0.08) 17.70 5.04(0.03) 5.02 12.2(0.1) 12.2 13.4 3.5(0.1) 3.5 3.7 17.91(0.00) 12.1(0.1) 3.5(0.1) m 30.95(0.14) 5.08(0.03) 30.46(0.14) 4.94^0.031 1.93(0.10) 2.01 0.67(0.07) 0.F4 0.99(0.06) 0.99 1.04 0.4R(0.05) 0.48 0.50 °2 2.09(0.10) 0.61(0.06) 2.02(0.10) Table 4. (continued) (10) (11) (171 (1) (2) (3) (4) (5) . (6) (7) (8) (9) 315(7) 322 105(5) 102 1 - 119(4) ', 119 125 38(3) 3P 35.' 330(7) 99(5) 320(71 r 15(1) 13 207(11) 210 10(1) i 10 13(1) 13 12.2 10(1) IP (7) 14(1) 210(10) 9(1) 13(1) 10(1) 11(1) 1872(19) 1R74 358(10) 850 97(2) 99 717(14) 717 763 250(7) 250 ?P1 im 1905(19) 840(10) 102(2) ._§___!__ _21Lll | C ! 11.37(0.06) 11.35 6.00(0.03) 6.1 0.95(0.01) 0.94 6.72(0.04) 6.70 6.76 2.64(0.02), 2.66 2.6 . 2°3 ; 11.41(0.06) 6.14(0.04) 0.96(0.01) 6.68(0.04) 2.68(0.02)! _2_2__2_2_1 38.6(0.3) 38.6 18.8(0.2) IB.7 0.75(0.02) 0.76 15.8(0.1) 15.8 14.1 4.5(0.1) 4.5 5.5 >m 38.9(0.3) 18.6(0.2) 0.76(0.02) 15.7(0.1) 4.5(0.1) 81 67(6) 66 67 157(14) 16? - 61(6) 60 79(7) — - 60(5) 84(6) 65(5) 166(12) >m 81151 - - 324(12) 318 368(24) 366 1237(30) 1213 1208 1898(45) ______312(13) 358(12) 1189(30) lflR9(45) 371_12l 13.2(0.2) 13.2 39.4(0.5) 39.3 (35) 89.9(1.0) 90.6 96 10.1(0.2) 10.1 22.3(03) 22.4 91.4(1.0) m 10.1(0.2) 22.4(0.3) 13.5(0.2) 39.2(0.5) 12.9(0. 2) 158(3) (15l> 24.7(0.4) 24.7 44.9(0.6) 44.7 29.0(0.4) 28.R 6R.4(1.3) 67.4 6 3 24.8(0.4) 44.5(0.6) 29.2(0.4) 66.5(1.3) 158(3) m 24.6(0.41 28.3(0.41 170 Table 4. (continued) (1) (2) (3) (4) (5) (6) (7) (in) (11) 19 .0(0.5) 18 .7 20.0(0.5) 20 .2 13.4(0.4) 13 .6 32.1(0.7) 31.6 39 53.1(1.1) 5 3.6 Cp" 18 .8(0.5) nnm 20.3(0.5) 13.7(0.4) 31.1(0.7) 54.0(1.1) 18 .2(0.5) 13.7(0.42 5. 72(0.04) 5. 71 •4.25(0.03) 4. 25 4.03(0.03) 4. 07 5.75(0.04) 5.72 •5.9 •?.0] (0.05) 7.T3 7.1: mm 5. 71(0.04) 4.25(0.03) 4.16(0.03) 5.70(0.04) 7.15(0.05) -Si 70(0.04) 4.03(0.03) Eu 1. 89(0.02) 1. 88 0.92(0.01) 0. 92 0.23(0.01) 0. 23 1.60(0.02) 1.60 1.7 1.33(0.01; !.,« 1 ."i 1. 90(0.02) 0.93(0.01) 0.24(0.01) 1.35(0.01) nnra 1.59(0.02) 1. 86(0.02) 0.23(0,01) 4 Cd 6. 0(0.4) 5. 1 4.7(0.7) 4. 4.3(0.6) 4. 7 4.8(0.3) 4.9 (S.S) 5.9(0.3) 6. ; opm 5. 0(0.4) 4.1(0.4) 4.9(0.4) 5.0(0.4) 6.R(0.5) 4. 4J0.6J. 4.810.42 Tb 1. 20(0.03) 1. 18 0.58(0.01) 0. 58 0.73(0.02) 0. 74 0.65(0.02) 0.63 0.70 0.41(0.01) 0.4B o.s 1. 0.58(0.02) 0.61 (0.02) opm 18(0.03) 0.75(0.02) 0.47(0.01) 17(0.02) 0.74j0.02)j Dv 7. 6(0.3 ) 7. 5 3.8(0.2) 3. 8 6.1(0.3) 6. 2 3.4(0.2) 3.4 2.1(0.1) 2.1 7. 4(0.3) pnm 3.8(0.2) 7. 6(0. i) Ho 1. 54(0.12) 1. 52 0.77(0.Of) 0. 83 1.17(0.09) 1. 14 0.74(0.08) 0.70 (O.fi) 0.38(0.06) 0. 1° (0. 1. 58(0.12) 0.89(0.07) 1.10(0.11) 0.66(0.07) 0.39(0.06) opm 1. 43(0.10) ._Iii§J2i22L Tm 0. 79(0.04) 0. 81 0.39(0.03) 0. 40 0.52(0.03) 0. 55 0.32(0.03) 0.32 (0.4) 0.21 (0.0?) 0.21 (0. 0. 80(0.05) 0.40(0.03) 0.58(0.04) 0.31(0.03) 0.21(0.02) c .85(0.05) O.56JO.O32 4.79(0.06) 4. 77 2.21(0.03) 2. 2.88(0.04) 2. 91 1.69(0.03) 1.70 1.7 0.7(1(0.0?.) 0.7" 0. 4.78(0.06) 2.22(0.03) 2.98(0.04) 1.70(0.03) 0.80(0.02) 4.74(0.06) 2.87J0.04) Tahle 4. (continued) 0) (2) (3) (4) (5) CM (7) (R) (9) (10) (U) c r.u 0.77(0.02) 0 .78 0.37(0.01) 0. 37 0.44(0.01) 0 .44 0.27(0.01) 0 • 2R 0 .2R OA2(0.01) o.i: 0.1 0.B0(0.02) 0.37(0.01) 0.45(0.01) 0.28(0.01) 0.13(0.01) _0i43J0iO12 3.94(0.06) 3 .91 3.63(0.05) 3. 67 2.25(0.04) 2 .27 4.97(0.06) 4 .94 5 .2 7 81(0.0«) 7.HP 7.T 3.93(0.06) 2.31(0.03) 4.90(0.06) 96(0.10) nnm 3.71(0.05) 0 .0 0 94(0.03) Ta 0.42(0.01) 0 .42 0.74(0.01) 0. 72 0.92(0.01) 1 .00 1.02(0.01) 1 .00 P.«1 — 0.41(0.01) 0.70(0.01) 1.19(0.02) 0.99(0.01) 0 92(0.03) 0.42(0.01) 0.90(0.01) Th 0.93(0.03) 0 .93 7.80(0.08) 7. 78 6.39(0.07) 6 .50 6.36(0.07) 6 .37 6 .41 24.4(0.2) 24.7 24. 0.95(0.03) 7.76(0.08) 6.69(0.07) 6.38(0.07) 25.1(0.02 nnm 6.42J0.071 U 1.06(0.06) 1 .06 2.26(0.10) 2. 23 4.09(0.16) 4 .18 1.99(0.09) 1 .92 1 .88 2 .01(0.09) ?.00 2.0 1.11(0.07) 2.20(0.08) 4.25(0.15) 1.84(0.08) 1 .12(0.0?*) nnm 1.00(0.06) 4.21(0.17) According to Flanagan, x is "reconended" value, x "average" and (x) "mamitude" of the concentration DITERMIHATION OF IRACB ELEMENTS IN FLT GOAL ASH (INO, IOP, BOH HIFBBBNOB MATERIALS) Maria S&l&gean, Ana Fantelioft Institute for Physios and nuclear Engineering Buoharest MG-6, Bomania Abstractt Oonoentration of 32 elements in three reference materials is determined INTRODUCTION This work presents the work regarding an intercomparison organised by the Institute of Radioeoology and Applied Nuclear Techniques from Eolice - Czecho- slovakia. By using the instrumental neutron activation analysis method the ma- terials of fly-ashes character from ooal-ftrad power plants was analysed. A number of 34 laboratories from 11 oountries have participated at this inter- ooaparison. IXFBRI MENTAL The concentration of Ba, Oa, Ce, Co, Or, Os, la. Fe, Hf, La, Lu, NA, Bb, Sb, So. Sm, Sr. Ta, Tb, Zh, U, Ib, Znf Zr was determined after a long irradia- tion ((55 0 hours) of the sampleap s in a tethermar l neutroeuton ffluux of l.lxlom/one.llloH s ThThe samplesmless (<(v 100 mg in weightiht)) an dd Soil-5Sil5 , SL-1SL1, GSPGSP-1 as standards, were measured 2-5 hours after a decay times of 10-30 days. Concentration of Al, Ast lu, K, Mm, Ha. Sm, Ti, V, Dy was obtained after a short irradiation of 1 min. in a 10l2n/om2.s. flux, ff-1 and arsenic oxyde ware used as standards. After 6 min.- 24 hours oooling time the samples and standards were measured for 100 - 1800 s., by using a Ge(Id) deteotor with 2 koV resolution. BI8UX0S AMD DISCUSSION The oontent of elements determined in this way are presented in table 1, 2, 3. for INO, 10F and 10H respectively. A, B class of results denotes the oertlfled values with satisfactory or acceptable degree of confidence respec- tively* Non reoommended values are denoted by 0* Our values are obtained SB arithmetic average from four Independent determinations. The standard devia- tion is given. Our results are in a good enough agreement with the oertified values. Only for Zn in INO material our value was rejected from the overall mean oaloulated. As there can be observed, a large oontent of arsenlum is present in the INO material. Our values for U concentration are systematically lower than the certified values. We have to oheok our method in analysing this element. For lu. Lu, Na, So in the I0F material our standard deviation is very small i.e. the four values obtained for each element being very dose. Also as one oan see our value for the Na oonoentration in the I0P material is higher than the oertified value. W* would suspect a small contamination in our mea- surements for this material. TABLB 1 - BNO Element "oncentration confidence limits Our results SesSts* 0 1 2 3 4 Al(Jl) 10.9 10.5 - 11*3 11.0 • 0.7 A As 1790 1680 - 1900 1643 +37 B Ba 674 630 - 717 690 + 78 A 0a(%) 3.3* 2.96 - 3.72 2.50 + 0.05 A Oa 98.7 93.2 - 104 92.5 + 1.5 B 00 26.1 24.9 - 27.4 27.7 + 0.6 B Or 96.1 88.0 - 104 92.3 + 0.8 A Oa 118 110 - 126 122 • 0.8 A Dy 7.02 7.52 S 0.27 0 Bu 1.76 1.41 - 2,11 1.77 + 0.09 A Fe(J6) 7.46 7.23 - 7.70 7.9* + 0.04 A Hf 4.89 4.64 - 5.14 4.46 ± 0.28 B 172 0 1 2 3 4 K(%) 1.73 1.67 - 1.78 1.64 + 0.06 A La 42.9 39.7 - 46.1 49.1 + 0.8 B Lu 0.54 0.50 - 0.59 0,57 + 0.02 B Hn 634 607 - 661 628 + 11 A Na(%) 0.54 0.52 - 0.57 0.54 + 0.01 A Nd 56". 1 40.5 + 7.6 C Rb 149 141 - 157 163 + 15 A Sb 5.72 3.68 - 7.76 4.49 + °»35 B So 20.7 18.7 - 22.8 21.3 + 0.1 A Sm 9.45 8.33 - 10.6 8.85 ± 0.18 a 3r 283 262 - 304 345 + 17 A Ta 1.22 1.17 - 1.27 1.20 + 0.02 B Tb 1.25 1.47 + 0.19 0 Th 15.3 13.7 - 16.9 15.7 + 0.2 B Ti(JO 0.46 0.42 - 0.49 0.51 + 0.08 A U 7.29 6.13 - 8.45 3.96 + 1.14 B 7 191 179 - 203 193 + 7 A Tb 3.49 3.14 - 3.84 2.85 + 0.10 B Zn 149 141 - 157 203 + 13 A Zr 222 170 - 274 246 + 33 B TABU 2 - 10P Blamant Oonoantration Oonfidanoa limits Our rasuits Glass of (ppm) rasults 0 1 2 3 4 •100 15.8 14.5 - 17.0 16.6 +0.3 A AS 79.1 72.4 -•85.7 77.0 • 3.7 A Ba 1100 1050 -, U60 1202 4 104 A OaOO 1.68 1.43 -• 1.93 1.83 + 0.13 B Oa 322 301 -- 343 306 + 1 A Oo 53.2 51.5 -• 55.0 56.7 + 0.5 A Cr 183 172 -• 195 188+2 A Os 20.1 18.4 --21.7 22.5 + 0.3 A Dy 10.8 9.8 + 0.1 0 Bu 4.99 4.22 -•5.77 5.20 + 0.00 A 5.16 4.96 ••5.36 5.55 + 0.04 A Hf 17.7 16.5 -• 18.9 16.3 + 0.4 B K(JO 0.64 0.62 •- 0.67 0.60 + 0.01 A 164 La 155 •• 173 170 + 2 A Lu 0.51 0.47 •- 0.55 0.52 + o.oo B Hn 440 409 '- 470 451 ± 16 A Na(*) 0.37 0.32 •- 0.41 0.55 + 0.00 B Nd 141 146 + 15 0 Rb 69.0 59.3 •• 78.6 94.7 + 3.3 A Sb 1.94 1.81 •- 2.07 2.15 + 0.36 B 173 0 1 2 3 4 Sc 36.7 33.0 - 40.3 40,8 + 0.00 B 6m 21.9 21.0 - 22.9 22.1 + 0.1 B Sr 574 535 - 614 475 + 40 B Ta 13.0 11.4 - 14.6 11.1 + 0.2 B Tb 1.93 1.34 - 2.52 2.62 + 0,29 B Th 23.9 21.3 - 26.5 25,6 + 0.2 A Tl(ff) 3.68 3.32 - 4.04 3.69 + 0.08 A 0 9.44 7.79 - 11*10 4.03 + 0.40 B V 553 525 - 582 568 + 11 A Yb 4.41 3.62 - 5.21 3*23 + 0.2x B Zn 219 191 - 248 337 +2 A Zr 822 701 - 944 841 + 89 B TABLE 3 - XOH Ilaaaat Glonoantratio n Coaftdaaoa limits Our results SiIStar Al(%) 14.6 14.1 - 15.1 13.7 + 0.5 A AS 56.9 52.6 -61.2 53.3 • 1.3 A Ba 711 636 -786 813 + 11 A Oa(») 1.86 1.68 - 2.0* 1.57 • 0.15 B Oa 183 174 - 193 169 i 6 A Oo 49.8 47.1 -52.5 52.4 + 0.9 A Or 183 174 - 193 183 + 2 A Oa 23*0 21.2 - 24.7 25.2 + 0.4 B Dy 8.80 9.40 + O.lfi 0 lu 2.95 2.85 - 3.0* 3.18 + 0.08 B '•(%) 5.57 5*40 - 5.74 6.00 + 0.06 A E£ 8.22 7.89 -8.54 8.13 i 0.40 B E(%) 1.32 1.25 - 1.38 1.57 + 0.16 A La 84.4 79.9 - 88.9 96.0 + 1.6 A Lu 0.61 0.57 - 0.66 0.62 + 0.01 B Un 381 358 •. 40* 394 • 3 A NaOf) 0.29 0.28 - 0*30 0.29 + 0.01 B Rd B5.7 82.0 + 7.8 0 Rb 141 128 - 155 162 + 7 A Sb 3.73 3.55 - 3.91 3.92 + 0.03 B So 29*2 26.8 - 31*6 31.0 ± 0.2 A Sm 13.6 13.0 - 14.1 12.8 ± 0.0 B Sr 401 366 -436 3B6 • 13 A Ta 4.37 4.09 -4.65 4.0* ± 0.12 B Tb 1.41 0.86 - 1.96 2.43 + 0.26 B Th 22.1 19.6 - 24.6 23.6 + 0.4 A Ti(%) 1.37 l.£'i - 1.50 1.08 + 0.06 A U 7*36 6.18 - 8.54 3.71 + 0.18 B V 375 352 -398 415 ±6 A tb 3.62 2.93 -4.32 3.01 + 0.27 B 174 0 1 2 3 4 Za 251 233 - 269 299 + 36 B Zr 361 291 - 430 497 + 77 A URANIUM OQMBHT M1ASUHIMI1ITS OR U-PH0SFHAT1 OBIS Maria S&lfigean, Asa Paatelloft, Stafanla Splridon Institute for Phyalos aad ffuolear Engineering Bucharest MQ-6, Romania Abatraoti Ooaoeatratlon of uramlua In 8-171 S-18 aad 8-19 rafaraaoa aatorlala haa baan dataralaad ualng the aeutroa aotivation analysia UKEBODUOTION The aaalytioal quality Ooatrol Sarvloa of IAIA haa orgaalaed this lnter- ooapariaoa oa thraa Braalllaa uraalua phoaphata oraa eoataialag a low, a u- dlua aad a larga ooaoaatratlon of uraalua ^S-17t S-18 aad 8-19 raapaotlvaly) la ordar to eartlfy thaaa aatarlala aa rafaraaoa aatariala aad alao to provide aa opportunity to tha participating laboratories to ooapara their aaalytloal aathodi aad reaulta with tha othera. A auaber of 24 laboratorlea froa 19 ooua- .trlaa have participated la thla latarooaparlaoa. 19 % froa the reaulta uaad tha neutron aotlvatloa aaalyala aethod. IXP1RIMIVZAL Valag the theraal neutron aotlvatlon aaalyala four Independent detaralna- tloaa far eaoh of tha three typoa of aaaplea have baaa perforaed by our labo- Ihe aaaplea with <^ 150 as la weight and uraalua aoatate (aqueoua aolution) aa a ataadard. have baaa Irradiated 10 hours la a LlxloJ-Wca^.e. flux aad aeaaurad for 1-2 houra after 6-7 days deoay time by using a Ge(Li) dataetor having 2 keV reaolution. BISULfS AHD DISCUSSION In the tabla tha oonoentration of uranium In the IAJA/B-17. 8-18 aad 8-19 phasphate urriiua oraa la presented and oan be recommended with a satisfactory degree of confidence. Material 0 8-1? 370 360 - 390 384+4 S-18 770 750 - 790 791 + 6 8-19 2280 2210 - 2390 2388 + 17 Our reBUlts are within of the oonf Idenoe limits given by IAIA after the evaluation of all tha received results. 175 DETERMINATION OF URANIUM AND THORIUM CONTENT IN ROCKS, BY BPITHERMAL NEUTRON AOTIVATION ANALYSIS Lucrefcia Dinescu, Oarmen Plamada Institute for Physios and Nuclear Engineering Bucharest UG-6, Romania Abstract! The epithernal neutron activation followed by gamma - apeotrometry measurements is used for samples with high Th/U ratios or high rare earth contents* The results of the IAEA intercomparison for S-14, 8-15, S-16 samples are given. INTRODUCTION The determination of the uranium and thorium in rooks is of interest in prospecting analyses and in more fundamental geochemioal studies. Thermal neu- tron aotivafion analysesf based on Ga(Li) gamma-ape otroma try provides adequate sensitivity for thorium in most oases when the aotivity measurements are car- ried on at least two weeks after the irradiation. The sensitivity of uranium determination by this technique is satisfactory for equilibrated Th/U ratios and low rare earth contents in sample analysed. When the Th/U ratio is increa- sed, the sensitivity of uranium determination is less satisfactory. The acti- vation with epithermal neutrons, using a cadmium cover to eliminate the ther- mal neutrons, gives rise to a considerable improvement in sensitivity for both elements, and especially for uranium, as can be seen from table 1. TABLE 1 Nuclear data for uranium and thorium Radionudid Io Product Used peafcs barn barn d keV 238-U 2.72+0.03 267+5 1.29+0.014 239-Np 2.36 228 | 278 232-Th 7.4+0.1 88+3 3.41+0.08 233-Pa 27.0 311 EXPERIMENTAL Powder samples of 0.100 - 0*250 g were weighed in small plastlo bags and the bags were heat sealed. Xaohtag was wrapped in aluminium foil. Rook samples, toghether with standards (prepared in the same way) were paoked in a 1 mm thiok oadmium box and irradiated for two hours in a 1.4xlOl3n/oB?.s. flux. Measure- ments have been carried out with a Ge(Li)-deteotor and the ND-6620 acquisition and processing system, after 6 days of cooling time for uranium, and 20 days for thorium. Measuring time i 1000 - 4200 s. Standards used i the IAEA 8-12 (UxOa t 0*014 %) for uranium, and a stan- dard of 0.99 % Th from Soviet Union for thorium. RESULTS AND DISCUSSION Five uranium rook samples with a high content of rare earths have been irradiated without and with a oadmium oover. The results have been compared with these obtained by delayed neutron analysis, that is considered the most sensitive method. Table 2 shows that the results obtained by ENAA are better than those obtained by INAA, TABLE 2 oOBnl, Delayed neutron INAA ENAA Al 70 55 66 h. 210 174 214 *3 260 223 264 *4 415 348 390 h 2245 2082 2256 Another possibility to check the validity of our results was to partici- 176 pata to the IAEA. Intarcomparison. In table 3 our results are given elong with the average established by IAEA, for three thorium ore samples 8-14, S-15, S-16, having a difficult matrix to analyse t high ratio Th/U (about 40 for 8-19, S-16 and about 20 for 8-14) and high rare earths content. TABLE 3 Concentrations of thorium and uranium in samples t S-14, 8-15) 8-16 IPIH IAEA •lament Units Sample concentration Concentration Confidence limits S-14 0,036 + 0.002 0.061 0.057 - 0.066 Th Wt % S-15 0,356 + 0.006 0.36? 0.351 - 0.374 8-16 1.641 + 0.025 1.680 1.620 - 1.750 8-14 24.1 + 2.0 29 26 - 31 jug/g S-15 76.5 • 3.1 85 79 - 89 S-16 454.3 + 8.0 445 427 - 468 The confidence limits are established for a significance level of 0.05. Table 3 speaks by itself on the validity of our BNAA method. 177 ACTIVATION ANALYSIS OF INDIUM USED AS TBAOTE IN HXDROGBOLOGY S.F. Stenescu, O.M. PfiroaBiu, S. Gaspar, Stefanla Spiridon Institute for Physics and Nuclear Engineering Bucharest MG-6, Romania V.M. Nazarov, M.V. Frontaeieva Joint Institute for Nuclear Researoh Dubna, U.S.S.R. INTRODUCTION From the aotivation analysis point of view, indiun has a series of pro- perties enabling a great improvement in the analysis sensitivity* the isotope 115-In has a high isotopio abundance a high value of the neutron aotivation cross aeotion (155 bn) and the 116m-If n isomer formed by aotivation is associa- ted with gamma radiations and has a oonvenable long half-time (54 mln.). When indium neutron aotivation analysis is preceded by a ohemioal-sre concentration (by oopreoipitation, for instance) a detection limit of lO^g/om? in the wa- ter samples may be obtained. Prom the hydrogeologioal point of view, indium is an element rarely en- oountered in natural waters, in small concentrations is not toxic and under the form of In-IDTA complex has a great ohemical stability. In this respect, indium oan successfully be used as a tracer In the hydrogeological studies. 1XPBRIHBNIAL Sample preparation and measurement method Starting with the results obtained by the german researcher* in the use of indium as a tracer /l/» an improved method of indium analysis has been ela- borated and applied in the hydro-karstic studies /2/« The water sampling has been carried on in 250 - 750 ml polyethylene bot- tles* The water samples were transported to the laboratory where indium was preoonoentrated by oopreoipitation with BiOE by the following procedure 1 - at 100 ml water sample 1 ml HpSQj. cone, and 2 ml Bi solution (10.7 g basio bismuth oarbonat dissolved in a mixture of 150 ml HNOx with 350 ml a>0 and then diluted to 1000 ml) were added} * - after 1 h, 7 ml NH^OH (25 *) was added; - the preoipitate thus formed, was filtrated through a nuclear membrane filter (holes diameter of 0.8 am) with a roughing pump and dried to ambient temperature 1 - the dried preoipitate was detaohed from the filter and was introduced into a polyethylene vial* In addition to the one presented in the paper /I/, the method used here has the following advantages 1 the method is simpler, the samples do not oon- tain the filter, and arc small in volume* 5 to 10 samples were at onoe Irradiated with a standard sample.(contai- ning about 15 ag In) 1A the nuolear reaotor at a neutron flux of lO^n/ooF.s. with the aid of an air rabbit* After an irradiation time of 20 - 60 minutes and a decay time of 15 minutes, the samples were measured with a Ge(Li) detec- tor having FWHM a 2.5 keV at 1332.5 keV and a multichannel analyser in 5 - 10 minuteB measuring time, quantitative determinations have been performed by cal- culating the areas of the 417*0 keV photopeak of the 116m-In isomer. In some conditions a detection threshold of 1.10-l2g/cm? for the indium in the natural waters was obtained. The samples measuring error was below 10 %, according to In concentration in samples, number of samples simultaneously irradiated and radiation back- ground givs£ by the other radioisotopes. In fig.l the gamma-ray spectrum for a sample of 1.10-l°g/em3 indium con- centration is presented. RESULTS AND DISCUSSION Practical applications The activation analysis of indium from natural waters was suooessfully ap- plied during the last three years in a series cf hydrological studies of some karstic structures from Romania /3-5/» About 2500 samples obtained from 18 wa- ter labelling* have been analyzed. The water flow rate values laid between 0.05 and 2.7 m3/s and transit time values were from 30 h to 200 days. The quantity of indium used for a labelling was oaloulated function of the emergences flow rate value and the estimated transit time and varied from 1 to 100 g. In fig.2 and 3 as an example two obtained water transfer ourves are pre- sented* 178 15 POO N /counts' Whonnel 10.000 846.6keV U9Nd 211.3keV 139 5.000 165JBkeV 2 116mIn 417.0keV 116mIn 116mIn i293.4keV 38 Cl 1097.1 keV 56Mn Ii368.5keV 1811,2 keV •*«4KLitf .,._l,,,,_j,_,.... Channel number 2048 Fig. 1 t(d) In fig.2 the obtained water transfer curve in the labelling with 100 g of indium of the sinkhole SOOROTA and followed by the water sampling from OERHA spring having an average flow rate of 2.7 mVs, are presented. We have obtained a transit time of 12 days. In the second experiment (fig.3) the water sampling was carried out on the TOPLITZA DB VIOA spring having an average flow rate of 0.075 mVs. The labelling was made In the sinkhole BIOHII with 10 g indium in the complex compound In-BDTA. A long water transit time of 40 days was obtained. From the interpretation of water transfer curves obtained by Indium la- belling, dates of a great importance about the karstic configuration of the investigated zones in mine and hydroteohnical works were obtained. CONCLUSIONS The aotivation analysis of indium in water samples combined with the pre- conoentration by copreolpitation proved to be an useful method in the UBS of indium as tracer in hydrogeological studies. 179 Besides the use of the fluorescent dyes and radioactive isotopes the use of In-EDTA as tracer proved to be a com- plementary method in the simultaneous la- belling and preferen- tially to use in the ease of the great water flow rate and long transit times when the use of an- other tracers is dif- ficult or impossible. The cost of the tracer and measuring activities is compa- 120 150 200 rable with that in- volved by radioacti- Fig. 3 tld) ve tracers, even the working procedures are a bit more trou- blesome. REFERENCES /!/ H. Eehrens, H, Uoser, B. Wildner, J. Radioanal. Ohem., 38(1977) 491 /2/ S.P. Stanesou, E. Gaspar, S. Spiridon, O.M. Farcasiu, R. Gatilina, Preprint IOEFIZ, HP 24 - Deoembrie 1982 /3/ S. Gaspar, O.M. Ffircasiu, 8.P. Stanesou, 8. Spiridon, Proc. First Symp. Theoretioal and Applied EarBtology, Buoharest 22-24 Aoril 1983 on /4/ 0. F&roaeiu, E. Gaspar, S.P. Stanescu, S. Spiridon, Proc. 2-nd National Symp. on Methods, Models and Techniques in Physios and Related Fields, Olud-Napooa, 14-15 Oct. 1983 B* Gaspar, S.P« Stanescu, I* Or&seanu, 0. Farcasiu, S. Spiridon, Proc. 2-nd Symp. on Theoretioal and Applied Karstology, Bucharest, 1-3 June 1984. 180 DATA ON THE REE, Th AND Hf - COVTENT IN /OLC.WIC ROCKS FROM CENTRAL CUBA I.Iordanov, D.Tchounev Geological Institute, Bulgarian Academy of Sciences "Acad. G.Boncev str.",bl. 2k, 1113 Sofia, Bulgaria INTRODUCTION The investigation of some authors /I,2/ shows that the Cretecious volcanics in Central Cuba am developed as an island arc system. In the volcano-sedimentary complex from this region two lithostratigraphic groups are distinguished: the lower one - built up from volcanic flysh and synchro- nously deep see low-K-&lealine volcanism; the upper - presented by volcanic molas- ses, accompaned mainly by subaerial volcanism, which is evolved from intermediate to acidic. For petrographical description the rocks from Central Cuba are subdivided ac- cording to their SiO2 -content /3/ into three groups; - basic rocks - basaltstholeiltic and trachybasalts, composed by pheuocrysts of plagioclase,pyroxene, olivine and amphibole. The groundmass of the rocks is de- termined as kryptomere to finegrained; - intermediate rocks - andesite basalts, trachyandesite basalts, andesites, trachyandesites and trachytes; - acidic - dacites, rhyodacitus and rhyolites, which represents the final stage of volcanic activity in Central Cuba. In this study we present additional geochemical data on the behaivior of the REE, Th and Hf in the rocks from the region mentioned above. EXPERIMENTAL Seventy one samples from basalts tholeiitic (Bth), truchybasalts (TB), andesite basalts (AB). trachyandesite basalts (TAB), andesites (A), trachyteandesites (TA), trachytes (T) and rhyolites in Central Cuba are analyzed. La, Ce, Nd, Sin, I5u, Tb, Yb, Lu, Th and Hf-content of the rocks are determined by INAA. The samples were ir- radiated for 13 h by neutron flux of 1,6X10*-^ n/sm2 sec in experimental reactor IRT-2000, Sofia. For the meaauremnts a Ge(Li)-detector with k9 sin active volume and 2,3 keV resolution (at 1332 kev of Co-60) was used, i sample USGS-AGV-l was em- ruble I Average trace element content of rocks from Central Cuba Lo Ce NdSmEu Tb Vb Lu La Th Hf K Ti Vb Bosoltstholeiltic (121 B.I 19.8 12 1.1 0,4 2,2 OP2.4 0,8 2,0 5500 4500 TrQChybQSQltS (24) qs2$ 15 SP1,3 05 2.3 3P 1.6 1.7 16100 4300 Andeslte bosaits (6) 10,6 16.4 14 8.1 1.0 Q5 2.2 3.1 1.8 2,5 12300 3300 frachyandesite basalfsQ "2,2 5.0 19 5,6 1.3 1,2 2.4 *° 3,4 2.1 2,0 28000 2640 Andesltes IS) 14,8 225 22 6,3 1.4 Q6 2,8 H553,5 3,1 33 18600 3500 Trachyteandesites (14) 18,1 1.8 18 8,4 1,1 0,5 2,6 •[45 4,7 2.9 3.3 27100 2800 Trachytes 32,4 525 17 8,5 13 1.2 4,0 07353 4,8 3.0 52900 2160 Rhyoleles (71 34,5B,7 25 8,5 043 1,4 3,7 0639,3 4,3 26500 2070 181 oloyed ns reference. The results given in Table I present :nean values of elements iletermined for each type of the rocks investigated. RESULTS AND DISCUSSION The chemical composition of the analysed rocks varies from low-K-tholeiites to high K-volcanics, which is consis- tent with their developnwnt in a ma- tured island arc /k/. with increasing K- and decreasing Ti-contents (Table!) from basic to acidic rocks in the complex, increased also the £REE (due to the LREE-enrichment mainly), Th and Hf-contents. For the two first members of the La Ce Nd sequence (basaltstholeiitic and tra- Yb Lu chybasalts) the chondrite-normalized REE-pattern v'Fig. I) is characterized with slight LREE-enrichment and abse.i- ce of negative Eu-anomaly in Fig.I Chondrite-normalized REE-patterns in basaltstholeiitic (BTh) and trachybasalts (TB). La Ce Yb Lu . 2 Chondrite-normalized REE-patterns in anilesite basalts (AB), trachyandesite basalts (TAB). the tholeiitic basalts from the com- plex. A slight negative Eu-anomaly is pronounced in trachybasalts. The LREE-enrichment and the negative Eu- anomaly become more expressed in the later members of this sequence: ande- site basalts and trachyandesite ba- salts (Fig.2); andesites and trachynn- desites (Fig.3); trachytes and rhyo- Lites (Fig.k). In the same way increa- ses;the(La/Yb) -ratio from 2,U in ba- Lo Ce Nd Sm Eu Tb Yb Lu saltstholeiititc to 5,3 in trachytes and 9,3 i» rhyolites. The last ones have the strongest negative Eu-anoma- ly, the most expressed LREE-enrich- Fig.3 Chomlrite-normalized RKE-pat terns in trachyainieaites (TA) and ande- sites (A). Fig.'* Chondrite-normalized REE-pat- terns in trachytes (T) and Lo Ce Nd Sm Ei Yb Lu rhyolites (R). 182 ment and the highest ITREE in the complex. A.t the same time a relative HREE-enrich- ment is observed. The characteristics of REE,Th and Hf for the rocks from Central Cuba discuss;-,i above are similar to the analougous rocks from Grenada, Lesser Antilles /5/. CONCLUSION The presented data for the behaivior of REE, Th and Hf in the volcanics from Central Cuba are in support of the suggestion of other authors /I,2/ for their de velopment in island arc system with eruption of basaltic lavas in deep see condi - tions. The evolution continued with formation of molasses in shallows condition rinii acfdic lavas in suhaerial environment. REFERENCES /1/M. Iturralde-Vinent, D. Tohnunev, R. Cabrera, Repport, Instituto de Geologia y paleontologia, 4cademia de Ciencias de Cuba, (19SI). /2/B. Echevaria, F. Talavera, D. Tchounev, I.iordanov, Repport, Instituto de Geo- lofjia y Paleontologia, Academia de Ciencias THE DETERMINATION OF THE SILVER CONTENT IN SOME ANCIENT COINS BY USING AN Am-Be NEUTRON SOURCE C.Coama.T.Fiat.V.Znamirovschi Department of Physics,University of Cluj-Napoca,Romania L.Daraban.V.Morariu Institute for Isotopio and Molecular Technology, Cluj-IJapoca, Romania Doina Boro?,D.Alicu The History Museum of Transilvania.Cluj-Napoca,Romania INTRODUCTION The investigation of the valuable metals of ancient coins, jewellery or others is useful for the purpose of gaining information on the economical status of a determinated historical period /1-5/. The ancient coins have a high historical and artistical value therefore their analyais should be performed by non destructive methods of analysis. The use of the surface analysis has a limited value as the coins may suffer elec- trochemical corrosion in time /5/« This phenomenon will result in noble metals enrichment of the surface. In the present paper the silver content of 40 Roman and Greek coins issued before and after the Roman conquest Dacia have been determined. EXPERIMENTAL METHOD The standard material and the coins have been irradiated in similar con- ditions in a thermal neutron flux from Am-Be source ( -10 n/s) by using a de- vice which ensures an Identical geometry for the irradiations /6/. The pure silver standard had a similar weight and shape with the analysed coins. The irradiated samples have been analysed by using a monocannel spectro- meter with a scintillator crystal Nal(Tl) having a relatively large size (45x40 mm). The spectrometer calibration was made by using the 662 keV energy of ^Cs as well as the 295 keV, 352 keV and 609 keV energies of pitchblende /!/. The coins were set on the entrance window of the crystal, in the center of it, the maximum measuring geometry being about 2lf. The measurements were performed with the help of a scintillation probe type VA-5-968 placed in a lead castle type VA-H-161 in order to decrease the background of the detector. The concentration, expressed in weight percent was calculated in the following way: m. I -F where m is the standard material weight (2.036 g), m is the coin weight (1.7-4 g), Im is the pulse number counted in the presence of the coin within the 550 - 720 keV energy range, I_ is the pulse number counted within the same energy range in the preaence of the standard material, F is the background pulse number within the same time and energy range. The 550 - 720 keV energy range was selected be cause two of the main gamma energies of silver are located within this range for thermal neutron ac- tivation namely 620 keV (108Ag) and 660 keV (110Ag) /B/. The above energy range was selected in order to avoid interference with the 511 keV peak of Cu which is also contained in the coins /9/. The 4J0 keV peak of Ag was neglected for the same reason. 184 The measurements were performed in the following way: 2 minutes for the irradiation time, 20 aec. for the cooling time and 1 minute for the measuring time. The ratio of the counting rate for the standard material and the back- ground was 2.5. RESULTS AND DISCUSSION The silver oontent of the 38 Roman and 2 Greek coins /10/ were included in table 1. The experimental errors about 5% for concentrations higher than about 5O5S and increasingly higher for lower silver concentrations. The metastable states of Ag and Ag have an unsignifiant contribution in the spectrum due to the small aotlvation sections and high value of the half life times.The Table 1. Silver content expressed in weight percents in some ancient coins The The silver s ilver No The ancient coins content No The ancient coins content ($5) 1 Denar,Antoninus Pius 89. 4 21 Denar(Severus Alexander 78 (140-143 A.C.) (222-228 A.C.) 2 Dena r,Ca ra ca1la 57.6 22 Denar,Caracalla 77 (196-198 A.C.) (196-198 A.C.) 3 Denar.Lucius Verus - 96 23 Denar.Blagabal 45.,5 (166 A.C.) (218-222 A.C.) 4 Denar,Marcus Aurelius 79. 9 24 Denar,Antoninus Pius 79.,5 (168 A.C.) (140-143 A.C.) 5 Denar,Geta 85. 5 25 Denar,Septimius Severus 91 (209 A.C.) (196-197 A.C.) 6 Denar,Septimius Severus 79. 4 26 Denar,Vespasianus 90 (198-200 A.C.) (74 A.C.) 7 Denar,Traianus 98. 6 27 Denar,Domitianus Caesar 3 (104-105 A.C.) (79 A.C.) 8 Denar.Vespasianus 86. 8 28 Antoninian,Philippus II 74..5 (74 A.C.) (244-246 A.C.) 9 DenartTraianus 96. 3 29 Denar,Severus Alexander 5 (102 A.C.) (231-235 A.C.) 10 Drahma,Dyrrhachium 91. 9 30 Denar,Caracalla 79 (III B.C.) (207 A.C.) 11 Denar,Traianus 99 31 Denar,Septimius Severus 80 (108-111 A.C.) (201 A.C.) 12 Denar,Caracalla 91 32 Denar,Traianus 12 (206-210 A.C.) (114-117 A.C.) 13 Drahma (Dyrrhachium 83. 3 33 Denar,Hadrianus 72 (III B.C.) (119-122 A.C.) 14 Antoninian,Philippus II 44 34 Antoninian(Philippus I 4 (244-247 A.C.) (248 A.C.) 15 Danar.Hadrianus 84. 8 35 Denar(Lucille 2 (128-138 A.C.) (161-180 A.C.) 16 Denar,Traianus 91.,6 36 Denar,Hadrianus 92,.5 (102 A.C.) (125-128 A.C.) 17 Denar(Traianus 91.,6 37 Denar,Severus Alexander 79 (102 A.C.) (222 A.C.) 18 Denar(Caracalla 66 38 Denar,Iulia Paula 87 (207 A.C.) (218-220 A.C.) 19 Denar,Ssverus Alexander 60 39 Antoninian,Hostilllanus 49 .5 (222-228 A.C.) (251 A.C.) 20 Plated denar,Antoninus 40 Denar,Severus Alexander 36 Pius (147-148 A.C.) 10 (227 A.C.) contribution of the °°Cu energies higher than 72Q keV by Compton effect is low because the activation section of HJU is one order of magnitude lower than for Ag. This is also due to the intensity of the nuclear transitions /ll/. The Fe and Pb isotopes may be ignored as they much less easily activated than Ag. 185 The coins no. 1-20 from table 1 have been discovered in the Roman camp of Gherla (45 km NE of Cluj-Napoca). This group consist of 16 denars, 2 Greek drahmas, one plated denar and one antoninlan. No false coins were identified within thia group and this could be easily understood as they probably belonged to soldiers. The coins no. 21-40 have been unearthed at Ulpia Traiana Sarmizegetusa, its being 17 denars and 3 antoninians. Several false coins are evident within this group (coins no. 27 and 29) as well as some historical unconalatencies (coins no. 28, 34, 35)• the greater diversity of the composition might be ex- plained by the fact that the plaoe where they were found was the administrati- ve centre of the province and an important trading place. The silver content show a maximum around the year 110 A.C. which is the flourishing period of the Roman Empire under Trajan emperor. This is also the post-Dacian wars (105-106 A.C.) period, when the gold and silver of the conquered Dacia flooded Rome /12/. REFEKENCES /I/ J.N.BARRANDON.J. Radioanal. Ghem., 55 (1980) 317 121 A.A.GOROUS, Archaeometry, 10 (1967) 78 I'M R.W.THIELE.U.AUNGHIN.U.KYAW, Archaeometry, 14 (1972) 199 IM CH.CHALOUHIj, E.HOURANI,R.LOOS,S.MELKI, Nuol. Instr. Methods, 200 (1982)553 151 C.BESLIU, V.COJOCARU, Preprint Univ. Bueureeti, CUP, 23, Mai 1982 161 T.PIAT.L.DARABAN, Studia Universitatis Babee-Bolyai, 21 (1976) 74 111 C.COSMA.I.MASTAM.V.ZNAMIROVSCHI, Stud. Cero. Piz. 33 (1981) 351 /8/ S.A.LIS,PH.K.HOPKE,J,L.FLASCHING, J. Radioanal. Chem.,25 (1975) 303 131 T.FIATfC.COSMA,L.DARABAN,V.MORARIU, The Vl-th Conference "Advances in physics", Sibiu, Romania, 1984, p. 640 /10/ H.MATINGLY.E.SYDENHAMM, Roman Imperial Coinage, London, 1923 1111 N.G.GUSEV.P.P.DMITRIEV, Kvantovoe izlucenie radioaotivnih nuclidov Atomiz- dat, Moskva 1977 /12/ J.CARCOPINO, L'or des Daces at les finances de Rome sous Trajan, Dacia, I (1924). 136 MONOSTANDARD ACTIVATION ANALYSIS OF PREHISTORIC COPPER OBJECTS V.Cojocaru,M.Ive§cu Institute of Physics arid Nuclear Engineering, P.O.Box MG-6, Magurele-Buchcreat, 76900. Romania C.Besliu University of Bucharest, Faculty of Physics, Bucharest, Romania D.Dimaerian Institute for Civil Engineering, Bucharest, Romania D.Popoviei Museum of National History, Bucharest, Romania INTRODUCTION Investigation on the composition of metalic prehistoric, objects has become more and more systematic in the last years. Among these the analysis of copper objects has to answer • series of questions concerning the ancient mining and pro- duction of metal. The most used method for the investigation of prehistoric copper objects was spectral analysis. By its means tens of thousand of objects were ana- lysed at the Stuttgard Museum /I/ and at the Institute of Archaeology of the USSR Academy of Science /2/. The sensitivity reported in ref./2/ is about an order of magnitude higher than that obtained at Stuttgart. It is to suppose that the neutron activation analysis (NAA) can be as simple as the spectral analysis but allowing probably lower detection limits, an advantage which ought not to be ignored. In order to demonstrate the possibilities of NAA on copper objects and to compare them with those of spectral analysis, especially from the point of view of detection limits, eleven eneolithic copper axes and other three objects have been chosen as investigation objects. Nine of these axes are adze-axes (cross-axes). The idea was to simplify as far as possible the method of analysis. With that end in view the monostandard activation analysis was used /?/• The reso- nance integrals used in this work were weighted averge values calculated on the basis of data from Gryntakis' and Kim's compilation /A/. EXPERIMENTAL Fragments from the investigated objects were cut with a special knife of hard steel resulting samples weighting between 2 and 20 mg. After a careful washing in pure alcohol each sample was wrapped up in a pure aluminium foil. These samples, the neutron flux standard, a nickel and two copper stanflarda were placed together into a quarts ampoule which was heat sealed. Irradiatiom was performed at the WR-S re- actor of the IPNE from MBgurele at an average thermal flux of 9.5xl012n cm-2e-l for 96 heurs. The two copper standards were pure metalie "Analar" copper with weights of 2 and 25 mg. Since their masses are more or leas equal to the minimum and maximum measea of the -investigated samples, the specific activity ratio gives an indication ef aelf-shielding affects of neutron flux and decaying gamma-rays in solid samples. Both the calculations /5/ and the experimental data show effeete smaller than 5 *• After irradiatiom eaeh sample was unwrapped, put in a clean vial and counted at a gamma spectrometer with a large Oe(Li) dcteeter with 1.8 keV fwhm for 1.9? MeV gamma-ray and a 4096 channel analyser. The counting was performed beginning with the 6-th day after the end of irradiation. The concentration of nickel was meaaured by means of 58Co(71.3 d) isotope produced by 58Ni(n,p) reaction, using the nickel standard. A correction was made for the contribution of the 67Cu(n,ot T60C© reaction when the concentration of cobalt waa determined. Thia haa been done by means of a pure copper standard irradiated together with the investigated samples. The results obtained by monoatandard NAA are given in Table 1. All the iaotopea meaaured here have long half-lives (more than 27 days) excepting 76AS (1.096 d) and 13bAu (2.697 d). These two isotopeB, especially 76AS, have to be counted during a few days from the end of irradiation. The are* cf 279.17 keV (20?Hg) photopeak was corrected for the interference given by the gamma-ray of 279.5 keV (25 %) emitted by '?Se, using for this the area of the 155.9 keV (58 fc) gamma-line of the same nuclidc. Since lead and bismuth cannot be analysed by NAA followed by gamma-ray apectros- eepy, all the objecta but nrs. 11 and 1? were investigated by aid of a X-ray spectro- meter with a Si(Li) detector having a resolution of 180 eV fwhm for K-Mn. No lead and bismuth could be detected at a concentration detection limit of 0.01 %. DETECTION LIMITS The sensitivity which can be reached in the instrumental NAA depends to a great extend on the purity of copper. Copper itself has two natural isotopes, «Cu and 65Cu, with abundance of 69.1 % and 30.9 %» respectively. In a reactor neutron flux they give (n.tf), (n,p), (n,oO and (n,2n) reactions. All resulting nuclides but 60c© have quite short helf-livee and 6 days after the end of irradiation 6*Cu (12-7 c 00 Table 1. Concentration of trace elementa in prahiatorio oopper objeota Sample Nr. of Se fin Zn Nr. inventory Aa Oo Or *• u Hi Sb 1. MIRSR 14050 0.0311 0.0057 0.00070 0.00013 n.d. 0.0120 0.0002 0.0020 0.0052 0.0074 n.d. ^0.0012 2. MIRSR 15687 0.0016 0.0014 0.00004 0.00004 0.0211 0.0400 0.0012 0.0040 0.0015 0.0023 0.1300 0.0042 3. MIRSR 32041 0.0860 1.762 0.00018 n.d. n.d. n.d. n.d. 0.0030 50.0002 0.1730 n.d. n.d* 4. MIRSR 15916 0.0022 0.0004 0.00012 0.00001 0.0008 0.0060 0.00004 0.0040 0.0003 0.0002 n.d. 0.0011 5. MTRSR 14049 0.0045 0.0160 0.00013 0.00001 n.d. £0.0050 0.00060 0.0050 0.0008 0.0050 n.d. 0.0016 6. Goll.Aparu 0.1140 0.0120 0.00094 n.d. n.d. ^0.0100 0.00020 0.0230 0.0021 0.0031 n.d. 0.0012 7. MIRSR 54045 0.0032 0.0032 0.00008 n.d. - ^0.0020 0.00010 0.0030 n.d. 0.0003 n.d. 0.0011 8. MIRSR 54751 0.0024 0.0026 0.00007 n.d. 0.0786 0.0026 0.0006 0.0080 0.0001 0.0017 n.d. 0.0011 9. MIRSR 14066 0.0014 0.0007 0.00002 0.00027 0.0060 0.0002 0.0120 0.0013 0.0002 n.d. 0.0016 10. MIRSR 15917 0.0009 0.0053 0.00003 0.00002 - <0.0020 0.00003 0.0070 0.0002 0.0004 n.d. 0.0013 11. Link I 65 0.0031 0.0008 0.00021 0,00002 0.0003 0.0032 0.00006 0.0090 0.0022 0.0001 n.d. 0.0018 12. MIRSR 39258 0.0095 1.565 0.00049 0.00014 n.d. 0.0060 0.00010 0.0060 0.0040 0.0014 n.d. 0,0016 13. Awl I 33 0.0052 0.0002 0.00011 0.00009 s 0.0002 n.d. 0.00040 0.0150 0.0039 0.0001 n.d. 0.0005 14. Rua/80 SIII 0.0470 0.1010 0.00006 0.00003 0.0025 n.d. 0.00010 0.0130 0.0023 0.0054 n.d. 0.0005 Table 2. Detection limita (56) obtained in inetrumeniial activation analyaia (IHAA) and apectral analyaia (SA) Ilenant SA IHM Element IHAA SA Ag 0.00005 0.0001 Mn 0.0005 0.01 Aa 0.0007 0.007 SI 0.002 0.0005 Au 0.00002 0.001 Pb 0.001 Bi - 0.0005 Be 0.00003 - Go 0.00002 0.001 8n 0.008 0.005 Gr 0.0003 - Sb 0.00004 0.0015 Fa 0.0026 0.001 Zn 0.0002 0.003 Hg 0.00003 - 188 h) activity diminishes 4.10-4 times fl&Aa activity decreases only a factor of 0.02) and the sample ean be counted. An element present in the sample in a high concentra- tion or/and large activation cross section ean mask an other isotope with a snail rate of accumulation. The situation is worse when the last one emits only one T-ray. The detection limits estimated in INAA are given in Table 2. The smallest con- centration* which could be measured by apaotral analysis /2/ for nore than 1200 sanples are also given for cemparation in Table 2. It ean be cosidered that the smallest determined concentration is quite elose of the detectien limit. Some values in Table 2 for NAA are taken on a similar ground. For manganese the detection limit was determined by 1 min irradiation of a eopper sample (10 mg) at the rabbit system of WR-S reactor (2xiol2n cm-28-l), using a decaying time of 1 h and e counting time of 1000 s. By means of INAA a number of 12 elements could be determined in a long irradi- ation run, the sane number as in speetral analysis. Six elements have a detection limit an order of magnitude higher in INAA in comparison with spectral analysis and only three have a lower detection limit (Pe, Ni, Sn). If the irradiation time is increased 4 tines, only tin remains with a lower detection limit. Furthermore, other three elements are seen with high sensitivity (Hg, Cr, Se) which are not reported in speetral analysis. DISCUSSION A number of 38 adze-azes found on the territory of Bulgaria has been analysed by Chernyh /2/ and all of then are framed in the six groups defined by him, the ma- jority being in the first group. In our ease only two axes ean be included in the first group, three in the eeeond group, but the rest of four cannot be placed in any of the Chernyh'e group. This fact demonstrates that these groups are not enough to characterize the copper objects from eneelithic. One can see that two axes have a high concentration of arsenic (between 1 and 2 %) indicating an arsenical bronze (eSn<0.4 %) /2/ produced deliberately in order to change the metallic proprieties of copper. It is interesting to try some supposi- tions on the nature of mineral which inserted arsenic in metal. In bronzing a high concentration of arsenic could be obtained by adding sulpharsenide minerals, such aa energite or tennatite, or sulphide .minerals such as orpiment or realgar. In eulpharsenidee arsenic, antimony and silver are geochemically associated, that is a certain ratio exists between their concentrations. As Goffer shown /6/ the concentration ratios As/Sb and As/Ag for copper objects found in the Dead Sea area are correlated. From the plot 11.6 of ref ./6/ one can infer that the correlation is where the elemental concentration is expressed in per cent. This correlation agrees very well for the axe nr.3, but not for the axe nr.12. On the Romanian territory energite and tennatite were identified in many places /7/. In conclusion it can be said that monostandard INAA is a rather simple and re- liable method. It has a sensitivity higher than spectral analysis, the processing of the spectra can be performed by means of a computer and an averege counting time of 1 h seems to be enough for a satisfactory statistics. Furthermore, it is not neces- sary to do any chemical processing on the sample, except maybe a slight etching and washing before, or even better after neutron irradiation. It is also an advantage that the sample is not destroyed. In this way it can be preserved or, if it is neces- sary, analysed again by NAA or some other method. All these advantages represent good premises for the prospect of studying many thousand of archaeological copper objects found on Romanian territory. REFERENCES /I/ D.Ankner, Auegabunnen in Deutschland, Teil ?, Mains 1975,p.145. /2/ E.N.Chernyh. Gornoe delo i metalurgia v drevneishei Bolgani.Igd.Bolgarskii Akad. Nauk, Sofia 1978. /V J.I.Kim and H.Stlrk, Activation Analyais in Geochemistry and Cosmochemistry. Universiteteforlaget, Oslo 1971,p.397• /4/ E.M.Gryntakia and J.I.Kim. J.Radieanal.Chen.76 (198?) 741. /5/ T.Takeuchi, Radioisotopes 29 (1980) 119. /6/ Z.Goffer, Archaeological Chemistry. J.Wiley&Sons, 1980 /7/ P.DBnila" and M.DBnilB. Cuprul. Ed.TehnicS. Bucure§ti 1982, p.38. 189 ARCHAEOMETRIC INVESTIGATION OF MEDIEVAL BULGARIAN GLASSES AND SGRAFFITO CERAMICS BY NEUTRON ACTIVATION ANALYSIS R.Djingova, I.Kuleff Faculty of Chemistry, University of Sofia, 1iH26-Sofia, Bulgaria The results from the investigations of the chemical composition of an archaeological find permit the reliable localization of its production, since the chemical composition of the analyzed materials is determined by the source the raw materials come from. The method most widely rased in provinience studies is NAA, due to its ability to determine a big number of elements with the necessary precision, accuracy and detection limit (see /1,2/). To solve the localization problem the data from NAA are usually subjected to suitable mathematical interpretation /i/. Already several years at the Faculty of Chemistry, University of Sofia in collaboration with the Archaeological Institute of the Bulgarian Academy of Sciencies archaeomefcric investigations are carried out wich include investiga- tions of medieval Bulgarian glass /3-5/ as well as of sgraffito ceramics /6/. INAA /'}/ has been used to determine the content of Au.Ba, Ca, Ce, Cl, Cr, Co, Cs,Cu,Eu,Fe,Hf, !La, Lu,Mn,Na,Rb,Sb.Sc,Sm,Sr,Ta,Tb,Th,Ti,U,V, and Yb in glass samples taken from the walls of glassmaking pots excavated from the medieval glassworkshops in Pliska (the first Bulgarian capital - 681-873) and Preslav (the second Bulgarian capital - 873-972) and in 20 glass finds from Preslav. By instrumental NAA /6/ 15 sgraffito ceramic samples excavated in Tzarevetz-, Veliko Tarnovo were analyzed and the el-em en ts Al,As, Au,Ba,Br,Ce, Co, Cr,Cs,Dy,Eu,Fe,Hf,K,La,Lu,Mg,Mn,Na,Nd,Rb,Sb,Sc,Si,Sm,Ta,Tb,Th,Ti,U,V, and Yb have been determined. The results from the analysis were subjected to cluster analysis and step- wise discriminant analysis using the program package BMDP /7/. Due to this approach the variety of the production of the medieval glass workshop in Preslav was defined and evaluated /^It's also proven that the chemical composition might be successfully used to differenciate between the production of the two workshops, which is very interesting having in mind the geographical closeness of Pliska and Preslav and the fact that both workshops actually functioned in one period of time. The combination of NAA and cluster analysis proved that part of the analyzed sgraffito ceramics samples have been produced in one and the same place (that is using one clay source). Since this production covered a period of 400 years (XV-XVIII c.) it may be supposed that it was locally made. Meanwhile along the Black sea coast and in some other places of Bulgaria a lot. of sgraffito ceramics has been excavated.Part of it is decorated with monograms, described in /«/. Similar finds are found in Constantinopole, Asia Minor, Thessaloniki,Roumania etc/9/. This poses an interesting problem to be solved whether these finds ware imported, or were local production with imitation of the same monograms. These investigations are now in progress. Acknowledgment. These investigations are possible thanks to the finencial support of the Bulgarian Ministry of Education, contract number 16116. REFERENCES /1/G.Harbottle, in: A Specialist Periodical Report "Radiocheaistry", vol.3, Burlington House, London, 1976,p.33. /2/I.Perlman, in; Nondestructive Activation Analysis, Elsevier Sci.Publ.Comp., Amsterdam, V981,p.259. /3/I.Kuleff,R.Djingova,I.Penev, J.Radioanal.Nucl.Chem.(Art.) ,83 (1984) 333. /4/I.Kuleff,R.Djingova,G.Djingov, Archaeometry-{ in press). /5/I.Kuleff,R.Djingova,I.Penev, Glastechn.Ber., (in press) . /6/I.Kuleff,R.Djingova,I.Penev, J.Radioanal.Nucl.Chem.(Art.) , { in press). /7/BMDP, Biomedical Computer Programs, Department of Biomathematics, University of California, Los Angeles, 1981. /8/D.Talbot Rice, Byzantine Glazed Pottery, Oxford, 1930. //, Bull, du Musee National de Varna, vol.X.(xxv) (197*0 i!55. DETERMINATION OF TRICE ELEMENTS IN SOIL Maria S&l&gean, Ana Pantelica Institute for Physics and nuclear Engineering Bucharest MG-6, Romania Abstract! Concentration of 32 elements in reference material SOIL-7 is determined INTRODUCTION The work described in this paper was the subject of an intercomparison organised by IAEA's Analitycal Quality Control Service on the determination of tract elements in soil materials (Soil-7 collected near Ibensee in Upper Austria) la order to provide a reference material for multielement analyses and also to verify the performance of different analysis methods of the par- ticipating laboratories. The composition of soil is of interest for the specialists in various fields of research as geology, biology, nutrition and environmental pollution. A number of 56 laboratories from 25 countries using different methods of ana- lysis sent their results at this interoomparison. Activation analysis was the most frequent method used (38 % of all determinations). EXPERIMENTAL By using the instrumental neutron aotivation analysis method the concen- tration of 32 elements has been determined in our laboratory. She concentration of Ba, Oa, Oe, Oo, Os, Cr, Iu( Fe, Hf, La, Lu, Nd, Rb, Sb, So, Sm, Sr, Ta, Tb, Th, U, Ib, Zn, Zr have been determined after 50 hours irradiation time in a thermal neutron flux of l.lxiolln/cne.s. The samples («J 150 mg in weight) and Soil-5, SL-1, GSP-1 as standards have been measured 2-5 hours after 10 a- 30 days. In a pneumatlo tube with a lO^n/onF.s. flux the samples and W-l stan- dard material have been Irradiated for 1-3 minutes. After 6 min.- 24 hours deoay time the samples were measured for 100 - 1800 s. The concentration of Al, Dy, lu, X, Hg, Un, Ba, Sm. Ti, Y was in this way determined. In both types of irradiation the concentration values are the arithmetic average of the va- lues for 4 independent determinations. A multichannel analyser connected to a 65 om? Go (Li) detector with 2 keV resolution was used* RESULTS ADD DISCUSSION The results for the concentration of the elements thus determined are presented in table 1. These values are classified by the IAIA (column 5) as recommended values with satisfactory (A) or acceptable (B) degree of confidence and information values - non-oertified (0). lor the major elements Al, Oa, Fe, llg, E, Na and Ti their values pass all the test criteria of class A but their confidence Intervals are larger than those usually required for major components of reference materials. These va- lues oan not be certified but may be used as reference values In the oases in which these too large confidence intervals do not cause problems in future analytical works. These elements are denoted by A* . Our results shown in table 1 are in a good enough agreement with the re- sults presented by IAEA exoept for U and Sr concentration. In this case our value was rejected by statistioal test. For Oa and Zn our values of concentra- tion have been taken into aooount in the estimation of the results although these values are outside of confidence intervals. TABLE 1 Element <»•«••«•*"•• Confidence intervals Our results Al(%) 4.7 4.4 - 5.1 4.2 ± 0.1 A* Ba 159 131 - 196 195 + 16 0 0a(*) 16.3 15.7 - 17.4 11.6 + 0.2 A* Oe 61 50 -63 53 + 1 B Oo 8.9 6.4 - 10.1 9*2 + 0.2 A Or 60 49 - 74 64 + 1 B 191 0 1 2 3 4 Os 5.4 4.9 - 6.4 5.2 + 0.2 B »y 3.9 3.2 - 5.3 3.3 ± 0.2 B 1.0 0.9 - 1.3 1.05 + 0.13 B *«(*> 2.57 2.52 - 2.63 2.56 + 0.05 A* Hf 5.1 4.8 - 5.5 4.7 + 0.2 A K(J6) 1.21 1.13 - 1.27 1.28 + 0.05 A* La 28.0 27.0 - 29.0 28.3 + 0.4 B La 0.3 0.1 - 0.4 0.34 + 0.01 C Mg(%) 1.13 1.10 - 1.18 1.11 + 0.14 A* Ufa 631 604 - 650 605 + 16 A Na(56) 0.24 0.23 - 0.25 0.223 + 0.004 A* Hd 30 22 - 34 31 + 2 B Kb 51 47 - 56 49+4 A Sb 1.7 1.4 - 1.8 1.77 + 0.10 B So 8.3 6.9 - 9.0 8.4 + 0.1 B SB 5.1 4.8 - 5.5 5.5 + 0.2 B Sr 108 103 - 114 161 • 17 B Ta 0.8 0.6 - 1.0 0.58 + 0.13 B Tb 0.6 0.5 -0.9 0.85 + 0.13 B Th 8,2 6.5 -8.7 8.03 • 0,10 B Ti(56) 0.3 0.26 - 0.37 0.26 + 0.03 A* U 2.6 2.2 - 3.3 0.91 + 0.12 A V 66 59 -73 54 + 5 A Xb 2.4 1.9 -2.6 2.4 + 0.1 B Z& 104 101 - 113 161 ± 10 A Zr 185 180 . 201 185 + 26 A 192 &G860C/&1 INVESTIGATION OF THE CONNECTION BETWEEN SURFACE WATER AND UNDER- GROUND WATER PROM MINE GAOOVA-IERII, USING AGTIVABIiE TRACERS Lucretia Dinescu, Victoria Domocos, St. Craciun Institute for Physics and Nuclear Engineering Bucharest MG-5, Romania Abstracts The paper emphasizes the advantage of using the activa- ble tracers when studying the mining hydrogeology. Two tracers where simulta- neously used! indium in the form of In-EDTA complex and the radioisotope 82-Br. The determination of indium was carried out by passing the water samples through the ion exchangercolum/i to retain the other disturbing elements (such asi Mn, 01, Na, K, etc*)* Then indium was copreclpitatied with bismuth hydroxi- de and was determined by neutron activation analyses. The connection between surface waters and underground Cacova-Ieril mine water was proved. Concomiten- tly, valuable data regarding the velocity and the circulation way could be ob- tained. INTRODUCTION The radioactive tracers techniques is succesfully used in hydrogeological studies for many years* In the past years, due to limits imposed by sanitary norms, it was necessary to use lower and lower activities. Since in the most cases of hydrologioal tracer applications, a high dilution occurs,the radio- isotope concentration in the measuring point could be under the detection li- mit. Problems of radiation protection do not rise by the use of inactive tra- cers. The most reliable tracer for this purpose is Indium, as In-EDTA complex, wich can be detected in very low concentrations, by NAA based on gamna-spec- trommetry. Two tracersi inactive indium and radioisotope 82-3r were simultaneously used for hydrogeological studies performed in Oacova-Ierii tested area. EXPERIMENTAL The water flow rate looses on the river Oacova and Ier^ii were determined by classical methods* The In-EDTA and 82-Br were used to prove the connection between surface and infiltrating mine water. Quantities of 750 ml water were collected at different time intervals, at four mine deph levels. Eaoh water sample was passed through the ion exchanger column, to retain the other disturbing ions (Fe, tin, Cl, Na, K, etc.). The In-EDTA complex was distroyed by adding HgSO*. Indium was coprecipitated with Bi(OH)g* The precipitate was collected on molecular filters wioh were put into the plastic bags-heat sealed. Bach bag was wrapped in aluminium foil. 8-10 samples along with standard wera irradia- ted simultaneously at a lO1?n/cm2.s. flux, in the WR-S reaotor and measured immediatly after irradiation. The standards were prepared in the same way as the samples* Irradiation time was 20 min. and measuring time 200 a. Nuclear data for indium are given in table 1* TABLE 1 Nuclear data for indium IJ! Isotope leotopio l/2 Photopeak xsecopfj abundance (%) barn Product min. used (keV) U 116> 5in 95.7 155 ln 5* 417.0 Measurements were performed with a Ge(Li) detector and ND-6620 acquisi- tion and processing system. The deaintegration correction was taken into ac- count for concentration calculation* The 82-Br determination was carried out by "in situ" measurements with a sointillation probe* RESULTS AND DISCUSSION Four experiments have been performed in tested area Oaoova-Ierii. For three marking points, situated on the small riverst Vadului, Oacova and Ierfcii, the connection between surface water and underground mine water was proved* In the fourth experiment, the decanting pond was marked with In-BDTA. 193 The In tracer did not appear in mine infiltrating, water, so it was proved that no connection exists between surface and underground water in this point, The results obtained were used to establish the transit times. REFERENCES /I/ H. Behrens, H. Moser, S. Wildner, J. Radioanal. Ohem., 38 (1977) 491 /2/ S.P. Stanescu, E. Gagpar, S. Spiridon, O.M. Fareaspiu, R. Catilina, Preprint ICEFIZ, NP 24 - Decembrie 1982 /5/ So Ga§par, O.M. Farcagiu, S.P. Stanescu, S. Spiridon, Froc. First Bymp. on Theoretical and Applied Kara to logy, Bucharest 22-24 April 1983. FAST NEUTRON ACTIVATION ANALYSIS OF SHORT-LIVED NUCLIDES IN SOME GEOLOGICAL SAMPLES S.M.Al-Joboti, et al. Fast neutron activation analysis technique was applied for the determination of major, minor and trace elements (such as Si, Fe, Ti, Al, Zr, Au and U) in geological samples. The samples and standards were irtadiated with a monoenerqetic neutron flux of 109 n.cm~2-S produced by KAMAN type neutron generator. The pneumatic facility was used to transfer the sample and standard between the irradiation and counting stations. The standard was prepared from flint clay obtained from NBS. The gamma-ray activities from samples and standards were counted using a 30 cm3 Ge(Li) detector (FWHM) = 2.9 keV at 1.33 MeV) coupled to on-line computer facility. 195 AUTHOR INDEX Alekaandrov, S.: 60 Pareasiu, 0. M.: 177 Alicu, 0.: 183 Fiat, T.: 183 Al-Jobori, S. II.: 194 Franko, M.: 35 Apostol, E.: 44 Prontasieva, M. V.: 177 Apostoleaou, S.: 5, 29 Apostolov, D.: 3, 63, 93, 129, 152 Galatanu, V.: 47, 50 Arpadjan, S.: 60 Galis, V.: 74 Avrigeanu, M.: 69 Caspar, E.: 177 Avrigeanu, V.: 69 Geisler, H.: 141 Gharib, A.: 137 Bakyrdschiev, P.: 92 Gosar, A.: 35 Besliu, C: 186 Grigorov, T.: 63, 66, 93, 129 Blaga, N.: 47 Grimanis, A.: 8, 129 Boros, 0.: 183 Grozev, G.: 71 Bozanic, M.: 83 Bradeanu, A.: 47 Haidoutov, I.: 157 Byrne, A. R.: 35, 55 Hoste, J.: 19 Calcev, G.: 74 Iordanov, I.: 180 Catena, D.: 47, 50 Iovtchev, M.: 63, 92, 93, 129 Choulia, N. H.: 87 Ivanov, E.: 37 Cojooaru, V.: 57, 186 Ivascu, 11.: 69, 186 Constantinescu, B.: 37 Cosma, C: 183 Janakiev, K.: 66 Cracium, S.: 192 Jovanovic, S.: 19, 165 Daieva, L.: 157 Kanias, G. D.: 07, 129 Damyanov, B.: 71 Karamanova, J.: 71 Dan, C.: 44 Kemileva, Z«: 93 Dan, R.: 74 Kinova, L.: 79, 85, 93, 108, 129 Daraban, L,: 183 Kjoetarova, 0.: 121, 134 Debert, C.j 74 Kosta, L.: 35, 55 De Bruin, M.: 85, 95 Koatic, K.: 90 De Corte, P.: 19 Kosutic, K.: 118 Demiralp, R.: 124 Kukoe, A.: 125 DermelJ, M.t 35, 55 Kuleff, I.: 25, 40, 60, 92, 128, Dimaerian, D.: 186 162, 189 Dimitrov, D.: 52 Dineseu, L.: 160, 175, 192 Lulic, S.: 110, 115, 118 Djingova, R.: 60, 128, 162, 189 Djulgerova, E.: 92 Marichkova, L.: 121, 134 Domnisan, M.: 74 Mocanu, N.: 74 Domocos, V.: 192 UoenB, L.: 19 Dragnev, T.: 71 Morariu, V.: 183 Draskovic, R, J.: 83, 90, 125 Motiu, A.: 149 196 AUTHOR INDEX Naataae, It.: 74 Spiridon, G.: 113 Nazarov, V. 11.: 177 Spiridon, S.: 57, 113, 174, 177 Nikolov, P.: 129 Staneacu, S.P.: 177 Stankovic, S.: 90 Pantelic, M.: 125 Stefanov, G.: 40 Panteliea, A.: 29, 44, 113, 149, Stegnar, P.: 35, 132 171, 174, 190 Stojanov, A.: 129 Papadopoulos, N. N.: 154 Papadopoulou, C: 129 Taekaev, E.: 32, 60, 65, 108, Pascovici, G.: 37 129, 152 Pavioic, J.: 132 Tchounev, D.: 180 Penev, I.: 85, 108, 129, 162 Teodosiu, G.: 74 Petrov, J. G.: 25 Tepelea, V.: 74 Plamada, C: 160, 175 Timus, D.: 47, 50 Plostinaru, D.: 37 Tomov, L.: 66 Popa-Nemoiu, A.: 37 Tusek-Znidaric, M.: 132 Popesou, 0.: 47 Popovioi, D.: 186 Vassilaki-Grimani, M.: 129 Purice, E.: 74 Vertacnik, A.: 115 Vukotio, P.: 19, 165 Salagean, ».: 29, 44, 113, 149, Vutchkov, H.: 66 171, 174, 190 Schelhorn, H.s 152 Zafiropouloa, D.: 129 Sevimli, H.: 61 Zejnilovie, R.: 19 Stmonlta, A.: 19 ZnamirovBChi, V.: 149, 183 Skreblin, U.: 132 Zotschev, S.: 40 Smodis, B.: 55 Zvonaric, T.: 132Borman, E.Keuert, w.Soobel, Handbook on Huolear Aotlvatlon oroas-seotions, IAIA Ho.156, IAIA Vienna (1974) /3/ M.Ivaeou, M.Avrigeanu, V.Avrigeanu. preprint IP-28-1983, Buoharest, I •?•£?!• (1983) /4/ LSadBistolios, O.Paptdopoulu, J. Badloamal.Ohem.72(1982)597 /5/ J.P.Delaroohe, Oh.Lagrange, J.Salvy, Huolaar Theory in leutron Vuolear Data Iraluatlon (IA1A-190), Vienna IAIA, vol.1 (1976) pp.251 /6/ Oh.Lagrange, Neutron Data of Structural Materials for Past Beaotors, K.H.Booknott (Id.),Pergamon Praaa,Oxford (1979) PP.756 /?/ O.H.Johnaon, A.Galonsky, B.L.Eermell. Phys.Bev« 0 20 (1979) 2052 /8/ Oh.Lagxange, Phya. Bev. 0 22 (1980) 896 /9/ R.GToIarkaon, W.B.Ooker, O.P.ltoore, Phys.Bev. 0 2 (1970) 1097 /10/ r.S.Park, B.D.Jones, D.I.Bainum, Phys.Bev. 0 4 (1971) 778 /ll/ D.G.Gaxdner, Preprint UOBL - 87438. Llvermoora (1982) /12/ A.V.Ignatyuk, G.H.Bairenkin, A.8.Tishin, Tad.Tis. 21(1975) 485 /13/ W.D.myera, W.S.Swiateokl, Ark.Pyeik. 36 (1967) 593 AV H.Blaan, H.K.Vonaoh, Phys.Bev. 0 28 (1983) 1475 /15/ O.T.PU, Huol.8oi.Ing. 86 (1984) 344.