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International Conference ACTIVATION ANALYSIS

October 15—19,1990 Beijing, China

ABSTRACTS

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Division of Activation Analysis and Radioanalysis, China 1990 Beijing International Conference ACTIVATION ANALYSIS AND ITS APPLICATIONS (ICAAA) October 15—19,1990 Beijing, China

ABSTRACTS

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Division of Activation Analysis and Radioanalysis, China 1990 Beijing Organized by Division of Activation Analysis and Radioanalysis Sponsored by National Natural Science Foundation of China (NSFC) Chinese Nuclear Society (CNS) Chinese Chemical Society (CCS) Chinese Academy of Sciences (CAS) Nuclear Physics Society, CNS (NPSC) Nuclear and Radiochemical Society, CNS (NRSC) Beijing Nuclear Society (BNS) Chinese Association for Science and Technology (CAST) International Centre for Theoretical Physics (ICTP)

International Advisory Committee Chatt,A (Halifax) Das.H.A. (Petten) Iyengar,V. (Gaithersburg) Lennihan,J. (Glasgow) Liu,Y. F. (Beijing) Moauro,A. (Rome) Ni'ese,S. (Dresden) Park.K.S. (Seoul) Sabbioni,E. (Ispra) Suzuki,N. (Sendai) Yakovlev,Y.V. (Moscow) Yeh.S.J. (Hsinchu)

National Committee Chai Chifang (Beijing)—Chairman Feng Xichang (Beijing, Publication) Li Shounan (Beijing) Liu Desao (Beijing) Sun Jingxin (Beijing) Tian Weizhi (Beijing, Publication) Tong Chunhan (Chendu) Wang Yongxian (Shanghai) Wu Zhihua (Shanghai) Xiao Lun (Beijing) .SK2s«. Xu Honggui (Beijing) Zhang Zhiyao (Beijing) Zhao Pengji (Chendu) Zhong Honghai (Guangzhou) Zhou Ruiying (Beijing) Zhou Yunlu (Beijing) Organizing Committee Chai Chifang—chairman Ju Kefei Qiu Xibai Sun Jingxin Tian Weizhi Wang Yongxian Zhang Zhiyao CONTENTS

AL-Joboori, S.M., AL-Bedri, M.B.H. and Hassan, H.A.A. TRACE AND TOXIC ELEMENT DETERMINATION IN DRINKING WATER OF IRAQ BY NEUTRON ACTIVATION ANALYSIS ICAAA-001 1

Aarnio, Pertti, Hakulinen, Timo and Routti, Jorma EXPERT SYSTEMS FOR NUCLIDE IDENTIFICATION AND INTERPRETATION OF GAMMA SPECTRUM ANALYSIS ICAAA-002 4

Adams, Bruce, Gihwala, Dherendra, Peisach, Max and Dent, D. THE DETERMINATION OF TRACE AND MINOR ELEMENTS IN BREAST CANCER TISSUE

ICAAA-003 6

Alexandrova, G.I., Shmanenkova, G.I. and Pugatcheva, O.P. CHARGED PARTICLES ACTIVATION IN ANALYSIS OF PURE MATERIALS ICAAA-004 8

Andreev, A.V., Varich, O.M. and Makarov S.A. PRECISE 14 MeV NEUTRON ACTIVATION ANALYSIS ICAAA-005 9

Anikiev, V.V., Prasad, S.K., Polyanova, T.Yu.and Kolesov, G.M. STUDIES OF DISTRIBUTION OF CHEMICAL ELEMENTS IN SUSPENDED MATTER AND BOTTOM DEPOSITS OF CONTINENTAL SHELF OF EASTERN CHINA SEA USING NEUTRON ACTIVATION ANALYSIS ICAAA-006 11

Asubiojo, O.I., Obioh, I.B., Oluyemi, E.A., Oluwole, A.F. and Spyrou, N.M. ELEMENTAL CHARACTERISATION OF AIRBORNE PARTICULATES AT TWO NIGERIA LOCATIONS DURING THE HARMATTAN SEASON ICAAA-007 13

Bao Weidong, Zhou Manfang and Yuan Genie DETERMINATION OF 12 RARE-EARTH ELEMENTS IN HiGH-PURE Sc203 BY PRETREATMENT NEUTRON ACTIVATION ANALYSIS ICAAA-008 . 16

Berzina, I.G., Gusev, E.B., Lukin, V.I. and Rilnikov, V.S. STUDY OF BRAZED AND WELDED JOINTS BY METHODS OF RADIOGRAPHIC ACTIVATION ANALYSIS ICAAA-009 l8

I Capannesi, G., Sedda, A.F. and Cecchi, A. OAK LEAVES FEASIBILITY AS GASEOUS POLLUTION MONITOR ICAAA-010 20

Capannesi, G. Renzi, L., Sedda, F. and Jin, Li-Yun STUDY OF TRACE ELEMENT IN HAIR SAMPLES FROM TWO CHILDREN AT DIFFERENT DATE BY USING INAA ICAAA-011 22

Chai Chifang, Ma Shulan, Zhao Zhenhua, Zhao Huilan, Mao Xueying, Ma Jianguo and Zhou Yaoqi DETERMINATION OF REE ABUNDANCES IN MINUTE BIOGENIC APATITE BY NAA AND ITS GEOCHEMICAL SIGNIFICANCE ICAAA-12 M

Chatt, A. and Jayawickreme, C.K. STUDIES ON SPECIATION OF TRACE ELEMENTS IN BIOLOGICAL MICROMOLECULES ICAAA-013 * 26

Chen Yinliang and Wang Xiaoling NEUTRON ACTIVATION ANALYSIS OF RHENIUM IN ROCKS ICAAA-014 28

Cheng Yuandi, Wang Xuepeng, Qian Yine, Zhang Yuanxun and Tan Mingguang PREPARATION AND CERTIFICATION OF THE HUMAN HAIR REFERENCE MATERIAL ICAAA-015 29

Ciftcu, Em. and Popa-Nemoiu, Al. UNCERTAINTIES IN THE CHARGED-PARTICLE ACTIVATION ANALYSIS AT CYCLOTRON ICAAA-016 31

Constantinescu, B.,.Pascovici, G. and Plostinaru, D. LIGHT ELEMENTS DETERMINATION USING ACTIVATION METHOD AT THE INPE CYCLOTRON ICAAA-017 33

De Nadai Fernandes, Elisabete A., Ferraz, Epaminondas S.B., Martinelli, Luiz A. and de Oliveira, Helder AMAZON BASIN: TRACE ELEMENTS IN VARZEA SEDIMENTS ICAAA-018 35

I Deng Hongmin and Li Jianming STUDY OF BORON IN LEGUME FORRAGES USING SOLID STATE NUCLEAR TRACK DETECTOR ICAAA-019 37

Dighe, P.M., Pansare, G.R. and Bhoraskar, V.N. MEASUREMENT OF FILM THICKNESS BY 14 MeV NEUTRON ACTIVATION ANALYSIS ICAAA-020 39

Dighe, P.M., Panasare, G.R., Kulkarni, S.G. and Bhoraskar, V.N. USE OF 14 MeV NEUTRON IN ANALYSIS OF EXPLOSIVE CLASS MATERIALS ICAAA-021 41

Dim, LA, Adetunji, J. and Okujeni, CD. INAA OF VEINED PYROCLASTIC ROCKS FROM ABAKALIKI, LOWER BENUE TROUGH NIGERIA ICAAA-022 43

Ding Zuguo, Chai Chifang, Fu Jiamo and Sheng Guoying INVESTIGATION ON TRACE ELEMENTS IN THE CRUDE OILS AND ORGANIC MATERIALS EXTRACTED FROM SOURCE ROCKS FROM CHINA WITH INAA ICAAA-023 44

El-Amri, F.A. and El-Saltani, H.E. DETERMINATION OF TRACE ELEMENTS IN NORMAL AND DIABETIC WHOLE BLOOD BY NEUTRON ACTIVATION ANALYSIS ICAAA-024 46

Elteren, J.T. van and Das, H.A. SPECIATION OF ARSENIC IN WATER SAMPLES ICAAA-025 48

Englert, Peter A.J., Castaneda, Carlos M., Sanii, Behzad, Drake, Darrel M., Reedy, Robert C and Young, John C. PLANETARY GAMMA-RAY SPECTROSCOPY: METHODICAL IMPROVEMENTS THROUGH NEUTRON INELASTIC SCATTERING CROSS SECTIONS BETWEEN 20 AND 70 MeV ICAAA-026 51

I Esposito, M., Collecchi, P., Oddone, M., Martines, H., Aste, H., Merlo, F., Meloni, S., Caramella-Crespi, V. and Genova, M. PLASMA AND TISSUE LEVELS OF SOME LANTHANIDE ELEMENTS IN THE HUMAN COLORECTAL LESIONS ICAAA-027 53

Fang Hong, Feng Xizhang and Chai Chifang A STUDY OF THE NINQIANG CARBONACEOUS CHONDRITE MATRIX BY INAA ICAAA-028 55

Feng Songlin, Zhong Ming, Ren Minqin and Liu Nianqin PROGRESS IN MEASURING THE IMPURITY CONTENTS IN A BaF2 CRYSTAL USING THE PIXE ANALYSIS ICAAA-029 57

Flitsiyan, E.S. USE THE METHOD OF ACTIVATION RADIOGRAPHY FOR GEOLOGICAL AND GEOCHEMICAL INVESTIGATION ICAAA-030 59

Genova, N. PROVENANCE STUDIES OF ANCIENT ETRUSCAN MARBLES BY NEUTRON ACTIVATION ANALYSIS AND DATA REDUCTION ICAAA-031 61

Ghafourian, H., Ali, Sameh A. and Ache, H.J, SEPARATION OF TECHNETIUM FROM DISSOLVED RESIDUES OF IRRADIATED NUCLEAR FUEL ICAAA-032 63

Gihwala, Dherendra, Lackay, Lotter Geoffrey and Peisach, Max MEASUREMENT OF PROTON INDUCED PROMPT LOW ENERGY PHOTONS BY RESOLUTION SPECTROMETRY: THE ANALYSIS OF NOBLE METALS LANTHANIDES ICAAA-033 64

Hien, P.Z., Mai, T.K., Quang T.X., Loc, N.V. and Thuy T.N. DETERMINATION OF Ko-FACTORS OF SHORT-LIVED NUCLIDES (Tl/2 < 1 MIN, ) BY THERMAL NEUTRON ACTIVATION TECHNIQUE ICAAA-034 66

Holzbecher, J. and Ryan, D.E. ANALYSIS OF IRON METEORITES BY INSTRUMENTAL NEUTRON ACTIVATION WITH A SLOWPOKE REACTOR ICAAA-035 68

W Ha, P. MULTIELEMENT ANALYSES OF BLOOD AND SERUM SAMPLES OF DIABETIC PERSONS BY INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS ICAAA-036 70

Izak-Biran, T., Mantel, M., Lavy, N., Even, 0. and Shenberg, C. DETERMINATION OF SELENIUM AND OTHER ELEMENTS IN HUMAN COLON TISSUE BY INAA; COMPARISON WITH RESULTS OBTAINED BY XRF METHOD ICAAA-037 72

Jin Li-Yun, Li Yun and Yang Ming RNAA OF ULTRA-TRACE Ir IN PRECAMBRIAN-CAMBRIAN BORDER SAMPLE BY THIOUREA-TYPE CHELATE RESIN SEPARATION ICAAA-038 n

Kanias, George D. NUTRIENT AND OTHER TRACE ELEMENTS IN INSTANT SOUPS ICAAA-039 76

Karandashev, V.K. and Grazhulene, S.S. APPLICATION OF EXTRACTION CHROMATOGRAPHY IN NEUTRON ACTIVATION ANALYSIS ICAAA-040 78

Karpov, Yu.A., Kudinov, B.S. and Murashov, M.V. GAS EXTRACTION IN ACTIVATION ANALYSIS ICAAA-041 8°

Kennedy, G. and Hobeika, S. PSEUDOCYCLIC ACTIVATION OF GEOLOGICAL MATERIAL ICAAA-042 82

Kennedy, G. and Bergeron, S. TREE RINGS AS MONITORS OF HEAVY METAL AIR POLLUTION HISTORIES ICAAA-043 84

Khrbish, Y.S. and Spyrou, N.M. PROMPT GAMMA-RAY NEUTRON ACTIVATION ANALYSIS BY THE ABSOLUTE METHOD ICAAA-044 86

v Knaus, Ronald M. INSTRUMENTAL NEUTRON ACTIVATION METHODS TO MEASURE SHORT- TERM ACCREATION AND EROSION IN WETLANDS WITH RARE EARTH SOIL HORIZON MARKERS ICAAA-045 88

Knorr, J., Schiekel, M., Franke, W. and Focke, F. PROTEIN DETERMINATION IN SINGLE GRAINS BY INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS ICAAA-046 90

Kolesov, G.M. NEUTRON ACTIVATION ANALYSIS IN SOLVING UNIQUE GEOCHEMICAL AND COSMOCHEMICAL PROBLEMS ICAAA-047 92

Kolesov, G.M., Barsukova, L.D., Miklishansky, A.Z., Nazarov, M.A. and Sapozhnikov, D.Yu NEUTRON ACTIVATION DETERMINATION OF IRIDIUM AND SOME NOBLE METALS IN ROCKS, IMPACTITES AND OTHER GEOCHEMICAL SAMPLES ICAAA-048 94

Kolesov, G:M., Kudryashova, A.F., Mashtalka, A., Tarasov, L.S., Frana, Ya. and Shubina, N.A. SPECIAL FEATURES OF COMPOSITION OF LUNAR BASALTIC ROCKS BY NEUTRON ACTIVATION ANALYSIS ICAAA-049 96

Kolotov, V.P., Atrashkevich, Vajda I., Nagy, P., Brech, F., Kadar, A. and Vasarhely, F. ASPRO : A SOFTWARE PACKAGE FOR AUTOMATIC PROCESSING OF GAMMA RAY SPECTRA ICAAA-050 97

Kolotov, V.P., Mua, Le Tat and Nekrasova, N.N. SIMPLE RADIOCHEMICAL PROCRDURE FOR DETERMINATION OF SOME ESSENTIAL AND TOXIC ELEMENTS IN BIOLOGICAL SAMPLES BY NAA ICAAA-051 "

Kong Ping, Chai Chifang, Mao Xueying, Ma Jianguo c-nd Ma Shulan STUDY OF CHEMICAL SPECIES OF ANOMALOUS IRIDIUM IN CRETACEOUS TERTIARY (K-T) BOUNDARY CLAY WITH RNAA AND CHEMICAL STEPWISE DISSOLUTION PROCEDURE .ICAAA-052 101

VI Lackay, L.G., Gihwala, D. and Peisach, M. MEASUREMENT OF PROTON-INDUCED PROMPT LOW ENERGY PHOTONS BY HIGH RESOLUTION SPECTROMETRY: THE ANALYSIS OF NOBLE METALS ICAAA-053 103

Levine, Louis D. MICROPROVENANCE STUDIES OF ARCHAEOLOGICAL CERAMICS: A CASE STUDY FROM THE KANGAVAR AND MAHIDASHT VALLEYS, CENTRAL WESTERN IRAN ICAAA-054 105

Li Guodong and Tong Chunhan APPLICATION OF NAA IN ANALYSIS OF SEDIMENTARY ENVIRONMENTS IN SHALLOW SEA ICAAA-055 107

Li Yinming, Ding Yuzheng and Sun Xiaozhong SOME ASPECTS OF RADIOANALYTICAL CHEMISTRY OF 196, 198Au, 192lr, 186Re, AND 96Tc ICAAA-056 109

Lin Xilei and Heydorn, K. EFFECT OF CASCADE COINCIDENCES ON THE EFFICIENCY CALIBRATION OF A GAMMA-X DETECTOR ICAAA-057 11°

Lin, Xilei, Speziali, M. and Orvini, E. A PREIRRADIATION SEPARATION PROCEDURE FOR GALLIUM DETERMINATION IN BIOLOGICAL AND ENVIRONMENTAL MATERIALS BY NEUTRON ACTIVATION ANALYSIS ICAAA-058 112

Liu NianQing, Zhang, Xiaofeng, Feng Songlin and Zhong Ming THE METABOLISM OF TITANIUM AND OTHER ELEMENTS IN WISTER RAT ICAAA-059 H-1

Liu Yuren and Seymour, R.S. AN ON-LINE THERMAL NEUTRON PROMPT GAMMA MEASUREMENT SYSTEM FOR BULK DETERMINATION OF AL AND FE IN METAL ORES ICAAA-060 116

Lo Jem-Mau, Lin Yeu-Ping and Cheng Chia-Cheng SOLVENT EXTRACTION OF DITHIOCARBAMATES COMPLEXES AND BACKEXTRACTION WITH PALLADIUM(II) FOR DETERMINATION OF TRACE METALS IN SEAWATER BY NEUTRON ACTIVATION ANALYSIS ICAAA-061 118

vn Loureiro, A.L.M., Vasconcellos, M.B.A. and Pereira, E.B. TRACE ELEMENT DETERMINATION IN AEROSOLS FROM THE ANTARCTIC PENINSULA BY NEUTRON ACTIVATION ANALYSIS ICAAA-062 121

Lu HuiJuan and Zhou YunLu DETERMINATION OF RARE-EARTH ELEMENTS IN HIGH-PURE YTTRIUM OXIDE BY NEUTRON ACTIVATION ANALYSIS ICAAA-063 123

Lu Zhaoda, Li Yinming, Qian Ruisheng, Chen Da and Chang Yongfu THE SYSTEMATIC SEPARATION AND RADIOCHEMICAL DETERMINATION METHOD FOR NEUTRON ACTIVATED NUCLIDES AND SOME ACTINIDES ICAAA-064 125

Ma Jianguo and Sun Jianguo AN EXPERT SYSTEM FOR NEUTRON ACTIVATION ANALYSIS ICAAA-065 126

Mao Zhixiang, Yan Peilan, Huang Jianwei, Dai Xiankai, Chai Chifang, Qian Qingfang and Ma Jianguo A STUDY OF THE SEDIMENT MOVEMENT WITH THE METHOD OF NEUTRON ACTIVATION ANALYSIS ICAAA-066 128

Moauro, A. and Carconi, P.L. NEUTRON IRRADIATION OF LiAL02 AS CANDIDATE CERAMIC BREEDER MATERIAL OF THE FUSION REACTORS;r-SPECTROMETRY OF THE ACTI­ VATION NUCLIDES & EVALUATION OF THE TRITIUM PRODUCED BY(n, r) ICAAA-067 130

Moauro, A. and Carconi, P.L. AN EUROPEAN INTERCOMPARISON OF VEGETAL STANDARD REFERENCE MATERIALS, BASED ON INAA AND SOME NON NUCLEAR SPECTRO- CHEMICAL TECHNIQUES ICAAA-068 132

Ni Bang-Fa and Tian Wei-Zhi NAA OF IAEA LAKE SEDIMENT RM SL-3 FOR 45 ELEMENTS ICAAA-069 133

Ni Bang-Fa, Wang Pingsheng, Luo Yingjun and Yu Shouyan STUDY OF THE BIOAVAILABILITY OF ZINC USING ACTIVABLE ISOTOPE TRACER 70-ZN BY NEUTRON ACTIVATION ANALYSIS ICAAA-070 I35

vm Niedergesaess, R., Schnier, C. and Pepelnik, R. ANALYSIS OF FERTILIZER PHOSPHATES USING REACTOR NEUTRONS AND 14 MeV NEUTRONS ICAAA-071 137

Niese, S., Krogner, K., Gleisberg, B., Werner, CD., Pfeiffer, L. and Kramer, W. INVESTIGATION OF MANTLE-DERIVED MAGMATITLES BY NEUTRON ACTIVATION ANALYSIS ICAAA-072 138

Niese, S. and Helbig, W. LOW RADIOACTIVITY MEASUREMENT OF ACTIVATED NUCLIDES IN AN UNDERGROUND LABORATORY ICAAA-073 14°

Nikolaenko, O.K., Mirotin, I.V. and Goldshtein, M.M. NEUTRON ACTIVATION DETERMINATION OF OXYGEN COEFFICIENT FOR HIGH-TEMPERATURE SUPERCONDUCTING MATERIALS ICAAA-074 U2

Nodar, Shonia, Liguri, Mosulishvili and Nana, Kharabadze ON THE POSSIBILITY OF EXPERIMENTAL DETERMINATION OF MICROELEMENT BIOVARIABIUTY IN BIOLOGICAL SYSTEMS ICAAA-075 lu

Nonie, S.E., Randle K. and Blackband, A.G. DEVELOPMENT OF A COMPUTER-BASED SYSTEM FOR FAST NEUTRON CYCLIC ACTIVATION ANALYSIS ICAAA-076 146

Nonie, S.E. and Randle, K. MULTI-ELEMENT DETERMINATIONS OF ROCK SAMPLES USING FAST NEUTRON CYCLIC ACTIVATION ANALYSIS ICAAA-077 1«

Olivier, C. and Morland, H.J. THE ELIMINATION OF MATRIX EFFECTS IN THE DETERMINATION OF FLUORINE BY PROTON-INDUCED PROMPT GAMMA SPECTROMETRY ICAAA-078 150

Pantelica, Ana, Salagean, Maria and Nicolae, Marieta IMPURITY CONTENT DETERMINATION !N HIGH PURITY CERAMIC POWDERS BY NEUTRON ACTIVATION METHOD ICAAA-079 152

K Papadopoulos, Neophytos l\l. and Synetos, Sotiris RECENT DEVELOPMENTS IN SHORT-LIVED NUCLIDE ACTIVATION ANALYSIS AND ANALYTICAL EFFICIENCY ICAAA-080 m

Patil, S. F., Rajurkar, N.S.(nee Adhyapak) and KANADE, K.G. THERMAL NEUTRON ACTIVATION ANALYSIS OF MINERAL NUTRIENTS IN DIFFERENT VARIETIES OF RICE IN INDIA ICAAA-081 156

Peisach, Max, Pineda, Carlos A., Jacobson, Leon and Loubser, Jan H.N. NUCLEAR ANALYTICAL STUDY OF ROCK PAINTINGS ICAAA-082 158

Peisach, Max, Pineda, Carlos A., Jacobson, Leon and Loubser, Jan H.N. ANALYTICAL STUDY OF NAMIBIAN POTTERY FROM SOUTPANSBERG ICAAA-083 160

Peisach, Max and pineda, C.A. DETERMINATION OF ALUMINIUM AND SILICON IN ZEOLITES BY PIXE ICAAA-084 162

Peng Lixin and Tian Weizhi INAA OF IAEA-155 WHEY POWDER FOR PHOSPHORUS AND OTHER 24 ELEMENTS ICAAA-085 m

Pillay, E.A. and Peisach, Max A SENSITIVE BORON PROBE USING THE REACTION 10B(3He, n)12N ICAAA-086 166

Pineda, Carlos A. and Peisach, Max PROMPT ANALYSIS OF RARE EARTHS BY HIGH ENERGY-INDUCED (p, x) REACTION ICAAA-087 168

Preoteasa, E.A., Salagean, M., Pantelica, A., Berceanu, St., Plostinaru, D., Constantinescu, B., Lungu, V. and Vilcu, Al. INAA AND PIXESTUDY ON THE COMPLEX MODIFICATIONS OF HUMAN BLOOD SERUM MINERAL COMPOSITION IN SEVERAL HEMOPATHIES ICAAA-088 I70

X Qian Qinfang, Wu Suiqin, Tian Jibin and Chen Shiqing MULTI-ELEMENT DETERMINATION OF SOIL SOLUTION BY INAA ICAAA-089 172

Qian Xingzhen, Li Xiuxia A NEUTRON ACTIVATION ANALYSIS STUDY OF THE BACKGROUND VALUES AND STATES OF ELEMENTS IN NATURAL WATER ICAAA-090 174

Rajurkar, N.S. (nee Adhyapak), Patil, S.F., and Ballari, P.R. ELEMENTAL ANALYSIS OF AGRICULTURAL SOILS IN MAHARASHTRA (INDIA) BY INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS ICAAA-091 176

Rao, R.R., McDowell, L.S., Jayawickreme, C.K. and Chatt, A. EVALUATION OF HOMOGENEITY OF SELECTED REFERENCE MATERIALS FOR SELENIUM BY CYCLIC NEUTRON ACTIVATION ANALYSIS ICAAA-092 178

Rastikerdar, Samad A SOPHISTICATED IRRADIATION FACILITY FOR THE STRONGEST Am-Be NEUTRON SOURCE OF THE WORLD ICAAA-093 180

Rommel, M., Gehrbish, Sh. and Langrock, E.-J. THE POSSIBILITY OF AGGREGATE IDENTIFICATION IN CONCRETE BY PHOTON-ACTIVATION-ANALYSIS (PAA) ICAAA-094 182

Rossbach, M. and Stoeppler, M. FACILITY FOR PROMPT GAMMA ACTIVATION ANALYSIS OF BIOLOGICAL SAMPLES WITH COLD NEUTRONS AT THE KFA-Julich ICAAA-095 183

Rossbach, M. and Byrne, A.R. RADIOCHEMICAL NAA OF PLATINUM GROUP ELEMENTS IN BIOLOGICAL AND ENVIRONMENTAL SAMPLES ICAAA-096 186

Saiki, M., Vasconcellos, M.B.A. and Rogero, J.R. ANALYSIS OF BRAZILIAN SNAKE VENOMS BY NEUTRON ACTIVATION ANALYSIS ICAAA-097 188

w Salagean, Maria, Pantelica, Ana and Brad, I. MICROELEMENT CONTENT IN LEAVES AND FRUITS OF HIPPOPHAE RHAMNOIDES (L) PLANT DETERMINED BY NEUTRON ACTIVATION ANALYSIS ICAAA-098 190

Sarmani. Sukiman, Wood, Abdul Khalik and Hamzah, Zaini THE DETERMINATION OF ARSENIC, MERCURY AND SELENIUM IN MALAYSIAN SEA FOODS BY INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS ICAAA-099 132

Shmanenkova, G.I., Schelkova, V.P., Uritskaya T.P. and Volkova, L.V. DETERMINATION OF RARE EARTH ELEMENTS IN MINERAL RAW MATERIALS AND RARE EARTH INDUSTRY PRODUCTS BY NEUTRON ACTIVATION ANALYSIS ICAAA-100 194

Shtangeeva, Irina SHORT AND LONG PERIOD VARIATIONS OF THE ELEMENT COMPOSITION PLANTS AND SOIL IN LENINGRAD ICAAA-101' 196

Shulepnikov, M.N., Firsov, V.I., Kiseliova T.T., Rabinovich, B. Sysoeva, N.S. and Kondratieva, G.I. HIGH-FLUX NUCLEAR REACTOR IN ANALYZING SUPER-PURE METALS AND SEMI-CONDUCTORS ICAAA-102 198

Sima Octavian NEUTRON FLUX FLUCTUATION AND THE PRECISION OF NEUTRON ' ACTIVATION ANALYSIS ICAAA-103 200

Smakhtin, L.A. and Shevaldin, O.A. STUDIES ON THE NON-UNIFORMITY AND REPRESENTATIVE SAMPLING BY NAA ICAAA-104 203

Smakhtin, L.A., Filippova, N.V., Miglina, N.V., Shokel E.S. an Shutova, I.N. THE USE OF UNIVERSAL COMPARATOR METHOD IN LARGE-SCALE NAA • ICAAA-105 205

xn Smakhtin, L.A., Mekhryusheva', L.I., Filippova, N.V., Miglina, IM.V. and Sinitsyna, T.S. THE DETERMINATION OF RARE-EARTH ELEMENTS IN ENVIRONMENTAL OBJECTS ICAAA-106 207

Solodukhin, V.P. COMPLEX OF PHYSICAL METHODS OF ANALYSIS TO INVESTIGATE ELEMENTAL COMPOSITION OF NATURAL HYDROCARBONS ICAAA-107 209

Song Quanxun AN AUTOMATED SYSTEM FOR INAA ICAAA-108 210

Spiridon, Stefania and Spiridon, Gheorghe NEUTRON ACTIVATION ANALYSIS OF CONSTITUENT MINERAL ELEMENTS CONTENT OF FEEDS-AND BIOLOGICAL SAMPLES ICAAA-109 212

Sun Jingxin and Wang Yuqi > INVESTIGATION ON BACKGROUND VALUES OF TRACE ELEMENTS IN SOILS OF CHINA WITH INAA I. THE BACKGROUND VALUES OF U, Th AND REE IN SOIL ICAAA-110 214

Sun Laiyan, Lu Fengying, Su Rongwei and Zhen Houxi DETERMINATION & EVALUATION OF TOXIC AND TRACE ELEMENTS IN CHINESE FOODSTUFFS ICAAA-111 216

Szabo, A.S. POSSIBILITIES OF APPLICABILITY OF PROMPT ACTIVATION TECHNIQUE IN THE FOOD CHEMISTRY ICAAA-112 218

Thakur, A.N. ISOTOPICALLY ANOMALOUS MERCURY IN METEORITES BY NEUTRON ACTIVATION ANALYSIS; A COSMOCHEMICAL APPLICATION ICAAA-113 220

Tian Jibing, Qian Qingfang and Chai Chifang STUDY ON THE DISTRIBUTION OF SELENIUM AND OTHER ELEMENTS BY NAA AND BIOCHEMICAL TECHNIQUE ICAAA-114 222

XI'- Tian Junliang, Liu Puling and Li Yaqi A STUDY ON ELEMENTAL PEDOGEOCHEMISTRY OF LOESS PLATEAU, CHINA, BY INAA ICAAA-115 225

Tian Wei-Zhi and Ni Bang-Fa FURTHER STUDY ON PARAMETERIZATION OF REACTOR NAA ICAAA-116 227

Tian Weizhi and Peng Lixin A STUDY OF SAMPLING REPRESENTATIVENESS OF IAEA RM SD-M/TM MARINE SEDIMENT BY INAA ICAAA-117 229

Tluchor, D., Stverak, B. and Ciganek, L. TRACE ELEMENTS IN THE HUMAN EYE TISSUE ICAAA-118 231

Tong Chunhan and Li Guodong A NEW METHOD FOR CLASSIFYING PARENT TYPE OF ROCKS CONTAINING DISSOLVED ORGANIC MATTERS ICAAA-119 232

Tong Chunhan, Liang Xingzhong, Li Guodong and Li Juchu NEUTRON ACTIVATION STUDIES ON THE GEOGAS FROM A HIDDEN GOLDEN ORE DEPOSIT ' ICAAA-120 .234

Trukhov, A.V., Naumov, A.P. and Ganzha, A.P. THE COMPTON RANGE SIMULATION OF A SPECTROMETER RESPONSE FUNCTION FOR THE ESTIMATION OF ACTIVATION METRELOGICAL CHARACTERISTICS ICAAA-121 236

Tsukada Masamichi, Yamamoto Daijiro, Endo Kazutoyo and Nakahara Hiromichi PRE-CONCENTRATION METHOD USING AN ACTIVABLE YIELD TRACER FOR NEUTRON ACTIVATION ANALYSIS ICAAA-122 239

Vaganov, P.A. and Chou Rongsheng NEUTRON ACTIVATION STUDY OF MONOMINERAL FRACTIONS OF DEEP- WATER OCEANIC SULPHIDES ICAAA-123 241

xw Vaganov, P.A. IRIDIUM AMONALY IN THE UPPER VENDIAN ICAAA-124 243

Vajda, I. and Toth, L. A BRIEF SUMMARY OF EMG'S MULTICHANNEL ANALYZER PRODUCT RANGE ICAAA-125 245

Vitali, Vanda AN APPLICATION OF DATA ANALYSIS AND EXPERT SYSTEMS TO INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS RESULTS: AN ANCIENT MATERIAL'S PERSPECTIVE ICAAA-126 247

Wang, Haiying DETERMINATION OF WHOLE-BODY PROTEIN IN SMALL ANIMALS BY IVNAA ICAAA-127 2^

Wang, Haiying BACKGROUND INVESTIGATION ON THE DETERMINATION OF NITROGEN BY IVNAA ICAAA-128 251

Wang Jun, Chen Da and Qian Shaojun NEUTRON ACTIVATION ANALYSIS OF GEOLOGICAL ROCK MATERIALS ICAAA-129 253

Wang Xinfu, Zhu Guanghua, Shen Xinyin, Xiong Duanggui, Wu Xueqin and Sun Youping A P1XE STUDY OF THE EFFECTS OF THE ZINC-SMELTING WITH AN INDIGENOUS METHOD ON SURROUNDING ATOMSPHERIC ENVIRONMENT ICAAA-130 255

Wang Yinson, Tan Mingguang, Zhi Min, Zhuang Guisun and Cheng Yuandi DISTRIBUTION OF SOME ELEMENTS IN HUMAN HAIR AND INTERNAL ORGANS DETERMINED BY NAA ICAAA-131 257

Wang YunLiang THE DIAGNOSTIC PRINCIPLES AND PROGRAM OF TRACE ELEMENT ABUNDANCES ON THE PETROGENESIS AND MANTLE EVOLUTION ICAAA-132 259

XV Weginwar, R.G. and Garg, A.N. MULTIELEMEIMTAL NEUTRON ACTIVATION ANALYSIS OF DUST PARTICULATES FROM A CEMENT FACTORY IN CENTRAL INDIA ICAAA-133 261

Wei Lun-cun, Bao Shanglian, Yang Qixiang and Yang Xihong QUANTITATIVE CALCULATION OF THE CHARGED PARTICLE ACTIVATION ANALYSIS WITH CHANNELING ICAAA-134 263

Wu Yuguang and Zhao Junlin DETERMINATION OF TRACE ELEMENTS IN SAMPLES OF ANTARCTICA BY NEUTRON ACTIVATION ANALYSIS ICAAA-135 265

Wu Zhiqiang SEPARATION AND PURIFICATION OF 99-Tc FROM SIMULTING HIGH- LEVEL RADIOACTIVE LIQUID WASTES ICAAA-136 267

Xiao Jiazhu DETERMINATION OF 14 TYPES OF CHINESE TEA BY INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS ICAAA-137 269

Xiao Jiazhu SIMULTANEOUS DETERMINATION OF N, P, K, IN PLANTS BY 14MEV NEUTRON ACTIVATION ANALYSIS (FNAA) ICAAA-138 271

Yang Huazhong DETERMINATION OF SOME TRACE ELEMENTS IN HAIR OF DIABETICS BY ENERGY DISPERSIVE FLUORESCENCE METHOD ICAAA-139 273

Yang Huazhong and Song Shizhan ANALYSIS OF ELEMENT CONTENTS IN FOSSILS OF THE ANCIENT VERTEBRATES USING 241-Am XRF METHOD ICAAA-140 275

Yang Ruiying A PRELIMINARY STUDY ON THE TRACE ELEMENT GEOCHEMISTRY OF BASALTIC ROCKS FROM THE TANGBALE IN THE WESTERN JUNGGAR, XINJIANG, CHINA ICAAA-141 277

XVI Yang Shao jin and Zhang Yi Ming IDENTIFICATION OF MARINE AEROSOL COMPONENT BY COMBINED NEUTRON ACTIVATION ANALYSIS AND SCANNING ELECTRON MICROSCOPY WITH X-RAY ANALYSIS

ICAAA-142 279

Ye Zongyuan, Li Yubing, Ding Shengyao, Bao Zongyu, Yang Yiaoyun and Rong Chaofan AN INVESTIGATION OF METHOD FOR DETECTING EXPLOSIVES ICAAA-143 281

Yeh, S.J., Tseng, C.L. and Wei, J.C. PRECONCENTRATION FOR NEUTRON ACTIVATION ANALYSIS ICAAA-144 282

Zhang Weicheng, Zhang Tianmei, Zeng Wenbing and Lei Xiangguo DETERMINATION OF 13-C IN BREATH SAMPLE BY PIGE ICAAA-145 285

Zhang Xiaofeng, Ma Jianguo, Qin Junfa and Xiao Lun MULTIVARIATE STATISTICAL TREATMENT OF PIXE ANALYSIS OF TRADITIONAL CHINESE MEDICINE ICAAA-146 287

Zheng Jian and Zhang Guisun DETERMINATION OF TRACE ELEMENTS IN SUBCELLULAR FRACTIONS OF HUMAN LIVER BY INAA ICAAA-147 289

Zhong Ming, Feng Songlin, Liu Nianqing, Ren Minqin, Zhang Xiaofeng and Yan Linna PIX ANALYSIS OF CHEMICAL COMPOSITION OF GRAPHITE PHASE IN CAST IRON ICAAA-148 291

Zhou Dehai RADIOCHEMICAL SEPARATION OF 199-TL FROM THE AU TARGET BOMBARDED WITH a-PARTICLES ICAAA-149 293

Zhuang Guisun, Wang Yinson, Tan Mingguang, Zhi Min, Wang Yongjia and Zhuang Fulin PRELIMINARY STUDY OF TRACE ELEMENTS IN HUMAN BRAIN TUMOUR TISSUES BY INAA ICAAA-150 295

xvn LATE CONTRIBUTIONS

Ding Xixiang, Chen Baoguan and Yang Yueqing STUDY ON EVOLUTION OF GRANITE-PEGMATITES IN PEGMATITIC PROCESS BY MEANS OF NAA ICAAA -151 297

Fisher, E. M. and Dong Naisheng

SAMPO 90 :AN ACCURATE AND VERSATILE TOOL FOR THE GAMMA SPECTROSCOPIST ICAAA -152 299

Peisach,M. , Pineda, C. A. ,Pillay,A. E. and Themistocleous ,T. DETERMINATION OF ALUMINIUM AND SILICON IN ZEOLILES BY PIXE ICAAA -153 301

Soltanieh,A. A. ,Pazirandeh,A. ,Rahimian,N. and Salehi, M. PROMPT GAMMA NEUTRON ACTIVATION ANALYSIS OF COAL AND COPPER ORE SAMPLES ICAAA -154 303

Wang Ke and Li shenzhi NEUTRON ACTIVATION ANALYSIS IN MNSR ICAAA-155 305

Zhang Weihua and Cao Chuanru DETERMINATION OF 30 ELEMENTS IN SEDIMENTARY SAMPLES BY INAA WITH MNSR REACTOR ICAAA -156 307

Park,K. S. ,Kim,N. B. ,Woo,H. J.,Kim,D. K. ,Kim,J. K. and Choi,H. W. DETERMINATION OF IMPURITIES IN HIGH PURITY SILICON BY INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS ICAAA -157 308

Park,K. S. ,Kim,N. B. ,Woo,H. J. ,Hong,W. and Chun ,S. K. A STUDY ON KOREAN ANTHRACITE BY INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS ICAAA -158 310

Seymour,R. and Cox,J. USING LIBRARY —DIRECTED ANALYSIS FOR SINGLET AND MULTIPLET PEAKS ICAAA -159 312

XVB1 TRACE AND TOXIC ELEMENT DETERMINATION IN DRINKING WATER OF IRAQ BY NEUTRON ACTIVATION ANALYSIS

S.M.AL- JOBOORI Nuclear Resarch Ceentre, Tuwaitha, Baghdad, IRAQ. M.B.H. AL- BEDRI,H.A.A.HASSAN. Physics Department, College of Science, Baghdad University, Baghdad, IRAQ.

This paper is a part of a research project on foodstuff analysis,using

Instrumental Neutron Activation technique for the determination of the concentration of trace and toxic elements . This technique has been applied for determination of the concntration of 23 elements in drinking water collected from 30 locations across Iraq. Several authors [1-3] have used the preconcentration technique of the water by evaporation and freeze drying,followed by neutron activation analy­ sis for determination of multielement con centration levels in water.

The samples were collected using polyethylene bottle of 2 liter, pre­ viously cleaned with concentrated nitric acid and rinsed with double distilled water. 5ml of nitric acid was added to the drinking water in order to prevent loss of trace elements by adsorption on the container wall,and the sample was concentrated by evaporation at 70-75 C using ther mostaically hot plate to reduce the volume from 1L to(15-20) mL.

The concentrated sample was carefully bransferred from the beaker and placed in a quartz bottle of 50ml under infrared lamp at low heat and then kept at an oven at 70 C to be dried .

1 A bout 50 mq of each samples and standard were irradiated in IRT-5000 11 -2-1 13 Reactor Cor 5 win and 6h. at a duxes of: 7x10" n.crn S and 2.3x10 -2 -1 n. cm S respectively. The samples and standards were counted using Ge(Li)and Hp Ge detectors with a resolution (FWHM ) of 2.5 and

2.0 Kev at 1332 Key of 60Co respectively. The counting system was linked to on- line computer for instant analysis of the gamma-rays.

The interferences from other radionuclides and other nuclear reac­ tions have been corrected in the present work. The accuracy of our method was assessed by the analysis of AGV-1,SL-1 standard reference materials. A good agcament has baen achieved between the present values and the recommended values Table-1 . The range concentration of

23 elements in Iraqi drinking water has been determined Table-1 .

[1]. HABIB, S., MINSKI,M.J.,J.Radioanal. chem. 63(1981)379.

[21. NDIOKWERE,Ch.L.,GUINN, V.P., J. Radioanal. chem. 79(1983)147.

[3]. MILLEY,J.E, CHATT,A.,J. Radioanal.chem. 110 (1987)345.

2 Table 4 anges and mean concentrations or trace elements in Iraqi drinking water (ug/M ~" "ELEMENT RANGE MEAN±S7D7

Na* 2.40 _235.4 57.4+50.3 Mg* 0.55 _10.13 4.82i2.3fa Al* 0.07 _1.68 0.47±0.38 Si* 1.10 _18.04 3.2113.78 CI 0.d3?_15.96 5.4517.18 Ca* 19.10_236.9 85.4+57.9 Sc 0.013_0.53 0.08+0.124 V 0.766_4.02 1.66 +0.78 Cr 0.363_5.29 1.65+1.42 Mn 0.16 _16.5 8.1416.7 Fe 35.0 _1425. 238.1378. Co 0.045_0.69 0.27+0.24 Zn 7.93 _1615. 248.1343. As 1.03 _6.24 2.8511.63 Br 0.10 J29.8 4.8217.65 Rb 0.95 _4.11 2.61+1.29 Sr 0.41 J2.65 1.1810.703 Mo 0.183_16.1 5.0913.84 Sb 0.18 _1.99 0.4910.47

I 0.63 _6.45 3.5414.11 Ba J2.12_315.6 88.1186.4 Ce 0.145_2.18 0.8110.74

U 0.218_4.316 1.3510.94

* rhg/1 3 EXPERT SYSTEMS FOR NUCLIDE IDENTIFICATION AND INTERPRETATION OF GAMMA SPECTRUM ANALYSIS

Pertti Aarnio, Timo Hakulinen, Joima Routti Helsinki University of Technology Nuclear Engineering Laboratory SF-02150 Espoo, Finland

Gamma spectrum analysis is currently a widely used tool in many fields. Correct quantitative identification of radionuclides in a sample is often vital when making decisions for further actions. For example, finding fission products in a sample may suggest a radioactive release from the nearby nuclear power plant. Careful analysis, however, may prove that the fission products are due to nuclear weapons test or from a nuclear reactor of different type. In this case shutdown of the neighbouring reactor would be a costly mistake. The decisions must be correct and done quickly. This requires a substantial amount of expertise on the part of the laboratory personnel. Full quantitative identification of a complex spectrum takes many hours. There are several good computer codes available for the automated analysis of gamma spectra. These include program MicroSAMPO [1] developed in our laboratory. The nuclide identification is an iterative process where the analyst aims to find correct nuclides by decreasing the amount of possibilities by trial and error. Although the process of identification is quite complex, it can be formulated using "rules of thumb" combined with exact mathematical analysis. Thus, it is feasible to build an expert system where the knowledge of a human expert" concerning the problem is converted into explicit rules. These rules can be processed by using an inference engine, a specialized program for reasoning. There are two main strategies of inference in an expert system, for­ ward chaining and backward chaining. In forward chained reasoning

4 initial data are brought into system after which the inference engine checks validity of rules in the system and fires every rule it can. If the fired rules cause further rules to become valid, the process continues until no more valid rules exist and one has, hopefully, reached a solu­ tion. In backward chaining the user may ask a question, that is, state an assertion, which the inference engine tries to validate. Rules on which the truth value of the question depends are checked backwards if they can be validated until the answer is found. Standard approach to the identification problem is forward chaining, with which thor­ ough analysis of a spectrum can be performed. Backward chaining comes in handy when one wants to know, for example, whether some specific isotopes are present in a sample. We are currently developing an expert system that will carry out the quantitative nuclide identification with minimum of user interven­ tion. Reasoning process is performed in a LlSP-based expert system development environment, Gold Works, where rules and data struc­ tures are represented as LlSP-objects. The system uses a database containing over 2000 radionuclides with about 48000 gamma transi­ tions [2] together with a dedicated database manager. Spectra are provided in preprocessed format, where peak energies, intensities and backgrounds with corresponding error estimates have been calculated using MicroSAMPO. In the first phase the expert system should be able to identify with good accuracy gamma spectra of arbitrary com­ plexity and to compute corresponding activities, but the possibilities for system development extend further. When the amount of radionu­ clides in a sample is known it is possible to use this knowledge in a more general level in a decision support system. This system should help to make decisions concerning the origin and future development of the measured radioactivity as well as give recommendations for appropriate measures to be taken. [1] P.A. Aarnio, J.T. Routti, J.V. Sandberg, Journal of Radioanalyt- ical and Nuclear Chemistry, 124 2 (1988) 457-466. [2] G. Erdtmann, W. Soyka, The- Gamma Rays of the Radionuclides. Verlag Chemie GmbH, Weinheim 1979.

5 THE DETERMINATION OF TRACE AND MINOR ELEMENTS IN BREAST CANCER TISSUE

Bruce Adams Department of Nuclear Medicine, Groote Schuur Hospital and UCT Observatory, 7925, South Africa.

Dherendra Gihwala School of Science, Peninsula Technikon, P.O.Box 1906, Belville, 7535, South Africa.

Max Peisach National Accelerator Centre P.O.Box 72, Faure, 7131, South Africa.

David Dent Department of Surgery, Groote Schuur Hospital and UCT Observatory, 7925, South Africa.

Essential trace elements play an important role in regulating biological processes as agents which inhibit or activate various enzyme systems. Experimental data has impli­ cated trace metals as playing a possible role in the aetiology of cancer. An elemental analysis of breast cancer tissue was made in an attempt to acquire information regard­ ing the possible causes of the disorder. Certain studies showed an increase in the con­ centrations of specific trace metals in breast cancer tissue.[l,2] Other investigators found a deficiency in certain trace metals in certain malignancies including renal adenocarcinoma and melanoma, and patients with these disorders have been treated with some success by replacing these elements as part of the therapeutic regime. [3]

Prompt Gamma-ray and X-ray spectrometry - PIPPS and PIXE were used to deter­ mine the relative concentrations of trace and minor elements in breast cancer tissue. These concentrations were compared with those obtained for tissue from benign breast disease and normal breast tissue. Other analytical methods to which these tissues were subjected include: X-Ray Fluorescence; Voltametry-Polarography; Emission Spectrometry; UV/Visible Spectrophotometry and Atomic Absorption Spectrometry. PIXE and PIPPS are compared with these other analytical processes.

Multivariate statistical methods were applied in attempts to determine the inter­ relationships of the various elements and to define the relative importance of single or groups of elements. Cluster analysis, multi-dimensional scaling and correspondence

R analysis techniques were used to determine the relationships of the different elements.

Specific attention was given to the following elements: vanadium, tungten, molyb­ denum, selenium, tin, chromium, zinc, copper and iron.

These techniques were also used to determine the concentrations of the elements in the serum of these patients in an attempt to identify a marker which might allow for the early diagnosis of breast cancer.

[1] Risk S.L. and Sky-Peck H.H. Cancer Research, 44 (1984) 5390-5394. [2] Ehud J., Margolioth M.D., Schenker J.G., and Chevion M. Cancer 52K(1983) 868- 872. [3] TallbergT., Mahlberg K., Kalima T., Present Status of Non-Toxic Concepts in Can­ cer, Kargar, Basel (1987).

7 CHARGED PARTICLES ACTIVATION IN ANALYSIS OP PURE MATERIALS

Alexandrova G.I., Shmanenkova G.I., Pugatcheva O.P. State Institute for the Rare Metals "GIREIMET", Moscow, USSR

Charged particles activation with nHe, p, d as the basis for sensitive methods of oxygen, carbon and nitrogen deter- mination (I0~ -10" %) is used for high purity materials in­ vestigation as well as mass-spectrometry, neutron-activa­ tion and some other techniques. To estimate purity of tho­ se semiconductor materials, in which gas-forming impurities are limited, the techniques have been developed.

For oxygen, carbon and nitrogen determination in silicon, germanium, gallium arsenide, gallium phosphide and other bulk crystals and structures, as well as in a large group of metals. According to the developed techniques oxygen is determined with 13 MeV He ions, carbon with 13 MeV 'He ions or with 3-5 MeV deutrons and nitrogen with 6-10 MeV protons. Having accelerated flows of these particles one may choose optimum conditions for the analysis and reduce or even completely eliminate interferences on the adjacent light element nuclei. Thus, boron presence as a dopant in some silicon grades makes the helium-3 ions usage for car­ bon determination impossible. This is also typical for the gallium arsenyde prepared by the Czochralski technique un­ der a molten layer of BpO*. In this case the accelerated deutrons are used for carbon determination.

The best experimental detection limites for these methods which takes into account the etching and the matrix acti­ vity is 10 - 10"'% weight.

8 PRECISE 14 MEV NEUTRON ACTIVATION ANALYSIS

Andreev A.V., Varich O.M., Makarov S.A. State Institute of Rare Metals 109017* Moscow J-17, U.S.S.R.

Besides of traditional domain of activation analysis appli­ cation, trace element analysis, this method now is success­ fully applied for precise (with accuracy better than 1 % rel.) determination of element macroconcentration. In the most extend it is valid for 14 MeV activation analysis.

Development of precise analysis techniques is much more dif­ ficult and time-consuming problem than development of just high-sensitive ones. That is resulting from necessity to take into account a number of sources of systematic and random errors with make contribution to total accuracy more than 0.1} rel.

Investigations of the error sources of 14 MeV activation analysis made in the present work shown that the value of all random error sources except of counting statistics can be made as low as 0.1% rel. Because of trie spectroscopy sys­ tem count rate capability, it is complicated to lower the value of statistical error to 0.1% rel. especially when short-lived nuclides are used.

The most probable sources of systematic errors, making con­ siderable contribution to the overall accuracy are: 1. Certificated element content in the standard. 2. The difference of neutron flux self-shield effect and ]f-ray self-absorption in the samples and standards.

9 3. The certificated value of half-life period of the nuclide analysed. 4. The affect of the total counting rate of spectroscopy system during analysis of samples and standards.

The results of our study and developed techniques make it possible to decrease the total contribution of different sources of systematic errors to the value of 0.3 - 0.5 % rel. With the total accuracy of the large variety of materials and elements determined is 0.2 - 0.8 % rel. The results are given in Table 1.

Table 1. Precision determination of main components in some compounds and compositions (confidence probability P=0.95)

Sample Mas3,mg Element Concentration S- determinned % mass

RuO, 193-8 Ru 25.3 + 0.4 0.0057 0 75.1 + 0.7 0.0045

Pb2Ru206(Nd) 521.7 Ru 29.8 + 0.5 0.0076 Pb 32.9 + 0.5 0.0077 Nd 20.7 + 0.2 0.0055 0.0080 YBa2Cu30?_x 6235.5 0 16.14+ 0.09

Ce02 2584.1 0 20.28+ 0.13 0.0080

Pr205 2175.8 0 25.90+ 0.22 0.0080 V-Al 1234.6 V 79.5 + 1.5 0.0080 Al 23.3 ± 0.2 0.0034 LiNbO- 150.5 Nb 65.3 + 0.4 0.0030 4131«6 0 31.3 + 0.2 . 0.00(46 V-Nb-Zr 531-3 V 62.4 + 1.4 0.0081 Nb 33.8 + 0.6 0.0051 Zr 4.1 + 0.2 0.015 S- - relative standard deviation of mean.

10 STUDIES OF DISTRIBUTION OF CHEMICAL ELEMENTS IN SUSPENDED MATTER AND BOTTOM DEPOSITS OF CONTINENTAL SHELF OF EASTERN CHINA SEA USING NEUTRON ACTIVATION ANALYSIS V.V.Anikiev+, S.K.Prasad, T.Yu.Polyanova, G.M.Kolesov. V.I.Vernadsky Institute of Geochemistry & Analytical Chemistry, USSR Academy of Sciences, Kosygin Street 19, 117975, Moscow V-334, USSR; +Institute of Pacific Oceanography, USSR Academy of Sciences (DVO),Radio Street 7,690052,Vladivostok,USSR. Recently activation analysis is considered to be one of the most modern mechods of analyses. This tool is used in carrying out wide range of investigations between dry and ocean currents to understand'formation of new sedi­ ments and to undertake basic measures to protect sea and its surroundings from pollution. Keeping in view these two problems a small portion of the upper layer of the bottom sediment of Eastern China sea-shelf was chosen. This layer is formed by the direct influence of solid waste which was carried into the sea by the rivers Yunzi and Huanke. Determination of chemical elements in the samples was undertaken with the help of Neutron Activation Analysis. Two types of irradiation were made for this purpose. In the first case samples were irradiated with^fast and _2 thermal neutrons under a flux of 1,2 X 10 ^neutrons cm s for 20 hours, and in the second case the samples were irradiated in cadmium filter for period of 80-100 hours. The sediment samples collected weighing in the range 15-20 mg and 50-60 mg, respectively, were analysed. Irradiated samples were analysed at different time inter­ vals to avoid interferences of radionuclides. So after lapse of 5 days and 3 weeks measurements were carried out with the help of a Ge(Li) semiconductor detector, multichannel analyser coupled with a microprocessor. The gamma-spectra and elemental concentrations were evaluated using a special computer programme. The following groups of elements were used as indicators for different natural processes: Alkali metals (Na,K,Rb,Cs) determine change in composi­ tion of clay particles. Distribution pattern of lithophilic elements (Fe,Sc,Co, Cr) finds out the possibility of judging the relationship between surface sedimentary minerals and deep sedimen­ tary minerals.

11 Carbonaceous materials can be compared by knowing the composition of Oa and Ir. Distribution pattern of rare-earth elements (La,Ge,Sm, Eu,Tb,Yb,Lu) provides information of the influence of the processes like hydrolysis, oxidation, recovery, biological concentrations, complexation and sorption on the fractionation of chemical composition of sedimen­ tary materials. Rare elements (Th,Hf,Ia) give supplementary information necessary to have precise knowlege of assumptions and hypotheses. Distribution of highly toxic elements like Sb and Gr decides the important link of these elements with waste disposal and river drainage. Distribution characteristics and composition of macro and micro elements provide evidence for the movement of sedimentary material between land and ocean that takes place with fractional composition of this material under the influence of different geochemical processes.

12 Elemental Characterisation of Airborne Particulates at two Nigeria locations during the Harmattaa season.

0.1. Asubiojo*, I.B. Obion**, E.A. Oluyemi*, A.P. Oluwole** and N.M. Spyrou***,

•Department of Chemistry, Obafemi Awolowo University, Ile-lfe, Nigeria.

••Department of Physics, Obafemi Awolowo University, Ile-lfe, Nigeria.

•••Department of Physics, University of Survey, Guilford, Survey, U.K.

ABSTRACT

Air Particulate samples collected during the harmattan season at two different locations - Kano in the Northern part, and Ile-lfe in the Southern part of Kigeria, were analyzed for up to 30 elements using a combination of Instrumental Neutron Activation Analysis and X-3ay Fluorescence Spectrometry.

The total suspended particulate in Kano i3 much higher than Ife, resulting in much higher elemental concentrations in the former than the latter, in some cases by as much as one order of magnitude (Table 1). For example, the^mean concentrations of Si and Pe in Kano are 270ug/m3 and 21ug/m-5 respectively compared to 73 #/E3 and 2 g/m3 respectively in Ile-lfe, However, the mean concentrations in Ile-lfe are ,^\ comparable to those of Summer/Early Vinter in Toronto, Canada^ \ for most of the elements determined.

Enrichment factors were calculated for elements in the airborne particulates at the two locations, using Titanium as the reference element. At both locations, the elements Ka, Mg, Al, I, K, Ca, V, Cr, Kn, Pe, Zn and Rb exhibited low enrichment factors (E.P. 3) which Co, Ni, Cu, pb and As exhibited high enrichment factors (E.P. 10). With the exception of V, which usually has significant anthropogenic contributions, most of the elements with low enrichment factors are generally of natural origin while those with high enrichment factors are conventionally associated with anthropogenic sources. Enrichment factors of about 100 and 10 were obtained for Fb and As respectively at both locations, which should give cause for concern because of the toxicity potentials of these elements. However, it is noted that the Nigerian samples are still less enriched in Pb than Toronto samples.

13 In Kano, most of the elements are concentrated in the medium particle-size range of 3-1,5 m, with the exception of Si which peaks at 3 m and 0.1*9 in» representing a mixture of medium and fine-sized particles, and S which has a clear bias for fine particles, understandably arising from fuel combustion. These results are not exactly in agreement with the results of KcTainsh and Walker (2) who found that Kano harmattan dust in 1^82 was mainly distributed between fine ( 2. m) and coarse particles ( 7*6 m).

For the Ile-Ife samples, we have a progressive increase in concentration of virtually all the elements, from coarse to fine particles. Here, it is evident that most of the elements are derived from a common source of fine particles, an indication of dust from the Sahara desert whose coarse components have been deposited along the way before reaching Ile-Ife, a Southern town some 200kra away from the source of the Sahara dust. Like Cawse and Beavington (3) observed earlier for Bagauda in the Northern part of the country, contribution of local entrained soil is minimal. It is also in agreement with Adedokun _et _al (k) who found that Ife harmattan dust is mainly composed of fine particles with a mode of 2,5 m. In line with the results of these previous workers, there is a higher concentration of most elements in the fine particle range in Ile-Ife than in Kano. Table 1» Elemental Concentrations in Airborne Particulates.(ns/nr) SleKent Ile-Ife Kano Al 18298 71360 As 1.96 Ca 5036 21*111* Co 90 230 Cr 17 131 Cu 219 U76 Fe 2072 21203 K 2995 69U1 Mg 2360 7959 Kn 93 655 Ha 13U9 6998 Mi 96 . 298 P 119 6I46 Pb 106 883 Rb 26 1*09 S 729 1723 Si 73363 269590 Ti • i+68 361*6 V 2.23 11 Zn * 90. '

14 REFERENCES

T.G. Pringle and R.E. Jervis, J. Radioanal. Nucl. Chem. 112 (1987) 210. "

G.H. McArinsh and P,H. Walker, Z. Geomorph. N.F., Vol. 26, No.J4: (1982) U17.

F. Beavington and P.A. Cawse, Sci. Tot. Environ. 10, (1978) 239.

J.A. Adedokun, V.O. Qnofurieta, O.A. A.dedeji, J. Theor. Appl. Clim. (in press).

15 Determination of 12 Rare-Earth Elements In High-Pure Sc203 By Prctreatment Neutron Activation Analysis

Bao Wei Dong Zhou Man Fang Yuan Ge.n Le

Beijing General Research Institute Of Non ferrous Metals

A method for the determination of 12 rare-earth elements in high-pure Sc,03 by pretreatment neutron activation analysis has been described in this paper.The pre treatment proress of samples is that the scandium is extracted by PMBP and butyl acetate at dilute acid. The Scandium is separeted from rare-earth elements.The results of radioisotope tracer experiment proved that the decontamination factor of scandium is over 4.5X10" and the chemical yield of rare-earth elements is over 96%.The method can meet the needs of neutron activation analysis.

After pretreatraent the sample is quantitatively transferred to 12 layers 12 x 12mm XIN HUA quantitative filter paper and is dried at GO'C/ then is wrapped in a pure aluminium foil. Samples and corresponding standards are packed together and irradiated in low temperature channels of the heavy water reflective layer.The samples are irradiated for 5 hours and are cooled for 2 days for the determination of La,Pr, Sm,Ho and the others are irradiated for 20 hours and are cooled for 20 days for the determination of Ce,Nd, Eu,Gd,Tb, Tin, Yb, Lu. After irradiation and cooling, the samples are dissolved. The chloride solution of the sample is pr.ssed through a preequilibrated P204 column at a definite flow rate.The column is washed with different concentration HCL.Measuring soure is made. The gamma-ray spectra of the samples is measured by S-9fl multichannel y -spectrum system.

The measuring time is 300-600 seconds for standards and 1800-3600 seconds for samples.The experimental results and the detection limits are shown in following table.

16 Table,The experimental results and the detection limits(PFm)

I 1 1 1 1

name/element ] La | Ce | Pr j

99.991) Sca0, | 0.95+0.025 | 2.43+0.38 | 0.36+0.057 |

this purified Sc.O, I 0.076±0.0094 |<0.053 |<0.13 | ' The detention limits | 3.7X10" 15.3X10" I 0.11 I 1 1 i j

( 1 f ] [ Nd | Sra | En | Gd | Th | 0.96 + 0.042 (0.14+0.0028 I 0.21 + 0.0017 | <0. 29 10.048+0.0041 | H _, _j_ + h H <0.15 | 0.093+0.00062 | <0.004 |<0.25 |<0.014 |

0.15 |5.3X10" 14.0X10" J 0.25 | 1.2X10" |

l 1 1 1 1 Ho | Tm | Yb | Lu |

. 0.44±0. 0069 I 0.24+0.014 I 0.30+0.016 | 0. 055+0. 0033 |

, <0.035 | <0.023 I <0.023 | <0.0015 i

.3.5X10" 11.7X10" 12.3X10" | 1.1X10" |

The accuracy of standards is less than 3% and the accuracy of the method is less than 5^{.Radioisotope tracer analysis showed that the chemical yield for the separation of rare-earth elements using P204 column is over 96. 9%. The experimental results are reliable.The totat detection limit for the determimation of all 12 rare-earth elements is 0.63ppm. The method can be used to determine rare-earth elements in 99.9999% Sc,0,.

[1] Mao Jia Jun Zhu Da Chang «Seperation and preconcentration Methods in Inorganic Trace Analysis» Fudan University Press (1985)

17 STUDY 01' BRAZED iiZTD \ffiLDEC JOIBTO BY I'.iSTHODS OF RADIOGRAPHIC ACTIVATION ANALYSIS

^orzina I. G. , Gusev .i. 3., Lukin V. I., Rilniko'v V. S. L'ioscoiv Railway Transport Institute 1014-75 USSR, Moscow, GSP, A-55, Obraztsova, 15

Plash (n,°0 - radiograph was applied to study distribu­ tion of boron in both refractory nickel alloy joints bra­ zed by boron braze and parent material. Joints braaos of different composition containing boron as the principal component in charge of lowering of temperature in seam area were investigated.

The effect of surface treatment prior to brazing on boron distribution was studied. Depth of boron penetration into parent material and nature of its distribution in seam area were shown to depend on the kind of surface treat­ ment applied prior to brazing. Boron distribution in bra­ zed seam area depending on the shape of joint clearance was also studied.

Structure of zones of boron distribution in brazed soam area was investigated. Diagram of boron distribution in brazed joints studied was drawn up. Principal zones of seam area differing in boron distribution nature were distinguished. Diffusion zones were found on both sides of brazed seam which are not to be found by metallographical tests. Faulty operating conditions were detected under which sections lacking braze occur in seam clearance.

18 It was found that boron penetrates parent material by both diffusion of molt containing boron and diffusion of single atoms.

Isothermal annealing after brazing was found to cause boron re-distribution in all samples examined and its transition from seam area to parent material accompanied by widening of diffusion zone. Specific boron re-distribution among brazed joint zones was observed in samples subjected to isothermal annealing after brazing.

3oron distribution among zones of brazed joint was corre­ lated with its strength properties. Certain minimum width of brazed joint clearance which determines absence of sec­ tions with minimum boron content and corresponds to high strength properties' of joint was shown to exist.

(n,o£) - radiography tests, (p,o0 - microanalysis and x-ray microspectrum analysis were used to find out distribution of aluminium, magnesium and lithium (Al,Ivig,Li) in welded joints of aliKiiinium-magnosium alloys. Distribution of Li, Al and Mg in weld area was found to be uneven. Effect of heat treatment on re-destribution of the above elements was studied. Regimes of heat treatment which cause decrease in Li and other elements concentration gradients in welded jo­ int area were determined. It was shown that there exists certain correlation between distributions of Mg and Li, Al and Li. Oxygen concentrations were found to rise in welded joint area which occur at fatigne cracks. It was shewn that lithium may serve as indicating element (both in positive and negative aspects) to determine distribution of other elements during welding. Heat treatment of articles after welding was also shown to equalize concentration gradients of the above elements.

19 OAK LEAVES FEASIBILITY AS GASEOUS POLLUTION MONITOR

G. Capannesi, A. F. Sedda ENEA C.R.E. Casaccia, S.P. Anguillarese 301, Roma, Italy

A. Cecchi Istituto Nazionale di Fisica Nucleare, Largo E. Fermi 2, 50125 Firenze, Italy

A meaningful evaluation of air pollution in urban and in­ dustrial areas generally involve a great amount of measure­ ments over long time periods in order to minimize local microclimates and sampling fluctuations.

The approach of choosing a biological monitor as repre­ sentative of the area of interest is highly attractive in this respect.

In the past has been demonstrated that not only epiphytic plants (Lichens, Briophytes) have the capability of equi­ librating their mineral contents with the environment, but also superior plants, like evergreen oaks, "describe" quite well their natural environment.

In the present work a wide set of analytical data from INAA and PAA measurements on urban oak leaves (Rome) is examined in detail.

Elements Correlation and Clustering was performed on the raw data, so showing evidence of the capability of oak leaves as

20 gaseous pollution monitor.

Multiparameter Canonical Correlation Analysis and Principal Components Analysis were performed, by taking into account the analytical data and the characteristics of each of the 41 studied sites.

The capability of a quantitative description of the urban pollution, also in relation with specific microsituations, is investigated by Pattern Recognition Techniques.

21 STUDY OF TRACE ELEMENT IN HAIR SAMPLES FROM TWO CHILDREN AT DIFFERENT DATE BY USING INAA.

G. Capannesi, L. Renzi, F. Sedda ENEA C.R.E. Casaccia, S.P. Anguillarese 301, Roma, Italy

Jin Li-Yun1 Institute of Atomic Energy. P.O. Box 275(29), Beijing,China

Abstract: A study of trace element in hair samples from two different sex children at different date by using INAA has been carried out. The girl was born on Dec. 12,1973 and the boy was born on Apr.27,1977. Both of them were born and live in Roma. They are sister and brother. Each hair sample was collected from the whole head by using a pair of stainless steel scissors during hair-cut in barber shop. A total of 42 samples were collected, among them 10 for the girl and 32 for the boy. Before irradiation, the hair samples were washed separately by sonication in acetone and dried in a vacuum oven. Weigh about 1 gram hair sample in a plastic tube for irradiation. Standard pure solutions of the elements of interest and SRM NBS 1573(tomato leaves), SRM NBS 1571(orchard leaves) were used as comparison standard. Hair samples were irradiated at TRIGA MARK 11 reactor of ENEA,Casaccia. Long and middle-lived nuclides were produced through 3 0 hours irradiation in the rotatory rack with neutron flux of 2,6*1013n/(cm2*sec) . While the short-lived nuclides were obtained after 100 seconds irradiation in an in-core system provided with pnuematic transfer having neutron flux of 1,l*1012n/(cm2*sec).

1. As a visit-scientist worked in ENEA C.R.E Casaccia during 1989.

22 neutron flux of 1,l*1012n/(cm2*sec). The gamma-spectra of irradiated hair sample were measured by means of a Ge(Li) detector with a resolution of 1,9 keV (FWHM), efficiency 30 % and peak/compton ratio 57:1 at 1332 kev of 60Co photo-peak. The detector was connected to a "LIVIUS" 16k multi-channel analyzer with gamma-spectrum processing program, using several combinations of irradia- ti»i:; time, cooling time and counting time, forty elements were quantitatively analyzed. These elements are Al, Ag, As, Au, Ba, Ca, Cd, Ce, Cl, Co, Cr, Cs, Cu, Dy, Hf, Hg, I, In, K, La, Mg, Mn, Mo, Na, Rb, S, Sb, Sc, Se, Sm, Ta, Th, Ti,

Tm, Uf V, W, Zn. The following conclusions could be drqwn from the data obtained: 1, No regular changes were found for the trace element content in the hair as a function of sampling date. Some changes approximate to events such as breast fed term and puberty term may be shield by other multi- factors . 2, Significant changes for some trace element contents in a few hair samples have been observed due to known ex­ ogenous and endogenous deposition, for example 841107 sample. 3, The relative variability of trace element content in the hair is rather large for some elements such as K, Rb, while for some other elements is much small, such as Zn, Fe. 4, No significant differences for trace element content in the hair were found as a function of sex. Nevertheless, our data seem to indicate a trend towards higher con­ centrations in the girl. 5, The arithmetic mean of the hair trace element con centration measured in the two children are rather agreement with the comparable data reported for Italian population.

23 DETERMINATION OF REE ABUNDANCES IN MINUTE BIOGENIC APATITE BY NAA AND ITS GEOCHEMICAL SIGNIFICANCE

Chai Cliifang1, Ma Shulan1, Zhao Zhenliua2, Zhao Huilan2, Mao Xueying1, Ma Jiauguo1, Zhou Yaoqi1 1 Institute of High Energy Physics, Academia Sinica, P.O.Box 2732, Beijing 1000S0, China 2 Institute of Geochemistry, Academia Sinica, P.O.Box 91, Guiyang 550002, China

The biogenic apatites, like inarticulata and conodont, can be used indicators in the study of sedimentary paleoenvironment, since they are highly enriched in RES and bring the elemental geochemical signature of primitive marine sedimentary envi­ ronment [1]. However, analytical methods with high sensitivity are indispensable to determine the REE abundances in such small fossil samples, usually several to tens micrograms in weight. Recently, Chen, et al. [2] analyzed the REE abun­ dances in inarticulata by ICP. But it has some intrinsic disadvantages, e.g. large amount of sample and tedious chemical pretreatment, etc. For this reason, we used NAA to determine REE content in minute biogenic apatites, thereby deciphering their geochemical constraint on paleoenvironment.

The inarticulata and conodont fossil samples studied in this work are taken from the Cambrian-Ordovician boundary stratotype section at Dayangcha, Jilin province. Rinse the rock samples with 13% glacial acetic acid to remove the carbonate ma­ trix. Separate the acid-insoluble residues with the CHBi-3 heavy liquid. Pick out inarticulata and conodont fossil samples from the heavy fraction under binocular microscope. Carefully clean the biogenic apatite with bidistilled water in an ul­ trasonic cleaner to remove the detrital debris adhering to the apatites. Weigh the carefully cleaned inarticulata and conodont by a photoeletric balance (minimum readabilityiljUg). Due to small amount of sample, the neutron integral flux was 2xlOl&n/cm2 and the counting time was 104s or longer. In addition, a set of special dilute mix-standard was prepared to reduce geometric factor caused by difference between sample and standard in weight and size.

The REE abundances and their counting statistical errors of 12 inarticulata sam­ ples and 1 conodont sample are listed in table 1, where also included are the REE abundances of NASC as a normalized reference. The geochemical significance of our results will be discussed in the full paper.

24 Wright, J., et al., Geol.Soc.Amer., Spec.Pap., 196(1984)325. Chen, .T.N., et al., Aspects of Cambrian-Ordovician Boundary in Dayan China, China Prospect Publishing House, Beijing, (1986) pp.62-91.

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25 STUDIES ON SPECIATION OF TRACE ELEMENTS IN BIOLOGICAL

MACROMOLECULES

A. Chart* and C.K. Jayawickreme

Trace Analysis Research Centre, Department of Chemistry Dalhousie University, Halifax, Nova Scotia, B3H 4J1 Canada

Trace elements play an important role in the biological activities of living matter. A considerable amount of data on trace element levels of various biological tissues already exists in literature. In the past, many studies have been carried out to determine total elemental content. However, trace elements are mainly incorporated with proteins in biological matter. It is therefore important to isolate these protein-bound trace elements to identify the chemical species, and to characterize them for understanding their possible biological activities. Our interest lies in the development of analytical and bioanalytical methods for the characterization of metalloproteins and protein-bound trace elements in sub­ cellular fractions of bovine kidneys.

Characterization of a metalloprotein may be carried out by one of the three following techniques. These are: (1) isolation of the protein followed by measurement of its biological activity; (2) incorporation of a radioactive tracer into experimental animals, and subsequent measurement of the tracer activity; and (3) purification of the metalloprotein followed by direct measurement of the trace element by a suitable analytical technique. The application of the first technique is obviously difficult because of limited knowledge of the biological (enzymatic) activity of a new metalloprotein prior to its isolation and identification. Although the second technique is widely used, the question remains whether a short-term exposure to a radiotracer could label all the proteins of that element to the same natural proportion. We have opted for the third technique. We have recently shown that the last procedure can provide new and exciting results on metallo-proteins if appropriate techniques are selected and applied.

Biological macromolecular species can sometimes be separated according to their isoelectric points, mobility, size, charge etc., and then the trace elements present in the species can be identified by a suitable analytical technique. The bioanalytical techniques being employed in this laboratory to separate, purify and characterize metalloproteins in bovine kidneys include dialysis, pH variation, ammonium sulphate precipitation, gel filtration, ion-exchange and hydroxylapatite chromatography, chromatofocusing, isoelectrofocusing and isotachophoresis.

26 The metal determination technique should meet several requirements including multielement specificity, ability to analyze a few milligram quantities of solid and liquid samples instrumentally, and excellent precision, accuracy and sensitivity. Instrumental neutron activation analysis (INAA) is ideally suited for such purposes.

The biological essentiality of Se for animals was first evidenced in 1957. However, it was not until 1973 that an enzyme called glutathione peroxidase was proven to be a selenoenzyme. At present, Se is known to be a normal component of several enzymes, proteins and some aminoacryl transfer nucleic acids. Certain Se compounds have been reported to possess anti-carcinogenic properties. Almost all of the work on selenoproteins reported in literature involves the usage of 75-Se radiotracer in rats and mice. We are concentrating our efforts in the separation and purification of selenoproteins in bovine kidneys followed by direct measurement of Se by cyclic instrumental neutron activation analysis (CINAA) using the Dalhousie University SLOWPOKE-2 Reactor.

Selenoproteins are generally known to concentrate in the cytosol fraction of animal tissues. An unusual enrichment of about 75% of Se in the nuclei fraction of bovine kidneys attracted our attention for an in-depth study. About 98% of this Se is bound to proteins. An elaborate extraction method has been developed at four different pH (7.0, 7.5, 8.5 and 9.5) to fractionate several selenoproteins from the nuclei fraction. Extensive studies of the fraction at pH 9.5 show the presence of three new selenoproteins called Selenoprotein C1 (Se content of 1200 ppm, molecular weight of 30 000 daltons), Selenoprotein C2 (270 ppm, 70 000 daltons) and Selenoprotein C3 (360 ppm, 80 000 daltons).

In addition to selenoproteins, several other metalloproteins and protein-bound trace elements have been detected in both nuclei and cytosol fractions of bovine kidneys. The existence of an arsenoprotein (MW 27 000 daltons) has been confirmed. In addition, gel filtration experiments show the presence of several proteins containing Ca, Cd, Cr, Cu, Fe, Mn, Mo, V and Zn. Most of these metalloproteins and protein-bound elements have not yet been reported in the literature. A systematic study on their separation, purification and identification is being done. Details of the approach and methodologies will be presented.

27 NEUTRON ACTIVATION ANALYSIS OF RHENIUM IN ROCKS

Chen YInliang and Vang Xiaoling Southwest Institute of Nuclear- Physics and Chemistry P.O. Box 515-25, Chengdu, Sichuan, China

A simple neutron activation method for the determination of rhenium preconcentrated from rocks Is described. The preeoneentration Is based on a prel Iiuinary extraction separation with acetone and latter separation with TBP column to eliminate the metal Impurities. The chemical recovery of each sample was determined by an Isotope tracer technique using Re-186. The method has been applied to the determination of rhenium in rocks and the experimental results are very well. A sample and a known amount of Re-186 tracer In an teflon beaker (packed with copper beaker) and the mixture Is kepi: for 1 hour In a molten state In olee,trie stove. When the melt is cool, a amount of water are added and the teflon beaker is left for 20 min on a boiling water bath. Then the contents of the beaker are transferred quantitatively into a centrifuge tube and perform a two-fold extraction with 40 ml aceton saturated with 5 N KOH. Evaporate the combined aceton extracts to dryness In a beaker on a water- bath. The residue was' dissolved in 5 ml water and the resulting solution was passed through a column (h = 50 mm, d = 0 mm) packed with TBP. Thus all metal Impurities were eliminated. Perrhenlc acid together with washing liquors was collected in a teflon beaker. After treated with ammonia, thts solution was evaporated to a volume or 1 - 2 drops under an infrared lamp. Then it was transferred on a polyethylene foil and sealed with polyethylene. After the determination of the chemical recoveries, the penals and standards were irradiated in an reactor for 20 hours under the neutron flux of 1E13 n.cm(-2),seo(-l), cooled for 40 hours and counted with GefLi) detector.

28 PREPARATION AND CERTIFICATION OF THE HlffJAN HAIR REFERENCE MATERIAL

Cheng Yuandi, Wang Xuepeng, Qian Yine, Zhang Yuanxun, Tan Mingguang Shanghai Institute of Nuclear Research, Academia Sinica P.O.Box 800-204, Shanghai 201800, China

In order to meet the ever increasing requirements for the analytical quality control in application of hair analysis, a human hair refe­ rence material has recently been prepared and certified by Shanghai Institute of Nuclear Research, Academia Sinica.

Approxiamately 30kg of human scalp hair from normal male individuals was collected. After pre-cleaning steps, the hair samples were washed with a combined procedure of dilute non-ionic detergent, de- ionized water and acetone successively with stirring. The dried hair segments were pulverifsedto fine power (<120 mesh) by using a rotor- speed mill. Then the power was mixed thoroughly in a blender and dispensed into bottles, radiation sterilized through exposure to Co gamma radiation at 2x10 rads.

The homogeneity of this material was estimated by determining twelve of elements ( CU, Zn, Mg, K, Fb, Fe, Ca, Na, S, Al, Mn and Or ) on sample weight from 100 to 300mg by INAA, XRF and AAS. Using variance F-test, the results show this material satisfies the homogeneity criteria for a reference material. Results of examination on the stability of this material by XRF indicate no detectable difference between tests in the preservation period.

22 laboratories participated in the certification analysis of this material by using various established analytical techniques ( INAA, RNAA, AAS, ICP, AFS, POL, XRF, IMS and FIXE ). 17 certified values are obtained and the other 13 values are provided as the reference

29 values for this material ( see Tab.l ). Concentrations of these elements are comparable with the typical data for normals in litera­ tures.

This certified human hair reference material vjill toe of practical use for analytical quality control and assurance in laboratories engaged in toiomedical and environmental studies.

Table 1 Certified Values for the Chinese Hair Reference Material (in /u,g/g dry weight)

Element Content Element Content

Ag (0.35)* La (0.014)

Al 13.3 ± 2.3** Mg 105 t6 As 0.59 £ 0.07 Mn 2.94 ±0. 20

Ba (5.41) Mo (0.58)

Br (0.602) Na 266 l 12

Ca 1090 £ 72 Ni 3.17 ± 0.40

Cd 0.095 £ 0.012 P (184)

CI (152) - Pb 7.2 £ 0.7

Co 0.135 £ 0.008 ' S (4.69%)

Cr 4.77 £ 0.38 Sb (0.21) .

Cu 23.0 £ 1.4 Sc (0.00287)

Fe 71.2 ± 6.6 Se 0.58 ±0.05

Hg 2.16 £ 0.21 Sr 4.18 £ 0.14 I (0.875) V (0.069)

K (11.8) Zn 189 £ 8

* Values in parentheses are reference values

** Certified values, uncertainties given are £ 2 standard deviation

30 UNCERTAINTIES IN THE CHARGED-PARTICLE ACTIVATION ANALYSIS AT CYCLOTRON Era.Cincu and Al.Popa-Nemoiu Institute of Atomic Physic's, Cyclotron Laboratory P.O.Box MG-6, Bucharest, ROMANIA In the last years a number of works have revealed a growing interest in the Charged-Particle Activation Analy­ sis, as applied to different fields, especially for its ad­ vantage in investigating the thin surface layers of mate - rials, for its specificity and sensitivity in determining trace elements - up to several ppb -- as well as for the pos­ sibility of the simultaneous assay of many elements by a non-destructive way /l/. In defining the competitiveness of the method, the to­ tal uncertainty on the weight fraction values of the ele­ ments is a major parameter. This work deals with a detail­ ed survey of the uncertainty sources in CPAA, aiming at evidencing the largest ones and at comparing them with the requested standardized values /2/ and limits in applying this technique in industry. CPAA was generally developed at Cyclotron facilities at a medium energy range /3/. It consists of four main com­ pulsory stages : sample preparation, target irradiation, measurements of the nuclide induced activities - usually by y-ray spectrometry - and calculus of the weight frac - tions of the elements which generated them: the radioche­ mical procedures as auxiliary stages, are not taken into account. The "targetry" problems, that is the influence of sam­ ples characteristics on the accuracy of the final results of nuclear data measurements J2/, as the uncertainties in­ volved in the estimation of the incident energy of the acce­ lerated particles in the absolute beam current monitoring and those due to the instability and geometry factors in the irradiation and measurement conditions are discussed. An overall value of the reproducibility uncertainty for the latter combined sources was specially, evaluated in experiments conducted at the Cyclotron of the I.A.P.- in Bucharest - and is presented in this work : the maximum value of this stage was found £3% at a 95% confidence level. The uncertainties associated with the third stage of the analysis, involving the correct evaluation of the net area of a full energy peak (.location, shape, efficiency calibration, multiplet deconvolution, various corrections) and the absolute calibration of the y-ray spectrometer -

31 nuclear decay data included - are reviewed; the values range from 0.1% to values <10% , as function mainly of the statistical level of the peak and of the complexity of the Y -spectrum. Finally, three approaches may be taken to evaluate the weight fractions of the elements in the irradiated sample: a) the absolute method, using experimental data of the excitation functions of the microscopic nuclear cross sec­ tions, or calculated by appropriate models /4/, and absolute experimental monitoring of the particle fluence. b) the method proposed in /5/, in which several experi­ mental uncertainty sources are avoided and the final results use thick target activation yield data; the uncertainty va­ lues associated with the experimental cross section and ac - tivation yield data range from ^10% to 1.25& /6/ and ^8% to i,25% /7/, respectively; c) the standardization procedures, which may introduce a much lesser error, yet lead to questioning the accuracy and correctness of the standard used; ideally, the standard must be identical with the analyzed sample, although its elemental composition is not known in advance and irrespect­ ive of its origin. . In conclusions, the study reveals that the largest uncer­ tainty components are in the field of the fundamental nucle­ ar data amongst which the sample properties may be a- major factor and that the overall value is yet quite far from the admitted standardized value, noted as 1% /2/, and the limits useful for applying the CPAA technique in industry. References ' /!/ Barrandon, J.N., J. Radioanal.Chem. ,55 (1980) 317-327. J2J Wagemans.C., IAEA Specialists'Meeting on "The influence of Sample and Target Properties on Nuclear Data Measure­ ments", Geel (Belgium) 1987, Report INDC(NDC)-200/G, MY C1988) 13-17. /3/ Hoste,J., Op.de Beeck,J., Gijbels,R.,Adams,F.,Dan den Winkel,P. and De Soete D./'Activation Analysis", CRC Mo- noscience Series,Chapter V, Butterworth, London, 1971. /4/ Nowotny,R. , and Uhl.M. , "Handbook of Nuclear Activation Data", Technical Reports Series No.273, IAEA, Vienna (.1987) 441-477. /5/ Cincu Em., "Elemental Assay of Materials Without Stan­ dards Using CPA and Gamma-ray Spectrometry", Nucl.Instr. and Methds. Phys.Res. A 286 (1990) 388-394. /6/ Quaim, S.M., Radiochimica Acta 30 (1982) 147. /7/ Dmitriev,P.P., "Radionuclide Yield in Reactions with Protons, Deuterons , Alpha Particles and Helium-3", INDC-263, IAEA, Moscow, 1986.

32 LIGHT ELEMENTS DETERMINATION USING ACTIVATION METHOD AT THE IMPi! CYCLOTRON

B.Constantinescu, G.Pascovici, D.Plos/tinaru Institute of Nuclear Physics and Engineering Bucliar est, P.O. BoxfcIG-6, Romani a

During the past few years, elemental analysis methods (Pl'XE - for Z > 17 elements, PIGE for IT, 0, P, Na, Mg, Al, Si) using 4.7 MeV alpha particles at our variable- energy U-120 Cyclotron have been developed /l/. For the other light elements the charged-particle activation • method can be suitable. V/e present some results about P and S determination using 22 JileV alpha particles, 14 I.ieV protons respectively, and some considerations about the possibility to use in elemental analysis (especially for 0) fast neutrons produced by Cyclotron deuterons on a berrylium thick target.

So, for P we have used the reaction:

3 ^P(<*,n) ^Cl (T1/2 = 32.5 rain) E = 2120 keV

100 nA 22 MeV alpha particle beam was used for in air

33 irradiation (10-15 min) through a 100 jx Al foil. The samples (various polymers) were measured 15 min after th? end of irradiation using a 70 cm Ge(Li) detector in a lead shielded area. Triphenylphosphyne (CTOH-JCP) mixed with polyethylene standards were used. For polymers the sensitivity is about 5 ppm.

For S v/e have used the reaction:

s 3/ lG (P>n) ^'Cl (T1/2 = 32.5 min) Ji) ^ = 2120 keV in the same irra'diation and measurement conditions. Ammonium sulphide (NH^gSO^ mixed with polyethylene standards 'were used. The sensitivity for polymers is about 30 ppm.

Intense fast-neutron beams (7.8 x 10 n/cm4«s, E = 5 MeV can be produced using 13 MeV Cyclotron accelerated deuterons on a berrylium thick target. For 0 determination, the reaction:

1 1 T |o(n,p) ^ (T1//2 = 7.3 s) E-, = 6130 k-V is suitable 10 s irradiation and 20 s measurements with a 12.5 cm x 12.5 cm Nal(Tl) crystal can be used. In this mode, we can aloo determine Mg, Al, Si, Fe. The work is in progress.

/I/ Constantinescu, B. et al, Appl.Radiat.Isot. 37, 1 (1986) pp. 53-60.

34 AMAZON BASIN: TRACE ELEMENTS IN VARZEA SEDIMENTS

Elisabete A. De Nadai Fernandes; Epaminondas S.B. Ferraz; Luiz A. Martinelli & HelderdeOliveira Centro de Energia Nuclear ne Agriculture, USP P.O.Box 96 13400, Pirocicaba, Sao Paulo, Brasil

The Amazon Basin is the largest active river system both in drainage area (7-106 km2) and in freshwater volume discharged to the oceans (5.5 -102 kmVa) [1]. In terms of sediment yield as a consequence of weathering process, large amount of material originated from the upper drainage areas enters the streams of the region like suspension sediments, which can be temporarily stored or trapped in the lower drainage areas (Amazonian depression) every year through periodic floodings, instead of reaching directly the ocean. These floodlands in the Amazonian landscape ore called by varzea and occupies an enourmous area of about 60,000 km2, being a very productive land which is fertilized annuely by the flood-water. < As part of an effort to improve the knowledge concerning weathering rates in Amazonian rivers, the chemical composition of sediments and suspended matter is being assessed applying complementary analytical techniques. In the present paper the main attention is paid to the determination of some trace elements in varzea sediments by neutron activation analysis. In 1985, after reaching the peak of the annual flood (discharge of 203,000 nf.s-l in Obidos, site 16), twenty-four samples of the uppermost 20 cm of the sediments were collected, being 19 8long 2,300 km from the Amazon itself and 5 from all the major tributaries (Fig.1).

. R. Amazonas .—^ B |\23 4 5 6?V8 9 10 Il\l2 13 J4\l5 16 17 18 19

2000 Km _J I i i—i- Fig. 1. Schematic drawing of drainage area of the Amazon.

Special care has been taken to assure homogeneity in preparing the samples. Ca 200 mg of each sample were placed in polyethylene tubes and irradiated

35 together with IAEA standards in a nuclear reactor at a flux of about 5 MO12 n.cm"2.s"1 for 8 hours. Following by high resolution gamma-ray spectrometry with a germanium semiconductor, over 23 elements were determined. Analytical data showed in Fig.2 were normalized by dividing the compositions of tributaries samples by the average for the main river samples. The hypothesis that there is a difference in trace element composition of v&rzeas from various sites in the whole drainage area was tested. No significant differences in chemical composition were apparent except for Negro river in which it changed abruptly, falling out of general trend and showing distinct variations from the average, as it was expected. According to geomorphologycal studies 12), the basins of tributaries lea, Jurua, Purus and Madeira have the same sedimentary origin from Tertiary-Quaternary, while the Negro basin is related to the Crystalline basement. It has been noted that the same behaviour was achieved for macronutrients analysed in the same samples 13]. 300

200

100-1=*,

Fe Sc Hf La Co Th Fig. 2. Relative contents of some elements.

II] Kronberg, I.B.& W.S. Fyfe, SCOPE/UNEP, 55(19Q3) 215-222. 121 Sioli, H. Tropica) River: The Amazon. In: B.A. Whitton, ed. RIVER ECOLOGY, Berkeley, U.C. Press, 461 -487. [31 MartinelU, LA. Thesis, ESALQ/USP, Plrecicaba, SP (1986) 214 p.

36 QTimv ni? nnDnw TM i FTJIMP pnDPAr.p

Deng Hongmin, Li Jianraing Institute for Application of Atomic Energy, CAAS P.O. Box 5109, Beijing 10009*+, China

Boron is one of the essential trace elements in plant. It will appear in disease or toxicity when boron is keeped by plant in less than the minimum limit quantity or more than the maximum needs. Tt is quite difficult to control the necessary quantity and to analyse the element. So it is not clear perfectly to play what a role and how to transfer for the boron in plant.

The distribution of boron in pea (Pisum sativum L.), al­ falfa (Medicago sativa L.) and birdsfoot trefoil (Lotus corniculatus) were studied by use of solid state nuclear track detector (SSNTD). And the translocation of boron in pea were discussed using B as a tracer. Also boron defi­ ciency and toxicity symptoms of those three legumes, espe­ cially the effects of boron on radicle growth of pea and common sainfoin (Onobrychis viciaefolia Scop.) seedlings, were observed.

The results show that boron deficiency or toxicity severely inhibits legume growth, especially radiacle growth. Lomest leaf has the highest boron content.

Neutron-induced autoradiographic examination of boron in leaves indicates that boron contents in tip and margin are much higher than in base and center. Boron contents in veins especially in midribs of vegetative pea and alfalfa are very low, but high in veins of flowering pea» Among

37 flower tissues, ca(yx has the,highest boron content.

B tracer experiment shows that root application of boron has the highest rate of boron absorption by plant and boron applied to leaves mainly remains in the treated areas.

CI) Duval, Y., Thellier, M. J., Radioanal. Chem. 55 (2), 1980. \Z) Szabo, A. S., Isotopenpraxis, 17 (7) (1981) pp. 275 - 278. \3) Deng Hongnin et al., Research and Application of Trace- Element fertilizers, Hubei Science and Technique Fress U985.J PP. 31/+ - 32A.

38 MEASUREMENT OF FILM THICKNESS BY 14 MeV NEUTRON ACTIVATION ANALYSIS

P.M. Dighe, G.R. Pansare and V.N. Bhoraskar Department of Physics, University of Poona, Pune-411 007, India.

Thickness of individual copper, aluminium and silicon thin films deposited as single and multilayer coatings have been measured using 14 MeV neutron activation analysis . technique. Weights of aluminium films estimated with an accuracy of 1 % indicate slight deficit in the film density below thickness around 300°A. Several methods are routinely used for thickness measurement of single layer films which are however not useful for multilayer coatings. The RBS is a powerful technique for such studies however tedious calibration procedures are to be carried out and many a times the spectrum is masked with continuous energy of the backscattered He-4 ions when the first layer is thick and of high z material,,followed by low z layers. The 14 MeV neutron activation analysis technique has no such limitations. Thin films of pure aluminium, copper and silicon were deposited in clean vacuum ~ 10~6 torr on perspex and glass substrates by vapour evaporation technique, keeping area of each film close to one sq cm. Thickness of each film was measured in situ by a quartz crystal monitor and later on by stylus method. Each film on irradiation with 14 MeV neutron flux ~ 10° n/cm /sec was brought to HPGe (30 %) detector and the induced gamma ray activity was recorded in a M.C.A. The nuclear reactions used for aluminium, silicon and copper are given below respectively by expressions [1], [2] and [3].

39 27Al(n,«C)24Na, T = 15 1/2 Hrs. <5" = 125 +_ 12 mb (1) 28Si(n p)28Al, T = 2.3 ; 1/2 rain. 6" = 250 + 75 mb (2) 63 62 Cu(n,2n) Cu, T1/2 = 9.55 min. 6 = 450 + 67 mb (3) After smoothening the gamma-ray spectrum and making standard corrections, area under the photopeak was estimated. Neutron flux was measured by irradiating pure aluminium alongwith thin film sample. For calibration purpose, different thickness single layer films were deposited and the number of atoms of the element and therefore the film weight was estimated using the above procedure. For one sq cm area aluminium films, the Pig 1 shows a plot of the number of atoms versus film thickness. Such curves were also obtained for copper and silicon films. Using the estimated values of number of atoms and measured values of film area and thickness, density of aluminium films of different thickness were estimated. Samples of multilayer coatings were also analysed using the above procedure. The overall accuracies achieved in estimation of weight and thickness of film are around 1 % and 3 % respectively. The estimated values of aluminium film 3 density varied in the range 2.42 + 0.24 to 2.69 + 0.11 gm/cm in the thickness range 530°A to 2000°A respectively.

!!

0-2 0.5 07 0.9 I.I 10 (Tliouwnilsl MQQSUied lliiclaiMS (A) Fig.l'Plol ol number ol atoms versus Ihicknsss ol Isti-'cm oHiminuitn lilm.

40 USE OF 14 MeV NEUTRONS IN ANALYSIS OF EXPLOSIVE CLASS MATERIALS

P.M. Dighe, G.R. Pansare, S.G. Kulkarni and V.N. Bhoraskar Department of Physics, University of Poona, Pune-411 007, India.

Analysis of explosive and propellants is often carried out to assess their suitability for practical applications. Among other contributing factors, the type of elements and their relative concentrations are important to decide optimum power levels obtainable from given sets of explosives and their ingredients. Nitorgen and oxygen are present in various classes of explosives and propellants whereas aluminium is added to increase power of underwater explosives. Ammonium percholarate is another important compound and its concentrations can be obtained on the basis of chlorine content. It is known that propellants, specially double base and CMDB type on long storage have tendancy to undergo slow decomposition with evolution of nitrogen in the form of its oxides. As a result the value of the nitrogen to oxygen ratio deviates from the original set value which often adversely affect the properties of the propellants. There are several known methods [1-3] based on chemical analysis which can be used for estimation of concentrations of oxygen, nitrogen, aluminium and chlorine. However most of these methods are destructive, need considerable handling of materials, time consuming and carry added risk of explosion when used for

it Institute of Armament Technology, Pune-411 025, India.

41 explosive class materials. Overcoming all these difficulties, 14 MeV neutrons activation analysis technique has been successfully used in this laboraotry for analysis of several type of explosive class materials, such as torpex and dentex familir es, containing RDX, TNT, HMX, Al and wax. Some of the polymers like nitrocellulose, polymeric binders, and plastic bonded explosives were also analysed. Sample of quantity in the range 10 to 100 mg was irradiated with 14 MeV neutron flux - 10 ii/cm"/sec and the induced gamma ray activity was measured using a 3"x3" Nal(Tl) detector or HPGe (30 %) detector coupled to a 4096 channel analyser. To estimate concentrations oF. oxygen, nitrogen, aluminium and chlorine following nuclear reactions were used

16 14 0(n,p) N, T1/2 - 7-35 sec. 6 = 42 mb (1) 14 13 N(n,2n) N, T1/2 = 9-96 Min. 6" = 5.7 mb (2) 27 27 Al(n,p) Mg, T1/2 = 10 Min. <5"= 81 mb (3) 37 37 Ci(n,p) S, T1/>2 = 5.05 Min.

The experimentally obtained values of elemental concentrations are in good agreement with the theoretically expected values. In a few samples stability of explosive class materials against high temperature was also studied. The 14 MeV neutron activation analysis techique is found to be very useful in analysis of almost all kinds of explosive class materials. [1] Yimon et al., The analysis of Explosive, Pergamon Press, 1931. [2] Rigdon et al., Propellants, Explosives and Pyrotechnics, 8, 206, 1983. [3] Malone H.E. The Analysis of Rocket Propellant, Academic Press, 1976.

42 INAA OF VEINED PYROCLASTIC ROCKS FROM ABAKALIKI, LOWER BENUE TROUGH, NIGERIA.

L.A. Dim, J, Adetunji, CD. Okujeni , * S.A. Agaja and G. Gudmar Department of Physics, Department of Geology, Ahmadu Belle University, Zaria, NIGERIA. Department of Reactor Physics, Chalmers University of Technology, Gothenburg, SWEDEN.

Abstract: Elemental data on the composition of the pyroclastic rocks, Abakaliki, Nigeria are still in adequate to help in resolving the confusion (among geologists and other scientists working in the area) about the petrology and the stratigraphic position of the deposit. Thirty elements: Fe, Mg, Ca, Mn, Al, Na, Ti, K, Ba, Cr, V, Co, 'An, W, Rb, Sc, Hf, Ta, Cs, REE (La, Ce, Nd, Sm, Eu, Tb, Dy, Yb, Lu) and Th were determined in the veined pyroclastic rocks by instrumental neutron activation analysis. Data of this type especially the content of REE, their fractionation together with field observations would be of immense benefit to geologists working in the Lower Benue Trough, who have hitherto yewne.d for geochemical data that would help them in constructing petrogenetic models on the evoluation of the trough and the deposit. Comments are made on the distribution of some element and REE on this sample.

43 INVESTIGATION ON TRACE ELEMENTS IN THE CRUDE OILS AND ORGANIC MATERIALS EXTRACTED FROM SOURCE ROCKS FROM CHINA WITH INAA

Ding Zuguo*, Chai Chifang*, Fu Jiamo** and Sheng Guoying** *: Institute of High Energy Physics, Academia Sinica P. O. Box 2732, Beijing 100080, P. R. China **: Insitute of Geochemistry, Academia Sinica P. O. Box 91, Guiyang 55002, P. R. China

Compared with most of the crude oils originally formed in marine deposit environments and then distributed over continents and their shelves, the oilfields in China are mainly formed in continental deposit environments during the Tertiary period.

In order to study the correlations between the trace elements in crude oils and organic materials extracted from oil-forming source rocks and their indicative roles to petroleum formation and evolution, a combination of Soxhlet extraction, column chromatography, GC, GC-MC and INAA was taken in this work. With these methods, the samples of the crude oils or source rocks from China have been separated, step by step, to five fractions, i.e. saturated, aromatic, non-hydrocarbons, asphaltene and the insolube fraction— kerogen. All fractions but the saturated hydrocarbon were analyzed with INAA. The saturated and aromatic hydrocarbons were analyzed with GC and GC-MC to study biomarkers. In this way, we determined more than thirty trace elements in over one hundred samples from nine main oilfields in China and detected some biomarkers in the crude oils from the Jianghan oilfield in central China. The following conclusions may be drawn from our experimental results.

1. The general characteristics of trace elements in the crude oils from China The determined elements include Al, As, Au, Ba, Co, Cr, Cs, Cu, Fe, Hf, 1, lr, Mg, Mn, Mo, Na, Ni, Rb, Re, S, Sb, Sc, Se, Th, V, Zn and some of REEs in the nine main oilfields in China, i.e. Jianghan, Zhongyuan, Biyang, Shengli, Liaohe, Kalamayi, Renqiou, Dagang and Songhuajiang. The V/Ni ratios in this study are mostly between 0.001 and 0.12, much lower than those in the crude oils from other countries! see

44 Table 1 ).

Normalized to the North American Shale Composites!NASCJ for Sc, V, Cr, Mn, Fe, Co, Ni, Zn, Se and Sb, four crude oil sampler from the Jianghan oilfield show that if the crude oils are of the same origin, the trace element patterns for the crude oils are also similar with each other, which has been testified by the biomarkers.

II. The distribution of trace elements among fractions The total concentrations of trace elements in different fractions of the same sample, crude oil or organic materials extracted from source rock, decrease in the following order: asphaltene, crude oil or organic materials extracted from source rock, aromatic hydrocarbon and non-hydrocarbon.

On the other hand, the transition elements and RElis mainly exist in asphaltene, while Na, K, Al, S and halogen elements are mainly contained in aromatic hydrocarbon fraction.

I'll. The effect of geological setting on the concentration of trace elements Concentration of sulfur in the crude oils from the Jianghan oilfield is about 10% in average, much higher than that in other oilfieds. It may have been caused by the surrounding rocks with high sulfur content and anoxic environment during the oil-forming process.

Table 1. Concentrations Of V and Ni and Their Ratios in Crude Oils in China

Deposi t Places V'lppm) Ni(ppm) V/;Mi environment3

Jianghan 1.231 27.31 0.045 Continent Zhongyuan 3.678 .io.17 0.101 Continent. Shengli 1.279 62.35 0.020 Continent Liaohe 1.410 74.50 0.019 Continent Dagang 0.090 9. 71:5 0.009 Continent Songhuajiang O.iloO 3.310 .).043 Continent Biyang 0.5 i'J 24 . 11 0.H23 Continent Kalamayi 10.1 i

45 D;-TK^LL\:.\TION OF TRACE ELEMENTS IN NORMAL AND DIABETIC WHOLE BLOOD 3Y :-;.-JTF^; ACTIVATION ANALYSIS

F.A. Ei-Arori, U.E. El-3altani D?.partr.-.3nr. of Chemistry, Al'Fateh University, P.O. Box 13361, •i'ripoli-Libya- and I.A. Ashour Tajura Nuclear Research .Center, Tripoli-Libya.

The beneficial effects of some elements, as well as the toxicity of obhers co humans are well known. The levels of trace elements in livi­ ng o'_-.>-ris^s {i:i health and diseas&) depend mainly on diet and local en- viror_v..2nfc. ^IJ human' body continuously assimilates variety of elements which a.:.:: ciot-o'iy related to human health and disorder since their def­ iciency or excess induces physiological changes. Blood samples were co­ llected from Tripoli area to investigate the relationship between the levels of trace elements and diabetes. The. blood samples were lyophil- ized and irradiated with standards at Tajura Nuclear Research Center, 12 -2 -1 Tripoli, in-a neutron fl'ix of 2.5 x 10 n™ sec . For irradiation decay and counting tines, which were based on half-life of the nuclide of interest, the activated samples were counted on a Ge(Li) detector co­ upled to 4096 channel pulse height analyzer.

NAA is adequate for instrumental determination (INAA) of elements such as Br, Co, Cs, '-in, Fe, A, La, Mn, Na, $b, Sb and Zn. However, other elements of great environmental and biological interest, such as Au,Ag, As, Cr, Cd, Kg, Mo and Se, cannot be determined solely by INAA. This is 24 32 ;.viinly dua to the presence of predominant radionuclides e.g. Na, P, in the X -ray spectrum for biological samples, which mask their K-ray emission of the less abundant radionuclides. In this case selective radiochemical separations are necessary before the measurement of the activated samples (ENAA), even though the actual sensitivity may be su­ fficiently high. Radiochemical separation technique such as, ion exch- yiigs jaromatcgraphy on the organic and inorganic resin, using Dowex - 1

Al203, 3n 02, Cus and SbjOj. with different combinations, was applied.

46 A comb illation of multi-element character of tha INAA with the specific­ ity of BNAA makes it possible to gain infoniYi tion. on many elements .in each of the samples analyzed.

For INAA the preliminary results of the analysis of Co, Cr,. Hg, Pb, Sa and Zn indicated that the concentration of Zn in diabetic male subjects is lower than normal. This is expected since Zn is essential for insu­ lin activity; concentration of Cr and Se appear to be higher in diabet­ ic females as compared with diabetic males. The dependence of the ele­ ments contents on different parameters (e.g. sex, aje) is indicated.

M Speciation of arsenic in water samples

J.T. van Elteren en H.A. Das

Netherlands Energy Research Foundation P.O. Box 1 1755 ZG Petten (NH) The Netherlands

Two methods have been developed for rapid and sensitive speciation of arsenic. The first is based on sequential coprecipitation with dibenzyldithio- carbamate, followed by neutron activation analysis. The second group of procedures uses solid phase extraction of triva- lent arsenic by on-column formation of As(III)-trispyrrolidine carba­ mate.

The determination of As (HI) and As(V) in water samples by sequential coprecipitation is summarized in figure 1. It is based on the conse­ cutive coprecipitation with dibenzyldithiocarbamate (DBDTC) of As(III) and As(l'), respectively, the latter species after reduction to As(III) with a mixture of KI and thiosulphate. The precipitates are collected successively on 0.45 un» membrane filters and arsenic is quantified by neutron activation of the filters and subsequent Y-spectrometry.

Optimum conditions for the two steps of the sequential coprecipitation technique were determined using "As(III)- and '*As(V)-tracers. Under the optimized conditions some other heavy metal tracers were applied to study the selectivity of the method; of these Cd and Fe were quan­ titatively recovered and Ag and Zn partly. The accuracy of the method was checked by determination of the total arsenic concentration in some water reference materials by applying the second step of the coprecipitation technique. The values found were well within the certified ranges. The applicability of the method for speciation of arsenic in a fresh water sample is demonstrated. As(III) and As(V) could be determined with a relative standard deviation of 3 and 5 %> respectively and a detection limit of 0.02 pg S.-1 . Investigation of the behaviour of some other arsenic species like mo- nomethylarsonic acid (MMAA) and dimethylarsinic acid (DMAA) under the sequential coprecipitation technique showed that neither MMAA nor DMAA are coprecipitated in the first step; in the second step MMAA is co- precipitated at all. This implies that MMAA interferes in the deter­ mination of As(V).

Table I summarizes the results of some reference waters.

The second method is based on the preconcentration and determination . of As(III) and As(V) after preliminary reduction to the trivalent state) by using complexation-type stationary phases. These phases are

48 prepared (1) by loading a Cl8-bonded silica with the cetyltetra- methilammonium-pyrrolidinedithiocarbamate (CTA-PDC) ion-pair, or (2) by converting a strong anion-exchenge (SAX) resin frointhe quaternary ammonium form into the pyrrolidinedithiocarbamate (PDC ) form. When As(III)-containing solutions are passed through such stationary pha­ ses, the immobilized PDC yields the non-polar As(III)-trispyrrolidi- nedithiocarbamate, which is retained on the non-loaded back part of the Cl8 cartridge procedure, or on an unloaded Cl8 cartridge coupled in series with the SAX cartridge procedure (2). The retention mecha­ nism is discussed.

Parameters influencing the selective preconcentration of As(III) and As(V) have been investigated by using As-radiotracers. The amount of As(III) and As(V) in some water samples have been determined by Hydride Generation Atomic Absorption Spectrometry (HGAAS) and by Instrumental Neutron Activation Analysis (INAA).

Table II gives the recovery of 7*As(III) after preconcentration from different waters and varying volumes. For procedure 2 the remaining amount of arsenic on the SAX cartridges is given in brackets.

Table I Results for three reference waters reference found X ± S certified sample (ne e-1) (MS C"1 ) (ug e-1)

1.39 NASS-2 1.59 1.47 ±0.11 I.65 ± 0.19 1.41

1.08 CASS-1 1.08 1.03 ± 0.09 1.04 ± 0.07 0.92

0.33 SLSR-1 0.40 0.43 ± 0.11 0.55 ± 0.08 0.55

49 & Table II RECOVERIES IN % (± 2%) volume (ml) tap-water Nil canal water North Sea water procecjre 1 25 97 99 98 50 97 99 98 75 95 99 .98 1G0 81 97 97 150 3 72 78 200 2 46 50 procedure 2 25 97 (0) 96 (1) 97 (0) 50 95 (1) 95 (1) 97 (0) 75 97 (1) 95 (0) 98 (1) 100 95 (3) 96 U) 96 (1) 150 9 (2) 83 (l) 96 (2) 200 0 (2) 10 (0) 29 (1)

100 g water sample + 100 ml 1 M HNO-

1 ml 1% (w/v) mWTC solution (in MeOH) 5-10 min. FILTRATION 0.H3 lira > As{III) membrane filter

FILTRATE + 1 ml 20% (W/v) KI +

1 ml 25% Na2S20_.5H20 solution 15-20 min. REDUCED SOLUTION + 1 ml 1% (w/v) DBDTC solution (in MeOH) 5-10 min. FILTRATION 0.'I5 urn > As(V) membrane filter

Figure 1. Optimized sequential coprecipitation technique.

50 PLANETARY GAMMA-RAY SPECTROSCOPY: METHODICAL IMPROVEMENTS IKS vFTR0N ,NELASTIC SCATTERING CROSS SECTIONS1 BETWEEN 20 AND 70 MeV Peler A.J. Englert San Jose State University, San Jose, CA 95192, USA Carlos M. Castaneda and Behzad Sanii Crocker Nuclear Laboratory, University cf Califor^ DaviS| CA 95616i USA Darrel M. Drake and Robert C. Ree^ Los Alamos National Laboratory 'LCS Alamos, NM 87545, USA John C. Young California £iate university, Chico, CA 95926, USA

Gamma-rays emitted from surfaces of solar system bodies with little or no atmosphere such as asteroids, planets such as Mars, and/or moons, are used to determine the chemical composition of the upper few decimeters. Gamma-ray spectrometers for chemical analysis are important components of orbiting spacecraft in many solar system exploration programs. Gamma-rays are emitted from naturally radioactive elements. The majority of gamma-rays in galactic cosmic-ray exposed surfaces, however, are induced by nigh-energy charged particles and neutrons of the secondary hadron cascade. Both, inelastic scattering processes of the energetic neutrons as well as neutron capture reactions of the finally thermaiized neutrons contribute the majority of the analytically useful planetary gamma radiation. In principle, planetary gamma ray spectrometry can be considered as a special form of prompt charged particle and prompt neutron activation analysis [1]. One major difference to terrestrial applications of prompt activation analytical methods is the lack of direct comparison of the extended planetary surface target to a standard exposed under the same conditions [2,3]. Model calculations substitute for the lack of direct comparator methods. However, for energetic neutrons only estimated cross sections can be used in those calculations. In addition, the neutron energy spectrum at various locations in a planetary surface is a function of the abundance of effective moderators in the surface [4], and inelastic scattering cross sections over a wide range of energies are required to support analytical efforts. The lack of well known cross-sections for neutron inelastic scattering reactions in rock- forming elements does not surprise. The experimental determination of such cross sections is difficult and such data are not needed in more common applications of prompt activation analytical techniques. For a better understanding of absolute elemental abundances inelastic neutron scattering cross sections up to 150 MeV would be required.

51 In our experiments we made use of the neutron beam line of the Crocker Nuclear Laboratory cyclotron at the University of California Davis. Neutrons at this facility are nroduced by the 7Ufo,n) reaction. The neutrons are quasi-monoenergetic with 60% of the total neutron flu* districted around the maximum energy with a FWHM of 1 to 2 MeV depending on the thickness Ct the Li-target [5]. The neutron beam spot at the target site has an area of 4 cm by 8 cm. Us'iM time-of-flight techniques, neutron inelastic scattering gamma-rays at energies between 20 2.nd 70 MeV were measured. Neutron flux and energy were determined via recoil protons produced in a thin polyethylene toil upstream of the target chamber.

A plexiglass target chamber with very thin windows was attached to the end of a vacuum beam pipe and connected to a 50 cm diameter water pipe. Chamber ?nd pipe were filled with Helium to suppress gamma-ray background from, neutron interacts with air. Neutrons were stopped 8 m downstream of the target station in a concrete wan'. Targets with an area of 10 by 10 cm and a thickness of up to 1 cm were irradiated. The gamniS- radiation emitted between 100 keV and 4 MeV was recorded by two heavily shielded HpGe detectors placed 40 cm away from the target at angles of 53 and 127 degrees, respectively.

Absolute detector efficiency and gamma-ray selfabsorption in the target was experimentally determined using calibrated standard gamma-ray sources of an area of 4 by 8 cm.

Data evaluation is still in progress, but first results from the exposed Fe-target show good agreement with previous measurements of Larson (1986) [6] at neutron energies of 40 MeV or less.

The complete set of neutron inelastic cross section measurements for Fe, Si, Al, Mg, and S is in preparation. Incorporation of these cross sections in data deconvolution procedures for planetary gamma-ray spectrometry will be discussed.

[1] Englert, P.A.J, Brueckner, J., Waenke, H., J. Radioanal. Nucl. Chem., 112 (1987) 11. 2] Wormland, M.R., Clayton, C.G., J. Appl. Radiation Isotopes, 34 (1983) 71. 3] Evans, L.G., Trombka, J.I., Lapides, J.R., Jensen, D.H., IEEE Trans. Nucl. Sci., NS28 (1980) 1226. r4] Brueckner, J., Waenke, H., Reedy, R.C., J Geophys. Res., 92B4 (1987) E603. 5] Jungermann, J.A., Brady, F.P., Nucl. Instr. Meth., 89 (1970) 167. [6] Larson, D.C., Radiation Effects, 92 (1986) 71.

52 PLASMA AND TISSUE LEVELS OF SOME LANTHANIDE ELEMENTS IN THE HUMAN COLORECTAL LESIONS. ••' M.ESPOSITO, P.COLLECCHI, M.ODDONE*,H.MARTINES, H.ASTE, F.MERLO.S.MELONI? V. CARAMELLA-CRESPI0, and M.GEN0VA0. 1ST, Genova; *Dipartimento Chimica Generale Universita di Pavia;°Centro CNR per la Radiochimica e Analisi per Attivazione.Dipartimento di Chirni ca Generale, Universita di Pavia, ITALY . INTRODUCTION. Our previous studies have shown that the concentration of lanthanides (Ln) is altered both in inflammatory disease and in larynge al carcinoma /l/.suggesting an involvement of the Ln in a patophysiologi^ cal response. Although Ln are known to interact with a number of tissue components - either inhibiting or mimicking the effect of Ca^+ - their specific biological role is not clearly understood. The principal purpose of this study was to evaluate the levels of lanthanum (LaJ, cerium (.Ce), ytterbium (Yb)s neodymium (Nd) and europium (Eu) in plasma, neoplastic and fiiacrospically normal tissue of patients with colorectal diseases. MATERIALS and METHODS Forthy-one male patients (pts), aged 42-81 years, who underwent colonscopy were classified into the following groups, a£ cording to the histological diagnosis: Adenocarcinoma (ADK) ( N.=17 ), Adenomatous polyps (N.= 9 ), Healthy (Control) subjects ( N.=15 ). Blood and tissue samples were collected as previously described and Ln were determined by radiochemical neutron activation analysis HI. Statistical significance was tested at a p<0.01 by means of t test,unpai. red case. RESULTS and DISCUSSION Table 1 shows mean plasma Ln concentration in control, pts with adenoma or ADK. Mean plasma concentration of La, Yb and Eu were significantly higher in both adenoma and ADK groups than in the control group. No significant difference was observed in Ln concen tration except when La and Yb mean plasma levels of the adenomatous po lyp and ADK were compared. TABLE 1 N.pts La" Ce00 Yb°° Nd°° Eu°° Control 19 3.44+0.50 35.37+3.95 1.93+0.48 35.49+3.22 0.91+0.03 Adenomatous 9 28.15+3.74 30.47+10.6 2.99+0.58 30.92+3.51 7.88+0.91

polyR,,-,'.- p<* 0.0005 0.05 0.0005 0.0025 0.0005

ADK 17 31.45+2.78 32.64+4.20 4.01+0.90 32.86+5.23 8.76+1.32 p<* 0.0005 0.025 0.0005 0.0005 0.0005

?<° 0.01 NS 0.005 NS NS 0"Values expressed as ng/ml plasma, mean+SD {"compared with healthy subjects and ° with adenoma.

Ln concentrations in ADK, adenoma and their adiacent macroscopically

; / i „io', "measured in normal tissue are reported in Table 2. Ln tissue levels 1. _ ^^ ADK and adenomatous polyps were found to be constantly higher measured in adjacent normal tissues TABLE 2 TISSUE- La Ce Yb Nd Eu 6+0.8 Non-malignant 37+4.9 36+4.7 4.2+0.8 33+3.7 ADK 59+9.3 55+5.0 6.0+0.9 55+6.4 10+1.0 Normal 32+4.5 32+5.2 5.9+2.7 32+2.4 5.9+1.8 Adenomatous polyp 68+7.9 60+9.5 8.0+2.4 61+7.4 11+2.3

*r*g/g dry wt, meanjhSD; each patient acting as his own control.

Biochemical properties of Ln depen'd on their effects on some enzymatic system ;and cm their ability to interact with Ca-+ receptors. Epidemiolp_ gfical studies/2/ suggest that calcium could have a protective role liluring colomectall carcinogenesis, inducing a more quiescent proliferate we st*:e in mormal epithelial cells. Our finding show an increasing iconcerttratSon of plasmatic and mucosal Ln from healthy subjects to adeno imatoias pol^yp and ADK pts.. One possible explanation of the high concan_ ftration of ;Ln .in ADK '.may ,be the high proportion of necrotic cells usua_l ly present

Fang Hong, Feng Xizhang, Chai Chifang Institute of High Energy Physics, Academia Sinica. P.O. Box 2732, Beijing 100080, China

Carbonaceous chondrite matrix is a kind of matter with abundant iron, mie grains and dark colour,and is considered to be formed in low temperature and oxidation conditions of the solar nebular . It is difficult to get pure matrix sample from choudrite. simply because of mixing chondrules and mineral debris in it. Although electron microprobe analysis in a width beam and many points can give mean matrix chemical composition, it is impossible to get the trace element feature of the matrix.

We studied the matrix chemical compositions of the Ningqiang choudrite.the first carboncarous chondrite of China, by instrument neutron activation analysis .The matrix sample NQ- J-2 was produced by sifting* the Ningqiang meteorite powder which was not ground. Its major compositions analysed by INAA are: Na20 0.52%, MgO 1G.S7%, FcO 36.16%, Cr203 0.54%, A1203 3.60%. MnO 0.14%, NiO 1.39%, which are very close to the results ** by EMA [l], so the. NQ-.T-2 can be considered as a representing sample of mean matrix of Ningqiang ; Another matrix sample NQ-J-3 dug from a limited small area of the Ningqiang sample, by a stainless needle was also analysed by INAA.

Table 1. shows the. trace element compositions of the Ningqiang matrix from INAA. The result of the Ningqiang whole rock (named NQ) was also listed for comparison.

From these results, the following conclusions can be drawn : 1) the Ningqiang matrix (NQ-.T-2) has slightly more light rare earth elements and iron than the whole rock, and other elements do not show obvious difference in the both samples: 2)the local matrix (NQ-J-3) is very rich in iron (up to 3S wt%).and depleted in refractory lithophile elements Sc,REE related to the whole rock: 3) the abundances of refractory siderophile element Ir are similar in the three samples.

Our work indicates that the trace element compositions in the Ningqiang matrix and whole rock have not obvious difference, but the composition difference between .the mean and local matrix is present. So the. distribution of trace elements in the

55 Nhigqiang chondrite matrix is not homogeneous.

Tab. 1 The trace element compositions of the Ningqiang matrix and whole rock by INAA (ppm or wt%)#

NQ-.I-2 NQ-.1-3 NQ Ir 0.5C6±0.032 0.567±0.015 0.693±0.054 La 0.98±0.29 <0.54 0.44±0.12 Ce <0.G6 Sin 0.61±0.06 0.1S±0.07 0.30±0.02 Eu <0.21 <0.7S 0.50±0.02 Yb 0.73±0.53 <0.18 0.55±0.39 Tm 0.72±0.53 Lu <0.20 So 11.1±0.2 C.OdbO.l 10.7±0.5 Aii 0.130±0.009 0.132±0.01S 0.159±0.010 Fe% 28.1±0.4 38.0±1.0 24.4±0.4 Co G46±6 745±5 612±39 Ni% 1.09±0.15 1.43±0.03 1.49±0.06 Cr 3G70±33 3430±161 3590±60 As 1.31±0.43 <0.74 2.02±0.29 Se 12.0±10.4 12.0±2.3 14.G±2.7 Sb 4.5±2.5 Zu 83.1±56.S 251 ±24 135.2

* Errors are statistical counting deviation (90% confidence level).

* The sieve hole is 0.050 mm in size .

** The results are as follows: Na20 1.2±1.3%, MgO 14.8±1.7%, FeO 36.3±4.2%, Cr203 0.39±0.17%, A1203 4.1±1.1%, MnO 0.24±0.04%, NiO 0.23±0.21%.

[1] Rubin A.E., Daode Wang, Kalleemeyn G.W., and Wasson J.T. (198S) Metepritics V.23, P.13-23.

56 PROGRESS IN MEASURING THE IMPURITY CONTENTS IN A BaE, CRYSTAL USING THE PIXE ANALYSIS

Feng Songlin, Zhong Ming, Ren Minqin, Liu Nianqin Institute of High Energy Physics, Academia Sinica, Beijing 100080, CHINA

Both fast and slow components of light pulse possessed by BaF2 crystal have been observed by Zheng Zhipeng,et al. The magnitude of light yield is as large as that of BGO. A high time resolution was obtained as the fast components was used to measure time. The energy resolution was higher than that of BGO. In addition . a very good efficiency for r-ray detection due to a high density of 4.9gram/cm, the emitting light easily pass through it and then go into the window of a photornulti- plier because of its index of refraction of 1.56. It combines such a lot of advantage to make scientists widely interested in it.

Only phosphorescence, as we know, emitted from a normal inorganic crystal such as NaI(Tl),CsI(Tl), ZnS(Tl). The emission mechanism is following: the proba­ bility that electrons, which in conduction zone excited from valence band as a scintillating crystal is radiated by charged particle, deexcited directly to ground state is extremely low. The probability that electrons,after having kept in the trap formed from the impurities for a while (metastable state), and then went back to ground state followed by emitting the photon, is extremely high. Therefore, inor­ ganic scintillating crystal only radiates one ray- phosphorescence ( decay time of light t=0.1-l. us). Why two components of light pulse simultaneously are emit­ ted from BaF which belong to inorganic crystal, and how is the relation between the proportion of two components and the impurities of BaF2 crystal, that is our research purpose.

First we should measure, the impurities in BaF:crystal by PIXE analysis technology , and then study whether the proportion two components depend on the impurities contents. It is difficult to prepare a thin target of BaFa crystal, due to its difficulty to be dissolved. After having grinned ,BaF2 power was digested for two hours at 200*C,using pressure bomb with ultrapure HC1. we could added some redistilled water in it and fully stir it to transparent liquid.lt might be made a well thin target within two hours,otherwise,it will crystallize or precipitate again.

We analyzed difnrent positions in a BaF2 crystal, BaFjcrstal with mixing La and

57 Ba^, ir.-y.i il-<[•• A i lita.'ivf in<-n:-.meiueiit was performed in our laboratory. the •"\\Vi.-rii:ieiif al i-.--.silt - -I'.ou-.ni us that BaF>crystal contains impurity clrunmt-s in tiic ny:\}?x and 1-^v;••• r-?s~ ;.•-• sr;niih*autly di&ivnt. Tlieiv are the high i*cuuTi»trafious of soiiii' i»;i-'«'ijciii"-i in ri: ..;:>; ];;\-- [»,-.-.itioa. Thi'iv ciHicrtitratioiis in the midili.1 nnd !'.!•-' ui>;.<-r i\*!.-i .u"- i:••.-.• .'...." Ic-s- fljaii one iu th." inwvv part, but also is rhs- V>:\T , i n^M^rial-. :v- ra.- ;-- .>\ii:i; ui .-rvsr-I hau* an v-ii«"'--c of purifk'atioii on the on-vial materia],. Ti:o .i;<-tl.;.\i i-. ii-^j/t.-..' of it ami to pv^-MA- the PIXE thin target is :i:viiiabb-. XL-.- ,-h-t;-;i»:s:l:.-i o/ the v.r.pnrifie.s ia D.:F. cry-tai «vill be atudied by

All ri:i> work i- in proy-v-,-.

53 USE THE HEfflQD OF ACTIVATION RADIOGRAPHY FOR GEOLOGICAL AND GBXiE- HICAL INVESTIGATION,

E S, Fiitsiyan Institute of Nuclear Hiisics, Uzbek AKademy of Sciences, Tashkent, USSR

The study of the elemental composition of local microinclusions in the objects of interest acquires more importance in the present day analytical practice. Radiography in its several different modification appears to be ens jof the perspective methods of local.analysis used in geological practice. In applying this- method to determine the local concentration;; of elements an activated ;rflicrosection. is placed together with the irradiated standard-on the appropriate photoaailsion that serves as a detector of the .induced radiation.- The exposed emulsion photoblackening- density is functionally- related to the-amount of element in the sample region adjancend to the detector'. In order -to justify, the. application of neutron-activation autoradiography for the element distribution analysis the main factors were evaluated that influence the conditions of selective autoradio- gram obtaining, i, e., resolution, detection limit optimim modrs of irradiation, exposure and.photoei-posure of a saqpi?. Such factors as sample exposure duration, photcaimlsion development time, the distance between the contacting sample and photoaaterial, photoemulsion type (the size of silver halogenide grains and emulsion layer thi &ness ) influence the radiography resolution at a certain radiation energy in a sample. In order to .analyse further a radiographic image one should study the distribution of optical density of the exposed and treated photoemulsion. The size, shape and localisation of the ; inclusion studied maybe determined applying photcrcetry for the analysis of the optical density distribution radiograms. ;

59 The data obtained allowed to find the optimum ways to select photomaterial, to prepare sarnies for analysis, to provide the exposure conditions suitable for each particular problem HicrcjhotanBtry of the radiograms obtained and the comparison of the ex­ tinction values with the mlun standards allow the quan­ The changes in photoblackening size titative characterization depending on the distance between of the element distribu­ a sample and photcoaterial for three tion in a section. different.emulsion: I. X-ray films The intensity of photoe- FM-I- the average diameter of non-de­ mulsion blackening over veloped grains of silver halogenide is visible metal with a 1.3 r&rn, emulsion thickness is 15-IS irhm; Known standard may be 2 PT-I id s 0. &km and 1 =I5aKm) used as an internal stan­ g era dard Besides, special 3. film "Micrat"-300 (d = 0.5 nfcm reference standards were andl =5-7nkm). g elaborated that model em the ratri:: studied in t??na of exposition as veil as structure. Radiographic ssthods deve­ loped allow to determine the distribution of Lxre than 20 elements with the local detection limit of (10 -10 * }&m' and the reso­ lution of 50-100 rrian, The application of the r^tneds enumerated fear- the local cemposit investigation in geology and minerology resul­ ted in ths reliable data on the element distribution laws in mine­ rals, ore samples and enclosing rock samples.

60 PROVENANCE STUDIES OF ANCIENT ETRUSCAN MARBLES BY NEUTRON ACTIVATION ANALYSIS' AND DATA REDUCTION Genova N. , Oddone M. , Meloni S. , Mello E. , £ OO OO Caramella Crespi V. , Arias C. , Buonamici M. * Centro CNR per la Radiochimica e l'Analisi per Attivazione, Dipartimento di Chimica Generale, Univer­ sita di Pavia, Pavia (Italy). 0 Dipartimento di Chimica Generale, Universita di Pavia, Pavia (Italy). + Syremont - Istituto Donegani, Novara (Italy) . 00 Dipartimento di Scienze Archeologiche, Universita di Pisa, Pisa (Italy). The identification of provenance of marbles used in ancient architecture and sculpture is quite important for archaeologists and art historians . The discovery of ancient pathways of trading networks, indirect dating of artifacts and the location of sources of prime matter (mines,quarries) and of manufacture workshops, are usually the aims of provenance studies. The development of a trace element fingerprint, as obtained by trace element determination and data reduction, has been successfully applied to clear out correlations and similarities between marble artifacts and the most important quarries of Greece, Turkey and Italy, namely Aphrodisias, Paros, Pentheli, Naxos, Denizli, Marmara and Carrara. Of course highly reliable analytical techniques and a large number of analytical data' are needed. The use of neutron activation analysis is mostly based on some peculiar qualities such as higly sensitivity, good precision and undisputed accuracy of its results. In the present paper instrumental neutron activation analysis was applied to the determination of a number of trace elements, mostly hydromagmatic and rare-earth elements, in ancient Etruscan white marble specimens, and in representative sample of the Carrara quarry of Italy. Archaeological marble artifacts were obtained from archictetural structures and statues found in well know settlements of Etruscan age, such as those in Volterra(Tuscany). Marble samples of about 1-2 g were ground, powdered (greater than 100 mesh) and homogeneized. Randomly collected subsamples in the weight range 0.1-1 g were then submitted to homogeneity test. Usually 0.5 g of marble sample were inserted into

61 polyethylene vials and irradiated together with references standards. The latter were the U.S.G.S. standard rocks G-l and BCR-1, the marble standard M.C.G. (Marble Carrara Ghent) and a synthetic standard prepared by adding to pure calcium carbonate know amounts to the investigated elements. Irradiations were carried out for 60 hours in the 250 Kw Triga Mark II reactor of the University of Pavia at a thermal flux of about 1 x 1012 n cm"2 s"1 Induced radioactivity was measured by gamma ray spectrometry using a Ge detector coupled to an analyzer- computer system. The following trace elements were determined: Sc, Cr, Co, Rb, Sb, Cs, Ba, La, Ce, Sm, Eu, Gd, Ho, Tm, Yb, Lu, Hf, Th and U. The trace elements abundances are reported and discussed.Data are given as the average of three or more indipendent determinations. Average precision is about 9%, ranging from 5 to 18%. All possible interferences in the gamma ray spectrometry were considered and checked; matrix interferences were considered as well. A comparison of the trace elements content found in the standard materials G-l,BCR-1 and M.C.G. with reference values reported in the litterature, indicates a quite good agreement, thus confirming the well known accuracy of neutron activation analysis. The variance analysis carried out on samples used for homogeneity tests, taken as an evaluation- of sample variability due to sampling, provides evidence that sample aliquots of 400 mg or greater are quite homogeneous and representative of the investigated marble sample. All the trace elements abundance data have been used for a computer assisted data reduction procedure. Data were first normalized by log transform and autoscaled to overcome the problem of large differences in the relative magnitudes of measured abundances. A new set of data was thus obtained having a mean of zero and a variance of one. •The new data set was submitted to a hierarchical cluster analysis procedure to find similarities among the investigated objects. The final dendrogram clearly indicates that most of the examined archaeological white marble artifacts had been manifactured by using white marble taken from Carrara quarry. This finding confirms the suggestion based on historical and petrographic data. The white marble quarries in Carrara had been exploited since Roman times, and the white marble was exported all over the ancient world. The conclusions of this paper considerably backdate the exploitation by the Etruscans of the most important Italian white marble quarry.

62 SEPARATION OF TECHNETIUM FROM DISSOLVED RESIDUES OF IRRADIATED NUCLEAR FUEL

H.Ghafou'rian, Sameh A. Ali, H.J.Ache Institut fiir Radiochemie Kernforschungszentrum Karlsruhe 7500 Karlsruhe

During the nuclear fuel reprocessing significant amounts of nonsoluble residues are generated. Elements such as actinides, noble metals, molybdenum and technetium present more than 99% of its content. A new extraction chromatographic process for the separation of technetium and the noble metals ruthenium and palladium using diethylthiourea (sym.) as a reduction agent for the TCO4- and formation of noble metal complexes is developed. The resulting compounds can be quantitatively separated from each other by filtration of the unsoluble palladium diethylthiourea complex and retention of the Tc02+ and Ru(NO.-DETU species on the cationic exchanger AG50W-X2. The detailed results of the noble metal separation experiments were published 1989 on the second Karlsruhe international conference on analytical chemistry in nuclear technology. The main topics of this publication will be the separation process of technetium, which presents about 7% of the residue. Basic photometric studies of the diethylthiourea reduction behaviour as well as comparable data of dynamic experiments under rele.^nt process condition in presence of the mentioned accompanying nuclides will be presented and results of the concepted installation flowsheet discussed.

63 MEASUREMENT OF PROTON-INDUCED PROMPT LOW EN­ ERGY PHOTONS BY HIGH RESOLUTION SPECTROMETRY: THE ANALYSIS OF LANTHANIDES

Dherendra Gihwala; Lotter Geoffrey Lackay School of Science, Peninsula Technikon P 0 Box 1906, Bellville, 7535 South Africa

Max Peisach National Accelerator Centre P O Box 72, FAURE, 7131 South Africa

The use of proton-induced prompt gamma-ray spectrometry as a rapid and simple analytical technique has been well established but most of the applications are confined to the use of relatively high en­ ergy gamma-rays. Since most analysts rely on the use of large Ge(Li) or intrinsic germanium detectors, which have a resolution of some­ what more than 1 KeV, separation of individual gamma-rays is not possible where there exists an appreciable concentration of gamma- rays over a short spectral region, such as in the case for photons below 200 KeV. At present this energy region, which is best served by thin intrinsic germanium detectors, has not been extensively ex­ ploited by analysts. In this study the analytical significance of the photons in this energy region was investigated for the determination of lanthanides.

Although there is a vast amount of literature on the decay of the excited state of atoms and nuclei by photon emission, most of the

64 information was accumulated under conditions that make compari­ son of the X-ray and gamma-ray intensities from different elements in a single matrix, difficult. For analytical purposes, therefore, it was necessary to compile data obtained under fixed experimental conditions. In order to establish optimal conditions for analytical sensitivity and to evaluate the extent of possible inter-element in­ terferences it was necessary to study all the lanthanides bombarded with protons over a wide range of energies.

The sensitivity of the analysis is determined not only by the yield but also by the background against which the photopeak has to be mea­ sured. The detection limit of approximately three times the standard deviation of the background in the spectrum obtained from targets of the oxides, was used as a measure of the sensitivity. In a thick target this value expresses the interference-free detection limit of the element. In terms of the above definition, sensitivities and absolute yields were calculated from gamma-rays and X-rays produced under bombardment with protons from 1.8 to 5.S MeV in steps of 0.2 meV. Excitation functions are reported over this proton energy range, for those radiation which have analytical significance.

Replicate analyses on analysed standard material showed that the relative standard error for the determination of La, Ce and Nd was about 3%, while the sensitivity was of the order of 100 j^g.g-1 for analyses lasting 20 minutes with protons of 4.5 MeV.

[1] Ishii, K., Valladon, S., Sastri, S. and deBrun, J.L. Nucl. In- strum. Meth. 153(1987)503-507.

65 DETERMINATION OF Ko-FACTORS OF SHORT-LIVED NUCLIDES (Tl/i 1 MIIM. ) BY THERMAL NEUTRON ACTIVATION TECHNIQUE

Hi en P. 2., Mai T.K., Quang T.X., Loc N.V., Thuy T.N. National Institute for Atomic Energy Nuclear Research Institute;, Dal at, Vietnam

In the Ko-stadardization technique in reactor neutron acti­ vation analysis (RNAA) the concentration of any element in the sample is determined by conventional activation analysis formula containing a "composite" nuclear parameter Ko,Au de­ fined as C1I ^ M* e e0 x Ko,Au = M 9* G? X* where M -atomic mass of the element to be analysed, Q -isotopic abundance of the target nuclid, }f -absolute in- tencity of the measured gamma ray, 6^ -thermal neutron cross section ait a neutron velocity of 2200 rn/s. The Ko,Au-factors were determined experimentally by co-irradiating the element of interest and the Au-cornparator in the reactor., The results for more 70 nuclides with Tl/2>2 ruin, have been compiled in Ref „ C2, 33.

As in our previos work [41 the Ko, Au-f actors were determined with "pure" thermal neutron in the reactor thermal column. Beside the advantage of eliminating the possible interference from nuclear reactions induced by fast neutrons. In this case the experimental results are not -influenced by the error of many factors such as neutron spectrum parameters, thermal neutron cross section 61 - resonance integral Io etc. o At the irradiation position in the thermal column of our reactor the thermal -to-epithermal flux ratio f~

The experiments were carried out by using a pneumatic trasfer system installed in the thermal column of the Dal at nuclear reactor. The garnrna spectrometer consists of 70 crn3 Hp-G'e detector and 4I< analyser coupled to PC-computer.

In order to apply the Ko-standardistation method in rapid RMAA it is necessary to determine the Ko,Au-factors of short lived nuclides,, This is the aim of this work, where the Ko., Au-f actors of 11 nuclides with Tl/2< 1 rnin. have been measured. The obtained results are presented in table 1 along

66 wit;-) the dat;i ca1ci.nat.--jc! by using the nuclear data compiled in [53.

The experimental error (about 3X) was mainly induced from the counting statistics and error of the approximated detector efficiency curve. Data in table .1. shows very good agreement between calculated and experimental results, • Howere in the practice of rapit NAA the experimental !

Tab"! e 1 :i Exper i mental Ko, Au- factors

3 Nuclides ;: T1/2(S)J EU

ri] Si morn ts A.,&e Corte F» , Moen-i L„ , De Wisp el aere ::., , E'lai A„ , Hosts. J. . -J. Radi anal. Cham. , SO (.1930) , [21 i'ioens i , I>e Corte F, , De Wisoelaare A... Hi.-ts J,., Simonit". A.., E'iek A,., Szsbo S„ .. J.. F..-:i :JV:-M;-: :s"i . Chetfi. , 82 a932) P. 385,, [3] Jovanovic 3,, I-'e Corte F„ , MoeJ-iS 1-... . Simon its A« •. Ho .it .e J, J. Radioanal»Cham., 82 (1984) p.379. [4J Hi an P.2„:, Mai T.K„:, Quang T., X. . Thuy TJ\|. . .J. Radioa:-**! , Nucl.Chem., Letters 105(6) (193!:.) p.351. E5] riughabghab S„P., Divadeenarn M. , Hoi den N.E., Neutron Cross 8ections;, Vol.1., Academic Press, INC (1984).

67 ANALYSIS OF IRON METEORITES BY INSTRUMENTAL NEUTRON ACTIVATION WITH A SLOWPOKE REACTOR

J. Holzbecher and D^ E^ Ryan SLOWPOKE Facility, Dalhousie University Halifax, N. S., Canada, B3H 4J1

R. R. Brooks Department of Chemistry and Biochemistry Massey University Palmerston North, New Zealand

In order to devise new methods of chemical classification of iron meteorites - as a refinement of Professor John Wasson's original work [1] - a comprehensive analysis programme has been initiated. The programme involves neutron activation analysis at Dalhousie University; inductively coupled plasma-mass spectrometry (ICP-MS) at the Geological Survey of Canada, Ottawa; mineralogical studies at William Rainey Harper College, Palatine, IL, USA; ICP, graphite furnace, and hydride generatioii atomic absorption spectrometry at Massey University. Analysis of 6 specimens of each of the 14 classes recognized by Professor Wasson are contemplated. This abstract summarizes the experiences in the direct neutron activation analysis of nearly 100 iron meteorites for rhodium, iridium, osmium and gold.

At the concentration levels encountered in iron meteorites Rh, Os, Ir, Au, in addition to As and Co, can be readily quantified by direct, instrumental neutron activation analysis thus avoiding more commonly used time - consuming radiochemical separations. Two irradiation, decay and counting time schemes were used:

1) t. =5 min, t, = 1 min, t = 5 min ,

Samples were irradiated in a Cd-shielded site and counted with an LEP detector; the epithermal irradiation decreases the production of mCo (main activity) much more than that of ^tfi. The LEP detector is advantageous because of the low energies of both nuclides, i.e., 51.5 keV for Rh and 58.6 keV for Co respectively. This rhodium 104m nuclide has not been widely used for rhodium determination in the past because of the self-absorption of its low energy gamma-rays in the sample matrix; the extent of self-absorption is dependent on matrix composition and energy [2] and this is difficult to correct. A simple correction method was devised by taking advantage of the close energies of Rh and finCo. The cobalt content of the meteorite sample is determined via Co after a long irradiation (high energy Co gamma-rays do not suffer from significant self-absorption). The cobalt content is also calculated using Co and the ratio of these two results, which represents the attenuation in the sample matrix, is

68 then used to correct the rhodium results assuming the,-self-absorption is essentially the same at the respective Rh and Co energies.

2) t = 7 h, 2 - 3 d, t = 2 h ± c The irradiation in a thermal flux under these conditions enables determination of Os^Ir, Au, As and Co using their following nuclides: Os (129 keV), Ir (317 keV, 468 keV), Au (412 keV), As (559 keV) and &UCo (1173 keV, 1332 keV).

A comparison of the results obtained by the analysis of untreated samples with fire assay collection into lead buttons is shown in the table below. The lead beads from 4 different meteorites and beads of a standard (SARM 7 from South Africa) were provided by International Nickel, Ontario Division, Canada. Corrections for variations in the weight of lead buttons were necessary only for rhodium because of self absorption at the low energy-of its nuclide. • -

Comparison of lead bead and direct analysis results

Meteorite Ir (UR/S) Rh (ug/g) Au (ug/sO bead direct bead direct bead direct

Toluca 2.2 2.2 0.9 1.3 1.5 2.0 North Chile 2.5 2.7 2.5 2.8 0.5 0.6 Mundrabilla 0.8 0.8 1.1 1.6 1.5 1.8 Henbury 11.2 11.0 2.3 2.1 0.5 0.5

The agreement in the iridium results is particularly noteworthy. Our value of 11.2 ug/g Ir for Henbury is reasonably close to the 13 ug/g given by Wasson [1]; the 2.3 ug/g reported by Nichiporuk and Brown [3] is clearly erroneous.

Data for all meteorites analyzed will be availabLe at the conference.

[1] Wasson, J.T., Meteorites, Springer Verlag, New York (1974) 316 pp.

[2] Holzbecher, J. and Ryan, D.E., Evaluation of Some X-rays and Low Energy Gamma-rays in Instrumental Neutron Activation Analysis, J. Radioanal. Chem., Articles, 102 (1986) 507-513.

[3] Nichiporuk, W. and Brown, H., The Distribution of Platinum and Palladium Metals in Iron Meteorites and in the Metal Phase of Ordinary Chondrites, J. Geochem. Res., 70 (1965) 459-470.

69 Multielement Analyses of Blood and Serum Samples of Diabetic Persons by Instrumental Neutron Activation Analysis

P. Ha Neutron Activation Laboratory, NW13-263 Dept. of Earth Atmospheric & Planetary Sciences Massachusetts Institute of Technology Cambridge, Ma, U. S. A. 02139 Trace element studies of human blood and serum are of multifold interest *»2t The effect of variation of trace elements in the blood of diabetic persons under medication is of special interest. In the present work, a pilot study was conducted in this direction. Multielement analyses of blood and serum samples of diabetic persons were carried out by nondestructive instrumental neutron activation analysis. Gamma ray spectrometry consisting of Ge detectors was used for the identification and estimation of concentrations of elements. Initial results of about 11 elements are reported and compared with the literature values of human blood, and serum samples of non-diabetic persons.

One blood and 4 serum samples of different diabetic persons under medication were collected and freeze dried. The dry masses, each of about 50 mg, along with the NBS 1577 (Bovine Liver) and 1633a (Fly Ash) standards were put in clean polyethylene ials and irradiated in the MITRII reactor at a flux of 4x10*2 n/cm2/s, for 12 h . The samples were counted sequentially for 3 h and 12 h or more on the computerised gamma spectrometric sytem^ consisting of Ge and Ge(Li) (60cc and 80 cc, 10% and 18% efficiency respectively, 1.8 keV resolution at 1332 keV for both) detectors after a delay of 4 d, 8 d, 15 d and 30 d.

The concentrations of different elements in the samples together with the literature values^ are given in table 1. Na in general seems to be higher than the normal values for the blood and serum. Even though Fe in blood is within the range of the normal value, the Fe in serum is consistently higher than the values of normal serum. The analysis of the blank vial showed no significant gamma activity. Since prior precautions were taken in

70 sample collection and preparation, the higher Na concentrations may be attributed to diet, medication or such factors. However, analyses of more samples need to be done as this is only a pilot study. The serum may be contaminated by the RBC content of the blood, which may result in the increase of the Fe concentrations. For determining elements like I, CI and Mn an irraddiation of 1 h with a delay of about 6 h or less has to be conducted. The present study is found to be satisfactory in doing mutielement analyses. Except for Na and Fe, the concentrations of the other elements determined in blood and serum samples of diabetic persons (under study) seem to be in the range of the concentrations of the elements in those of the non-diabetic persons.

[l]Zhuk,L.L, Kist,A.A., Mikholskaya.I.N., Osinoskaya,N.S., Tillayaev,T. Tursunbayev,S.I., Agzamova,S.V., J. Radioanal. Nucl. Chem 120(1988)369-377 [2] Lavi.N., Alfassi.Z.B., J. Radioanal. Nucl. Chem. Lett. 126(1988)361-374 [3] Ila.P., Frey,F.A., Atomkern Energie Kerntechnik Supplement to 44(1984)710-716 [4] Iyengar,G.V., Colmer.W.E., Bowen.H.J.M., The elemental composition of human tissues and body fluids, Verlag Chemie Weinheim 1978

Table 1: Concentrations of elements in blood and serum (100 ml) of diabetic persons

Element Blood Ref. [4] Serum 1 Serum 2 Serum 3 Serum 4 Ref. [4]

Br mg 255+33 130-810 545+50 480+45 ND 450+40 310-670 Co ug 1.4+.1 NA .89+.01 .98+.02 .30+.01 1.07+.02 NA Cr ug 20+3 .65-11 10+1 9+1 ND 10+1 .014-19 Fe mg 39+6 30-53 .65+.06 .77+.08 ND .74+07 .07-.13 K mg 158+5 145-192 29+5 16+3 15+3 33+7 14-21 Na mg 285+3 170-205 378+4 372+4 336+4 438+5 300-330 Rb ug 205+2 120-600 37±5 31+3 .99±J)2 ND 8-39 Sb ug .45+. 17 NA .30±.18 .20+. 12 16+2 ND NA Sc ug .6+.02 NA .20+J)l .22+.01 .44+.26 .30+.01 NA Th ug 4+.8 NA ND 1.7+.4 ND ND NA Zn ug 673±55 480-930 193+1 269+22 ND 83+7 79-170

NA - Not Available , ND - Not Detected'

71 DETERMINATION OF SELENIUM AND OTHER ELEMENTS IN HUMAN COLON TISSUE BY INAA; COMPARISON WITH RESULTS OBTAINED BY XRF METHOD.

T. Izsk-Biran, M. Mantel, N. Lavy, 0. Even and C. Shenberg. Soreq Nuclear Research Center Yavne 70600, Israel

The important role of selenium and other elements In human diseases, especially in its correlation to cancer, has been well established. Diminished blood Se levels have been associated with increased risk of gastrointestinal cancer in man.

In the present work an attempt was made to determine the level of Se and few other elements in healthy colon tissue of colon cancer patients as a first step towards a comparison study of elemental content of healthy and cancerous colon tissue of these patients.

Healthy colon tissue, obtained from cancer patients (from the Elias Sourasky Medical Centre, Tel-Aviv), were analyzed by INAA and XRF methods.

INAA Se was determined by measuring the ^-rays emitted from two different selenium isotopes obtained by the (n,>) reaction: 77"Se (162 keV, 17.5 s) and 7SSe (264 keV, 121 d). For the measurement of 77"Se the samples were irradiated for 30 s and counted for 60 s after 15 s delay. . For 7SSe the samples were irradiated for 5 h and counted for 10 h after a 10 days cooling time.Co (60Co, 1332 keV, 5.27 y) and Rb (B0Rb, 1076 keV, 18.7 d) were determined simultaneously with the long lived isotope of Se {'sSe). For determination of Mn (ssMn, 847 keV, 2.58 h) and Br (80Br, 616 keV, 17.4 min) an additional irradiation of 5 min. was performed. All the irradiations were carried out in the pneumatic tube or the core of the IRR-1 reactor at the Soreq Nuclear Research Centre, at a thermal neutron flux of 3x10'2 and 2.5x10'3 n.cm"*.sec"', respectively. The counting assembly consists of a 100 cm3 Ge(Li) detector connected to a Tracor-Northern TN-1750 multichannel analyzer, (FWHM 2.2 keV for 1332 keV). The sample weight was 200-300 mg each (wet weight).

72 ML The same samples were analyzed by XRF method. The system used is based on the excitation with a Ho X-ray tube With an optical point focus of 0.4 x 0.8 cm. The SeKa X-rays (11.2 keV) were detected and measured by Si(Li) detector of 25 mm' area, (FWHM 160 eV for 6.4 keV. FeKa) coupled to a 4096 multichannel analyzeer, TN-5400. (Tracor Northern). A rotating sample holder used in this system allowed the achievement of high homogeneity of the sample irradiation by the Mo X-rays. The samples of 50-100 mg each (wet weight) were counted for 100 s and the characteristic X-ray peak integrated.

The results obtained by the INAA and XRF methods are given in the Table. As can be seen a good agreement was achieved for Se and Rb.

In conclusion, the INAA and XRF methods are complementary and therefore a larger number of elements can be determined and the results obtained by the two methods can be compared.

Table Determination of Se, K, Hn, Co, Cu, Zn. Pb, Dr and Pb In colon tlB3ue by INAA and XRF''

Method Elemental levels in \>g/g wet weight

Se K Mn CO Cu Zn Pb Br Rb

INAA'' 0.8±0.1 - 0.9510.20 - - - - 1.211.2 - INXA" 0.6+.0.1 - - 0.0310.02 - - - - 2.5+0.5 XRr4' 0.610.1 1705±281 2.5+0.8 18.6*2.8 0.36±0.18 5.210.8 2.8+0.4

1) Mean values of 3 different samples ± S.D. 2) Irradiation tine : 30 s for Se, 5 mln for Mn and Br. 3) Irradiation time 5 h. 4) Counting tine 100 a.

73 RNAA OF ULTRA-TRACE Ir IN PRECAMBRIAN-CAMBRIAN BORDER SAMPLE BY THIOUREA-TYPE CHELATE RESIN SEPARATION

Jin Li-Yun, Li Yun, Yang Ming Institute of Atomic Energy. P.O.Box 275(29), Bei jing,China

Abstract: The discovery of Ir anomalies in the Creta- Tertiary period sample indicated the significance in the re­ search of the earth evolution and disaster events. In the support of the method of RNAA-thiourea-type chelate resin separation developed by our laboratory, some Chinese geologists have also found significant Ir anomalies in precambrian-cambrian border sample recently. This new dis­ covery possesses important meaning in the research of precambrian-cambrian geological history. It is well known that to determine Ir in above geological- materials precisely is a very difficult task because of the complex matrix composition, low content of Ir(ppb-subppb level) as well as variable valence of trace Ir. To combine the high sensitivity of NAA with the excellent selectivity of thiourea-type chelate resin properly, a new method for determination of ultra-trace amounts of Ir in geological materials have been developed in our laboratory. Moreover, ultra-trace amounts of Ir in several sets of precambrian- cambrian border samples have been determined accurately, the significant Ir anomalies have been found positively. Weigh about 0,3g sample prepared by the Geological Reserach Institute in a aluminium tube.Irradiate sample along with pure Ir standard as well as NBS SRM(DTS-1, AG-Bohor-1) in 12MW HWRR with neutron flux of 4-7*1013n/cm2*sec for 30 hours. After cooling for one or more months, transfer ir­ radiated sample in a graphite crucible, add several micrograms of Ir carrier and mixed acid(HF-HCL-HN03) to ex­ pel the massive silicon on electric-plate. Then add 2,5-3,Og mixed fusion (Na202:NaOH) and fuse in a muffle furnace at 74 700 C for 15 minuties. After cooling, leach the fusion product with 5mL hot water. Acidify the solution with 8N HCL and transter to 50 mL beaker. Adjust the solution to pH 1,5- 2,0 with NH4OH. Pass the solution through a column filled with thiourea-type chelate resin((p4*10) at a flow-rate of 0,5mL/min. after washing the column with 20mL 0,5NHCL, remove the resin absorbed Ir to a plastic tube for measure­ ment. Produced Ir-192 activity was measured for 4000-10000 S by means of SCORPIO 3000 multi-channel computer-Ge(Li) detector system(CANBERRA). One sets of representative results were shown in Table 1. Table 1. Ir content in precambrian-cambrian border sample (ppb).

I- . of sample Ir content, | N. of sample Ir content 1 AG-403-la 0.33 j CG-3-11 0.78 AG-403-2a 0.16 j CG-4-2a 0.69 AG-403-5 0.42 | CG-6-2a 13.6 AG-403-6 0.086 | CG-10-3a 2.30 AG-403-8 0.39 | CG-672-e 0.19 AG-403-10a 0.69 j CG-672-f 0.17 AG-403-12 0.13 j AG-Bohor-1 0. 84/1.06* AG-403-14a 1.64 | DTS-1 0. 58/0.60* AG-403-15a 0.40 1 i •Reference values Following conclusions could be made from the data obtained: 1) The values obtained by this work for SRM (DTS-1,AG-Bohor- 1) are agree well with those reported in reference. Therefor the method developed in our laboratory is reliable. 2) The lower determination limit of the method is well satisfied with the need of sensitivity of Ir anomaly evalua­ tion. 3)Significant Ir anomalies in precambrian-cambrian border sample were observed in samples such as AG-403-14a, et al. 75 NUTRIENT AND OTHER TRACE ELEMENTS IN INSTANT SOUPS

George D. Kanias Radioanalytical Laboratory, National Research Center for Physical Sciences "Demokritos", Athens 153 10, Greece

The role of trace elements in the human life processes was recognized many years ago. Foodstuffs are the first and principal source of trace elements for the human body, therefore every information about the tra­ ce element content, its variation and the factors which affect it,are al­ ways opportune and important. Fresh and canned foods are intensively stu­ died for their nutritional trace element level and its variation after cooking, baking, frying, processing etc/1/. Dried foods are a new group of consumer products which has appeared the last twenty years. Their technology is developed continuously thus new products are presented frequently in the market. The first products were the infant foods. Ice cream, smashed potatoes, desserts, vegetables, sau­ ces and slow-preparing soups have followed the infant foods. The last two years also instant soups arrived in the Greek market. All these dried foods are characterized by their simplicity of preparing (sometimes mill: or water is enough), quickness (3-20 minutes of preparing) and the rela­ tive nutritional value due to their simultaneous containing of proteins, fats and carbohydrates. The principal content of all instant soups are : starch, fat,salt,spices, hydrolysed vegetable protein, monosodium glutamate and maltodextrose. Also different other products are added during the processing of a cer­ tain soup such as vegetables in vegetable soups, mushrooms in mushroom soups etc. According to the advantages mentioned above,it seems that instant soups will play an important role on the nutrition of people in the future,be­ cause the sociale requirements of present and future foods are : light foods, low calorie value, fast preparing etc. Thus a study on their nu­ tritional trace element content is needed. Also as far as we know, accor­ ding to the bibliographical data, information on the trace element con­ tent of instant soups is scarce. • Instrumental neutron activation analysis and gamma-ray spectroscopy have been applied in this work for the determination of nutritional trace ele­ ments such as cobalt, iron, manganese, selenium and zinc in all instant soups in the Greek market. Also some other trace elements such as cesium, scandium, silver, europium etc. have been detected by the same method in the same samples. The analysed instant soups were :tomato, mushroom,beef consome, pea with ham, vegetable, chicken, onion, St.Germain and vegeta­ ble with tomato. However in order to have a better evaluation on the tra­ ce element content in instant soups as well as to investigate if the ad­ vantage of fast preparing is accompagnied with an analogous nutritional trace element content, samples of slow-preparing soups from the Greek market were also analysed for the same trace element content.

76 The analysed slew-preparing soups are :Tamato, mushroom, chicken, chicken noodle, chicken egg-lemon, chicken rice, minestrone, egg macaroni, oxtail and asparagus. From the obtained results in instant soups, it was found that the highest value for iron (59 ppm) and zinc (19 ppm) is present in onion soup. To­ mato soups contain the highest concentration for rubidium (18 ppm), ce­ sium (0.059 ppm) and cobalt (0.49 ppm) while the highest values for sil­ ver (0.15 ppm), nickel (2.8 ppm) and scandium (0.0-21 ppm) are present in mushroom soups. After a comparison between the mean concentrations found in instant and slow-preparing soups, instant soups are obviously more rich in iron and cobalt than the slow-preparing ones. This is very"important for the human nutrition due to the known relation of iron to blood biogenesis as well as of cobalt to vitamin B12. Zinc content in both instant and slow-preparing soups is found to be at the same concentration level. How­ ever the mean concentration for zinc in instant soups is lower than in slow-preparing soups. Another very important evaluation of the nutritional trace element con­ tent in instant soups could be made after the comparison of the results found in this work with those existing in the literature for other very common foods such as rice, potatoes, avian muscle, porcine muscle etc. To the best of our knowledge only concentrations for iron and zinc exist in the relevant literature. Thus our comparison includes.only these two elements and it is reported in raw materials and not in cooked foods. Iron mean values in instant soups are found to be at the same concentra­ tion level with those reported for potatoes (pith), rice, avian muscle, bovine.muscle and porcine muscle /1-4/. For zinc the situation is dif­ ferent. The trace element content in a number of. individual results in instant soups is found at the same concentration level with the mean va­ lues reported for potatoes (pith), rice and pork. However, the zinc mean values in instant soups are about 8 times lower than the values reported for porcine, bovine muscle, beef and lamb, and 2 to 3 times lower than the values attributed to pork and avian muscle /1-4/. Xn conclusion we can say that dried foods and especially instant soups are a new potential consumer product due to their composition (mixture of vegetable and animal raw materials) and to their nutritional trace element content. Their iron content is higher than that in slow-prepa­ ring soups, while zinc content-is found at the same concentration level. In addition instant soups have the same iron nutritional value with rice, potatoes, (pith), bovine muscle, avian muscle porcine muscle while zinc nutritional value is lower than beef, lamb, bovine muscle and porcine muscle.

/1/ Mondy,N.I., Ponnampalam, R.,.J. Food Sci.,48 (1983) 1475-1478.r /2/ Tama, R.B., Tabekhia, M.M., Ibid 44(1979) 619-G21 /3/ Schricker, B.R., Miller;' D.D.> Stouffer, J.R., Ibid 47 (1382) 1020-1022. /4/ Zarkadas, C.G., Marshall,W.D., Khalili, A.D., Nguyen, Q..,Zarkadas G.C.,Karatzas,C.N.,Khanizadeh,S., Ibid 52 (1987) 520-524.

77 APPLICATION OF EXTRACTION CHROMATOGRAPHY IN NEUTRON- ACTIVATION ANALYSIS

V.K. Karandashev, S.S. G-razhulene Institute of Microelectronics Technology and High Purity- Materials, USSR Academy of Sciences, 142432 Chemogolovka, Moscow District, USSR

The radio-chemical separation methods are generally required for neutron-activation analysis (NAA) of various objects ( pure mate­ rials semiconductor compounds, rocks, soils, etc.) to achieve sufficiently low detection limits. To this end, extraction chroma­ tography is extensively used owing to its high separation efficien­ cy, selectivity and the possibility to render the separation proce­ dure automatic which is essential to analysis of high-activity ma­ terials.

We have developed a unified technique of NAA of 'semiconductor compounds Cd _Hg Te and Pb Sn ,Te and their starting components which illustrates the application of extraction chroma­ tography in analysis of pure materials. The technique is based on simultaneous sorption in the column of all the matrix elements in tine extraction-chromatographic system: carrier-PTPE; stationary phase- TBP+TOA; eluent- HCL solution.

The extraction-chromatographic behaviour of impurities has been studied upon their separation from the matrix elements. It is shown

thats as in the case ofextraction, the presence of the macrocom- ponent in the probe may change the distribution coefficients. As seen from Pig.l, the dynamical distribution coefficient may either decrease owing to extraction suppression (Ag) or increase owing to the coextraction effect (Sc).The eluate volume required for eluting the impurity element either decreases or increases accor­ dingly.

78 Fig.l. Curves of elu- tion of microamounts of Co (curve l), Sc (2) and Ag (3) with 5M HBr solution in the absence (A ) and presence (B) of 200nig of indium. The column is filled with 15g of PTPE with 5ml of 0.1 L TBP. H=15 cm; D = l.l cm; V =8 ml.

ml

The possible ways of the use of these effects for reducing the duration and number of the radio-chemical operations required for separation of impurities from simple and compound materials are discussed. The use of the effects of coextraction and extraction suppression in chromatographic columns with a macrocomponent - saturated organic phase is suggested to increase the selectivity of separation of microamounts of elements. The technique is illus­ trated by extraction - chromatographic separation of microamounts of scandium from a mixture of more than 30 elements in the system: carrier - PTPE; stationary phase -In- saturated TBP; eluent - 5M HBr solution.

79 'J-.0

Karpov, iu.A., Kudinov, B. 3. and Liurashov, h.V. otivco Institute Of liaro Kiet/'.ls, Wosoow, jjij^i

{Jas phase radiochemical, separation provides essential oelec- tivity and clearing both in neutron activation analysis and other methods using accelerators, i'hat separation can be fulfiled in limited time that la very important for short­ lived radionuclides. Induced activity measurements by Q -. counting in gas phase :na.lce it possible to detect also soft emitters, for instance -°3. A set for gas phase radiochemical separation has been built in our institute that allows inductive heating of samples up to 2000°C in vacuum or gas media. Extracted gas mixtures uro separated by fractional absorbtion or freezing. Induced activity measurements are performed "oy /3~counting in hollov/ olastic scintillator. Detector inner volume is 150 cm"', the wall thickness - 4 mm. Gas extraction method was used for sol­ ving the following pfoblems: l)i'Taorine determination in rare earth and refractory metals yj photon activation through tho ' ""i'^n}"'"'.? reaction. 'The Physical Problems Institute microtron of electron energy 23 KeV and average beam current 15 wA was used. Graphite cru - cible and. 5 g nickel bath were used in furnace. The bath contained .10% mass of silicon or boron depending on the ana­ lysed metal. The I g activated and etched sample was thrown down in the furnace with dehydrated La?~ as a carrier. The quantity of the latter was selected in such a way to provide 3.1?, or B?~ oressure over the melting-pot near 5 - 20.102 *a. Under such conditions the yield of fluorine in mens! one!

30 above gas compounds was about IOO#. Boron was used in analy­ sis of nigh melting-point metals. The extraction conditions were chosen by the thermodynamics computations [ij . The ext­ raction yield of some elements compounds interfering with fluorine in activity measurement was tested by radionuclide method ( P, Ge, As for instance ). The extraction time not exceed 10 min. Selected SiF, or BF, was frozen in liquid nit­ rogen trap and then directed in hollow 47T detector after sys­ tem pumping out. (Che limit of detection (L-jJ - 0.01 ppm. It is necessary to note the significant "memory" effect of scin­ tillator to BF,.

2) Carbon determination in silicon by mean$ of theI20(^,n)IIC reaction. The aluminium oxide crucible and oxygen saturated nickel bath were used. Carbon monoxide extracted at I700°C in vacuum was oxydated to COp by passing over CuO at 600°C, frozen in liquid nitrogen trap and then directed to detector. The method is applicable to carbon determination in some me-

tals. Freezing is necessary to eliminate ^K counting. LD for I g sample - 0.02 ppm.

3) Silicon determination in Mb by pile neutron sctivation analysis. The method of separation was similar to that desc­ ribed in point I). AlpO, crucible was used. F was brought in

nickel bath as CuF9 or laF, up to concentration 0.5/6. Sili- con with radionuclide J Si was extracted in gas phase as SiF, The extraction temperature was ~I900°C. L^ for neutron flux 101 ^4 n/cm2 .s was about 0.1 ppm.

4) B, 0 and Si trace determination in nonactivated samples.

These impurities were extracted as COp, BF, and SiFA com- II 18 pounds marked by C and F radionuclides. [ij CnHHpeB T.B. is. j]p. npiwieHeHHe 3BM JULK TepMOOTawiiraecKHX pac^eTOB MeTajmypriraecKHX npoueccoB, M. ,HayKa, 1982

81 Pseudocyclic Activation of Geological Material

G. Kennedy and S. Hobeika Ecole Polytechnique, P.O. Box 6079 Station A Montreal, H3C 3A7, Canada

Neutron activation analysis of geological material using short-lived isotopes is hampered by the intense 28A1 activity. Also, the statistical precision is limited by the short counting time available. This can be improved only slightly with cyclic activation since the 28A1 activity builds up with each cycle. In this work the possibilities of pseudocyclic activation, where the interfering activity is allowed to decay almost completely before the sample is sent back to the reactor, are investigated. A reliable system was constructed to exploit this technique, and results are presented for the pseudocyclic activation analysis of nine well known standard rocks.

Pseudocyclic activation is applicable when a number of similar samples are to be analysed. After the first cycle of the first sample, the remaining ones are activated and counted while waiting for the activity of the first one to decay. The procedure is repeated for several cycles to improve the counting statistics. We show that the results are superior to regular cyclic activation. A system was constructed to carry' out automated pseudocyclic activation. The pneumatic system includes two divertors, and samples are transported in a triangular fashion from front of sample stack to reactor, from reactor to detector, and then from detector to back of sample stack. Four timers control irradiation, decay, counting, and cycle times and the end of each operation triggers the next. After a number of adjustments to eliminate electrical transients from solenoid valves, the required reliability of a thousand consecutive irradiations was achieved. Nine standard rocks were analysed to test the system and to compare pseudocyclic activation with one-shot and regular cyclic activation. The nine samples, of approximate mass one gram, were irradiated for 2 seconds in the SLOWPOKE reactor with a thermal neutron flux of 1011 cm"2 s"1. After a decay time of 1.5 seconds they were counted for 10 seconds with a 13% germanium detector and all spectra were stored on disk. The procedure was repeated for 25 cycles. The time between consecutive irradiations of the same sample was 6 minutes, which allowed the 28A1 activity to decrease substantially. At the end of the run the appropriate spectra were added together to produce 9 summed spectra. Dead-time

82 losses were measured by the pulser method and they were found to be 13%, on average, for the first cycle and 17% for the 25th cycle. The spectra were processed for 19 elements with half- lives between 2 seconds and 2 minutes, and the results are shown in the tabel below. In many cases the element was not detected due to low sensitivity and high Compton background; the number of cases in which the element was detected is indicated in the last column. The detection limits, calculated from the. statistical fluctuations. in the background counts, are also shown. Table 1: Detection limits in rocks with pseudocyclic activation, 25 cycles.

Isotope Half-life Energy Det.Lim. 3?imes (s) (keV) (Mg/g) Detected

F20 11.0 1633 160. 6 Sc4 6 18.7 143 0.3 8 Ge75 47.7 140 160. 0 Se77 17.4 162 1.6 0 Br 7 9 4.9 207 41. 0 Rb86 61.2 556 115. 2 Y89 16.1 909 98. 0. Rhl04 42.0 556 1.8 0 AgllO 24.4 658 1.5 0 Inll6 2.2 162 0.05 2 Dyl65 75.4 108 1.1 7 Erl67 2.3 208 1.3 2 Ybl77 6.4 104 12. 0 Hfl79 18.7 214 0.2 8 W183 5.4 108 80. 0 Irl91 4.9 129 150. 0 Irl92 87.0 58 7. 0 Ptl99 14.1 392 1600. 0 AU197 7.8 279 33. 0

The statistical precision of the pseudocyclic measurements was found to be a factor of 4.7 better than one irradiation, which is close to the theoretical limit of 5 for 25 cycles. Regular cyclic activation with a cycle time of 2 0 seconds was also attempted but only the first 4 cycles were usable, the dead-time having exceeded 40%; an improvement in precision of a factor of 1.6 was obtained compared to one irradiation. Results will also be presented for pseudocyclic irradiations with epithermal neutrons using boron filters.

83 TREE RINGS AS MONITORS OP HEAVY METAL AIR POLLUTION HISTORIES

G. Kennedy and S. Bergeron Ecole Polytechnique, P.O. Box 6079, Station A Montreal, H3C 3A7, Canada

The knowledge of heavy metal air pollution histories is of considerable importance since the health of human populations may be seriously affected by long-term exposure to low levels of toxic metals [1]. A number of previous studies have reported that tree rings may be useful as monitors of heavy metal pollution histories. The majority, however, were carried out near roads and dealt with lead deposition from automobile exhausts and we know of no detailed study directly comparing conifers with deciduous trees. The work of Baes and McLaughlin [2] suggests that conifers are better monitors while Lepp [3] states that ring- porous deciduous species should be superior. The present study compares two coniferous species with three deciduous species and we report the first numerical values expressing the ratio of the concentration of the metal in the wood to the amount deposited per square meter of ground. Our study was carried out at a wooded area one kilometer from a refinery producing manganese. The aim was to compare the concentrations of heavy metals in the annual growth rings with the estimated annual amount of deposition from the atmosphere since the startup of the refinery. At the polluted site, xylem samples were taken from ten trees of each of the following species: hemlock (tsuga canadensis), cedar (thuja occidentalis), maple (acer saccharum), poplar (populus deltoides), and ash (fraxinus pennsylvanica). Bark samples were also taken for analysis. The xylem samples were taken with an incremental corer which was inserted into the tree only after a small area of bark had been removed, to avoid contamination by metal deposited on the surface of the bark. The core samples, which usually covered 50 years' growth, were sliced into two year sections and these were analysed for heavy metals using neutron activation. They were irradiated in the lO^cm^s"1 neutron flux of the Ecole Polytechnique SLOWPOKE reactor and counted with germanium detectors in order to determine as many elements as possible. Concentrations were calculated as a function of dry weight. The amount of contamination from the metallic instruments used was measured by activating them in the reactor and was found to be negligible.

84 Samples were also analysed from control trees growing 3 0km from the refinery. Increased amounts of Al, Cr, Mn, Fe, Cu, Zn, and As were found in the trees from the polluted site, both in the xylem and in the bark, although for most elements the increases in concentrations in the xylem were barely significant. Mn was by far the most abundant metal at the polluted site; as much as 3 0000 /jg/g was found in the first millimeter of bark. Mn was therefore chosen for the comparative study. Higher Mn concentrations were found in the xylem of the two coniferous species, hemlock and cedar, than in the three deciduous species. Large variations were found among the ten individuals of any one species, which implies that one tree is not a reliable quantatative indicator of metal deposition. The 50 year Mn profiles for the five species were compared with the relative emission rates from the refinery estimated from the startup date, production rates, and the installation of anti-pollution equipment. The advantages of expressing the data in /xg/year rather than fig/q ware considered. The usefulness of these temporal data will be presented considering the effects of increasing Mn concentrations in the soil, changes in availability due to acid rain, and possible lateral translocation in the xylem. Soil samples were also analysed to estimate the total amount of Mn deposited on the ground since the beginning of operation of the refinery. These data, when compared to the integrals of the profiles obtained from the rings, give the collection efficiencies of the five species, i.e. the concentration in the xylem as a function of the amount deposited per m2 of ground. [1] Nriagu, J.O., Environmental Pollution 50 (1988) 139-161. [2] Baes, C.F. and McLaughlin, S.B., Science 224 (1984) 494- 497. [3] Lepp, N.W., Environmental Pollution 9 (1975) 49-61.

85 PROMPT GA?I?1A-RAY NEUTRON ACTIVATION ANALYSIS BY niu ABSOLUTE METHOD

Y.-5. Khrbish* and N-.N. Spyrou** * Tajoura-Nuclear Research Center, P.O. Box 30878 Tripoli-.Libya. ** Phv-sics Department, University of Surrey, Guilford. Surrey. GU2 5XH (U.K.)

Prompt Gamma-ray Neutron Activation Analysis (PGNAA) is routinely used as a complementary technique to the conventional noutron activation analysis for the elenental analysis of B. Cd and some rare earth elements at trace levels as well as for H. CI, S etc. at percent levels. PGNAA often requires long irradiations and to handle so many standards as the case is in the comparator method is not only cumbersome and time consuming, but is a source of additional errors during preparation, mixing, dilution and counting of the standards. The usual practice is to use standard reference materials (SRM) or certified reference materials (CR?1) as multi-elemental standards. These reference materials az*e not always available and difficulties may arise when one is to analyse a new type of material which has a different elemental composition from the reference' materials available or where the element sought has no certified value. An inherent source of error is the possible change of certified concentration data with time as more data are accumulated. An investigation into the possible applicability of the absolute method in PGNAA was undertaken. In order to establish the absolute or rather the non-comparator method good and accurate knowledge of all the nuclear and system parameters involved and reliable and reproducible experimental conditions are needed. In practice this means evaluation of all the parameters in the so-called activation equation with good accuracy and precision. To realise this the task was divided into two parts; system characterisation and nuclear data evaluation. A thorough study was carried out for the former [1,2]. In that study the effect of the geometric solid angle as well as the orientation and displacement of the target (cylindrical/disc) on the reproducibility of the experimental set up were reported and a measure of tolerance on reproducibility in activity quantification was discussed. The non-uniformity of the induced activity and its effect on the geometrical factor and the variation of this factor with position of the target were also reputed. A major portion of the change in the detector

86 efficiency with target diameter is a geometric change, but the dependance of the detector efficiency on gamma ray energy compels the determination of other factors in addition to the geometric solid angle. All these factors combined result in the effective solid angle [3]. The necessary link between the experimentally determined efficiency using calibrated point sources and the needed efficiency of volumetric sources was provided by applying the respective effective solid angles calculated [4].

The usefulness of the activation equation is still limited by the unreliability of . our knowledge of nuclear data. Although the system parameters are adequately characterised, the scatter in nuclear data for a number of elements is significant. For our particular experimental set up the K-factors [4] were calculated for a number of elements using both Au and Fe as mono-standards. A comparison was made between the calculated and experimentally determined K-factors and from this comparison the feasibility of using the absolute method in neutron induced prompt gamma rays can be realised for a number of element. [1] Nicolou, G.E., Khrbish, Y.S. and Spyrou, N.M., Int. J. Appl. Radiation Isotopes, 37 (1986) 1219-1224. [2] Nicolou, G.E., Spyrou, N.M. and Khrbish. Y.S., J. Radioanal. Nucl. Chem.. 114 (1987) 195-202. [3] Moens, L. et al., Nucl. Instr. and Methods, 187 (1981) 451. [4] Khrbish. Y.S. Ph. D Thesis (Physics), University of Surrey (1987)pp. 81-85.

87. INSTRUMENTAL NEUTRON ACTIVATION METHODS TO MEASURE SHORT-TERM ACCRETION AND EROSION IN WETLANDS WITH RARE EARTH SOIL HORIZON MARKERS

Ronald M. Knaus Nuclear Science Center Louisiana State University Baton Rouge, LA 70803-5820

Quantitative information on short-term (<. one year) sedimentation and erosion rates of fine particulate matter in endangered freshi brackish, and saltwater wetlands is essential for effective management of these habitats. The rapidity of man's current impact on marshlands worldwide makes estimates of past sedimentation and erosion rates obsolete. Traditional estimates of annual shifts of sediment are often deduced from deep cores, the data from which are averaged over several years and extrapolated into present time. Estimates also are made by measuring displacements or additions of sediment next to calibrated pins placed in the marsh. Another methodology measures accumulations of sediment above one-cm thick visual markers previously placed in the marsh; both" of these methods may significantly interfere with the sediment transfer processes which are under study.

The use of rare earth soil horizon markers, samarium (Sm) and dysprosium (Dy), overcomes problems of interferences in natural sediment transport processes because the stable tracer, intimately mixed with newly worked sediment, is used either in tracer quantities (<100 ppm) for accretion studies or is at maximum levels of < 50,000 ppm for erosional studies. In erosional studies the subsequent tracer concentrations away from the loci of erosion, where the higher concentrations of the rare earth tracer were placed, rarely exceed 25 ppm. Two rare earths were used together to serve as an internal-check on the method and to overcome possible interferences of other induced radionuclides in the samples. Dy concentration in samples is determined from the 0.094 MeV decay gamma ray from 2.35-h 165Dy,

88 produced from the Dy(n,-v) Dy reaction, and is counted 2- to 5-h post neutron irradiation. Sm concentration is determined from the 0.103 MeV gamma from 46.5-h 153Sm, produced from the 152Sm(n,7)153Sm reaction, and is counted 48- to 72-h post neutron bombardment.

After stable tracer application in the field and after an appropriate time interval to allow for sedimentation or erosion to occur, samples of marsh sediment are processed for instrumental neutron activation analysis. Approximately 70 mg of the dry sample is placed in a clean 2/27-dram (0.2 mL) polyethylene activation vial. This vial is heat sealed and placed within a 2/5-dram (1.5 mL) vial which also is heut sealed. To conserve time and costs, two of the 2/5-dram vials are placed in a single 2-dram (7 mL) vial for irradiation via a pneumatically driven system of a research nuclear reactor. Samples are neutron (thermal) irradiated with 1013 n-cm^sec'1 for limes varying from 2 to 4 min, depending on sodium content. After irradiation, the samples are stored for approximately 2 h to allow much of the short­ lived activity to decay prior to the first gamma ray assay (count) for Dy determination. The activation products from chlorine, sodium, and other elements in the sample decrease in 2-3 days when the sample again is counted for its Sm content.

Because of a familiarity with marsh samples gained over years of research, a high degree of accuracy is not necessary in assessing the concentration of the rare earth tracers in core sections. Therefore, an absolute standard method, obviating the. time and expense of handling standards, has been adopted using the software available from EG&G, Ortec, in Oak Ridge, TN (Model A30-BI, Germanium analysis software). This program has a calibration routine (SRM 4275-B-53) using an NBS mixed radioisotope standard of !23Sb, 15,1Eu, and I35Eu.

By carefully recording the varying concentrations of the rare earth tracer with depth in the sediment, it is hypothesized that various marsh types under specified stresses can be characterized so practical remediation procedures can be prescribed.

39 Protein Determination in Single Grains by Instrumental Neutron Activation Analysis

J. Knorr+, M. Schiskai+,, W. Franks"*", F> Focke* Technical University of Dresden, Mommsenstr. 13, Dresden, DDR-3027 Institute far" Plant Growing, Bernburg-riadmersieben, SDR

D^tsrir-inatiorc of pr otsin content in food materials is usually done analysing the nitrogen a.ir.cu.nt hy wat chemical KJ^ldjf'il—mafchadr An unproved :nL There is a keen interest, however, to determine protein concentration of single grains to shorten the tine for growing new 'species. In thi:: C&Z-G it will ba possible to select those corns with wanted properties using them for racing the ne.vfc generation of plants.

Analysis have been made using 14 MeV neutrons from a cont­ inuously pumped nsatron generator determining content of N ••3.:"td P in single wheat corns. Activation creates the nuclides y\' and \ '~F using ;'n,2n)-reaction

1 1 ^N(n,2n) ^>4, T1/? = 7.76 min

31 30 15P(n,2n)15P, T1/2 = 2,5 min.

Irradiation parameters have been investigated and optimiz­ ed to prevent seriously radiation damage in the corns. Resulting from this investigations irradiation time had been chosen 30 min, followed by 3 min cooling time. Both

90 final nuclides dee:

About 200 single corns have besn investigated with total net weights from 30 to 70 mg. The tested arrangement allows determination of nitrogen amount in a single corn down to 0.3 mg with an a.c.c\±ra.z.y of 47.. Mean nitrogen concentrations in the range of 9 to 197. per corn have been obtained. These results show, that all requirements of laboratory single grain protein analysis will be satisfied by this method.

91. NEUi'EON ACTIVATION ANALYSIS IN SOLVING UNIQUE GEOCHEMIOAL AND COSMOCHEMICAL PROBLEMS G.M.Kolesov V.I.Vernadsky Institute of Geochemistry and Analytical Chemistry, U3SS Academy of Sciences, Kosygin street 19, II7975, Moscow V-334-, USSR. Distribution and composition data of Lithophilic, Sydro- phiiic and Ghalcophilic elements show evidence in favour of genesis and changes following it in terrestrial and extraterrestrial master. Many of these elements, for example REE,Hf ,i!a,Ih,U, platinum metals and As,Sb are relatively simple and are determinable with low detection limit by neucon activation analysis. Experiences in analysis accumulated from our laboratory were used for investigating unique processes, the forma­ tion of solar system objects and their evolution. Among them are the following: - Formation of chondrites, genesis of ultra-refractory inclusions in carboneceous chondrites, formation of meta­ llic and silicate phases of iron and stone meteorites and formation of different chemical group iron meteorites. - Change in composition of regolite and lunar rocks, differentiation of upper mentle matter. - Identification of terrestrial meteorite craters and introduction of extraterrestrial (meteorites) materials onto the Earth, investigation of unique events type Tunguska of year 1908. - Study of the ore formation processes, geochemical barrier processes like river-sea and ocean-atmosphere and etc. These investigations are based on the trace element content data which are obtained with the help of instrumental and radiochemical methods of neuton activation analysis. Analysed samples were irradiated with thermal and epi- thermal neutrons. In every case the optimal irradiation and cooling conditions were facilitated. Gama spectra of radionuclides and calculations of elemental concentrations were done using computer. Such approaches allowed to determine about 50 elements in I-100 mg samples. The detection limit varies from I0"1 to 10-^0% with relative standard deviation 3-30%.

92 iiiQaj.1 sizf?s and low aassea of sanies and ineir unusual composition is one oi tne specific lecture in analy^in^; natural objects, j-'ua to their uniqueness the analysis is oarrieu. oat; without destruction oi samples. i*e termi­ nation oi' cnemical composition or suen sanies by neutron activation, analysis is wiaeiy applied. i'o.r iursher modification of Uietnoa following; su&ges-sio-us &re outlined: i. Increasing the efficiency of analysis (, iihe development; of simple sober e for decomposition ox samples ana elemental cr»ncer oration ana usin;1; computer for treatment of r»sult3 of une analysis) 2. acauoing one defection limit \. carrying OIK effective mstnods xor treatment of 3j,e- cjwi'ii, aaiiigj with fjigii resolution semiso.'idu-t u- c'e«eoWX' equipped with uu-tichannel analyser, yrocesser or opii"iiti3;:ts.Oa< an-i co-iem ^adio-hei-ic:;! ..^ tirade / 3. iiiiresi.siiife accuracy aad reproducibility of results •^ choosing optimal regime for analysis and samples witr. hign quality ana different composition,, numerous .--eal examples for i: .""'os^i;,&tia-3 tna above •aen- tionea problems •'"-re coinmunica&ea.

93 NEUTRON ACTIVATION DETERMINATION OF IRIDIUM AND SOME NOBLE METALS IN ROCKS,IMPACTITES AND OTHER GEOCHEIHCAL SAMPLES G.M.Kolesov, L.D.Barsukova, A.Z.Miklishansky, M.A.Nazarov and D.Yu. Sapozhnikov V.I.Vernadsky Institute of Geochemistry & Analytical Chemistry, USSR Academy of Sciences, Kosygin street 19, 117 975, Moscow V-334, USSR. In view of especially lov; contents of platinum metals in terrestrial matter (unlike, for example in meteorites), these elements particularly Ir and Os are used as indi­ cators in introducing the extraterrestrial materials into the Earth (or the Moon) to know the geological history. In particular, these elements were found very useful in knowing old meteoritic craters, in revealing the events occuring in main stratographical boundaries. In order to enhance reliability and universality of ana­ lysis, such samples were analysed by three different methods of sample decomposition. In the first method, the irradiated samples were decomposed with the mixtures of acids (MC1+HN0-+HP). In second variety method, irradi­ ated samples were^melted with sodium peroxide and decom­ posed with hydrochloric acid. Adsorption of platinoids in both cases from 1-3 M hydrochloric acid takes place on chelating sorbents (tertiary amine or polyvinylbenzyl- methylpurazole). In third method, samples were alloyed with the mixture of potassium tetraborate, sodium carbo­ nate, silicon dioxide, sulphur and nickel for the concen­ tration of platinoids, silver and gold in sulphide nickel bead. Semiconductor detector and multichannel analyser were used for the activity measurements of Ir,0s,Pt,Ru,Pd,Ag, Au radionuclides. Samples weighing 0.5-1.0 g are irradiated for 20-100 hours under a neutron flux of 1,2.10-13 neutrons cm~2. S-A Measurements were made for a time period of 1000-5000 sec. Detection limit of Ir and Au was 5.10-10/"J and for 0s,Pt, Ru,Pd,Ag was found to be n.10~8 % with error being 10-40%. In quantitative microassy concentration method, if the contents of platinoids is :> n.10"? % preliminary platinum metals enrichment is made or if contents is -s n.10~' % enrichment is made after irradiation.

94 During the analysis, these methods were tested with respect to standard samples of rocks, meteorites and copper nickel ores. For platinoids distribution studies (especially iridium) the success depends upon specific composition of samples. Using these methods iridium was measured in sedimentary rocks of the following geological boundaries; Bocene/Oligocene (Crimea), Cretaceous Ter­ tiary (10 localities), Callovian/Oxfordian (Spain and Poland), Triassic/Jurassic (Austria), Permian-Triassic (Armenia and Italy) and Precambrian/Cambrian (Siberia). In addition to this iridium and some noble metals were also determined in the sedimentary rocks of the Russian platform, Archaean rocks, impactites of USSR impact craters (Kara,Popigai,Boltysh et. al.) and also in the peats from the region of the Tunguska catastrophe. • Based on these studies an average abundance of Ir in the crystal rocks was found to be 20 pp . The Cretaceous/ Tertiary boundary sediments are very high content of Ir (up to 67 ppb in Sumbar section) that shows a gigantic impact event at the boundary. A small Ir anomaly was also established at the Callovian/Oxfordian boundary. Impac­ tites of some craters as well as the Tunguska peats formed in 1908 show a distinct Ir enhancement to that of back­ ground level. Other studied boundarysediments and impactites do not contain any firm iridium evidence for accretion of extraterrestrial material.

95. SPECIAL FEATURES OF COMPOSITION OF LUNAR BASALTIC ROCKS BY NEUTRON ACTIVATION ANALYSIS

G.M.Kolesov, A.F.Kudryashova, A.Mashtalka , L.S8Tarasov, Ya.Frana , N.A.Shubina. V.I.Vernadsky Institute of Geochemistry & Analytical Chemistry, USSR Academy of Sciences, Kosygin Street 191 117975. Moscow V-334, USSR; ^Institute of Nuclear Physics, Czech. Acad, of Sci., 25068, fiez near Prague, CSSR. Instrumental Neutron Activation Analysis has been under­ taken for the detailed studies of the chemical composition of lunar basalts. The samples supplied from automatic space station "Luna-16" and "luna-24"are characterised with high (8% Ti02) and low (0.8% TiOp) contents of tita­ nium and high consent of aluminium (15% AlpO,). For the purpose of reliable data on the biggest element number the analysis of the samples have been made by two stages - by short-lived radionuclides using pneumatic system and by long-lived radionuclides with integral neu­ tron flux of 2.2-10 p n- cm" and 8.6'10 ''n*cm" , respec­ tively. The samples weighed 0.5-10 mg.Activity measurements were carried out with gamma-ray spectrometer with Ge(Li) semiconductor detector of high resolution and with 4096-, 8192-channel analyser. Spectrometries data were processed using computer. Results of Al, Ca,Mg,Na,Ti,Dy,V,Mn,Eu elements were obtained at the first stage and results of Fe,Cr,Co,Sc,Zr,Hf,Ta.Rb,Cs,REE and other elements obtained in the second stage (on the whole 40 elements with 5-15% error were determined). Graphical correlations of geoche- mically identical rock samples were made using computer. Correlation depending on comparison for pair of elements of "Luna-16" and "Luna-24" rocks points out the'differen­ ces of two series to the distribution of REE,Ba,Zr,V and other elements and two stage (phase)' formation of magma from Mare of Fertility. Basalts of "Luna-24" are charac­ terised with lower contents of incompatible elements in comparison with the other lunar basalt samples collected from different regions of moon including Mare of Fertility. Low level contents of trace and rare earth elements ob­ served in the rocks of "Luna-24" suggests the weak Geoche-i mical variations of magma in Mare of Crisium. Similar types of investigations were also made with the sampes which are supplied from spaceship "Appolo".

96 ASPRO I A SOFTWARE PACKAGE FOR AUTOMATIC PROCESSING OF GAMMA-RAY SPECTRA

V.P.KOLOTOV , V.V.ATRASHKEVICH, I.VAVIDA,P,NAGY, F.BRECH, A,KADAR,F.VASARHELY INSTITUTE OF GEOCHEMISTRY AND ANALYTICAL CHEMISTRY,USSR ACADEMY OF SCIENCES,Moscow,USSR ELECTRONIQUE MEASUREMENT GEAR(EMG),BUDAPEST,HUNGARY.

A SOFTWARE PACKAGE FOR FAST, EFFECTIVE AND COMPREHENSIVE PROCESSING OF GAMMA-RAY SPECTRA HAS BEEN DEVELOPED, THE PROGRAMS RUN IN THE COMPUTER-BASED ANALYZERS SUCH AS LP-4900 B ( NOKIA / AFORA , FINLAND ), NUC-8000 (EMG, .HUN­ GARY) AND ARE ADOPTED ALSO FOR ANALYSER BASED ON IBM PC AT/XT. THE ARCHITECTURE OF THE ASPRO PACKAGE ENSURES THE FULLY AUTOMATIC ANALYSIS OF SPECTRA FROM FOUR INDEPENDENT LINES OF ACQUISITION AS WELL AS FROM SPECTRA STORED ON DISK, IT MEANS THAT DATA IDENTIFICATION, ACCESS TO REQUIRED DATA (CALIBRATIONS, CONDITIONS OF ACQUISITION, CONTROL PARAME­ TERS), DISK OPERATIONS, PROTOCOLS DUMP, ETC, NEED MINIMUM ATTENTION OF USER, THE PRINCIPAL FLOWCHART OF THE SOFTWARE ASPRO is PRESEN­ TED ON FIGURE 1. As IT FOLLOWS FROM THE FLOWCHART THE PAC­ KAGE CONSISTS OF A NUMBER OF PROGRAMS EXCHANGING INFORMA­ TION WITH EACH OTHER THROUGH EXTERNAL MEMORY ON DISK.. THE PROGRAM DIALOG IS INTENDED FOR LOOKING THROUGH OR PROVIDING MODIFICATION TO THE PARAMETERS CONTROLING THE SPECTRUM PRO­ CESSING, ALL PARAMETERS ARE PRESET FOR THE MOST ""TYPICAL'7 CASE OF PROCESSING (DEFAULT PROCESSING), THE DIALOG SUGGESTS USER A "MENU" OF TASKS AND PROVIDES A DETAILED INFORMATION CONCERNING THE FUNCTIONS OF ANY PARAMETER NEEDING MODIFICA­ TION, THE PROGRAMS CALEN, PSCAL AND CALEF MAKE.ENERGY, PEAK SHAPE AND EFFICIENCY CALIBRATIONS, RESPECTIVELY. THE. CALIB­ RATION PROGRAMS FUNCTION AS IN THE CASE OF INTERACTIVE MODE OR FULLY AUTOMATICALLY. ASPRO IS A CENTRAL PROGRAM OF THE PACKAGE. IT INCLUDES THE NEXT FUNCTIONS! PEAK .DETECTION, SEARCHING PEAKS' BOUNDA­ RIES, BASE-LINE CREATION, DECON.VOLUTION OF THE OVERLAPPING PEAKS BY MEANS OF METHOD OF MOMENTS (USING THE EXPEREMENTAL PEAK SHAPE AND REGULAR IZATION ALGORITHM TO INCREASE THE STABILITY OF MULTIPLES' DECONVOLUTION), CALCULATION OF PEAK AREA, FWHM AND SOME OTHER DATA, DUE TO APPLICATION OF ORIGINAL ALGORITHM ASPRO DEMONSTRATES EXTRAORDINARY^PROCES-' SING SPEED. THE QUALITY OF DIFFERENT PARTS OF THE ^PROGRAM HAS BEEN CHECKED BY MEANS OF IAEA TEST SPECTRA. IT HAS BEEN FOUND THAT ASPRO PROVIDES EXCELENT RESULTS.

97 ASPRO CAN BE CALLED AS A MAIN PROGRAM AND AS A SUBROU­ TINE OF THE PROGRAMS IDENT AND ANAL WHICH USE THE RESULTS OF ASPRO AS START DATA FOR FURTHER PROCESSING, TO INCREASE RELIABILITY AND SPEED OF THE ISOTOPE IDENTI­ FICATION PROGRAM (IDENT) THE VAST NUCLEAR DATA BANK (CAPA­ CITY OF ABOUT QJ MBYTES, CONTAINING INFORMATION ON ACTIVA­ TION AND DECAY OF MORE THAN 400 ISOTOPES. INCLUDING MORE THAN 7200 GAMMA-RAY TRANSMISSIONS AND DATA OF INTERFERING REACTIONS WITH FAST NEUTRONS) SHOULD BE REDUCED TO THE SIZE OF ACTUAL FILE. THE REDUCTION IS CARRIED OUT BY PROGRAM ISOTA TAKING INTO ACCOUNT DATA OF THE CONDITIONS OF ANALY­ SIS ( NEUTRON FLUX,. DURATION OF IRRADIATION AND COOLING ) AND AVAILABLE A PRIORI INFORMATION ON THE SAMPLE COMPOSI­ TION, FOR QUANTITATIVE NAA TWO PROGRAMS HAVE BEEN DEVELOPED I ANAL AND QUANTA. PROGRAM ANAL IS INTENDED FOR ROUTINE NAA BASED ON RELATIVE STANDARDIZATION BY MEANS OF COMPARISION OF SEPARATE GAMMA-LINES FREE NUCLEAR INTERFERENCES IN THE ANALYSED AND REFERENCE SAMPLES. THE CHOICE OF THESE LINES IS MADE BY THE USER FROM HIS OWN EXPERIENCE OR WITH THE HELP OF PROGRAM IDENT, THE PROGRAM ANAL WORKS FULLY AUTOMATICALLY INTRODUCING ALL NECESSARY CORRECTIONS. THE PROGRAM QUANTA REPRESENTS THE MOST GENERAL WAY OF QUANTITATIVE NAA I - TAKING THE RESULTS OF ISOTOPE IDENTIFICATION, NUCLEAR DATA BANK, CONDITIONS OF THE ANALYSIS, FROM AVAILABLE IN­ FORMATION ON THE SAMPLE COMPOSITION THE PROGRAM ESTIMATES POSSIBLE WAYS OF ORIGIN OF EACH IDENTIFIED RADIONUCLIDE CONSIDERING THERMAL AND EPITHERMAL NEUTRON ACTIVATION,BUR­ NING UP EFFECTS, THRESHOLD REACTIONS WITH FAST NEUTRONS, FISSION OF U AND TH - FROM INFORMATION ON ORIGIN OF EACH RADIONUCLIDE THE PRO­ GRAM COMPUTES THE CONCENTRATION OF DETERMINED ELEMENTS BY MEANS OF COMPARATOR METHOD, . IN ADDITION TO THE ABOVE MENTIONED PROGRAMS THE PACKAGE INCLUDES ALSO A LOT OF AUXILIARY PROGRAMS ( MONITORING OF NEUTRON FLUX, COMPUTING CORRECTION FOR GEOMETRY DIFFERENCES OF THE SAMPLE AND STANDARD, ETS),

98 SIMPLE RADIOCHEMICAL PROCEDURE FOR DETERMINATION OF SOME ESSENTIAL AND TOXIC ELEMENTS IN BIOLOGICAL SAMPLES BY NAA

V..P.KOLOTOV, LE TAT MUA, N.N.NEKRASOVA

Institute of Geochemistry and Analytical Chemistry USSR Academy of Sciences, Moscow, USSR

A SIMPLE METHOD BASED ON CHROMATOGRAPHIC TECHNIQUE HAS BEEN DEVELOPED FOR FAST DETERMINATE OF AS,SE,MO,CU,CD, ZN,HG IN BIOLOGICAL MATERIALS SUCH AS IN POWDWRED MILK AND WHEY, PLANTS, SOME KINDS OF FOOD ETC. THREE COLUMNS WITH THE FOLLOWING CHARACTERISTICS ARE USED; GEOMETRY- H= 5CM, D=0.6 CM, CARRIER- HYDROPHOBIZED SILICAGEL,CHROMATON N-AW-DMCS, 0,16- 0,20 MM, FIXED PHASE - 20% OF CARRIER WEIGHT, 1-ST COLUMN WITH DODAT (DIOCTYLDIACETATOTIN WITH 10% OF OCTANOL), 2 2-ND AND 3-RD COLUMNS WITH ZN(DDC)2 DO" M SOLUTION IN CHLOROFORM, DDC= DIETHYLDITHIOCARBAMATE). THE IRRADIATED SAMPLE WITH THE CARRIER IS DECOMPOSED IN TEFLON BOMB WITH THE MIXTURE OF HNO3 (10. ML) AND HCLO^ (0.5 ML) AT THE TEMPERATURE OF 150°C FOR 2 HOURS, THE OBTAINED SOLUTION IS EVAPORATED TILL APPEARENCE OF PERCHLORIC ACID FUMES. THE SAMPLE IS DILUTED WITH WATER AND NEUTRALISED WITH NH3UQ) TO PH 3-5. THE FURTHER STEPS OF ANALYTICAL PROCEDURE ARE SHOWN ON THE FIGURE 1. SOME COMMENTS CONCERNING THE RADIOCHEMICAL SCHEME ARE PRO­ VIDED BELOW. AFTER THE ELUTION OF THE SOURCE SOLUTION THE COLUMN IS. WASHED WITH 20 ML OF 0,1 M SOLUTION KBR* NAQSO,, AS A BACK CARRIER FOR RADIONUCLIDES ^4NA, BR. THE SECOND STAGE IS INTENDED FOR ADDITIONAL PURIFICATION

99 OF SE AND MO PREVENTING INTERFERENCE OF 32P, THE MEASUREMENT OF ISOLATED FRACTIONS (THE ORGANIC PHASES OF THE COLUMNS 1 AND 3 ARE WASHED OUT WITH ACETONE) IS CARRIED OUT BY MEANS OF GE(LL) DETECTOR COUPLED WITH COMPUTER-BASED MULTICHANNEL ANALYSER FOR SPECTRUM EVALU­ ATION AND CALCULATION OF THE ELEMENTS CONCENTRATIONS, THE DEVELOPED PROCEDURE *HAS BEEN TESTED BY MEANS OF ANALYSIS OF SOME REFERENCE MATERIALS OF IAEA,

FIG.1. RADIOCHEMICAL SEPARATION SCHEME

STAGE 1 STAGE 2

SOURCE —*\X) 3M HCL SOLUTION I

AS(V), SE(IV) MO(VI), P(V)

HG, CU, CD,ZN SE(IV),f10(VI)

PERISTALTIC PUMP

100 STUDY OF CHEMICAL SPECIES OF ANOMALOUS IRIDIUM IN CRETACEOUS/TERTIARY (K-T) BOUNDARY CLAY WITH RADIO­ CHEMICAL NEUTRON ACTIVATION ANALYSIS AND CHEMI­ CAL STEPWISE DISSOLUTION PROCEDURE

Kong Ping, Chai Chifang, Mao Xueying, Ma Jianguo and Ma Simian • Institute of High Energy Physics, Acadeinia Sinica P.O.Box 2732, Beijing, China

The study of Cretaceous-Tertiary (K-T) boundary event is now focused on its for­ mation mechanism: extraterrestrial, volcanogenic, biogenic or geochemical. Unfor­ tunately, until now all experimental results are not exclusive. Thus, wo attempted to reveal true mechanism of K-T event in terms of study on iridium species at K-T boundary, based on Ir chemical knowledge available.

The K-T boundary samples used in this work were taken from Fish Clay at Stevns Klint, Denmark, and Montana, USA. The former is marine sediment, while the lat­ ter is continent sediment. In addition, an ultrabasic rock from Xingjiang Province, the Ningqiang carbonaceous chondrite, the Baoxian county and Suizhou ordinary chondrites, and the Hawaii lava were also studied for comparison.

First, a new-developed phase separation procedure was used to divide geologi­ cal boundary samples into six phases, i.e. carbonate,Fe-Ni metal, sulfide, oxide, silicate and insoluble residue. The brief steps are as follows:

1. citric acid to dissolve carbonate phase, including other easily-soluble compo­ nents; 2. hydroxylamine to dissolve Fe-Ni metal phase; 3. saturated bromine water to dissolve sulfide phase; 4. HC1 to dissolve oxide phase; 5. hydrofluoric acid to dissolve silicate phase; 6. the remaining insoluble component is called HF-insoluble residue phase.

The Ir abundances in various phases of the K-T samples were determined by a ra­ diochemical NAA method based on a long-chain primary amine N1923 extraction, which can analyze Ir in geological materials as low as 10". g/g [1].

101 Table 1 lists the Ir abundances in 6 phases of two K-T samples. Our results indicate that about 50% of anomalous Ir are present in the HF-insoluble residue phase, no matter what the sediment is marine or continent. Recently, Schmitz, et. al. [2] reported 47% Ir in the HF-insoluble residue at Fish Clay, being in good agreement with ours.

Table 1 Ir abundance in various phases of K-T boundary clays at Fish Clay and Montana.

carbonate metal sulfide oxide silicate residue Fish clay(ppb) 2.23 31.6 - 9.1 6.6 162 (%) 4.0 21.5 0 9.4 12.0 54.5 Montana (ppb) 187 - - - 1.57 1S6 (%) 32.1 0 0 0 24.1 43.8

Moreover, we noticed that Ir does not exist in the sulfide phase of both K-T sam­ ples, which disfavors the geochemical enrichment of Ir. It, is because Ir accumulated by this geochemical process should exist as sulfide or soluble complex.

Ir is mainly, distributed in the sulfide phase in the ultrabasic rock sample, as a representative of the upper mantle material. The percent content of Ir in the HF-insoluble residue is as low as 5%, which is considerably different from that of the K-T samples. Furthermore, in the Hawaii lava, Ir mostly exists in oxide and silicate phases (>70%), while <10% in the HF-insoluble residue, which also greatly differs from the K-T samples. Our results indicate that the anomalous Ir at the K-T boundary samples does not come from the basic volcanic ash.

In contrast, the HF-insoluble residue and metal are main host phases of Ir for the Ningqiang carbonaceous chondrite, then followed by sulfide and oxide. However, for two ordinary chondrites, Suizhou and Baoxian county, Ir is mainly present in the metal and sulfide phases. The relative percent of Ir in the HF-insoluble residue phase is less than 5%. Our results imply that the extraterrestrial source matter could be carbonaceous chondrite, if the impact model is valid.

[1] Kong Ping and Chai Chifang, J. Radioanal. Nucl. Chem.,-130(19S9)321-331. [2J Schmitz, B., et al., Geochim. Cosmochim. Acta, 52(1988)229-236.

102 MEASUREMENT OF PROTON-INDUCED PROMPT LOW EN­ ERGY PHOTONS BY HIGH RESOLUTION SPECTROMETRY: THE ANALYSIS OF NOBLE METALS

Lotter Geoffrey Lackay; Dherendra Gihwala School of Science, Peninsula Technikon P 0 Box 1906, Bellville, 7535 South Africa

Max Peisach National Accelerator Centre P 0 Box 72, FAURE, 7131 South Africa

The processing of noble metal ores and refining of the metals re­ quire the use of accurate and rapid methods of analysis for which X-ray methods are well suited. Apart from L X-rays from noble metals, the use of Si(Li) detectors is inapplicable to the measure­ ment of other prompt photons because the detector efficiency be­ comes unacceptably low. Using HPGe detectors, the K X-rays and low energy gamma-rays from noble metals were measured under pro­ ton bombardment. The K X-rays are sufficiently resolved to enable individual elements to be determined without interference, while at the same time the detection efficiency for low energy gamma-rays is accepted even up to 200 KeV. Thus both X-rays and gamma-rays are available for the analytical determination of noble metals.

Excitation functions were measured for all analytically important prompt photons using protons from 1.8 to 5.8 MeV in steps of 0.2

MeV. From these excitation functions Em-values (see reference 1)

103 were calculated for use with thick samples.

Using the measured photon yields from pure metals, interference-free sensitivities were calculated as the concentration of the element nec­ essary to produce an integrated count equivalent to three times the standard deviation of the background against which it was measured.

The precision of the technique varied with the content of the metals in various matrices. Relative standard errors were from 1 to 4% at concentration ranges decreasing from 950 //g.g-1 to 100 /ig.g-1. The accuracy of the analytical method was acceptable and was deduced from the comparison between reported and found values.

[1] Ishii, K., Valladon, S., Sastri, S. and deBrun, J.L. Nucl. In- strum. Meth. 153(1987)503-507.

104 MICROPROVENANCE STUDIES OF ARCHAEOLOGICAL CERAMICS: A CASE STUDY FROM THE KANGAVAR AND MAHIDASHT VALLEYS, CENTRAL WESTERN IRAN

Louis D. Levine Royal Ontario Museum 100 Queen's Park Toronto, Ontario, Canada M5S 2C6

Provenance studies have long been used in a variety of ways to determine the sources of materials from which ancient objects were made, and to trace the flow of such materials over the landscape. They have not, however, been widely employed to address questions which could more properly be said to fall into the realm of microprovenance studies. Microprovenance studies focus on the distribution of ancient objects in the far smaller spaces of a single site, a valley, or a network of contiguous valleys, and often have more to do with questions of production and change through time than with the larger issues of trade which have been the focus of provenance studies for so long.

The investigation reported here centres on the INAA of a group of ceramics dating from the fourth millennium be which were excavated at two sites in the Kangavar valley, Godin Tepe and Sell Gabi, and one site in the Kermanshah valley, Tepe Siahbid. Both valleys are located in central western Iran. The sites of Seh Gabi and Tepe Siahbid were small villages Bites with economies based on subsistence farming. There is little reason to assume that we are dealing with either complex social organization or complex economies at either site. Godin Tepe is more difficult to characterize. During the later Bronze Age, it grew to become the predominant site in the valley, and this later deposit overlays and buries the Chalcolithic levels, which were only penetrated in small, deep soundings. Thus, the extent and complexity of the Chalcolithic settlement at Godin Tepe is unknown.

A total of approximately 450 samples of ceramics were selected from the three sites. They were choosen for the quality of their provenance - only samples found in deposits which could be characterized as representing primary and secondary contexts were selected, and for their intra- or intersite comparability. They were also choosen for their applicability to address specific questions in the areas of the social history or organization of the sites.

105. At the time of writing, the analyses of the data are still not complete. The samples are being run on a SLOWPOKE reactor at the University of Alberta, which allows for the quantitative assessment of over 35 elements. Once the samples are processed, the resultant information will be analyzed using data analysis techniques such are described in Vitali et al. HJ. In thiB inscance, however, some of the questions that will be addressed using these techniques include :

can assemblages of different pottery types from different houses in an ancient village be distinguished chemically, and what are the implications of their being distinguishable or not?

can ceramic production be seen to be a specialized , centrally located activity, and can this be correlated with site size and complexity?

do the clear ceramic traditions which are reflected over time also reflect continuities in the technical process of manufacture which can be demonstrated chemically?

The paper will explore issues such as these.

[1] V.Vitali, J.W. Simmons, E.F. Henrickson, L.D. Levine and R.G.V. Hancock, Journal of Archaeological Science, 14(1987) 423-435.

106 APPLICATION OF NAA IN ANALYSIS OF SEDIMENTARY ENVIRONMENTS IN SHALLOW SEA

Li Guodong,Tong Chunhan Institute of Applied Nuclear Technigue Chengdu College of Geology,China

Environment of sedimentation is an important part of contents of sedimentology,which is significant theoretically and practically for knowing paleogeographic charicteristics and the evolution of geological history of the earth surface and directing geological investigation and search for ores,Because of the polykeys of conventional penological, paleobiological and paleoecological methods and marks,researchers have been trying to seek more methods. Therefore, the geochemical method has been developed. Distinguishing between marine sediment and continenal deposit acording to B,Sr,Ba,Ga,Br,Cl has been performed successfully. But few elemental marks of micro-environments in an ocean or a continent marks of micro-environments in an ocean or a continent have been studied. At the same time, many trace elements with important environment significance almost have not been researched because that mordern analytical techniques have been employed little.

In this study, more than 30 elements in carbonate rock in the early palaeozonic shallow sea,north China, have been studied and more than 20reliable marker elements have been found.

Carbonate rock has the feature of high Ca and very low trace element concentrations. To detect as many elements as possible and reveal the small difference in trace element concentrations in defferent sedimental environments, the advantage experimental conditions have to be selected.Thus,a large integral neutron flux, large sample weight, short cooling time and long collection time were adopted,and epithermal neutron activation was used.

107 Under the condetions,Na,Mg,K,Ca,Ti,Fe,La,Ce,Nd,Sm,Eu,TbsYb. Lu, As, CI, Br,Rb,Sr,Cs,Ba,Hf,Ta,Co,Ni,Zn,Sb,Sc,V,Cr,Mn5U,Th could be determined,and the detection limits of most elements reached 0.001-O.lppm level.

The following elements are related closely with the sedimentary environments: 1. The concentrations of Al, Sc,Cr,Fe,Sb,Th,Hf,Co,Rb,As,Lu decrease in the supratidal zone iniertidal zone sublittoral zone order,but increase in the open sea (Tab.l).

Tab.l Concentrations of some elements in carbonate rock in shallow sea environments ppm Environment Al% Fe% Sc Cr Sb Th U Ta Ba Supratidal 0.85 1.66 1.40 8.4 0.2 2.0 13 0.13 11.5 Intertidal 0.30 1.32 0.58 3.2 0.1 0.7 4.0 0.05 40 Sublittoral 0.09 0.07 0.20 1.1 0.02 0.2 2.6 0.03 20 Open sea 0.13 0.08 0.35 1.8 0.05 0.4 2.1 <0.02 8

Al Is a marker element of terrigenous scraps,its destribution depends on the diostribution of the scraps.ScJCr,Fe,Sb,Th,Hf,Co, Rb, As and so on, existing in the scrapminerals in isomorphous form,distribute similarly with Al. 2. Ta,U,V,Ba,Ti, Cs and so on decrease sequentially in the supratidal zone—intertidal zone—sublittoral zone—open sea order(Tab.l), which is because of the chemical sedimentation in the shallow sea.

The computer discriminatory analysis showed that the elements above are remarkable destinguishing marks of the environments, and established the descriminat functions.The discriminat results of 17 unknown samples agree well with the actual geological conditions.

.108 SOME ASPECTS OF RADIOANALYTICAL CHEMISTRY OF

196>19SAUj »2Ir)186ReAND 96Tc

Li Yinming Ding Yuzheng Sun Xiaozhong Northwest Institite of Nuclear Technology P.O. Box 69 Xian,China

The fractionation behaviour of 196,198Au ,192Ir ,185Re and 96Tc in fallout sam­ ples and sample—decomposition methods have been studied in order to devel­ op the analytical method for determination the total yield of these nuclides in debris. Our results indicated that in fallout particles Au exists as dispersed ele­ mental state, the chemical state of Ir is Ir02, while Re and Tc exist as oxides or oxacids.

As a result of tracer-labelling experiments, it is concluded that Na20:; melting method can be used for decomposition the fallout particles and soil samples without the volatilization loss of Au, Ir, Re and Tc, but in case of analysis of 1%'198Au in samples with filter material , wet ashing or radiofrequency low temperature decomposition method are preferable.

I96,I98 I92 186 Owing to the quite different fractionation behaviour of Au 5 Ir , Re and 96Tc with other nuclides, the total yield of these nuclides canot be evalu­ ated by determination the ratio of the number of induced nuclide to the num­ ber of a fission product or a fissile nuclide. Therefore, a reactivation method is proposed for solving this problem.

109 EFFECT OF CASCADE COINCIDENCES ON THE EFFICIENCY CALIBRATION OF A GAMMA-X DETECTOR

Lin Xilei' and K. Heydorn Isotope Division, Ris0 National Laboratory DK-4000 Roskilde, Denmark

The absolute full-energy peak efficiency (EP) is an essen­ tial parameter in work related to the absolute evaluation of gamma-ray intensities. This is also true in neutron

activation analysis that relies on the absolute or the k0- standardization method. e„ may be determined by means of radioactive standard point sources with single or multiple gamma energies covering the range of interest. Cascade co­ incidence effects may be avoided by counting 15 cm or more from the detector. The efficiency of actual samples measured at positions closer to the detector may be eval­ uated by a semiempirical method under certain conditions [1]. Often there is no way to calculate the efficiency accurately, and the £p has to be determined by means of standard sources with the same geometry and similar main components as the actual sample.

For p-type gamma-ray detectors with an aluminium end-cap and a dead-layer of germanium crystal facing the radio­ active sources, single gamma-lines are useful for calibra­ tion also close to the detector. Many such sources use electron-capture nuclides, which decay to an excited level and emit a cascade of low-energy K X-rays with the gamma- ray; in practice they are coincidence-free, because the efficiency of such detectors at less than 50 keV drops sharply with decreasing photon energy. *On leave from: General Research Institute for Non-ferrous Metals, Beijing, China 110 For n-type garama-X detectors the situation is different. Even single gamma-ray standard sources cannot always be assumed to be coincidence-free, due to the much higher efficiency for X-rays, resulting in gamma-X coincidence effects when counting close to the detector.

This work includes combinations of cascade coincidences between gamma-rays, X-rays, 511 keV annihilation radiation, as well as J5-radiation and its associated bremsstrahlung. The following radionuclides 22Na, 51Cr, MMn, "Co, 60Co, 65Zn, a5Sr, 8flY, 109Cd, 113Sn, 137Cs, 139Ce, 203Hg, and 241Am, which are frequently used in ep-calibration, were scrutinized for potential cascade coincidences, and practical corrections were calculated.

A gamma-X detector with a relative efficiency of 37 % was calibrated with these 14 nuclides in 1 cm3 aqueous so­ lutions in half-dram polyethylene containers at 11 separate positions, at distances from 0.88 cm to 17.5 cm, with and without a perspex il-absorber between the detector and the sample. In order to perform coincidence corrections, peak to total ratios were determined by means of 2,1Am, 109Cd, "Co, 51Cr, 137Cs, 203Hg, and 65Zn sources.

After correcting for coincidences, smooth Ep-curves were obtained even for the position closest to the detector. Maximum efficiency was found for energies of 60-100 keV. Photons with energy down to 15 keV were detectable only without any perspex absorber.

[1] Moens, L., De Donder, J., Lin, Xilei, De Corte, F., Hoste, J., Nucl. Instrum. and Methods, 187 (1981) 451.

ill A ?RSIRRADIATION SEPARATION PROCEDURE FOR GALLIUM DETERMINATION IN BIOLOGICAL AND ENVIRONMENTAL MATERIALS M NEUTRON ACTIVATION ANALYSIS LIN Xilei*, M. Speziali and E. Orvini CiJR Center for Radiochemistry and Activation Analysis, Viale Taramelli, 12, 27100 .Pavia, Italy. Gallium is an element of increasing biological interest: it is involved in problems related to environmental pollution (Ga compounds are used in the electronics industry) and to clinical treatments (Ga radionuclides are employed to detect and to treat neoplastic lesions)[l, 2, 3]. Efforts have been made in recent years to develop analytical methods capable of measuring nanogram levels of gallium in different types of materials. Neutron activation analysis (NAA) conventionaly with post- irradiation radiochemical separations is a sensitive method to determine trace amounts of gallium; unfortunately, dealing with biological samples, the analyst is required to handle highly radioactive samples, owing to their high sodium and potassium contents. The radioactive hazard makes it a difficult (if not impossible) task to determine gallium • routinely. Developing a preirradiation procedure emerges in this case as an alternative to "eliminate the radiation risk while taking the advantages of high sensitivity of NAA.

In this work, a simple but specific preirradiation procedure, based on ion-exchange chromatography, for gallium determination in biological and environmental materials, is reported. The sample was digested with concentrated HN03 in teflon- lined high pressure dissolution vessel. The resulting solution was diluted with deionized water and passed through a cation exchanger column. The affinity of the cation exchanger for metal ions generally increases with the magnitude of the charge on the ions; consequently, the separation of Ga3+ from the main interfering ions Na+ and K+ in HN03 media was very effective. The gallium retained on the column was eluted by diluted HF directly into an irradiation vial which was submitted to irradiation and then to gamma-ray spectrometry. The single comparator method was employed for the gallium quantitative evaluation. '•"On leave from: The General Research Institute for Non- ferrous Metals, Beijing, China

112 The reliability of the proposed method was extensively investigated. The gallium recovery of the entire procedure was proved to be higher than 98.5 % , both by tracer experiments and analysis of spiked samples. The analytical results on gallium determination in Coal Fly Ash (NBS SRM 1633a), obtained in this work by, respectively, instrumental NAA and the proposed method, were in excellent agreement each other and also consistent with values reported in the literature. The gallium concentration in Bowen's Kale obtained in this work is in good agreement with literature data. The proposed method was also applied to gallium determination in Orchard Leaves (NBS SRM 1571); the results obtained using samples of different weights (100 mg and 500 mg) were in good agreement. The detection limit of the method was found to be 88 pg of Ga. Usually, NAA with any preirradiation treatments is inherently linked with the possibility of contamination and with the blank problem. In the actual case, for gallium determination, the drawback was proved to be of minor importance. After purification of the cation exchanger, the gallium blank of the entire procedure, carried out under normal laboratory conditions, was found to be 0.34 ng, mainly coming from the concentrated HN03 used in sample digestion. Five materials, the three mentioned above plus Olea Europaea (BCR CRM 062) and Bovine Liver (BCR CRM 185A), with gallium contents at different levels ranging from ppm to a few ppb, were analyzed. It would be interesting to mention that the gallium analytical result for Orchard Leaves (NBS SRM 1571) obtained in this work (122 ± 6.3 ppb) is substantially higher than any published values (78 - 89 ppb) which have been adopted to demonstrate an analytical procedure. Our result seems to be more accurate, due to the careful examination on the reliability of the proposed method. [1] Hart, M.M., and Adamson, R.H., Proc. Nat. Acad. Sci. USA, 68(7) (1971) 1623-1626. [2] Tarasenka.N.Y., and Fadeer, A.I., Gig. Sanit., 10 (1980) 13 [3] Speziali, M., Orvini, E., Rizz.io, E., Giordano, R., and Zatta, P., Biol. Trace El. Res., 22 (1989) in press.

113 Thn Metabolism of Titanium and other Elements in Mister Rat

Liu NianQing, Zhang Xiaofeng, Feng Songlin, Zhong Ming, Yan Linna I HEP Aeademia Sinica, Beijing, P. R. China Ji Yunj.ing, Wangming, Li JianHua, Jin Feng Beijing Institute of Labour Hygiene and Occupation Diseases

Vitamin C-Titanium (Ve-Ti) as a. additive for animal feed and plants (frui ts and crop so on} fertilizers is used more and more in order to improve and obtain the better and more food for human. Therefore, information of titanium metabolism is of i rite ret. t.ing[l , 2]. Titanium metabolism was measured in nine Wist cor rata. Three of male rats (250-300g) were dosed orally with fJOOOmg/Ug body weight, using the solution of Vc-Ti 50mg/inl. Three oral male rats (250-300g) wore dosed intravenous with 50mg/kg body weight, using the solution of Vc-Ti .10mg/ml, three of female were dosed in same way using the solution of Vc-Ti iOmg/ml mixed with FeS04 2mg/ml. The components of Vc-Ti are 15.2% Ti, 45% Vc and 27.6% CI. The contents of titanium and other elements in blood samples were determinated by PIXE, in organs by PIXE and spectrophotometry.' The concentration of feces and urine were analyzed by spectrophotometry. In figure 1 shows that following intravenous injection of rats, titanium absorption and clearance in blood could be described by an exponential equation of three terms: ( 0.324 ug/ml, 0.0159/hr; 1.05ug/ml, 0.270/hr; 3. lOug/ml , 2. 45/hr ). After intravenous dosing, at J. 1.5 hr the absorption of Ti. from blond have had 9r>% of the administered , at 196 hr clearance of the intravenous dose from blood have finished about 95% as calculated by pharmacokinetics model[3]. In table 1 describes after intravenous abministration the distribution of titanium in organ with different time . After intravenous dosing, at 168 hr the total Ti content of organs have accounted 90% of dosing. In the figure 2, after oral dosing the excx-etion from feces indicates that the accumulate percentage of it was 70-80% of titanium with 72hr and the main excretion was not from urine. The re] at ions of other elements content (Ca, Fe, Cu, Zn, P, K) with time in blood after intravenous administration were obtained simultaneous with the measuring titanium. The result reveals that the content of calcium in blood with time is increasing (particular in female group) ; the concentrations of elements Fe and K are decreasing; and the contents of elements Cu and Zn are significantly fluctuating in both male and female groups. However, the changes of all above situation except element Ca in femaio group are more smooth and smaller than in male. All of these could implicate the antagonist! action between elements and Ti ( or Fe), and the synergetio action between Ca and Ti. (or Fe). We need further study to demonstrate above results. 114 Title 1. Coccentrations of Ti in specific organs after intravenous adainistrttion in different tiie. Unit:pps. [wet weight)

Tiie Heart Liver Spleen Lung Kidney Stoiach Intestine Testis Muscle Brain

Ehr 7.85 4(.94 3.90 16.07 11.96 1.78 3.01 .0.59 (.41 0.16 (0.87) (1.40) (0.69) (5.76) (3.75) (0.57) (0.43) (CO) (1.42) (0.0)

24hr 7.63 43.29 8.35 6.60 15.07 1.05 3.64 0.91 4.44 0.93 (1.89) (14.34) (1.32) (1.87) (1.70) (0.36) (0.53) (0.06) (0.81) (0.15)

3day 7.54 35.94 12.99 4.6E 17.61 2.78 (.19 0.96 (.61 1.31 (0.59) (2.90) (2.12) (0.40) (2.49) (1.05) (0.20) (o.:n) (0.45) (1.04)

7day 3.20 19.66 25.94 3.88 26.49 6.07 3.68 1.47 5.18 2.01 (1.60) (3.22) (2.08) (1.05) (4.02) (1.50) (0.43) (0.72) JO.27) (0.67) tncte: The neuter in blanket iE the standard deviation of the data.

G.83S.

3i.M8~ 24.9 72.9 129.9 1M.9 211.9 2(4.9 h* S4.9 193.9 1:2.9 2S1.9 259.9 Hiwtt

Figure 1. Regression of blood Ti Figure 2. Excretion fro* feces concentration as a function of tiie ( accuaulate preccnt ) after oral after intravenous administration adiinistration to rats to rats

References:

1. G. Kazantzis Role of Cobalt, Iron, Lead, Manganese, Mercury, Platinum, Selenium and Titanium in Carcinogenesis. Enviromental Health Prespectrives. 1981. Vol 40. P143-161 2. Handbook on the Toxicology of Metals, Vol. II, Chapter 24, Titanium Editors. L. Friberg, G.F. Nordberg et al. 1986. 3. M. Glbaldi, D. Perrier Pharmacokinetics Marcel Dekker, 1975.

115 AN ON-LINE THERMAL NEUTRON PROMPT GAMMA MEASUREMENT SYSTEM FOR BULK DETERMINATION OF AL AND FE IN METAL ORES

Liu Yuren1 and Seymour, R.S.2 1 Henan Joint Center for the Development of Industrial Application of Nuclear Instruments, P R C 2 EG&G ORTEC, 100 Midland Road, Oak Ridge, TN USA 37830

The development of an on-line analyzer for the measurement of elemental Al and Fe in metallic ores permits high accuracy determination of these elements in a real-time industrial environment. This paper discusses the data acquistion and analysis measurement system and some of the limitations to the accuracy of this measurement.

The analysis system was developed jointly by a Sino-American cooperative program. EG&G ORTEC provided a high-count rate, high resolution gamma-ray spectroscopy analysis system. The Henan Joint Center provided the Cf isotopic neutron source, source shielding, sampling apparatus, and application software.

The sample irradiation assembly consists of a 200 /jg of 252Cf in a concrete shield containing a down-looking vertical tube. A hoist lowers the source down the vertical tube out of the source shield and into a special container with a concentric plastic cylinder. This geometry allows the neutron source to be placed into the center of the sample container without being in direct contact with the sample. A borated paraffin inner shield around the sample absorbs any stray neutrons to reduce the external neutron flux. This inner shield is surrounded by a concrete outer shield to further reduce the neutron flux outside the measurement system. Below the source is a Bi plug to absorb any neutrons in the path of the n-type HPGe detector. The uniform sample and irradiation geometry are critical for accurate and precise measurements. The sample heterogeneity and geometry limit the obtainable accuracy.

The data acquisition and analysis system consists of a large volume (30% rel. eff.) n-type HPGe detector with a transistor reset preamplifier. The detector and preamplifier are capable of throughput rates in excess of 800 GeV/sec. An EG&G ORTEC model 673 Gated Integrator Amplifier with a shaping time of 0.25 /is was used in the acquisition of data to provide maximum throughput with minimal pile-up. Most pulse pile-up resulted from the 2.2 MeV prompt gamma of hydrogen from the water matrix of the sample. Pulse pile-up results in a distortion of the spectrum at higher energies and is the chief limitation to sensitivity for this measurement.

The amplifier output is then presented to a model 918A multi-channel buffer which contains a 10 lis fixed conversion time ADC and an 8000 channel data memory. A model 990 digital stabilizer keeps the zero and gain stabilization to within 1 channel regardless of fluctuations of the input count rate. Digital stabilization ensures that differing count rates during calibration and varying sample compositions will not result in gain shifts and hence simplifies the analysis of the data.

Data are analysed by summing the net counts in the single and double escape peaks (SEP.DEP) with the net counts in the full energy photopeak (FEP). At these energies, pair production is the dominant mode of gamma-ray electron interaction. The required accuracy is obtained in reasonable counting times by summing the counts in all of these peaks. Because of pulse pile- up and incomplete energy deposition in the detector, the background under the three peaks is about 50% of the DEP gross counts, 30% of the SEP gross counts, and 10% of the FEP gross counts.

Future systems will incorporate newer analyzer designs capable of even greater throughput by using a faster ADC (7 [is). These systems will also incoporate a digital stabilizer and will have 16000 channels of data memory to permit viewing of a wider energy range. Other improvements

116 include larger n-type detectors which are neutron damage repairable on-site. The ability to repair the detector on-site, overnight will minimize downtime of the system. Anti-coincident gating of the HPGe detector using a guard detector to suppress any events counted in both detectors may also improve sensitivity in future systems.

This first system will be used in an alumina production mill to perform on-line analysis of Al in raw alumina pulp. The range of elemental compositions found in the pulp and the measurment error, which is the relative accuracy of the measurement, for a number of useful elements are presented in table 1.

Table 1.

Oxide Concentration Ranae (%) Measurement Error (%) AIA 10-40 ±0.3 Fe203 1 -10 ±0.1 CaO 10-30 ± 0.4 Si02 5-20 ±0.4 Na20 10-30 ±0.4 Ti02 < 5.5 + 0.2 H20 10 -100 ±0.5

Facilitation of this measurement at Al plants is expected to reduce plant costs by over 3 million dollars through reduced energy consumption, more rapid qualification of pulps being mixed during the production process and in savings of labor.

The equipment has been tested on-site at both the Shandong and Zhengzhou Aluminum Works. Our preliminary on-site measurements confirm the stability and reliability of the equipment in an industrial environment. The measurement errors obtained on-site for elements within the concentration ranges are consistent with the laboratory measurements.

117 SOLVENT EXTRACTION OF DITHIOCARBAMATES COMPLEXES AND BACK- EXTRACTION WITH PALLADIUM(II) FOR DETERMINATION OF TRACE METALS IN SEAWATER BY NEUTRON ACTIVATION ANALYSIS

Jem-Mau Lo, Yeu-Ping Lin and Chia-Cheng Cheng Institute of Nuclear Science, National Tsing Hua University Hsinchu 30043, Taiwan, China

Neutron activation analysis is one of the preferred methods of determining trace metals in environmental or biological matrices. However, a purely instrumental neutron activation analysis technique is not feasible for the natural water samples, because the metals of interest may be present at low concentrations and, consequently, in the gamma-ray measurement the activity of the product nuclides of interest will be obscured by the presence of high activity of major elements such as Na, K and Br. To obviate this difficulty, chemical separation before and/or after irradiation must be employed. An application of preconcentration technique is preferable for water analysis to reduce the sample volume. In this study, a two-step preconcentration procedure is proposed to couple v/ith neutron activation analysis for the determination of trace metals in seawater including Hg, Cu, Ni, Cd, Co and Zn.

The two-step preconcentration procedure involves extraction of the trace metals from seawater (pH 4.5 adjusted) with dithiocarbamate (using a mixture of sodium dithiocarbamate and ammonium pyrrolidinedithiocarbamate) into chloroform followed by backextraction with a Pd(II) aqueous solution (pH 1, HNO~). Usually a large excess quantity of the extractant, dithiocarbamate (i.e., >_ 100-fold) was added to

118 profitably react with the trace amounts of metals in sea- water [1]. The extraction procedure would concentrate the trace metals with characteristics of forming complexes with dithiocarbamate with a high enrichment factor as with a large volume ratio of the seawater to the organic solution. The major matrix material, the alkali, alkaline earth and halogen elements which do not react with dithiocarbamate would remain in the aqueous solution. Subsequently the organic phase was separated and washed by a pH 12 water solution to remove a considerable amount of dithiocarbamic acid present, possible due to the formation of H ion with dithiocarbamate during extraction. Otherwise, the present dithiocarbamic acid would seriously consume Pd(II) used for the backextraction agent. Thereafter a small amount of Pd(II) was added to backextract all of the metals in organic phase into the aqueous solution. The backextrac- tion agent Pd(II) was selected owing to the extraction constant of palladium dithiocarbamate being the largest and much higher than most of the other metal dithiocarba- mates [2-5]. Based on this fact, the metals in the complex forms in organic solution were readily substituted by Pd(II) and transferred into the aqueous solution. The enrichment factor was further increased at the backextrac­ tion step as with a large volume ratio of the organic solution to the Pd(II) solution. Finally, the aqueous solution containing simply the enriched metals and some of nonreacted Pd(II) was taken for neutron activation analysis.

The gamma spectrum of the preconcentrated solution after neutron irradiation showed clearly the radiations from the metals of interest. Bulk amounts of Na and Br were removed from the sample by the preconcentratipn procedure as indicated from the spectrum. Palladium was also activated but the produced nuclide, 109 Pd is short-lived (tj=13.47 h)

119 and decays to Ag (t,=39.2 s), emitting a very low-energy gamma-ray (i.e., 88 keV) which does not interfere the gamma- spectrum of the metals of interest.

[1] Lo, J.M., Yu, J.C., Hutchison, F.I. and Wai, CM., Anal. Chem., 54 (1982) 2536-2539. [2] Briscoe, G.B. and Humphries, S., Talanta, 16 (1969) 1403-1419. [3] Yeh, S.J., Lo, J.M. and Shen, L.H., Anal. Chem., 52 (1980) 528-531. [4] Shen, L.H., Yeh, S.J. and Lo, J.M., Anal. Chem., 52 (1980) 1882-1885. [5] Lo, J.M., Shen, L.H. and Yeh, S.J., J. Radioanal. Nucl. Chem.-Articles, 88 (1985) 313-323.

120 TRACE ELEMENT DETERMINATION IN AEROSOLS FROM THE ANTARCTIC PENINSULA BY NEUTRON ACTIVATION ANALYSIS*

A.L.M.Loureirov , M.B.A. Vasconcellos^ , E.B.Pereira'' ; (1) Brazilian Nuclear Energy Commission - Nuclear and Energy.Research Institute (IPEN-CNEN/SP) P.O.Box 11049, CEP 05499, Sao Paulo-Brazil

(2) Institute of Spatial Research (INPE) P.O.Box 515, CEP 12200, Sao Jose dos Campos-Brazil

* Grant from the Brazilian Antarctic Program N9 9586

Recently interest has grown in the determination of the composition or atmospheric aerosols in remote areas, like the South Pole and tha Antarctic Peninsula O-*O • This knowledge is of great important for the study of long-range transport of atmospheric contaminants and fro:;i the clitnatological point of view also.

Due to the very low elemental concentrations foimd in remote areas, only verysensitive analytical techniques, like neutron activation analysisL3,4D , PIXE, AAS , ICP-AS, can be applied.

The present work is a joint project carried out by the Institute of Spatial Research (INPE) and the Nuclear and Energy Research Institute (IPEN-CNEN/SP) for the analysis of several trace elements in the atir.O£ phare of the Antarctic Peninsula. The Brazilian Antarctic Station "Comandante Ferraz" (62°S , 58?W) where the samples were collected is located on the King George Island in the Antarctic Peninsula and is maintained by the Brazilian Antarctic Program since 1984.

Aerosol samples were collected from a 5 meter tower at the external part of the Laboratory of Atmospheric Sciences of the Station. The collecting system is very simple and consists of a membrane pump surrounded by a PVC protector, to avoid the penetration of snow or ice. Air is aspirated through a Millipora filter, of 0,45 um pore size and 18 mm diameter. The filter is placed on a screen in a plastic holder. The flow rate of the pump is of 0,25 m3/h and air is collected for a period of one week. The filters were first analyzed for their alpha radioactivity and then irradiated for instrumental neutron activation analysis.

Irradiations were carried out at the IEA-R1 research reactor, under a thermal neutron flux of about 1012 n.cm~2»s~1. Filters and synthetic standards were encapsulated in polyethylene envelopes and placed in polyethylene or aluminum irradiation containers. Irradiations of five minutes allow the determination of Al, V, Mri, Ma and CI and of

121 24 hours allow the determination of Ca, Au, Br, Sb, Sc, Fe, Zn, K and La. Blanks consisting of clean Millipore filters and plastic envelopes were analyzed and the concentrations of the elements found in the blanks were subtracted from the real samples.

Radioactivity measurements were carried out by using an ORTEC Ge(Li) detector with a resolution of 2.7 keV for the 1332 keV peak of 60Co coupled to an ORTEC Model 6240B, 4096-channel analyzer. Calculations were performed with a PDP 11/04 computer by means of the GELIGAM software of ORTEC.

The accuracy of the analytical technique was tested by analyzing the elements of interest in the reference materials W-l (USGS) and Bowen's Kale. Good agreement was found with the literature values.

The aerosol elemental concentrations were determined in 86 samples collected at the Brazilian Station, during 1986 and 1987.

Concentrations found, after subtracting the blank, were of the order of ng/m3 for V, Al, Mn, Na, Cl, Ca, Br, Fe, Zn and K, and of the order of pg/m3 for Au, Sb, Sc and La.

The data obtained are being processed by Principal Factor Analysis, using IBM/PC compatible software. Correlations with other measurements performed at Ferraz such as radon, ozone, CO, and meteorological data are also being made by use of this software.

The concentrations found for V, Al, Mn, Na and Cl allowed to draw the following preliminary conclusions: -The elemental concentrations present a seasonal variation. - The marine aerosol is predominant. The Na/Cl of 1,8 found is consistent with the ratio found in seawater. - Principal factor analysis points to two factors to explain the origin of these elements, which are the ocean and soil.

The data for Ca, Br, Fe, Zn, K, Au, Sb, Sc and La are being processed.

CljDick, A.L., Peel, D.A. , Annals of Glaciology, 7 (1985) 12-19. C2J Cunningham, W.C., Zoller, W.H., Journal of Aerosol Science, 12 (1981) 367-384. I_3j Maenhaut, W. , Zoller, W.H., Journal of Radioanalytical Chemistry, 37 (1977) 637-650. Koyama, M., Takada, J., Kamiyama, K. , Fujii, N., Inoue, J., Issiki, K., Nakayama, E. Journal of Radioanalytical and Nuclear Chemistry, Articles, 124 (1988) 235-249.

122 Determ'mat ion of Rnre-EaTth Elements In Hi yh•Pure Yttrium Oxide By Neutron Activation Analysis

Lu Hui Juan Zhou Yun Lu Beijing General Research Institute Of Non-ferrous Metal J •

The method takes advantage of separating rare-earth elements by P507 extraction chromatography,preconcentrating rare-earth impurities in yttrium oxide and combines with instrument neutron activation analysis, La, Ce, Pr, Sra, Eu, Gd, Tb, Tm, Yb and Ln in high purity yttrium oxide are determined.'

The method is divided into two parts, namely, one. is preconcentration measurement of La,Ce,Pr and Sra.The other is direct measurement of Ce,Eu,Rd, Tb, Tni, Yb and Lu by y -spectrum system.Preconcent ration makes use of P507 extraction chromatography.The decontamination factor of yttrium can reach 2X 10*,Chromatographic columns can be reclaimed 1o use many times. The method is simple,reliable and quick(about 70 minutes for preconcentrat ion) and suitable for determining high-pure Y,0, of 99.99992ft. The lower limit of detection are given as follows,U,0. 02;Ce, 0.05 jPr, 2-. Sra, 0.003( Eu, 0.1)05 ;•

Gd, 0.2,Tb, 0.003 ;Tm, 0.04;Yb, 0. 4;Lu, 0.3.

The results are listed in table 1 and 2 respectively.

Table 1 Determination of La, Ce, Pr and Sm in high-pure yttrium oxide by prctreatraenl method (PPm)

| Name/Elements j La | Ce j Pr i Sm |

I Y,0, 070603 | 0.120 | - | I 0.0475 |

I 9-3 | 0.159 | 3.99 | 9.62 I 0.103 j

| 9-6 | 0.202 | 7.29 ! 15.0 | 0.113 |

123 Tahin 2 Determination of ("e, Eu, Gd, Tli, Tni, Yli ami Lu in h i yh pure Y^O., hy instrumen I method (PPnO

•"••"i | Name. Elements | Ce j liu Gd Tl. Tin VI) Lu T 3.08 | 0.0439 ( 0.497 | 20. | 0.11)4 | 1.40 if).

| 8.27 | 0.0417 I 0.550 | 20.6 | 0. 163 I 1.51 \ 0. 447 h —H f- -]• I 5# i 'i4.1 3 i II.U338 | • | !0.S I I 1.43 0. 397

I 10* i 4.17 i 0.0429 ! 0.594 | 10.2 | •• ,' 1.17 \ 0 391 h • t - -I H i i 1- - | Matrix ! 0.0826 | t).01U6 ! 0.301 \ 0.199 | 0.23B | 1.18 I). 196

1. Peng Chun Liu Anal cheni 9(0) 278(1981) 2. Lu An Qiu Anal chew 7(2) 97(1979)

124 THE SYSTEMATIC SEPARATION AND RADIOCHEMICAL DETERMI­ NATION METHOD FOR NEUTRON ACTIVATED NUCLIDES AND SOME ACTINIDES

Lu Zhaoda Li Yinming Qian Ruisheng Chen Da Chang Yongfu Northwest Institute of Nuclear Technology P. O. Box 69, Xian, China

The neutrons released by nuclear explosion can induce the activation of environmental substances and produce radioactive nuclides. Sometimes, it is necessary to determine the yield of these nuclides quantitatively. The nondestructive measurement of these nuclides by Ge(Li) spectrometry is im­ possible because the radioactivity of them is of the order of a hundred thou­ sandth of the radioactivity of fission products. Therefore, a systematic separa­ tion procedure has been developed for the isolation of Sc, Co, Ni, Rb, Nb, Y, Tb, Tm, Lu, Hf, Ta, Ir, Au, U, Pu, Am and Cm in environmental sam­ ples.

The nuclides mentioned above are separated into seven groups: 1) noble met­ als (Au, Ir, W); 2) alkaline metals ( Rb,Cs ); 3) Sc and heavy lanthanides; 4)Co, Ni; 5) Zr, Hf; 6) Nb , Ta ; 7) actinides. After group separa­ tion, high selective procedures have been used in order to separation the nuclides within the group and further decontamination of the radioactivity of fission products.

The purified radioactive sources of nuclides was determined by y —spectrometry, a - spectrometry or liquid scintillation counting. The accuracy of determination for different nuclides is within the range of ± 1%— ±5%.

125 . AN EXPERT SYSTEM FOR NEUTRON ACTIVATION ANALYSIS

Ma Jianguo, Sun Jianguo Institute of High Energy Physics, Academia Sinica P.O.Box 2732, Beijing, China

As an element analysis technique, the neutron activation analysis (NAA) method has been now developed very well. A large number of data are being produced out by it. In spite of some large softwares' having existed, such as the various programs for the spectrum analysis, APCP for the experiment prediction, etc., a synthetic multi-function system for data process in NAA is urgently needed. To simplify the data process, improve the analytical quality, optimize the experimental conditions and accumulate the experimental data, an expert system for neutron activation analysis has been designed on the personal computer, Great Wall 0520Ch.

This system is composed of three subsystems which are the spectrum analyzing process, optimization of the experiment conditions and a data bank. By the first subsystem, the gamma spectra from multiple channel analyzer can be treated conveniently with regular methods and/or intellectualized isotope identification based on a professional knowledge library which can be modified easily. A program for quality control will be created for the users to confirm'their results from the system. Some mistakes in the measurement or in the analyzing process may be point out and suggestions for correcting them will be available. The final results of elemental concentrations can be saved into the data library directly. By the second subsystem, the gamma spectrum of a type-known sample can be predicted or simulated. It is very useful for the experiment design or for the preparation of standard materials. The optimum experimental conditions can be also calculated in the subsystem by a target function concerned with the sample type or elemental component, flux of neutron during irradiation, as well as the cost on irradiation and measurement, and so on. For some special elements which may be difficult to be determined with routine methods, this subsystem will show some special methods or suggestions to the users . With the last subsystem, the data library for neutron activation analysis will be established. The data of elemental contents in various samples from the experiments or from published papers will be saved into the library for data accumulation and statistical calculation. The rough frame of the system and the functions of the subsystems are shown in figure 1.

126 THE EXPERT SYSTEM FOR NEUTRON ACTIVATION ANALYSIS

SUBSYSTEM 1 SUBSYSTEM 2 SUBSYSTEM 3 Object: Object: Object: Treat gamma spectra Prediction and Data bases automatically and optimization for Functions: intelligently. experiment design. l.Data accumulation Functions: Functions: 2.1nquiry. 1.Regular analyses. 1.Simulate a gamma 3.Statistical ana­ 2.1ntellectualized spectrum with a lyzing process. isotope identifi­ set of experiment 4.Common mathema­ cation. parameters. tical process. 3.Corrections for 2.Optimize the unsolvable peaks, experiment para­ dead-time and meters. decay time. 3.Give suggestions 4.calculation for for the experiment element contents. of a sample or of 5.Correction for some elements. interfered nuclear reactions. 6.Check results for the quality control.

Figure 1. Frame of the expert system for neutron activation analysis and the functions of its subsystems.

The expert system for neutron activation analysis is being written in the computer language C, FORTRAN 77 and BASIC.

127 . A STUDY OF THE SEDIMENT MOVEMENT WITH THE METHOD OF NEUTRON ACTIVATION ANALYSIS

Mao Zhixiang, Yan Pcilan, Huang Jlanwcl and Dal Xiankal (Nanjing Hydraulic Research Institute, Ministry of Water Resources, Ministry of Communications, Ministry of Energy, P, R. C.) Chai Zhifang, Qian Qinfang and Ma Jianguo (Institute of High Energy Physics, Acadcmia Sinica)

This paper presents a method of study on the sediment movement by means of Neutron Activation Analysis (NAA) with the natural sediments.

In the planning of hydraulic engineering such as the regulation of the estuary, dredging of the chan­ nel, selection of the harbour site, design of the breakwater etc., the most important problem of re­ search work is about the sources, transportation and deposition of the natural sediments. Generally, the movement of the natural sediments could be observed in field with a tracer or the method of trac­ ing, in which elements of mineral, fluorsccnccr, radioactive isotope, and NAA arc included, but each of these tracers (or methods) has its advantages, disadvantages and suitable condition. For example, the tracer of radioactive isotope can be used to a certain limited condition, because its ray will be harmful to the health of every person and the environment around the ray be polluted, in order to avoid this fatal shortage, some scientific researchers began to try the method of NAA to study the sediment movement from 1970.

There arc two ways of working with the method of NAA to observe the movement of the sediment, one is that tracers arc added to the field, the other is that the movements of the natural sediments arc directly observed and analyzed. The latter is based on that the contents of the microelements cm- beded in the natural sediments arc obviously different from the various sources and districts, and the properties of activablc and stable isotopes may be used as the natural tracers. Here, we introduce briefly the results of two field tests with the method of NAA (second way) as follows: a. Shan Tou Harbour. 3 bed-load and 4 suspended load were sampled in the field on March, 18-25, 1985, these samples were tested and analyzed thereafter. We got that the sources of the sediment in the channel of outside bar agree well with the results obtained with the method of heavy mineral ana­ lysis of the same place by You Fang Hu et al.[\] We also got that two sources of suspended-load sed­ iment arc transported from two directions, the river and Niang Jiao (on cast'side) in the deposit of the same channel, and the percentage of suspended-load ir» the deposit is about 37% as calculated. b. North Bank of Hang Zhou Bay. 27 bed-load samples were collected along the north bank of Hang Zhou Bay from the port of Lu Chao on the cast side to Zha Pu on the west side, about 90 km. The concentration of. 30 kinds of elements embeded in each sample was obtained by the method of

128 NAA. Wc compared directly all the field data and applied the theory of fuzzy similarity in the analy­ sis. The result obtained is very interesting, because the locations of erosive and deposited reach which were presented by Chao Pcikui et al.,[2] in the research report of the changes of North Bank about 60 km due to the fluvial processes at the eastern part of Hang Zhou Bay in 1983, arc coincide with our result. Our result gives not only the direction of bed-load movement, but also the relative sediment discharge of 5 local districts and the whole research area. The general tendency of the bed-load movement trends toward to center from both the cast and west side. The percentage of the relative sediment discharge is about 64.5% from the cast side and 35.5% from the west side. The locations of samples collected and the relative sediment discharge of them analyzed arc shown in the figure, so that the result of our study is favourable to the field selection of a new port at Jin Shan. At present, the technique with the method of NAA in the trace of the sediment is comparably advanced among several ones mentioned above in the study of the sediment movement.

Fig. Direction and relative quantity of sediment transport at north bank of Han«ZJiouBay.

There arc several points of advantage of the method NAA (second way) in comparison with the method of artifical tracer as follows: (1) The cost of test can be diminished about 10 times, (2) Field work can be greatly lessened, (3) The time of the sediment sampled almost unlimited, thus one can observe the sediment movement during various periods, such as the season of flood and low water flow or of typhoon, (4) The method NAA with which both the bed-load and the suspended-load can be used specially for the coast of fine sediment dominated with suspended load which is unable to observe with other methods may be widely applied.

[1] You Fanghu, Lin Baorong, A report of investigating sediment silting in the channel of outside bar at Shan Tou Harbour, Institute of Occanology, Acadcmia Sinica. [2] Chao Pcikui, Dong Yongfa, The scouring and silting of some sections in the North Bank of Hang Zhou Bay, Selected papers of East China Normal University, Jan. 1984-Dec. 1985, pp. 360.

129 NEUTRON IRRADIATION OF LiA102 AS CANDIDATE CERAMIC BREEDER

MATERIAL OF THE FUSION REACTORS; V-SPECTROMETRY OF THE AC­

TIVATION NUCLIDES AND EVALUATION OF THE TRITIUM PRODUCED BY

(n,Cu REACTION ON LI-6.

A. MOAURO, P.L. CARCONI

ENEA/TIB/CHIA, CRE Casaccia, P.O.Box 2400, Rome, Italy

In the frame of the european programs for the future fu­ sion reactors, the laboratories of the Chemistry Division of ENEA Casaccia Center (Rome) have been involved in preparing ceramic blanket materials as tritium breeders; a special consideration has been devoted to the preparation of V-LiA102 by syntherization or sol-gel methods (1).

In this paper are reported: a) neutron irradiation of Li- aluminate specimens in TRIGA reactor and /-spectrometry measurements for INAA purposes; b)isothermal annealing of the irradiated samples and tritium extraction, by using an off-line system supplied by CRNL-AECL (Canada).

INAA has allowed the determination of the microimpurities

in the ceramic samples, arising from starting materials

\1203 and Li2C03; also impurities from the powder prepara­

tion processes, have been determined.

130 As regards the tritium measurements, in our system (fig.l) after the breaking of the irradiation quartz vial, the samples are isothermically heated in a furnace and the released tritium is sweeped by He+ 0.1% H2 . gas, so the oxidized form (HTO) is trapped by ethilene glycol in the first set of bubblers. The gas flows then in a drying unit and enters in a on line counting chamber, from which a ionization current, proportional to the amount of HT is ob­ tained. The subsequent CuO bed oxidizes the HT to HTO, that can be measured in the second set of bubblers. These steps are repeated at temperatures ranging from 450 C to 700 C. A screening on different breeder materials will be per­ formed to study the kinetics of the tritium release.

CAPSULE BREAKER

IDNEATIEN CHAMBER DRIER CuQ BCD

FURNACE CLAHP-OH HEATER

DEDXD DRIER UNIT TO EXHAUST - ROTAMETER

NEEDLE < HTTJ BUBBLERS HT BUBBLERS VALVE' ISOLATHWU (J VALVE HI-PURITY Fig.l - Schema of CRNL system REGULATOR SWEEP CAS IN (1) C. Alvani, S. Casadio, L. Lorenzini, G. Brambilla, High Tech Ceramics,Elsevier Sci.Publ.B.V. Amsterdam, 1987, 2941.

131 A. floauv-: and P.L. CfU'C'i'ii.

ENEA/TI& CHIA, ORE Casac-ria, via Angui J.larese 3

An European intercomparisou of vegetal standard reference materials, based on INAA and some tion nuclear spectrocheniical techniques.

Abstract

In the? paper are reported the INAA results obtained on 11 vegetal samples proposed as european reference standard, in nutritional, agricultui"al and analytical studies. A comparison is also reported with the data obtained by 38 european laboratories, by using spectrochemical methods (flame spectrometry, atomic absorp­ tion, ICP etc.) The. utility of INAA method is stressed, particularly for elements not measurable with non nuclear methods, but important as markers of toxic and pollutants sub­ stances. Lanthanides and other rare elements could be used both as fingerprint of the provenance soil, and for evaluating the homogeneity of a sample.

132 \'AA uf IAEA lake Sediment RM SL-J for 45 Elements

\"i Bang-I7 a Ti an Wei-Zhi Chinese Institute ot' Atomic Energy, Beijing

45 el emeu Is have been determined in IAEA Lake Sediment RM 51-3 by NAA. Multi-techniques were used to fully tap Lhe potential of NAA in 1 firms of the number of determinable elements arid the accuracy of cadi datum.

Experimental Highlights of the work are as follows, 1. Routine INAA with two irradiations at our 15 MW Heavy Water Research Reactor and five countings with a 2&'•*', 1.9 keV HPGe was conducted for determinations of most of Ihe 45 elements. 2. Both relative comparison and k,-, standardizations ( for l v indicators ) were used in quantitative determinations, •;. Parameterized Ik,, me I hod. newly developed by the authors, as well as comparative method, was used in the corrections for fission and gamma spectral interferences. 4. An additional irradiation was made at a channel with hard neutron spectrum (u/4>,= 2.5) of our Swimming Pool Reactor ( SPR ) lo facilitate the determination of Ni through "Nidi, p)•' Co reaction. 5. In the delermiriat ion of 2n, the counting system was specifically set up at a MCA conversion slope of 0.35 kcV-'ch to iniprovi; the deconvolution of the doublet 1115 keV (fi,,Zri)-1120 kcV (J?Sr) (ensuring 5 points above fwhm). i-,. Delayed neutron counting, as well as conventional XAA (through.2'?U(n, y |i ~)i-',JNp), was used in U determination. 7, Radiochemical separation was performed in an "effort to determine all the 14 naturally occurring I an Mian ides. A modification of an existing procedure was used.Chemical yields for Pr, Nd, Gd, Tb,Ho, Er and Tm were obtained by interpolation of

133 those for La, f'e, Ziii, Gu, Yb ami Lu which had been accurately determined by INA.A. in this way, the matrix effects in I" ho lit:terminations of chemical yields were totally eliminated. Six subsainples were analyzed to detect the iiihomogenei ty ural evalual.ii the standard deviation for each element determined.

Results and discussion Recommended values for 26 elements have been given by IAEA. Present work is the only one among -J5 participating laboratories (from '£$ countries) submitting data for all these 26 elements with no one outlier. 25 out of the. 2d data are within 95^ confidence intervals of IAEA recommended values, with one exception of Ca which is only 0.36* (rel.) apart from the %'*> confidence limit of IAEA value. Values for another 111 elements we submitted, Ba, Co, Cr, Fe, Mn, Ni. V, W, In and Zr, have also been evaluated by IAEA, and again proved no one sigle outlier for our data. The remaining 6 elements we submitted, Er, Gd, Ho, Mo, Pr and Tin, have not been evaluated by IAEA, due to the few and/or scattered entries. We have also determined other 3 elements, Au, Se and Sn, but not submitted to IAEA because of poor precision resulted from either inhomogeneity or insufficient counting stalistics.

134 STUDY OF THE BIOAVAILABILITY OF ZINC USING ACTIVABLE ISOTOPE TRACER 70ZN BY NEUTRON ACTIVATION ANALYSIS

Bang-Fa Ni, Pingsheng Wang Yingjun Luo, Shouyang Yu Institute of Atomic Energy Dept. of Nutrition & Food Hygiene P. 0. Box 275-50, Beijing of the School of Public Health, P. R. China Medical University, Harbin, China

Zinc (Zn) is an essential nutrient element in the human body. It plays an important role in health, especially for children and adolescents. Low levels of Zn in the human body can cause many kinds of diseases. In recent years, many scientists have had enhanced their interests in studying the bioavailability of Zn in the human body. According to investigations of Zn in children in 18 districts of China, there are about 60% with low levels of Zn (<110 Mg/g in hair). There has not been a method to systematically study the bioavailability of Zn in the diet in China. In the present work, fecal samples from children,., who were given enriched isotopes of Zn in their diet, were collected and low- temperature ashed. A pre-irradiation concentration of Zn was performed using an anion exchanger. The concentrated samples were irradiated and measured for 71™Zn, 69raZn and 65Zn. The content and ratios between 70Zn, 68Zn and MZn were used to calculate Zn availability.

SAMPLE PREPARATION: About 10 rag of the enriched isotopes cf Zn (70Zn 18.3%, F8Zn 50.8% and 64Zn 15.0%) in orange juice were drunk by.children. Collected fecal samples were low-temperature ashed (550°C for 8 hours).

PRE-IRRADIATION CONCENTRATION OF ZINC: About 200-300 mg of the ashed sample was digested in 30 mL concentrated HN03 and 2 mL of concentrated HC10A on a hot plate until the solution gave off small bubbles. The solution was then boiled for 4 hours. Then, the clear solution was transfered to another beaker and evaporated nearly to dryness. Five raL of 9M HC1 were added to dissolve the deposit and transfered into the column of the anion exchanger (9x80 mm). The elution rate was controlled at 1 drop each 8-10 seconds. The beaker was washed with 1 mL 9M: HC1 three times with the washings added to the column. Then, 3 mL 0.5M HC1 were used to wash the anion exchanger. Eight mL of distilled water were added to the column to release Zn and the eluate collected. The eluate was evaporated to dryness on a hot plate. In this procedure, the chemical yield of Zn was found to be 96±2%. Next, 1 mL of concentrated HN03 was added and evaporated to change the medium from Cl" to N03_. Finally, 0.5 mL of 0.1M HN03 was used to transfer the Zn to a polyethylene vial for irradiation.

IRRADIATION AND COUNTING: The sample was irradiated at a thermal flux density of =s2xl013 n cm"2 s"1 for 15 minutes in the horizontal channel of the HWRR reactor by using a pneumatic rabbit system. Standard Mn irradiated simultaniously with the sample was used to monitor flux changes in this work. After cooling for 30 minutes, the sample was

135 measured by use of a HPGe detector with a resolution of 1.87 keV at 1332 keV and a relative efficiency of 28%, linked with a S-40 multichannel analyzer and PDP-11 computer. Figure 1 -shows a spectrum of the sample.

RESULTS AND DISCUSSION: Figure 1 shows that the pre-irradiation concentration of Zn is successful. Zinc in the sample is a mixture of natural Zn with the mass isotopic ratios with respect to total Zn of 0.00662, 0.195 and 0.495 for 70Zn, 68Zn and 6AZn, respectively, and enriched Zn with the mass isotopic ratios of 0.183, 0.508 and 0.150 for 70Zn, 68Zn and 6AZn, respectively. The following simple equations were used to calculate the availability of Zn. Assuming X is the content of natural Zn in the sample and Y is the content of enriched Zn, then three equations can be written: 0.00662X + 0.183Y =• a (1), 0.195X + 0.508Y = b (2), 0.475X + 0.150Y - c (3), where a, b and c are the total masses of the isotopes 70Zn, 68Zn and MZn, respectively, in sample. Solving simultanious equations (1) and (3) or (2), the content, Y, of enriched Zn in the sample can be calculated. The possible contamination by natural Zn in the pre-irradiation concentration procedure need not be concidered. The fractional absorption, F, is briefly described as follows: F = (A0-Y)/A0, where A0 is the mass of enriched Zn given in the diet. In this way, 16 samples have been determined and F is found to be between 15% to 85%. The differences may be due to the amount of dietary Zn and the age of children. .

II .» 1 I- 1 •

Figure 1. A spectrum of Zn in a fecal sample by use of pre-irradiation concentration.

136 ANALYSIS OF FERTILIZER PHOSPHATES USING REACTOR NEUTRONS AND 14 MEV NEUTRONS

R. Niedergesaess, C. Schnier, R. Pepelnik

GKSS-Forschungszentrum Geesthacht GmbH Institut fu Physik, Max-Planck-StraBe D-2054 Geesthacht, Federal Republic of Germany

The methods of instrumental neutron activation analysis (INAA) with reactor neutrons and 14 MeV-neutrons were applied to investigate 32 fertilizer phosphate samples. The samples came from mines in Kola pensinsula (USSR), Florida (USA), Harocco, Western Africa and other sites. Six samples were of primary origin (igneous rocks), 22 of secon­ dary origin (sedimentary) and 3 samples were industrial products.

The dry samples (0.1 - 0.4 g) were irradiated in the neutron flux of the research reactor and of the 14 MeV neutron source facility KORONA at the GKSS Research Center Geesthacht. Up to 45 elements (Na, CI, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Ga, As, Se, Br, Rb, Sr, Zr, Ru, Ag, Cd, Sb, 0, Cs, Ba, up to 11 lanthanides, Hf, Ta, W, Au, Hg, Th, U) could be determined in the phosphates after reactor neutron irradiations of 5 minutes and 3 days (thermal neutron flux ca. 0.9 x 1013 cm-2s"1 and 5 x 10l3cm_2s~1 resp.) Moreover up to 11 major and minor elements (F, Na, Mg, Al, Si, P, Ca, Ti, Mn, Fe, Sr) were determined after irradia­ tions with fast neutrons ( 1.6 x 1010 n cm_2s-1).

The purpose of the investigation was: 1. to test the method of INAA for phosphates in spite of the high con­ tents of phosphorus (7 - 17 %). Besides the continuous underground brerasstrahlung coming from the B-emitter 32P the interferences of the uranium fission products caused difficulties.

2 to check whether the mineral phosphates contain environmental pollu­ tants in harmful quantities such as the elements Cd, Hg, Cr, Ni, Zn and the radioactive element's Th an U.

3. to characterize geochenrically the samples by the different, element patterns or indicator elements and to characterize the'phosphate ; deposits by appyling the statistical cluster analysis.

137 , INVESTIGATION.OF MANTLE-DERIVED MAGMATITES BY NEUTRON ACTIVATION ANALYSIS

A S. Niese, K. Krogner, B. .Gleisberg, CD. Werner , L. Pfeiffer1, W. Kramer2

Central Institute of Nuclear Research Rossendorf, P.O. Box 19, 8051 Dresden, GDR, Mining Academy Freiberg, Brenn- hausgasse 14, 9200 Freiberg, GDR, 2 Central Institute of Physics of the Earth, Telegrafenberg, 1500 Potsdam, GDR.

A number of mantle-derived magmatites of the South of the GDR are investigated by n.a.a. Besides of the elements usually determined by i.n.a.a. in ultramafic rocks Pd, Ir, Pt are extracted with dibenzyldithiooxamid and the r.e.e., 233 239 Pa, and Np are separated using cation exchange after irradiation. The chemical yields of the platinum metals are determined by spectrophotometry. Those of the r.e.e. »•- '88 238 and U with the help of Y and Np as radiotracers. For investigation of the genesis of the rocks the results obtained by wet chemical methods and atomic spectrometry are taken into consideration too. The large number of determined elements enabled us to identify special indica­ tor elements for magmatic fractionations.

In the Saxonian Granulite Massif three units each consis­ ting of layers of lherzolites, garnet serpentinites, koma- tiitic basalts and calcalkaline rocks from dacitic to rhyolitic composition are assumed to be of Lower-Riphaen age. These series are overlaid by an Upper-Riphaen ophio- lite association with serpentinites,, gabbros and diabases. The garnet serpentinites have the composition of slightly modified primary earth mantle material with about two-fold

138 chondritic concentration of nonvolatile lithophile ele­ ments and about 0.01-fold chondritic concentration of Pd, Ir, Pt and Au. The noble metals were added by meteoritic bombardement after formation of the metallic earth core. In lherzolites and serpent'inites large ion lithophile ele­ ments (l.i.l.e.) and Pd are depleted. The mafic, interme­ diate and acidic rocks are derived by succesively partial melting or fractionated crystallization, indicated by small fractionation between light and heavy r.e.e. in connection with growing r.e.e. concentrations. In the mantle-derived melts the platinum and transition metals are depleted in the order Ir Pt Ni Pd Cr Co Fe. The gabbros show lower r.e.e. concentrations than diabases and high Eu/sm-ratios indicate crystallization of plagioclase.

During the Tertiary in the South of the GDR alkaline volcanism with peridodite xenolithes from the upper mantle occure. The alkali basalts derived by about 5% partial melting of mantle material, enriched by metasomatosis with l.i.l.e. From the concentration ratios of Ca-rich and Ca- poor xenolites and from the ratios of pyroxen crystals isolated from phonolites and the phonolites itself an enrichment of Sm, Eu, Tb and Lu in the clinopyroxen was observed. The phonolites associated with alkali basalts are assumed to be their fractionation products. The in­ creasing Yb/Lu ratio in phonolites are the result of the pyroxen crystallization. In comparison with the alkali basalts the phonolites are enriched in Cs K Rb U Th Na Hf La and depleted in Sm Eu Tb Sc. With the help of determined trace elements we identified different steps of melting and crystallization. Contamination by crystal materials can be neglected in the genesis of the in­ vestigated rocks. "

139 • LOW RADIOACTIVITY MEASUREMENT DF ACTIVATED NUCLIDES IN AN UNDERGROUND LABORATORY

S. Niese, W. Helbig Central Institute of Nuclear Research Rossendorf P.O. Box 19, 8051 Dresden, GDR

In radioactivity measurements, the contribution of cosmic rays to be background depends on the equipment used. The type and the energy of radiation must be taken into account too. In order to reduce this contribution we have installed a spectrometer in an underground laboratory covered by 47 m rock and shielded by 0.7 m low radioactive ultramafic rock. An 80 cm Ge(Li) detector was shielded by 0.1 m lead and 0.02 m copper /l/. We have taken advantage of this efficient shielding in low-level gammaspectrjmetry of neutron activated semiconductor silicon /2/, natural radioactivity of rocks for budding materials and of raw materials for cement production, environmental samplesand cosmogenic nucliues /3/.

In order to investigate the background reduction for the measurement of other types of radiation a beta-gamma coinci­ dence equipment of seven plastic scintillators of 29 mm x 0.2 mm in combination with a 4" x 3" Nal(Tl) detector was applied, furthermore a gamrca-gamma coincidence arrange­ ment for positron emitters, a liquid scintillation detector, and a mixture of boric acid with water for neutron counting.

The muon flux density yielding a continuous contribution to the background is reduced by a factor of about 40. In caie of using detectors not manufactured of low radioactive material /4/, it is not possible to obtain this reduction factor in the region of interest of the spectrum.

140 Table 1 Background reduction factors at 47 m underground

Detetors Radiation Gamma Energy, MeV

Ge(Li) Muon 10 40 Ge'li) Gamma i 3.5 Ge(Li) Gamma 2 6 Ge(Li) Gamma 2.5 10 Ge(Li)-NaI(Tl) Positron 0.51 7 NaI(tl)-7 organic Sc. Beta-Gamma 1 r, Ge(Li), boric acid, H^Q Neutron 0.477 15

The main contribution of cosmic radiation to the gamma spec trum below 3 MeV is caused by the energy loss of muons near the edge of the detector due to their short pathways in the detector material. From the background count rate I = K * d~ * r (d = density of detector material and r = radius of the crystal of the cylinder) a value for K can be derived. At sea level: K = 2 E - 5, cps * g * cm" ,

III He.lbig, W. , Niese, S., Birnstein, 0., Isotopenpraxis 20 (1984) 60-64

I'll Niese, S., Helbig, W., 3. Radioanal. Nucl. Chem. Articl 100, (1986) 155 - 163 /3/ Niese, S., Helbig, W. , 3. Radioanal. Nucl. Chem., Lett. 128 (19B8) 245 . /4/ Brodzinzki, L., Reeves, 3.H., Avignon, F.T. Ill, Miley, M.S., 3. "Radioanal. Nucl. Chem., Articles 124 (1988) 513 - 521

141 NEUTRON ACTIVATION' DETERMINATION OF OXYGEN COEFFICIENT FOR HIGH-TEMPERATURE SUPERCONDUCTING MATERIALS

Ni'Kolaenko O.K., Mirotir. I.V. (All-Union Research Institute of Radiation Engineering, Moscow, Varshavskoye Shosse, U6). Golcshteir. K.N., (Inorganic Chemistry Institute, USSR Academy of science, Novosibirsk, Prospekt Akademika Lavrent'eva, 3).

Due to their precision and sensitivity activation analytical procedures are applied in investigating the composition of high- temperature superconducting materials (HTSC) /', 2/. Oxygen content determination is of particular importance as oxygen effects xhe super-conducting properties to a considerable extent. In the report the analytical procedures for ceramic materials on the basis of yttrium and bismuth and their prospects are investigated. In case of analysis of yttrium-based ceramic materials N, Y, -3a are of primary importance while choosing the analytical procedures. In the second case N and Cu radionuclides play a decisive role. To ensure the maximum sensitivity of ;14 MeV neutron activation analysis a scintillation ^-spectrometer has been used to measure induced activity. The major factors affecting the analytical errors are counting statistics, the spectrometer dead time and the instability of the neutron generator flux. Increase in the number of counts along with reduction of the statistical error result in complications regarding the correction for dead time of the measurement line. To correct data for the dead time while measuring simultaneously the activity of several short-lived constituents an approach discussed in paper /3/ has been used. The effect of the neutron flux instability when determining the relation of oxygen content to the content of a matrix element is eliminated by means of a two-constituent sample-monitor. In this case the results are not affected by the uncertainty in time intervals .(that is, irradiation, cooling and measurement times). It results in simplification of the measurement procedures.

C/Y ratio in yttrium-based ceramic material (YBa2Cu,0 ) has been measured during 65 s (30-5-30 s). The effect of copper and barium has been negligible (Fig. 1). Short half-life periods of N and Y ensure to repeat the analytical procedure many times and to achieve high analytical accuracy.

M2 It is expedient to determine oxygen coefficient in yttrium- free HTSC using O/Cu relation. Bismuth-based ceramic material (BiCaSrCupO ) has been investigated in the following mode: T 3C s; t = s| 30 s t = 3 min; irr " cooli 0 meas ? cool2 t =5 min. The total contributio1 n from bismuth, calcium, and meas2 strontium to the region of measurement (0.511 MeV) is O.696.

4r = 30s t Cool-5 5

16w; tmeasz~ 5m t'n

la

energy

Fig. 1. Spectra of YBa2Cu,Ox (I) and BiCuSrCu20x (II) samples. Relative standard deviation for 0/Y and O/Cu ratios is 0.3 to O.596 for 10 parallel determinations.

References

1. Potapchuk V.S., Samosjuk V.N., Tsipenjuk Yu.V. Pis'ma v ZhETF, 1987, t. 43, pril.i s. 184. 2. Zuev A.P.-, Kireyko V.V., Nasonov A.V. Vysokochistye veshchestva, 1988, N 3, s. 133. 3. Ivanov I.N., Nikolaenko O.K. Aktivatsyonnyj anali2 po kor'otko- zhivushchim nuklidam, K., Ehnergoatomizdat, 1987, 120 s.

143 ON THE POSSIBILITY OF EXPERIMENTAL DETERMINATION . OJ? MICROELEMENT BIOVARIABILITY IN BIOLOGICAL SYSTEMS Shonia Nodar, Mosulishvili Liguri, Kharabadze Nana Institute of Physics, Academy of Sciences of the Georgian SSR . P.O.Box 3800?7i Tbilisi, USSR Fluctuations of biological processes in living organi­ sms are inevitable and, to a certain degree, reflected at the level of their elemental composition /1/. This is one of the main reasons determining the variability degree of analytic results with variance D(b). An important factor in the element determination is the methodological error with variance D(m), its magnitude being determined, to a large measure, by the correctness of analytical methods. Hence, the total variance D(t) is: D(t)=D(b)+D(m) The values D(t) and D(m) may be estimated from the ex­ perimental data, while D(b) may be determined by calcula­ tion method. In the present paper we suggest our method of estima­ tion of the mentioned variance parameters. Kidneys of twenty breedless white rats were used as experimental material. Assuming that the physiological function of left and right kidney is equivalent in healthy populations, the following specimens were prepared. 20 samples were prepared from the individual kidney tissues (left kidney) after their lyophilization, in the form of tablets according to the method proposed earlier /2/. All right kidneys were homogenized, lyophilized and tabletized together (20 samples). Kidney samples of both types with standards on the basis of phenol-formaldehyde resin /;?/ were irradiated in the low-temperature channel of the nuc­ lear reactor IRT-M of the Institute of Physics, Academy of Sciences of the Georgian SSR, to the integral flux of ther­ mal neutrons f=10,9n/cm2. The measurements were carried out using Ge(Li) detector with the working volume of 114 cnr 10 days after the termination of the irradiation. The time of each sample and standard measurement T=1000 s. The values of x, ax, D(t), D(m), D(b) (in micrograms per gram of dry weight) and V(b) for some elements, where X=-A-|jXi, ®=toA)mi

i/H A are presented in the table.

144 Values of variance parameters for some elements

Element x(t)±dx(t) x(m)± flx(m) D(t) D(iii) . 1Kb) V(b) individual homogenate %

Fe 510+24 493+12 11831 2915 9025 18.6 Zn 34±1.3 83+1.1 34.8 24 10.9 3.9 z>V 31+1.0 29+0.G 21.2 7.8 13.0 11.6 Kb 18+0.4 18+0.4 3.34 3.5 0.38 3.4 3e 5.0+0.13 4.7±0.12 0.32 • 0.28 0.04 4.2 Go 0.2+0.02 0.13+0.01 0. 0L> 0.001 0.06 40 •

Comparison of D(t), D(a), D(b) values for each of the determined elements makes it possible to estimate, the- qua­ lity of analytical data. The method of determination of a given element content may be considered satisfactory if the condition D(m) ^ D(b)" is satisfied, and excellent if D(m)<£ D(b) Besides, the parameter V(b) allows us to estimate the ho­ mogeneity degree of one or another statistical sampling. Thus, it is evident from V(b) valuer reported in the table that iib, Zn and 3e are uniformly distributed in kidneys, xhile a high variability is characteristic of cobalt. /1/ Emanuel IT.Li. Kinetics of experimental tumour processes •JKauka" (1977) pp.8-9. /2/ Mosulishvili L.Si. et al. Bulletin of the Academy of sciences of the Georgian oort, 101 (1931) pp.133-137- /5/ Licsulishvili L.M0 et al. J. of Kadioanal. and Ihicl. Chem., 85 (1984) pp. 13-19.

145 DEVELOPMENT OF A COMPUTER-BASED SYSTEM FOR FAST NEUTRON CYCLIC ACTIVATION ANALYSIS

S.E. Nonie*, K. Randle** and A.G. Blackband School of Physics Radiation Centre, (** School of Chemistry) . University of Birmingham, PO Box 363, Birmingham, B15 2TT, UK.

Cyclic Neutron Activation Analysis (CNAA) involves the repetitive irradiation and counting of a sample for times far less than that required for saturation, and using the cumulative activity for analysis. The method has been shown to have advantages over the conventional one-shot method, particularly for short-lived activities, for thermal neutron activation analysis [1].

Whilst not limited to single element analysis, CNAA has so far mainly been applied in situations involving the enhancement of sensitivity of a specific element in a set of samples. Application to multielement analysis has not so far been given much attention. This is probably due to the problems involved in dealing with nuclides having very different half lives. In this situation a wider degree of flexibility is imposed on the choice of cycling times i.e. irradiation plus counting and waiting times.

The system described in this work had as its primary goal the development of a technique for the multielemental analysis of geological and environmental samples. Fast neutrons from the ^efd.n)10 B reaction were used for irradiation. The deuterons required for their production were obtained from the 3 MV Dynamitron accelerator at the School of Physics Radiation Centre, University of Birmingham. A microcomputer-based digital electronics interface was developed and constructed to control the penumatic transfer (rabbit) system, carry out flux monitoring by multiscaling counts from a fission chamber, detect sample arrivals and rotation, as well as having the overall control of the irradiation and counting (spectrum accumulation) times. This paper describes the interacting modules involved, and also outlines the circuitry used in the construction of the interface.

The modules constituting the experimental arrangement which interacted through the interface were:

i) a BBC Model B microcomputer, ii) solenoid air valves, which allowed compressed air into the rabbit tube to propel the sample between the beam and detector positions, iii) a 238U fission chamber with associated electronics (preamplifier, amplifier, single channel analyser and scaler) for flux monitoring, including the ability to multiscale these counts [2], iv) rabbit monitors and controls, and v) a fast ADC, coupled to an IBM model PS2 system which served as a •y-ray spectrum analyser.

Aspects of monitoring and control involved in the work were: i) noting the arrivals of the sample at the beam and detector positions and thence activating the start of either flux monitoring or spectrum collection (following a preset decay period if necessary), and ii) monitoring sample rotation during irradiation.

146 A schematic diagram of these modules is shown in Fig.l.

TO COMPRESSOR SCALER

TO MONITORS

SINGLE CHANNEL ANALYSER _, i I MICROSWITCKI T I PNEUMATIC ^^ TRANSFER TUBE AMPLIFIER

TO ELECTRONICS TO IRRADIATION POSITION ' INTERFACE T/O/ RELAY BOX k "UJX MONITOR V, Vj V 8 V^ ARE SOLENOID VALVES 5 MICPOSWITCH I [ ^ TO DETECTOR - POSITION " r^r 1" fc~ 3~~: 4^- COMPRESSOR PNEUMATIC 111 TRANSFER TUBE I i I NEUTRON 3EAM OUT

Figure 1. The irradiation and counting systems and the associated control electronics.

Failure to detect any of these conditions at the appropriate time resulted in the system shutting down and a warning being issued. The electronic system used to monitor these operations is described more fully in the paper.

A test of the reproducibility of the system was carried out through measurements on single element spectra. For a given sample, gamma ray activities were measured between 5 and 30 irradiation-wait-count cycles. The results of these measurements indicated that the system has a high degree of reproducibility - about 95 percent.

By modifying the controlling software, a range of cycling times could be chosen, the lower practical limit being 5 seconds (set by the travel time between beam and detector positions). Software modifications also made possible the incorporation of other devices into the system i.e. those needing pulses or TTL levels to trigger start and stop operations, and one-shot irradiations, with variable Irradiation, could' easily be accomodated by the

[1] Spyrou, N.M., J. Radioanal. Chem., 61(1981)211-242. [2] Croudace I.W. and Randle, K., Chem. Geol., 67,(1988) 165-170

* Permanent Address: Radioisotope Unit, University of Sierra Leone

147 MULTI-ELEMENT DETERMINATIONS OF ROCK SAMPLES USING FAST NEUTRON CYCLIC ACTIVATION ANALYSIS

S.E. Nonie* and K. Randle** School of Physics Radiation Centre (**School of Chemistry) University of Birmingham PO Box 363, Birmingham B15 2TT, UK.

Fast Neutron Cyclic Activation Analysis FNCAA involves the repetitive irradiation of a sample of interest, and counting the cumulative induced activity over a number of cycles. In most of the applications so far reported, irradiation and counting times are set smaller than the half life of the isotope sought. The induced activity grows exponentially with time between one irradation cycle and the next, leading to fairly high activities with attendant improved analytical sensitivities. The method would therefore hold promise in cases involving low neutron fluxes, small reaction cross sections or low isotopic abundancies, or combinations of these factors. It has been shown to be particularly useful in the analysis of short-lived activities, and frequently shows distinct improvement over the conventional, one-shot method in the analysis of these activities. Determinations using half lives ranging from milliseconds to a few minutes have been carried out in this way by previous workers [1-4].

Theoretical considerations and preliminary measurements on the method indicated that saturation activities were attained over cumulative irradiation times far in excess of those required for the conventional one-shot irradiation. The method therefore results in higher specific activities and (used in combination with good detection systems) overall improved analytical sensititives.

Whilst in theory FNCAA is not restricted to the assay of short-lived activities, most previous applications had been limited to short half lives. Furthermore, multielement analyses of composite samples has seldom been attempted. Multielement analysis demands a fair amount of flexibility in the choice of cycling times, with concommitant practical problems. The system that was developed to solve these problems and enable multi-element determinations to be carried out is described in another paper at this conference [5]. In this paper we present the results of multi-element analyses using FNCAA. The fast neutron reactions of interest were inelastic scattering i.e. (n,n'-y) and (n,p). We consider the optimisation of irradiation and counting parameters, data reduction procedures, and finally present the determination of analytical sensitivies for both short-lived and long-lived isotopes in the presence of interfering activities. Half lives studied ranged from 10 seconds to about 20 minutes.

The pneumatic transfer system has already been described [5]. Fast neutrons for irradiation were derived from the ^(d.nJ^He or 9Be(d,n)10B reactions. The deuterons needed for these reactions were produced by the Dynamitron accelerator at the School of Physics Radiation Centre.

148 In addition to the choice of the usual parameters in one-shot measurements, the successful use of CNAA entails a careful choice of the cycling times as well as the number of cycles required to maximise the induced activity, whilst at the same time being within the economic cost limit for the use of the irradiation facilities. Cycling times and number of cycles are closely dependant on the half life of the isotope of interest. Thus preliminary experiments were needed in order to ascertain the proper experimental conditions to be used for the range of isotopes to be determined. In this work measurements on single elements using suitable synthetic standards were used to determine the optimum number of cycles and cycling times. Reactions employed in these preliminary measurements were those of ^Bafn.n'-y) ^"Ba, half life 2.3 min; ^mfn.p) 152Pm, half life 6 min; and ^Alfn.p) ^Mg, half life 9.58 min. The cumulative y-ray activities from each of these reactions were measured as a function of the number of cycles. For the first two reactions, cycling times ranging from fractions of the half-life to a few times the half life were used. For the ^Al(n,p) ^Mg reaction, however, cycling times less than the half life were always used.

The above preliminary measurements were used to determine cycling times that represented a compromise between the short-lived and long-lived isotopes in composite samples. Based on these results and other experimental considerations, a cycling time of 2 minutes was considered appropriate. Using a rock standard as a suitable composite sample, the 7-ray activities following irradiation were measured for some prominent reactions after 5, 10, 15, 20, 25, and 30 cycles. The growth in activity over 5 cycles was plotted as a function of the number of cycles elapsed.

Analytical sensitivities for various elements following irradiation were determined through measurements made on several NBS rock standards over a period of 20 cycles and are presented along with the details of the measurements.

[1] Anders, O.U., Anal. Chem., 32(1960)1368-1369. [2] Anders, O.U., and Briden, D.W., Anal. Chem., 36(1964)287-292. [3] Tani, A., Matsuda, Y., Yuasa, Y. and Kawai, N., Radiochem. Radioanal. Letters, 1(1969)155. [4] Spyrou, N.M. and Kerr, S.A., J. Radioanal. Chem., 48(1979)169-183. [5] Nonie, S.E. and Randle, K. Proc. this conference.

*Permanent address: Radioisotope Unit, University of Sierra Leone

149 THE ELIMINATION OP MATRIX EFFECTS IN THE DETERMINATION OF FLUORINE BY PROTON - INDUCED PROMPT GAMMA SPECTROMETRY C Olivier and H J Morland Department of Chemistry, University of Stellenbosch, Stellenbosch, 7600, Republic of South Africa When prompt gamma—rays, induced by accelerated charged particles, are measured for elemental determinations, the count ratio for sample and standard is given by the average cross-section method as Nx/N0 = cxRx/c0R0 (1) where Nx and N0 are the signal intensities from the sample and standard respectively, Rx and R0 represent the appropiate. ranges and c and c0 the corresponding concentrations. For standards of known composition the stopping powers and ranges can be calculated, but for the sample of unknown composition this is not possible. However by spiking the sample with known amounts of a non—analyte element, which is known to be absent in the sample, and comparing the prompt yield thereof to that of a compound of known composition, also containing the non—analyte element, it is possible to determine the ranges in the sample using equation 1 [l], since the relevant concentrations in the spiked sample and pure spiking compound are known and the range in the pure compound can be calculated as before. Once the range is known the concentration of the analyte element can be determined by measuring the yields obtained from the sample and standards containing the analyte element.

It may be expected, when using total ranges in equation 1, that the accuracy of the results will be dependent on the extent to which the effective range, which applies to the analyte nuclear reaction, correspond to that of the non—analyte element. , The highest degree of correspondence will yield .the highest degree of accuracy. However this condition will only be met in the rarest of cases. In order to overcome this problem it would be ideally convenient if the effective range can be assessed in advance. If it is assumed that the ratio of the total range, R, to that of the effective range,R', is constant for all samples the effective range applicable to the analyte element cap once again be obtained by spiking with a non—analyte element absent in the sample. Taking the above assumption to be correct it can therefore be formulated that R/R' = K. (2) Now substituting the effective range for the pure spike and the relevant yields from the spiked sample and that' obtained from the pure spike itself into equation 1, the effective range for the spiked sample can be obtained, and from equation 2 the total range. Employing the Bragg—Kleeman rule will then yield the total range in the pure sample. Once again taking the ratio of total range and effective range to be constant, the effective range in the pure sample, applicable to the analyte element, can be obtained: This, with the .relevant yields from sample and standards will

150 provide the concentration of the analyte element according to equation l..The range ratios for 5—MeV protons in all elements, with Z varying from 1 to 83, were calculated using the computer program TRIM—89 [2] for hypothetical effective thresholds from 500 keV to 4500 keV in steps of 500keV. In order to obtain a measure of the constancy of the various range ratios, the mean values and standard deviations for each effective range group were calculated and are presented in Table 1 for the two Z—groups 5 to 20 and 1 to 83. Table 1. The mean ratio of the total range to that of the effective range in elements, as a function of the threshold.

Hypothetical Mean Range Ratios, R'/R, for Ep = 5000 keV j thresholds/keV 5 < Z < 20 1 < Z < 83 500 0.923 ± 0.002 (0.22%) 0.966 ± 0.006 (0.62%) 1000 0.926 ± 0.003 (0.32%) 0.914 ± 0.010 1.09%) 1500 0.862 ± 0.004 (0.46%) 0.846 ± 0.014 1.65%) 2000 0.781 ± 0.005 (0.64%) 0.763 ± 0.016 (2.10%) 2500 0.706 ± 0.005 (0.71%) 0.687 ± 0.016 (2.33%) 3000 0.576 ± 0.005 (0.87%) 0.558 ± 0.016 2.87%) 3500 0.503 ± 0.005 (0.99%) 0.486 ± 0.015 3.09%) 4000 . 0.314 ± 0.004 (1.27%) 0.302 ±0.011 3.64%) 4500 0.164 ± 0.002 (1.22%) 0.157 ± 0.006 (3.82%) Judging from the relative standard deviations in the table it is evident that a high degree of constancy is obtaind in all cases since the largest deviation corresponds to a value of I 3.82%. However, if the narrower Z-group is considered, this deviation improves to a mere 1.22% in the extreme case. A useful result which can be exploited since the mean atomic number for the sample is normally known to a close approximation This approach was tested to determine fluorine in the standard reference materials SRM 91, 120c and 694 obtained form the National Bureua of Standards, USA, and was applied to determine fluorine in ivory from elephants in the Etosha National Park, SWA/Namibia. For determining the ranges, compounds containing the non—analyte element lithium, were used for spiking. Here, the yields of the 7 7 429-MeV Li n(l,0) and the 479 MeV Li p(l,0) prompt gamma-rays induced by 5—MeV protons were measured. In the case of fluorine determinations the 110—keV F p(l,0) and the 197-keV F p(2,0) prompt gamma-rays were measured. [1] Olivier, C, Morland, H.J. and Peisach, M., Nucl. Instr. and Meth. B35 (1988) 2263-267. [2] Ziegler, J.F., Biersack, J.P. and Littmark, U., The Stopping and Ranges of Ions in Solids, Pergamon Press 1985.

151 IMPURITY CONTENT DETERMINATION IN HIGH PURITY CSRAUIC POWDERS BY NEUTRON ACTIVATION METHOD

Ana Pantelica , Maria Salagean , Marieta !1 i co I ae *) Institute of Physics and Nuclear Engineering, P.O. B.JIG-6 Bucharest - Romania **) Institute of Research and Production of Semiconductor Materials, Bucharest - Romania

The use of the neutron activation analysis with emphasis to the impurity content determination in some ceramic nonoxidic materials like silicon nitride, boron nitride, aluminium nitride of high purity is presented.

As is well known, the high purity ceramic materials (nitri­ des, carbides) which have penetrated many fields of the ad­ vanced technique (electronics, aeronautics, engineering) are considered as being ones of the most promising material of st the 21 century due to their specific features (high ther­ mal stability, inerty to water and chemical reagents, very high mechanical and thermal endurance).

Already was shown that the physical properties of these ma­ terials and their availability of being used in such many- fields, are strongly dependent of the impurity content.

For such ceramic materials as for instance those used in the semiconductor devices industry, for single crystal ris­ ing , for manufacturing of the adiabatic ceramic engine,etc., the content of some impurities, especially metals, have to be ranging between tens and unities of ppm or even less.

The insolubility of the nonoxidic ceramic powders in chemi-

152 cal reagents, as well as their low impurity content, make the chemical analysis method very difficult for this pur­ pose. Neutron activation method is much more indicated in these cases.

In our experiments the instrumental neutron activation ana­ lysis for determination of metallic impurities in the pow­ ders of silicon nitride, boron nitride and aluminium ni - tride has been used.

The samples and reference materials have been irradiated at 12 2 the VVR-S reactor in a <\, 3 x 10 n./cm . s flux and the mea­ surements have been carried out by using a high resolution GeCLi) detector.

The concentration of 30 elements has been determined. A pe­ culiar attention have been payed to the elements whose pre­ sence above certain concentration is harmful for the speci­ fic properties : Fe, Cr, Ni, Cu, Co, Mg, Mn, Na, K, Zn, Ti, Zr.

For some of the elements determined, the concentration va - lues of ppm order or even ppb order have been obtained.

153 RECENT DEVELOPMENTS IN SHORT-LIVED NUCLIDE ACTIVATION ANALYSIS AND ANALYTICAL EFFICIENCY

Neophytos N. Papadopoulos, Sotiris Synetos National Research Center for Physical Sciences "Demokritos" 153 10 Aghia Paraskevi, Athens, Greece The wide element concentration range in many applications of multielement neutron activation analysis necessitates the flexibility of the analytical system for the optimization of the counting rates and other experimental conditions /1/. On the other hand, the wide half-life range of radionuclides only partly provides the possibility of matrix interference reduction by proper combination of the irradiation, decay and counting periods. Matrix interference is relatively small in case of long-lived nuclides since during their coun-' ting period the interfering short-lived nuclides have more or less disappeared. However, the determination of long- lived nuclides covers only partly the applications of neutron activation analysis. The need for short-lived nuclide ana­ lysis is continuously increasing, not only to enhance the application range, but also because of its higher throughput and automation possibilities. However, in the case of short­ lived nuclide spectrometry high counting rates are usually encountered which might cause pile -up and dead-time problems. These problems can partially be faced by electronic means /2/. However, in case of low element concentrations the to­ tal counts will not be sufficient for good counting statistics since the irradiation and counting times have .to be short for short-lived nuclides. In order to achieve both low counting rates and high total counts, cyclic activation can be applied where the counts are accumu-lated. Cyclic activation has also the advantage that timing and sample position uncertainties during irradiation are reduced /3/. However the presence of long-lived nuclides complicates data processing. In order to reduce this matrix interference, intermediate sample sto­ rage has been applied.

In practice the frequent transfer and stopping of the capsu­ les during cyclic activation causes their damage with the danger of sample leakage and pneumatic tube contamination resulting in background increase. Therefore the air suction system has been modified to ensure smooth capsule stopping at both pneumatic tube terminals. For further background reduction automatic separation of the sample from the capsule has been forseen, even in case of cyclic activation where the problem is the proper reinsertion of the sample into the capsule. These improvements are particularly useful in case of neutron activation delayed neutron counting where only the short­ lived delayed neutrons are measured. The improved analytical

154 system has been applied to highly accurate measurements of nuclear reference materials, for geological samples with low uranium concentrations a.o. Additional applications include the quality control of various materials a.o. Due to the increasing demand of nuclear analytical techniques, efforts focus on the improvement of the analytical efficiency. Thus a flexible automatic pneumatic sample changer has been developed to reduce personnel requirements and operational cost. Computerized data processing facilitates the evalu­ ation of the results. Thus national analytical needs in , various fields as geology, environment, biology, medicine, archaeometry, energy resources, quality control of materials a.o. can be covered more and more by neutron activation ana­ lysis and other nuclear techniques. /1/ Papadopoulcs, N.N., J. Radioanal. and Nucl. Chem., Articles, Vol. 113, No 2 (1987) 351. /2/ Papadopoulos, N.N., J. Trace and Microprobe Techniques, Vol. 6, No 2 (1988) 197. /3/ Papadopoulos, N.N., Synetos S., Isotopenpraxis.24(1988) 7, p. 288.

155 THERMAL NEUTRON ACTIVATION ANALYSIS OF MINERAL NUTRIENTS IN DIFFERENT VARIETIES OF RICE IN INDIA

S. F. Patil, N. S.Ra jurkarCne'e Adhyapak) and K.G.Kanade Department of Chemistry,University of Poona,Pune 411007 India

Rice is a dietary sta pie for more than 60% of the world's population. About 80% of the world rice crop is grown in Asia. Nearly 3000 vari eties differing in morphological and agricultural characters are in cultivation.The present work deals • with the deter mination of mineral nutrients in different var ieties of r ice grown in India by the method of Neutron Acti vation Ana lysis ,which is very much suitable for the est imatiori at tracer levels as in present work, Yamaguchi e t.- al . have applied this technique for determination of trace e lements in pineapple plant.

All th« samples were powder ed a nd then si eved in or der to have the. same particle size, The se were th en encapsul ated in polyt hene capsule and were irr adiated fo r 24 hours along with the standards (A.R.gra de > 99.9% pur e) of eleme nts of inter est in uf fission n eutr on source, _ The activ ity of the r adioisotopes of interes t fo rmed viz. *4Na, *K an d ^Mn after (n,"f ) reaction was meas u red on pre viously cal ibrated multi channel analyzer coup led to HPGe d etector at 1369, 1525, and 847 keV energy r espe ctively. The estimat ion of vario us elements have been don e by compa rator meth od for which the calibration curve s wer e prepare d and are s hown in Fig-1

0 } i t n '" ii a r ,.....,,„.. >^ utm" r / i / :; n«. • s* •

!"<"•••.. '.i->»>„ ,I.I.I n |,fl<.-...

156 The concentration of these elements in different varieties of rice, both in husk as well as in grain obtained from the above calibration curves are presented in Table.1, each value quoted in this Table is an average of three independent measurements.

Table 1: Neutron Activation Analysis of various elements in different varieties of rice

Variety of Concentration of element/ppm rice Na K Mn

grain Husk grain Husk grain Husk

K-184 70*4 54*2 5871*43 4213*66 41*1 47*5 Ratna 141*11 80*3 3202*266 3411*35 32*3 126*10 Masuri 72*2 101*8 2417*44 4583*109 28.7 190 * 8 *0.9 Ind.rayani 52*2 568*39 2239*158 3369*158 33*2 244*6 Basumatee 71*1 80*2 2346*161 3450*103 18.2 46.6 *0.2 *0.6 Ratnagi.ri-1 53.1 127*2 1640*45 2473*57 22*2 180*7 *0.1 Panvel-1 39.1 135*1 2509*110 2780*69 30.7 150*27 *0.7 *0.2

As can be seen from the Table.1 elemental content of husk is found to be higher than that of grain with few exceptions. Further examination of Table reveals that in case of rice grain, K -1C4,Ratna and K-184 shows higher concentrations of Mn, Na and K respectiely while Basumatee, Panvel-1 and Ratnagiri-1 shows the lowest of these elements respectively while in case of. rice husk, Mn and Na show higher concentration in Indrayani and K in Masuri and lowest in Basumatee, K-184 and Ratnagiri-1 respectively.

Thus, Neutron Activation Analysis can be routinely used for elemental analysis of food grains.

1. Hevesy G.and Levi,H., Mat. Phys. Medd.Dan Vid Selsk, 14 (1936) 3. 2. Yamaguchi, S.O., Jadachiha, O.M., Mataso I, Aso. Sueo Tokyo,Nogyo Baigky, Aisotopes, Kenkyustio Kenkyu Hokoku, 3 (1982) 9.

157 NUCLEAR ANALYTICAL STUDY OF ROCK PAINTINGS

Max Peisach; Carlos A. Pineda National Accelerator Centre P.O. Box 72, Faure, 7131 South Africa Leon Jacobson McGregor Museum P.O. Box 316, Kimberley, 8300 South Africa

Rock paintings are abundantly found in southern Africa and are a striking reminder of the life and times of the prehistoric inhabitants of the region. The condition of the paintings varies from bright, fresh examples to those which are actively degrading or are barely visible. Many factors could be responsible for this, e.g. time, the nature of the rock face upon which the art is painted, the microenvironment of the painting and the composition of the paint itself. As a step towards the conservation of the art, analyses were carried out to determine the elemental composition of the paint.

An example of a San painting from the Ha Khotso site in Lesotho was sampled for analysis. The painting was coloured with shades of red with an admixture of white material in varying thicknesses, over a base of Drakensberg Sandstone. This sample was analysed across the painted area in steps cr 1.33mm using a beam collimated to a diameter of 0.5mm. Backscatter analysis with 2 MeV 4He+ ions showed that the main components of the rock matrix were 0, Si, Ca and Fe, while the paint clearly contained organic material, shown by the presence of carbon. Since on most of the analysed spots, the paint thickness was less than the range of the bombarding beam, the observed spectra reflected the combined composition of paint and substrate. However, the measured carbon thickness gave the thickness of the paint layer.

Subsequently the same spots were analysed by PIXE using 4 MeV protons. Since the painted area was insulating, the aluminium foil technique was used to generate an electron flux to prevent charge build-up on the target [1]. Absorbers, of methyl methacrylate were used to prevent scattered protons flooding the detector, and at the same time elminated the low energy X-rays, particularly from silicon.- PIXE analysis confirmed the presence of Ca and Fe in the matrix as well as the normal impurities,

158 Ti, V, Cr, Mn, Cu and Zn often found in iron-rich ores. The relative concentrations of K, Ca, Ti, V, Cr, Mn, Fe, Cu, Zn, Rb, Sr and Zr were used for correspondence analysis [2] of the data. It was found that those spots that were analysed off the painted area and were thus indicative of the rock composition gave representative points that formed an isolated group. Those spots which were covered with thick paint gave another isolated group remote from the first. Samples of intermediate thickness formed a separate group situated between the former two. The substrate group was characterised by a relatively increased concentration of K and Mn, while the paint contained higher values of Ca and Sr. These results indicated that both Ca and Fe were present in both the paint and the rock surface. In order to distinguish between the elemental composition of 't1"""- paint and the rock, use was made of the measured pair. thickness as determined from the backscatter analysis. The results indicated that the red colouration was apparently due to iron-rich mixtures, while the light spots could be due to the addition of calcium carbonate. [1] Pineda, C.A., Peisach, M. , Nucl. Instrum. Methods Phys. Res., B35 (1988) 344-438. [2] Underhill, L.G., Peisach, M. , J. Trace Microprobe Tech., 3 (1985) 41-65.

159 ANALYTICAL STUDY OF NAMIBIAN POTTERY FROM SOUTPANSBERG

Max Peisach; Carlos A. Pineda National Accelerator .Centre P.O. Box 72, Faure, 7131 South Africa

Leon Jacobson McGregor Museum P.O. Box 316, Kimberley 8300, South Africa

Jan H.N. Loubser National Museum P.O. Box 266, Bloemfontein, 9300 South Africa.

Whether trade took place between different communities in the pre-written history period of Namibia, some 500 years ago, still remains an open question. It was hoped that evidence of population movement or trade could be obtained from the study of pottery, the most abundant archaeological artefacts of the area. The region of excavation covered two valleys separated by a mountain in the Soutpansberg area. The geological deposits in the southern valley consisted of granite and amphibolite, while that in the northern valley was sandstone. Pottery excavated from trenches cut in both valleys were submitted for trace metal analysis. By appearance, the pottery from the two regions was indistinguishable. In addition, reference specimens of daga, (a mixture of clay and organic material such as dung) at present used by the inhabitants for potterymaking, were taken from Manavhela and Tavhatshena in the southern valley and Princess Hill and Tshitaka-tsha-Makoleni in the north-eastern valley.

Analyses were carried out at the external beam facility of the Faure Van de Graaff accelerator using 4 MeV protons for PIXE spectrometry. The samples were thick pottery sherds, usually blackened on the outside. Both surfaces of each sample were analysed and in most cases the edge was analysed as well. The elements that were measured were K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Rb, Sr, Y and Zr. Because of possible dilution of the elemental concentrations by carbon, the data were expressed relative to that of Fe

160 in the same sample. The experimental data for 65 samples were submitted for correspondence analysis in order to search for correlation between the trace element concentrations and provenance. The figure below shows a plot of the first two axes. The representative points of the pottery samples separate into two major groups with the southern samples lying in the upper left portion and the nothern samples in the lower right. The reference clay samples follow the sets, also according to their provenance, while replicate analyses were satisfactorily close together, indicating agreement between elemental content and precision. When the values of axis 3 of the calculated correspondence analysis is taken into account, the points for the southern group are seen to lie partly in and partly under the plane of the plotted figure, while those from the north are positioned above the plane. This emphasizes the separation between the two groups. Evaluation of the relative elemental concentrations in each of the two groups showed that the main differences were values about 50% higher for Cr and Ni in the southern group, and 50% higher for K, Ca and Sr in the northern group. Discovery of some samples, which, according to their site of excavation should belong to one group, but were found by analysis to have an elemental concentration profile of the other group indicates that some trade or population movement did occur between the two valleys.

Cr

• • • • • . NI • •

• X X * X • xx X X x Zr Mnx x Sr X X Pottery Clay • . South • o

North x * X Ca \—:— -1 —i 1 1 1 1 i —i ' -8 -6 -U -2 0 2 U 6 8 10 xlO AXIS 1

161 DETERMINATION OF ALUMINIUM AND SILICON IN ZEO­ LITES BY PIXE

Max Peisach; C.A. Pineda National Accelerator Centre P O Box 72, FAURE, 7131 South Africa.

A.E. Pillay; T. Themistocleous Chemistry Department, University of the Witwatersrand JOHANNESBURG, South Africa.

Zeolites are crystalline aluminosilicates which have the ability to pro­ mote a large number of acid-catalysed reactions. The acid activity of zeolites depends on the presence of trivalent ions such as Al3+ in the zeolites framework of shared Si04 tetrahedra. Without their presence, crystalline silicas have no acid activity. It was shown that their acidity increases with increasing Si/Al ratio until it reaches a maximum and then declines again. The rate of deactivation of zeolite catalysts was dependent on the Si/Al ratio. This ratio also affects some of their physical properties such as thermal and hydro thermal stability and some of their chemical properties such as hydrophobic- ity and stability towards acid solutions. It is therefore clear that the determination of Si/Al ratio of zeolite catalysts is of extreme importance.

Although neutron activation analysis is a widely-used method for ele­ mental analysis, this method is open to error when adjacent elements are analysed. Since the same nuclear reaction product is formed by the (n,7) reaction on element Z, by the (n,p) reactions on element

162 (Z+l) and by the (n,o;) reactions on element (Z+2), the presence of element (Z+l) and/or (Z+2) could interfere with the determination of element Z. In the case of zeolites, where Al and Si are to be deter­ mined, through the measurement of the activities of 28A1 and 31Si, serious interference may be encountered if P and S are also present 31 28 31 31 34 31 in the sample, from P(n,or) Al, S(n,p) Si and S(n,7) Si. For routine analysis, therefore, an alternative method was preferred. The prompt emission of X-rays under proton bombardment has already been shown to be suited to the routine determination of Si/Al ratios

The present investigation compares the methods of X-ray fluores­ cence (XRF) with that of Particle-Induced X-ray Emission (PIXE). Using 1.0 MeV protons on thick targets of zeolite pellets, aluminium and silicon were determined by PIXE. Results were compared with XRF data. The relative root mean square error was 3.7% and the results of the two methods agreed with a correlation factor of 0.991. PIXE analysis can be carried out on very small samples, while sample preparation involves minimal handling.

[1] A.E. Pillay, M. Peisach, R. Carolissen and C.A. Pineda, Nucl. Instrum. Methods B4£ (1990) 333.

163 . INAA OF IAEA RM IAEA-155 WIEY POWDER FOR PHOSPHORUS AND OTHFR i\ ELEMENTS

Peng Lixin , Tian Weizhi Institute of Atomir Energy P.O.Box 275 (50) ,Be.ijing. China

Recently there has been an increasing intewst in evaluating the role or effect: of trace elements in the biosphere. There fore accurate determination of I lie concentrations of the trace elements in foods, animal tissues ami other biological materials are very import ant, so the need fur suitable reference materials is particularly ac-ate for quality assurance in this field. IAEA has recently organized an intercomparison study on a new biological RM IAEA-155 Whey Powder.

Tiie potential of accuracy ,multielemental capability, high sensitivity and freedom from con lamination problems.and matrix effects of INAA make it an extremely valuable tool for use in SP.M certification .

In present work, P, as we.11 as other 21 elements has been determined in IAEA RM IAEA-155 Whey Powder by INAA ..

The determinations of phsphorus in biological samples were carried out with NAA through "PC n, gamma )"P reaction followed by radiochemical separation and counting for beta activity produced by "P during the early 60's. Latter, Sabliiojii el. at [1] suggested measurement of Cerenkov rndi ation after 30 m irradiation and one week decay .Ehniann et.al [2] have proposed a dcriv ative neutron activation analysis (DNAA) in which P is determined by measurement of a gamma emitter BV . But Ihe chemical separation work is quite tedious, time-consuming and destructive . Today attention has been for.usspd to INAA mc-lhod . In a recent study , Bajo and Wytenbach [ 3] have sugge-jled measurement of hremsstrahlung from "P by using a well-type NaUTl) detector . However , it ir; our feeling that a more comprehensive analysis on the spectral interferences is needed to obtain accurate results . Interferences involved in P determination by means of INAA based on tie gamma-spectroscopy can be divided into two categories—those from reactor neutron induced threshold reactions ( mainly sS(n,p>, and rT!(n, alpha)) and those from the Ge gamma-spectra ( the integral in the energy region of 100-150 kev (used for T measurement)

164 ••on lr Hinted by beta br Pins trail lung from nuclides other than '*'P and Comptou distributions from all the high energy gntima-rays) . In present work , all inlf.TferPtit.es have been corrected for . P ooucenlralions in IAEA I"• rr and some NBS SRMs liave been delermined by this method ,ami shown excel lent agreement with certified or consensus values. The results show that Ge gamma-spec Ironic try is a sensitive and specific method for INAA of phosphorus ., which has a pure beta nuclide cBP) as a reaclor NAA indicator .

In the determinations of some other long-lived elements, an absorber made of plastic, Al and Cd was used to reduce low energy breinsstralilung produced by beta rays from "P. The measurement of Al through the reaction 9Al( n, gamma) "AI suffered an interference from the fast neutron reaction "P(n, alpli,i)"Al . This was corrected from the P content of this material, and an. interference factor of 3.4"10"' based on the calculation [\] .The results obtained from this study are in good agreement with the evaluation of IAEA

[1] E. Sabbioni, L, Cleric.], F. Girardi, !<'. Campagnari. J. Radio anal. • ' Chen.,14(1977)159-169. [2], \t D. Ehmann, R. C Young, D. Vi. Koppenail, VS. C. Jones, M. N .Prasad, J.Radioanal.Nucl.Chem., 112(1987)71-87 . [3J 5.Bajo,A.Wytteiiliadi,Talantn, 35(1983)717-751 . [4] Vleizhi Tian, Shuxin Zhang,J.Nucl.Radiochem., 11(1989)84-90 ,(in Chinese)

165 A SENSITIVE BORON PROBE USING THE REACTION 10B(3He, n)12 N

E.A. Pillay Department of Chemistry University of the Witwatersrand P.O. WITS 2050 South Africa

Max Peisach National Accelerator Centre P.O. Box 72 FAURE 7131 South Africa

The potential use of the exoergic reaction l0B(3He,n)12N for the determination and profiling of boron was investigated. The need for accurate boron analysis exists in many fields. Thus, for example, the presence of boron in metals can affect their behaviour, and in superconductors, accurate analysis can resolve problems of stoichiometry. Depth profiling of boron in silicon and semiconductor materials is often essential. The commonly-used techniques are often not suitable for boron determination. .PIXE cannot be used because the energy of the boron X-rays is too low. Thermal reactor neutron activation yields a very short-lived neutron capture product, while the high cross section (n,ct) reaction results in a stable product. Prompt charged particle spectrometry of the emitted alpha-particle is difficult to effect in the large flux of neutrons prevailing at the irradiation site. Proton activation produces long-lived beryllium-7 which has a half-life of 53.4 days and as a result, the activated sample has to be stored for a long time until the radioactivity has decayed to an acceptable level. Prompt gamma-ray measurements from proton and alpha-particle irradiation have proved useful for the determination of boron as a minor component in a variety of matrices, but the sensitivity was insufficient for trace levels. By contrast, activation with helium-3 has many advantages. The exoergic nature of the • reaction allows for the use of a wide range of bombarding energies.: The low Z-value of boron ensures a low coulomb-barrier for the reaction. [This feature is particularly attractive for the use of small accelerators.] The high energy beta' decay of nitrogen-12 • allows for interference-free measurement, when silicon is absent. In the presence of silicon,

166 the reaction 28Si(3He,t)28P yields a product with a high energy beta decay, but the energy threshold for this endoergic reaction is about 15.3 MeV. Hence this potential source of interference is eliminated for helium-3 energies below this value. Energetic 4.43 9-MeV gamma-rays are emitted from the decay of nitrogen-12. Under continuous irradiation, this gamma-ray can be measured as a unique indication of boron, while gross neutron yield measurements can simultaneously be carried out to yield replicate analysis from a single sample. The short half-life of nitrogen-12 (11.0 ms) ensures that the product sample does not retain radioactivity after analysis. With pulsed helium-3 beams, pseudo-cyclic activation analysis is used for determining boron through measurement of its decay products. Analysis is continued until the required precision is attained.

167 PROMPT ANALYSIS OF RARE EARTHS BY HIGH ENERGY-INDUCED (p,X) REACTIONS

Carlos A. Pineda; Max Peisach National Accelerator Centre P.O. Box 72, Faure, 7131 South Africa

As a result of the discovery of rare earth based high-Tc superconductors, there has been a growing interest in the availability of sources of rare earths, their separation and sensitive techniques for their analysis. The measurement of rare earth concentration by Proton- induced X-ray Emission (PIXE) using protons of a few MeV depends on the observation of the L X-rays. Since these X-rays have overlapping energies, it is difficult to determine individual rare earths in typical sample mixtures [1]. Furthermore, the yields of K X-rays using low energy protons are too small for sensitive analysis [2]. On the other hand the energies of these K X-rays are sufficiently different to be separately resolved by intrinsic-Ge detectors. The use of K X-ray analysis using proton beams of 30-66 MeV for the determination of traces of rare earths is suitable because of the relatively high cross-sections [3], as well as the improved sensitivity of analysis [4].

Calculations of PWBA cross-sections show that the maximum values occur at proton energies between 74 MeV (for La) and 125 MeV (for Lu). However, for all the rare earths the rate of change of cross-section with energy is relatively low, so that near-maximum yields can be obtained at bombarding energies less than the maxima. Measurements were carried out with 40, 66 and 126 MeV protons at the Faure 200-MeV separated-sector cyclotron. Cross-sections and detection limits were obtained from the bombardment of thin targets of the fluorides of the rare earths, using a planar 5mm-thick intrinsic germanium X-ray detector. The background radiation was surprisingly low when thin films were bombarded. Thus, for example, the nett peak-to-background ratio for GdF3 was 9.6, while for the very heavy rare earth Yb the value was still above 4.0. From the observed spectra the calculated detection limits were of the order of 20 ng/g for a lmC bombardment with 66 MeV protons. However, with increasing bombarding energy and current, resolution problems were experienced. As a result of nuclear interactions between the energetic

168 bombarding protons and target nuclei, satellite X-rays (both Ka and Kg) were observed from the (Z+l) element for irradiation of the rare earth, element Z. The intensity of the satellites were measured relative to the intensity of the corresponding X-rays from the target element, and were found to range from about 2.2% for Gd in Eu targets to about 7.6% for Tm in Er targets. These values referred to the combined Kai , and Ka2 X-ray yields, as shown in the upper-curve of the figure. The lower curve refers to the satellite X-ray yield of the Ka. only. Since rare earths are usually present in mixtures in materials under analysis, the yield of satellite X-rays are important for the correct stripping of observed X-ray spectra.

T SP1TELLITE EFFECT CONTRIBUTION Ep = 66 rteV

LU

58 64 66 70 RTOMIC NUMBER

[1] Hirokawa, T., Nisihiyama, F. , Kiso, Y., Nucl. Instrum. Methods Phys. Res. B31 (1988) 525-534. [2] Peisach, M., Lackay, L.G. Gihwala, D., Analyst 114 (1989) 279-286. [3] Ramsay, W.D., Al-Ghazi, M.S.A .L. Birchall, J., McKee, J.S.C., Phys. Letters 69A (1978) 258-260 [4] Durocher, J.J.G Halden, N.M., Hawthorne, F.C.. McKee, J.S.C. Nucl. Instrum. Methods Phys Res B30 (1988) 470-473

169 INAA AMD PIXE STUDY ON TKli COMPLEX MODIFICATIONS OF HUMAN BLOOD SERUM MINERAL COMPOSITION IN SEVERAL HEMOPATHIES

E.A.Preoteasa1, M.Salagean1, A.Pantelica1, St.Derceanu2, D.Plostinaru1, 3.Constantinescu1, V. Lungu1, Al.Vilcu2 1) Institute of Physics and Nuclear Engineering, Bucharest- Magurele, P.O.Box MG-6, Romania; 2) Fundeni Clinical Hospital Hematology Clinic, Bucharest, Romania

The potential of INAA and PIXE methods for the detection of microelement variations in pathological human blood serum has been evaluated. A comparative survey on five single ca­ ses of different hemopathies and on normal adults has been made. Four cases were hereditary hemolytic anemias by hemo - globin defficiencies (thalassemias, spread in the Mediterra­ nean area and in the South Asia, and sickle cell disease, incident in Africans and Afro-Americans); the fifth was a ma­ lign lymphogranulomatosis. The patients were ailing of 3-he- terozygous thalassemia ( T); 3-homozygous thalassemia ( lT);

B-homozygous thalassemia with neurological symptoms (nT); heterozygous sickle cell disease in crisis (j^S); and Hodgkin disease (JL). The control sample was pooled from four healthy blood donors. For INAA, the liophylized sera and reference materials have been irradiated in a 3. 10l2n/cm2, s in a VVR-S reactor and for PIXE method the samples were irradiated in a U-12o cyclotron with 4.7 MeV a particles. The concentration of 23 elements (Na, Al, CI, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Cu, Zn, As, Se, Br, Rb, Ag, Sb, Cs, Ba, Au,IIg) has been determined. A comparison with the normal concentra­ tion in literature [1,2] has been made. Each case presented a specific matrix of pathological concen­ tration variations in serum. Major variations ranged between 1-2 elements for the H case and 8-10 elements for the J^S case. The alterations were more extensive in any of the hemolytic anemias than in the Hodgkin disease case. The £s case strik­ ingly showed concentrations with orders of magnitude higher than normal for Ag, Au and Hg; unusually higher for Cr and ma­ jor increases in K, Fe, Cu and Br. It is worth noting the si - multaneous increase of K, Cu and Fe in this case. The content in these elements decreases in malaria [3] so their high le - vels could be associated with antimalaric resistance in si - ckle cell anemia subjects. Fe was increased in all four hemo­ lytic anemias cases, due to hemolysis, with a maximum in ^T. H h H In all three thalassemia cases' ( T, T, nT), Mn increased, Cr decreased, and Al showed disperse abnormal levelsjprobably

170 Cr3+ and Al3+ ions substitute Fe3+ in the defficient hemo - IT globin synthesis. A decrease in Rb appeared both in the T and *[T cases. In the T and ^T cases the decrease of Br and the appearance of Ti traces were observed. Cu was higher than normal in the hemolytic anemias cases,with the only exception of the HT case; if free in serum, Cush­ ions induce red blood cell lysis and lipid peroxidation [41. Possibly, the lack of increased Cu in the ^T case was associ­ ated (a) with the considerable hallotypic variability of tha­ lassemias [5] , or (b) the contribution of Cu to the patho - logy was "substituted" by the higher levels of other metals (Mn, Ag, Ba-unusually high, Hg), and, perhaps, of a semimetal (Sb, unusually high) with the same valencies and/or electro - negativity as copper. The highest by far Cu level was found in the KT case. It was associated with abnormal erythrocyte membrane fluidity and intense hemolysis . It could also ac - count for the neurological symptoms in §T, as it does in Wil­ son disease. In the Hodgkin case, the decreased level of Se- a potent bio­ logical antioxidant [6] - might be related to the intense peroxidations in malignity. Considering the H case (low Se) together with the |[T case (normal Se) and the &S case (high Se), one observes that the polyunsaturated fatty acids in the sera in excess to the normal, parallels the Se level.

Thus, in a study on different heraopathies single cases,INAA and PIXE proved powerful methods for detecting mineral varia­ tions in serum. As these were associated with trace elements unseen in current clinical investigations, our multielemental analysis showed remarcable diagnostic possibilities. Moreover, certain abnormal concentrations correlated with other proper­ ties of blood. For all the complexity of the results, our scrutiny on the role of some few of the microelemental varia­ tions shed, light on the potential of this analytical ap­ proach in blood pathology. [1] Documenta Geigy, Wissenschaftliche Tabellen, Basel,1968. [2] J.Versleck et al., Clin. Chem. 23, 1301, 1977. [3] K.B.Barnes et al., Advan. X-ray Anal. 18, 343, 1975. [4] S.Ribarov et al.. Experientia 38, 1354, 1982. [5] L.Onsorio-Almeida et al., 18th FEBS Meet.,Ljubljana, 1987. [6] Z.Luoping et al., J.Mol.Sci. (Wuhan, China) 3, 235, 1985. One of us (E.A.P.) thanks Drs.. O.Horer and V.Grecu for useful discussions and Drs. V.Apateanu and G.Mateescu (Bucharest for support.

171- MUITI-ELEMENT DETERMINATION OP SOIL SOLUTION BY NAA

Qian Qinfang, Wu Suiqin, Tan Jibing Institute of High Energy Physics,Academia Sinica,P.O.Box 2732,Beijing,China Chen Sluqing Institute of Geography,Academia Sinica,Beijing,China

Study of chemical constituents,especially trace and ultra- trace elemental concen­ trations, in soil solution in the case of the same concentrations of N,P,and K will provide scientific information for building a suitable soil environment for plant growth, and reasonable application of manure and fertilizer.

Thirteen soil samples were collected from the wheat fields of Beijing Agroecosystem Experimental Station at different sites and different growth stages of plant and dried at room temperature.Then,each sample was prassed to get soil solution by squeezer under the pressure of lOOKg/cm .

The soil solutions,each 10-20ml portion,were preconcentrated by evaporation at low temperature 60-70 C in a dustproof hood. The residues" were trasferred to a clean polyethylene film, dried and then analyzed by INAA.

The following conclusions can be drawn from our analytical results: l.The chemical compositions in the soil solutions are very complex. They not only contain the essential elements for plant growth, e.g. Ca, Zn, Se, Fe, Mo, Co, etc, and harmful element As, but also ultratrace elements of Au, Sc,rare earth,etc. The concentrations of Yb,Eu,Ta,Th,Tb,Sc,Cs,Hf,Lu and Au in soil solutions below O.lug/L; La and Sm are.0.1- lug/L; Sb, U, Ce, Se, Cr, Mo, As, Co and Rb are 1.0-10ug/L; Br, Fe,and Zn are lOug/L-lmg/L; Sr is 0.1-7mg/L; Na and Ca are 10-600mg/L.

2.The concentration changes of Cr,Co,Mo,Sr,Zn and Ca in soil solutions at different growth periods of wheat are clear.For example,the content of Mo is 5.13ug/L in the seeding stage, 1.59ug/Lin the heading stage and blooming stage,and 7.06ug/L in the mature stage.

172 S.Elemental concentrations in the soil solutions vary with different depths of soil sections in a range of 1 metre.Tlie concentrations of Sm,Sb,U,Ce,Sr,Mo,Au,La,Ca,Na are higher in the surface layer than in the subsurface layers.But Fe and Rb exhibit the contrary tendeiicy.The concentrations of Th,Sc,Ta and rare earth do not show any significant changes in both layers.

4.The wheat growth has close relation to the concentration of Ca in soil solu- tions.The soil solutions from cultivated soil where the wheat growed well(refer to the height of the wheat and the color of leaves)have higher calcium concentration in comparison with those where the wheat growed poor .From the physiology of plant growth,it is known that plant growth is connected with concentration of Ca in solution within a certain concentration range.lt will probably be a path to increase agricultural products.

At different time during a day, the concentrations of Ca in soil solutions are dif- ferent.lt is higher at noon than in the morning and at night.

173 A NEUTRON ACTIVATION ANALYSIS STUDY OF THE BACK­ GROUND VALUES AND STATES OF ELEMENTS IN NATURAL WATER

Qian Xingzhen, Li Xiuxia Institute of Hing Energy Physics, Academia Sinica P.O.Box 2732, Beijing, China

The present work determines the natural background values of 25 elements, and the states of 20 elements in river, swamp, lake and rain water from, the Nenjiang River by neutron activation analysis method. The Nenjiang River is located in the north of China. It is important surface water resource for Heilongjiang Province.

In our study the water samples were natural and clean, without any contamination. A portion of the sample was passed through a 0.45 ju millipore filter to remove the suspended particles and the other portion was not filtered. 100 ml of each was preconcentrated by freeze-drying and low- temperature evaporation, respectively. Mixed standard and standard reference material SRM 1632a were used. The dried water sample and the standard were irradiated simultaneously in the heavy-water cooled nuclear reactor for 20 h with thermal neutron flux = 6 10 n/cm s. after simple chemical treatment (to remove Na with HAP), the radioactivity of the sample was measured by a spectrometer. The GeLi detector has 136 cm effective volume.

The contents of As, Zn, Cr, Fe, Co, Ca, Sr, Ba, Rb, Cs, Th, U, Mo, Sb, Se, La, Ce, Nd, Sm, Eu, Tb. Yb, Lu, Hf and Sc in the river water were determined bv neutron activation analysis. Their averages are all within the range of the average contents of world freshwater. This indicates that the water resources are unpolluted. Thus, the contens of elements may be taken as the natural background values of elements in the river water of the Nenjiang Rivers system. The variation coefficients of elemental concentration are all within 50 %. Therefore, the contents of elements in the river water of the Nenjiang River are constant.

The contents of elements in swamp water, lake water and rain water were also determined. The contents of iron family elements, including Fe, Co and Cr, in swamp water are the highest, being 6-9 times as large as those in other water samples, while in lake water they are the lowest. The contents of alkaline earth family elements, including Ca. Sr and Ba, arc very close to the corresponding contents in swamp water, lake water and rain water, while those in river water arc

174 about ten times as large. The contents of rare earth elements, including La, Ce, Sm, Lu. Yb, Th and Sc. in swamp water are the highest, too, being 2-4 times as large as those in other water samples. The contents increase in the following order for different water samples: in swamp water > in river water > in lake water and rain water. The contents of other rare elements, including Rb, Cs and As, are very close to the corresponding contents in all the water samples.

The percentage of the contents of both soluble and suspended states of 20 ele­ ments contained in river water, swamp water and lake water, respectively, were determined by neutron activation analysis. Co, Ca, Sr, Ba, Rb, U, Mo. Sb and As are mainly in soluble states, as cations or anions. Tin:* contents of Cs and Cr in soluble and suspended states are. close. Fe, La, Ce, Sm, Nd, Eu. Ln, Th and Sc are mainly in the suspended states.

175 ELEMENTAL ANALYSIS OF AGRICULTURAL SOILS IN MAHARASHTRA (INDIA) BY INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS.

N.S.Rajurkar (nee Adhyapak), S.F.Patil and P.R. Ballari Department of Chemistry, University of Poona, Pune 411007 India

Soil along with the atmosphere constitutes the natural medium which supports the growth of plants on earth's surface. Soil is perhaps the more important of the two as plants derive their most essential nourishment from it.

The laboratory testing of soil is generally supplementary to field examination which provides a basis for classification of soil and determine the plant's nutrients contents in soil, so that deficiencies, if any, may be made good by suitable manurial treatments.However, usually such test are very elaborate, time consuming and hence less precise.The present work demonstrates a simple, sensitive and specific technique viz. instrumental neutron activation analysis (INAA) . for the elemental analysis of soil.Nilubol and Kafkafx have used this technique for the determination of Mn content of soils and the plants grown on these soils.

The soil samples from the different regions of Maharashtra were collected. These samples were powdered, sieved, to 225mesh size,packed into the air tight polythene capsules, and then subjected to irradiation in a - Cf spontaneous fission neutron source. The time of irr£.c'iation was chosen depending on the half-life of the isotope formed. All the A.R. grade powders (99.9% pure) were used as standards, he activity of the radioisotopes viz. Al, Mn, Na and I K formed resulting from (n,*- ) reaction w?.s measured at 1779, 847, 1369 and 1525 keV energy respectively on previously calibrated multichannel analyzer coupled to HPGe detector.The calibration curves for these elements are shown in Figs 1 (Al, Mn) and 2 (Na, K ).

The concentrations of various elements in different soil samples were then estimated by comparator method using these calibration curves and are tabulated as shown in Table.1. An examination of table 1 reveals that in different soils, concentration of various elements is in the order Mn < Na < K < Al . With the exception of soils from Javalwadi and Korhale. It can also be seen that concentrations of Al, Mn, Na and K is found to be highest in the soil from Jorvi, Javalwadi, Takali-Takeshwar and Kolhar and lowest in Korhale, Kolhar, Jorvi and Javalwadi respectively.

Thus,the method INAA can be routinely used for elemental analysis with good precision.

176 F«l-C£loroint «r«. Im Nwlro. Act*«t(M

TABLE 1 : Concentration of various elements in different soils in Ahmednagar district of Maharashtra State (India)

Sr. Description Concentration of the element 7 ppm No. of the soils ~ A1/10J Mn Na K

1 Jorvi 55.,3*0. 7 896*15 3066*32 4213*127 Ta.Sangamner 2 Javalwadi 52.,3*0. 3 1450*10 3083*50 3326*109 Ta.Pathardi 3 Takali-Takeshwar 48.,4*0. 4 1233*6 7810*10 4833*60 Ta.Parner 4 Nevasa 49.,4*0. 2 743*11 4010*36 6163*41 Ta.Nevasa 5 Mandavgan 50.,01*0. 3 1006*11 3560*10 5790*30 Ta.Shrigonda 6 Korhale 45..2*0. 2 992*12 5453*35 5000*80 Ta.Kopargaon 7 Kolhar 50.,1*0. 9 627*5 4923*23 9916*65 Ta.Shrirampur

References :

1. Hevesy,G. and Levi, H., Mat.Phys. Medd. Dan Vid,'. selsk 14 (1936) 3. 2. Nilubol. A. and Kafkafi,U., Proc. symp. on Isotops and Radiation in soil-plant nutrition studies (1965) 63.

177 EVALUATION OF HOMOGENEITY OF SELECTED REFERENCE MATERIALS

FOR SELENIUM BY CYCLIC NEUTRON ACTIVATION ANALYSIS

R.R. Rao, L.S. McDowell, C.K. Jayawickreme and A. Chatt*

Trace Analysis Research Centre, Department of Chemistry Dalhousie University, Halifax, Nova Scotia, B3H 4J1 Canada

Reference materials (RM) and certified reference materials (CRM) for trace elements are used for not only evaluating the reliability of a new analytical method but also ensuring the quality of data obtained in routine analysis schemes, it is a well-accepted practice today to include an appropriate CRM or RM in every batch of samples analyzed to test the accuracy of data obtained. These materials are also being increasingly used for various reasons by some researchers as multielement comparator standards for calculating elemental concentrations of their samples.

Two of the most desirable properties of a reference material are high accuracy of the certified values and its high degree of homogeneity. Environmental and biological reference materials of natural origin, being inherently inhomogeneous, are certified for multielement concentrations for sample sizes generally in the range of 100-250 mg. Some of the modern analytical techniques are capable of analyzing very small sample sizes, viz. less than 10 mg, and require reference materials of similar masses. In another situation, only a small amount of sample is available for analysis which must be done with a high degree of accuracy. In order to justify the usage of a CRM or RM of a mass lower than that recommended by the issuing agency, it is necessary to evaluate their homogeneity at lower mass ranges. The homogeneity of a reference material is generally evaluated by analyzing replicate samples for a few selected major and minor elements. However, homogeneity with respect to these elements does not guarantee the same for trace and ultratrace elements. The degree of homogeneity of several biological and environmental CRM and RM for a number of trace elements is being investigated and their sampling constants calculated in our laboratory.

This paper deals with the evaluation of homogeneity and calculation of sampling constants for selenium in four biological CRM and RM, namely Chinese Hair (HH- CH-1), Animal Muscle (IAEA H-4), Animal Blood (IAEA A-13) and Wheat Flour (NBS SRM-1567). Upto five mass ranges {viz. 5-10, 45-55, 90-110, 235-265 and 330-370 mg) from a single bottle of the given reference material were selected

178 for the preparation of subsamples. Six replicates at each mass range were weighed into precleaned 1.2-mL polyethylene vials. Six replicate selenium comparator standards, of identical geometry and similar selenium content as the reference materials, were prepared by directly pipetting a known aliquot of ultrapure selenium atomic absorption standard solution (SPEX Chemicals) onto a sucrose matrix (Koch-Light Laboratories) in precleaned 1.2-mL polyethylene vials.

Selenium concentrations were measured by a cyclic instrumental neutron activation analysis (CINAA) method developed earlier in this laboratory. The method consisted of an irradiation time of 20-60 s, a decay time of 5 s and a counting time of 20-60 s. The number of cycles (n) at each mass range was optimized to give a desired counting statistics. All irradiations were done in the Dalhousie University SLOWPOKE-2 Reactor at a highly stable, reproducible and homogeneous flux of either 1 x 1012 or 5 x 1011 n cm s"1 using the fast transfer cyclic system. The 162-keV gamma-ray of the 77mSe nuclide with a half-life of 17.4 s was used for assaying selenium.

The results obtained are given in the following format: name of CRM or RM (pooled average selenium content in ppb, certified or reported value in ppb): Chinese Hair (633±65, 72Q±90), Animal Muscle (299.+30, 280_±34), Animal Blood (233_±39, 24Q±80), and Wheat Flour (1015±85, 1100_+200). The homogeneity of the reference materials was evaluated using the F-test, and the sampling constants calculated by Ingamell's method. The details of the experimental method, errors ivolved, statistical analysis of the data, and theory of sampling will be presented together with the results.

179 A Sophisticated Irradiation Facility for the Strongest Am-Be Neutron Source of the World. Samad Rastikerdar Physics Department, Isfahan University,P.O.Box 166,Isfahan,Iran. A nzio AijAtew XM dzblgwzd and conAt/mctzd faon tiiz 50-cmuz amcAA.cMm-241 / bzAylLlum nza.tn.on AOUACZ ofi thz Ph.yi4.c6 Vzpafitmznt o& li&alian Uiiivzuity. Tliz 6oan.cz ukXh thz nzu-Pion zmiA&ion latz o& appfwxAinatcZy 2.K10& nzuXAon pzn. Azcond u> thz AtnongzAt oft it& own [ztnd -ui tliz wonZd. Although thz 6ij6tm li> mal\ity duignzd ^on. nzutAon activation ana£ijAl6,but at thz 6amz timz it can bz u&zd ^on othzh. appticatiom Audi a& nzatxon fiadA.ogha.phy.

1.Introduction

It is very clear that not all the university or research institut­ ions particularly in developing countries can afford to have a nuclear reactor or an accelerator for the purpose of neutron activation anahysis, although many of them for a variety of reasons have serious interests in using and also developing the technique. What other alternative does exist for them? They are faced with two problems. The first one is the budget limitation and the second one is the restriction of export of some isotopes like plutunium-239 to certain countries. Therefore their choice is restricted to certain (o(,n) or (tf ,n)sources. Californium-252 is of course another choice,but considering the half life of 2.6*1 years, economically it is not feasible. Talcing all the above facts into account, Am-Be source with the half-life of ^32.02 year for americiuifr^l and having a low gamma radiation dose compared to others^ight be the best choice. Although it is believed that the strongest of such sources which can be available is a 25-curie americium-2ill C 1J we managed to get a 50 curie one from Amersham International PLC. This is the strongest source of its own kind in the world. In this paper we report about the design and construction of a sophisticated irradiation facility which we did for the above source and now has become ready to use. We also report about the possible applications C2]and finally we give reco^irsndations to those laboratories which are interested in such facilities.

2.Design and Construction of the system

The source was delivered with a transport container' which satisfied the IAEA regulations,Safety Series No.6,1973,revised edition. On arrival we did a camprehersive dosimetry and we found the surface dose rate of about 40 mRem/hr and 2.5 mRem/hr at one metre. The source itself has a stainless steel double encapsulation Argon arc weld and engraved to OCR*!. It is cylindrical in shape having l\9 mm diameter and a length of 86 mm. The neutron rate output is about 2X10° n/sec. The source shape,strength and the measured neutron rate are all promising to get a reasonable relatively homogeneous flux of slow and fast neutrons for various applicat­ ions if a suitable system is designed. The most important factors in such designs is not only the safety regulations which should be taken into account, but also the versatility of the system. According to safety

180 regulations the surface dose rate of the system should not be more than 2.5 mRem/hr. Taking all the above facts into account it was decided to design a cylindrical tank and to use paraffin as the moderator rather than the liquid moderators which have the leakage risk. Calculations were performed taking all the attenuation factors into account. The results show that the internal diameter of the tank, i.e.the diameter of the paraffin moderator should not be less than 124 cm. Since this means a relatively heavy weight it was decided to make the tank from steel with 6 mm thickness to be able to stand the weight. A hole with 5 nm diameter was made in the middle therefore one would be able to insert the source in the middle of the tank. Special arrangements have been made to fix the sounce and two bars from perspex have been made,one to be inserted at the top and another at the bottom of the source to protect the personnel from the hazardous radiation. For slow neutron activation analysis,neutron dispersion measurements in paraffin and teaching purposes 12 holes altogether were made on 5 circles with different radia taking the source center as the center of the circles. The diameter of each hole is 46 mm and the radius of the first circles which has got two holes at right angles on it,is 10 cm and it is predicted that one would be able to get a flux of about 5X10 n/sec/cm^ at the sample location parallel to the source in these two holes. The whole system has been located on suitable wheels and special handles have been made for moving it around. To have access to high flux of fast neutrons two holes have been made at right angles on the surface of the cylinder in a way that with a special perspex bar, targets can be put in various distances from the source. Neutron radiography and fast neutron activation analysis can easily be performed by using these two holes and their conjunction perspex bars.

3.Conclusions and Remarks

With a small budget,we have managed to design and build a proper and sophisticated system which can locate the strongest Am-Be neutron source of the world. It can easily and effectively be used for various applications,research,teaching and training purposes. Safety regulations has been taken into account at its highest standards. Apart from safety, the system is very versatile and easy to use. Due to its versatility, safety reliability reasonable flux and also from the economical point of view,it is highly recorauended to poor laboratories,research and training institutions who are interested in neutron activation analysis as well as other applications of neutrons. Finally the author wishes to thank Mr. Fereydooni and Mr.Katoczi for their usuful comments regarding the safety standards and also Mr.Shsani for his patience during; the drawing of the design.

References

1. IAEA Vienna meeting report May (1985) P. 3 2.Bardell,A.G.,NPL News Winter (1984-85) Mo.362 P.l6

J81 THE POSSIBILITY OF AGGREGATE IDENTIFICATION IN CONCRETE BY PHOTON-ACTIVATIPM-ftKftLYSIS < PA A)

M. Rommela>, 3h. Gehrbish3*, E.-J. Langrock1'

17 University of Technology Leipzig, PF 66, Leipzig 7030,German Democratic Republic z> Laboratory Nuclear Research of the Mongolian State University, Ulan Bator, Mongolian People's Republic

For diagnosis of buildings with regard to material resistance it may be very important to identify the aggregates from concrete. Besides the main component of silica there are some minor and trace elements whose concentration depends from the various joining locations.

The aim of this work was the identification of aggregates by detersiii nation of minor Br\d trace components using a photon beam from the MIKROTRON PIT 22 like in JINR Dubna.

So we irradiated concrete powder samples of about 3g for each sample 4 hours with 22 MeV photon heam and an intensity of 12 fiA. The irradiation was carried out in parts of 10 samples together with two standards. As monitor we used gold foils before and behind each sample.

For y-spectroscopy we used a thin 6e(Li) detector <2. i on3} and a large one (70 cm35}.

The measuring of v-—spectra carried out two times for each sample inside one day after irradiation permits the determination of 13 elements. These elements are Sr, Cs, Ce. U, Th, SIT., Ni , Ti , Ca, 3a, Kb, Zr and Pig. The investigations of aggregates from 4 mining locations shows different content of some minor ana trace elements. For ei'/smple cerium we only find in "Pechstein" (0.0178 "/.) . Rubidium and circonium seems to exist only in "Kiesel— schiefer"

182 Facility for Prompt Gamma Activation Analysis of Biological Samples with Cold Neutrons at the KFA-Julich

M. ROSSBACH, M. STOEPPLER Institute of Applied Physical Chemistry, ICH-4, Nuclear Research Center, KFA Julich, 5170 Julich, FRG

An external neutron guide hall (ELLA) was installed 1983 adjacent to our 23 MW Research Reactor DIDO at KFA in

Julich. As the guide tubes are internally lined with ^Ni a cold neutron fluence of up to 5 • 10° N/cnrs is available about 50 m away from the reactor core with the cold source operating on liquid hydrogen. The energy distribution of the neutrons lies in a rather narrow band between 2 and 6 A (see figure 1) with a Cd ratio for Au activation of 620:1. This situation is particularly advantageous for prompt gamma activation analysis (PGAA) experiments [1] because of the exceptionally low background and the rather high fluence rate of low velocity neutrons (G ~ 1/v) which on a total illuminated area of 50 cnr makes ~ 6 • 10J usuable neutrons per second [2]. Although PGAA was used for the determination of single elements like B, S, Cl, N and Cd in a number of matrices including in vivo determination in humans the quick and cost effective technique never had been explored for its usefulness for multielement specification in environmental and biological samples. After a number of preliminary experiments it was evident that the main drawback of the method seems to be the huge scattering cross section of hydrogen thus producing an appreciable flux depression in thick biological samples.

183 Scattered neutrons are not only lost for absorption . • • in the sample but produce an undesired background radiation field by interaction with structure material of the sourrounding. To minimize those unwanted side effects an efficient lead shield for the gamma X-HPGe detector has been installed and will be described allong with an appro­ priate sample chamber that reduces background radiation and accounts for the amount of scattered neutrons. In a first attempt a quantification of elements in SRM's and specimen bank materials is undertaken and will be compared to detection limits estimated earlier [3]. Progress in the development of this multielement technique will serve not only for the quantification of trace and compositional elements in bulk materials but will be helpful in the examination of surfaces and in kinetic studies on inter­ acting compounds.

2 xlO to en iwd" ; m *~4 /Art •«o * m ir o .. • fe* ""' tri (£) •"" ft i tA «£ /v (\ tn *—" 1 i e> r^-. Li­ / \ es c—o« I/ #— 20- i \ •' h / f • /inN A!

10- M11 '< l»\!\ i \l l I A Al ] J n /T u 3 3.0 5,0 6,0 MA) 2.< 4.0 J

Fig. 1: Time of flight spectrum of the neutron beam at NL1 in ELLA, KFA from March 21st 1988

18-1 References

[1] R.M. Lindstrom, R. Zeisler, M. Rossbach: J. Radioanal. Nucl. Chem. Vol. 112 No. 2 (1987) 321-330

[2] M. Rossbach, 0. Scharpf, W. Kaiser, W. Graf, A. Schirmer, W. Faber, J. Duppich, R. Zeisler: Nucl. Instr. & Meth. in Phys. Res. B35 (1988) 181-190

[3] M. Rossbach, R. Zeisler, R.M. Lindstrom: Proc. of Int. Symp. "Utilization of Multipurpose Research Reactors", Grenoble 19. - 23. Oktober 1987. IAEA-SM-300/16, VIENNA 1988

185 RADIOCHEMICAL NAA OF PLATINUM GROUP ELEMENTS IN BIOLOGICAL AND ENVIRONMENTAL SAMPLES

M. Rossbach Institute of Applied Physical Chemistry, ICH-4, Nuclear Research Centre, KFA Jiilich, 5170 Jiilich, FRG

A.R. Byrne Dept. of Nuclear Chemistry, "J. Stefan" institute, 61111 Ljubljana, YU

Naturally occuring levels of the platinum group elements and gold (Ru, Rh, Pd, Re, Os, Ir, Pt and Au) in biological materials are supposed to lie in the nanogram to picogram range or below. Because of great problems with contamination and/or sensitivity of available methods, only very few data on their concentrations in biological tissues and environ­ mental materials have been reported in the literature(). Although the problems encountered are real, knowledge of the base line levels of these elements is becoming urgent as the widespread introduction of catalytic exhaust converters could result in increased ambient levels of these metals, as well as their increasing use in bioengineering as impacts and electrodes, and as chemo- or raditherapeutic agents. The fate and pathways of these compounds in the environment

186 deserves thorough investigations. Formation of biologically- active species cannot be excluded. Neutron activation analysis, particularly its radiochemical mode, offers the most promising approach for sensitive detection of most of these elements. The method used in this work consists of a pre-irradiation preseparation of the elements on a selective ion exchange resin which, after appropriate neutron irradiation, is destroyed and single and group radiochemical separations applied and fractions counted using well-type HP Ge or low energy detectors, with and without Compton suppression. This approach was verified for certain of the more amenable elements (Au, Pd, Ir) by totally post-irradiation methods, where sufficient sensitivity is available to avoid a pre- • separation. Preliminary results on biological reference materials and other environmental samples will be presented.

References:

1) P. Schutyser, A. Govaerts, R. Dams, J. Hoste, J. Radioanal. Chem. 32 (1977) 651. 2) R. Zeisler, R.R. Greenberg, J. Radioanal. Chem. 25. (1982) 27. 3) A.R. Byrne, Mikrochim. Acta 1 (1981) 323,

187 ANALYSIS OF BRAZILIAN SNAKE VENOMS BY NEUTRON ACTIVATION ANALYSIS

M.Saiki, M.B.A.Vasconcellos, J.R.Rogero Brazilian Nuclear Energy Commission - Nuclear and Energy Research Institute (IPEN-CNEN/SP) P.O.Box 11049, CEP 05499, Sao Paulo-Brazil

In Brazil accidents with snakes are still common in non-urban areas. An average of 70 000 accidents are estimated per year. Treatment still depends almost exclusively on injection of antivenim serum.

It has been shown that the hemorrhagic activity of snake venoms can be related to the presence of ions like Ca, Mg and Zn. Friederich and TuL_l_) analyzed by atomic absorption venoms from snakes of different geographical origins and found the metals Ca, Mg, Zn, Na and K in all of them.

Bjarnason and Fox also pointed out that metals can play important roles in the venom protein structures stabilization.

The determination of inorganic components in snake venoms could be important from the point of view of the biochemical characterization of snake species and also as a contribution to the knowledge of the role of metals in the pharmacological action of the venoms.

Neutron activation analysis is highly suitable to be applied to this kind of study, but very few papers can be found in the literature about the use of this method in the characterization of snake venomsL_3 _J .

In the present paper, the method of instrumental neutron activation analysis (INAA) was applied to the determination of inorganic compo­ nents in venoms from two different species of Brazilian snakes: Bothrops jararacussu and Crotalus durissus terrificus.

The procedure consisted of irradiating from 50 to 100 mg of crude and air dried venoms during different periods of irradiation, of 10 minutes under a thermal neutron flux of about 1011 n.cm~2.s-1 and of 8 hours under a thermal neutron flux of 1013 n.cm~2.s_1, in the IEA-R1 nuclear research reactor. During weighing, special care was taken not to breathe the venoms or allow them to be in contact with the skin.

Synthetic standards were prepared in the laboratory for the elements of interest and irradiated together with the venom samples. Suitable amounts of pure reagents containing these elements were dissolved and pipetted on pieces of Whatman n° 40 analytical filter paper.

188 After convenient delay times, samples and synthetic standards were measured in a gamma-ray spectrometer consisting of an ORTEC GEM 20190-P Germanium detector coupled to a 4096-channel Hewlett-Packard analyzer. The resolution of the detector was of 2.1 keV for the 1332.5 peak of 50Co.

The analytical conditions usea allowed the determination of the elements: Br, Ca, CI, Co, Cs, K, Na, Rb, Sb, Se and Zn in the venoms, in concentrations ranging from % (Na, K) to ppb (Co, Cs). The other elements were in the ppm range.

The elements: Mg, P, Al, La and Mn were also detected but not quantified yet.

The accuracy of the method was checked by analyzing the reference materials Bowen's Kale (IUPAC) and Bovine Liver (NRS SRM 1577a).

The main interference in the analysis of short-lived radioisotopes is the high activity of 2<+t?a. Due to this fact, irradiations with cadmium filter are under investigation.

The elements Ca, CI and Zn were also found in relatively high amount as noted by other authors.

Other venoms from different Brazilian snake species are intended to be analyzed by NAA to make a comparative study of their metal contents.

CO Friederich, C. , Tu, A.T. , Biochemical Pharmacology, 20 (1971) 1549-1556. L2j Bjarnason, J.B., Fox, J.W. , Journal of Toxicology-Toxin Reviews, 7 (2) (1988-89) 121-209. GO Moav, B., Gitter, S. , Nellwart, Y., Amiel, S., Radiochemical Methods of Analysis, Proceedings of a Symposium, Salzburg, Austria, 1 (1964) 205-216.

189 MICROELEMENTS CONTENT IN LEAVES AND FRUITS OF HIPPOFHAF RHAMNOIDES (£) PLANT DETERMINED BY NEUTRON ACTIVATION ANALYSIS

Maria Salagean* Ana Pantelica* I. Brad** *) Institute of Physics and Nuclear Engineering, P.O.B.MG-G Bucharest- Romania **)Faculty of Nature Sciences, University Craiova, Romania

It is well known that leaves, fruits, stems and roots of Hivvophae rhamnoides {&) plant contain very numerous ac - tive physiological substances with stimulative effect for huinan beings: and animals.

Besides proteines, glucides and fatty acids, the important quantities of essential aminoacids , vitamines (. C , B-j_, Bg , Bg, E, F, P)., serotonine, carotenoides with value of A pro- vitamine,various mineral substances, essential macro- and microelements,enzymes, etc. are contained in this plant.

In this work the concentration of Ca, K, Na, Fe, Zn, Sr, Ba, Rb, Br, Cr, Ni, Co, As, La, Th, Sc, Cs, Se, Sm, Yb, Hf, Sb , U, Eu, Au (order of their content decrease) has been deter - mined in leaves and fruits by instrumental neutron activa - tion method. The concentration values are reported to the ashed samples. A comparison of microelement contents obtain­ ed for the normal fruits and for fruits which the oil was extracted has also been made.

The irradiation has been performed at VVR-S reactor at a 3 x 10 ^n/cm .s flux and the measurements have been carried out using a Ge(_Li) detector.

190 The importance of macroelements and microelements Fe, Co, Ni, Zn, Sr, Cr, As, Ba, Br, Rb, Au etc. in the metabolic proces­ ses is pointed out. Different metalic ions could be consi­ dered as "mineral vitamines" beeing indispensable in the enzymatic activity in the organismes.

Due to this complex composition this plant constitutes an excelent natural polyvitamine. In many countries is success­ fully used both in the alimentary and pharmaceutical indus - tries.

191 THE DETERMINATION OF ARSENIC, MERCURY AND SELENIUM IN MALAYSIAN SEA FOODS BY INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS

Sukiman Sarmani, Abdul Khalik Wood and Zaini Hamzah Department of Nuclear Science National University of Malaysia 43600 Bangi, Malaysia.

Malaysia is a coastal state, with a 48,000 km coastline and a land mass of 331,500 square kilometers. About 100,000 fishermen are directly dependent on the coastal fisheries resources, landing about 0.5Mt of fish annually. Fish and fisheryproductssupply about 75%of the protein requirement of the population. Inland industrial activities may discharge toxic metals in their effluents. Coastal fishes in turn may accumulate toxic metals from coastal drainage. It is therefore very important to determine the toxic element contents of coastal fishes as they are major sources of protein in sea foods.

The sea foods analysed were prawns, squids, indian mackerel, Spanish mackerel and catfish. Fish samples were bought from coastal fishermen at the landing jetties along the West Coast of the Malay Peninsula. The samples were kept refrigerated and brought to the laboratory. The samples were then cleaned and were kept at shelf freezer at -15 C and then dried in a freeze dryer. The dried samples were then homogenised and kept in plastic bottles for analysis.

About 200 mg of each sample was packed in prcclcancd quartz vial. Standard was prepared from standard chemical solution. Standard and samples were irradiated in a 1MW TRIGA Reactor for 8-36 hours. The gamma activities of the samples were measured by a high resolution gamma spectrometer consisting of ORTEC HPGe adctector with a resolution of 1.8 kcV at 1322 keV gamma line and an efficiency of 20% relative to 3"x3" Nal(Tl) detector. The detector wcas connected to ORTEC 472A Spectroscopy Amplifier and Nuclear Data ND66 Multichannel analyser calibrated at 0.5 keV per channel. Peak identification and evaluation were carried by dedicated PDP11 combus computer connected to the system. Arsenic was analysed via the 559 kcV peak of As-76, antimony via 564.0 keV of Sb-122, mercury via 279.1 keV of Hg-203 and selenium via 264.6 keV of Se-75. Correction was made for the overlapping peaks of 279.1 keV of Hg-203 and 279.6 keV of Se-75.

Accuracy and precision of the analytical technique used was validated by analysing Mussel Tissue (NIES) and Fish Muscle (IAEA). The analyses consistently gave comparable results.

Table 1. Concentrations of toxic metal in mg/kg wet weight

Element Squid Mackerels Prawns

Arsenic 2.44-6.82 0.67-5.77 0.95-6.05

Mercury 0.08-0.34 0.23-0.25 .08

Antimony .05 .3 .45

Selenium 0.69-1.15 0.51-0.74 0.30-0.73

192 Results of the study is shown in Table 1. The heavy metal contents of prawn and squid were generally much higher than those found in fish muscle. The arsenic concentrations of lresh water fishes are in the range 0.06-0.9 mg/kg, 'izty much lower than in coastal fishes. The concentraionsof arsenic were higher when compared to other toxic metal concentrations in the samples analysed. Further study is being carried out to look at the arsenic concentrations in bivalves and several species of marine fish.

Under athe Malaysian Food Regulation 1985, the maximum permissible limit for arsenic was set at 1.0 mg/kg while for others at 0.5 mg/kg. Our results indicated the consumption of squid and prawn was not permitted under the regulation. The concentrations of antimony, mercury and selenium were still within the limits set in the regulation. The average consumption of fish as shown in the studies by the Institute for Medical Research by a Malaysian is about lOOg daily. The maximum intake of arsenic derived from fish consumption can be estimated at 0.68 mg/day. Symptoms of arsenic toxicity only appear if a person continously ingested 5 mg As daily. Toxic level of arsenic ingestion through fish will be achieved if a person consume about 1 kg offish daily.

The toxic metal contents of squid muscle varied from location to location. Generally, where there is extensive industrial activities inland, the toxic metal contents of squid samples collected in that coastal area were higher. Apart from industrial activities, logging of coastal forest may also increase heavy metal contents of coastal waters. About 50% of the coastal forest in Peninsular Malaysia has been logged with a view to conversion to other uses such as aquaculturc, agriculture, fresh water impoundment and tin mining. Logging may result in the release of trace elements from the pcatland into estuaries rccieving peatland drainage. This has been shown to occur in the peatland areas of Nothern Carolina, USA [1].

[1] Pace, C.B., DiGiulio, R.T., Env. Pollut., 43 (1987) 301-311.

193 DETERMINATION OP RARE EARTH ELEMENTS IN MINERAL RAW MATERIALS AND RARE EARTH INDUSTRY PRODUCTS DY NEUTRON ACTIVATION ANALYSIS

Shmanenkova G.I., Scheikova V.P., Uritskaya T.P., Vollcova L.V. State Institute for the Rare Metals "GIREDKET", Moscow, USSR

Rare earth (RE) metals and their compunds are widly used in various "branches of science and engineering. Analytical control is dwisnded at all stages of RE production, begin­ ning with the RE content estimation in mineral raw materi­ als up to the high, purity fjnal products specification. Neutron activation analysis allows to determine RE ele­ ments (REE) with high sensitivity. However, the realizati­ on of this method possibilities for REE determination in the instrumental modification is not always because of the mutual effect of the RE radionuclides and one of the asso­ ciated elements.

To increase the efficiency and information capability of the neutron-activation analysis the REE were separated from other constituents and one from another using extrac­ tion chromatography.

For the extraction of the whole group of RE elements from the mineral raw materials the TBP-nitrate salt solution extraction system was used.

For the following separation of the RE elements into frac­ tions containing individual RE elements or their groups not

194 interfering their f'-spectrometric determination the HDEHP-HC1 system was applied.

!Ehe dame extraction system was used for RE impurities sepa­ ration from high purity RE compunds.

.Analysed samples was irradiated before the separation in nuclear reactor with 1,2 • IO15 - 3,5 • 10 3H/cm c thermal neutron flow for 20 hours.

The RE radionuclides activity was measured with iT-spectro- meter having semiconductor detector of the 20-30 cm capa­ city.

Cesium"157 If-line resolution (E = 0,662 MeV) didn't exceed 4 KeV.

Combination of the developed RE extraction and separation procedures with the following )f-spectrometric analyses of the fractions containing RE radionuclides allows to deter­ mine their content with the lower limit of concentration range of 10"5 - I0"8#.

The relative standard deviation was 0,2- 0,3 .

195 SHORT AND LONG-PERIOD VARIATIONS OF THE ELEMENT COMPOSI­ TION OP PLANTS AND SOIL IN LENINGRAD

Irina Shtangeeva Institute of Earth Crust 199034 University of Leningrad, Leningrad, USSR

Neutron-activation analysis (NAA) seems to be one-of the most perspective methods of solving ecological and biolo­ gical problems nowadays.

Our work included detailed examination of element composi­ tion of two widely spread in Europe and Asia plants, Ely- trigia repens and Plantago major as well as their growing soil. The sampling of the plants and soils (from the hori­ zons 0-5 cm) was carried out during 3 vegetation periods on different sites both in a big industrial city (Lenin­ grad) and in a sufficiently ecologically pure zones (fo­ rests, countryside far from the city).

The sampled plants were carefully washed to remove dust and soil particles, were dried at room temperature. Burn­ ing was not performed, the plants were analysed in their natural state. The samples were placed in vessels made of extra-pure quartz the later having impurities concentra­ tions several orders less than in the samples tested. Measurements were made against standard multi-element sam­ ples of vegetative origin. Both thermal and epithermal ne­ utron radiation was used. The samples were under radiation for 2-3 days with the neutron flow density of 5-10.IO1^ neut.cm-^.sec .

The measurements were carried out by means of an instrumen­ tal variant of NAA provided with 2 semiconductor detectors

196 a Ge(Ii) one (volume = 21 cm3), resolution 2,1 key for 1332 kev) and an extra-pure Germanium (v = 60 mirP, resolu­ tion 0,35 kev for 122 kev). The total number of elements detected was 34 (Ka, K, Ca, Sc, Gr, Fe, Co, ITi, Zn, As, Se, Br, Rb, Sr, Zr, Ag, Gd, sb, Cz, Ba, la, Ce, Ed, Sm, Eu, Tb, Tm, Yb, Hf, Ta, Au, Hg, Th, U).

The absolute majority of elements under consideration is rather unevenly distribution in different organs of E.re- pens and P.major. For example, roots are enriched with ma­ ny chemical elements in comparison with other organs. It is supposed that roots play the role of a certain barrier preventing heavy metal from penetrating stalks, leaves and semen. Moreover, stalks and semen are characterised by low variations in concentrations of these elements. Thus, plants obviously posess certain defence mechanisms, pre­ venting excessive heavy metals from penetrating generative and reproductive organs.

Concentrations of chemical elements in plants and soil va­ ry, especially in time. 24-hour variations of the elements concentrations a re more pronounced compared with the sea­ son variations. In the system soil-roots-generative organs- reproductive organs a regular redistribution of separate elements takes place, due mostly to photosynthetic and re­ productive processes, the ratio between concentrations in plants and in soil being relatively constant. Changes in concentration of a certain element are followed immediately by changes in concentration of other elements.

Correlations between chemical elements in soil and diffe­ rent organs of E.repens and p.major proved that definite associations of elements can be observed that are typical for a definite organ of a plant and a definite type of soil.

197 • HIGH-FLUX NUCLEAR REACTOR IN ANALYZING SUPER-PURE METALS AND SEMICONDUCTORS

SHULEPNIKOV M.N., FIRSOV V.I., KISELIOVA T.T., RABINOVICH B.S., SYSOEVA N.S., KONDRATIEVA G.I.

THE STATE INSTITUTE OF RARE METALS 109017 MOSKOW USSR

THE RECENT YEARS HAVE SEEN CONSIDERABLE PROGRESS IN THE PRODUCTION OF SUPER-PURE MATERIALS. THIS RESULTED IN A SUBSTANTIAL REDUCTION IN THE NUMBER OF IMPURITIES OBSERVED IN ALL METHODS OF ANALYSIS INCLUDING THE NEUTRON-ACTIVATION.

APPLICATION OF A HIGH-FLUX NUCLEAR REACTOR (1.1014n.s_1cm~2) AND SOME MEASUREMENT PROCEDURES MADE IT POSSIBLE TO INCREASE THE SENSITIVITY OF THE INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS (INAA) OF SUPER-PURE

Si, Ge, Ti, Pb, Al, Nb, AND OTHER ELEMENTS. DETECTION LIMITS (DL) FOR 20-40 IM PURITIES WERE LOWERED 20 TO 200TIMES, WHILE FOR SOME ELEMENTS EVEN 1000 TIMES,THUS REACHING THE VALUES OF 10~8-10" 13WT%/1/.

THE MAIN PROCEDURE CHARACTERISTICS ARE AS FOLLOWS: IRRADIATION TIME UP TO 200 HOURS: MASSES Si,Ti, Pb UP TO 10-15 g: MASSES Ge, Al AND Nb UP TO 5-8 g: TIME OF INDUCED ACTIVATION MEASUREMENT UP TO 10-12 HOURS. ACTIVATION MEASUREMENTS WERE PERFORMED WITH A 155-cm3 Ge-DETECTOR HAVING A 1.9 keV-60Co ENERGYTE SOLUTION. THE ADOPTED ANALYSIS CONDITIONS CAN TO SOME EXTENT CHARACTERIZE UTMOST POSSIBILITIES OF THIS TECHNIQUE IN THE INAA AT THE PRESENT STAGE OF ITS APPARATUS AND TECHNIQUE POTENTIAL.

CHARACTERISTIC .FEATURES OF THE ANALYSIS, WHEN SAMPLE IRRADIATION WITH HIGH-DENSITY NEUTRON-FLUX IS DURABLE IN TIME AND PARTICULARLY THE RADIATION SAFETY PROBLEMS, SAMPLE REPACKAGING CONDITIONS, NEUTRON FLUX MONITORING AND OTHERS HAVE BEEN STUDIED.

DISCUSSION IS FOCUSED ON PECULIARITIES IN OBTAINING AND INTERPRETING SPECTROMETRIC DATA AT MANY-HOUR MEASUREMENT OF RADIATION. IT IS SHOWN THAT VALUES OF THE MEASURED ANALYTICAL SIGNALS FROM THE IRRADIATED SAMPLES OFTEN TEND TO BE WEAKER THAN THE DETECTOR BACKGROUND GAMMA- LINE VALUES.

198 FURTHER, DISCUSSED IS THE PROBLEM OF APPEARANCE OF A BLANK EXPERIMENT CORRECTION IN THE INAA WHILE DETERMINING IMPURITY CONTENT AT A LEVEL CORRESPONDING TO THE 10~ 9- 1(f 13 WT % IMPURITY CONTENT.

AS EXEMPLIFIED BY A HIGHLY PURH Ge ANALYSIS, COMPARISON IS MADE OF POS­ SIBILITIES FOR INSTRUMENTAL AND RADIOCHEMICAL ALTERNATIVES OF THE ME­ THOD AND THE ANALYSIS WITH A PRELIMINARY IMPURITY CONCENTRATION FOLLO­ WING THE AUTOCLAVE BASE BREAKDOWN. TOP PRIORITY IS GIVEN TO CONSIDERING LIMITATIONS IN EACH OF THE TECHNIQUES.

DISADVANTAGES OF INSTRUMENTAL AND RADIOCHEMICAL ANALYSIS TECHNIQUES ARE SHOWN AS EXEMPLIFIED BY A SEMICONDUCTOR SILICON ANALYSIS. DISCUSSION GOES ON A POSSIBILITY AND NECESSITY FOR UNIFICATION OF INSTRUMENTAL ANA­ LYSIS PROCEDURES IN RELATION TO A LARGE NUMBER OF PROCEDURES WITH VERY SIMILAR ANALYSIS PERFORMANCE CONDITIONS.

CONSIDERATION IS ALSO GIVEN TO PROSPECTS FOR HIGHLY PURE MATERIAL ANA­ LYSIS AT SAMPLE IRRADIATION WITH A FLUX OF NEUTRONS HAVING ESSENTIALLY DIFFERENT SPECTRUM CONTENTS, IN PARTICULAR, DURING IRRADIATION IN CHAN­ 15 1 _2 NELS OF A FAST-NEUTRON REACTOR (Fn=1.10 n.s" .cm , En>40eV).

COVERAGE IS GIVEN TO BENEFITS AND DRAWBACKS IN ANALYSIS OF SILICON, TI­ TANIUM, LEAD, ALUMINIUM AND GERMANIUM BEING IRRADIATED INSIDE CADMIUM- COATED REACTOR CHANNELS WITH A FLUX DENSITY OF EPITHERMAL NEUTRONS OF 1.1013n.s~1.cm_2/2/.

REFERENCES /1/KISEILIOVA T.T., FIRSOV V.I., SHULEPNIKOV M.N. JOURNAL ANAL. CHEM. 43, No.2 (7987) P.P. 256-262.

Ill FIRSOV V.I., SHULEPNIKOV M.N., KISELIOVA T.T., RABINOVICH B.S. PROCEED. CONF. „ANALYSISOF SUPER-PURE MATERIALS". CSSR, 1988,71-73.

199 NEUTRON FLUX FLUCTUATION AND THE PRECISSION OF NEUTRON ACTIVATION ANALYSIS

Octavian Sima, University of Bucharest

Suposse a sample of mass M, atomic mass A, is activated during the time interval E0,TJ in a mean flux

(1) m=gC£M/A W' y- (l-exp( -XT)) (exp( -ACS^T) )-ejcp(-JU%-T))) = K M (p From this the mass and its standard deviation are usually computed by (2) M = m/K/$ ; (3)

200 any time interval can be achieved. Usually a less precise information is sufficient, namely the functions -, T T [4) f(t) = J" P(k) kV ffi J1J (t|k), where fll)(t |k)=fdt .. fdt f(t..t|k) 1 ^~ i .oo 1 I k 1 k k=l i=l k-1 integrals,i-th missing (5) f (t,t') = ^P(k) ^f •'•' (t.t'U) k=l i/j (i,j) J J where f (t; ,t- ) = Jdt, .. Jdt^ flt^.t^lk) (k-2 integrals,i-th and J-th- missing) Then it can be proved C13 that the mean and standard deviation of the number n of nuclei disintegrated durina the time interval CS. .S, 1 is: _ T ^ " 1 i (6) n = Jdt Jds p(t,s) f(t)

X T T *2 S2 (7) 5 = n + jdt /dt' /ds Jds' p(t,s) p(t',s') Cf (t,t' )-f (t) f(f)3 0 o S{ Si The first term in (7) is the usual Poisson term; the second takes into account the correlations during the activation process. This additional term arises just like in the.well-known variance-to-mean method of Feyn- mann et al used in reactor noise studiesC23. l In order to express G~- as a function of flux fluctuations on the basis of- formula (7) the flux autocovariance function C , (Z) is needed, and this must be specified theoretically or measured experimentally for each situation of interest. In lack of more specific information, we consider 2 cases: DWe suppose that the numbers of neutrons that pass through a sur­ face at different times as well as the numbers of neutrons that pass through nonoverlapping surfaces are uncorrelated. To avoid some diffi­ culties connected with the limits when At6 and ASC tend to zero, we define the flux as a stochastic process by the ratio of the number of neutrons that pass through the surface ASC during At0 and the product of AS„ and At„ ; AS„ and At0 are small, but fixed . Then it follows approximately that: C- = "m* (1 + DU,T) m 6.* )

where D(X,T) =AAt0 /2 (l+exp(-J.T)) / (l-exp(-i-T)) AS0 / A S

201 £ = —t is the relative standard deviation of flux, measuring flux fluc- tuations during the activation process, AS is the area of the sample and m is given in (1). (Note that the above E^ and —— in (3) refer ? to different quantities).

For a medium mass nucleus with 6^"-lb, k ~s~ , Atfl=ls, A S =lcm

a in a sample with M~1IMJ activated in a flux cf> -~' 10 n/cm /s and £,»~10" the additional term is of the order of the usual Poisson term in (8). 2) We consider Markoff processes, C^ (r)*»exp( - ot|r | ) .corresponding to a lumoed parameter model of the reactor C33 with delayed neutrons neglected. Then : (9) 6^,= "m (1 + C(«,A,T) ni £^ ) , where: C(*A,T;= ^/( ^-oi2)C(A+a.jexp(-2J.T) -2k exp( -(X + «)T)+i-cO/Cl-exp( -LT)3 For A.T»1, C=X/(X+oC) and the effect is more important for small ^Vx. • ^or a reactor in which flux fluctuations are dominated by the i 6 _4 statistics of the fission chains a.^10 -rlO s , and this term can be neglected, but in power reactors 6( can be of the order of s and the additional term must be considered. In both cases considered, the additional term can be neglected if ni is small (if 01/4*' or 9 are small,the activation or the detection processes are rare events, that is Poisson processes). In conclusion, neutron flux fluctuations during activation time increase the standard deviation of the measured number of counts,in­ creasing in this way the imprecission of mass. The additional term, which is proportional to the square of the product of the number of counts and the relative erorr £,. of the flux, arises because the processes in reactors deviate from Poisson processes. The imprecission in the value of the mean flux Sjr also contributes to the imprecission of the mass value,but the two contributions must be treated separately. References CID.O. Sima, St. Cere. Fiz. 39(1987)177 (in Romanian) C23.J./-.. Thie, Reactor Noise, Rowman and Littlefield, New York 1963 C3D.J.Lewins,Nuclear Reactor Kinetics And Control,Pergamon,Oxford 1978

202 STUDIES ON THE NON-UNIFORMITY AND REPRESENTATIVE SAMPLING BY NAA

Smakhtin L.A., Shevaldin O.A. Karpov Institute of Physical Chemistry Section Obninsk, USSR

Uniform mixing all the components of powder mixtures is one of the most important conditions for obtaining the product with required properties. For reliable estimation of the degree of non-uniformity of the mixture of definite compo­ sition a great analytical work must be made (15-20 samples of each mixture with analyzing several times). The weight of the chosen samples is not high (1-10 mg) as non-unifor­ mity destribution of any mixture component is growing writh decreasing the sample mass. Thus the applied method of ana­ lysis must be both sensitive and high efficient. It is de­ sirable that it be nondestructive. INAA satisfies this re­ quirements.

The non-uniformity of the distribution of minor components in synthetic granates, ferrites, glass charges, in some en­ vironmental materials was studied by INAA [1,2].

In this works the systematic errors aresing here and the ways of their estimation were concidered. It has been shown that if in studying non-uniformity the averadge concentra­ tion of the studied mixture component must not he determi­ ned, the directly measured values J. ..-intensity of analyti­ cal photo peaks may "be used without monitoring the neutron flux.

203 The estimation of the degree of non-uniformity is important not only for developing the process of obtaining uniform mixtures, but for the estimation of the value of a represen­ tative sample -At.in the analysis of nonhomogeneous materi­ als. On can show that

where S^^^^ and SPfPepPfi are a relative standard de- viation vercus non-uniformity and reproducibility for mass p. determined by INAA and dispersion analysis; f-j) [ is Fi­ sher criterion for confidential probability P and degrees of freedom f^m-1 and f^00 and m is the number of analy­ zed samples of the material studied; k depends on method er­ rors, conditions of making analysis and concentration of com­ ponent to be determined.

The estimations of the minimal representative sample for two extreme- cases kp > kp.» 1 and kp.< kp << 1 will be P'l&Pi'(9S{non-un/i /ji,Z€Pl,i)s-Ffi^ (2)

2 Pi 2> 3Pi • (Si, non-un,l /J2j zcpz, i) • fj> i (3) Oeher parameters being equal in (2) and (3) p_> p_. For in­ termediate values (1+kp.)/(1+kp ) if k known, value p can be obtained from the equation 3 n El - 9PI'&»O>2ZMJ- . ItKEL - n ^ K f7,zePz,L Fp/fK If k is not known, p_ must be taken as a representative sam­ ple, because it is the largest and does not depend on lc

1 Smakhtin, L.A., Kurinov, A.D., Merkulov, A.V., Sinays- ky, II.M., J. Radioanal. Chem. , 26 (1975) 127-134. 2 Smakhtin, L,A., Kurinov, A.D. , Shokel, E.S., fi/Ierkulov, A.V., Zh. Analit, Khim., 36 (1981) 78-82.

20-1 THE USE OP UNIVERSAL COMPARATOR METHOD IN LARGE-SCALE NAA

Smakhtin L.A., Pilippova N.V., Miglina N.V., Shokel E.S., ' Shutova I.N. Section of Karpov Institute cf Physical Chemistry- Obninsk, USSR

In comparator method the intensities of interesting radioi­ sotopes Dli may he expressed as a product of some multi­ pliers :

where 6(1,1 is a function of neutron flux parameters, nucle­ ar-physical characteristics of nuclear-targets and formed radioisotopes of the interesting element and the elements of the comparator. SI/^KX is a function of characteristics of the spectrometer used. £l and£/aare the efficiencies of registration of analytical y -lines of the interesting isotope i and j-isotope of the comparator.

For simplicity and unification of the comparator methods we proposed to obtain the calibrating function of changing re­ lative efficiency of the registration £zt£ for any geometry of measurement (for any detector) from ^-spectrum of com­ parator isotopes directly. In this case it is necessary that at least one of the comparator isotopes have intensive y -lines in a wide region of energies ( ° Ir, -* Eu, Ta, etc.). Prom the function obtained £ relaf(E) it is easy to determine £l /SK,P for any ^-line pair. dil,P were calcula­ ted from the reference data for y -lines of radionuclides which are interesting for NAA.

205 In determining elements by their short- and mean-life radi­ onuclides the comparators ^ V and %a were used. Two-iso­ tope comparator ( yZn, ^ Eu) was used for long-life radio­ nuclides. The comparators were made by two ways. In the first case the comparators are as a kind of dry residue parts of titrated solution of the salt of elements used. In the second case the comparators were made according to the method developed by us C13 as a powder Si02, obtained from purified tetraethoxysilane.

In the case of the large scale analysis, e.g. geological materials, two comparators and two geological standards (GS) are irradiated simultaneously.

The spectra of the comparators and GS are measured before measuring spectra of the samples. The specific intensity stated above for all interesting analytical y-lines is cal­ culated from the comparator spectrum according to a special program. The correctness of the specific intensities of the analytical y -lines is controlled on the base of GS-spectra. Then the spectra of the analyzed samples are measured and the concentrations of all interesting elements are calcula­ ted with the help of improved program [2],

The universal comparator method stated above significantly simplifies the known procedures for determination of re­ lative efficiencies of the registration of analytical lines of interesting radionuclides so reducing a labor- and time investments for making analysis; this is very important in the case of a large scale NAA.

[1] Patent USSR N 1116341. [2] Smakhtin, L.A., et al., J. Radioanal. Chem., 2 (1980) 423-432.

206 THE DETERMINATION OP RARE-EARTH ELEMENTS IN ENVIRONMENTAL OBJECTS

Smakhtin L.A., Mekhryusheva L.I., Pilippova N.V., Miglina N.V., Sinitsyna T.S. Karpov Institute of Physical Chemistry Section Obninsk, USSR

In many natural objects one can determine 8-9 rare-earth elements (REE) by high efficient INNA. Por the determinati­ on of the greatest part (11-12) or all REE the destructive variants of NAA (DNAA) with radiochemical or pre-separation of REE sum may be applied. The most published works on DNAA cannot be used for high efficient analysis.

The aim of the work was to develop the effective method of neutron activation determination of REE in natural objects with pre-separation of the concentrate of these elements.

Different variants of separation of REE sum were studied: coprecipitation as oxalates on the formed calcium oxalate precipitate, sorption on polymeric chelate sorbent, copre­ cipitation and extraction as thiooxinates or 8-oxyquinoli- nates, variants of extraction-chromotographic separation of REE sum [1-3]•

A final variant of pre-separation and concentration of REE for the next activation determination was following: after successive treating the sample with HNO- (cone.) and mixtu­ re HP-HpSO. (for elimination of silica) the solution was ne­ utralized and passed through the column at pH=2, The column was charged with porous teflon on which the solution of die- thylhexilphosporic acid in toluol (1:5) was applied, REE , iron, scandium, uranium etc. are sorbed on teflon. Alkaline

207 and alkaline-earth elements pass trough the co­ lumn. In elution of 0.1 N HNOo the most amounts of chromate cobalt, titanium etc..are removed. REE sum was eluted with

7 N HN03.

Iron, scandium and uranium remain on the column. Extraction (coprecipitation) of REE sum as thioxinates was used for de­ creasing the volume of REE concentrate and removing Na, con­ taining in eluting solutions. The chemical yield was cont­ rolled with the help of carries-free isotopic tracers ("°Ce, * Pm). REE concentrate obtained was analyzed by INAA.

The detection limits of REE are n(10"^-10~11)g, Sr=0.10-0.3.

The productivity of the procedure is 500 element-determina­ tions per a month for 2 performers.

This method was applied for analyzing geological samples, underground and surface waters, some technological materi­ als.

[1] Patent N 1057799, USSR. [2] Veveris, O.E., Vircavs, M.V., Kalninya, Z.B., Izv. A.S. Latv. SSR, ser. chira. (1979) 426. [3] G0ST 23862, t-79.

208 COMPLEX OF PHYSICAL METHODS OF ANALYSIS 20 INVESTIGATE 3LLSIMDAL COMPOSITION OF NATURAL HYDROCARBONS V.P.Solodukhin Institute of Nuclear Physics, Academy of Sciences of KazSSR

The report presents original methodical developments based on different variants of activation, X-ray fluorescent and atom-emission methods of analysis to study composition of oil, oil shales, oil-bituminous rocks and their various fractions* The techniques in whole give possibility to determine from 15 to 30 elements in oils, bitumens and organic fractions of caustobioliths and also from 15 to 40 elements in oil shales, oil-bituminous rocks and mineral fractions of caustobioliths. In many high tough oils from different deposits of our country high content of vanadium, nickel, sulphur and in some of them molybdenum, bromine, arsenic has been found. Oil shales and oil-bituminous rocks contain selenium, argentum, antimony, chromium, titanium and other valuable impurities except of the elements mentioned. The analytical data are used to solve several scientific and practical problems in the fields of oil geology and commercial processing of natural hydrocarbons. The perspectives of development of methodical investigations for elemental analysis of organic fossils are considered.

209 AN AUTOMATED SYSTEM FOR IMA Song Quanxun ( Chinese Institute of Atomic Energy, Beijing )

The paper describes an automated system at HVBR of CIAE for IKAA. The frame figure of the system is as follows:

i . / A' >k y ,r 1 2 3 4 5 1 ; >k * ^v >'\ ho 't 7 . t t *~ 7 <. 1 "I t i 7 t » y 10 •

2 or 3 | L t " —? 5 11 -: S 12 / 13 e— 14 15

Frame figure of the automated system for INAA 1-automated sample changer; 2-Ge(iA) detector, .3-BF3 detec- , tor;4-delay port; 5-HWER; 6-LV-power; 7-display.and control- .ler; 8-HV-power; 9-storage chamber for actived samples; 10- compressed air source; 11-preamplifier; 12-amplifier; 13-S- 85 MCA{ 14-IBM-PC computer; 15-2024 printer.

The applications of the automated system are as follows; 1. Determination of the uranium contents by DNC The change and irradiation of sample, collection, transfer and treatment of data and so on are all automatically per­ formed. When any accident occurs, the measurement is auto­ matically stopped. The detection limits for natural uranium are about 0.01 ppm and 0.7 ppb for single irradiation and 20

210 times cyclic activations, respectively. 2. Automated multielement INAA with short-lived nuclides The weight of the sample is about one gram, the irradiation time is ten to twenty seconds, the delay time is twenty to thirty minutes. It can automatically determine Na, CI, Mg, Al, Ti, V, Ma, Dy, Sr, Ca, and so on. 3•Automatic determination of middle-lived nuclides The sample irradiation time is 60 to 90 seconds. After irra­ diation the activated samples are stored in a circle poly­ ethylene tube to decay for 2 to 4 days. Before measurement of these samples the circle polyethylene tube is connected to the delay port, the sample is sent from the port to Ge(Li) detector. It can automatically determine Sc, Cr, Ga, Fe, Co, Zn, Hb, Sb, Csi La, Ce, Sm, Eu, Yb, Lu, W, Th, Ba, Br, As... elements. 4. Automatic determination of long-lived nuclides The active samples are put in the magazine of the automated sample changer. The sample is directly sent to the Oe(Li) detector, in this case the device is an automatic y spectro­ meter.

(1) Minor, M. M. et., J. Radio. Chem., 70, 459 (1982) (2) Song Quanxun, Atomic Energy Science and Technology, Vol. 20, (4), 485 (1986); vol. 21, (3), 259 (1987) (3) Song Quanxun, Nuclear Techniques, (1), 21 (1985); (10), 35 (1987); (9), 42 (1987) (4) Song Quanxun, China Nuclear Science & Technology Report, CNIC-00236, IAE-0048, (1988)

211 y NEUTRON ACTIVATION ANALYSIS OF CONSTITUENT MINERAL ELE­ MENTS CONTENT OF FEEDS AND BIOLOGICAL SAMPLES.

Stefania Spiridon -Central Institute of Physics,Bucharest R-76900,P.O.Box MG-6,Romania Gheorghe Spiridon -Institute of Biologie and Animal Nutrition -Balotesti,Romania

Introduction-The increasing significance of essential mine­ ral elements in animal nutrition has required the accurate determination of their content in the feeds included in a- nimal diets.For the determination of very small concentra­ tions of these elements in feeds and biological samples, precise,accurate and very sensitive analytical methods,like neutron activation analysis should be used (1)»The present paper is based on the utilisation! of this method of analy­ sis for the determination of the concentration of the fol­ lowing elements: Ca,Co,Cr,Cs,Fe,K,Mn,Na,Sc,Zn. Experimental-Samples of corn,wheat,barley,alfalfa hay,green alfalfa,feathers and long bones from various areas were col­ lected. The samples were dried at 60 6C for 48 h,weighted in polyethylene bags and irradiated in special vials.As stan­ dards, fly coal ash ENO and G-2 were used.All samples and standards were irradiated at thermal neutron fluxes of 1,1. lO^n.cm-^.s"1 and of 3.1012n.cm"2.s""1 for l±0 to 50 h and for 1 to 5 min resp,in the VVR-S reactor of CIPh-Bucharest. Gamma ray measurments were carried .out with a Ge(Li) de­ tector which was connected with a 4096 channel analyzer. Results and discussions-The concentrations of constituent mineral elements in the feeds and biological samples analy­ sed are given in Table 1,In some samples, the element concen­ tration was carried out by calcination at 450 pC.The results in Table 2 show that losses of some of the contents of the-

212 se elements may occur* Conclusion- Although not sufficiently rapid,especially for heavy element determinations (Co,Fe,Zn),at present the ne­ utron activation analysis is useful for getting data on the concentrations of constituent mineral elements contai­ ned in feeds and biological samples,By employing this in­ strumental method,contamination and chemical reagent utili­ sation are avoided and also may eliminate sample calcinati­ on sometimes used in classical chemical analysis* Table 1, Constituent mineral elements contents of some fe­ eds and biological samples,dried at 60 °C.

Ele- Corn Wheat Barley Alfal- Green Feathers Long ment fa hay alfalfa bone Ca ppm _-___-. 268,3 Co ppm 0,102 0,166 0,292 0,212 0.163 37,kO Cr ppm 0,018 - 4,38 Cs ppm 0,46 - 51,20 1,75 Fe ppm 81,80 383,0 845,2 1461,5 728,5 47,50 K % 452,0 573.0 186,2 1489,0 859,6 13,60 0,54 Mn ppm 7,83 33,5 19,3 26,1 14,4 0,70 0,025 ' Na % 2,46 399,0 137,1 47,73 510,0 10,84 2,64 Sc ppm 0,084 0,121 0,82 0,20 0,4 Zn ppm 0,64 42,1 121,0 59,80 61,8 138,60 9,2

Table 2«Constituent mineral elements contents of some feeds calcinated at 450 °C.

Element Corn Alfalfa hay Green alfalfa Co ppm 0,053 Fe ppm 38,25 543,9 383,9 K % 384,49 1430,0 525,4 Na % 115,00 - 35,78 Zn ppm 0,49 40,5 28,4 Bibliography-I.Stefania Spiridon,G.Spiridon,9-th Annual Con­ ference "Progress in Fizica" of Central Institute of Phys­ ics-Bucharest, Romania, October. 1987.

213- INVESTIGATION ON BACKGROUND VALUES OF TRACE ELE­ MENTS IN SOILS OF CHINA WITH INAA. I. THE BACKGROUND VALUES OF U, Th AND REE IN SOIL

Sun Jingxin and Wang Yuqi Institute of High Energy Physics, Academia Sinica P.O.Box 2732, Beijing, 100080, China

The soil is one of the essential factors in ecological environmental system which include air, water, soil, organisms etc. and serves as an important medium for the accumulation, transformation and migration of various nutrient and toxic sub­ stances in the system. Therefore, the study on natural background contents of trace elements in soil is of vital importance in environmental and biological sciences as well as pedogeochemistry. It can provide most basic data for the assessment of environmental quality, the evaluation of the extent of environmental pollution and for applying the fertilizer of trace elements scientifically.

During .(the last decade, the investigation of background values of trace elements in soils of China has been widely carried out by instrumental neutron activa­ tion analysis (INAA) in our laboratory. Total of 364 soil samples were collected uOm some typical areas in China. These areas cover as follows: Guangzhou and Hainan(G.H.), the Xiangjiang Valley of Hunan Prov.(X.V.), the Songliao Plain area(S.P.), Tianjing(T.J.), the North Xinjiang(X.J.) and the Mt. Qomolangma region(Mt.Q.),respectively.

The raw soils obtained were prepared by drying, spilitting, grinding and homoge­ nizing before analyzing. The contents of 26 elements in top soils were determined by INAA. Irradiation of the samples and the standards of elements were performed in the reactors at the Institute of Atomic Energy or the Qinghua University with an integral neutron flux 5<10 -1«10 n/cral Induced radioactivity measurement was carried out by a SCORPIO-3000 gamma spectrometer with large volume Ge(Li) and HPGe detectors coupled to a microcomputer.

In this paper, the background values of U, Th and 8 rare earth elements(REE) in soil were reported (see Table 1). The distribution characteristics of elements in different great group of soils and the soils derived from different parent materials were also discussed. The other elements will be published elsewhere.

214 Table 1. The Background values of U, Th and REEs in Soils

(PPM) G.H. X.V. S.P. T.J. N.X. Mt.Q. World's Element N=18 N=96 N=96 N=36 N=104 N=14 soil[l] La 44.2 39.7 34.4 35.1 30.0 30.5 40 Ce 99.7 92.5 70.7 74.1 57.6 67.2 50 Nd 53.0 30.3 35.1 32.5 28.6 31.7 35 Sm 6.35 5.95 5.90 6.21 5.79 5.39 4.5 Eu 1.26 '1.11 1.17 1.28 1.18 0.78 1 Tb 0.89 0.81 0.77 0.74 0.81 0.66 0.7 Yb 3.42 2.80 2.52 2.34 2.76 2.09 3.0 Lu 0.42 0.47 0.42 0.47 0.43 0.37 0.4 U 5.97 4.20 2.34 1.77 2.71 4.88 2.0 Th 37.0 17.0 10.8 12.1 10.0 15.7 9.0

Reference

[1] Bowen, H.J.M., Environmental Chemistry of the Elements, p.59, Academic Press, 1979.

215 DETERMINATION & EVALUATION OF TOXIC AND TRACE ELEMENTS IN CHINESE FOODSTUFFS

Sun Laiyan, Lu Fengying, Su Rangwei, Zhen JUQUXL Institute for Application of Atomic Energy, CAAS P. 0. Box 5109, Beijing 100094, China

The toxic and trace elements As, Br, Cd, Or, Cu, Hg, 5b, Se and Zn in Chinese foodstuffs in Beijing, Wuhan, Xian, Shanghai and Chengdu were determined. More than 100 food samples in each city were collected from different local markets. They include various main foodstuffs, such as, rice, wheat flour, corn flour, cabbage, Chinese cabbage, tomato, potato, sweet potato, apple, pear, banana, milk, orange,"egg, pork, beef, lamb, chicken, fishes and so on.

Sampling and sample preparation were done in accordance with the IAEA recommendation U). Instrumental and radio­ chemical neutron activation analysis techniques were used and improved for determining those element concentrations in foodstuffs. I'he used methods have good sensitivity, accuracy and precision, and have been checked by analysing standard reference materials BBS Rice Flour, Citrus Leaves and Bovine Liver, and by the Analytical Quality Control Exercises for the IAEA CRP on Nuclear Analytical Techniques for the Toxic Elements in Foodstuffs.

The measured results show that almost all of the toxic element concentrations in the samples collected from five cities did not exceed or approach the maximum permissible levels specified in our national legislation or interna­ tional guidelines 12). A few samples had higher Cd or Cr

216 contents. We are trying to find the reason.

The information on the daily intake of toxic and trace ele­ ments for population groups concerned was provided. The average element daily intake of one person was listed in Table 1. It was calculated according to the person's aver­ age dietary intake (except drinking water and air) (3) and the mean values determined for each kind of food. All the toxic element data are within the safety ranges.

This study was supported by the IAEA. Further investiga­ tions are still doing.

Table 1 Average Daily Element Intake A Person tin ftg)

City As Br Cd Cr Cu Hg Sb Se '6n Bei jing **2.6 11*45 38.2 166 1738 5.2 832 107 7939 Shanghai 52.2 519 36.8 167 1213 6.^ 6/18 91.5 6028 Xian i*6.2 1132 40.0 184 1782 5.0 978 119 8729 Wuhan 63-2 528 39.k 1^2 1556 5.8 6^0 76.9 7882 Chengdu 58.9 1087 if2.8 177 1699 5.6 684 120 9301

U) Parr, R.M., Technical Considerations for Sampling and Preparation of biomedical samples for Trace Element Analysis, J. Research of N.B.S., 91 (2), 1986. (2) Reilly, C, Metal Contamination of Food, Applied Science Publishers, London U980). (3) Nutrition and Food Hygiene, CAPM, Compilation of Nutri­ tion Materials Investigated in 1982 (1985) pp.58 - 59.

217 POSSIBILITIES OF APPLICABILITY OF PROMPT ACTIVATION TECHNIQUE IN THE FOOD CHEMISTRY

A.S. Szabo University of Horticulture and Food Industry Chemistry Institute Department of Food Chemistry and Nutrition Science 1118 Budapest, Somloi street 1if-l6 HTWIGARY

It is wellknown that the knowledge about the elemental composition of different food samples is of great im­ portance in consequence of the development of nutrition science /e.g. essential and stimulative trace elements/ and of the environmental contamination /toxic elements/ The investigation of the food samples requires rather sensitive and rapid analytical methods, like INAA or XRF. In the lecture some information are given about the classification of the different methods of AA and the trends in the prompt activation technique, concerning the food analysis(l}» More detailed information are reported about the boron and strontium determination of food /biological/ samples* Boron is one of the most important trace elements for plants, and to the research, carried out in the last years it is possible that boron is - in very small con­ centration - essential also for animals and human be­ ings £2j» The basis of the boron determination is the following prompt nuclear reaction: 10B/n,

2i8 In consequence of the very high cross section/^3800 barn/the method is sensitive even in thecase of relati­ ve small thermal neutron flux. There are 3 possibilities of nondestructive boron determination using this reacti­ on (3 J.: - detection of the prompt o(-particles with surface bar­ rier silicon detector in vacuum chamber - detection of the prompt c< -particles with SSTD, using the /n,

219 ISOTQF'ICALLY ANOMALOUS MERCURY IN METEORITES BY NEUTRON ACTIVATION ANALYSIS; A COSMOCHEMICAL APPLICATION

A. N. Thakur Department of Chemistry, Indian Institute of Technology, Kanpur 208 016, INDIA

The meteoritic high abundances of Hg and the variable 196 202 Hg/ Hg ratio have remained unsolved puzzles in cosmo- chemistry for almost two decades [1]. In this paper we address to the problem of existence of isotopic anomaly in Hg in some meteorites and show that these are real and need to be explained in terms of the presence of extrasolar material in meteorites. 196 202 Hg and Hg isotopes have been measured by neutron activation analysis in samples of stone meteorites and acid insoluble residues of iron meteorites (AjtRIMS) - Hg is extracted from an irradiated (10 13 n cm -2s -- 1 ) sample by stepped heating under vacuum and counted over HPGe detector.- We measure the photons of 77.3 keV gamma rays plus 77.9 keV x-rays from Hg(197) and of 279.2 keV gamma rays from Hg(203). Decay corrections for the two radio nuclides have been applied in tabulating the data. The abundances of mercury are calculated on the basis of Hg(202). Stone meteorites have mercury concentrations ranging between 0.07 to 33 ppm. Bulk iron meteorites have 0.05 to ~34.7 ppm. AIRIMS, having Hg contents ranging from 0.02 to 680 ppm, clearly show a many-fold enrichment in Hg. 196 202 While many samples give Hg/ Hg ratios within 10 % of normal, in some cases large discrepancies are observed. Often in the same residue, both positive and negative devi­ ations are found at different temperatures. Some of the typical values are given in Table 1. All the results are spectrum analysed. A thorough scrutiny of various steps involved in the experiments has been carried out to ensure that the observed abnormal activity ratios are not due to experimental artifacts which might have arisen either during irradiation or during the subsequent radiochemical purification and counting stages. Several control experi­ ments show the variations are not due to (1) modification of neutron energy spectrum within a normal packing, (2) variation in counting geometry/rate, (3) the presence of peaks near any of the gamma lines due to contamination, (4) the presence of neutron absorbers like Cd and B in the meteorite matrix and (5) a drift in the instrument gain.

220 TABLE 1. Some typical values of Hg isotopic ratios in meteoritic samples

Mass Temp("C) 196., ,202„ Sample (mg) ranges ppm Hg/ Hg IRONS: Bogou 1042 RT-100 0.03 1.38(10) 100-200 0.07 1.46(12) Canyon- 4279 RT-100 0.06 0.73(18) Diablo 200-300 0.03 1.27(15) AIRIHS: Campo- 66 RT-100 2.35 1.26(5) del Cielo 100-200 5.54 0.93(2) 200-300 0.60 1.00(3) 300-400 0.56 1.15(4) Sikhote Aliin 75 200-250 11.00 <0.01(2

[1] Reed, G. W. and S. Jovanovic, J. Inorg. Nucl. Chem. 31 (1969) 3783-3788. [2] Thakur, A. N. and P. S. Goel, to appear in Earth Planet Sci. Lett. (1989).. [3] Nier, A. O. and D. J. Schlutter, J. Geophys. Res. 91 (1986) E124-E128.

221 STUDY ON THE DISTRIBUTION OF SELENIUM AND OTHER ELEMENTS BY NAA AND BIOCHEMICAL TECHNIQUE

Tian Jibing, Qian Qingfang, Chai Chifang Institute of High Energy Physics.Academia Sinica.P.O.BOX 2732,Beijing,China

Three kinds of proteins(albumin,globulin and gliadin) in corn samples from high selenium area and normal area were separated.The contents of Se and other elements in these proteins were determined by neutron activation analysis (NAA).

1.Globulin In the normal area,the enrichment coefficients of Se.Cu.Cl and V in the corn globulin are 94,16,4 and 2.respectively.In the high selenium area,they are 9,45,2 and 2.respectively.

2.Albumin In the normal area, the enrichment coefficients of Al, Cu, Mn, CI and V in the corn albumin are 3, 8, 2, 8 and 6,respectively.Se exhibits a little enrichment. In the high selenium area, the enrichment coefficients of Sef Cu, Mn,Cl and V in the corn albumin are 4.6, 10, 3,7 and 2,respective -ly.Al has a little enrichment.

3.Gliadin In the normal area,the enrichment coefficient of CI in gliadin of corn is 2. Se has a little enrichment. Al.Cu and Mn show a little deficiency.In the high selenium area,the enrichment coefficients of A1.C1 and V in gliadin of corn are 4,4 and 4,respectively.

4.Selenium is an essential element in human body.The results show that the selenium content in corn proteins from the high selenium area is higher than that from the normal area.

222 Table 1 The elemental contents in corn proteins from high selenium and normal areas(ppm)

Sample 1 element in high in normal area No. | selenium area

globulin corn globulin corn (32.21mg)* (95mg)** (37.76mg) (129mg)

1 Se 102.7 11.5 4.05 0.043 1 | Al 41.2 22.8 39.7 32.1 I Cu 76.9 1.7 50.7 3.06 1 ci 744.2 459.1 1472.1 394 1 Mn 3.22 4.78 3.57 7.59 1 V 0.06 0.027 0.087 0.038

albumin I albumin corn (35.05mg)| (14.12mg) (H5mg)

I Se 52.6 11.5 0.739 2 | Al 34.9 22.8 82.0 27.3 1 Cu 16.3 1.7 24.1 3.05 I Mn 14.4 4.78 9.50 4.39 1 ci 3183.0 459.1 2877.1 374.8 1 V 0.078 0.027 0.210 0.033

gliadin I gliadin corn (28.43mg)| (97mg) (120mg)

I Se 17.9 11.9 0.48 0.39 3 | Al 1 83.0 22.0 23.2 29.7 I Cu <18.0 2.45 <0.6 3.05 1 ci 11450 372 877.0 384 I Mn 1 4.49 5.14 I 3.18 5.99 1 V I 0.13 0.042 I 0.022 0.036

Note: *the weight of protein sample extracted from lOg corn. **corn sample weight.

223 FIG.l. The biochemical separation scheme of corn protein

corn I

add 20ml I stir 1 hour (Step 1) deionized water! centrifuglized

I I

Iprecipitatel I solution I

repeat Stepl I

I- Iprecipitatel I solution I

add 20ml I stir 1 hour | (Step2) 0.5H NaCl,I.centrifuglizedI - repeat step2l

| I | solution | (Step3) I Iprecipitatel I solution | dialysis 148 hour with | add 20m. 70\/Jalcohol | dialysis |48 hour polyglycol stir 1 hour, | with deionized water centrifuglized centrifuglized | .centrifuglized | repeat Step3 | | I solution

I solution freeze Iprecipitatel -dried I solution I Ifreeze I-dried dialysis 48 hour | I with deionized water .centrifuglized I

I solution

freeze I -dried I I

Igliadin | | gliadin I I globulin albumin land oil | | | I

224 A STUDY ON ELEMENTAL PEDOGEOCHEMISTRY OF LOESS PLATEAU, CHINA, BY INAA

Tian Junliajig, Liu Puling, Li Yaqi Northwestern Institute of Soil and Water Conservation, Academia Sinica Yangling, Shaanxi, China

Because of the unique advantages, such as sensitivity, selectivity, and multielemeiital cabilities, NAA has been used to studies on a wide variety of disciplines. Tliis paper exhibits a distinctive application of INAA on geochemistry of soils on the Loess Plateau. China.

The preliminary results in our study have shown the application is satisfactory. It not only simutaneously reveals the concentrations and distributions of elements in soils derived from loess, but also provides accurate abundances of some stable elements (e. & Hf) as ideal reference bases to estimate the trace element transportation and accumulation during the soil formation. Furthermore, it is economical with lower unit cost compared to other chemically analytical methods in China.

It is the first time to make a systematic study on elemental pedogeochemistry of the plateau. More than 40 elements of 400 soil samples have been analysed, 33 elements among them are respectively determined on a Ge( Li) and a HPGe detector by INAA, witli the both short and long irradiations in a nuclear reactor. A proper analysis procedure including optimum cooling and measuring periods as well as corrections needed has been developed for routine analyses of the soils. To inspect influence from the complex matrix and to ensure the analyses reliable results, GSS-S. a loess standard reference material prepared by Institute of Geophysical and Geochemical Exploration (IGGE), China, is elected as the secondary standard irradiated and determined with the first standard NBS 1633a in each batch of samples. The GSS^ data for most elements obtained in our study have a good agreement with the usable values given by IGGE. It also shows that either hornogenity or date accuracy is good enough to make GSS-8 a satisfactory SRM, especially for multielement analyses of soils developed from loess. *Our paper presents a discussion about GSS^S in details.

The plateau covers almost 500 thousand square kilometers in China. Because loess

225- as soil parent materials has a cornpositionally similar source, some regional differences of trace elements in soils from loess can not b« clearly demonstrated unless the analytical methods employed are precise enough. Statistical analyses of our data show significant variation among the three typies of loess ( sandy loess, loess, and clay loess) as well as layers in the same soil profile. Therefore, a set of reliable data by IN A A may be used for regionalization of pedogeochemistry on the plateau. By using Q-model cluster analysis of the data, a example of the regionalization for part of the plateau is presented in the paper. It confirms the expectation that regionalization has a satisfactory agreement with the field surveys of soil zones depending on varied environments. This reflects the fact that the soil gtsochemicai characteristics are strongly effected by the process ,of soil formation and bio-climatic environment in which the soils are generated.

226 Further Study on Parameterization of Reactor NAA

Tian Wei-Zhi Ni Bang-Fa Chinese Institute of Atomic Energy, Beijing

The completion of ko compilation for 112 (n, y ) reactions of NAA interest has made it possible to determine more than 60 elements parametrically . In present work, some of the remaining aspects are studied in an effort to achieve all-round parameterization of reactor NAA.

l.ko standardization for non-l/v nuclides As discussed by De Corte et al., non-l/v effect should be considered for 13 nuclides when k0 method is to be used. In practice, the most important ones are 151Eu(n, y ),52Eu, ,78Lu(n, Y ) l77Lu and 191Ir( n, y ),92Ir. "Working V values have been determined and used for these three reactions in typical irradiation channels of our Heavy Water Research Reactor(HWRR). The neutron temperature has been estimated from the " working k„" and g (T„) of ,76Lu(n, y )mLu for typical rock and soil samples C ~ 200 mg sample in our standard Al can, t,= 6—8h).

2.Parametric corrections for fission interferences A neutron spectrum-independent "compound nuclear constant" , Hennas been proposed for fission interference corrections by parametric method . K f+ QS •" M*. Y, Ik- (exp.)= 0.017625 (theory) K f+0.472Y>Y, H*. a1

K f + 0.472 Y,/Y,

. AJ, £+Q5 Iko values for eight majior fission interference cases, have been determined in six irradiation positions (with <3>th/e 13.7—134 )- The general agreement among experimental Ik0 ' s

227. trom different irradiation positions and between experimental ind calculated IkQ values for the same interference case verifies the validity of the method.

3.Parametric corrections for y spectral interferences

Ik0 concept descrihed above has been used for y spectral interferences. The interference factor Ap/A* can be calculated as f + Qfl S • D • C

Ap/Ap= Iky • • f + QS Sl • D' • C*

4.Parametric corrections for threshold reaction interferences The following equations are deduced for parametric corrections for threshold reaction interferences induced by reactor fast neutrons,

A., Oth QJ H .81* aQ y IV (1 + Xexp.)= (-X theory) 1 1 k% 3>f f H M a* Y A3P S>th 1 = Iko : A;P &, i + QflVf

5.Parametric normalization for detection efficiencies at "far counting positions Effective Interaction Depth ( EID) principle has been successfully used for normalizations of detection efficiencies in different counting positions with true coincidence effect negligible.

6.Parametric corrections for true coincidence effect In parametric corrections for summing effects, it is emphasized that the area under real total spectrum, instead of an extrapolation from the Compton plateau region back to zero energy, should be used as total response in the calculation of total efficiencies. A NAA computer program CCC including all the above features has been successfully used for 1.5 years in our laboratory.

228 A STUDY ON SAMPLING REPRESENTATIVENESS OF IAEA RM SD-M-2 TM MARINE SEDIMENT BY 1NAA

Tian Weizhi, Peng Lixin Institute of Atomic Energy P.O.Box 275 (50),Beijing, China

Homogeneity is one of Ihe most important properties of SRMs.Many workers have routinely utilized statistical tests ( i.e. F-tests) and the degree of inhomogeneity (Siuli). [l] for homogeneity testing of SRMs .But these tests can not give a true picture of sampling representativeness for a constituent , especially a trace element in a given material.

Ingamells [2] proposed a sampling constant Ks for well-mixed material . k's ran he determined from the relationship Ks=R\« (3) Where R is the relative sampling uncertainty determined from the analysis of a set of subsamples of weight w .INAA has recently been used for Ks determinations of multielements in some materials [3, i, 5]. However, no confirmation was given as for whether the materiats under investigations are "well-mixed " ,which is a prerequisite of Ks theory .

Visman [8] suggested two constants A and B S.'-A/nw + B-'ii (2) A and B can be calculated from the following equations l A-«„w„(Su - S,.V(Wlt-VO (3) B=SJ -A/w„ (or S,,' - A/w,.) (4)

Where A is a homogeneity constant , B is a segregation constant , Sa' is the

sampling variance for a set of small-sub samples, Slt' is that for a set of large-subsamples , w„ is the small-subsample weight , and w„ is the. largc-subsample weight .

i. 229 Based on Visman's, theory , we have for the first time determined A and B constants .for 6 elements, as well as Ks for 16 elements in IAEA RM SD-H-2'TH Marine Sediment by INAA .

In evaluation of the sampling constants Ks ,A and B ,we considered that (1) The sampling constants (Ks ,A and B ) are meaningful only when the sampling l , , variance is discernible in the overall variance.(V -B1=V wl.+V MrtlM ). (2) If S',w„ > S'jv,, and S*„ > S',, , the sample is considered to be segregated and S„ and S„ can be used to estimate the values of A and B.

The following conclusions for IAEA RM IAEA-155 SD-M-2/TM Marine Sediment can be' drawn from the present study , (l)The sampling constant Ks varied greatly with elements from 2 mg ( for Cs ) to 4000 rag ( for Tb ) . (2)Some elements such as Cr ,Th and REE were found to be segregated obviously . (3)Ingamells' constant Ks' equals to Visman's constant A , when B equals zero (for well-mixed materials ) ; B stands for the degree of segregation . (4)The sampling variance for a given element in a material can be estimated for any subsample weight w from the equation (2) when values A and B are known for this element .

[1] G.Guzzi, A.Colombo,F.Girardi, R.Pietra, G.Rossi,N.Toussaint, J.Radioanal.Chea., 39 (1977)263-276. [2] CO. Ingamells,P.Switer,Talanta 20 (1973)547-568. [3] Byron Kratochvil, M.John M.Duke , Dennis Ng,Anal. Chem., 58 (198&) 102-108 . [4] R.H.Filby,S.Nguyen,S.CampbeI,A.Bragg, C.A.Grimm, J.Radioanal.Nucl.Chem., 110 (1987)147-158 . [5] K.Heydorn,E.Damsgaard, J.Radioanal.Nucl.Chem., HO (1987) 539-553 . [6] J.Visman, Mater.Res.Stand., 9 (1969) 9-64 .

230 TRACE ELEMENTS IN THE HUMAN EYE TISSUE

TluChor D., Stverak B. - Institute for Research, Production and Application of Radioisotopes, Prague Ciganek L. - Central Millitary Infirmary, Prague

The instrumental neutron activation analysis method has been used for the determination of trace elements in various human eye tissues. The finding of the relation between the deposition of some elements in transparent or cataracted human eye was the main aim of this work. An attention has also been paid to the influence of the age, sex, profession, health conditions and locality of the donors. The three types of the groups of samples have been analysed: 1. turbid eye lenses after the operating of eye cataract-, 2. different types of eye tissues ( cornea, iris, lens and vitreous humour ) of the donors from the polluted industrial Prague region and 3. the same types of donors tissues from the nonindustrial part of Bohemia. The samples of donors hair have been analysed altogether with samples of eye tissues to found the trace element exposition of the individual donors. Simultaneously with all samples the reference materials of IAEA were analysed. The results of corelation statistical tests between the trace element contents and life parameters of donors show to the dominant influence of lokality, which probably super­ imposes the effects of other parameters. Expressive higher contents of elements was determined in iris. The lower con­ tamination of all trace elements was found in female popu­ lation. The lower ratio of Na/K contents was found in effected tissues (cataracted lenses). It indicates the disorder of the nourishment of mechanism of tissue cells.

231 A NEW METHOD FOR CLASSIFYING PARENT TYPE OF ROCKS CONTAINING DISSOLVED ORGANIC MATTERS

Tong Chunhan, Li Guodong Institute of Applied Nuclear Technique, Chengdu College of Geology Chengdu, Sichuan 610059, China

When estimating oil—gas fields, petrogeologists are interesting in organic parent type of produced oil—gas,because it has much to do with both quality and the quantity of the oil—gas. Organic matters are divided generally into two types,i.e.,rotten slime type and humus type.The organic matter of rotten slime is the matter with rich content of fat and the like formed in the condition of insufficient oxygen, such as sedimentary, dissociative and combinative product of hydrobionic algse at marine facies and lake facies,with oil as main product.The latter has been formed evolutioharily from terrestrial plants in the condition of oxygen presence,with gas as main product.

In practical work the organic type is usually presented by the type of its major parts (above 90%) kerogen. Type I presents rotten slime;type III,humus;and type n,hybrid.The conventional methods of type classification mainly depends on C,H,0,parts of kerogen and other auxiliary method.

Because the effect of maturation (temperature rising and pressure increasing) made indistinct the differences of the organic raw parts of different types,particularly high maturation making all kerogen C, H, O parts to be identical, the organic type will be dificult to be determined/Therefore new method are to be tried in order to resolve this difficulty. This paper describes such a new method—neutron activation anslysis which features high sensitivity,little weight of samples and multielement analysis and consequently can be used to measure trace metal elements in dissolved organic matter so as to distinguish the organic type.

232 Chloroform petrolene A have been prepared out of the samples from the field of the Northeast of China, some of the INAA result of the samples are shown in Tab l.The data show that V,

Tab 1. The result of INAA of trace elements in organic of the rocks.

Chloroform—petrolene A Petrolene D3 D5 D8 Gl G2 G3 V 0.21 0.21 8.1 2.8 7.2 6.4 Ni 5.4 8.8 165 20 100 75 Cr 1.2 2.8 3.3 6.6 9.8 4.1 Type in n n m n n Ni content difference raises distinguishability in parent type classification. Type II has more content by 30-40 times than type EI for chlorlform—petrolene A; and by 3—5 times for petrolene samples. Such regularity has been found in over 30 samples. Hence, this method is efficient for organic parent type classification in condition of high maturation.

233 NEUTRON ACTIVATION STUDIES ON THE GEOGAS FROM A HIDDEN GOLDEN ORE DEPOSIT

Tong Chunhan, Liang Xingzhong, Li Guodong, Li Juchu Institute of Applied Nuclear Technique Chengdu College of Geology Chengdu, Sichuan, 610059, China

Underground water contains gas bubbles. When flowing through an ore deposit, the bubbles will react with the ore , then move upward to the ground together with many trace elements, and therefore produce very weak anormalies of some marker elements related with the mineralization. Using a purpose-made detector and the neutron activation analysis to capture the elements in the geogas and determine their concentrations, one can deduce whether there is a hidden ore deposit or not in the deep. In this study, Jiaojia golden ore deposit was researched by the geogas method. The deposit, with the large scale orebody and being in hidden or half—hidden state, was formed by the hydrothermal alteration of the shattered rocks in the faulted structure. The roof rocks were shattered,so the passages of the geogas were good. A total of 15 elements,As, Sb, Br, CI, Au, V, Cr, Sc, U, Na, K, La, Sm, Ti and Al, which amounts captured on the detector were higher than the detection limits of the neutron activation analysis, were detected. In these elements , Cr, U, Br, As and Sb, which enhancement factors are as great as 6 - 50, are fine characteristic elements in the geogas. The factors of La, Sm, Sc, Na and K approached to 1 , that is, the concentrations of these elements on the detector are equal to that in the soil approximately, therefore the elements reflect the feature of the geochemical haloes in the rock or soil. It is discovered that the golden orebody burried 70 - 320m could form obvious anormalies of Br,

234 As, Sb, Cr and U, but the positions of the anormalies were shifted and the shifting distances are between 10 and 30m. The anormalies of La, Sm and Sc could be formed above the hidden golden orebody, but the concentrations of the elements in the geogas decrease to the background values with the increasing of the burried depth. It is concluded that the mineralizing salo can be divided from geochemical saloes by applying high sensitive multi—element informations from the geogas, and the detection depth is about hundreds meters. Thus the boring work can be arranged rationally and the great exploring expense can be cut down.

235 THE C0L2T0L' RANGE SIMULATION OF A SPECTROMETER RESPONSE FUNCTION FOR THE ESTIilATIOK OF ACTIVATIOII METROLOGICAL CHARACTERISTICS

A.V. Trukhov, A.P. Nauraov. and A.P. Ganzha Rostov State University, Research Institute of Physics, 344711 Rostov-on-Don, USSR

The simulation of the activation analysis process and its me- trological characteristics reduces substantially difficulties associated with the development of optimum activation techniques. The limits of detection, quantitative determination and analyti­ cal errors are the functions of the Corapton range of the spectro­ meter response function (SRF) /1/. The existing models of its calculation do not provide for sufficiently quick and accurate assessment of these metrological characteristics.

The present paper proposes a method for evaluating the Compton portion of the SRF which takes into account all processes of the single and double scattering of Y-quanta in the detector and construction materials of a spectrometer. The following expression

has been obtained /*/&)*£/%fajG)fi6<<>)+ y2(u!,£jv/7Ejet6o) +

where 11(E) is the number of registered pulses of amplitude E in the spectrometer; S is the photopeak area; 5j.j(cci,E) is the differential cross-section of the recoil electrons of energy E for the process of the Compton scattering of the energy quantum u> ; ^„(«,E) is. the differential cross-section of the back- scattering of the jf -quantum at construction materials of the spectrometer; ^ (E) is the relative registration effectiveness of the spectrometer; y~(o/,E) is the differential cross-section

236 of the double Compton scattering of the jf -quantum in the detec­ tor, <-J .(tOfE) is the differential cross-section of the ^f-quantum scattering process at construction materials of the spectrometer with the subsequent single scattering in the sensitive volume of the detector. The behavior of the functions

, *32 r is shown in Pig.1 (curves 1,2,3»4 and £'). Also shown is 22 the approximation made with their aid of the experimental Ha spectrum taken on the Ge (Li) detector. The coefficients U (ui), fl(u>), y(uj), € (£0) are determined by the design of the spect­ rometer and are functions of the energy <*> of the original )f- quantum. They have been found experimentally by the least-squares method for a given spectrometer from measurements of standard sources of ^f-quanta. Their quadratic dependence on u) has been ascertained. It has been shown that the proposed model of construction of the SRP guarantees the accuracy of evaluation of metrological characteristics sufficient for the purposes of activation analysis (error of -^ 7%). It permits the SRF to be described for semicon­ ductor and scintillation spectrometers with different screening against external irradiation and for a broad range of the energy CO (100 keV to 3 MeV).

'REFERENCE

1. A.P. Hauraov, S.I. Kafala and V.V. Turbin. Nucl. Instr. Meth. Ihys. Res., 18 B (1987) 272.

237 238 PRE-CON'CENTRATION METHOD USING AN ACTIVABLE YIELD TRACER FOR NEUTRON ACTIVATIOM ANALYSIS

>fasa^ichi^_Tsul\ada*, Daijiro Yamamoto*, Kazutoyo Endo, Hiromichi Nakahara *Department of Agricultural Chemistry, Faculty of Agriculture, Meiji University, Higashimita, Tama, Kawasaki 214, Japan Department of Chemistry, Faculty of Sience, Tokyo Metropolitan University, Fukasawa, Setagaya, Tokyo 158, Japan

Instrumental neutron activation analysis is one of the simplest and most widely used methods for the determination of multiple elements in variety of samples of various matrices. However, it is suited for determinations of many trace elements due to the simultaneous production of interfering radionuclides such as 2«Na which obstruct the y-ray spectrometry of less abundant nuclides. For the determination of those elements, selective chemical separations are required and they are applied either after neutron irradiation, often called radiochemical neutron activation analysis, or before neutron irradiation, pre- concentration method. The former method is commonly used, but it suffers from several disadvantages such as hazardous handling of a large amount of radioactivity, inadequancy for the determination' of short-lived nuclides and limitation in the amount of samples to be irradiated. The latter method is free from those problems and especially superior from the standpoint of radiological safety. However, it requires a careful treatment of the sample during the pre-concentration process to keep it from the external contamination and, also, aknowledge of the chemical yield in the chemical pre-concentration steps. This chemical yield is sometimes determined by an addition of an appropriate radioactive tracer whose handling, however, has to be carried out in a restricted radiologically controlled zone. In the present work, a use of an enriched stable isotope as an activable yield tracer in the pre-concentration steps is proposed. Many elements have more than two stable isotopes one of which is of little natural abundance. If such an isotope is highly enriched, it can be used as an activable yield tracer in the.pre-concentration steps. The method has been tested in this report by use of commercially available enriched ' '• s Cd and ' s 6 ny for standard reference matirials of loiown elemental contents. The natural abundances of those isotopes are 7.5 % and 0.057 %, and they can be tracers for the determination of Cd and lanthanoid elements, respectively. After confirming the accuracy and the detection limit of the method, it has applied to the determination of Cd and lanthanioids contents in various geological, environmental and biological samples. (1) Determination of Cd Biological SRM samples issued by'NIES were used to test the method. The enrichment of > '^Cd used was 97.13 %. A few grams of each sample were decomposed with mineral acids, and

239 purified by repeated extraction-back extraction steps with, dithizone- chloroform solution that contained masking reagents of KCN and sodium potassium tartrate. The sample solution purified for Cd was, then, dried on a piece of filter paper and wrapped with polyethylene film for neutron irradiation. Irradiations were carried out in the Triga Mark.II reactor of St. Paul's University and y-rays were measured by a 40 cm3 Ge(Li) detector connected to a 2K channel PIIA. The 116Cd(n,r)i i?Cd reaction was used for the determination of the chemical yield and i • *Cd(n,y)115«Cd reaction was used for the determination of the Cd content in the sample. Known amounts of the enriched isotope and of natural Cd were also irradiated as standards. From the two ratios of 11 7 Cd activity and ' '5«Cd activity produced in the sample and standard, the Cd content in question could be evaluated. (2) Determination of lanthanoid elements Biological and environmental SRM samples issued by NBS and NIES were used for the test. The enrichment of issjjy used was 21.59 %.. A few grames of a sample doped with •5 sDy were decomposed by acids or alkalines, and the lanthanoid were co-precipitated with iron hydroxide for neutron irradiation. After the irradiation, the lanthanoids were further purified from iron and other co-preciptated elements by an anion-exchange resin column. In the whole chemical steps, other lanthanoid elements were found to behave similarly to Dy. Those experiments have proved that the present method is extremely effective for both improving the detection limits and reducing our exposure to radiation in the determinations of trace elements in versatile samples. The present method can be applied to the determination of trace elements shown below ir. the periodic table.

PERIODIC TABLE Light Me tals Metaloids and I A 11 A VIII A

I 2 H Ho 1.M71 III A IV A VA VIA VIIA 4.00300

3 A 5 6 7 8 9 10 Nc U Be Heavy Metala B C N O F till III] 10.1! 12.011 10.0007 13.1114 11.1100 lo.in

11 13 13 14 15 16 17 18 VIII B. Ni Mr Al P s a Ar 27.W0 14.303 1MB IV B V B VI B VIIB I B II B 30.1113 70.010 10.1T3I 33.00 3S.4S3 31.H0 19 fc^!W 21 22 23 5 25 26 27 28 mm p5J4 33 9Wt K C> Sc TI V r ^ Mil Ft Co Nl Ca Co Al Br Zo 31-let h^o.BJb 44.13* 47.W 30.141 Cr 31.131 S3JI7 31.133 31.70 70.123 g£3JV 39 41 IT 45 »M7*« spym m 53 m Ro Rh Pd Cd ID . Sn 1 Kb 1 Sr Y Nk Ma Tc At Sb Tc 1171 110.103 (A?'JgW''.k n.»l U.IOi fcjoov taw UZEt WW I07.W0 55 P'Str* 57 m 73 'WS^'75^1 PT6*« 79 si.. 82 83 S5 86 1 Tl Oi Al Hi Tl Pb BI Po Al RII Ci 1 Bi HI W [ Re n 307.3 30I.H0 17011 I31.M} bu'-ltt 71 100.141 tit1 San^'VS Ir. 110.107 lour mo) 13111 87 88 89 Fr R. 1 (3131 3».tll 10}

57 59 ei 65 F3I* 67 ••W^ 69 71 Lanthanoid Pro 5m Tb DT Ho Er Tin Vb 13MH HI.1BI lull M»4 131.121 pill 5M MM 170.17 92 89 90 93 j 94 95 96 97 | 98 ,100 1 101 102 10] 91 1 7>, Act :inold Ac Th Am Cm Bk cr •tl Fm. Md. No Lr Pi V N» P" 137.04l| ttiot (III) 1337) | till) 11351 U)!> 233.131 isuso 1231.031 QUI (7071 | 12511 (3301 (337)

240 NEUTRON ACTIVATION STUDY OF MONOMINERAL FRACTIONS OF DEEP-WATER OCEANIC SULPHIDES VAGANOV, P. A. and CHOU RONGSHENG University of Leningrad 199034, Leningrad, USSR Some mineral fractions of deep-water sulphide ores were studied by neutron activation analysis* The analysed sam­ ples derive from domains of hydrothermal mineralization in the zones with different rates of ocean floor spreading. They had been dredged in various sites of the East Pacific Rise and Mid-Atlantic Ridge. The analysed minerals are sulphides of iron, copper and zinc dominated by pyrite, marcasite, chalcopyrite; rarely mslnilcovite, wurtzite and covellite occur. Mass of monomineral fraotion samples was 5-10rag. Sample s of minerals and standards were placed in high purity quartz ampules and were irradiated by epithermal neutrons during 50 hours. Mean density of neutron flux on the cadmium fil­ ter was 5x10 "cm s» Measurements of activity were made with two detectors: coaxial Ge(Li)- and high purity germa­ nium planar detector. About 30 trace elements have been de­ termined including noble metals (gold, silver, iridium), chalcophile non-metals (arsenic, antimonys selenium), side- rophile satellites of iron (cobalt, nickel, scandium), ra­ re earth and radioactive elements. Neutron activation study showed a considerable scatter of trace element concentrations in all the representative sets of a given mineral, e.g. one pyrite set exhibits va­ riations in gold content to cover two orders of magnitude. Such variations suggest hydrothermal origin of this minera­ lization. All examined minerals show higher silver contents as compared to gold .concentrations; silver-gold ratio ex- 3 ceeds 10 whereas this ratio is reduced up to 1.5-2.0 in the sulphides most enriched in gold. Apart from the enrichment in gold and silver, the deep- wa­ ter sulphides were established to have significant concent­ rations of chalcophile non-metals: arsenic9 selenium, anti­ mony. The pyrites usually display the following distribu­ tion pattern of these chalcophile satellites (in increasing order of their content): arsenic-antimony-selenium while gold-bearing chalcopyrites shows selenium-arsenic-antimony.

241 However, the available data do not reveal any strong cor­ relation "between the noble metals and chalcophile elements. Cobalt-nickel ratio which is known from the study of conti­ nental ore pyrites to be indicative of mineral formation temperature, widely ranges in the pyrites* For example, the cobalt abundance in some pyrites greatly exceeds that of nickel; in addition, other pyrites from the same sites of oceanic floor showed the inverse ratio of these elements.

The REE abundances in the studied minerals are much lower than their average crustal abundances. Chondrite-normali- zed REE-distribution patterns reveal a positive Eu-anomaly which is due to Eu ability to change its valence. Selecti­ ve leaching of europium resulted from its reduction gives rise to abnormal REE distribution in hydrothermal fluid. Ore mineralization precipitated from the discharging hyd- rotherms may inherit this pattern, Eu-anomaly being most prominent in. the first high-temperature ore sulphides. However, some investigated minerals lack Eu-anomaly sug­ gesting that they are related either to low-temperature phases or zones of mineral redepasition.

Distribution patterns both of noble metals and index-tem­ perature components of deep-seated sulphide formation are important in terms of geochenical features of primary and secondary sulphide deposits on the oceanic floor. The se­ condary minerals are acceptors of noble metals released by sea-water (or hydrothermal fluid) oxidation of pre-exi­ sting sulphides; they might derived either through an in­ crease in sea-water alkalies or iron reduction. The- secon­ dary minerals may be markedly enriched in noble metals when compared to the primary sulphides.

242 IRIDIUM ANOMALY IN THE UPPER VENDIAN VAGANOV, P.A. University of Leningrad 199034, Leningrad, USSR Instrumental activation analysis using nigh flux of epi- thermal neutrons was applied to search iridium anomaly in the Upper Vendian rocks• Palaeontological data suggest that the earliest so far known crisis in the evolution of animals occurred in Late Vendian times. The majority of Ediacara Metazoa had disappeared at that time, at the bou­ ndary between the Redkino and Kotlin ages. These fossils are found in the Redkino horizon in the East European era- ton and its stratigraphic counterparts in West Europe, North America, Australia, Asia and Africa, It appears that mass extinction of Ediacara organisms has not been folio- wed by the emergence of advanced Cambrian skeleton forms because it is separated by a protracted time-span (Kotlin age). The complete and thoroughly studied Upper Vendian sequen­ ces within a key region for the Vendian system are known within the East European craton. In the Cis-Dniestrovian area, imprints of Ediacara fauna are found in many members of the Mogiliov-^Podolsky Group, The topmost Kalyus member in the Cis-Dniestrovian region is a stratigraphic level corresponding to the time of Ediacara fauna extinction,

Gsochemical anomalies (in particular, rather high iridium concentrations) in sedimentary sequences are known to be related to sharp changes of animal evo3.ution in Phanerozo- ic times, and this suggests that global changes of environ­ ments took place.

Sampling of the Upper Vehdian sequences from the Cis«Dnie- strovian area was"made to reveal a geochemical pattern of sedimentary rocks corresponding to the stratigraphic level of the first biotic crisis,

A total of 31 whole rock samples was '.analysed; the samples of rocks and standards were placed in high purity quartz ampules and were irradiated by epithermal neutrons during 50 hours. Mean density of neutron flux on the oadmium fil- ' J "' • -• i ter was 5x10 cm""2s • Activity for determination of iri« dium was measured in 70-80 days after irradiation in order to lower an influence of spectral lines with energy 311,8

243 and 320,1 keV of radionuclides c-"Pa and p,Cr, Two spect­ ral lines were examined for gamma-raya of 316,5 and 468.1 keV of 192Ir; the detection limit of iridium is 3x10"8 %. Iridium content in the samples from the basal Kalyus mem­ ber is compatible with that of reported from the Fhanero- zoic iridium anomalies. Maximal iridium concentration cor­ responds to a 20m-interval including the boundary between the Dzhurzhevka and Kalyus members, two samples from the basal Kalyus unit contain 5j5x10"' % and 7x10"^ %. High iridium content at the mentioned boundary could not result from a short-term event because a time-span of accumulati­ on of pelitic sediments should be some 100 000-1 000 000 years. So, meteoritic nature of the iridium anomaly mar­ king the stratigraphic level of the Vendian biotic crisis is unlikely to be valid.It is known that both volcanic air-borne particles and ashes are enriched in iridium. Good examples are provided by iridium content in fine fra­ ctions of Holocene and recent volcanic ash ejected by Kam­ chatka which attains (5-7), 10**^ %. The presence of tuffaceous beds in the Redkino horizon from the East European craton and elsewhere in the world suggests an activation of explosive volcanism in Late Ven­ dian times. Changes in global volcanic activity might be responsible for geochemical and climatic parameters of organism environment*

244 A brief summary of EMG's Multichannel Analyzer product range I.Vajda, L.Totb. /Ulec-troiiiqiis Licasurent Gear, Budapest, Hungary/ The EMG is a leading manufacturer of different MCA systems. Our activi­ ties on this field were started in the late 60s, and since then due to our continuous efforts we kept pace serving our customers. Presently we would like to introduce two of our latest MCA systems. The type 38000 (NUC-8000) belongs to the high end, offering solution to the most complex measuring tasks. Featuring four independent Pulse Height Analysis measuring channels, in­ dependent and simultaneous data accumulation and processing, eight chan­ nel multiscaler with zero dead time, and digital oscillography; all sup­ ported by comprehensive software packages running on fast processors. The modular construction allows great flexibility in setting up the right system for the task. The analog front end modules follow the internationally accepted NIM Standard, including HV Biasing Stabilised Power Supplies, Spectroscopy Amplifier + Base-Line Restorer, Pile Up Rejector, Mixer-Router, Analog/ Digital Converter (100 and 450 MHz), Loss-Free Counter, and Multiscaler modules, along with Standard NIM BIN/Power Supplies. For the mass storage of data and programs a dual Floppy Drive is inclu­ ded. The optional peripherals are analog or digital X Y plotter and alphanu­ meric - graphic printer. For 1/0 communication RS 232C and IEC 625 lines are available. The stand-alone control console features touchpanel keyboard, having ASCII and special functions fields with monochrome or high resolution color monitor (option). On special request a second workstation is avail­ able with full-stroke keyboard and separate monitor for programming work. The programming language of the MCA is the BASIC-A and assembler. The 38000 Typ. analyzer system is used among other applications with the ARGUS research reactor for activation analysis as data processing and pneumatic post control instrument. For those who prefer the use of PC based MCA-s we offer the 38100 (NUC-8100) Typ. analyzer system, which is using the same analog signal processing modules, while offering the PC XT or AT computing power. As software support both MCA's are using the ASPR0-NUC packages for full automatic data processing.

245 Pig. 1. Flow-chart of ASPRO-MJC package

246 AN APPLICATION OF DATA ANALYSIS AND EXPERT SYSTEMS TO INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS RESULTS: AN ANCIENT MATERIAL'S PERSPECTIVE

Vanda Vitali Department of Metallurgy and Materials Science University of Toronto Torontoi Ontario M5S 1A4 Canada

Instrumental neutron activation analysis is one of the nost frequently used tools for the study of ancient materials. Its capacity to determine minor and trace element composition of materials and to utilize small samples in a non-destructive manner has made it a very popular and highly desirable tool in archaeometry. Today, it is routinely used to characterize ancient objects and relate them to their centre of production or source of raw materials, to establish the environmental history or objects or to determine their method of manufacture.

The interpretation of multiresponse instrumental information such as the one obtained using instrumental neutron activation analysis requires however the use of equally sophisticated tools for the analysis of data.

This paper explores various statistical and computer approaches to the analysis of data as well as the structuring of those approaches. A case study dealing with neutron activation analysis results pertaining to to a provenance problem of ancient artifacts is used to illustrate the methodological approaches that are developed.

First, data analysis approaches to determining the distribution properties of the data are considered.

Following this determination the data is examined for various correlations and simple descriptive statistics are produced.

Depending on the task at hand and the distribution properties of the data, various multivariate statistical techniques can then be applied. In the case of archaeometic provenance determination, which centres on the classification of objects, statistical techniques such-as discriminant analysis, cluster analysis or correspondence analysis are considered.

Finally, structuring of the standardized approaches to the analysis of neutron activation data using highly formalized tools, such as expert systems, are considered.

247 The paper therefore develops the methodology for dealing with multidimensional data, such as the neutron activation analysis data, points to the advantages and disadvantages of various statistical- and computer techniques, and presents a way of structuring those approaches.

References to specific statistical packages and computer programmes that can be employed for the analysis of data or the development of expert systems will also be presented.

248 DETERMINATION OF WHOLE-BODY PROTEIN IN SMALL ANIMALS BY IVNAA Wang, Haiying Department of Basic Courses, Huazhong Agricultural University Wuhan, Hubei Province, 430070, P. R. China Abstract Determination of whole-body protein in small live animals and domestic fowls may give direct estimate of nutritional status. iThe in-vivo neutron activation analysis of nitrogen can be used to find protein levels In small animals, as 1 g nitrogen =6.25g protein. 1. Irradiation condition Figure 1 shows the neutron irradiation facility for the mea­ surement of nitrogen. Neutrons from Pu-Be sources produce the characteristic gamma rays from the reaction /4N(n, r^N*. There, are three nitrogen peaks around 10.8 Mev energy region. So we ;took the integrated counts from 9-5-11.0 Mev£1j .

LEftO BRICXS BOWED wax

PLASTIC VESSEL BilS.ZScm1

BOO 1600 2*X3 3200 WEIGHT OF UREA(g) figure 1 irradiation facility figure 2 linearity of phantom's counts 2. Linearity of phantom's counts The phantoms, various masses of urea solution in plastic ves-j jsels were used as the standard specimens. It's linearity of nitrogen net counts are shown in figure 2. 3. Measurement and results •A sample of ground meat weighting 6,855g and a same volume phantom with 93.3g of nitrogen of urea solution were used fori experiment. The measurement of meat by IVNAA shows the avera-i ge percentage of nitrogen in the meat=3.3#, (fractional error! 8.8?S) or for protein 20.6$. The measurement of same meat by j

249 chemical method [2] shows the average percentage of nitrogen in the meat=3.46l/b (fractional error 1.1?6) or for protein 21.6 5&. The results by two methods agree with each other within the experimental error.

A live rabbit weighing 2,356g and a same volume phantom with 93.3g of nitrogen of urea sdlution were used for experiment. The results are shown in Table 1. Table 1. Measurement of live rabbit net counts net counts mass of N percentage of N (phantom) (rabbit) ( g ) ( % ) 336 306 253 237 70 72 3.0 3.1 336 331 244 246 68 69 2.9 2.9 337 336 220 260 61 72 2.6 3.1 337 296 262 258 73 81 3.1 3.4 320 315 230 189 67 56 2.8 2.4 293 308 249 284 79 86 3.4 3.7 Prom calculation, the average mass of nitrogen in the rabbit =71±7g (fractional error 9.8'/6), the average percentage of ni­ trogen in the rabbit=3.0^ (for protein 18.8%). 4. Conclusion It is clear that the IVNAA method can be used to determine the whole-body protein in small live animals with the statis­ tical error < 10%. References [1J J. R. MKRNAGH et al, phys. Med. Biol., 22(1977)831 [2j Official Methods of Analysis, Washington D. C. Association of Official Analytical Chemists, 13th ed,1980

250 BACKGROUND INVESTIGATION ON THE DETERMINATION OP NITROGEN BY IVNAA Vang, Haiying Department of Basic courses, Huazhong Agricultural University Wuhan, Hubei Province, 430070, P. R. China Abstract The major problem on the determination of nitrogen in a small body (like Children's body) by IVNAA is the large background compared with the weak signal. In this work, the factors that effect the background in the nitrogen region (typically from 9.8-11.0 Mev) were investigated. The irradiation facility was described previously f 11. 1. Environmental factors It was established that neither cosmic radiation nor the ni­ trogen of the air contributed significantly to the background in the nitrogen region. 2. Random coincidence When two energy gamma rays enter the detector simultaneously, 4 Mev and 6 Mev gamma for instance, their individual energies may sum to give energy that happens to lie within the nitrogei region (10 Mev). The detector will register the result of this random coincidence as a signal in the nitrogen region. If two independent events occur at rates u, and u^, the random coin­ cidence counting rate R is given by £2;]

R=2u;u2x (D where x is the resolving time of the detector system. Apply­ ing the data from the background without sample and equation (1) the counting rates R were calculated. Each pair of gamma rays were such that their energies sum up to a single pulse with energy lying within the nitrogen region. From the calcul­ ation, the all random coincidence contribute about 64$ to the background. 3. Gaussian spreading Gamma rays of energy from 9.0 to 9.7 Mev may give rise to signals which spill over into the nitrogen region by Gaussian Spreading. The Gaussian distribution equation is given by C3J

»«« e "U"m)2/26'Z —(2) where z is the gamma ray energy to be considered small bin. m is the mean. N_^ is the peak counts of gamma ray. C, is the standard deviation of a peak of enery E.. It is given by tf, =<4E,/2.35 , (3)

251 where AE, is the FWHM. Using the result from the background without sample and equa­ tion (2)-(3). The contribution to the background with energis­ es 9.8-11.0 Mev was calculated by the gamma ray energy bin that are situated energy region from 9.0 to 9.7 Mev. The per­ centage contribution to the background of nitrogen region by Gaussin Spreading is 23#. 4. Explanation for the background ratio The background counts (C2) obtained by using two equal sourc­ es were compared with those (C1) obtained by using only one source. If the ratio C2/Ci=4, the background in the nitrogen region could be ascribed to random coincidence. If C2/Ci=2, then the background could be attributed to Gaussian Spreading. But the actual experiment result C2/Ci=3»1. From calculation: C2/C1 =4x(Random)+2X(Gaussian)=4x64#+2x23#=3.02 which is in conformity with the experimental value of 3.1 within experimental errors. 5. Conclusion The background in the nitrogen region is largely caused by two factors, the random coincidence and the Gaussian Spreading.

R© f © x*Qn CQ s £13 J. R. MERNAGH et al, Phys. Med. Biol., 22(1977)pp831-835 [2j W. E. BURCHAM, F. R. S. Nuclear Physics an Introduction, LONGMANS (I963)pp238 [3] J. A. SORENSON et al, Physics in Nuclear Medicine, (1980) pp105

252 NEUTRON ACTIVATION ANALYSIS OF GEOLOGICAL ROCK MATERIALS

Wang Jun , Chen Da , Qian Shaojun Northwest Institute of Nuclear Technology P . O . Box 69 , Xi'an , China

The neutrons passing through the surrounding rock materials , which are released in underground nuclear explosions , have been slowed and absorbed. By interacting with stable nuclides, via various neutron reactions such as (n, y),(n,p), (n , a) and (n ,2n) etc., it can produce activation products . Reference [1] calcu­ lated the activation fractions of different kind of neutron reactions and the activi­ ties of the activation products on the assumption of the condition that none of the neutrons are captured prior to being thermalized with the rock materials . Obvi­ ously , the types and quantities of the activation products are not only depended on the components of rock materials , the intensity of the neutron source , but al­ so depended on the energy spectrum of the neutrons . On this condition , we calcu­ lated the absorption values for all the elements present and the activation fractions for some reactions . The intensity of neutron source was obtained by using the determination of activation nuclides .

The neutron energy spectrum in the rock materials is of great importance to calcu­ late the activation fractions , namely , the ratio of the neutron number produced activation reaction to.the neutron number absorbed by rock materials . This is ob­ tained by using a neutron Monte.Carlo code as discribed by reference [2] .

The component of the surrounding rock materials is detennined by man} nalysis techniques [3 ,4]. The major elements include O , Na , Mg , Al , Si, CI , K , Ca , Ti, Mn and Fe etc. which constitute a total of about 99. 0% , and the neutron absorption of these elements and some minor elements (Li, B , Sm , Eu , Gd , Dy etc. ).consitittite a total of about 98.7% .

The analysis of radionuclides are critical. It is necessary to avoid the disturbance of other activation products . A suitable half life of radionuclide for measure , and

253 complete activation cross sections for reaction channels are available as well . Wc selected the reactions ^ScCn^^Sc^Tbtn,)/)160™ and 180Hf(n,y),81Hf.The concertrations of the elements Sc , Tb , Hf in the rock materials has been esti­ mated by instrument neutron activation analysis [4] . The measuring system in­ clude a Ge (Li) detector , Series —88 multichannel pulse height analyser and PDP -11/34 computer . By using the SPECTRUM — F program , the y — ray spec- trums of the samples are analyzed .The activation fractions of reactions 45Sc(n,)>) «Sc , 15!Tb (n ,y)160Tb and 180Hf (n ,y)181Hf are 0.315 x 10"3,0.743 x 10'4 and 0. 390 x 10~5 respectively .

In our consider problem , the uncertainties of the fractions and neutron source in­ tensity are associated with energy spectrum of the neutrons released to the rock materials , th ^Tiogeneity of the rock materials , parent element concertrations . We think that the distribution of rock materials is uniform in a small sphere .

And , the energy spectrum of the neutrons in rock materials by Monte Carlo code are relative spectrum distribution of unit neutron , it has important influence on the calculation of the activation fractions. For example, on the assumption of neutrons complete thermalization , the actication fractions of reactions 45Sc (n , y).?Sc , ,59Tb(n,r)160Tb and 180Hf (n,y)181Hf are 0.186x 10-3,0.177xl0-4and0.624x 10~5 respectively . Therefore , if we select the reaction in which the trend of neutron activation cross section curve is similar to the neutron absorption cross section curve in the rock materials , the influence of the energy spectyum is eliminable . The determination of the neutron source intensity independent from the energy spectrum of the neutrons released to the environment rock materials .

[1]UCRL-14249 (1965) . [2] Li Yuanchun, "The Monte Carlo calculation of the neutron transported in rock materials ", unpublished (1982). [3] Gao Caisheng, "The chemical analysis of the elements in rock materials ", unpublished (1980). [4] Chen Da , * The concertrations determination of the elements in rock materi­ als by NAA", to be published (1982).

254 A PIXE STUDY OF JHE EFFECTS OF THE ZINC-SMELTING WITH AN INDIGENOUS METHOD ON SURROUNDING ATMOSPHERIC ENVIRONMENT*

Wang Xinfu, Zhu Guanghua, Shen Xinyin, Xiong Duanggui4, Wu Xueqin*, Sun Youping* Institute of Low Energy Nuclear Physics, Beijing, China + Institute of Guizhou Environaental Protection Science, Guiyang, China

Introduction

Serious environment pollution from local smelting industry by way of an indigenous aethod has been attracted people's attention. This paper presents a study on the atmospheric environment pollution caused by heavy metal elements released from Zinc-smelting reaction.

Experimental

Zinc-smelting furnaces are located in a hill region. A 8- atage cascade inpactor was used to collect air particulates in the vicinity of the Zinc-smelting furnaces,and five day period was chosen for the collection in spring, summer and winter respectively in 1988. The average concentration has been determined by PIXE technique for 18 individual elements.

Results and discussions

1. The pollution from elements Zn, Pb, Cd, CI etc. is quite serious in the surrounding atmosphere of Zinc-smelting region* especially in working sites. For above mentioned three seasons, the average concentration of Pb in the atmosphere of the sampling sites is 1.7 to 22 times of the permitted maximum concentration ( 0.7 ug/m3 ) in the atmosphere of residential area, and Cl at working sites exceeds the permitted maximum concentration ( 30 ug/m3 ) also. The average concentration for Zn, Cl, Pb, As and Cd at the sampling sites of the Zinc-smelting region is 8.4-147, 23-117, 3-38, 1.7-32, 24-930 times as high as that at the comparative site of the far neighboring region respectively. It should be noted that the average concentration for Cd is more' than 150 times as high as that in general cities.

2. For the space-time distributions of the interesting toxic

* Work supported by International Atomic Energy Agency, Contract No. 4901/Rl/RB, Beijing Normal University.

255 elements, such as Zn, Pb, Cd, As and S, their concentration is very high and variation is also large.

3.The amount of the identified elements is different in the air particulates of different sizes. For the concentration- time distributions of 18 individual elements, 12 element species concentrate mainly in the fine mode particles ( < 2 jim ). The mass median aerodynamic diameter ( MMAD ) was calculated [1], It is between 0.32 urn to 0.53 um.

4. There are certain correlations in the space and time distributions between elements from the same source. Under the sampling conditions used in this study, the element Zn has strong correlation with Pb, Cd, As, Ni, and has relatively closer correlation with K, Cl, S, meanwhile, Zn, Pb and Cd are intergrowth elements in Pb-Zn raw ore. Another typical element As [2] from burning coal has strong correlation with elements Pb , Cd, Zn, Ni, and has relatively closer correlation with elements Cl, S. Therefore, the atmospheric pollution caused by above mentioned elements should be attributed to the melting raw ore and burning coal in Zinc-smelting process.

Conclusion

The pollution in surrounding atmospheric environment caused by Zinc-smelting i3 quite serious. The concentration of main toxic elements, such as Zn, Pb, Cd, As etc., in the sampling sites is much more higher than that in the comparative site. The concentration of element Pb in atmosphere is 1.7 to 22 times of the permitted maximum concentration for residential area. The concentration of fine mode particles is higher than one of coarse mode particles. The potential toxic elements mainly concentrate in fine mode particles. Their MMAD is very small, which have more harmful effects to human health.

[1] Boueres, L.C.S., Orsini, C.M.Q.,Nuclear Instruments and Methods, 101 (1981) 417-424. [2] Wang M.X., Scientia Atmospherics Sinica, 10 (1986) 46-54.

256 DISTRIBUTION OP SOME ELEMENTS IN HUMAN HAIR AND INTERNAL ORGANS DETERMINED BY NAA

Wang Yinsong, Zhuang Guisun, Tan Mingguang, Zhi Min, Cheng Yuandi Shanghai Institute of Nuclear Research, Academia Sinica P.O.Box 800-204, Shanghai, China

Twenty four male autopsies whose ages were in the range from 35 "to 60 years old were obtained from Shanghai, China. The samples of liver,lung,kidney cortex,brain and scalp hair were collected from the autopsies within 48 hours after accidental death of the persons who were proven in good health before the accidents.The samples were stored in a freezer at temperature below -30°C until taken out for analysis. A brittle fracture technique in liquid nitrogen was used to homogenize all the samples.

The trace elements As,Cd,Hg,Cu and Zn were determined by RNAA. Samples of lOOmg dry weight were double sealed into polyethylene bags and irradiated in a swimming-pool type reactor with a thermal neutron flux of 1x10 n.cm" .sec" for 44 hours. After a cooling period of l-3days, The samples were digested in concentrated nitric acid and sulphuric acid at 150°C for 4 hours in teflon bomb. Then, the samples were extracted using zine-diethyldithio-carbamate and methylisobutyl ketone-iodide as solvents. The elements were sepa­ rated into two groups suitable for gamma-ray spectrometry.

The elements Se,Na,Cl,Mn,Mg,S,Br,Cr,Rb,Fe and Co were determined by INAA. Different irradiation time was used for different elements according to their half decay period. The table 1 shows the condi­ tions of the experiments. The activities were measured by an Ortec Ge(Li) detector coupled to a CANBERRA S-80 4096 channel pulse-height analyzer.

Table 1 The conditions of experiments for INAA Neutron flux Irradiation Cooling Counting Group of n.cm- .sec- time time time nuclides 8X1011 60 sec 5 sec 60 sec ',mSe 24 38 56 Na, Cl, Mn 11 5xl0"""J " 8 min 60 sec 400 sec ?„ ,7 o? ' • 'Ng, 's, Br

^X 51Cr 86Rb 4x10 8.5 hr 2-3weeks 3600 sec ' 59 60 -^Fe, Co

257 This paper provides the "background values of elements for normal persons in local area. The results show great difference in distribution of elements was observed in different organs. Table 2 shows the distribution of several main elements.

Table 2 Analytical results of Chinese autopsy samples in mg/kg dry weight (arithmetic mean + standard deviation)

Hair Kidney Liver Lung Brain As 0.40^0.22 0.11^0.06 0.16±0.11 0.10±0.07 Cd 0.20i0.14 116.18174.1 8.6oi5-32 1.90±1.30 Hg I.I8+O.65 0.62±0.46 0.37^0.26 0.10^0.04 Cu 10.07±2.14 13.42i3.39 34.11^13.65 9.79^3.77 Se 0.62io.24 3.65^0.82 1.45-0.38 0.93±0.32 0.6llo.22 Zn 206.65:^43.3 181.87^71.5 209-74-55.1 54.99-11.16 41.3-5.6

Our results were comparable with that of other contries generally. Some differences are probably caused by different environment and foodstuff. '

258 THE DIAGNOSTIC PRINCIPLES AND PROGRAM OF TRACE ELEMENT ABUNDANCES ON THE PETROGENESIS AND MANTLE EVOLUTION

Wang Yun Liang Chengdu College of Geology

The trace element approach was powerful to solve the major petrogenetic problems. Recently, the main method is direct one: 1. assuming a series of petrogenetic models and calculating them; 2. comparing calculated values and measured data; 3. finding and selecting the most appropriate model for the suite of rocks. The following are the disadvantages of the direct method: 1. the solution is not an unique one;2. the study starts with model assumptions;3. all the models cannot.be systematically tested or rejected;4. it would clearly be very difficult and time-comsuming to test a large number of models of randomly generated parameters and compare the results to the data.

The author try to show a way of thinking which could solve above disadvantages:!, trace elements in a suite of igneous rocks formed by a certain magma process should observe a sinple and universal law of abundnce relationship; 2. the laws of abundance relationship observed by trace elements of igneous rocks formed by different magma processes are different; 3. all recent mathematical expressions which contain different geological categories of parameters for different magma processes are changed into the equations of trace element abundance relationship

259 The author have devised a diagnostic program based on the above thinking.

A suite of igneous rocks unknow in pedogenesis

Linesr magma processes Nonlinear geological processes

-n. 1 ? Non contamination Contamination

I III- Fractional Partial citing 1. Self— mctamorphism Crystallization -5 2. Hydrothermalism W Equilibrium Fractional 3. Alteration and I melting melting mctcsomatism 1. Gravitational • Mantle . processes 4. Halmyrolysis differentiation Source Source 5. Weathering of Crystallization region region 2. Equilibrium heterogeneity homogeneity Crystallization I 3. Cumulus 1. Assimilation minerals and of crustal rock residual magma by a magma 4. Stage of 2. Two magma fractional mixing Crystallization (hybridisation) 5. Adcumulatcs 3. Crustal remelting orthocumulatcs and mcsocumulates

I * II « SI and IV represent the diagnostic principles and methods;quastion marks mean that those diagnostic principles and methods have not been studied and need to study in future. This approach has advantages of: 1.having unique solution of petrogenetic model; 2. treating the measured data objectively; 3. diagnosing the correct petrogenetic model which directly perceived through a diagram of an abundance relationship between two element; 4. being very sinple and easy.

260 MULTIELEMENTAL NEUTRON ACTIVATION ANALYSIS OF DUST PARTICULATES FROM A CEMENT FACTORY IN CENTRAL INDIA R.G.Weginwar and A.N.Garg Department of Chemistry,Nagpur University,Nagpur-10(INDIA) In order to know atomosphere quality,source of pollutants and effect of urban and industrial settlements it is essential to accurately determine toxic trace elements in and around industrial establishments[l].Neutron activation analysis (NAA) has been extensively used for the detection and determination of inorganic pollutants in atmosphere [1-3].We have analysed Fugitive dust particulates from a cement factory,two NBS SRMs (coal fly ash and Urban Particulate Natter) and one proposed standard Pond Sediment from NIES,Japan [4J by instrumental and radiochemical NAA. Dust particulates were collected near coal yard of Handhar Cement Factory,Raipur located in central part of India on different days of December 1987 during 9 A.M. to 2 P.M.by Air Pollution Control Division of National Environmental Engineering Research Institute(NEERI),Nagpur. A locally fabricated air volume sampler was used whence sample was collected on a glass fibre filter paper. After drying it was scratched out using a teflon coated spatula. 20-50mg samples alongwith standards were irradiated at a thermal flux of 10 n cm s in Apsara reactor for |0m,lh and 5h.After proper delay these were counted on a 60cm. HPGe dector (EG & G ORTEC) in conduction with 4096 MCA (Canberra Series 35) at different intervals.Another set for RNAA work was irradiated at thermal neutron flux of 10 n cm s for two weeks whereby Zn,Co,Cd,Sb and Se were determined by radiochemical solvent extraction method [5].About 25 elements have been determined. Concentrations of 9 trace elements (Ba,Mn,Cu,Zn,Cr, Sb,As,Co and Br) in NBS and NIES standards and ranges of concentrations in dust particulates are given in Table l.In addtion concentrations of minor components(Na,K,Hg,Cl,Fe) and other trace elements such as Cu,Cd,Se, Ag,Hf,W,Ga,Th,Sr,La,Sm,Eu were also determined

Data in Table 1 indicate that the range of concentrations of toxic elements is quite large.Hn content is quite high compared to other standards.This may possibly be due to the fact that central parts of India are rich in Mndeposits and its mining in nearby areas may have heavily contaminated air.However,Br and As concentrations are quite low. Evidently Ba,Cu,Zn,Cr and Sb contents in dust particulate are fairly low compared to that for NBS SRM 1648.Whereas Zn content of cement factory dust is comparable to that of coal fly ash and ponds sediment,it is lower by an order of cignitude compared to that of SRM 1648.

261 Table 1.Concentrations of potential toxic trace elements in environmental standards and dust particulates (in /Jg/g) Element Urban Coal Fly Pond Dust Particulate Ash Sediment Particulate SRM 1648 SRM 1633a (NIES) (Mean) Ba 756 i.8 1460 ±^15 138 i 2 158-220 (737) (1500) (N.A.) (198) Mn 873 ±^4 176 ± 1 770 i-8 1270-1610 (860) (179) (770)^ (1440) Cu 612 ±. 9 115 ± 1 213 A 2 208-393 (609) (118) (210) (366) Zn 4810 + 30 221 ± 2 338 ± 5 211-391 (4760) (220) (343) (300) Cr 401 ± 2 198 £ 2 75 ± 1.4 76-194 (403) (196) (75) (161) Sb 43.2^fc 3.2 7.2 + 0.5 3.1 + 0.2 (8.8-14.7) (45)* (6.8) (2.0) (11.6) As 111 ± 1 150 ± 2 12.0 i 0.3 5.2-10.3 (115) (145) (12) (7.4) Co 18.5 ± 0.6 43. U± 0.2 28.O±0.4 18.8 -43.7 (18) (46)* (27) (27.2) Br — 529 16.1* 5.4-11.2 (N.A) (500) (17)* (7.9) Concentration values in the parenthesis are certified or reported in the literature.For dust particulates,however, these are arithmetic mean.* marked concentrations are .reference values only It is observed that concentrations for NBS standards are within ±5% compared to those of certified and literature values[l] For most toxic elements determined in this study, mean concentrations are low compared to that of dry deposition in Bologna, North Italy [1] except for Cr and Mn.These studies indicate that air surrounding cement factory area is reasonably safe as far as most toxic trace elements are concerned. More extensive studies are in progress and results will be presented Acknowledgements:-He are grateful to Department of Atomic Energy,Govt.of India for financial support. References:- [1] Morselli L., Zappoli, S., Gallorini, M.,and Rizzio,E., Analyst,113 (1988) 1575-1578. [2] Hard,N.I.,Kerr,S.A.,0tsuka,T.,J.Radional.Nucl.Chem.Art., 114 (1987) 113-123. [3]Hamilton,E.P.,Chatt,A.,J.Radioanal.Chem.,71(1982)29. [4]Soma,M.,Seyama,H.and 0kamoto,K.,Talanta 32(1985)177-181 [5] R.G Heginwar and A.N.Garg, Radioehem.Radiat.Chem.Symp. IGCAR,Kalpakkam (1989),RA-1

262 Quantitative calculation of the Charg'ed Particle Activation Analysis with Channeling Determination of Lattice Location of Trace Amounts of Carbon in Gallium Arsenide Crystal

KEI Lun-cun BAO Shanglian YANG Qixiang YANG Xihong Institute of Heavy Ion Physics, Peking University, Beijing 100871, P. R. China

The Charged Particle Activation Analysis (CPAA) is very sensitive to analysis the light elements, such as C, X, B, 0. It is specially used in the trace light elements analysis in semi-conductors and other high vmrity materials. But in the semi-conductor researches, i I is more interesting to know the impurity atom's lattice locations. The combination of CRAA and the channeling technique can determine the impurity's lattice location at the same time of the concentration determination. A French group at Orleans has done some interesting experiments in this respect, but they have not determined the partial concentration of the impurity atom's on the different lattice locations.

Our work, based on the continuum model of the Molieie screened potential, calculated the flux distribution of the incident channeled particle along <100> and <110> directions in GaAs crystal and the ratio of the stopping powers of GaAs for the channeled and random irradiation deuterons. This flux distribution and the ratios of the stopping powers were included in the K^ parameters:

A K c +K -*<<^)/ rand(3m=( l(«'0)*[ ll 2^0)*tC2]+K3(o'G)*[C3]/[CT]

A r A c +K << 0)/ raiKlan=(K4^0)*[ ll 5

[CrJ = [Cjj + [c2j + [c3]

Wiere: A , A and random are the radioactivities produced from the element to be analyzed by the irradiation along <100>, <110> and random directions respectively; [Cr] is the impurity's total concentration in the sample and [Cj], [C2], [C3] are thd partial concentrations on the octahedral interstitial, substitutional and deformed octahedral interstitial positions in GaAs crystal.

263 A group of the experimental results of the carbon in GaAs by M. A. Misduq [1] "as used Cor an application of our calculation. It was found that; in i^DWE GaAs sample at lower carbon total concentration ( (vO.oppni), the carbon atoms occupy principally the octahedral interstitial and deformed octahedral interesting position (>60%), but at ligh total concentration (~2ppm}, the substitutiorWcarbon plays a dominant role (>80%)[fig. 1].

[1]. M.A. Misdaq et al, N'ucl. Instr. Meth. B15 (1986) 480

[CiJ/CCy](0.25 Unit)

[CT](0.5ppm Unit)

Fig. 1. Variation of the carbon concentrations on the octahedral interstitial(B) , the substitutional(A) and deformed octahedral interstitial(c) positions as function of the total concentration{[C™]).

264 CULMINATION OF TBACE SLSKiSTS I" SAKrLES OF ANTARCTICA 3Y SEGTEON ACTIVATION ANALYSIS "

V/u Yuguang *Zhao Junlin Institute of Low Energy Nuclear Physics, Beijing Normal University, Beijing, China Institute of Environmental Pollution

Neutron Activation AnalysisOTAA) has an advantage of highly sensitivity and simultaneous multielement analysis. So that in recent years it become one of the most promising and attractive analytical methods. The method has bean widly appled to study geological,biological and environmental materials:. Especialy7 some rare samples were collected from Antarctica. We hope that more informations would be got with the samples using !?AA.

Experimental Samples and standard preparation The samples were collected from Antarctica and stored in prastics bottles, proviously cleaned with dilution nitric acid and rinsed with deionized water. Samples of 20-30mg were weighed and sealed in small cleaned prastics bags. A series of GSD standard were selected. The standard prepara­ tion was the same as samples.

Selection of method The amount of samples is very rare and valuable. In order to get more information, we consider a good method which combination short irradiation with long one should be adopted. Becanse we are lacking in knowledge of the samples composition. Some elements have not prepared relavantstandard to compare. So "single comparator Ko method" has been selected as assistant way.

Irradiations and counting Short irradiations were performed for 3 min with a flux of 2.5x1011 n» cm~^» i>"" 1 in the pneumatic rabbit. The cooling times were used for 15 min. A usual Ge(Li) detector with multi­ channel system and SPAN program were used. The concentrations of major, minor and micro elements were measured. They are Al, Ca, Cu, Mg, Kn, K, Dy, Na, Ti, V and so on. The samples which have been short irradiation could need cooling for several mouths. Then the small samples bags were cleaned and wraped up in a piece of Aluminium foil. Long irradiation were carried out for 7 hours inside the reactor care with fluxes of (4-5)xl0'3. n.cm""2.s-l, According the different half-life the neasurements have been done in twice. The cooling times were selected for about 7d .and 20d. Wore than 20 of micro and trace elements have been measured.

265 Results and discussion Most elements concentrations were measured with relative ccrr.perison method. Only a few elements have net rot corre­ sponding standard. Therefore a single comparator method has been adopted. Ye and 5c were selected for coraparetors and calculated a series of Ko. Using Ko, several elements concentrations which have teen defined were calculated. General, the error between calculated and defined value was no more than iQ?;. It is can be seen that the calculated elements concentrations are reliable. Using above-mentioned methods more than 30 elements have been measured, such as Al As, Au, Ba, 3r, Ca, Ce, Co, Cr, Cu, Dy, Eu, Fe, Hf, Hg, K, La, Kn, Kg, Ka, Nd, Tvi, 5b, Sc, Se, Sm, Sr, Ta, Tb, Th, Ti, U, V, Ybt Zn in samples of Antarctica. The results would have been very valuable for studying the geological structure, the formation of earth crust and environmental pollution.

266 SEPARATION AND PURIFICATION OF 99Tc FROM SIMULATING HIGH-LEVEL RADIOACTIVE LIQUID WASTES

Wu Zhiqiang Jinniu Monitoring and Management Station of Enviroment, Chengdu 66Cha Dian Zi West-street, Chengdu, Sichuan, China

A reversed-phase partition chromatography for separating technetium and ruthenium was described. Separation of fisson product 99Tc from simulating high- level radioactive liquid wastes with quaternary ammonium 7402 was realized. The method for technetium was very selective, and for ruthenium its decontamination power was high. The experimental results indicated that the 99Tc recovery rate was 90%, and the 103Ru decontamination factor was 1.0E-O3. The ruthenium carrier was determinated with spectrophotometry. Apply this method, the excellent results were obtained.

The constituent of the simulated liquid show up to table 1.

Tab. 1. Constituent of the simulated liquid

Ion I Ha+ Sr+I Zr+4 Ba+a Ce*3 Pr+J Nd+S Concentration mol/m'I 243 8.22 31.4 8.08 16.6 11 27.5

Ton I Fe3 Mn" Cr+3 Ni+a Ti+* Mo+6 Concentration mol/m'I 90 1.46 13.9 6.13 0.67 30.9

Simulating liquid is adopted with formaldehyde solution (or formic acid solution) denitrated. After simulating liquid denitrated, it is added that ruthenium carrier and ammonium pertechnate solution, in case of Pll equal 2, high-level radiative simulating liquid of mixture, fission products have been made. In high-level simulating liquid, what with 99Tc carrier 1.62 raol/m3, and with Ru carrier 4.95 mol/mJ.

In 25 ml separating funnel, add to the simulating liquid 10 ml, the quaternary ammonium 7402 100 mg, the samples extract neutralization 30 min. After lamination, absorption liquid 0.1 ml in the radioactive measurement plate on hygroscopic paper. Under infrared lamp dry, the samples radioactive activity ras measured in beta measurement set. At last count the result.

The high-level radioactive simulating liquid run into extract chromatographic column contained the 400 mg quaternary ammonium 7402. Simulating liquid was passed extract chromatographic in the speed of 2.6 brace volume per hour, the samples run out liquid was collected in a time. When extract chromatographic column adsorpted saturation, the extract chromatographic column was held to the radioactive background level with distilled water. After a while, the extract chromatographic column was reversal-extracted with 8 mol/1 nitrate acid solution

267 in the speed of 2.6 brace volume per hour. The reversal-extract liquid samples wore collected in a time.

Whether adsorb extract liquid or absorb reversal-extract liquid. It was absorbed liquid 0.1 ml on the hygroscopic paper in the radioactive measurement plate (the reversal-extract liquid need to liquefact 100 time). Under infrared lamp dry, the saaples radioactive activity was measured in the beta measurement set.

When high-level radioactive simulating liquid ran off extract chromatographic column, the sanples was separated with distillation method. The ruthenium (IV) chlorine complex was prepared with direct oxidation method. The samples absorptivity was measured with 1 cm colormetric cell, the agent voidage made confer, while maximum absorb wavelenght of the complex is at 484 nm. The reversal-extract samples were determinated with direct oxidation method.

Different radioactive nuclides single was added into simulating liquid in the shap of nitration. The simulating liquid was agitated homogeneity. Radioactive count before decontamination was determinated. The simulating liquid comprised different radioactive nuclides was passed extraction and separation. The radioactive count was determinated again. As against before decontamination and after decontamination the radioactive count so that obtained that of decontamination factor of the different radioactive nuclides. The decontamination factor for different radioactive nuclides show up to table 2.

Tab.2 Decontamination factor for different radioactive nuclides

Radioactive nuclides 1 Pm ,37Cs vZr-wHb VY "3Ru 1 201798 854490 Before decontamination Bq 1 686900 185536 89142 1 After decontamination Bq I 36 64 102 42 88 1 - 2.9xl03 1.9xl03 2.0xl04 l.OxlO3 Decontamination factor 1 1.9x10

[1] Zheng Jishu, et al.(1977) Atomic Energy Science and Technology V.l P.61. [2] G. Kock et al.(1973) Synp.On the Management of Radioactive Wastes from Fuel Reprocessing P.1081.

268 DETERMINATION OF 14TYPES OF CHINESE TEA BY INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS

Xiao Jiazhu Institute for Standardization of Nuclear Industry P.O.Box 982, Beijing, China

The application of activation analysis in life sciences has became more and more widespread. Recently activation analysis has been paid attention in agriculture. Many scientists have determined microelements in agricultural products by NAA. Tea is very important agricultural product in China. Almost every Chinese drinks tea everyday. Also tea is one of most important commodity in foreing trade in China.

This paper describes determination of microelements in 14 types of Chinese tea by INAA. It was the purpose of this work to determine the distribution of this work to determine the distribution of microelements in various tea and to research relationship between amount of microeleIments and quantity of tea. In resent years, growing of Chinese tea has spread to red soil and loess plateau. So it is very important task to research microelements in tea. We determined 19 microelements in 14 types of tea by reactor neutron activation analysis.

1. Materials and Method (1) Samples and Standards a. Tea Samples 14 types of tea were from various places in China in 1984. They were provided from Native Product Company of Foreign Trade Ministry of P.R.C. Tea samples dryed in oven at 80*C for 4-5h. Then milled them into powder, homogeneous mixture, weigh accurately 30Q-4QQmg samples powder, it were holden in high pure aluminium sample box. b. Standard We used two types standards. One is U.S SRM-1571 Cfruit leaf) . Weigh accurately 300ns and was holden in high pure aluminium samples.ilaft.The other is single and multielmental standards. Taking 30-40mg standard solution dropped on quantitive filter paper dryed and packed by high pure aluminium foil. (2) Experimental Method a. Irridiation Samples and standards were packed together, high purity iron wire was used as neutron flux monitor. Samples and standards were irridiated in reactor, Atomic Energy Academy. Thermal neutron flux was about 5.7X10'VM2.S. Irridiation time was about 10h. b. Measurement Irridiated samples and standards were tranfered separetely into two polyethylene measuremental tube. Samples and standards were

269 measured in .same geometry situation by Tradic-C system C multichannel analyzer).Twice tracing Measurements were done for every sample and standard.After cooling 3-5d, first tracing measurement. Tue measurement of 69*Zn, 76As, 82Br, 24Na, 42K and 140La nuclides. After cooling 15d measured141Ce, 46Sc, 131Ba, 223Pa, 51Cr, 152"4Eu, 86Rb, 59Fe, 60Co, 124Sb, 181Hf and 134Cs nuclides. (3) Disscusion a. We determined 19 microelements of 14 types Chinese tea content rangs of these elements are following, As 0. 20-1.03ppm, Br 1.37-6.97ppm, Na 21. 86-146. 57ppm, K 1. 6 2%-2. 155k>, Zn 14. 0-17. Oppm, Ce 0.46-2.06ppm, Ca 0. 26*-0. 46*, Ba 12. 9 2-44. 85ppm, Th 0. 06-0-23ppm, Cr 0. 12-1.52ppm, 0.93ppm;Eu 0. 02-0.06ppm, Cs 0. 0 2-0. 13ppm, Sc 0.08-0.24 ppm, Rb 1.87-118. 59ppm,Fe 207-690ppm, Co 0. 22-0. 7 lppm, Sb 0.01-0.07ppm; Ca 0.60-2.05ppm; Hf 0. 01-0. 09ppm. b. Distrubance Thanks to resolution of detector that was 4.5kev, so we could not distinguish 554kev peak of 76As from 564 kev y peak of 122Sb. Therefore we measured As using 657kev y peak.1115 kev peak of :Zn and 1120 kev peak of46Sc were not distinguished. So we used 438 kev y peak when Zn was measured. Because after 3-4d, measurement of mZn was done, Zn element in most sample couldn7t measure.UsualLy deter-mination of Ca is done through 49Ca. But half life of 49Ca is id Al 8.8 min, so it can7 t been measured. CaCn, 7 , p ) Sc reaction can been used to measurement of Ca. Half life of 47 Sc is 4.7d. Only 7-ray energy of4Sc is 160kev.

270 SIMULTANEOUS DETERMINATION OF N,P,K IN PLANTS BY 14MEY NEUTRON ACTIVATION ANALYSIS (FNAA)

Xiao Jiazhu Institute for Standardization of Nuclear Industry P.O.Box 98 2, Beijing, China

N, P and K are three important elements in plants. Usually they aredetermined by chemical methods; but the procedure of samples detailing is complex and the determination isn't simultaneous. Using 14Mev NAA has some advantages, (1) determination can been done by living samples; (2) very rapid rate; (3) Measured seads still can beengrown. Thus FNAA provides a new methods for determination of N, P, K of a lot of plants samples. Nuclear data about N, P, K showed in following table I

Table I Nuclear data about N, P and K elements

element isotopic reaction main v -ray energy half life abundance* kev min

N '% 99.6 '*NCn, 2n)°N 511 10

N ?,P 100 MPCn, 2n)3°P 511, 2240 2.5

%( n, a fAl 1780 3.3 3 K J*K 93. 1 fo n.2n.^K 511, 2160 7.7

1. instrument and equipment Samples were irridiated by Sam-S accelerator! l4Mev neutron was produced by CD, T) reaction. Sam-S accelerator is with a double air-automatical rabbit systems. Energy resolution of DGL20 GeCLi) detector ( against 1.33Mev 7 -rays) is 4kev. It's efficiency is about 21s*. 2.preparation, irridiation and determination of samples and standards Samples and standards, lg plant samples were held in plastic sample box. Standards consist of glucose matrix, then homogeneous mixture, finally lg standards were held in plastic sample box. High pure- aluminiuh foil was used as internal standard. Samples and satanards were irridiated by 10 ft/cn2• s neutron flux. Irridiation, cooling and determination time were separately 10, 1 and 10 min. 3. application We used FNAA to determine N, P and K in wheet, maize, Chinese Sorghum and bean samples. The results by FNAA showing in table II.

271 Table II The result of determination of N, P and K by FNAA

^^-^^contentC*) -^^^ N P K seeds name ^^^^^^^ ^""^->^_ wheat Cwinter 767) 2.44 0.33 0.41 maize C503X 177) 1.70 0.14 0.34 sorghum (p721) 2.04 0.27 0.42 bean CHei Longjiang) ' 6.36 0-49 0.20

Their relative standard basis are separately [$-3**, P-5», K-69*. 4. discussion a. We had used glucose powder, quantitive filter paper and celluloid as matrix of standards. Experiment showed that glucose and quantitive filter paper suited to preparing matrix of standard. Celluloid couldn't been used as matrix, because it contains some interferent elements. b.A compound 7 -ray spectrum was resolved by matrix method.Because small silicon in plants can interfere with N, P and K. So we must deduct 51lkev peak of silicon from measuremental 511kev total peak..

272 DETERMINATION OF SOME TRACE ELEMENTS IN HAIR OF DIABETICS BY ENERGY-DISPERSIVE FLUORESCENCE METHOD

Yang Huazhong Dep. of Modern Physics, Lanzhou University, Lanzhou, China P.O.Box 44, Lanzhou, China

The trace elements are indispensable in human body. Diseases of human body has a direct bearing on the metabolism and equalibrium of the trace elements. Through the determination of the trace elements in human hair, scientific basis are provided for the prevention and cure of diseases. The trace elements in hair of diabetics were analyzed by using241 Am X-ray fluorescence method.

Experimental method: X-ray determinations were performed using a measuring system which consisted of a Si(Li) detector with a window area of 113 mm2, FWHM-210 ev for 5.9 Kev and a Canberra 4096 multichannel analyzer. 24,Am radioisotope of an activity of 1.4 x 109 Bq was used as the source of exciting ra­ diation. The time of measurement was 1000 s. The Ka emission line of each ele­ ment was used. In order to minimize the interference of Compton scattering, the special instrument was deviced.

The hair of a certain position of diabetics was collected. It was cleaned by the fol­ lowing steps: ~30 min in 1% Haiou detergent; wash in distilled water times and again; rinse in deionized water; rinse in alcohol and deionized water. Then, it was desiccated in desiccator, a certain quantity hair was reduced to ashes at high temperature. Then put following material into the ashes: 30 fi\ of diluted nitric acid* 20 fil of standard solution Y and 10 /d of extended solution. After chang­ ing into homogeneous mixture, it was dropped on polycarbonate film. The mass—per-unit-area values of the targets are ~ 2mg/ cm2 and diameter is 10 mm. Such examples can be regarded as thin layers, the intensity of a characteris­ tic X—ray line is approximately proportional to the concentration of the standard solution of each element. A liner relationship factors were found between the concentration in the standard solution of each element and the concentration of the standard solution Y.

Results and discussion: The hair of 23 diabetics was collected, whose ages are in the range of 14-64 years, and two of them are IDDM, the others are NIDDM.

273 The majority of them, except individual person, take medicines of different kinds, and are still under the treatment in hospital. The concentrations of Ca, V, Cr, Mn, Fe, Co* Ni, Cu, Zn and Pb elements in human hair were de­ termined by the above described method. The values of main elements are pres­ ented in Table 1. Table 1. The values of main elements measured in human hair (ppm) Zn Cu Ca Fe Cu/Zn diabetic 137± 14 16.2 ±2.4 866187 23.413.1 0.118 health 179± 18 9.8±1.5 14371144 20.512.7 0.0548

The measured results of the diabetic have been compared with those of the healthy person. The data in Table 1 show Zn of the diabetic is a much lower con­ centration than the healthy, Cu is higher, and the value of Cu / Zn is larger,and Ca content is lower. The reseans for the lack of Zn of the diabetic are: Owing to the strict control of food and drink for a long time, and the food contained more Zn can not be supplied promptly; The concentration of Zn in urine of the diabetic is more than the healthy, and Zn is lost more; The requirement Zn of a sufferer from diabetes complication is higher than the healthy; Body of daibetics often has injuries, making a quick recovery needs more Zn. Owing to the lack of Zn of diabetics, the capacity of their immunity is much weakened. Thus it can be seen that to build up diabetic's health with nourishing Zn or the food contained more Zn is very necessary, and some diabetes complication can be alleviated and it is also favourable for the prevention and cure of diabetes complication.

Values of several trace elements measured are listed in Table 2. The element Fe, Co, Mn, Pb and Ni contents of diabetics are in agreement with the healthy person within experimental error. Ti and V contents of the diabetics are higher than the healthy person, and Cr content is over two times, and Cr contents of some of diabetics are several times. Therefore, metabolism and equalibrium of the trace elements for diabetics are very important. They affect other metabolism and lead to metabolic disorder. Table 2 The values of several trace elements measured in human hair (ppm) Ni Co Cr Mn Pb Ti V diabetic 0.806 1.03 3.07 4.73 5.64 4.13 0.498 health 1.17 0.993 1.44 4.10 5.75 2.78 0.275

274 ANALYSIS OF ELEMENT CONTENTS IN FOSSILS OF THE ANCIENT VERTEBRATES USING ^Am XRF METHOD

Yang Huazhong Song Shizhan (Dep. of modern physics, Lanzhou University, Lanzhou, China) Gu Zugang (Dep. of Geology, Lanzhou University, Lanzhou, China) P.O.Box 44, Lanzhou, China

Element contents of the fossils of the ancient vertebrates found in the village of Shangtamei, in Gonghe County, Qinghai Province and the Zhoukoudian of Beij­ ing were analyzed by X—ray flourescence using 24,Am as an excitation source. Measured fossil samples have horse bone: metacarpal bone, molar, lower jawbone and front tooth; antelope bone: horn, tooth and lower jawbone; deer bone: metacarpal bone and canine tooth; elephant bone: molar; rhinoceros bone: tooth enamel; and lower jawbone of carnivorous animal. The fossil ages are about (0.7— 1.5)Ma. Modern bones are hare lower jawbone and molar. Ana­ lyzed elements have Ca, Fe, As, Sr, Ba, La, Ce and Y.

Experimental method: The 241Am source has an activity of 1.4 x 109 Bq. The window area of the Si(Li) detector is 113 mm2, the thickness is 5 mm and the en­ ergy resolution is 210 ev FWHM at 5.9 Kev Of Mn X—ray. In order to minimize the interference of Compton scattering, the detector is located at included angle > 45° relative to the direction of the excitation of source and angle 45 ° rela- ' tive to the sample plane, samples were placed on a supporting framework with 250 /zm polycarbonate. The experimental spectra were analyzed with the 4096 multichannel analyzer.

(1) THe standard samples were made of Ca3(P04)2 in which the different quanti­ tative standard elements were mixed. Each mixed standard sample was uniformized, then separated into three portions, weighed out 400 mg from each portion. The fossil samples were ground into powder. Each fossil sample is 400 mg in weight. The powder samples were pressed in pellets of 15 mm diameter. Calibration curves for each element were prepared by irradiating a series of accurately weighed standard samples, and the fossil samples were analyzed under the same conditions as the standard samples. The weight fraction Ci of element was given according to calibration curve.

275 Result: The measured element contents of the fossil were calculated using a calibration curve. Being main element of animals bone, Ca content in all meas­ ured elements is the highest and is in the range of 35.1% — 39.2% in weight. Ca with Sr and Ba is related, their quantivalence being bivalent, Sr and Ba contents1 also higher, and are 627—2635 ppm and 427—1596 ppm, respectively. La and Ce contents in the fossils of deer bone are very high, and the others are lower. As el­ ement is poisonous. It exists in all measured fossil samples, and its content is in the range of 39—4730 ppm. Some fossil of animal includes a considerble amount of As. It is possible that its content might be related to the environment in which the animals had lived and died, such as climate, feed and water, or depending on As content of soil in the process of forming fossil. Besides Ca Fe content is the highest, in the range of 0.8—121 mg / g. The influence of Mn was taken into consideration in measuring Fe content of the fossils. Mn content is very low, its influence upon Fe is so small that we can neglect it. Trace Fe only exists in mod­ ern bone at this region. Not only the fossils in this region, but also the fossil of Zhoukoudian of Beijing contains a great amount of Fe. Colour of some fossils is brown, some are black and brown, and some are black. It follows that Fe has play an important part in the process of forming fossils. Therefore, these fossils have been formed when Fe—compound was deposited in dead animals bone.

Conclusion: Owing to the fact that the difference between Ca contents (35.1% —39.2%) in the fossils and Ca contents (36.8%—37.4%) in modern hare bone is not large, that Fe contents of measured fossils are very high, and that the fossils colours are darker, it is clear that these fossils were formed by silicate, carbonate and gypsum not having been deposited in animals bone, but they were formed by Fe—compound having been deposited in animals bone(2); Many ani­ mal fossils are traditional Chinese medicine ( popular name is fossil fragments). Due to different kinds of fossil, and the geographical conditions and position, and climate difference, and disparity in age and so on, elements and their con­ tents of fossil are different. Some elements are poisonous, for example As, it is harmful to human body; Owing to the fossil formed by Fe compoud deposit, there must be conditions of the moist climate and the soil of forest. Measured fossils are elephant, horse, deer, antelope and carnivorous animals bones. These animals lived in humid air and a dense forest. Thus it can be seen that cli­ mate is moist in this region at that time.

(1) Song Shizhan et al., Chinese Science Bulletin Vol. 34, No.10 (1989)877—879. (2) Cheng Jingsheng, Actu GeoGraphica Sinica, Vol.35, No.l (1980)24—31

276 A PRELIMINARY STUDY ON THE TRACE ELEMENT GEOCHEM­ ISTRY OF BASALTIC ROCKS FROM THE TANGBALE OPHIO- LITE IN THE WESTERN JUNGGAR, XINJIANG, CHINA, BY NAA

Yang Ruiying, Dong Jinquan, Huang Zhongxiang, Han Song, and Jia Xiuqin Institute of High Energy Physics,Academia Sinica P.O.BOX 2732, Beijing 100080, China

The abundances and patterns of trace elements can provide useful informations on the sources and evolution of various types of rock and on their economic values in ore deposit prospecting. Such studies require a simple and accurate analyti­ cal technique for simultaneously determining trace elements in a large number of samples, INAA is one of the favorable methods.

Some exposures of basaltic rocks of Ordovician ophiolite are distributed in the southwestern part of western Junggar, including some pillow and massive laves associated with ultramafic rock bodies. In order to study the tectonic environment and origin of these rocks, the concentrations of several trace elements (Rb, Ba, Sr, Ni, Cr, Co, Zn, Sc, U, Th, Hf, Ta, Zr, and REE) have been measured in samples, The analyses have been made with instrumental neutron activation analysis with the accuracy of better than 5%.

On the basis of the REE geochemical behaviors, the basaltic rocks of the Tangbale ophiolite belt can be divided into three type. The rocks in the first type have total 8REE from 10.7 to 32ppm and chondrite normalized REE pattern is slight depletion of LREE and their (La/Yb)cn ratios range from 0.686 to 0.86. The REE patterns are consistent with the typical REE patterns of the mid ocean ridge basalt. The geochemical features of these rocks are typical of either N- type mid ocean ridge basalts or island arc tholeiites. The rocks in the second type have the total 8REE from 18.6 to 26.3ppm, their (La/Yb)cn ratios range from 1.34 to 1.85 and show a slight LREE enrichment, and are similar to those of the basalts in Lan Basin.The two type basalts show very slight fractionation and composition of basalts are rather close to the initial tholeiitic magmas.

The rocks in the third type have the highest REE content. Their chondrite nor­ malized REE patterns are LREE strongly enriched type. These Calc-alkalic and alkalic volcanic rocks are the products of mixing magma which were formed by

277 • contamination of the basaltic melt with crustal materials.

In Tangbale basalts, the normalized to chondrite average abundances of transition metal elements show strong depletion Cr and especial Ni, indicate that olivine was the predominant fractionating phase. The rocks of the first and the second have similar pattern, their Ti/.Y ratios remain constant of values (21.9 and 24.6 respectively) which are close to but lower than these of average of N-type MORB (36) suggesting that these two basalt types from Tangbale have a similar mantle source. According to diagram Zr/Y vs Zr (Pearce et al.,1980), melting degree of the upper mantle forming basaltic magma probably is 15%.

Tectonic setting of volcanic rocks determined using trace element abundances show that they were erupted in the back- arc basin. The volcanic rocks of the early and middle stages of the expanding period have low-REE and other incompatible ele­ ment contents, their total content of S REE is 10.?-• 32ppm,chondrite-normalized REE patterns are LREE depleted and LREE enriched type, there is a smaller negative En anomaly (Eu/Eu*=0.82-1.02).In late stage basaltic andesite or an- desite were erupted in many place. Their chondrite- normalized REE patterns are LREE-strougly enriched type.Other incompatible elements are strongly enriched as well. These Calc-alkalic volcanic rocks are the products of mixing magma which were formed by contamination of the basaltic melt with crustal materials.

[1] Pearco A.J., Phil Trans. R. Soc Lond., A300,(19S1), P299-317.

[2] Wood D. A., Earth and Planetary Science Letter, V.45 (1979) P.326-336.

278 IDENTIFICATION OF MARINE AEROSOL COMPONENT BY COM­ BINED NEUTRON ACTIVATION ANALYSIS AND SCANNING ELEC­ TRON MICROSCOPY WITH X-RAY ANALYSIS

Yang Shao Jin Institute of High Energy Physics,Academia Sinica,Beijing, China Zhang Yi Ming Scientific Instrument Factory,Academia Sinica,Beijing,China

Marine aerosols can often contain substantial quantities of land-derived material resulting from wind erosion, volcanism and man's activities. Identification of the continental and marine components of these aerosols is essential to our under­ standing of the geochemical cycles of the elements, and the transfer of material from continents to the ocean via atmosphere. This paper will describe the com­ prehensive analysis of a marine sample from the western Pacific ocean by INAA and SEM/EDS (including X-ray map and image process).

Concentrations of 30 elements in aerosol particles collected in western Pacific ocean have been determined by INAA. The element concentrations of Na,Mg,Cl,Ca and Br were dominated by marine sources, the enrichment factor (EF) of these ele­ ments relative to Na in seawater is almost equal to unity. Atmospheric inputs of aluminosilicate particles from crustal weathering controlled the aerosol parti­ cle concentrations of Al,Fe,Mn,Sc,Co,Cs,Ba,La,Ce,Eu,Sm,Ta,Tb,Hf and Th. The crustal element concentrations decreased with increasing distance from land over the ocean area close to Asia land and fluctuate around its average value over the remote ocean area. The good relationship between Fe and Al as well as Fe and Sc indicates that Al and Sc have similar behavior to Fe and basically come from the same source. The volatile elements of As,Se,Sb and Zn exhibited average at­ mospheric concentrations that were higher than those expected from the flux of sea salt or the continental dust. It is suggested that the volatile elements over the western Pacific were influenced mainly by long-range transport of anthropogenic pollutants from land. The elemental concentrations-size distribution of aerosol over the western Pacific show that those seawater elements Na,Mg,Cl and Ca had similar size distribution and the crustal elements Al,Fe,Sc etc are quite different from seawater elements in size distribution. Raemdonck et al.[l] also reported that the size distributions of crustal elements over the remote ocean are remark­ ably similar to those of the major seawater elements, and cited the mixture of crustal aerosol particles with sea-salt aerosol as the explanation. In order to iden­ tify marine aerosol component originated from the continent or ocean, the aerosol

279 particles are examined by scanning electron microscopy combined.-with energy dispersive X-ray spectroscop3r. Particle phase structure shows that NaCl crys­ tal which from marine ) in the center of the particle, and the main composition of covered material is Fe ( which from continent ). This observation explains the fact that the crustal aerosol particles are not present as internal mixtures with sea-salt aerosol. Therefore, the size distributions of crustal elements are different from those of the major seawater elements, and it also proved the long-range transport of crustal elements from continents onto the ocean.

REFERENCES

[1] Raemdonck,H.,et al, Chemistry of marine aerosol over the tropical and equatorial Pacific, J.Geophys.Res.,91,8623-8636,1986.

280 AH INVESTIGATION OF MlilllOD FOR DETECTING EXPLOSIVES

Yo Zongyuan U Yubing Ding Shengyao

Bao Zongyu Yang Yiaoyun Rong Chaofan

• Division of Metrology, Institute of Atomic Energy

P.O. Box 275-20, Beijing

'102413 China

The bomb concealed in bag has threatened to human life and

property throughout the world's traffic. Using nuclear technique to detect the explosives is a very significant job. We have tested a method for exploiting explosives.

The amount of both nitrogen and oxygen contained in the modern explosives is larger than corresponding other goods such as nylon, silk etc. The. bag was irradiated by fast neutrons coining from a neutron generator. The gamma rays from the reaction of N, 0 nuclei with neutrons'were recorded by the gamma detectors, e.g., Hal(TO scintillation counters. Therefore, the detection of the presence of nitrongen and oxygon in high contents and high concentrations may be indicative of the presence of a bomb. From the results of preli­ minary experiments it seems that the method is a promising one, be­ cause of the strong transmission ability for both the fast neutron and emitted gamma rays.

The present method may provide a realizable, relative simple and not too expensive apparatus.

281 PRECONCENTRATION FOR NEUTRON ACTIVATION ANALYSIS

S. J. Yeh, *C. L. Tseng, *J."C. Wei Institute of Nuclear Science, •Nuclear Science and Technology Development center National Tsing Hua University, Hsinchu, Taiwan, R.O.C.

Neutron activation analysis (NAA) has been widely accepted as one of the most popular and powerful method for deter­ mination of trace elements in various kinds of materials. However, in the practical work, the concentrations of trace elements under consideration are very often much below the detection limit of NAA. In this case preconcentration process is quite necessary prior to perform the analysis if one wishes to obtain more reliable analytical results. In comply with this approcah considerable efforts have been devoted for the preconcentration studies for NAA in our laboratory and satisfactory results were obtained (1-4). In our previous work the basic aspects of radiochemical separation by adsorption of various ions from aqueous solu­ tion onto hydrous magnesium oxide were studied rather in detail (5). It is the purpose of this work to report a simple but effective procedure to preconcentrate trace elements from aqueous solution by using hydrous magnesium oxide for NAA.

In recent years the public are very much concerned with the fact that the extent of domestic environmental pollution seems to become more and more serious due to the rapid growth in various fields of industry and developments in new technology. In paticular the surface water of a number of large rivers which play very important roles in the lives of local people are polluted rather badly. In order to improve the quality of living standard it is rather important to establish reliable analytical methods so that more effective surveillance can be enforced on pollution control problems. For practical work.low density magnesium oxide was used in this work. It was carefuly selected and its radiochemical impurity was determined by NAA„ It is known that when magnesium oxide is added into water, small portions of it undergo hydrolysis to produce fresh magnesium hydroxide and the pH of the solution changes accordingly. However, the rest of magnesium oxide remains unchanged, and eventually one gets the mixture composed of a small fraction of magnesium hydroxide and .magnesium oxide in a large fraction, which fact helps to speed up the sedimentation of precipitates. Carful examinations showed that' the pH of the hydrous magnesium oxide suspention solution is dependent on the contact time

282 and the ratio of magnesium oxide to the amount of water used. Attempts were made to investigate the feasibility of using hydrous magnesium oxide as preconcentration agent for NAA. A series of solution of synthetic mixtures containing known trace amount of various elements were prepared. Large volume (2~5 liters) of the solutions were taken and their acidities were adjusted to pH=2. 1~2.5 grams of dried magnesium oxide was added and the mixture was stirred for 30 minutes before it was set aside to let the mixture of magnesium oxide and mgnesium hydroxide to sediment to the bottom. The precipi- . tate was separated, and an appropriate aliquot of the precipitate was used for determination of trace elements by NAA using Tsing Hua Open-pool Reactor (THOR). The results are summarized in Table 1. It can be seen clearly from the results that this preconcentration technique is rather reliable. In order to confirm this results another aliquot was analyzed by atomic absorption speetrosccopy(AA) and inductively coupled plasma atomic emission spectrosmetry (ICP-AES), respectively. The results are also shown in Table 1. It is noticed that the agreement on the Analytical results by these three methods are found to be satisfactory. Thus, it my be concluded that preconcentration by using hydrous magnesium cxide from aqueous solution is suitable for NAA, because this process is simple, quick and reliable, you also have advantage of carrying out simultaneous multi- elemental determination by NAA.

References 1. J.M. Lo, J.C. Wei and S.J. Yeh, Anal. Chem. Acta. 91_ 311 (1978). 2. J.M. Lo, J.C. Wei, M.H. Yang and S.J. Yeh, J. Radioanal. Chem. 7_5 571 (1982). 3. S.J. Yeh, J.M. Lo and Y.L. Wang, J. Chinese. Chem. Soc. 3J. 42 (1984). 4. J.M. Lo and S.J. Yeh, ibid. _31 59 (1984) 5. S.J. Yeh, J.M. Lo, C.L. Tseng, J. Radioanal. Nucl. Chem. V2A_ 157 (1988).

283 Element s

o "1 2 o n c 0 a 3

0. 1 — ox o o O o o o >0 0 3 1 1 1 •a 3 o I-- i- I-- I- • I- 3 0 S ~ 3 "1 o o o o o o o o o o o o o o o 0 c 1' 1 o o o o o o o o o O O !-• o o o 3 VO VO VO VO VO VO VO VO VO VO VO O VO VO VO a o •*» *» Ul HCO u ^i ro ro vo ui o o o o o o o o o o VO VO VO VO U VO Ul Ul 1+ > 1 (+ 1+ H- 5 o o !+ o o < ' o o o o o o o o o o ro I-- it.

LI U) Ul

1 1 o o o o o dp 0.09 6 0.05 8 0.09 4 0.09 4 0.09 2 0.09 1 0.09 5 0.09 3 0.09 7 o o O e 1 1 o I-- 3 VO o 1 a Ul I- o o o o o o o o . o • o VO VO VO VO vo ro Ul Ul VO Ov > > H- 1+ H- 1+ 14 > I 1 o o o o O < o o o o c o o o o o to I-- ro ro

oo Ln Ul 1-" Jts. t> 1 1 o o o ' o O ——— — 0.1 0 j 0.098 ! 0.09 6 0.098 i 0.09910.00 1 0.09 8 0.09 7 •"I o o o o o o o o ... 1 e 1 1 I-- I-- I- O 3 1-" )-• O o POIO O O VO ro a

o o o o H o o n o o 1 VO i- VO o 00 VO VO > > H- I4< H- ro o 1 H- .1 o o < o o o o o o o o u> o ^1

i-1 ro 1 o 1 M 1

284 Determination of 13C in Breath Sample by PIGE Zhang Weicheng, Zhang Tianmei, Zeng Wenbing, Lei Xiangguo Institute of Modern Physics, Academia Sinica, P.O.Box 31 Lanzhou

The proton induced Gamma-ray emission(PIGE) method is suitable for analysis of light elements using a low energy accelerator'1'. The purpose of this paper is to report the feasibility and its applicability of PIGE as a conventional method offered by the nuclear reaction 12C(P,7) 13N and 13C (P,7)14N to estimate 13C in breath samples because of using 13C as a tracer in breath test. 13C is nonradioactive, its advantages over 14C are clear.

We bombarded thick samples of human breath, urea, glucose,benzamide, barium carbonate, as well as thick graphite and tank CO2 standards, with proton of 0.6 Mev obtaining from 2 x 1.7 Tandem or 2 x 2 Tandem. Prompt Gamma-ray spectra produced during nuclear reactions with 12C 13C were measured with Nal(Tl)—IBM-Pc data acquisition system'2'. The intensities of the photopeaks of interest were calculated in each of the spectra with the help of the program MMCA-CM8 at IBM-Pc-XT computer. The detector was placed immediately behind the target so as to provide a maximum solid angle. Reactions used, their corresponding resonance energies and prompt 7- rays are 12C(P,7)13N, 0.457 Mev, 2.366 Mev; 13C(P,7)14N, 0.554 Mev. 8.061 Mev respectively'3'. As only thick targets were used, the 0.6 Mev protons could only reach ( by energy degradation in them ) the 457 Kev and 554 Kev and induced resonances nuclear reaction, thus, the intensities of the corresponding 2.366 Mev and 8.061 Mev gamma rays were correlated with the contents of 12C and 13C respectively in samples. 3 Results A total of 114 spectra were obtained. The sample spectra resemble each other and are also similar to the standard. In all spectra the peaks of interest are well defined and free from interferences, thus being quile suitable for count-rate comparisons. 1> Accuracy Classical studies on differences in 13C isotopic abundances.among common natural substances indicate a range of variation of 4.5%'4'. therefore, the accuracy of the present method had to be checked against previous mass spectrometry [ MS ] determination, taken as "true" results for this purpose. The mean 13C per cent abundance was obtained for BaCC>3, by PIGE, with reference to a "ture" graphite standard, and compared with a "ture" results obtained by MS for same BaCC>3 sample. The result is presented in table 1.

285 Table 1. The comparison to determine 13C abundance by MS and PIGE

Method reference standard 13 C abundance in

values BaC03 MS(MAT-251) 1.108 1.084 PIGE 1.108 1.089

The relative accuracy error was only -0.4% in this test.

2> Determination of 13C in breath samples 13C abundance was determined for human breath natural samples, by comparison with the two standards. Each sample was bombarded three suc­ cessive times with about a 0.5 fiA beam of 0.6 Mev protons. Some results are presented in Table 2. Table 2. Precision and Accuracy of 13G Abundance Determinations in Human breath by 0.6 Mev Proton

Sample Standard Average 13C Standard Absolute Abundance Deviation Error* (%) (%) (%) Human breath Graphite 1.17±0.23 19.5 +5.6 (woman) Tank Co2 1.18±0.23 19.6 +6.5 Human breath Graphite 1.04±0.13 12.4 -6.1 (man) Tand Co2 1.01±0.15 14.7 -8.8

*A11 samples had the natural abundance of 13C, that is, 1.108%

The standard deviation indicated above table.2 are taken to represent the precision of these determination. It may be observed that the precision values for breath samples is < 20% and these precision values are independent of the nature of the standard used to determine sample,while the absolute error (accuracy) is generally below these value, as expected, then, if a 25% change is conservatively assumed obserable in 13C abundance, an increase from its natural 1.11% value (average) to 1.39% will be detected. The isotopic abundance for 13C in breath samples were the nature values and, thus, the minimum to be possibly encountered in most stable tracers experiments; they can only increase by administering stable tracers to liv­ ing organisms, with corresponding improvements in counting statistics and, therefore, precision in actual practice. References [1] J. Raisanen, Nucl. Instr. and Meth. B17 (1986) 344. [2] Zeng Wenbing, Zhang Weicheng, Zhang Tianmei, Yang Zhengguo, Institute of Modern Physics, Academia Sinica. Annual Report 1987 P.116 [3] F. Ajzenberg-Selove, Nucl. Phys. A 152 (1970) 1. [4] H. Craig, Geochim. Acta, 3, (1953) 53.

286 MULTIVARIATE STATISTICAL TREATMENT OF PIXE ANALYSIS OF SOHE TRADITIONAL CHINESE MEDICINES

Zhang Xiaofeng And Ma Jianguo (Institute Of High Energy Physics. P.O.Box 2732,Beijing) Jun Fa Qin And Lun Xiao* (Institute Of Nuclear Research, P.O.Box 8204,Shanghai)

Several tonics and nontonics of traditional Chinese medicines were analyzed for their essential trace elements by neutron activationtl]. The results seemed to show that traditional Chinese medicines might be classified by the order of magnitude of their essential trace element contents. 30 kinds of traditional Chinese medicines were analyzed by PIXE [2] for their essential trace elements. The results did not'confirm our previous suggest ion [1]. We now treat the data with multivariate statistical analysis.

Samples were washed, dried and ashed . The ash residue was dissolved in GN IIN03, and lOOppm of Yittrium was added as internal standard. The beam current was in the range of 10-20 nA . Each sample was bombarded by 3.1McV Proton for about 10 min for a total charge of 5-10 uC. According to the traditional Chinese medicine practice,the 30 kinds of traditional Chinese medicines may be classified into 24 tonics and 6 nontonics. We are going to see if we can classify these medicines according to their trace element (Sr.Pb.Zn.Cu.Ni.Fe.Mn.Cr.Ca.K) contents by Multivariate statistical analysis. The data will presented in our full paper.

1.Multi-matrix average test We use multi-matrix average test to see if we can distinguish between the two kinds of medicines,tonic and nontonic . The Wilks statistical quantity A(10,28,l) is calculated, which turns out to be 0.34, At %% confidence level, At(10.28,l)=0.44, which is greater than A(10,28.1). So at the %% confidence level, the two kinds of traditional Chinese medicines are different. And by single variate analysis, we find that the difference between these two kinds is mainly due to their Pb.Zn.Ni ,Cr, Cu and K contents.

2. Nonlinor Mapping Algorithm(NI.M) The NLM method [3] is based on a nonlinear-point projecting of N I.- dimensional vectors from L-dimensional measurement space to a two-dimensional space preserving the inherent natural structure of the data. This is achieved by fitting N points in the two-dimensional space so that their interpoint distances approximate the corresponding interpoint distances in the I. space. Let the distance between the vectors Xi and Xj in the L-dimensional space be defined by the distance measure D7j, and the distance between the corres­ ponding vectors Yi and Yj in the two-dimensional 2-space be defined by DIJ. The mapping error E which represents how well the present configuration of points in the two-dimensional space fits the N poinLs in the original L- dimonsional space. The two-dimensional space configuration is adjusted so as to decrease this error, and a steepest descent procedure is used to search for a minimum of E. E is calculated by: i On lcnve Troi Institute or AUmic Energy, P.O.Box 27S, Beijing

287 (Pi-M/Zf M Ve use Euclidean distance, and in case of voiding the influence of different order of data magnitude ,we normalized the data before calculation. The HLM mapping of these traditional Chinese medicines is shorn in Fig.l ( + represents nontonics). The mapping space can be divided into three regions by circles in fig. First circle contains 19 tonics and 1 nontonic, the second circle contains 3 tonics and 2 nontonics. The rest 2 tonics and 3 nontonics are belong to_ the third region. It gives us a clear view that the 30 traditional Chinese medicines are almost separable ,and the tonic medicines are relatively clustered in one region and non-tonic group are scattered.

3. Q-mode cluster analysis Q-roode factor group method was also applied to those date with Euclidean distance and normalization . The result is shown in Fig.2. By a line d=G in Fig2, The 30 kinds of medicines can be divided into two groups: group (1,4,15, 10.16.8,11.12,17,5,7,6.10,9,13.18,20,3,22.28) and group (21.25,20,28,27). The residual 2,30,23,14,24 can not be grouped. Comparing to Figl we found that the two results are almost the the same, but Fig2does not present a good "view" as that of Figl. So the NLM method seems to provide an easy and clear way to deal with multivariate data.

5.3

3.3

.4 1.7

-«.2

-2.B

-3.J Xi 31 ^ll 'tJ 71 tl I nIJl7il$.iiJi?5 76ii>9'»>?J«.,.>i!j;'|i54v7Mif-'f

Figl. NI.H result of Chinese medicines Fig2. Q-mode cluster result

Reference 1. L.Xiao, Y.II.Zhang, Y.G.Liu & J.F.Qin, "IHM of Essential Trace Elements in Some Traditional Chinese Medicines", presented at the 2nd International Conference on Nuclear and Radiochemistry. Brighton , UK, 11-15 July,1988. 2. L.Xiao et al "PIXE Analysis of Essential Elements in some Traditional Ch inese Medicines', Presented at the International Conference on Nuclear Analytic Heth. in the Life Science, Gaithersburg, HIST, II.S.A.Apr.17-21,1989. 3. John.W.Sammon, JR. "A Nonlinear Mapping for Data Structure Analysis" IEEE. Trans. On Computers. Vol.cl8. Ho.5. May 19G9.

288 DETERMINATION OF TRACE ELEMENTS IN SUBCELLULAR FRACTIONS OF FIUMAN LIVER BY INAA

Jian Zheng and Gui Sun Zhuang Shanghai Institute of Nuclear Research, Academic Sinica P. 0. Box 8204, Shanghai, China

An increasing numt>er of observations show that trace elements play an important role in intracellular metabolic processes. It is now knou-n that trace elements are mainly attached to proteins in biological materials. Although it is beyond question that a better understanding of the biological effects of trace elements can be achieved primarily by the isolation and biochemical characteri­ sation of metalloprotein, i.e. specific metal-binding proteins, an important, roie must be assigned also to the quantitative distri­ bution of trace elements in cell organelless.

This work is intended to investigate the distribution of trace elements in subcellular fractions of normal human liver. For this purpose, a combination of differential centrifugation and INAA methods has been established. Samples of human liver were homogenized in a buffer containing sucrose and HEPES, and the homogeneate separated into nuclei, mitochondrial, lysosomal, microsomal and cytosol fractions by successive differential centrifligation. Concentrations of up to 20 elements have been measured in these fractions using the INAA methods. Two certified reference materials were analyzed for evaluating the accuracy of the INNA methods, and our results were observed to agree within +5 - 10% of the certified values. Protein content of subcellular fractions was determined by the method of protein-dye binding.

289 The Se levels in different, fractions lias bo^n found to vary between 0.24 and 1.24 ppm. It is mainly concentrated in the nuclei and mitochordrial fractions. It is worthy to be noted that Se. Zn and. Mn have similar distribution in subcellular fractions, and show a same variation. Iron is present in relatively large amounts in all subcellular fractions, in particular microsomal. fraction. Concentration of Cr has been found to vary significantly from one fraction to the other with the highest percentage in the mi!ochondrial fraction. Copper concentrated in the nuclei and mitochondrial fractions. Toxic element Hg shows a same high concentration in mitochondrial and cytosol fractions. Manganese is mostly concentration in mitochondrial fraction while I?.b is largely present in nuclei. The distribution pattern in all subcellular fractions of human liver follows the following' order: Fe>Zn>Cu.

Further- resea)~ch will focus attention on making use of bioanaly.tii-al technique-? and T\:AA to study metalloi.irot.eins and l»rote in-bound trace element? in humeri liver.

290 PIXE ANALYSIS OF CHEMICAL COMPOSITION OF GRAPHITE PHASE IN CAST IRON

Zhong Ming, Feng Songlin, Liu Nianqing, Ren Minqin, Zhang Xiaofeng and Yan Lingna Institute of High Energy Physics,Academia Sinica Wang Yu and Han Qiyong Beijing University of Science and Technology

It has been known that the trace elements have an effect on nodulizing of graphite in cast iron. Although some trace elements in cast iron were studied by researchist, the knowledge of graphite phase in cast iron is rare. However , It is probably more significant to study the trace elements in graphite phase . The available data are not in agreement with each other. Obviously, it is important to analyze the trace elements in graphite phase for nodulizing theory and production of the nodular cast iron.The contents of the trace elements are very high in cost iron produced by quiet a few factories in China. We measured the contents of Al, Si, P, S, CI, Ca, Ti, V, Cr, Mn, Fe, Ni, On, Zn and As of graphite phase in nodular cast iron, and mainly studied the dependence of As and Ti on graphite nodulizing.

The iron samples from three places (Benxi, Jinan and Xingtai) in China were collected. We used pig iron made in Benxi, which now has the lowest contents of the trace elements in all the samples, for investigating the dependence of As and Ti on nodulizing of graphite. An electrolytic technique known as "speed" was used to extract the graphite from the samples of the nodular cast iron. There are many impurities such as MnS, CaO, TiC, TiN, VC, Al, FeO etc. in the extracted matter, except for pure graphite phase. These impurities were removed from graphite phase by using solubilization of them in HC1 or HC1+H. In order to identify purity of graphite, we examined effect by means of ICP, PIXE and X-ray diffraction and obtained solubiliration optimum time of about one hour.

PIXE analysis of the trace elements of graphite phase was carried out at the PIXE facility of Institute of High Energy Physics, Beijing. In order to avoid the difficulty of preparation of thin graphite target and escaping of low melting point elements such as S. As during processing graphite for preparing thin target, we used the thick target for PIXE analysis, After having fully mixed the powders of graphite with a little boric acid ( about 10 percent of target weight), they were pressed into a disc thick target with 10 mm in diameter and about 2 mm in thickness by

291 a hydraulic press. We calibrated the system of the PIXE analysis by means of both the thick standard and thin standard with calculated correction. Both the calibrations are in a good agreement. We measured part of the trace elements of one graphite phase by using ICP to check .

A typical PIXE spectrum of the graphite sample is shown in figure 1. The exper­ imental results of the graphite phase samples show:

1. Our separated technique of electrolyte and thick target analysis for graphite phase are feasible. 2. The contents of As and Ti in graphite phase are correlated with anti-nodulizing. They mainly exists in the nodular cast iron as form of impurity phase. The concentration in graphite phase is less than that one in other phase. A change of small amount of the trace elements in graphite phase is able to affect the nodulizing. 3. The contents of the trace elements of graphite phase in cast iron from three places correspond with nodulizing state and mechanical properties of the cast iron.

COUNTS/Channel Fe I

10653^ ca As j Si CI I m, 1816 i ). i .- Tf Cu Hi Zn 310i-

53 ••

60 120 180 240 300 360 420 480 520 Channel Number

rig- 1

292 RADIOCHEMICAL SEPARATION OF 199T1 FROM THE Au TARGET BOMBARDED WITH a- PARTICLES

Zhou Dehai Institute of Nuclear Science and Technology, Sichuan university Chengdu, China

199T1 can be produced through the nuclear reaction 197Au(a,2n)199Tl. As shown by its physico-chemical properties and the animal experiments, the radioisotope has an advantage over 201T1, and as an agent for imaging myocardial perfusion it is possible for it to replace the latter.

Experiments and discussion 1. The Influence of the Acidity on fchaAdsorptio n Efficiency of the Ani­ on resin for Au(III), Tl(III) and TL(I) 15 portions of the Type 201 anion resin having grade size of 80-100 me­ shes and weighing 200 mg each were put into the scaled extractors and were devided into 3 groups, to which was then added Au(III), Tl(III) or T1(I) by 100 yg for each extractor and then 4ml of HC1 of different con­ centration in the same way. The extractors were shaked 20 min., and the contents of the elements in the clarified solution were determined. The best adsorption efficiency was obtained when the concentration of HC1 was 4-6 mol/1. The sequence of the adsorption efficiency of the resin was Au(III)>Tl(III)>Tl(I). 2. The Relation Between Eluant Concentration and Elution Efficiency The treated resin put wetly into a chromatographic column #10 and having height of 150 mn was ballanced with 4 mol/1 HC1 to which were t :en added Au(III) and T1(I) by 200 yg each. The Tl(I) and Au(III) were eluted by

N2H^-Hz0 of different concentration and 2 mol/1 HC1-H2NCSNH2 with the flow rate of 0.5 ml/sec, and collected by section,.and the contents of the elements in the collected solutions were determined. The results have shown that (I) the elution efficiency increased with the concentra­ tion of the eluants and (2) the best elution efficiency for T1(I) and Au(III) was 92.5% and 95.6%, respectively. 3. Separation of Au(III) and T1(I)

293 The solutions of Au(III) and 11(I) taken by 200 yg each were mixed and put into the resin column. The Tld) and Au(III) were eluted by 85%

N2H4-H20 and 2 mol/l HCl-5% H2NCSNH2, respectively with the flow rate of 0.2 ml/sec and collected by section. The contents of the elements in the collected solutions were determined by atomic absorption spectroscopy. The recovery ratios for T1(I) and Au(III) were 98.5% and 99.5%, respec­ tively. 4. Radiochemical Separation of 199T1 A disk

After removing the most Au and all of the N03~ ions, the solution has been transformed into a HC1 system, which was added to the resin column. The 199T1 and Au(III) were separately eluted. 100 yl were taken from the collected solution of 199T1 to carry out the Y-spectrometry. The radio­ activity of 199T1 and 200T1 was 3x10s Bq and 8xlQ2 Bq, respectively. The radioactivity of 200T1 accounted for 0.27% of the overall radioactivity. The yild of 199T1 was 500 yCi/yA-h. The contents of the elements in 1 ml of the injection (specific radioactivity was 2 mCi/ml) were determined with a plasma spectrography. The contents were: 0.330 yg/ml for Au, 0.114 yg/ml for Tl and 1.91 yg/ml for Fe. 5. The Measurement of the Chemical Valence State of 199T1

Na2HP0i»'12H20:CH3C0CH3=l:9 was used as the developer. The automatic de­ termination of the radioactivity was carried out by automatic chromato­ graphic radioscanning. Rf=0, which is in agreement with the ref. 2.

[1] Yuichiro Nagame et al., Int. J. Appl. Radiat. Isotopes 30, 669 (1979) [2] Bonaridi, Radiochem. Radioanal. Letters 42/1/35-44 (1980)

294 PRELIMINARY STUDY OP TRACE ELEMENTS IN HUMAN BRAIN TUKOUR TISSUES BY INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS

Zhuang Guisun, Wang Yinson, Tan Mingguang, Zhi Min, Wang Yongjia Shanghai Institute of Nuclear Research, Academia Sinica Zhang Pulin Departments of Pathology and Neurology, Hua Shan Hospital, Shanghai, China

Cancer is a multifactor complex of disease. Environmental carcino­ gens such as radioation, viruses and chemicals play important roles in the initication, progression and activation of tumours. Trace elements have "been implicated as neurotoxic factor in a number of human brain disorders. However, the distribution of trace elements in brain tumours is little known yet. INAA procedures for determination of at least 17 elements in human internal tissues have been used in our laboratory. The specimens of maligant brain tumours of 15 male patients (astrocytomas grade I-III) and normal human brain tissues of 23 male age matched autopsies have been collected from Shanghai area.

The freeze drying and brittle fracture technique arc used for preparation of all the samples.Typically, 100 mg of sample are used both for short and long thermal neutron reactor irradiations. Detection of some short-lived and long-lived radioisotops in the samples are achieved by pneumatic-rabbit system at SLOWPOKE reactor 11 —2 —1 with a thermal neutron flux density of 6-8 X 10 n.cm sec and 13 -2 -1 swimming type reactor with a that of 1 X 10 n. cm sec , respectively. The analytical reliability has been checked with three biological standard reference materials: bovine liver ( NBS SRM 1577a), horse kidney (IAEA H 8), and tomato leave (NBS SRM 1573)

The analytical results show that the concentration of Br, CI, Na,

K, Mn, Pe, Cu, Zn, Set and Rb in normal brain tissues are. in close to the literature values presented by Tapper and Ehmann ( 1,2 )

295 The contents of Co and Sc are presented at ng/g dry weight level. Compared with the normal brain tissues as controls, the results show an elevation of Fe, Ca, Zn, Cu, Se, Mn, Co, So, and Br concen­ trations in the human "brain tumour tissues ( P values less than 0.001 ). The concentration of Rb and K in the cancerous tissues are decreased, while the elements of CI, S, and Mg levels have not any significant difference. The low levels of K and Rb may be associat­ ed with disturbances of fluid retation or excretion. The essential elements of Pe and Zn level are high in the cancerous tissues that may be essential for cell growth and withdraw sufficient amounts of the elements to cause systematic Pe and Zn deficit for cancer patients.

Table 1 The concentrations of element in normal human brain and maligant human brain tumours (mean values and relative standard deviation x ± s jug / g dry material )

Element Normal Human Brain Element Normal Human Brain Brain Tumour Brain Tumour

Se 0.569 ±0.17 1.12*0.22 K 13100*1500 4900*2240 CI 6420±831 4640±2110 Hg 0.158±0.087 0.237*0.22 Mn 1.16*0.43 3.59*2.40 Cr 0.80±0.53 0.58-6.56 Na 6l64±733 6l65±2394 Sc 0.002*0.0001 0.007±0.006 Cu 25.8i 6.9 38.5*22.5 Rb 22.2±7.0 11.2 ± 6.3 S 9830±3700 9470*3970 Pe 224*34.6 539*402 Br 3.27+1.16 7.48±3.13 Zn 41.3±5.6l 8l.9±20.6 Mg 700±102 '677±177 Co 0.035*0.006 0.062*0.008 Ca 241^152 1920*2040 (l)U.A.S.Tapper,et al.,Nucl Inst & Meth in Fhy Res, B22 (1987) 176-178 (2)W.D.Ehmann, et al,, Biol Trace Elem Res, 13 (1987) 19-33

296 STUDY ON EVOLUTION OF GRANlTjyPEGMATITE IN PEGMATITIC PROCESS BY MEANS OF NAA

Ding Xixiang, |Chen Baoguan] Chinese Institute of Atomic Energy P.CBox 275, Beijing, China Yang Yueqing Institute of Mineral Deposit, Chinese Academy of Geology

REE distribution characteristics in potash felclspar samples of different occurrences from four types of granite-pegmatite were studied by means of NAA. Samples were taken from Sinian Period metamorphic rocks between two granites in Southern China. Both pegmatite and granite were formed during later Hercynian tectonic cycle, and the flegmatite and metamorphic rocks have obvious intrusive contact relation. The four kinds of pegmatite are products of a unified pegmatitic process at different stages.

Ground samples of 50 mg each together with chemical standards and international reference materials were irradiated at HWRR of CIAE WITH 13 -2 -1 a thermal neutron flux of 5*10 n cm sec for 48hr. Radiochemical sparation was carried out by using HEH (ERP) extraction chromatography (80—100 mesh). The procedure is simple, fast and specific, with REE recoveries greater than 95$.

The results show that although potash feldspar is one of the most abundant rocks, it is not the major carrier of REE. The ratios of LREE/ HREE in the potash feldspar samples analyzed are from 2.4 to 572. The CI chondrite normalized REE contents for all the potash feldspar samples show a high in left-low in the right pattern, similar to those for their mother rocks.

297 A positive anomaly of Eu was shown in most potash feldspar samples* while a small Eu negative anomaly with

A comparison among different groups of samples shows that REE contents in granite potash feldspar are obviously higher than those in potash feldspar from pegmatitic segregated materials of granite. The later the pegmatitic process, the lower the REE contents in both potash feldspars and their mother rocks. For s. certain vein system,potash feldspar formed later contain less REE than those formed earlier. The same trend exists for (La/Tb) and LREE / HREE in different types of potash feldspar. The variations in (La/Sm) and

In summary, it has been found that the contents of SEE in potash feldspars are proportional to those in corresponding mother rocks. This allows us to obtain some information on the evolution involving pegmatitic process by study REE contents in potash feldspar easily sampled from pegmatite.

298 SAMPO 90: An Accurate and Versatile Tool for the Gamma Speclroscopisl

Edward G. Fisher Don.q Nai-Sheng Canberra Industries Inc. Canberra Packard Service Centre One SLate Street* Meriden No. 57 Xi Si Dong Da Jie Connecticut 06450 U.S.A. Beijing, 100034, P.R.CHINA

GAMMA 90 is a research-grade Gamma Spectroscopy software package that is also highly capable for high-volume sample counting labs. It provides ex­ ceptional analysis results on all HPGe spectra, even those with complex uultipU'ts[Fig.U. SAMPO 90 is based on the sophisticated SAMPO analysis algorithms and techniques[Fig. 2), the standard for gamma-ray spectroscopy for over 20 years. For the first time, SAMPO 90 brings these capabilities to both the research and volume sample counting environments.

The mine SAMP090 is derived from its early predecessor, SAMPO. originally developed in 1969 for the mainframe computers at Lawrence Berkeley Labor­ atory and Europe's CERN. SAMPO has been acknowledged by the IAEA as being one of the best gamma spectroscopy packages available.

Far most routine sample coon ting, SAMPO.90's automatic mode provides han- ds-off counting procedures. For those occasional samples where routine a- nalysis isn't good enough. SAMPO 90 gives the spectroscopist the ability to interact with the analysis process via an interactive peak fit functi- on[Fig.3.1J. In this manner, the experienced spectroscopist can apply his judgement with sound statiscal results[Fig.5, 6]. For the researcher, this feature makes SAMPO 90 is aji essential tool. With interactive shape cali­ bration, linear and non-linear peak fit, and interactive display manipu­ lation, SAMP090 is unsurpassed in its flexibility in performing complex gamma analysis.

For the NAA researcher/ the interactive peak fit is an extremely valuable tool, due to the highly complex nature of the resultant spectra. However, for those applications requiring repetitive, automated operation, SAMPO 90 is compatible with the 'BATCH' mode of several commercially-available Multichannel Analyzer system, enabling 'production' style analyses with little or no intervention from the operator. This feature, relatively new to the SAMPO environment, broadens the package's applicability from one . of pure research to more general experiments.

In this paper, the features and mathematical bases of SAMPO 90 are revie­ wed, and comparisons are made of the peak-detection capability of SAMPO 90 to other commercially available packages from Canberra and Nuclear Data. The ability to detect and separate multiplets under various separations is examined. SAMPO 90 is now fully compatible with CANBERRA-ND's compact, co­ st-effective System 100 and AccuSpec Personal Computer Multichannel Analy­ zers.

299 P?S5?BIB111I

Figure 1 - Full; Speaxum Display. Rgure 2 - MuRiplet Deconvolution Screen Showing Residual Graphs.

Figure3 - Initial: Ficr High ResidualsShcw Figure 4 - SAWPO 90 Positions the Cursor on Possible Passihie IWultipiet. Location of Additional Peak.

Figure 5 -PeafcistaraeiisrefvActerexi. Racataiiaadl Figure 6 - Interactive Addition of a Third PeaK ResidtislisShoar ImptoxecS Fit. Further Reduces Residuals.

300 DETERMINATION OF ALUMINIUM AND SILICON IN ZEO­ LITES BY PIXE

Max Peisach; C.A. Pineda National Accelerator Centre P 0 Box 72, FAURE, 7131 South Africa.

A.E. Pillay; T. Themistocleous Chemistry Department, University of the Witwatersrand JOHANNESBURG, South Africa.

Zeolites are crystalline aluminosilicates which have the ability to pro­ mote a large number of acid-catalysed reactions. The acid activity of zeolites depends on the presence of trivalent ions such as Al3+ in the zeolites framework of shared Si04 tetrahedra. Without their presence, crystalline silicas have no acid activity. It was shown that their acidity increases with increasing Si/Al ratio until it reaches a maximum and then declines again. The rate of deactivation of zeolite catalysts was dependent on the Si/Al ratio. This ratio also affects some of their physical properties such as thermal and hydrothermal stability and some of their chemical properties such as hydrophobic- ity and stability towards acid solutions. It is therefore clear that the determination of Si/Al ratio of zeolite catalysts is of extreme importance.

Although neutron activation analysis is a widely-used method for ele­ mental analysis, this method is open to error when adjacent elements are analysed. Since the same nuclear reaction product is formed by the (n,7) reaction on element Z, by the (n,p) reactions on element

301' (Z+l) and by the (n,o;) reactions on element (Z+2), the presence of element (Z+l) and/or (Z+2) could interfere with the determiration of element Z. In the case of zeolites, where Al and Si are to be deter­ mined, through the measurement of the activities of 28A1 and 31Si, serious interference may be encountered if P and S are also present in the sample, from 31P(n,a)28Al, 31S(n,p)31Si and 34S(n,7)31Si. ?or routine analysis, therefore, an alternative method was preferred. The prompt emission of X-rays under proton bombardment has already been shown to be suited to the routine determination of Si/Al ratios

The present investigation compares the methods of X-ray fluores­ cence (XRF) with that of Particle-Induced X-ray Emission (PIXE). Using 1.0 MeV protons on thick targets of zeolite pellets, aluminium and silicon were determined by PIXE. Results were compared with XRF data. The relative root mean square error was 3.7% and the results of the two methods agreed with a correlation factor of 0.991. PIXE analysis can be carried out on very small samples, while sample preparation involves minimal handling.

[1] A.E. Pillay, M. Peisach, R. Carblissen and C.A. Pineda, Nucl. Instrum. Methods B4£ (1990) 333.

302 PROMPT GAMMA NEUTRON ACTIVATION ANALYSIS

OF COAL AND COPPER ORE SAMPLES A.A.Soltanieh,A.Pazirandeh,N.Rahimian & M.Salehi Neutron Physics Section,Nuclear Research Center Atomic Energy Organization of Iran P.O.Box 11365-8486,Tehran,Iran

ABSTRACT

The increasing demand for mineral and energy resources requires advanced efficient analytical techniques. During the last three decades the atomic, molecular and nuclear techniques have been used as efficient, fast and reliable tools for elemental analysis with high accuracy.

In addition to the existing atomic and molecular analytical system being routinely used in Iran, prompt gamma neutron activation analysis(PGNAA) is established at the Nuclear Research Center(NRC) of the AEOI. The NRC-PGNAA facility is composed of a neutron colli­ mator being installed at the 6-inch beam of the 5 MW swimming pool MTR Research Reactor, target room, beam catcher, and gamma spectro­ scopy system.A Ge(Li) detector protected by a Lithium polyethelene sheet surrounded by four Nal(Tl) detectors for gamma-gamma coinci­ dence purpose incorporated with a multichannel analyzer, a semi- computerized data acquisation system, is used in both fundamental and applied projects.

This paper would however deals with the applications of PGNAA in the analysis of Iranian copper and coal mineral samples. The ul­ timate goal of this project is the In-Situ exploration of mineral resources by PGNAA using neutron sources preferably Cf-252 and a a mobile laboratory.

In this project coal and copper samples contained in a wooden box of 50x50x50 cm were irradiated by a well-collimated neutron beam ,2cm in diameter, as shown in Fig(l). Main elements identified in the spectrum in Fig(2) of the coal samples are S,Si,C,Mn,Fe,La and in the copper samples are Cu,Cr,Si,V,Na,and Fe. Comparison is also made with the results received from PIXIE, delayed gamma neutron activation analysis(NAA), and atomic absorption techniques.

303 NUCLEAR RESEARCH CENTER REACTOR'S COLLIMATOR

SiS'.VEiy; fiuan^i, H-yn/?i £Alr ^.JM* 'Icm M-rrn y nJd^w^ '.fuMt CUc rr.M'^rM

Section AA

304 NEUTRON ACTIVATION ANALYSIS IN MNSR

Vang Ke Institute of Atomic Energy, Beijing, China P.O.Box 275-(75) Beijing, China- Li Shenzhi Center of Phtsical & Chemical Analysis, Beijing, China P.O.Box 8106 Beijing, China

The Miniature Neutron Source Roactor ( MNSR ) was first built in March, 1984 at the Institute of Atomic Energy, Beijing, China. Because it is put into operation. It is possibility to popularize the technique of neutron activition analysis in China.

As a matter of fact, the MNSR is used as a neutron source for neutron activation analyses. It has own characteristics and following featuresi

(A) The MNSR has an inherent safety, and has a lower exposure rate to the environment.

(B) The operation of the MNSR is very easy, the irradiation can begin 15 minutes later after the reactor startup.

(C) The neutron flux is stable during the operation.

(D) The MNSR can provide neutron flux from 10ao to 1012 n/cm2.s, thus an optimum conditon of NAA work might be chosen.

(E) The temperature in the irradiation site is under 50° C even the reactor is operation at its full power level. Thus the samples containing water or bilofical samples can be irradiated in the MNSR without vaporization.

305 . (F) It; is used for the CNAA ( circulate Neutron Act i vat in Analysis ).

Since 1984, a large quantity of samples have been analyzed using the MNSR. They concern with many fields such as geology, environmental science, biology, medicine, food nourishing science, materials science, etc-.- . The various samples areJrock, mineral, soil, water, dust, coal ash, plant, hair, organism, blood, industrial products, crops, and so on.

On top of the samples, we choose neutron flux, irradiation time, cooling time and mlasurement time as follows.

1. For the element with half 1 ices of a few seconds of more- such as zoF> 77rose etc... . yr 1 xlOari--l xl0lsn/cm3.s 1: .i 20-60 seconds tei <^3 seconds

trr.' 30-60 seconds Where to is the counting time-

2. For the elements with half lives of a few minuts such as ^Mg.^Cu, ZSA1, 12aI, 3SC1, aoBr etc... . jf lxlOaa~lxl012n/cma.s ti 2-10 minutes td 1-20 minutes t<- 5-10 minutes

3- For the elements with half lives more than hours such as ^As.^Zn, asaAu, asaSra etc.. - . jf 5xl0,a-l xl012n/cmp-.s ti >2 hours tcj > 3 days

tCT >15 minutes

306 DETERMINATION OF. 30 ELEMENTS IN SEDIMENTARY SAMPLES BY INAA WITH MNSR REACTOR

ZHANG HEIHUA, CAO CHUANRU Lab of Shandong Bureau of Geology and Minerai Resources 52,Lishan Road Jinan,Shandong P.R.C.

An routine method of determination of 30 eleaents in sedimentary samples has been developed. The conditions allow rapid multielement analysis with short sample turn—round time which is very . useful for the geocheaical exploration.continual measurements have been taken once every day during the period from 3th day to 7th day after irradiation, precision and approximate detection limit have been evaluated. A consideration vtas given to optimum detection limit which has something to do with optimum decay time for elements of Sc Fe Rb. For 9-hour-irradiated samples, the relative standard deviayion is less than 5% for La Sc As Sb Na !» Gd Sm, \W for element Th U Yb Te Rb K Fe, 15M for Ho Ce Ga La Br, 20JW for Eu Cs. Hg Mn Ca Dy 7i V In and Al are determined by 2-min-irradiation.

307 . DETERMINATION OF IMPURITIES IN HIGH PURITY SILICON BY INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS

K. S. Park, N. B. Kim, H. J. Woo, D. K. Kim, J. K. Kim and H. W. Choi Korea Institute of Energy and Resources, 71-2, Jang-dong, Youseong-gu, Daejeon, 302-343, Korea

Trace impurities may be one of the sources changing the mechanical and. electrical properties of semi-conductor grade silicon and, therefore, should be strictly restricted. Neutron activation analysis is very powerful for determining the trace amount of impurities in pure silicon because of its characteristics, especially non-contamination by environment during experimental procedure.[1,2] Impurities in semi-conductor grade silicon have been analyzed. The radial distribution of dopant and impurities, and the' effect of de-contamination has been also investigated.

About two grams of each sample was collected from poly and single crystals. The p-type and n-type wafers were divided into three'parts; center, middle and outer parts. Two grams of each part of wafers was taken as the samples. The samples were washed with trichloroethylene, acetone and deionized water, sequentially, and etched with the mixture of concentrated nitric and hydrofluoric acids. The sample was irradiated at TRIGA Mark III reactor for sixty hours, with two comparators of gold and cobalt. After two days cooling, the irradiated sample was washed again with the same procedure as above, and the activity was counted by HPGe detector. And then the sample was counted again after etching with the same procedure as above. After 2 weeks cooling, the activity was counted for determining the long-lived radioisotopes. The peak identification and activity determination of

308 each nuclide "in the spectra obtained above were done by the program of PIAD(Peak Identification and Activity Determination)[3], and then the content of each element was calculated by the single comparator method using two comparators[4].

Twenty impurity elements of Au.Br, As, W, Cr, Co, Na, Eu, La, Sc, Zn, U, Th, Hf, Fe, Sb, Ag, Ce, Tb and Ta have been analyzed 1n all the samples except the n-type wafer. • The n-type wafer contains dopant of antimony of which content has been determined as about 170 ppm, and the activity of antimony hinder finding peaks of other elements in the spectrum. The highest content is found on the element of Iron 1n the p-type wafer as 29 ppb, and the lowest one on the element of gold 1n the single crystal as 0.08 ppt. The effect of the de-contam1nation on surface can be observed clearly by comparing the two analytical results which were obtained by the procedures Including and not including post-etching. Contents of some elements after post-etching are found to be greatly decreased at the rate of about one hundredth for the contents before etching. From the results for the radial distribution of impurities and dopant, 1t can be concluded that most of all the impurities does not have considerable changes in the contents but in n-type wafer, the content of dopant, Sb, was about 10 percents higher in center part than in outer part.

[1] K. Fuginaga and K. Kudo, J. Radioanal. Chem., 52 (1979) 411. [2] H. L. bottger, S. Niese, et al., J. Radioanal. Nucl. Chem., 130 (1989) 417. [3] N. B. Kim, Y, S. Kim, J. J. Kim and K. S. Park, J. Radioanal. and Nuclear Chem., 125 (1988) 403. [4] N. B. Kim, K. S. Park and H. I. Bak, J. Korean Nuclear Soc, 18 (1986) 85.

309 A STUDY ON KOREAN ANTHRACITE BY INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS

K. S. Park, N. B. Kim, H. J. Woo, W. Hong and S. K. Chun Korea Institute of Energy and Resources, 71-2, Jang-dong, Youseong-gu, Daejeon, 302-343, Korea

Coal is still one of the most important fuels in Korea as s»ore than one third of total consumption of fuels. Most of coals produced in Korea is anthracite. As coal contains many trace elements, coal combustion is at present under scrutiny as potential source of pollution. It is important to prepare reliable analytical methods which can monitor the inorganic constituents in coals. Since instrumental neutron activation analysis method does not need sample decomposition, this is a particularly attractive feature in coal analysis.

Five anthracite samples were collected from each of the five seams of Samcheok coal-field, which evolved at Permian geological period in palaric environmental circumstance. And twelve anthracite samples were collected from thirty seams of Chungnam coal-field, which evolved at Jurassic period in lacustrine circumstance. Each of these seventeen samples was irradiated at the rotary specimen rack of TRIGA Mark III reactor for 20 hours with two comparators of gold and cobalt. The activity of the sample was counted two times by a 70 cc HPGe detector coupled with 4096 channel analyzer after 4 days cooling and one month cooling. The peak identification and activity determination of each nuclide in the two spectra were done by the program of PIAD(Peak Identification and Activity Determination)[1], and then the content of each element was calculated by the single comparator method using two comparators of gold and cobalt[2].

310 Thirty one elements(Sm, U, Br, As, W, Ga, Na, K, Pr, La, Ce, Yb, Lu, Se, Th, Cr, Ba, Hf, Sr, Nd, Zr, Cs, Tb, Sc, Rb, Fe, Zn, Ta, Co, Eu and Sb) have been analyzed. The mean values and ranges of the concentrations of the elements have been calculated for Permian and Jurassic anthracites, respectively. These ranges are similar with those of other countries(China[3], U.S.A.[4], Japan [5], Australia[5] and Turkey[6]), but higher for W, K, La, Th and Rb in Jurassic anthracites. Compared with mean values of Jurassic anthracites, those of Permiam anthracites tend to be higher in many elements, but similar in U, Ga, Yb, Lu, Tb and Sc, and lower in Se, Sr, Fe and Zn. The ratio of the concentrations of 9 rare-earth elements(La, Ce, Pr, Nd, Sm, Eu,. Sb, Yb and Lu) in two kinds of anthracite increase steadily from 0.33 of La to 1.3 of Lu as the atomic number increases.

Samcheok coal-field have five seams. The upper 4 seams evolved at the Permian period and the lowest one evolved at Carboniferous period(a little older period). In these Samcheok anthracites, several elements, such as W, Ga, Sr, Zr and Zn, are present in greater concentration in upper 4 seams than in the lowest seam. Otherwise, some elements, such as Se, Nd and Fe, are present vice versa.

[1] N. B. Kim, Y. S. Kim, J. K. Kim and K. S. Park, J. Radioanal. and Nuclear Chem., 125 (1988) 403. [2] N. B. Kim, K. S. Park and H. I. Bak, J. Korean Nuclear Soc., 18 (1986) 85. [3] B. R. Chen, Q. F. Qian, et.al., MTAA 7th International Conference, 2 (1986) 1199. [4] J. J. Rowe and E. Steinnes, J. Radioanal. Chem., 37 (1977) 849. [5] S. Okada, et.al., Bunseki Kagaku, 34 (1985) 217. [6] S. f. Ayanoglu and G. Gunduz, J. Radioanal. Chem., 43 (1978) 155.

311 Using Library-Directed Analysis for Singlet and Multiplct Peaks R.Seymour,J.Cox, Norman A. Wulvenor and Meng Boniar

EG&.C Instruments, 100 Midland Road, Oak Rid^c, TN 37831-0395

Introduction Library-directed analysis for high-resolution gamma-ray spectra was developed by Gunnick and Niday1 in their GAMANAL program. The concept was adopted commercially by EG&G ORTEC.

Library-directed analysis uses a gamma-ray library to locate peak energies in A spectrum, pie background and channel limits of integration are then determined, yielding accurate net area results over a wide range of data conditions. Identification of radionuclides is straightforward beuiu.se peaks are already identified by the library'; their existence is then used to validate the presence oj a radionuclide.

The library method contrasts to peak-search-directed analysis. In 19fi7, Mariscottr published un algorithm for locating peaks in high-resolution gamma-ray spectra by testing the second derivative of the gross count data. The data are first smoothed to reduce random variations in the data. Second derivative methods locate a minima, which corresponds to the centroid of a photopeak. The located peaks are then matched to a library to permit nuclide identification. These results are finally used to calculate the activity of the radionuclide.

Description Each method has advantages and drawbacks. The peak search is based upon the data meeting specific criteria used by the search algorithm. These criteria may not all be met by certain data. For example, the data are first smoothed, depending upon the number of channels used in the smooth, a very small peak may be washed out. A small peak next to a large peak also may be missed because of the number of channels used. As gamma-ray photopeaks widen with increasing energy, it is impossible to select a single value which works equally weil with narrow low-energy peaks and wide high-energy peaks. Other conditions can also result in a peak search missing a peak. If a peak is not found, then the radionuclide will not be identified, even if present.

312 Peak searches do find peaks even if the nuclide is not present in a gammo-ray library, ensuring that even an unanticipated nuclide is not missed. Conversely, a library-directed method key disadvantage is that it the radionuclide is not put in the library, it cannot he identified, nor would the peak be reported even il it had a very large net area.

Each method has limitations in deconvolution r>f multiplels, the unfolding of an energy region with two or more overlapping peaks. Peak-search-directcd analysis uses criteria of the peak search to identify the centroids of peaks within a multiplet and uses these ccntroids to calculate each component's net area counts. Identification of the components of deconvolution using the smoothed transformed data is limited to peaks with energy separation of about 1 full width half maximum (FWHM). More complex regions may also contain minor unidentified peaks that can significantly affect the net areas or tiie other components.

Library-directed methods are based upon the library used. A very large library may contain many gamma- ray peaks. Unless these peaks are qualified, the deconvolution results may be degraded. Conversely, radionuclides not included in the library cannot be used in deconvolution. The last statement has both positive and negative implications. The method does provide control over which peaks are and are not used in the analysis; however, incorrect results could be obtained if a component were necessary, but not available.

Fortunately, most samples (even complex gamma-ray spectra of primary reactor coolant, mixtures of natural radionuclides and their decay series, and neutron activation analysis) contain nuclides that are known a priori. As a result, libraries can be constructed which include all radionuclides likely to be in n sample. Although the best accuracy obtained from library-directed methods occurs when the library exactly matches the peak energies present in the sample, it is possible to use other logical criteria to qualify nuclides and peaks used in the analysis, allowing larger libraries 10 be utilized.

The ability to control deconvolution by modifying the library and to find small non-Gaussian peaks

provides two key advantages over peak-search-directed methods for quantitative analysis.

313 Results Following the methods recommended in the. proposed ANSI N-42.14 standard,' a comparison of the two methods resulted in several sized psaks riding on a varying background to be found by the library-directed method bul missed by the peak search. Other tests from the standard were performed to measure the accuracy of doublet deconvulmion. Library-direcied methods resulted in better than 0.3% error for peaks separated by 2-FWHM and errors of less than 5% for peaks separated by 0.25-FWHM, a condition that exceeds the energy separation requirement for deconvolution by a factor of 8. Additional tests of both synthetic and natural spectra are presented, reporting the accuracy of the method as a function of peak energy separation and relative peak heights.

Both methods are tools that provide specific benefits for analysis. Neither is adequnte in itself; the peak search identifies any peaks that may be present but unanticipated. These peaks can then be added to a library to calculate a nuclide activity or to unfold a multiple!.3 After the peak search, a library-directed analysis performs the quantitative analysis. By combining the advantages of both methods, the spectroscopisi can use the tools appropriate for each job to obtain superlative results.

References 1. R. Gunnick & R. Niday, Computerized Quantitative Analysis by Gamma-Ray Spectroscopy, Description of the GAMANAL Program, Vol. 1, Lawrence Livermore Laboratory UCRL-51061, 1972.

2. M. Mariscotti, "A Method for Automatic Identification of Peaks in the Presence of Background and lis Application to Spectrum Analysis," Nuclear Instruments und Methods 50, pp. 309-320.

3. Calibration and Use of Germanium Detector for the Measurement of Gamma-Ray Emission Rates of Radionuclides, proposed 1990 standard, ANSI N-42.14, R, Gehrke, Chairman.

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