De Bievre, P.

Debus, G.

Spaepen, J.

Archive of European Integration

jts¡9jjjjJH¡ œ P P ! « ^ Wsmw mm m iiwliiiliipi Ì l ; -iÉl^^^^ii^ » >fi r Λ B Ë H V â ) R 4 5 4 . REPRINT l i sir »frø»; EUROPEAN ATOMIC ENERGY COMMUNITY ­ EURATOM nm HtøiiW« Li»»"*6 SM f i«* mmÊHÊ ;■..-,. i . « Central Bureau for Nuclear Measurements Geel Establishment (Belgium) Reprinted from Reactor Science and Technology (Journal of Nuclear Energy Parts A/B) Vol. 17 ­ 1963 &£ΰ . . . . . . . T i T - , . ï fííftW &* LEGAL NOTICE > -ιι'ΑψΗφί* Vf m\ wm m This document was prepared under the sponsorship of the Commission of the European Atomic Energy Community (EURATOM). Neither the EURATOM Commission, its contractors nor any person acting on their behalf ■ , Mk . ifall ­ Make any warranty or representation, express or implied, with respect to the accuracy, completeness, or usefulness of the information contained in this document, or that the use of any information, apparatus, method, or process disclosed in this document may not infringe privately owned rights; or 1° — Assume any liability with respect to the use of, or for damages resulting from the use of any information, apparatus, method or process disclosed in this docnmpnt u e . The authors' names are listed in alphabetical order. ■jmsKñ «Sr mmwim >rint is intended for restricted distribution only. It U H - ¡/Willi *Mt£. 1wiliHlB3«iik*!i This repr. only. It reproduces, 1 - " * ! ! · " ]ieser Sonderdruck ist für eine beschränkte Verteilung bestimmt. Die Wiedergabe des vorliegenden in „REACTOR SCIENCE AND TECHNOLOGY" (Journal of Nuclear Energy Parts A/B), Vol. 17­1963, 349 erschienenen Aufsatzes erfolgt mit freundlicher Geneh­migung des Herausgebers. Bestellungen weiterer Exemplare sind an Pergamon Press — 4, Fitzroy Square, London, W.l. (England) Ce tiré­à­part est exclusivement destiné à une diffusion restreinte. Il reprend, avec l'aimable autorisation de l'éditeur, un article publié dans le «REACTOR SCIENCE AND TECHNOLOGY» (Journal of Nuclear Energy Parts AjBJ, Vol. 17 ­ 1963, 349. Tout autre exemplaire de cet article doit être demandé à Pergamon Press — 4, Fitzroy Square, London, W.l. (England). Questo estratto è destinato esclusivamente ad una diffusione limitata. Esso è stato riprodotto, per gentile concessione dell'Editore, da «RE­ACTOR SCIENCE AND TECHNOLOGY» (Journal of Nuclear Energy Parts A\B), Voi. 17­1963, 349. Ulteriori copie dell'articolo debbono essere richieste a Pergamon Press — 4, Fitzroy Square, London, W.l. (England). Deze overdruk is slechts voor beperkte verspreiding bestemd. Het artikel is met welwillende toestemming van de uitgever overgenomen uit „RE­ACTOR SCIENCE AND TECHNOLOGY" (Journal of Nuclear Energy Parts AJB), Vol. 17­1963, 349. Meer exemplaren kunnen besteld worden bij Pergamon Press — 4, Fitzroy Square, London, W.l. (England). 'ÜHaK »jPMSwiwseøji* W. E U R 4 5 4 . e REPRINT THERMAL NEUTRON ABSORPTION CROSS SECTION OF BORON by P. DE BIEVRE, G.H. DEBUS and J. SPAEPEN. European Atomic Energy Community - EURATOM. Central Bureau for Nuclear Measurements. Geel Establishment (Belgium). Reprinted from „Reactor Science and Technology,,. (Journal of Nuclear Energy Parts A/B) - Vol. 17, 1963 - page 349. Summary not available. E U R 4 5 4 . e REPRINT THERMAL NEUTRON ABSORPTION CROSS SECTION OF BORON by P. DE BIEVRE, G.H. DEBUS and J. SPAEPEN. European Atomic Energy Community - EURATOM. Central Bureau for Nuclear Measurements. Geel Establishment (Belgium). Reprinted from „Reactor Science and Technology,,. (Journal of Nuclear Energy Parts A/B) - Vol. 17, 1963 - page 349. Summary not available. E U R 4 5 4 . e REPRINT THERMAL NEUTRON ABSORPTION CROSS SECTION OF BORON by P. DE BIEVRE, G.H. DEBUS and J. SPAEPEN. European Atomic Energy Community - EURATOM. Central Bureau for Nuclear Measurements. Geel Establishment (Belgium). Reprinted from „Reactor Science and Technology,,. (Journal of Nuclear Energy Parts A/B) - Vol. 17, 1963 - page 349. Summary not available. Reprinted from REACTOR SCIENCE AND TECHNOLOGY Journal of Nuclear Energy Parts A & Β P E R G A M O N P R E S S OXFORD . LONDON . NEW YORK . PARIS Reactor Science and Technology (Journal of Nuclear Energy Paris A/B) 1963, Vol. 17. p. 349. Pergamon Press Lid. Primed in Northern Ireland. Thermal neutron absorption cross section of boron (Received 19 March 1963) T H E thermal neutron absorption cross section of boron has been measured in several laboratories and the discrepancies were not explained on a basis of statistical error calculation ( G R E E N et al., 1954; DERUYTTER et al., 1962). T H O D E et al. proved the variation of the isotopie concen­tration of boron with different geological origin and the dis­agreements in the cross­section values of natural boron have been partly ascribed to the boron samples used by the experi­mentalists of the different laboratories. During a recent intercomparison of samples taken from stocks of boron used as a standard in nuclear institutes, we obtained, by means of mass spectrometry, a series of results which agree with previous direct intercomparisons of the same stocks by oscillation techniques (GREEN et al.) Our results arc given in Table 1, which indicates the ratio of the atomic boron­10 content in the sample to the atomic boron­10 content in the Harwell boric acid standard. TABLE 1 A r g o n n c I Argonne 11 C . B . N . M . II Chalk River A .E .G. I­ontenay Cold F o m c n a y (new slock) s tock) Mass spec t rometer I 0­985 ­­­ 0­002 0­986 ± 0­002 0­986 ­J­ 0­003 0­9S6 t 0­003 0­984 ­i­ 0 0 0 2 0­9995 ± 0­002 0­997 ± 0­002 Mass spec t rometer II 0­983 ± 0­002 0­985 ­■■ 0­002 0­9S5 ± 0­003 0­9SS ­Í­ 0 0 0 2 0­9S6 ± 0­002 0­986 ­·­ 0­003 0­9995 ± 0­002 0­99S Í­ 0 0 0 2 Average 0­984 0­9S5. 0­9S5 0­9S7 0­9S6 0­985 0­9995 0­997r The Argonne I sample is boric acid, obtained from Wexler and Ringo, A.N.L., and was taken from the original stock used by GREEN et al. for cross­section measurements. This stock is now almost exhausted. The Argonne Π sample is a probe from 7001b boric acid mixed by Merck U.S. for A.N.L. The C.B.N.M. I sample is B a 0 3 from Merck, Germany and was used by DERUYTTER et al. for measurements of the thermal neutron absorption cross section of boron. The C.B.N.M. II sample is part of 200 kg boric acid prepared by Merck, Germany and mixed by the C.B.N.M. This stock of natural boron is to be distributed by C.B.N.M. in the countries of the European Community . The Chalk River sample is boric acid and originates from a boron standard at Chalk River, Canada. The A.E.G. sample is a probe from a large lot of boric acid prepared by Merck, Germany. The Fontenay 'old stock' and Fontenay 'new stock' samples are boric acid and originate probably from Turkey. The old stock has been used as a standard at Fontenay­aux­Roses, France. The Harwell sample was boric acid. From the present investigation, it seems worthwhile to mention the following observations: (1) The values obtained for the atomic boron­10 content of the two Argonnc samples, the two C.B.N.M. samples, the Canadian sample (Chalk River) and the A.E.G. sample' (Germany) are identical within the statistical fluctuations. The quoted errors are such that the measured value has a 99 per cent probability not to exceed the indicated limits. (2) The British (Harwell) and the two French (Fontenay Old ' and 'new') samples are significantly different in atomic boron­10 content from the others but are themselves also identical within the limits of statistical fluctuations. This result is in agreement with the value of the ratio in­dicated by G R E E N et al. of the thermal boron absorption cross section of the Argonne­Brookhaven standards to the thermal boron absorption cross section of the Harwell one, obtained by oscillation in GLEEP. Central Bureau for Nuclear Measurements TJ'TVU U r . D E BIEVRE J. SPAEPEN _ Euratom, Geel, Beteiu R E F E R E N C E S DERUYTTER Α., DEBUS G., LAUER Κ., M O R E T Η. and PROSDOC­IMI A. (1962) Measurements of the Thermal Neutron Absorp­tion Cross Section of Boron bv Means of a Time­of­FIi"ht Technique. Report E U R 12.e. G R E E N Α., LITTLER D . J., LOCKETT E. E.. SMALL V. G.. S P U R ­WAYA. H . and BOWEL E. (1954) J. Nucl. Energy 1, 144. T H O D E H. G., MACNAMARA J., LOSSING F. P. and COLLINS C Β (1948) J. Amer. ehem. Soc. 70, 3005. ΠΒ«ηρηυ<·ι·*2£Μ ι'''Μίΰ',ίΑίΚΪ.! w'^mÊi lp ¿ηpst* -Γ.;;'»'-iin-'i-Hr-fiΦίβΒκίκ;»·"»^,·'^^'^yiafiaSBf ' II . . , i , r f fr · I ί,Γ,ίίΙί. if 'w ' ' ' . i i ; , . ι ". I 111 ' ■«Ά· ! Warn slïiï lîfiî' f «' - ι,.·>ί<ί..*Ρ·*[: l i . ι . , & Ι Φ ί ΙΙΙΙΙΒΙΙ i fL Aliali Fit I-M '4Îlftï trofei; CDNA00454ENC ÉKiÉISiíiiÉgiilAíel! 

THERMAL NEUTRON ABSORPTION CROSS SECTION OF BORON. EUR 454.e

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