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Study of fast neutron scattering. The displacement cross-section (1962); Etude de la diffusion des neutrons rapides. Section efficace de deplacement (1962)

Abstract

We propose a method for calculating the biological efficiency of fast neutrons emitted by in-pile fission sources. This method justifies the empirical theory of Albert and Welton. In making simple assumptions concerning the cross-sections, we have supposed that the propagation can ben reduced to a mono-kinetic problem. A system of orthonormal functions is then set up making it possible to calculate the flux leaving a planar source. This method generalises the results obtained by Platzek to the case where the elastic cross-sections are not isotropic, and make it possible in particular to define a displacement cross-section: extension of the diffusion coefficient. This method can be generalised to the case of neutron diffraction as a function of time, and to the study of slowing-down. Numerical results are given in an appendix for the following: H{sub 2}O, D{sub 2}O, Fe, Be, Pb, CH, CH{sub 2}. These cross-sections have been verified experimentally in water and in graphite for neutrons of 2.5 and 14 MeV using a SAMES accelerator and a 2 MeV Van De Graaff. (author) [French] Nous proposons une methode permettant de calculer l'efficacite biologique des neutrons rapides issus des sources de fission dans la protection d'une pile. Cette methode justifie la  More>>
Authors:
Millot, J P [1] 
  1. Commissariat a l'Energie Atomique, Fontenay-aux-Roses (France). Centre d'Etudes Nucleaires
Publication Date:
Jul 01, 1962
Product Type:
Thesis/Dissertation
Report Number:
CEA-R-2142
Resource Relation:
Other Information: TH: These ES-sciences physiques; 15 refs
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ANISOTROPY; DIFFERENTIAL CROSS SECTIONS; FAST NEUTRONS; GEOMETRY; INELASTIC SCATTERING; KINETICS; LEGENDRE POLYNOMIALS; NEUTRON FLUX; PLACZEC FUNCTION; SLOWING-DOWN; TOTAL CROSS SECTIONS; VAN DE GRAAFF ACCELERATORS
OSTI ID:
20754707
Research Organizations:
CEA Fontenay-aux-Roses, 92 (France); Faculte des Sciences de l'Universite de Paris, 75 (France)
Country of Origin:
France
Language:
French
Other Identifying Numbers:
TRN: FR06R2142062502
Availability:
Available from INIS in electronic form
Submitting Site:
FRN
Size:
103 pages
Announcement Date:
Aug 11, 2006

Citation Formats

Millot, J P. Study of fast neutron scattering. The displacement cross-section (1962); Etude de la diffusion des neutrons rapides. Section efficace de deplacement (1962). France: N. p., 1962. Web.
Millot, J P. Study of fast neutron scattering. The displacement cross-section (1962); Etude de la diffusion des neutrons rapides. Section efficace de deplacement (1962). France.
Millot, J P. 1962. "Study of fast neutron scattering. The displacement cross-section (1962); Etude de la diffusion des neutrons rapides. Section efficace de deplacement (1962)." France.
@misc{etde_20754707,
title = {Study of fast neutron scattering. The displacement cross-section (1962); Etude de la diffusion des neutrons rapides. Section efficace de deplacement (1962)}
author = {Millot, J P}
abstractNote = {We propose a method for calculating the biological efficiency of fast neutrons emitted by in-pile fission sources. This method justifies the empirical theory of Albert and Welton. In making simple assumptions concerning the cross-sections, we have supposed that the propagation can ben reduced to a mono-kinetic problem. A system of orthonormal functions is then set up making it possible to calculate the flux leaving a planar source. This method generalises the results obtained by Platzek to the case where the elastic cross-sections are not isotropic, and make it possible in particular to define a displacement cross-section: extension of the diffusion coefficient. This method can be generalised to the case of neutron diffraction as a function of time, and to the study of slowing-down. Numerical results are given in an appendix for the following: H{sub 2}O, D{sub 2}O, Fe, Be, Pb, CH, CH{sub 2}. These cross-sections have been verified experimentally in water and in graphite for neutrons of 2.5 and 14 MeV using a SAMES accelerator and a 2 MeV Van De Graaff. (author) [French] Nous proposons une methode permettant de calculer l'efficacite biologique des neutrons rapides issus des sources de fission dans la protection d'une pile. Cette methode justifie la theorie empirique d'Albert et Welton. En faisant des hypotheses simples sur les sections efficaces, nous avons suppose que la propagation pouvait etre ramenee a un probleme monocinetique. Nous construisons alors un systeme de fonctions orthonormales qui permet de calculer le flux issu d'une source plane. Cette methode generalise les resultats obtenus par Platzek au cas ou les sections efficaces elastiques ne sont pas isotropes et en particulier permet de definir une section efficace de deplacement: extension du coefficient de diffusion. Cette methode peut etre generalisee a la diffusion des neutrons en fonction du temps et a l'etude du ralentissement. Les resultats numeriques sont donnes en annexe pour les corps. H{sub 2}O, D{sub 2}O, Fe, Be, Pb, CH, CH{sub 2}. Des verifications experimentales de ces sections efficaces ont ete effectuees a l'aide d'un accelerateur SAMES et d'un VAN DE GRAAFF de 2 MeV, dans l'eau et le graphite pour des neutrons d'energie de 2,5 et 14 MeV. (auteur)}
place = {France}
year = {1962}
month = {Jul}
}