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Fission theory and actinide fission data

Abstract

The understanding of the fission process has made great progress recently, as a result of the calculation of fission barriers, using the Strutinsky prescription. Double-humped shapes were obtained for nuclei in the actinide region. Such shapes could explain, in a coherent manner, many different phenomena: fission isomers, structure in near-threshold fission cross sections, intermediate structure in subthreshold fission cross sections and anisotropy in the emission of the fission fragments. A brief review of fission barrier calculations and relevant experimental data is presented. Calculations of fission cross sections, using double-humped barrier shapes and fission channel properties, as obtained from the data discussed previously, are given for some U and Pu isotopes. The fission channel theory of A. Bohr has greatly influenced the study of low-energy fission. However, recent investigation of the yields of prompt neutrons and γ rays emitted in the resonances of {sup 235}U and {sup 239}Pu, together with the spin determination for many resonances of these two nuclei cannot be explained purely in terms of the Bohr theory. Variation in the prompt neutron and γ-ray yields from resonance to resonance does not seem to be due to such fission channels, as was thought previously, but to the effect of  More>>
Authors:
Publication Date:
Jun 01, 1975
Product Type:
Conference
Report Number:
CEA-CONF-3001
Resource Relation:
Conference: 4. Conference on nuclear cross sections and technology, Washington, DC, USA, 3-7 Mar 1975
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ACTINIDES; BOHR-WHEELER THEORY; FISSION; FISSION BARRIER; STRUTINSKY THEORY; DC - 34 - Physics-General
OSTI ID:
12525087
Research Organizations:
CEA Centre d' Etudes de Bruyeres-le-Chatel, 92 - Montrouge (France)
Country of Origin:
France
Language:
English
Submitting Site:
FRN
Size:
12 p.
Announcement Date:
Oct 04, 2013

Citation Formats

Michaudon, A. Fission theory and actinide fission data. France: N. p., 1975. Web.
Michaudon, A. Fission theory and actinide fission data. France.
Michaudon, A. 1975. "Fission theory and actinide fission data." France.
@misc{etde_12525087,
title = {Fission theory and actinide fission data}
author = {Michaudon, A.}
abstractNote = {The understanding of the fission process has made great progress recently, as a result of the calculation of fission barriers, using the Strutinsky prescription. Double-humped shapes were obtained for nuclei in the actinide region. Such shapes could explain, in a coherent manner, many different phenomena: fission isomers, structure in near-threshold fission cross sections, intermediate structure in subthreshold fission cross sections and anisotropy in the emission of the fission fragments. A brief review of fission barrier calculations and relevant experimental data is presented. Calculations of fission cross sections, using double-humped barrier shapes and fission channel properties, as obtained from the data discussed previously, are given for some U and Pu isotopes. The fission channel theory of A. Bohr has greatly influenced the study of low-energy fission. However, recent investigation of the yields of prompt neutrons and γ rays emitted in the resonances of {sup 235}U and {sup 239}Pu, together with the spin determination for many resonances of these two nuclei cannot be explained purely in terms of the Bohr theory. Variation in the prompt neutron and γ-ray yields from resonance to resonance does not seem to be due to such fission channels, as was thought previously, but to the effect of the (n,γf) reaction. The number of prompt fission neutrons and the kinetic energy of the fission fragments are affected by the energy balance and damping or viscosity effects in the last stage of the fission process, from saddle point to scission. These effects are discussed for some nuclei, especially for {sup 240}Pu.}
place = {France}
year = {1975}
month = {Jun}
}