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Fission of heavy nuclei: microscopic study of fission barriers and fragments angular momentum; Fission des noyaux lourds: etude microscopique des barrieres de fission et du moment angulaire des fragments

Abstract

A lot of experimental data on nuclear fission has been being collected for the last 65 years, allowing theoreticians to confront their models with reality. The first part of this work is dedicated to the computation of fission barriers. We have extended the HF + BCS (Hartree Fock + Bandeen-Cooper-Schrieffer) method in order to include a new set of polynomials on which wave functions can be broken to, more accurately than on Hermite's polynomials in the 2 fragment configuration. The fission barriers of 26 heavy nuclei from Thorium-230 to Nobelium-256 have been assessed and compared to experimental data, it appears that differences are no greater than 1 MeV. We have discovered a neat correlation between the variation of the experimental fission lifetimes of even Fermium isotopes and the computed heights of second barriers. Moreover our model reproduces the hyper-deformed well of Thorium-230 with a good agreement on the well depth. The second part deals with the scission region. We have performed Hartree-Fock calculations in order to explore different ways of fragmentation. We have shown that the harmonic oscillator gives a valid description of such ways. In order to compute the mean value of J{sup 2} in the fragments we have  More>>
Authors:
Publication Date:
Nov 01, 2003
Product Type:
Thesis/Dissertation
Report Number:
FRNC-TH-6194
Resource Relation:
Other Information: TH: These physique; 139 refs
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; CALIFORNIUM ISOTOPES; FERMIUM ISOTOPES; FISSION; FISSION BARRIER; FISSION FRAGMENTS; HARTREE-FOCK METHOD; NOBELIUM 252; NOBELIUM 256; NUCLEAR MODELS; PLUTONIUM 240; SCISSION-POINT MODEL; SPIN; THORIUM 230; THORIUM 232; URANIUM 234; URANIUM 236
OSTI ID:
20706628
Research Organizations:
Bordeaux-1 Univ. Sciences et Technologies, 33 (France)
Country of Origin:
France
Language:
French
Other Identifying Numbers:
TRN: FR0504099021833
Availability:
Available from INIS in electronic form
Submitting Site:
FRN
Size:
181 pages
Announcement Date:
Apr 27, 2006

Citation Formats

Bonneau, L. Fission of heavy nuclei: microscopic study of fission barriers and fragments angular momentum; Fission des noyaux lourds: etude microscopique des barrieres de fission et du moment angulaire des fragments. France: N. p., 2003. Web.
Bonneau, L. Fission of heavy nuclei: microscopic study of fission barriers and fragments angular momentum; Fission des noyaux lourds: etude microscopique des barrieres de fission et du moment angulaire des fragments. France.
Bonneau, L. 2003. "Fission of heavy nuclei: microscopic study of fission barriers and fragments angular momentum; Fission des noyaux lourds: etude microscopique des barrieres de fission et du moment angulaire des fragments." France.
@misc{etde_20706628,
title = {Fission of heavy nuclei: microscopic study of fission barriers and fragments angular momentum; Fission des noyaux lourds: etude microscopique des barrieres de fission et du moment angulaire des fragments}
author = {Bonneau, L}
abstractNote = {A lot of experimental data on nuclear fission has been being collected for the last 65 years, allowing theoreticians to confront their models with reality. The first part of this work is dedicated to the computation of fission barriers. We have extended the HF + BCS (Hartree Fock + Bandeen-Cooper-Schrieffer) method in order to include a new set of polynomials on which wave functions can be broken to, more accurately than on Hermite's polynomials in the 2 fragment configuration. The fission barriers of 26 heavy nuclei from Thorium-230 to Nobelium-256 have been assessed and compared to experimental data, it appears that differences are no greater than 1 MeV. We have discovered a neat correlation between the variation of the experimental fission lifetimes of even Fermium isotopes and the computed heights of second barriers. Moreover our model reproduces the hyper-deformed well of Thorium-230 with a good agreement on the well depth. The second part deals with the scission region. We have performed Hartree-Fock calculations in order to explore different ways of fragmentation. We have shown that the harmonic oscillator gives a valid description of such ways. In order to compute the mean value of J{sup 2} in the fragments we have been driven to propose an adequate definition of that quantity consistent with the non-locality property of the J{sup 2} operator. (A.C.)}
place = {France}
year = {2003}
month = {Nov}
}