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Title: Distribution of compound-nucleus shapes and its influence on evaporation

Abstract

The tail of the equilibrium distribution of compound-nucleus shapes is shown to extend out to very deformed shapes even for a moderate excitation energy of 100 MeV. The standard Hauser-Feshbach formalism is extended to predict the decay of a deformed compound nucleus as a function of spin, spin projection, and excitation energy. The inclusion of the equilibrium distributions of shapes is found to have little effect on the predicted neutron and proton kinetic energy spectra, but for {alpha} particles, the low-energy ''sub-barrier'' region of the spectrum is enhanced, in agreement with experimental data. Langevin simulations, using dissipation given by the wall formula, predict that compound nuclei start evaporating before the shape distribution equilibrates for excitation energies above {approx}100 MeV. (c) 2000 The American Physical Society.

Authors:
 [1]
  1. Department of Chemistry, Washington University, St. Louis, Missouri 63130 (United States)
Publication Date:
OSTI Identifier:
20216349
Resource Type:
Journal Article
Journal Name:
Physical Review. C, Nuclear Physics
Additional Journal Information:
Journal Volume: 61; Journal Issue: 5; Other Information: PBD: May 2000; Journal ID: ISSN 0556-2813
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; COMPOUND NUCLEI; NUCLEAR DEFORMATION; SPIN; HEAVY ION REACTIONS; PROTON SPECTRA; NEUTRON SPECTRA; THEORETICAL DATA

Citation Formats

Charity, R. J. Distribution of compound-nucleus shapes and its influence on evaporation. United States: N. p., 2000. Web. doi:10.1103/PhysRevC.61.054614.
Charity, R. J. Distribution of compound-nucleus shapes and its influence on evaporation. United States. doi:10.1103/PhysRevC.61.054614.
Charity, R. J. Mon . "Distribution of compound-nucleus shapes and its influence on evaporation". United States. doi:10.1103/PhysRevC.61.054614.
@article{osti_20216349,
title = {Distribution of compound-nucleus shapes and its influence on evaporation},
author = {Charity, R. J.},
abstractNote = {The tail of the equilibrium distribution of compound-nucleus shapes is shown to extend out to very deformed shapes even for a moderate excitation energy of 100 MeV. The standard Hauser-Feshbach formalism is extended to predict the decay of a deformed compound nucleus as a function of spin, spin projection, and excitation energy. The inclusion of the equilibrium distributions of shapes is found to have little effect on the predicted neutron and proton kinetic energy spectra, but for {alpha} particles, the low-energy ''sub-barrier'' region of the spectrum is enhanced, in agreement with experimental data. Langevin simulations, using dissipation given by the wall formula, predict that compound nuclei start evaporating before the shape distribution equilibrates for excitation energies above {approx}100 MeV. (c) 2000 The American Physical Society.},
doi = {10.1103/PhysRevC.61.054614},
journal = {Physical Review. C, Nuclear Physics},
issn = {0556-2813},
number = 5,
volume = 61,
place = {United States},
year = {2000},
month = {5}
}