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Title: Multifragmentation in intermediate energy 129Xe-induced heavy-ion reactions

Abstract

The 129Xe-induced reactions on natCu, 89Y, 165Ho, and 197Au at bombarding energies of E/A = 40 & 60 MeV have been studied theoretically and experimentally in order to establish the underlying mechanism of multifragmentation at intermediate energy heavy-Ion collisions. Nuclear disks formed in central heavy-ion collisions, as simulated by means of Boltzmann-like kinetic equations, break up into several fragments due to a new kind of Rayleigh-like surface instability. A sheet of liquid, stable in the limit of non-interacting surfaces, is shown to become unstable due to surface-surface interactions. The onset of this instability is determined analytically. A thin bubble behaves like a sheet and is susceptible to the surface instability through the crispation mode. The Coulomb effects associated with the depletion of charges in the central cavity of nuclear bubbles are investigated. The onset of Coulomb instability is demonstrated for perturbations of the radial mode. Experimental intermediate-mass-fragment multiplicity distributions for the 129Xe-induced reactions are shown to be binomial at each transverse energy. From these distributions, independent of the specific target, an elementary binary decay probability p can be extracted that has a thermal dependence. Thus it is inferred that multifragmentation is reducible to a combination of nearly independent emission processes.more » If sequential decay is assumed, the increase of p with transverse energy implies a contraction of the emission time scale. The sensitivity of p to the lower Z threshold in the definition of intermediate-mass-fragments points to a physical Poisson simulations of the particle multiplicities show that the weak auto-correlation between the fragment multiplicity and the transverse energy does not distort a Poisson distribution into a binomial distribution. The effect of device efficiency on the experimental results has also been studied.« less

Authors:
 [1]
  1. Univ. of California, Berkeley, CA (United States)
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
269000
Report Number(s):
LBNL-38884
ON: DE96013151; TRN: 96:017069
DOE Contract Number:  
AC03-76SF00098
Resource Type:
Thesis/Dissertation
Resource Relation:
Other Information: TH: Thesis (Ph.D.); PBD: May 1996
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; XENON 129 REACTIONS; NUCLEAR FRAGMENTATION; COPPER; YTTRIUM 89 TARGET; HOLMIUM 165 TARGET; GOLD 197 TARGET; CHARGE DISTRIBUTION

Citation Formats

Tso, Kin. Multifragmentation in intermediate energy 129Xe-induced heavy-ion reactions. United States: N. p., 1996. Web. doi:10.2172/269000.
Tso, Kin. Multifragmentation in intermediate energy 129Xe-induced heavy-ion reactions. United States. https://doi.org/10.2172/269000
Tso, Kin. 1996. "Multifragmentation in intermediate energy 129Xe-induced heavy-ion reactions". United States. https://doi.org/10.2172/269000. https://www.osti.gov/servlets/purl/269000.
@article{osti_269000,
title = {Multifragmentation in intermediate energy 129Xe-induced heavy-ion reactions},
author = {Tso, Kin},
abstractNote = {The 129Xe-induced reactions on natCu, 89Y, 165Ho, and 197Au at bombarding energies of E/A = 40 & 60 MeV have been studied theoretically and experimentally in order to establish the underlying mechanism of multifragmentation at intermediate energy heavy-Ion collisions. Nuclear disks formed in central heavy-ion collisions, as simulated by means of Boltzmann-like kinetic equations, break up into several fragments due to a new kind of Rayleigh-like surface instability. A sheet of liquid, stable in the limit of non-interacting surfaces, is shown to become unstable due to surface-surface interactions. The onset of this instability is determined analytically. A thin bubble behaves like a sheet and is susceptible to the surface instability through the crispation mode. The Coulomb effects associated with the depletion of charges in the central cavity of nuclear bubbles are investigated. The onset of Coulomb instability is demonstrated for perturbations of the radial mode. Experimental intermediate-mass-fragment multiplicity distributions for the 129Xe-induced reactions are shown to be binomial at each transverse energy. From these distributions, independent of the specific target, an elementary binary decay probability p can be extracted that has a thermal dependence. Thus it is inferred that multifragmentation is reducible to a combination of nearly independent emission processes. If sequential decay is assumed, the increase of p with transverse energy implies a contraction of the emission time scale. The sensitivity of p to the lower Z threshold in the definition of intermediate-mass-fragments points to a physical Poisson simulations of the particle multiplicities show that the weak auto-correlation between the fragment multiplicity and the transverse energy does not distort a Poisson distribution into a binomial distribution. The effect of device efficiency on the experimental results has also been studied.},
doi = {10.2172/269000},
url = {https://www.osti.gov/biblio/269000}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed May 01 00:00:00 EDT 1996},
month = {Wed May 01 00:00:00 EDT 1996}
}

Thesis/Dissertation:
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