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Title: Light-charged-particle emission in the matched reactions 280 MeV {sup 40}Ar+{sup 27}Al and 670 MeV {sup 55}Mn+{sup 12}C: Coincidence results

Abstract

Exclusive measurements of light-charged-particle ({sup 1}H, {sup 2}H, and {sup 4}He) energy spectra, angular distributions, and emission multiplicities are reported for the two reactions {sup 40}Ar+{sup 27}Al and {sup 55}Mn+{sup 12}C at a matched excitation energy of 127 MeV. Comparisons are made with statistical model predictions for the evaporative processes in these reactions, which can be characterized as emissions from rotational-energy-dominated systems. The model simulations do well in reproducing a broad range of angular distribution data and the {sup 4}He/{sup 1}H cross-section ratio, using spin distributions derived from fusion cross-section systematics. The same model parameters, however, predict particle energy spectra and coincidence cross sections which are inconsistent with the measurements for both reactions. These results support previous conclusions from model comparisons with inclusive data, and suggest fundamental flaws in the statistical model as applied to light-mass, high-spin, nuclear systems. (c) 2000 The American Physical Society.

Authors:
 [1];  [1];  [1];  [1];  [2];  [1];  [2];  [2];  [1];  [3]
  1. Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States)
  2. Department of Physics, Hope College, Holland, Michigan 49423 (United States)
  3. Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
Publication Date:
OSTI Identifier:
20216348
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; HEAVY ION REACTIONS; ARGON 40; ALUMINIUM 27; MANGANESE 55; CARBON 12; PROTONS; DEUTERONS; ALPHA PARTICLES; ANGULAR DISTRIBUTION; ENERGY SPECTRA; CROSS SECTIONS; COINCIDENCE METHODS; EXPERIMENTAL DATA; THEORETICAL DATA

Citation Formats

Brown, Craig M., Milosevich, Zoran, Kaplan, Morton, Vardaci, Emanuele, DeYoung, Paul A., Whitfield, James P., Peterson, Donald, Dykstra, Christopher, Karol, Paul J., and McMahan, Margaret A. Light-charged-particle emission in the matched reactions 280 MeV {sup 40}Ar+{sup 27}Al and 670 MeV {sup 55}Mn+{sup 12}C: Coincidence results. United States: N. p., 2000. Web. doi:10.1103/PhysRevC.61.054611.
Brown, Craig M., Milosevich, Zoran, Kaplan, Morton, Vardaci, Emanuele, DeYoung, Paul A., Whitfield, James P., Peterson, Donald, Dykstra, Christopher, Karol, Paul J., & McMahan, Margaret A. Light-charged-particle emission in the matched reactions 280 MeV {sup 40}Ar+{sup 27}Al and 670 MeV {sup 55}Mn+{sup 12}C: Coincidence results. United States. doi:10.1103/PhysRevC.61.054611.
Brown, Craig M., Milosevich, Zoran, Kaplan, Morton, Vardaci, Emanuele, DeYoung, Paul A., Whitfield, James P., Peterson, Donald, Dykstra, Christopher, Karol, Paul J., and McMahan, Margaret A. Mon . "Light-charged-particle emission in the matched reactions 280 MeV {sup 40}Ar+{sup 27}Al and 670 MeV {sup 55}Mn+{sup 12}C: Coincidence results". United States. doi:10.1103/PhysRevC.61.054611.
@article{osti_20216348,
title = {Light-charged-particle emission in the matched reactions 280 MeV {sup 40}Ar+{sup 27}Al and 670 MeV {sup 55}Mn+{sup 12}C: Coincidence results},
author = {Brown, Craig M. and Milosevich, Zoran and Kaplan, Morton and Vardaci, Emanuele and DeYoung, Paul A. and Whitfield, James P. and Peterson, Donald and Dykstra, Christopher and Karol, Paul J. and McMahan, Margaret A.},
abstractNote = {Exclusive measurements of light-charged-particle ({sup 1}H, {sup 2}H, and {sup 4}He) energy spectra, angular distributions, and emission multiplicities are reported for the two reactions {sup 40}Ar+{sup 27}Al and {sup 55}Mn+{sup 12}C at a matched excitation energy of 127 MeV. Comparisons are made with statistical model predictions for the evaporative processes in these reactions, which can be characterized as emissions from rotational-energy-dominated systems. The model simulations do well in reproducing a broad range of angular distribution data and the {sup 4}He/{sup 1}H cross-section ratio, using spin distributions derived from fusion cross-section systematics. The same model parameters, however, predict particle energy spectra and coincidence cross sections which are inconsistent with the measurements for both reactions. These results support previous conclusions from model comparisons with inclusive data, and suggest fundamental flaws in the statistical model as applied to light-mass, high-spin, nuclear systems. (c) 2000 The American Physical Society.},
doi = {10.1103/PhysRevC.61.054611},
journal = {Physical Review. C, Nuclear Physics},
issn = {0556-2813},
number = 5,
volume = 61,
place = {United States},
year = {2000},
month = {5}
}