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Title: Extended optical model analyses of elastic scattering, direct reaction, and fusion cross sections for the {sup 9}Be+{sup 208}Pb system at near-Coulomb-barrier energies

Abstract

Based on the extended optical model approach in which the polarization potential is decomposed into direct reaction (DR) and fusion parts, simultaneous {chi}{sup 2} analyses are performed for elastic scattering, DR, and fusion cross section data for the {sup 9}Be+{sup 208}Pb system at near-Coulomb-barrier energies. Similar {chi}{sup 2} analyses are also performed by taking into account only the elastic scattering and fusion data as was previously done by the present authors, and the results are compared with those of the full analysis including the DR cross section data as well. We find that the analyses using only elastic scattering and fusion data can produce very consistent and reliable predictions of cross sections, particularly when the DR cross section data are incomplete. Discussions are also given on the results obtained from similar analyses made earlier for the {sup 9}Be+{sup 209}Bi system.

Authors:
; ; ;  [1];  [2];  [3]
  1. Laboratory of Cyclotron Application, Korea Institute of Radiological and Medical Sciences, Seoul 139-706 (Korea, Republic of)
  2. (Korea, Republic of)
  3. (United States)
Publication Date:
OSTI Identifier:
20771111
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 72; Journal Issue: 6; Other Information: DOI: 10.1103/PhysRevC.72.064602; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; BERYLLIUM 9; BERYLLIUM 9 REACTIONS; BISMUTH 209; BISMUTH 209 TARGET; COULOMB FIELD; CROSS SECTIONS; DIRECT REACTIONS; ELASTIC SCATTERING; LEAD 208; LEAD 208 TARGET; OPTICAL MODELS; POLARIZATION; POTENTIALS

Citation Formats

So, W.Y., Hong, S.W., Kim, B.T., Udagawa, T., Department of Physics and Institute of Basic Science, Sungkyunkwan University, Suwon 440-746, and Department of Physics, University of Texas, Austin, Texas 78712. Extended optical model analyses of elastic scattering, direct reaction, and fusion cross sections for the {sup 9}Be+{sup 208}Pb system at near-Coulomb-barrier energies. United States: N. p., 2005. Web. doi:10.1103/PhysRevC.72.064602.
So, W.Y., Hong, S.W., Kim, B.T., Udagawa, T., Department of Physics and Institute of Basic Science, Sungkyunkwan University, Suwon 440-746, & Department of Physics, University of Texas, Austin, Texas 78712. Extended optical model analyses of elastic scattering, direct reaction, and fusion cross sections for the {sup 9}Be+{sup 208}Pb system at near-Coulomb-barrier energies. United States. doi:10.1103/PhysRevC.72.064602.
So, W.Y., Hong, S.W., Kim, B.T., Udagawa, T., Department of Physics and Institute of Basic Science, Sungkyunkwan University, Suwon 440-746, and Department of Physics, University of Texas, Austin, Texas 78712. Thu . "Extended optical model analyses of elastic scattering, direct reaction, and fusion cross sections for the {sup 9}Be+{sup 208}Pb system at near-Coulomb-barrier energies". United States. doi:10.1103/PhysRevC.72.064602.
@article{osti_20771111,
title = {Extended optical model analyses of elastic scattering, direct reaction, and fusion cross sections for the {sup 9}Be+{sup 208}Pb system at near-Coulomb-barrier energies},
author = {So, W.Y. and Hong, S.W. and Kim, B.T. and Udagawa, T. and Department of Physics and Institute of Basic Science, Sungkyunkwan University, Suwon 440-746 and Department of Physics, University of Texas, Austin, Texas 78712},
abstractNote = {Based on the extended optical model approach in which the polarization potential is decomposed into direct reaction (DR) and fusion parts, simultaneous {chi}{sup 2} analyses are performed for elastic scattering, DR, and fusion cross section data for the {sup 9}Be+{sup 208}Pb system at near-Coulomb-barrier energies. Similar {chi}{sup 2} analyses are also performed by taking into account only the elastic scattering and fusion data as was previously done by the present authors, and the results are compared with those of the full analysis including the DR cross section data as well. We find that the analyses using only elastic scattering and fusion data can produce very consistent and reliable predictions of cross sections, particularly when the DR cross section data are incomplete. Discussions are also given on the results obtained from similar analyses made earlier for the {sup 9}Be+{sup 209}Bi system.},
doi = {10.1103/PhysRevC.72.064602},
journal = {Physical Review. C, Nuclear Physics},
number = 6,
volume = 72,
place = {United States},
year = {Thu Dec 15 00:00:00 EST 2005},
month = {Thu Dec 15 00:00:00 EST 2005}
}
  • Based on the extended optical model approach in which the polarization potential is decomposed into direct reaction (DR) and fusion parts, simultaneous {chi}{sup 2} analyses are performed for elastic scattering and fusion cross section data for the {sup 6}Li+{sup 208}Pb system at near-Coulomb-barrier energies. A folding potential is used as the bare potential. It is found that the real part of the resultant DR part of the polarization potential is repulsive, which is consistent with the results from the continuum discretized coupled channel (CDCC) calculations and the normalization factors needed for the folding potentials. Further, it is found that bothmore » DR and fusion parts of the polarization potential satisfy separately the dispersion relation.« less
  • Simultaneous {chi}{sup 2} analyses previously made for elastic scattering and fusion cross section data for the {sup 6}Li+{sup 208}Pb system are extended to the {sup 7}Li+{sup 208}Pb system at near-Coulomb-barrier energies based on the extended optical model approach, in which the polarization potential is decomposed into direct reaction (DR) and fusion parts. Use is made of the double folding potential as a bare potential. It is found that the experimental elastic scattering and fusion data are well reproduced without introducing any normalization factor for the double folding potential and that both the DR and fusion parts of the polarization potentialmore » determined from the {chi}{sup 2} analyses satisfy separately the dispersion relation. Further, we find that the real part of the fusion portion of the polarization potential is attractive while that of the DR part is repulsive except at energies far below the Coulomb barrier energy. A comparison is made of the present results with those obtained from the coupled discretized continuum channels calculations and a previous study based on the conventional optical model with a double folding potential. We also compare the present results for the {sup 7}Li+{sup 208}Pb system with the analysis previously made for the {sup 6}Li+{sup 208}Pb system.« less
  • Simultaneous {chi}{sup 2} analyses are performed for elastic scattering and fusion cross section data for the {sup 12}C+{sup 208}Pb system at near-Coulomb-barrier energies by using the extended optical model approach in which the polarization potential is decomposed into direct reaction (DR) and fusion parts. Use is made of the double folding potential as a bare potential. It is found that the experimental elastic scattering and fusion data are well reproduced without introducing any normalization factor for the double folding potential and also that both DR and fusion parts of the polarization potential determined from the {chi}{sup 2} analyses satisfy separatelymore » the dispersion relation. Furthermore, it is shown that the imaginary parts of both DR and fusion potentials at the strong absorption radius change very rapidly, which results in a typical threshold anomaly in the total imaginary potential as observed with tightly bound projectiles such as {alpha}-particle and {sup 16}O.« less
  • Based on the optical model, simultaneous chi/sup 2/ analyses are performed on elastic scattering and fusion cross sections measured for the /sup 32/S+/sup 58,64/Ni systems at several energies around the Coulomb barrier. We take the imaginary part of the optical potential used to consist of a surface-type direct and a volume-type fusion terms, W/sub D/ and W/sub F/, respectively, the latter of which accounts for fusion. It is shown that such analyses can determine W/sub F/ and W/sub D/ fairly unambiguously, and that the potentials thus determined explain all of the characteristic features observed in the elastic scattering, fusion, andmore » direct reaction cross sections. It is also shown that the potential satisfies the dispersion relation at the strong absorption radius.« less
  • An explanation is offered for the large fusion radii obtained in the optical model description of heavy-ion fusion given by Udagawa {ital et} {ital al}. An extension of the model is suggested, and possible effects on the spin distribution are discussed. It is contended that the large fusion radii {ital cannot} be deduced from the elastic scattering alone. The role of Coulomb excitation for these systems is also discussed.