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Title: Failure of the Woods-Saxon nuclear potential to simultaneously reproduce precise fusion and elastic scattering measurements

Abstract

A precise fusion excitation function has been measured for the {sup 12}C+{sup 208}Pb reaction at energies around the barrier, allowing the fusion barrier distribution to be extracted. The fusion cross sections at high energies differ significantly from existing fusion data. Coupled reaction channels calculations have been carried out with the code FRESCO. A bare potential previously claimed to uniquely describe a wide range of {sup 12}C+{sup 208}Pb near-barrier reaction channels failed to reproduce the new fusion data. The nuclear potential diffuseness of 0.95 fm which fits the fusion excitation function over a broad energy range fails to reproduce the elastic scattering. A diffuseness of 0.55 fm reproduces the fusion barrier distribution and elastic scattering data, but significantly overpredicts the fusion cross sections at high energies. This may be due to physical processes not included in the calculations. To constrain calculations, it is desirable to have precisely measured fusion cross sections, especially at energies around the barrier.

Authors:
; ; ; ;  [1];  [2]
  1. Department of Nuclear Physics, Research School of Physical Sciences and Engineering, Australian National University, Canberra, ACT 0200 (Australia)
  2. Department of Physics, Tohoku University, Sendai 980-8578 (Japan)
Publication Date:
OSTI Identifier:
20995217
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 75; Journal Issue: 4; Other Information: DOI: 10.1103/PhysRevC.75.044608; (c) 2007 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; CARBON 12; DISTRIBUTION; ELASTIC SCATTERING; ENERGY RANGE; EXCITATION FUNCTIONS; FAILURES; LEAD 208; WOODS-SAXON POTENTIAL

Citation Formats

Mukherjee, A., Hinde, D. J., Dasgupta, M., Newton, J. O., Butt, R. D., and Hagino, K.. Failure of the Woods-Saxon nuclear potential to simultaneously reproduce precise fusion and elastic scattering measurements. United States: N. p., 2007. Web. doi:10.1103/PHYSREVC.75.044608.
Mukherjee, A., Hinde, D. J., Dasgupta, M., Newton, J. O., Butt, R. D., & Hagino, K.. Failure of the Woods-Saxon nuclear potential to simultaneously reproduce precise fusion and elastic scattering measurements. United States. doi:10.1103/PHYSREVC.75.044608.
Mukherjee, A., Hinde, D. J., Dasgupta, M., Newton, J. O., Butt, R. D., and Hagino, K.. Sun . "Failure of the Woods-Saxon nuclear potential to simultaneously reproduce precise fusion and elastic scattering measurements". United States. doi:10.1103/PHYSREVC.75.044608.
@article{osti_20995217,
title = {Failure of the Woods-Saxon nuclear potential to simultaneously reproduce precise fusion and elastic scattering measurements},
author = {Mukherjee, A. and Hinde, D. J. and Dasgupta, M. and Newton, J. O. and Butt, R. D. and Hagino, K.},
abstractNote = {A precise fusion excitation function has been measured for the {sup 12}C+{sup 208}Pb reaction at energies around the barrier, allowing the fusion barrier distribution to be extracted. The fusion cross sections at high energies differ significantly from existing fusion data. Coupled reaction channels calculations have been carried out with the code FRESCO. A bare potential previously claimed to uniquely describe a wide range of {sup 12}C+{sup 208}Pb near-barrier reaction channels failed to reproduce the new fusion data. The nuclear potential diffuseness of 0.95 fm which fits the fusion excitation function over a broad energy range fails to reproduce the elastic scattering. A diffuseness of 0.55 fm reproduces the fusion barrier distribution and elastic scattering data, but significantly overpredicts the fusion cross sections at high energies. This may be due to physical processes not included in the calculations. To constrain calculations, it is desirable to have precisely measured fusion cross sections, especially at energies around the barrier.},
doi = {10.1103/PHYSREVC.75.044608},
journal = {Physical Review. C, Nuclear Physics},
number = 4,
volume = 75,
place = {United States},
year = {Sun Apr 15 00:00:00 EDT 2007},
month = {Sun Apr 15 00:00:00 EDT 2007}
}
  • The elastic and large-angle quasi-elastic scattering reactions were studied with the same nucleus-nucleus potential proposed for describing fusion reactions. The elastic scattering angle distributions of some reactions are reasonably well reproduced by the proposed Woods-Saxon potential with fixed parameters at energies much higher than the Coulomb barrier. With an empirical barrier distribution based on the modified Woods-Saxon potential and taking into account the influence of nucleon transfer, the calculated quasi-elastic scattering cross sections of a series of reactions are in good agreement with the experimental data.
  • New /sup 16/O + /sup 28/Si elastic scattering data have been obtained at 215.2 MeV laboratory bombarding energy which show no evidence of strong rainbow scattering effects. It is found that it is possible to simultaneously fit low and high energy data with the same energy-independent Woods-Saxon optical potential. It is found that the imaginary potential for such fits is greater than or equal to the real potential in the surface region and that a marked preference is found for a real well depth of about 10 MeV, as determined in the region of the nuclear surface. (AIP)
  • A modified Woods-Saxon potential model is proposed for a unified description of the entrance channel fusion barrier and the fission barrier of fusion-fission reactions based on the Skyrme energy-density functional approach. The fusion excitation functions of 120 reactions were systematically studied. The fusion (capture) cross sections are well described with the calculated potential and an empirical barrier distribution. Incorporating a statistical model (HIVAP code) for describing the decay of the compound nucleus, the evaporation residue (and fission) cross sections of 51 fusion-fission reactions have been systematically investigated. Optimal values of some key parameters of the HIVAP code are obtained basedmore » on the experimental data of these reactions. The experimental data are reasonably well reproduced by the calculated results. The upper and lower confidence limits of the systematic errors of the calculated results are given.« less