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Zeitschrift für Physik A Atoms and Nuclei

, Volume 297, Issue 2, pp 161–183 | Cite as

Comparison of the fusion reactions12C+20Ne and16O+16O near the Coulomb barrier

  • G. Hulke
  • C. Rolfs
  • H. P. Trautvetter
Nuclei

Abstract

The partial cross sections of heavy residual nuclei produced in the heavy ion fusion of12C+20Ne have been measured atEc.m.=6–15 MeV viaγ-ray spectroscopy with a Ge(Li) detector. Windowless and recirculating gas target systems have been used. The dominant residual nuclei are24Mg,27Al,28Si,30Si,30P and31P, which arise from two- and three-body breakups in the exit channels. The observed excitation functions are smooth in their energy dependence and give no indications for the existence of pronounced resonance structures, in contrast to theoretical predictions. The Coulomb excitation of20Ne served as an intrinsic calibration standard in the determination of absolute partial and total fusion cross sections. The same experimental set-up was also used in the reaction studies of16O+16O atEc.m.=7–14 MeV, going through the same compound nucleus32S at similar excitation energies. The observed energy dependence in the excitation functions is in good agreement with previous work. The total fusion cross section agrees fairly well with two sets of values reported previously, but deviates significantly from other reported absolute cross section values. The relative evaporation distributions of the residual nuclei are similar for both heavy ion reactions. However, the ratio of their total fusion cross sections deviates from model predictions and suggests that compound nucleus formation does depend on the microscopic structure of the colliding nuclei in the entrance channel. From the observed energy dependence of the above ratio, particularly at subcoulomb energies, geometrical effects in the entrance channel (due to deformed and spherical nuclei) appear to be weak. The astrophysical aspects of the data in the context of late stellar nucleosynthesis are discussed.

Keywords

Excitation Function Compound Nucleus Entrance Channel Residual Nucleus Partial Cross Section 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag 1980

Authors and Affiliations

  • G. Hulke
    • 1
  • C. Rolfs
    • 1
  • H. P. Trautvetter
    • 1
  1. 1.Institut für Kernphysik der UniversitätMünsterGermany

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