Coupled-Channel Models of Direct-Semidirect Capture via Giant-Dipole Resonances

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• 作者：I.J. Thompson^a ; ^{I-Thompson@llnl.gov" class="auth_mail} ; J.E. Escher^a ; G. Arbanas^b
• 刊名：Nuclear Data Sheets
• 出版年：April 2014
• 年：2014
• 卷：118
• 期：Complete
• 页码：292-294
• 全文大小：287 K

文摘

Semidirect capture, a two-step process that excites a giant-dipole resonance followed by its radiative de-excitation, is a dominant process near giant-dipole resonances, that is, for incoming neutron energies within 5–20 MeV. At lower energies such processes may affect neutron capture rates that are relevant to astrophysical nucleosynthesis models. We implement a semidirect capture model in the coupled-channel reaction code Fresco and validate it by comparing the cross section for direct-semidirect capture ²⁰⁸Pb(n,纬)²⁰⁹Pb to experimental data. We also investigate the effect of low-energy electric dipole strength in the pygmy resonance. We use a conventional single-particle direct-semidirect capture code Cupido for comparison. Furthermore, we present and discuss our results for direct-semidirect capture reaction ¹³⁰Sn(n,纬)¹³¹Sn, the cross section of which is known to have a significant effect on nucleosynthesis models.