Radiative neutron capture: Hauser Feshbach vs. statistical resonances

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• 作者：D. Rochman^a ; ^{dimitri-alexandre.rochman@psi.ch} ; S. Goriely^b ; A.J. Koning^c ; ^d ; H. Ferroukhi^a
• 关键词：Statistical Hauser&ndash ; Feshbach model ; Radiative neutron captures ; Nuclear astrophysics
• 刊名：Physics Letters B
• 出版年：2017
• 出版时间：10 January 2017
• 年：2017
• 卷：764
• 期：Complete
• 页码：109-113
• 全文大小：548 K
• 卷排序：764

文摘

The radiative neutron capture rates for isotopes of astrophysical interest are commonly calculated on the basis of the statistical Hauser Feshbach (HF) reaction model, leading to smooth and monotonically varying temperature-dependent Maxwellian-averaged cross sections (MACS). The HF approximation is known to be valid if the number of resonances in the compound system is relatively high. However, such a condition is hardly fulfilled for keV neutrons captured on light or exotic neutron-rich nuclei. For this reason, a different procedure is proposed here, based on the generation of statistical resonances. This novel technique, called the “High Fidelity Resonance” (HFR) method is shown to provide similar results as the HF approach for nuclei with a high level density but to deviate and be more realistic than HF predictions for light and neutron-rich nuclei or at relatively low sub-keV energies. The MACS derived with the HFR method are systematically compared with the traditional HF calculations for some 3300 neutron-rich nuclei and shown to give rise to significantly larger predictions with respect to the HF approach at energies of astrophysical relevance. For this reason, the HF approach should not be applied to light or neutron-rich nuclei. The Doppler broadening of the generated resonances is also studied and found to have a negligible impact on the calculated MACS.