Measurement of the Br(n,gamma) cross sections up to stellar s-process temperatures at the CSNS Back

分类： 物理学 >> 核物理学 分类： 物理学 >> 地球物理学、天文学和天体物理学 提交时间： 2023-09-12

Yang, Gaole An, Zhendong Jiang, Wei Li,Xiankai Qiu, Weiwei Liao, Zhengfa Zhuang, Ziyue Zhang, Xiaoping Chen,Shengli Xiao, Erxi Fang,Xiao Li,XinXiang Hu, Xinrong Jiang, Bing Wang, Jincheng Ren, Jie Luo, Wen Zhu, ZhiChao Lan, Haoyang Cao, Zongwei

摘要：The neutron capture cross sections (${n, upgamma}$) of Bromine was performed with the time-of-flight (TOF) technique at the Back-n facility of the China Spallation Neutron Source (CSNS). Prompt $ upgamma$-rays originating from neutron-induced capture events were detected by four C${}_6$D${}_6$ detectors. The pulse height weighting technique (PHWT) and the double-bunch unfolding method based on the Bayesian theory were used in the data analysis. To obtain reliable measurement results, background deductions, normalization, and corrections were carefully considered. The multilevel R-matrix Bayesian code SAMMY was used to extract the resonance parameters in the resolved resonance region (RRR). The average cross sections in unresolved resonance region the  was obtained from 10 to 400 keV. The experimental results were compared with the data of several evaluated libraries and previous experiments in the resolved and unresolved resonance region. The TALYS code was used to describe the average cross sections in the unresolved resonance region. Astrophysical Maxwell average cross sections (MACSs) of ${}^{79,81}$Br from $ kT $ = 5 to 100 keV was calculated over a sufficiently wide range of neutron energies. At a thermal energy of $kT=30$ keV, the MACS value for ${}^{79}$Br 638$ pm$64 mb is in good agreement with the KADoNiS recommended value. By contrast, the value of 293$ pm$29 mb for ${}^{81}$Br is substantially higher than those of the evaluated database and the KADoNiS recommended value.

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