s-process branchings at 151Sm, 154Eu, and 163Dy
s-process branchings at 151Sm, 154Eu, and 163Dy
复制标题
151Sm、154Eu 和 163Dy 处的 s 过程分支
DOI：
10.1103/physrevc.64.015801
复制
发表时间：
2001
影响因子：
3.1
通讯作者：
T. Rauscher
中科院分区：
文献类型：
--
作者：
Jason S. Best;H. Stoll;C. Arlandini;S. Jaag;F. Käppeler;K. Wisshak;A. Mengoni;G. Reffo;T. Rauscher
稳定铕同位素 Eu-151 和 Eu-153 的 (n, gamma) 截面是通过在准恒星中子谱中辐照氧化物样品来测量的。根据诱导活动，发现Eu-151和Eu-153在kT=30 keV热能下的恒星截面分别为σ/v(T)=3821+/-152 mb和2733+/-110 mb。这些结果使我们能够解决以前数据之间的严重差异。对 Sm-152、Sm-154 和 Er-164、Er-170 也进行了类似的活化测量。在这些结果中，仅 s 同位素 Er-164 [sigmav]/v(T)=1084+/-51 mb 在 kT=30 keV 时的恒星截面尤为重要。统计模型计算重点关注激发态以及不稳定同位素 Sm-151、Eu-152 和 Eu-154 的影响。组合的横截面集用于对 A=151、152、154 和 163 处的分支进行更新分析。讨论了通过经典方法得出的温度和密度估计，并与低质量恒星中氦壳燃烧的恒星模型进行了比较。
The (n, gamma) cross sections of the stable europium isotopes Eu-151 and Eu-153 have been measured by irradiating oxide samples in a quasistellar neutron spectrum. From the induced activities, the stellar cross sections of Eu-151 and Eu-153 at a thermal energy of kT=30 keV were found to be [sigmav]/v(T)=3821+/-152 mb and 2733 +/- 110 mb, respectively. These results allowed us to resolve severe discrepancies among previous data. Similar activation measurements were also performed on Sm-152,Sm-154 and Er-164,Er-170. Among these results, the stellar cross section of the s-only isotope Er-164 [sigmav]/v(T)=1084+/-51 mb at kT=30 keV is particularly important. Statistical model calculations were performed with emphasis on the effect of excited states as well as on the unstable isotopes Sm-151, Eu-152, and Eu-154. The combined set of cross sections was used for an updated analysis of the branchings at A=151, 152, 154, and 163. The temperature and density estimates derived via the classical approach are discussed and compared to stellar models for helium shell burning in low mass stars.