Neutron Capture Cross Sections for the Weak s Process
Neutron Capture Cross Sections for the Weak s Process
复制标题
弱过程的中子俘获截面
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
E. Uberseder
中科院分区：
文献类型：
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作者：
M. Heil;A. Juseviciute;F. Käppeler;R. Gallino;R. Gallino;M. Pignatari;M. Pignatari;E. Uberseder
摘要在过去的几十年里，人们对发生在热脉冲渐近巨星分支（AGB）恒星中的主要s过程的理解取得了很大的进展。在这个过程中，大约一半的重元素，主要是在90 ≤ A ≤ 209之间合成。改进了恒星模型以及测量相关的核数据，以便更好地描述主s过程。在大质量恒星（M ≥ 8 M <$）中，弱s过程有助于产生质量范围为56 ≤ A ≤ 90的较轻核，但人们对它的了解要少得多。更好地描述弱s分量将有助于理清这一区域元素生产的各种贡献。为此目的，在FZK的3.7 MV货车德格拉夫加速器上用活化法对中等质量核进行了一系列中子俘获截面的测量。此外，中子俘获大量A < 56的轻元素对s-过程核合成起着重要作用，因为它们充当中子毒物并影响恒星中子平衡。给出了41 K和45 Sc的（n，γ）截面的新结果，并根据改进的光谱信息对一些截面进行了修正。
Abstract In past decades a lot of progress has been made towards understanding the main s-process component that takes place in thermally pulsing Asymptotic Giant Branch (AGB) stars. During this process about half of the heavy elements, mainly between 90 ≤ A ≤ 209 are synthesized. Improvements were made in stellar modeling as well as in measuring relevant nuclear data for a better description of the main s process. The weak s process, which contributes to the production of lighter nuclei in the mass range 56 ≤ A ≤ 90 operates in massive stars (M ≥ 8 M⊙) and is much less understood. A better characterization of the weak s component would help disentangle the various contributions to element production in this region. For this purpose, a series of measurements of neutron-capture cross sections have been performed on medium-mass nuclei at the 3.7-MV Van de Graaff accelerator at FZK using the activation method. Also, neutron captures on abundant light elements with A < 56 play an important role for s-process nucleosynthesis, since they act as neutron poisons and affect the stellar neutron balance. New results are presented for the (n, γ) cross sections of 41K and 45Sc, and revisions are reported for a number of cross sections based on improved spectroscopic information.