Lanthanum: An s- and r-Process Indicator
Lanthanum: An s- and r-Process Indicator
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镧：s 和 r 过程指示器
DOI：
10.1086/505026
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
M. Pignatari
中科院分区：
文献类型：
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作者：
N. Winckler;S. Dababneh;M. Heil;F. Käppeler;R. Gallino;M. Pignatari
通过活化技术在 kT = 5 keV 的热能下测量了 139La 的中子俘获截面。在卡尔斯鲁厄 3.7 MV 脉冲范德格拉夫加速器的准恒星中子谱中进行了 3 次辐照，并通过 HPGe 三叶草探测器测量了诱导的活动。最终横截面为 113.7 ± 4.0 mbarn，比之前假设的高 10%。结合早期在 kT = 25 keV 处的测量，可以可靠地插值主要 s 过程组件相关热能处（即 kT = 8 和 23 keV 处）的麦克斯韦平均中子俘获截面。根据这些数据获得的 s 丰度表明，r 过程对太阳能镧的贡献 Nr = N☉ - Ns 为 30%。这与金属极其贫乏且 r 过程非常丰富的恒星的镧丰度非常吻合。
The neutron capture cross section of 139La has been measured at a thermal energy of kT = 5 keV by means of the activation technique. Three irradiations were performed in a quasi-stellar neutron spectrum at the Karlsruhe 3.7 MV pulsed Van de Graaff accelerator, and the induced activities were measured by means of HPGe clover detectors. The final cross section of 113.7 ± 4.0 mbarn was found to be 10% higher than that previously assumed. Together with an earlier measurement at kT = 25 keV, Maxwellian-averaged neutron capture cross sections at the relevant thermal energies of the main s-process component, i.e., at kT = 8 and 23 keV, could be reliably interpolated. The s-abundances obtained on the basis of these data showed that the r-process contribution to solar lanthanum, Nr = N☉ - Ns, is 30%. This is in good agreement with the lanthanum abundance of extremely metal-poor and very r-process-rich stars.
使用斯巴鲁高色散摄谱仪对极度贫金属恒星进行光谱研究。
DOI：
--
发表时间：
2004
期刊：
ApJ 607
影响因子：
--
作者：
I.Kanamori;N.Kawamoto;S.Honda
通讯作者：
S.Honda