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标题：First measurements of the total and partial stellar neutron cross sections to the s-process branching-point 79Se
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作者：I. Dillmann, M.,Heil ; F. Käppeler ; T. Faestermann 等
期刊名称：PoS - Proceedings of Science
印刷版ISSN：1824-8039
出版年度：2006
出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：Although 79Se represents an important branching in the weak s process, the stellar neutron capture cross sections to this isotope have not yet been measured experimentally. In this case, experimental data is essential for evaluating the important branching in the s-process reaction path at 79Se. The total cross section of 78Se at a stellar energy of kT = 25 keV has been investigated with a combination of the activation technique and accelerator mass spectrometry (AMS), since offline decay counting is prohibitive due to the long terrestrial half life of 79Se (2.80±0.36 ×105 y [1]) as well as the absence of suitable g -ray transitions. The preliminary result for the total Maxwellian averaged cross section is < s >30 keV = 60.1±9.6 mbarn, significantly lower than the previous recommended value. In a second measurement, also the partial cross section to the 3.92 minisomer was determined via g -spectroscopy and yielded ~~30 keV (part.)= 42.0±2.0 mbarn.~~