Effects of uncertainties of the 22Ne(α, n)25Mg and 13C(α, n)16O reaction rates in the s-process yields

被引:4
作者
Pignatari, M
Gallino, R
Käppeler, F
Wiescher, M
机构
[1] Univ Turin, Dept Genie Phys, I-10125 Turin, Italy
[2] Forschungszentrum Karlsruhe, Inst Kernphys, D-76021 Karlsruhe, Germany
[3] Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA
关键词
D O I
10.1016/j.nuclphysa.2005.05.098
中图分类号
O57 [原子核物理学、高能物理学];
学科分类号
070202 ;
摘要
In the low mass star AGB phase the region between H shell and He shell (He-intershell) is affected by brief convective instabilities (Thermal Pulses), due to trigger of the He burning in the He shell. In this conditions the neutron source Ne-22(alpha, n) Mg-25 is marginally activated (releasing a short neuton burst with a peak neutron density n(n) < 10(10) n cm(-3)), and may change isotopic ratios near s-path branchings sensitive to the peak neutron density. For each element we analyse the isotopic ratios obtained in the AGB nucleosynthesis model using three different Ne-22(alpha, n) Mg-25 rates: first,with the "standard rate", evaluated in [I]; second, with the standard rate multiplied by a factor of two, and third, the standard rate divided by a factor of two. This factor is close to the present uncertainty factor of the Ne-22(alpha,n)Mg-25 rate. The same analysis is presented for C-13 (alpha, n) O-16 reaction rate, the primary neutron source in the He-intershell, which works in radiative conditions in a thin region in the top layers of the He-intershell (C-13-pocket) during interpulse periods. In this case the standard rate is evaluated in [2].
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页码:541C / 544C
页数:4
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