摘要：

To understand the abundances of isotopes produced by the slow neutron capture process (s-process) in massive stars, we need improved knowledge of the neutron sources and poisons. Especially in stars with low metallicity, 16O is, due to its large abundance, a potential neutron poison, removing neutrons from the s-process in the 16O(n,γ) reaction. Some of the neutrons are, however, recycled by the 17O(α,n)20Ne reaction. The 17O(α,n)20Ne / 17O(α,γ)21Ne reaction rate ratio thus determines the poisonous effect of 16O and the s-process efficiency. This ratio is therefore crucial to providing reliable calculations for the s- process in low metallicity stars. There is currently little experimental data on the 17O(α,γ)21Ne reaction. Together with previously published values of the 17O(α,n)20Ne reaction, the 17O(α,γ)21Ne reaction data can be used to determine whether the ratio is closer to that predicted by Descouvemont [1] or that of Caughlan and Fowler [2]. We have measured the 17O(α,γ)21Ne reaction in inverse kinematics over the c.m. energy range 620-1600 keV at the DRAGON facility of TRIUMF.

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