Astrophysical S(E) for the 9Be(p, d)8Be and 9Be(p, α)6Li Reactions by Direct Measurement

Abstract

Abstract The p–9Be reactions play a key role in accurate prediction of the primordial abundance of beryllium, and its abundance can be used to exquisitely probe the nucleosynthesis and mixing mechanism of stars. In the present work, astrophysical S(E) factors of the 9Be(p, d)8Be and 9Be(p, α)6Li reactions have been obtained from the thick-target yield Yield(E i) for proton energies from 18 to 100 keV. A full R-matrix analysis was performed to fit both the 9Be(p, α)6Li and 9Be(p, d)8Be reactions simultaneously. The resulting astrophysical S(E) factors agree well with direct measurements, leading to S(0) = 17.3 ± 2.1 and 13.9 ± 1.8 MeV·b for the 9Be(p, α)6Li and 9Be(p, d)8Be reactions, respectively. However, the obtained screening potential (U s = 512 ± 77 eV) is lower than results of previous work (900 ± 50 and 806 eV), and all of them are larger than the adiabatic limit of 264 eV. The reaction rates were also calculated in the temperature range (0.01–1) ⨯ 109 K, which improves on the precision of the standard database NACRE and NACRE II.