Proton capture cross section of Sr isotopes and their importance for nucleosynthesis of proton-rich nuclides

Abstract

The $(p,\ensuremath{\gamma})$ cross sections of three stable Sr isotopes have been measured in the astrophysically relevant energy range. These reactions are important for the p process in stellar nucleosynthesis and, in addition, the reaction cross sections in the mass region up to 100 are also of importance concerning the $\mathrm{rp}$ process associated with explosive hydrogen and helium burning. It is speculated that this $\mathrm{rp}$ process could be responsible for a certain amount of p nuclei in this mass region. The $(p,\ensuremath{\gamma})$ cross sections of ${}^{84,86,87}\mathrm{Sr}$ isotopes were determined using an activation technique. The measurements were carried out at the 5 MV Van de Graaff accelerator of the ATOMKI, Debrecen. The resulting cross sections are compared with the predictions of statistical model calculations. The predictions are in good agreement with the experimental results for ${}^{84}\mathrm{Sr}(p,\ensuremath{\gamma}{)}^{85}\mathrm{Y}$ whereas the other two reactions exhibit differences that increase with mass number. The corresponding astrophysical reaction rates have also been computed.