Cross section measurements of proton capture reactions on Se isotopes relevant to the astrophysical p process

Abstract

Cross sections of proton capture reactions on $^{74}\mathrm{Se}$, $^{78}\mathrm{Se}$, and $^{80}\mathrm{Se}$ have been measured at incident beam energies from 2 to 6 MeV, 1.7 to 3 MeV, and 1.5 to 3.5 MeV, respectively. In the case of $^{78,80}\mathrm{Se}$, cross sections were obtained from in-beam $\ensuremath{\gamma}$-angular distribution measurements, whereas for the $^{74}\mathrm{Se}$ isotope they were derived from off-beam activity measurements. The measured cross sections were compared with calculations performed with the nuclear reaction code talys (version 1.6). A good agreement between theory and experiment was found. Astrophysical $S$ factors and reaction rates deduced from the experimental and calculated cross sections were also compared and the impact of different nuclear ingredients in the calculations on the reaction rates was investigated. It was found that, for certain combinations of nuclear input models, the reaction rates obtained at temperatures relevant to $p$-process nucleosynthesis differ by a factor 2 at the most, differences that are well within the acceptable deviations of calculated $p$-nuclei abundances and observations.