The88Sr(p,γ)89Yreaction at astrophysically relevant energies

Abstract

The cross section of the ${}^{88}\mathrm{Sr}(p,\ensuremath{\gamma}{)}^{89}\mathrm{Y}$ reaction was determined by in-beam measurements at energies ${E}_{p}=1.4--5\mathrm{MeV}$ relevant to the nucleosynthetic p process. At ${E}_{p}>~3.5\mathrm{MeV},$ the \ensuremath{\gamma} angular distributions were obtained by using one HPGe detector of 80% relative efficiency, whereas at ${E}_{p}<~3.5\mathrm{MeV}$ they were measured by means of an array of four HPGe detectors all shielded with BGO crystals for Compton background supression. Three of them had a relative efficiency ${\ensuremath{\epsilon}}_{r}\ensuremath{\approx}100%,$ whereas the remaining one had ${\ensuremath{\epsilon}}_{r}\ensuremath{\approx}78%.$ From the resulting cross sections, that lie in the 0.5-\ensuremath{\mu}b--5-mb range, astrophysical S factors and reaction rates have been derived. Cross sections, S factors, and reaction rates have also been calculated by means of the statistical model code MOST. A very good agreement between the experimental data and the theoretical predictions has been found.