Cross sections of the(n,p)reaction on theSe78andSe80isotopes measured for 13.73 MeV to 14.77 MeV and estimated for 10 MeV to 20 MeV neutron energies

Abstract

The cross sections of $^{78}\mathrm{Se}(n,\phantom{\rule{0.16em}{0ex}}p)^{78}\mathrm{As}$ and $^{80}\mathrm{Se}(n,\phantom{\rule{0.16em}{0ex}}p)^{80}\mathrm{As}$ reactions were measured at five neutron energies over the range 13.73 MeV to 14.77 MeV using $^{56}\mathrm{Fe}$ and $^{19}\mathrm{F}$ as monitor elements, respectively. The cross sections were also theoretically estimated using EMPIRE-II and TALYS codes over 10 MeV to 20 MeV neutrons and matched with the experimental cross sections by making proper choice of the model parameters. The theoretical and experimental cross sections of $^{80}\mathrm{Se}(n,\phantom{\rule{0.16em}{0ex}}p)^{80}\mathrm{As}$ reaction are smaller as compared to the $^{78}\mathrm{Se}(n,\phantom{\rule{0.16em}{0ex}}p)^{78}\mathrm{As}$ reaction at each neutron energy. This difference is attributed to the competing $^{80}\mathrm{Se}\left(n,\phantom{\rule{0.16em}{0ex}}2n\right)^{79}\mathrm{Se}$ and $^{80}\mathrm{Se}(n,\phantom{\rule{0.16em}{0ex}}\ensuremath{\alpha})^{77}\mathrm{Ge}^{\mathrm{m}}$ reactions, which effectively decrease the cross sections of $^{80}\mathrm{Se}(n,\phantom{\rule{0.16em}{0ex}}p)^{80}\mathrm{As}$ reaction as compared to that of the $^{78}\mathrm{Se}(n,\phantom{\rule{0.16em}{0ex}}p)^{78}\mathrm{As}$ reaction over the neutron energy range used in the present work. The cross sections of $^{78}\mathrm{Se}(n,\phantom{\rule{0.16em}{0ex}}p)^{78}\mathrm{As}$ and $^{80}\mathrm{Se}(n,\phantom{\rule{0.16em}{0ex}}p)^{80}\mathrm{As}$ reactions estimated by the EMPIRE-II code initially increase but later on decrease with neutron energy, respectively, above 16 MeV and 19 MeV, whereas those estimated by the TALYS code continuously increase with neutron energy. The present results indicate that the trends in the variation of cross section with neutron energy depend on the model used in the calculations. The cross sections of the $^{80}\mathrm{Se}(n,\phantom{\rule{0.16em}{0ex}}p)^{80}\mathrm{As}$ reaction at different neutron energies reported in the present work can be added as a new data in the nuclear data library.