The181Ta(7Li,5n)183Osreaction: Measurement and analysis of the excitation function and isomeric cross-section ratios

Abstract

Excitation function and isomeric cross-section ratios for the production of ${}^{183}{\mathrm{Os}}^{m,g}$ by ${}^{7}\mathrm{Li}$-induced reactions on ${}^{181}\mathrm{Ta}$ are obtained from the measurements of the residual activities by the conventional stacked-foils technique from threshold to 50 MeV. The excitation function and isomeric cross-section ratios for nuclear reaction ${}^{181}\mathrm{Ta}{(}^{7}\mathrm{Li}{,5n)}^{183}{\mathrm{Os}}^{m,g}$ are compared with the theoretical statistical model calculation by using the ALICE/91, STAPRE, and CASCADE codes. In the energy range of the present measurement the excitation functions are fitted fairly well by both the geometry dependent hybrid (GDH) model and the hybrid model of Blann with initial exciton number ${n}_{0}=7$ (${n}_{n}=4,$ ${n}_{p}=3,$ ${n}_{h}=0$) using the ALICE/91 code. The experimental isomeric cross-section ratios are also reproduced fairly well by the calculation using the STAPRE code. However, the CASCADE code calculations slightly underpredict the cross section but reproduce the shape. In general, the statistical model under a suitable set of global assumptions, can reproduce the excitation function as well as isomeric cross-section ratios.