Excitation Functions for Inelastic Scattering Reactions of Cadmium-111 and Indium-115

Abstract

Excitation functions have been measured for the formation of ${\mathrm{Cd}}^{111m}$ and ${\mathrm{In}}^{115m}$ in the bombardment of ${\mathrm{Cd}}^{111}$ and ${\mathrm{In}}^{115}$, respectively, with 6-10 Mev protons, 10-20 Mev deuterons, and 15-40 Mev alpha particles. The excitation function for the ${\mathrm{In}}^{115}(\alpha , \alpha n){\mathrm{In}}^{114m}$ reaction has also been obtained. All the excitation functions increase monotonically with energy. The cross sections for the formation of ${\mathrm{In}}^{115m}$ at the highest bombarding energies are 1.5 mb, 42 mb, and 5.2 mb, for the proton-, deuteron-, and alpha-induced reactions, respectively. The corresponding cross sections for the formation of ${\mathrm{Cd}}^{111m}$ are 2-3 times larger. The results have been compared with the predictions of the statistical theory. The only definite conclusion can be drawn in the case of the ($\alpha , \alpha \gamma$) reaction where it is shown that an evaporation mechanism cannot account for the measured cross sections at bombarding energies above 25 Mev. The contribution of Coulomb excitation to the observed yields has been calculated. It is found that this process contributes substantially to the ($\alpha , \alpha \gamma$) and ($p, p\gamma$) reactions, particularly at low bombarding energies.