10-Mev Proton Reaction Cross Sections Compared with Surface and Volume Absorption Optical Models of the Nucleus

($p, n$) cross sections were measured at 9.85 Mev for self-supporting thin targets of Al, Ti, Fe, Co, Ni, ${\mathrm{Cu}}^{63}$, ${\mathrm{Cu}}^{65}$, Rh, Ag, Sn, Ta, and Au. ($p, 2n$) contributions were calculated using the statistical model of the nucleus for Rh, Ta, Ag, and Au. Charged-particle emission was assumed negligible in Ta and Au because of small Coulomb penetrabilities. Approximate proton reaction cross sections were obtained by adding ($p, n$) and ($p, 2n$) cross sections to ($p, p^{\prime }$) and ($p, \alpha$) cross sections previously reported by Meyer and Hintz. These results were compared with volume absorption and surface absorption optical-model calculations of proton reaction cross sections. The parameters for both model calculations were obtained prior to this work by fitting proton elastic scattering and polarization data. The results indicate a surface-absorption potential rather than a volume-absorption potential.