Proton-Nucleus Scattering at 17 Mev

Abstract

Previous studies of proton-nucleus scattering have been extended to 17 Mev. As at 10 Mev, it is difficult to obtain unique sets of parameters because of the similar effects of the real part of the potential $V$ and the interaction radius $R$, on the one hand, and the imaginary part of the potential $W$ and the diffuseness parameter $a$, on the other. If the best half-way radius for each element is expressed as $R=r_0{A}^{\frac{1}{3}}\times {10}^{-13\mathrm{}}$ cm, $r_0$ decreases from $r_0=1.29\mathrm{}$ for light and medium elements to $r_0=1.22\mathrm{}$ for heavy elements. Values for the diffuseness parameter near $a=0.5\mathrm{}\times {10}^{-13\mathrm{}}$ cm are used. Normalized to $r_0=1.30\mathrm{}$ the average value of the optical model potential at this energy is $-(50+i8)\mathrm{}$ Mev. Values of the reaction cross section are given. An analysis of proton-carbon scattering from 14 to 20 Mev is presented. It is also shown that proton-nucleus scattering at this energy is insensitive to the precise details of the potential in the central and surface regions. In addition the scattering is independent of the shape of the nuclear charge density for energies up to 100 Mev.