Proton-Nucleus Elastic Scattering at 9.8 Mev

The differential cross section for proton-nucleus elastic scattering has been measured for Li, N, Al, A, Ni, Cu, Ag, Sn, and Au at a laboratory proton energy of 9.8 Mev. Data were taken at 5° intervals from 15° to 170° with an estimated standard deviation of 3 to 5%. The 24-inch-diameter scattering chamber is described. The protons are detected by a NaI(Tl) crystal whose energy resolution was about 2.5% so that in almost all cases inelastic protons were rejected. The data for Al, A, Ni, Cu, Sn, and Au have been analyzed by using the optical model with the Saxon potential. Good fits are obtained for a radius constant $r_0=1.20\mathrm{}$ in the formula $R=r_0{A}^{\frac{1}{3}}\times {10}^{-13\mathrm{}}$ cm and a real well depth of 62 Mev for most elements. The imaginary well depth and the smoothing parameter are $A$-dependent. A brief discussion is given on the determination of nuclear radii from elastic scattering and nuclear reaction cross sections.