We have obtained proton nonelastic cross sections at 10 MeV from Be, C, Al, Ti, Mo, Zr, Fe, Ni, Zn, Cu, V, Rh, Nb, Ag, Sn, Ta, Th, Au, and Pb. The most significant feature of the data is the appearance of two strong minima in the elements lighter than Cu. The data are compared with optical-model predictions. These calculations predict the right order for the reaction cross section when a surface absorption potential that fits existing elastic-scattering data is used. However, on the basis of our data, a volume absorption potential of the Woods-Saxon shape cannot be excluded. The data are compared with other measurements of non-elastic cross sections for 10-MeV protons.

• Received 4 October 1962

DOI:https://doi.org/10.1103/PhysRev.129.2198