Elastic scattering of 10.5- and 14.5-MeV polarized protons from nuclei and the optical model potential at intermediate energies

Abstract

The results of extensive measurements of the angular distributions and azimuthal asymmetries for elastic scattering of 10.5 and 14.5 MeV polarized protons, from a wide range of nuclei, are presented. Attention is focused on the general features of these angular distributions and certain deviations from the general trends. The interpretations of both these aspects of the data are discussed. In addition, results are presented from an extensive search program designed to obtain fits to the data with a six-parameter local “optical” potential. From these individual fits to each nuclide have been obtained a set of average parameters at 10.5 MeV and another set at 14.5 MeV. The predictions of the optical model with the average parameters are compared not only to the polarization data but also to elastic differential cross sections and reaction cross sections for protons. With a modification of the magnitudes of the refractive and absorptive central potentials, as required to fit 14.5 MeV neutron elastic scattering cross sections, the potential has been used to predict differential elastic cross sections, reaction cross sections, total cross sections, and polarizations for neutrons, and the results compared with available experimental data. A study has been made of the dependence of the refractive central potential depth on proton energy and on the nuclear symmetry parameter, (N−Z) A , obtaining reasonable agreement with the results of other workers.