Alpha scattering from ²⁰⁹Bi at 50.5 MeV

Abstract

The cross sections for the elastic and inelastic scattering of alpha particles from ²⁰⁹Bi have been measured at 50.5 MeV for angles up to 92° in steps of 1°. An optical model analysis of the elastic scattering data has been made, starting with the parameters predicted from systematics and consistent with those determined at higher energies. The large angular range combined with the relatively small errors in the measurement restrict the real potential to just three discrete families. A nearside-farside decomposition of the data clearly reveals the Fraunhofer diffraction pattern superimposed on the large background of Fresnel diffraction. The inelastic scattering data have been analyzed in terms of the collective model using the distorted wave Born approximation, for which the distorted waves were generated by the optical model analysis of the elastic scattering data. The values of the deformation lengths (βR) obtained are compared with those reported in the literature.