Alpha inelastic scattering by 208Pb near the Coulomb barrier

Abstract

Elastic scattering of 23.5 MeV α-particles by 208Pb and inelastic scattering to the 3 − state at 2.62 MeV have been measured. Good fits to the data using either the conventional deformed potential or folding-model descriptions of the interaction could be obtained, provided that the distorting potential and inelastic form factor were derived consistently. It was also found necessary to include an energy dependence in the imaginary potential. Both the EM transition rate and the tail of the nuclear form factor are well determined. They are consistent with equal proton and neutron deformation parameters for the 3 − state, although these latter quantities are model dependent and not strictly comparable. The isoscalar transition rate is poorly determined. In terms of the folding-model description, surface distributions of the nuclear matter and transition densities were derived which are in excellent agreement with theoretical calculation.