Study of Some Properties of Tin Isotopes Through High-Energy Alpha-Particle Scattering

Angular distributions of 166-MeV $\alpha$ particles scattered from the Sn isotopes 116, 118, 120, and 124 have been measured. An analysis of the elastic scattering data was performed using an optical potential calculated from an effective interaction between the $\alpha$ particle and a nuclear-matter distribution. The variation of nuclear sizes among the isotopes is considered. Assuming charge densities derived from the results of elastic electron scattering and/or mesonic atom data, values of neutron-matter radii for the tin isotopes are deduced which agree well with theoretical values. An analysis of the inelastic $\alpha$-particle scattering to the first $2^{+}$ and $3^{-}$ levels for each isotope was effected using the optical potentials calculated from the elastic scattering, the distorted-wave Born-approximation, and quasiparticle wave functions for the excited states. Electromagnetic transition rates and form factors for electron scattering were calculated with the same wave functions, and a comparison of the calculations to the experimental results provides information about the proton and neutron configurations in these isotopes.