Analyses of Quasielastic and Quasi-Inelastic (He3,t) Scattering from the Ni Isotopes

Abstract

Differential cross sections for 37.5-MeV (${}_{}{}^3{}_{}{}^{}\mathrm{He}$, $t$) data have been measured for the Ni isotopes. The data are analyzed using a coupled-channels formalism with both macroscopic and microscopic models for the interaction. The distorted-wave Born approximation, however, is found to be a reasonable approximation. The quasielastic scattering (i.e., excitation of the state in Cu which is the analog of the Ni target ground state) is adequately explained by either model and yields the expected $N-Z$ isotopic dependence. A macroscopic description of the quasi-inelastic scattering (i.e., excitation of the $2^{+}$ analog state) requires a large charge-exchange deformation parameter, in disagreement with results obtained at lower energies for ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ti}$. A microscopic description, on the other hand, yields an extracted well depth which is roughly the same for quasielastic and quasi-inelastic scattering. The relative amounts of $f$ and $p$ configuration in the neutron excess are estimated using the microscopic model and are found to be consistent with shell-model calculations.