Nuclear deformation in the actinide region by proton inelastic scattering

Elastic and inelastic proton differential cross sections have been measured for ²³²Th and ²³⁹U at incident energies of 20 and 26 MeV. Scattered protons were detected with a split-pole spectrometer using a position sensitive delay-line proportional counter. Proton groups up to the 8⁺ level in the ground state rotational band have been measured. The analysis of the data has been done using coupled-channel calculations for deformed nuclei. We have studied the sensitivity of the calculations to (a) the optical model parameters, (b) the shape of the nuclear charge distribution, (c) the coupling scheme assumed among the levels, and (d) the magnitude and sign (±β₆) of the deformation parameters. The calculated multipole potential moments, obtained from the best fits to the data, agree well with the values deduced from proton measurements at other energies. They are also in good agreement with the values reported from Coulomb excitation and inelastic scattering using α particles and neutron probes.NUCLEAR REACTIONS ²³²Th, ²³⁸U (p,p) (pp^'), $E=26$ MeV; calculated σ(θ); deduced deformation parameters and multipole moments of the potential. Coupled channel analysis.