Deformation effects in neutron scattering from the Sm isotopes

Differential cross sections for neutron scattering from four even-$A$ isotopes of Sm have been measured at an incident energy of 7 MeV. Separated isotope samples having enrichments between 87.4 and 99.5% were used, each sample containing about 0.15 moles. Measurements have been separated for elastic and inelastic scattering to the first $2^{+}$ levels of ${}_{}{}^{148}{}_{}{}^{}\mathrm{Sm}$, ${}_{}{}^{150}{}_{}{}^{}\mathrm{Sm}$, and ${}_{}{}^{152}{}_{}{}^{}\mathrm{Sm}$. For ${}_{}{}^{154}{}_{}{}^{}\mathrm{Sm}$ the two processes were not separated. The data show directly the striking effects of the difference in coupling between the $0^{+}$ and $2^{+}$ levels of these transitional nuclei. Accurately measured total cross sections and low energy scattering properties have been combined with these 7 MeV results in a coupled-channel analysis. Coupling parameters extracted from the analysis have been shown to be significantly less than the deformation parameters which characterize the charge distributions of the deformed isotopes.