Neutron scattering from the155,156,157,158,160Gdisotopes: Measurements and analyses with a deformed, semimicroscopic optical model

Abstract

Measurements of elastic and inelastic scattering cross sections have been performed for 2.5 and 4.1 MeV neutrons incident on ${}^{155,156,157,158,160}\mathrm{Gd}.$ Angular distributions have been measured at both energies for the ${0}^{+},$ ${2}^{+},$ and ${4}^{+}$ members of the ground-state (gs) band of the even-even isotopes and for the ${3/2}^{\ensuremath{-}},$ ${5/2}^{\ensuremath{-}},$ and ${7/2}^{\ensuremath{-}}$ levels of the gs band of the even-odd isotopes. Angular distributions for inelastic scattering from the ${9/2}^{\ensuremath{-}}$ level of the gs band of ${}^{155}\mathrm{Gd}$ and ${}^{157}\mathrm{Gd}$ have also been measured at 4.1 MeV. These results together with previously measured s- and p-wave strength functions, potential scattering radii, and elemental total cross sections have been combined in an analysis based on coupled-channel semimicroscopic optical model potential (OMP) and statistical model calculations. The deformed OMP, an extension of our earlier work [E. Bauge, J.P. Delaroche, and M. Girod, Phys. Rev. C 48, 1118 (1998)], is built using a complex density-dependent effective interaction and deformed matter densities deduced from unconstrained, axially symmetric Hartree-Fock-Bogoliubov (HFB) calculations based on the Gogny force. The HFB calculations which describe quite nicely a wealth of results from electron scattering and Coulomb excitations measurements, lead to semimicroscopic OMP predictions in good agreement with the neutron scattering and reaction measurements. A phenomenological OMP analysis is also performed to compare the global properties of both potentials.