Inelastic neutron scattering studies of Se76

Abstract

The low-lying, low-spin levels of $^{76}\mathrm{Se}$ were studied with the $(n,{n}^{\ensuremath{'}}\ensuremath{\gamma})$ reaction. Gamma-ray excitation function measurements were performed at incident neutron energies from 2.0 to 3.5 MeV, and $\ensuremath{\gamma}$-ray angular distributions were measured at neutron energies of 2.4, 3.0, and 3.7 MeV. From these measurements, level spins, level lifetimes, branching ratios, and multipole mixing ratios were determined. We established the ${0}_{2}^{+}$ band, which supports the shape coexistence in $^{76}\mathrm{Se}$ predicted by large-scale shell model calculations and the interacting boson model.