Lifetime measurements inNb93from photon and inelastic neutron scattering

Abstract

The low-spin structure of $^{93}\mathrm{Nb}$ has been studied using the $^{93}\mathrm{Nb}$$(\ensuremath{\gamma},{\ensuremath{\gamma}}^{'})$, $^{93}\mathrm{Nb}$$(n,{n}^{'}\ensuremath{\gamma})$ and $^{94}\mathrm{Zr}$$(p,2n\ensuremath{\gamma}\ensuremath{\gamma})$$^{93}\mathrm{Nb}$ reactions. Lifetimes were determined from both $^{93}\mathrm{Nb}$$(\ensuremath{\gamma},{\ensuremath{\gamma}}^{'})$ and $^{93}\mathrm{Nb}$$(n,{n}^{'}\ensuremath{\gamma})$ measurements. Branching ratios were measured, and multipolarities and spin assignments were determined from the $^{94}\mathrm{Zr}$$(p,2n\ensuremath{\gamma}\ensuremath{\gamma})$$^{93}\mathrm{Nb}$ angular correlation experiment. From $M1$ and $E2$ strengths, the ${J}^{\ensuremath{\pi}}=9/{2}^{+}$ and $7/{2}^{+}$ states at 1297.1 keV and 1483.6 keV, respectively, are proposed as members of the quintet of mixed-symmetry states associated with the $\ensuremath{\pi}1{g}_{9/2}\ensuremath{\bigotimes}({2}_{1,\mathrm{MS}}^{+}$,$^{92}\mathrm{Zr}$) configuration. The large $B(M1)$ values determined in $^{93}\mathrm{Nb}$ cannot be explained within the weak coupling limit of the interacting boson fermion model.