High-spin states inNb92

Abstract

High-spin states have been investigated with the $^{88}\mathrm{Sr}$($^{7}\mathrm{Li}$,$3n$)$^{92}\mathrm{Nb}$ reaction by $\ensuremath{\gamma}\ensuremath{-}\ensuremath{\gamma}$ coincidence, $\ensuremath{\gamma}$-ray angular distribution, and pulsed beam-$\ensuremath{\gamma}$ timing measurements with Ge(Li) detectors. Decay schemes, level energies, and spin-parity information were obtained for $^{92}\mathrm{Nb}$ from the data. The positive-parity yrast level sequence was established up to a ${13}^{+}$ state at 3326 keV. An ${11}^{\ensuremath{-}}$ isomeric level at 2203 keV was found and observed to have a mean lifetime of $\ensuremath{\tau}=241\ifmmode\pm\else\textpm\fi{}5$ nsec. The $g$ factor of this isomer was measured to be $g=0.88\ifmmode\pm\else\textpm\fi{}0.03$. The observed properties of levels in $^{92}\mathrm{Nb}$ are compared with shell-model calculations.NUCLEAR REACTIONS $^{88}\mathrm{Sr}$($^{7}\mathrm{Li}$,$3n$), ${E}_{\mathrm{Li}}=34$ MeV; measured $\ensuremath{\gamma}\ensuremath{-}\ensuremath{\gamma}$ coin, $\ensuremath{\gamma}(E,\ensuremath{\theta},t)$, spin rotation in $B=11.2$ kG; deduced level scheme in $^{92}\mathrm{Nb}$, $\ensuremath{\gamma}$ multipolarities, ${T}_{\frac{1}{2}}$,${J}^{\ensuremath{\pi}}$, $g$ factor. Natural target, Ge(Li) detectors.