Recoil-Distance Lifetime Measurements inTi46andCr50

Abstract

The mean lifetimes of several excited states in the cross-conjugated nuclei ${}_{}{}^{46}{}_{}{}^{}\mathrm{Ti}$ and ${}_{}{}^{50}{}_{}{}^{}\mathrm{Cr}$ were measured with the recoil-distance Doppler-shift method. The levels were fed via the ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}({}_{}{}^{16}{}_{}{}^{}\mathrm{O}, 2p)$ and ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}({}_{}{}^{12}{}_{}{}^{}\mathrm{C}, 2p)$ reactions, respectively, which lead to a strong population of high-spin levels in the residual nuclei. Lifetimes of the ground-state bands up to the $6^{+}$ states were measured in both nuclei. A decrease of the $B\downarrow \mathrm{}\left(E2\mathrm{}\right)\mathrm{}$ values with increasing spin was found.