Lifetimes Within the 73Se Nucleus

There is considerable uncertainty in the literature regarding the cascade intensities of the decay sequences in $^{73}$Se. In particular, the degree to which each state is populated by side feeding can vary considerably. The goal of this work was to measure as many lifetimes as possible in $^{73}$Se by gating from above the transition of interest in order to eliminate the effects of uncertainties in side feeding intensities. This was made possible by the excellent $\gamma$-ray counting statistics for $^{73}$Se provided by the $^{14}$C($^{62}$Ni, 3$n$) reaction performed at Florida State University using a beam energy of 50 MeV and with a Compton-suppressed Ge detector array consisting of 3 Clover detectors and 7 single-crystal detectors. The Doppler-shift attenuation method was used to measure all lifetimes. Seven lifetimes were measured, four within the strongest positive-parity band and three within the favored negative-parity band. From these lifetimes the quadrupole deformation parameter $\beta_2$ could be inferred and compared with those predicted for these states as a function of spin. In general, the experimental trends were not reproduced in the calculations.