Parity Measurements in the $^{70}$Ga Nucleus

The odd-odd $^{70}$Ga nucleus was studied at high spin after being produced at Florida State University using the $^{62}$Ni($^{14}$C, $\alpha pn$) fusion-evaporation reaction at a beam energy of 50 MeV. The resulting $\gamma$ rays were detected in coincidence using an array of Compton-suppressed Ge detectors consisting of three Clover detectors and seven single-crystal detectors. The linear polarizations of eight $\gamma$-ray transitions in $^{70}$Ga were measured by comparing their scattering yields within a Clover detector in the parallel and perpendicular directions relative to the beam axis, under the requirement that at least one other $\gamma$ ray in $^{70}$Ga was recorded by a single-crystal detector in the array. As a result of these measurements, the parities of six states were confirmed and those of two other states were established for the first time based on a comparison of the experimental polarizations with the predicted ones determined from known spin assignments. The resulting level spectrum of $^{70}$Ga shows both similarities and differences with the predictions of previous shell-model calculations.