Evidence for a 0+ State inZn68Populated byGa68

Abstract

The $\gamma$ rays following the decay of ${}_{}{}^{68}{}_{}{}^{}\mathrm{Ga}$ in equilibrium with ${}_{}{}^{68}{}_{}{}^{}\mathrm{Ge}$ have been studied with a 15-cc Ge(Li) detector in conjunction with a 4096-channel analyzer and with a Ge(Li)-NaI(Tl) coincidence arrangement. $\gamma$ rays assigned to the decay of ${}_{}{}^{68}{}_{}{}^{}\mathrm{Ga}$ are as follows (energies in keV, relative intensities in parentheses): 578.3±1.0 (1.1), 805.8±0.6 (2.8), 1077.4±0.2 (100), 1261.3±0.3 (2.9), 1746.4±1.0 (0.28), 1883.5±0.4 (4.1), and 2338±2 (0.4). The observed levels in ${}_{}{}^{68}{}_{}{}^{}\mathrm{Zn}$ are as follows: 1077.4±0.2, 1655.7±1.0, 1883.4±0.3, 2338.7±0.4, and 2823.8±1.0 keV. The 578.3-keV transition and the level at 1655.7 keV it depopulates are previously unreported in the $\beta$ decay of ${}_{}{}^{68}{}_{}{}^{}\mathrm{Ga}$. $\gamma -\gamma$ directional-correlation measurements were carried out with a Ge(Li) detector in one channel. The $A_2$ and $A_4$ coefficients for the 578.3-1077.4-keV cascade were measured to be 0.21±0.14 and 1.35±0.27, respectively. From these results, the 1655.7-keV level is uniquely assigned a spin of 0.