The decays of 2.4-min ${}_{}{}^{60}{}_{}{}^{}\mathrm{Zn}$ and 9.3-h ${}_{}{}^{62}{}_{}{}^{}\mathrm{Zn}$ have been investigated with the use of Ge(Li) and NaI(Tl) $\gamma$-ray detectors. Coincidence relationships among the $\gamma$ rays were determined in $\gamma -\gamma$ coincidence experiments. It was established that the decay of 2.4-min ${}_{}{}^{60}{}_{}{}^{}\mathrm{Zn}$ populates levels at 61.4, 334.4, 364.6, 572.4, and 669.7 keV in ${}_{}{}^{60}{}_{}{}^{}\mathrm{Cu}$, and the decay of 9.3-h ${}_{}{}^{62}{}_{}{}^{}\mathrm{Zn}$ populates levels at 40.84, 243.43, 287.86, 548.25, and 637.20 keV in ${}_{}{}^{62}{}_{}{}^{}\mathrm{Cu}$. Many spin assignments have been made from present $log\mathrm{ft}$ values, previously reported conversion-electron data, and spectroscopic studies from nuclear reactions. The half-life of ${}_{}{}^{60}{}_{}{}^{}\mathrm{Zn}$ was measured to be 2.42±0.02 min. The fraction of $\beta$ decay (positron plus electron capture) of ${}_{}{}^{62}{}_{}{}^{}\mathrm{Zn}$ to the ground state of ${}_{}{}^{62}{}_{}{}^{}\mathrm{Cu}$ was measured to be 0.43±0.05; the ratio of positron to $K$ capture for the same decay was measured to be 0.22±0.01.

• Received 12 August 1968

DOI:https://doi.org/10.1103/PhysRev.177.1640