A half-life of 0.55 ± 0.02 s was measured for the neutron-rich fission-product nucleus ${}_{30}{}^{80}{}_{}{}^{}\mathrm{Zn}_{50}^{}{}_{}{}^{}$. A $Q_{\beta }$ value for the decay of ${}_{}{}^{80}{}_{}{}^{}\mathrm{Zn}$ of 7.15 ± 0.15 MeV and a level scheme for ${}_{}{}^{80}{}_{}{}^{}\mathrm{Ga}$ have also been deduced. The properties of this $N=50\mathrm{}$ waiting-point nucleus are significant for the evaluation of different models of $r$-process environments and exposure times.

• Received 12 February 1986

DOI:https://doi.org/10.1103/PhysRevLett.56.1874