Half-lives of Au, Hg, and Pb isotopes from photoactivation

Abstract

The ground state half-lives of the gold isotope ${}^{196}\mathrm{Au},$ the mercury isotopes ${}^{195,197,203}\mathrm{Hg},$ the lead isotope ${}^{203}\mathrm{Pb},$ and the half-lives of two isomers in ${}^{199}\mathrm{Hg}$ and ${}^{204}\mathrm{Pb}$ have been measured with high precision using the photoactivation technique. The $\ensuremath{\gamma}$-ray activity was counted over several half-lives with high-purity germanium detectors. The measured half-lives are: ${T}_{1/2}{(}^{196}\mathrm{Au})=6.1669\ifmmode\pm\else\textpm\fi{}0.0006$ d; ${T}_{1/2}{(}^{195}\mathrm{Hg})=10.53\ifmmode\pm\else\textpm\fi{}0.03$ h; ${T}_{1/2}{(}^{197}\mathrm{Hg})=64.94\ifmmode\pm\else\textpm\fi{}0.07$ h; ${T}_{1/2}{(}^{203}\mathrm{Hg})=46.6\ifmmode\pm\else\textpm\fi{}0.1$ d; ${T}_{1/2}{(}^{204}\mathrm{Pb})=51.95\ifmmode\pm\else\textpm\fi{}0.01$ h; ${T}_{1/2}{(}^{199m}\mathrm{Hg})=42.67\ifmmode\pm\else\textpm\fi{}0.09$ min; ${T}_{1/2}{(}^{204m}\mathrm{Pb})=1.14\ifmmode\pm\else\textpm\fi{}0.04$ h.