Decay ofHf172to levels inLu172

Abstract

The electron-capture decay of $^{172}\mathrm{Hf}$ was investigated. Single and coincidence measurements were made by using germanium x-ray detectors. In addition, a Si(Li) detector was used to study the low-energy portion, \ensuremath{\lesssim} 60 keV, of the $\ensuremath{\gamma}$-ray spectrum. These results were then combined with available conversion-electron data which had been obtained with a magnetic spectrometer. From this information, a decay scheme for $^{172}\mathrm{Hf}$ was constructed. It incorporates 17 transitions into 11 excited levels in $^{172}\mathrm{Lu}$ and differs from previously proposed decay schemes. Several transitions previously attributed to $^{172}\mathrm{Hf}$ decay were not observed in the present study. The electron-capture decay energy was deduced from measured $K$ x-ray intensities and the level scheme to be 350\ifmmode\pm\else\textpm\fi{}50 keV.RADIOACTIVITY $^{172}\mathrm{Hf}$, measured ${E}_{\ensuremath{\gamma}}$, ${I}_{\ensuremath{\gamma}}$, ${I}_{x}$, $\ensuremath{\gamma}\ensuremath{\gamma}$ coin; deduced ${Q}_{\mathrm{EC}}$. $^{172}\mathrm{Lu}$ deduced levels ${J}^{\ensuremath{\pi}}$.