Redetermination of the Decay Energy ofBa133

Abstract

We have redetermined the $\frac{{L}_{1}}{K}$ electron capture ratio for the decay of ${\mathrm{Ba}}^{133}$ to the 437-keV level of ${\mathrm{Cs}}^{133}$ using a modified version of the sum-coincidence technique. The $L$ and $K$ x-ray intensities following electron capture were measured in coincidence with the 437-keV sum peak arising from the coincidence summing of the 356-81-keV $\ensuremath{\gamma}$ cascade in ${\mathrm{Cs}}^{133}$. The measured $\frac{{L}_{1}}{K}$ ratio of 0.67\ifmmode\pm\else\textpm\fi{}0.15 leads to a decay energy of ${62}_{\ensuremath{-}3.7}^{+6.8}$ keV to the 437-keV level. This value is closer to the recent determination of Schulz than to the earlier ones.