Half-life of the electron-capture decay ofRu97: Precision measurement shows no temperature dependence

Abstract

We have measured the half-life of the electron-capture (ec) decay of $^{97}\mathrm{Ru}$ in a metallic environment, both at low temperature $(19 \mathrm{K})$, and also at room temperature. We find the half-lives at both temperatures to be the same within $0.1%$. This demonstrates that a recent claim that the ec decay half-life for $^{7}\mathrm{Be}$ changes by $0.9%\ifmmode\pm\else\textpm\fi{}0.2%$ under similar circumstances certainly cannot be generalized to other ec decays. Our results for the half-life of $^{97}\mathrm{Ru}$, $2.8370(14)$ d at room temperature and $2.8382(14)$ d at $19$ K, are consistent with, but much more precise than, previous room-temperature measurements. In addition, we have also measured the half-lives of the ${\ensuremath{\beta}}^{\ensuremath{-}}$-emitters $^{103}\mathrm{Ru}$ and $^{105}\mathrm{Rh}$ at both temperatures, and found them also to be unchanged.