We searched for a temperature dependence of the half-life ($T_{1/2}$) of ${}^{64}\mathrm{Cu}$ embedded in natural copper. We did not observe any change in $T_{1/2}$ between room temperature and 12 K on the level of 0.25%. Some earlier studies had suggested an increased $T_{1/2}$ (by a few percent) for electron-capture and ${\beta }^{-}$ decay dominated radioactive decays in a metallic environment at low temperature compared to measurements at room temperature. Our result is in excellent agreement with the recommended $T_{1/2}$ value for ${}^{64}\mathrm{Cu}$ and with very recent studies on ${}^{198}\mathrm{Au}$.

• Received 8 August 2008

DOI:https://doi.org/10.1103/PhysRevC.78.057301