Determination of environmental dependence of the $\beta^{-}$ decay half-life of $^{198}$Au

A series of articles by the C. Rolfs group [1] claimed changes in the half-lives of isotopes undergoing $\alpha $, $\beta ^{-}$, $\beta ^{+}$, and electron-capture decays as the temperature reduced to 12 K from room temperature. These isotopes were contained in metallic, conductive environments, such as Au, Cu, and Pd, but it was also suggested that the half-life is different in an insulator. One publication [1] reported the half-life of $^{198}$Au in a gold metal environment to change by 3.6 $\pm $1.0{\%} between room temperature and 12 K. Until then, radioactive half-lives were considered independent of environmental factors. We repeated the measurements of the $^{198}$Au half-life in a gold metal environment under similar conditions as ref. [1] and demonstrated [2] that the half-life is the same at both temperatures within 0.04{\%}, two orders of magnitude below the original claims. In the experiment reported here, we measured the half-life of $^{198}$Au in an insulated environment -- gold (III) oxide -- at room temperature. Preliminary results indicate there is no difference in the measured half-life in an insulator as compared in a conductor. \\[4pt] [1] T. Spillane \textit{et al}, Eur. Phys. J. A 31, 203 (2007) \\[0pt] [2] J.R. Goodwin \textit{et al}, Eur. Phys. J. A 34, 271 (2007)