Internal Conversion Coefficients in the Decay ofAu199

The intensities of the $\gamma$ rays and electron shell vacancies in the decay of ${\mathrm{Au}}^{199}$ have been measured by differential $\gamma$-ray spectrometry and $4\pi$ $\beta -\gamma$ coincidence counting. These intensities, per ${\mathrm{Au}}^{199}$ disintegration, are 0.368±0.011, 0.0774±0.0022, and 0.0031±0.0015 for the 0.158-, 0.209-, and 0.051-MeV $\gamma$ rays, respectively, and 0.208±0.014 and 0.176±0.005 for the $L$- and $K$-shell vacancies, respectively. Internal conversion coefficients, obtained from these data and the relative conversion electron yields of Nall, Baird, and Haynes, are: in the $K$ shell, 0.317±0.013 and 0.768±0.032 for the 0.158- and 0.209-MeV $\gamma$ rays, respectively; and in the $L$ shell, 0.464±0.039, 0.139±0.012, and 8.5±4.1 for the 0.158-, 0.209-, and 0.051-MeV $\gamma$ rays, respectively. These values are consistent with the internal conversion coefficients calculated by Rose. The intensities computed from the data for the 0.251-, 0.302-, and 0.460-MeV $\beta$-particle transitions are 0.189±0.005, 0.680±0.025, and 0.131±0.025, respectively.