The Radiations from 2.7-DayAu198

Abstract

The radiations from the 2.7-day ${\mathrm{Au}}^{198}$ activity were investigated with a counter and photographically recording beta-ray spectrometer. The shape of the continuous beta-ray spectrum is essentially that of an allowed spectrum with some additional intensity in the region below 0.6 Mev. The maximum energy of the spectrum is 0.966\ifmmode\pm\else\textpm\fi{}0.010 Mev. Very strong conversion lines are observed from a gamma-ray of 0.408\ifmmode\pm\else\textpm\fi{}0.004 Mev, and weak conversion lines attributed to gamma-rays of 0.157\ifmmode\pm\else\textpm\fi{}0.002 and 0.208\ifmmode\pm\else\textpm\fi{}0.002 Mev were detected. These weak lines and the deviation of the spectrum from the theoretically permissable spectra suggest that the beta-ray spectrum may be complex with a component of 0.601\ifmmode\pm\else\textpm\fi{}0.016 Mev maximum energy occurring in 15 percent, or less, of the disintegrations. This suggested mode of decay is consistent with the theoretical analysis of the spectrum and half-life. In terms of this theory the 0.966-Mev transition is described by the polar-vector or pseudo-scalar interaction corresponding to a nuclear spin change of \ifmmode\pm\else\textpm\fi{}1, with no parity change.