Transition Mixing Ratios Determined from a Study of the Electron and Gamma-Ray Distributions from OrientedIr192

The angular distributions measured for 12 $\gamma$ rays in ${}_{}{}^{192}{}_{}{}^{}\mathrm{Os}$ and ${}_{}{}^{192}{}_{}{}^{}\mathrm{Pt}$ resulting from the decay of cryogenically oriented ${}_{}{}^{192}{}_{}{}^{}\mathrm{Ir}$ have been used to determine the following $\frac{E2\mathrm{}}{M1\mathrm{}}$ mixing ratios: 201 keV, ${\delta }^2>3.7\mathrm{}$; 296 keV, $\delta =-\left(6_{-1\mathrm{}}^{+3\mathrm{}}\right)$; 308 keV, $\delta =-(7.1\mathrm{}\pm 0.6)$; 417 keV, $\delta =4_{-3\mathrm{}}^{+7\mathrm{}}$; 485 keV, $\delta =5.8\mathrm{}\pm 0.8$; 604 keV, $\delta =1.5\mathrm{}\pm 0.1$, following the Rose-Brink sign convention. The angular distribution of the 672-keV $\beta$ group and the above $\gamma$ measurements limit the relative contribution, $I_L$, of different operator tensor ranks, $L$, involved in each $\beta$ transition. The results for electron-capture transitions terminating at levels in osmium are: 694-keV level, $I_1>0.9\mathrm{}$; 584-keV level, $I_0>0.6\mathrm{}$, $I_2<0.1\mathrm{}$. For $\beta$ transitions feeding platinum states, we determine: 921-keV level, $I_1>0.8\mathrm{}$; 785-keV level, $I_1>0.92\mathrm{}$, $I_2<0.03\mathrm{}$. The ${}_{}{}^{192}{}_{}{}^{}\mathrm{Ir}$ ground-state magnetic moment is determined to be positive.