Analysis ofγ−γCascades by Polarization and Directional Correlation: Decay ofRh101g

Abstract

A procedure is given for using the results of polarization-direction correlation and directional-correlation measurements to analyze $\ensuremath{\gamma}\ensuremath{-}\ensuremath{\gamma}$ cascades in cases in which both transitions may be of mixed multipole order. A method is also presented for obtaining polarization-direction correlation coefficients from the measured rates via a Monte Carlo program based on Compton-scattering theory. The methods were applied to the 198-127-keV $\ensuremath{\gamma}\ensuremath{-}\ensuremath{\gamma}$ cascade in ${\mathrm{Ru}}^{101}$ populated by the decay of ${\mathrm{Rh}}^{101g}$. It was determined that the spin of the 127-keV state is $\frac{3}{2}$ and the spin of the 325-keV state is ${\mathrm{\textonehalf{}}}^{+}$. The $\frac{E2}{M1}$ mixing ratio is 0.17\ifmmode\pm\else\textpm\fi{}0.04 for the 127-keV transition and -0.12\ifmmode\pm\else\textpm\fi{}0.03 for the 198-keV one. Relative $\ensuremath{\gamma}$-ray intensities of 94, 100, and 21, respectively, were found for the 127-, 198-, and 325-keV transitions. In a triple-coincidence scintillation-counter measurement, the $K$ internal-conversion coefficient of the 127-keV transition was found to be 0.16\ifmmode\pm\else\textpm\fi{}0.02.