Conversion Coefficients of Low-Energy Gamma Radiation Following the Decay ofSe81andSe81m

Abstract

A Ge(Li) $\ensuremath{\gamma}$-ray spectrometer and a Si(Li) electron spectrometer were standardized for measurements of internal---conversion coefficients using $\ensuremath{\gamma}$ transitions of well-known ${\ensuremath{\alpha}}_{K}$ and ${\ensuremath{\alpha}}_{L}$ values from standard sources. The internal---conversion coefficients of four $\ensuremath{\gamma}$ transitions in $^{81}\mathrm{Br}$ and one in $^{81}\mathrm{Se}$ have been measured. The results for the conversion coefficients are as follows: $^{81}\mathrm{Se}$, 103 keV: ${\ensuremath{\alpha}}_{K}=7.1\ifmmode\pm\else\textpm\fi{}0.3$, ${\ensuremath{\alpha}}_{L}=1.6\ifmmode\pm\else\textpm\fi{}0.3$; $^{81}\mathrm{Br}$, 178 keV: ${\ensuremath{\alpha}}_{K}<0.05$, ${\ensuremath{\alpha}}_{L}<0.003$; 260 keV: ${\ensuremath{\alpha}}_{K}=0.038\ifmmode\pm\else\textpm\fi{}0.001$, ${\ensuremath{\alpha}}_{L}=0.005\ifmmode\pm\else\textpm\fi{}0.002$; 276 keV: ${\ensuremath{\alpha}}_{K}=0.009\ifmmode\pm\else\textpm\fi{}0.001$, ${\ensuremath{\alpha}}_{L}=0.002\ifmmode\pm\else\textpm\fi{}0.001$; 290 keV: ${\ensuremath{\alpha}}_{K}=0.012\ifmmode\pm\else\textpm\fi{}0.001$, ${\ensuremath{\alpha}}_{L}=0.002\ifmmode\pm\else\textpm\fi{}0.001$. The multipolarities are deduced to a fair degree of certainty.