Measure ofK-Shell Internal Conversion Coefficients with a Coincidence Scintillation Spectrometer

The $K$-shell internal conversion coefficients of gamma rays from ${\mathrm{Te}}^{123}$, ${\mathrm{Sm}}^{153}$, ${\mathrm{Hf}}^{181}$, and ${\mathrm{Os}}^{191}$ have been measured using a coincidence scintillation spectrometer employing NaI and anthracene phosphors as detectors. In several cases an unambiguous classification of the transition as to multipole order and character is possible. The results indicate that the 159-kev gamma ray from ${\mathrm{Te}}^{123}$ is predominantly $M1\mathrm{}$, the 70-kev gamma ray from ${\mathrm{Sm}}^{153}$ is a mixture of $E2+M1\mathrm{}$, the 132-kev gamma ray from ${\mathrm{Hf}}^{181}$ is predominantly $E2\mathrm{}$, the 135-kev gamma ray from ${\mathrm{Hf}}^{181}$ is predominantly $M1\mathrm{}$, the 345-kev and 480-kev gamma rays from ${\mathrm{Hf}}^{181}$ are a mixture of either $E2+M1\mathrm{}$ or $E1+M2\mathrm{}$, and the 129-kev gamma ray from ${\mathrm{Os}}^{191}$ is a mixture of either $E2+M1\mathrm{}$ or $E1+M2\mathrm{}$.