We have accurately measured the total-conversion coefficient for the 156.0-keV, $M4\mathrm{}$ transition in ${}_{}{}^{117}{}_{}{}^{}\mathrm{Sn}$ as ${\alpha }_T=46.40\mathrm{}\pm 0.25$. The Hager and Seltzer theoretical value is 47.8. A comparison between experimental and theoretical ${\alpha }_K$ and ${\alpha }_T$ values for 15 $E3\mathrm{}$ and $M4\mathrm{}$ transitions shows that the theoretical values are systematically 2-3% higher.

• Received 12 February 1973

DOI:https://doi.org/10.1103/PhysRevC.7.2531