High-Resolution Measurements of Internal Conversion Lines inW183

Abstract

Multipole mixing ratios have been determined for 30 gamma transitions observed in ${\mathrm{W}}^{183}$. These transitions were studied from the beta decay of 5.2-day ${\mathrm{Ta}}^{183}$ using a high-resolution $\sqrt{2}\pi$ iron-free beta spectrometer. In all but seven cases, mixing ratios were determined from $L$-subshell internal-conversion intensities. These mixing ratios are compared with the recent theoretical predictions of Brockmeier et al. and Rowe, and provide a sensitive test of the nuclear models employed in these analyses. No evidence was found for the existence of two recently reported ${\mathrm{W}}^{183}$ transitions. The existence of a new level in ${\mathrm{W}}^{183}$ at 595.33 keV is proposed.