L2,3-subshell x-ray fluorescence and Coster-Kronig yields atZ=64 and 67

The total Coster-Kronig transition probability $f_{23}$ for the $L_2-L_3$ transition and the $L_2$ and $L_3$ subshell x-ray fluorescence yields ${\omega }_2$ and ${\omega }_3$ were measured utilizing resolved $L-K$ x-ray coincidence techniques for $Z=64\mathrm{} \mathrm{and} 67$ with radioactive sources of 4.68 yr ${}_{}{}^{155}{}_{}{}^{}\mathrm{Eu}$ and 10.4 h ${}_{}{}^{165}{}_{}{}^{}\mathrm{Er}$, respectively. Improved accuracy in the results is achieved by advances in the experimental method. The values of $f_{23}$ are 0.130±0.012 and 0.115±0.011 at $Z=64\mathrm{} \mathrm{and} 67$, respectively, and of ${\omega }_2$ and ${\omega }_3$ are 0.165±0.022 and 0.161±0.019 at $Z=64\mathrm{}$, and 0.186±0.023 and 0.180±0.020 at $Z=67\mathrm{}$, respectively. The quoted uncertainties are twice the average deviation from the mean of 12 values of $f_{23}$ and two values each of ${\omega }_2$ and ${\omega }_3$, and arise predominantly from systematic errors.