$L_2$-Subshell Yield Measurements in ${\mathrm{Pu}}^{240}$, ${\mathrm{U}}^{236}$, and ${\mathrm{U}}^{234}$

The fluorescence, Auger, and Coster-Kronig yields of the $L_2$ subshells in ${\mathrm{Pu}}^{240}$, ${\mathrm{U}}^{236}$, and ${\mathrm{U}}^{234}$ have been determined from measurements on $L$ x-rays emitted following $\alpha$ decay of ${\mathrm{Cm}}^{244}$, ${\mathrm{Pu}}^{240}$, and ${\mathrm{Pu}}^{238}$. The techniques employed include $\alpha -L$ x-ray coincidence counting using a silicon detector and NaI(Tl) crystal, proportional-counter spectrometry and in the case of ${\mathrm{Pu}}^{238}$, the use of a curved-crystal spectrograph. The following results were obtained: ${\mathrm{Pu}}^{240}$, ${\omega }_2=0.466\mathrm{}\pm 0.023$, $a_2=0.11\mathrm{}\pm 0.08$, $f_{23}=0.42\mathrm{}\pm 0.08$; ${\mathrm{U}}^{236}$, ${\omega }_2=0.535\mathrm{}\pm 0.042$, $a_2=0.09\mathrm{}\pm 0.11$, $f_{23}=0.37\mathrm{}\pm 0.07$; ${\mathrm{U}}^{234}$, ${\omega }_2=0.497\mathrm{}\pm 0.035$, $a_2=0.07\mathrm{}\pm 0.07$, $f_{23}=0.43\mathrm{}\pm 0.06$. The measured fluorescence yields show close agreement with those calculated on a semiempirical basis by Listengarten, but the Auger and Coster-Kronig yields are, respectively, much smaller and much larger than predicted.