LFluorescence Yields in Heavy Elements

$L$ x-ray fluorescence yields for the Ra, Th, U, Pu, and Cm daughters of even-even alpha emitters were measured by three methods. Internal conversion of $E2\mathrm{}$ gammas from the decay of these nuclides produces approximately equal numbers of $L_{\mathrm{II}}$ and $L_{\mathrm{III}}$ vacancies and practically no $L_{\mathrm{I}}$ vacancies; the yields reported here are, therefore, averages of the $L_{\mathrm{II}}$ and $L_{\mathrm{III}}$ shell yields. The results are: Ra, 0.480±0.012; Th, 0.488±0.008; U, 0.478±0.009; Pu, 0.540±0.009; and Cm, 0.531±0.010.