L fluorescence 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 gammas from the decay of these nuclides produces approximately equal numbers of LII and LIII vacancies and practically no LI vacancies; the yields reported here are, therefore, averages of the LII and LIII 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.