Determination of L3 subshell X-ray production cross-sections and fluorescence yields of Pb, Th and U

A study of L₃ subshell X-ray production cross-sections and fluorescence yields by using characteristic K X-rays as the exciting radiation is described. Only the L₃ subshells of Pb, Th and U were excited by the characteristic K X-rays of the elements used as secondary sources. The cross-sections for the production of L_l, L and L_β groups of L₃ subshell X-rays of Pb, Th and U have been measured using photoionization by Rb, Nb and Mo K X-rays. The measured L₃ X-ray production cross-section values for Pb, Th and U are in good agreement with the theoretical ones evaluated using L₃ subshell fluorescence yield ω₃, fractions of the radiative width F_3i and L₃ subshell photoionization cross-section σ₃. The L₃ subshell fluorescence yields (ω₃) have also been computed using the presently measured cross-section values and the theoretical L₃ subshell photoionization cross-section values. These results are compared with the theoretically predicted values.