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

A study of L-3 subshell X-lay production cross-sections and fluorescence yields by using characteristic K X-rays as the exciting radiation is described. Only the L-3 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-1, L-alpha and L-beta groups of L-3 subshell X-rays of Pb, Th iind U have been measured using photoionization by Rb, Nb and Mo K X-rays. The measured Lj X-ray production cross-section values for Pb, Th and U are in good agreement with the theoretical ones evaluated using L-3 subshell fluorescence yield omega(3), fractions of the radiative width F-3i and L-3 subshell photoionization cross-section sigma(3). The L-3 subshell fluorescence yields (omega(3)) have also been computed using the presently measured cross-section values and the theoretical L-3 subshell photoionization cross-section values. These results are compared with the theoretically predicted values. (C) 2000 Elsevier Science B.V. All rights reserved.