Measurements of L-l, L-alpha, L-eta, L-beta and L-gamma X-ray fluorescencecross-sections in 70 <= Z <= 92 elements excited by 59.543 keV photons

L-i, L-x, L-eta, L-beta and L-gamma X-ray fluorescence cross-sections have been measured for the elements Yb, Lu, W, Hg, Tl, Pb, Bi and U using excita tion energy of 59.543 keV. Measurements have been performed using an Am-241 annular source and a Si(Li) detector. The experimental values of the cross -sections were determined by measuring the absolute yield of L subshell X-r ays emitted from a standard target of a given element irradiated with photo ns of given energy. The theoretical values of the cross-sections were calcu lated using theoretically tabulated values of subshellphotoionization cross -sections, fluorescence yields, Coster-Kronig transition probabilities and radiative decay rates. Experimental results have been compared with the the oretically calculated values of L X-ray cross-sections. A fairly good agree ment is obtained between the experimental and the calculated values. (C) 20 01 Elsevier Science Ltd. All rights reserved.