Angular dependence of L x-ray production cross-section in seven elements from Au to U at 59.5 keV photon energy

The Ll, Lalpha, Lbeta and Lgamma x-ray production cross-sections in U, Th, Bi, Pb, Tl, Hg and Au were measured using 59.5 keV incident photon energies in the angular range 40-130degrees. The measurements were performed using the Am-241 radioisotope as photon source and a detection system with an Si(Li) detector. Although differential cross-sections for Lbeta and Lgamma x-rays were found to be angle independent, within experimental error, those for Ll and Lalpha x-rays were found to be angle dependent. This confirms the angular dependence of measured photon induced Ll and Lalpha x-ray production cross-sections as reported by two groups. Further, the present results also confirm the theoretical predictions of two other groups but are contrary to the results reported by others. Integral cross-sections for production of Ll, Lalpha, Lbeta and Lgamma x-rays were also deduced and were found to be in good agreement with the theoretical values. Copyright (C) 2002 John Wiley Sons, Ltd.