L-X-RAY FLUORESCENCE CROSS-SECTIONS IN THE ATOMIC REGION 46-LESS-THAN-Z-LESS-THAN-51 EXCITED BY 6.47, 7.57 AND 8.12 KEV PHOTONS

Total L X-ray fluorescence cross sections have been measured for the elements Sb, Sn, In, Cd, Ag and Pd excited by 6.47, 7.57 and 8.12 keV photons. The measurements have been performed using an X-ray tube with a modified secondary exciter system as the excitation source. In order to improve the efficiency of the detection system, the excitation source, detector and the target assembly were placed in a vacuum chamber. The measurements were made at a pressure of 10(-2) mbar. The present system considerably reduces the scattering and background effects and improves the monochromaticity. The experimental results have been compared with the theoretical values evaluated using L-subshell fluorescence yields (omega(i)) and Coster-Kronig transition probabilities (f(ij)) based on relativistic Dirac-Hartree-Slater (RDHS) theory. It is observed that the L X-ray cross-section values for the elements in the region are in good agreement with the theoretical values based on RDHS theory. The average L-shell fluorescence yields have also been computed using the experimentally measured cross-section values and the theoretical photoionization cross sections. The average fluorescence yields have been compared with the available results in the literature.