Photon-induced L X-ray production differential cross sections in thorium at 22.6 keV

Abstract

The Ll, Lα, Lβ 2,4, Lβ 1,3 and Lγ 1,5 X-ray production differential cross sections in 90Th have been measured at 22.6 keV incident photon energy in an angular range 50–130°. The measurements were performed using a 109Cd annular-source and a Si(Li) detector. The measured differential cross sections for various L X-rays are found to be angle-independent within experimental error. This is contrary to the strong angular-dependence of photon-induced Ll and Lα X-ray production cross sections as reported by Kahlon et al. (K.S. Kahlon, H.S. Aulakh, N. Singh, R. Mittal, K.L. Allawadhi, B.S. Sood, Phys. Rev. A 43 (1991) 1455) and Ertugrul (M. Ertugrul, Nucl. Instr. and Meth. B 119 (1996) 345). Integral cross sections for production of Ll, Lα, Lη, Lβ 6, Lβ 2,4, Lβ 1,3, Lβ 9,10, Lγ 1,5 and total Lγ X-rays are also deduced and are found to be in good agreement with those calculated using reliable theoretical values of the L i ( i=1, 2, 3) subshell photoionisation cross sections, fluorescence yields, X-ray emission rates and Coster–Kronig transition probabilities.