Angular dependence of<i>L</i>x-ray production cross sections in uranium at 22.6- and 59.5-keV photon energies

Abstract

The Ll, $L\ensuremath{\alpha},$ $L\ensuremath{\eta},$ $L{\ensuremath{\beta}}_{6},$ $L{\ensuremath{\beta}}_{2,4},$ $L{\ensuremath{\beta}}_{1,3},$ $L{\ensuremath{\beta}}_{9,10},$ and $L\ensuremath{\gamma}$ x-ray production differential cross sections in ${}_{92}\mathrm{U}$ have been measured using the 22.6- and 59.5-keV incident photon energies in an angular range 43\ifmmode^\circ\else\textdegree\fi{}--140\ifmmode^\circ\else\textdegree\fi{}. The measurements were performed using the ${}^{109}\mathrm{Cd}$ and ${}^{241}\mathrm{Am}$ radioisotopes as photon sources and a Si(Li) detector. 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 measured photon-induced Ll and $L\ensuremath{\alpha}$ x ray production cross sections as reported by Kahlon et al. [Phys. Rev. A 43, 1455 (1991)] and M. Ertugrul [Nucl. Instrum. Methods Phys. Res. B 119, 345 (1996)]. Integral cross sections for production of the Ll, $L\ensuremath{\alpha},$ $L\ensuremath{\eta},$ $L{\ensuremath{\beta}}_{6},$ $L{\ensuremath{\beta}}_{2,4},$ $L{\ensuremath{\beta}}_{1,3},$ $L{\ensuremath{\beta}}_{9,10},$ $L{\ensuremath{\gamma}}_{1,5},$ $L{\ensuremath{\gamma}}_{2,3,6},$ and $L{\ensuremath{\gamma}}_{4}$ x rays are also deduced in the present paper and are found to be in good agreement with those evaluated using the most reliable theoretical values of ${L}_{i}$ $(i=1,2,3)$ subshell photoionization cross sections, fluorescence yields, x-ray emission rates, and Coster-Kronig transition probabilities.