UraniumMx-ray emission spectrum

Abstract

The uranium $M$ x-ray spectrum from a thick metallic target excited by 12-keV electrons was measured by the PAX (photoelectron spectrometry for the analysis of x rays) technique. Energies of the strongest lines were obtained with an accuracy of 0.1 eV using Ag $L{\beta }_1$ and Ag $L{\alpha }_1$ as standards. Widths of the uranium lines were obtained by deconvoluting the measured Voigt profiles, and the experimental values were found to agree satisfactorily with McGuire's Hartree-Slater predictions. Natural widths of 4.0(3) and 3.8(3) eV were derived for the $M_4$ and $M_5$ levels, respectively, and the energies of the $M_4$, $M_5$, $N_2$, and $N_3$ levels in uranium metal were determined. Relative intensities of the $M$ lines were measured, and branching ratios were found to be in fair agreement with relativistic Hartree-Slater predictions. The satellite structures of the $M{\alpha }_1$ and $M\beta$ lines were interpreted in terms of the pertinent multiple-hole configurations. Finally, an approximate analytic expression for the Voigt half-width and its graphical representation are given.