Component analysis and correction of characteristic X-ray yields in the measurement of keV electron-impact atomic inner-shell ionization cross-sections using the thick target method

Inverting cross-sections from thick-target characteristic X-ray yields is an ill-posed inverse problem. Some studies have calculated cross-sections using analytical formulas that ignore the contributions of electron scattering effects, secondary electrons, and bremsstrahlung, without correcting the experimental yields. In this work, simulations were performed for electrons with energies below 30 keV incident on thick Si, Zr, Ag, and W targets at angles of 45° and 90° relative to the target surface, and the sources and relative contributions to the characteristic X-ray yields were analyzed for the Si and Zr K-shells, the Ag L-shell, and the W L αβγ lines. This paper also processed the aforementioned corrected experimental yields for thick targets using the numerical-neural network method to obtain reliable cross-sections. These results were compared with DWBA theoretical values and cross-sections inverted from uncorrected literature yields using the Tikhonov regularization method; the maximum deviation reached 14%, indicating the necessity of yield correction.