A.P.L. Bertol

Silver L1, L2 and L3 cross-sections for ionization and x-ray production by electron impact

The experimental determination of ionization cross-sections and total x-ray production crosssections under electron impact is carried out for the three silver L-subshells. The very complex spectral structure involving several satellite bands was previously investigated by analyzing wavelength-dispersive spectra acquired in an electron microprobe. In this work, careful spectral processing is carried out by means of the POEMA software developed previously, considering the spectral energy intervals which include the main Ag-L emissions. The resulting ionization cross-sections are compared with analytical models based on distorted wave Born approximation calculations, the experimental determinations of the present work being underestimated by these predictions. To the best of the authors’ knowledge, this is the first time these magnitudes are reported in the literature in this energy range. The total L-shell x-ray production cross-sections are also compared with the only previous experimental data found, obtained with different experimental settings.

Structure of the Fe and Ni L X-ray spectra

Fe-L and Ni-L X-ray spectra induced by electron impact were analyzed. The measurements were made on bulk samples using a commercial wavelength dispersive spectrometer, and the spectra were processed with a parameter optimization method previously developed. This procedure allowed for the determination of characteristic energies, relative transition probabilities and natural linewidths. The results obtained are compared to the data found in the literature, when available. Satellite and radiative Auger emissions were also analyzed, energy shifts and relative intensities being determined. Many of these parameters were determined for the first time, which was possible due to the robustness of the spectral processing method used. The line profile introduced here takes into account the differential attenuation at both sides of the absorption edge.