Angular dependence of Ag L-X-rays emission induced by 20–40 keV electron-impact

Abstract In element analysis of materials, whether the X-ray emission is isotropic plays an import role in the technique of Particle Induced X-ray Emission (PIXE). Thus, it is meaningful to investigate the alignment of vacancy states produced by impact ionization. In this work, the emission of L X-rays for Ag has been measured by electrons at 20–40 keV. In order to study the angular distribution, the characteristic spectra are detected at different emission angles (from 5° to 25° with intervals of 5°). It is found that the emission of L β1 (L 2 M 4 ) and L γ1 (L 2 N 4 ) X-rays exhibits isotropic distribution, while the emission of L α (L 3 M 4,5 ) and L β2 (L 3 N 5 ) X-rays is anisotropic. With the increase of impact energy, the intensity ratios of L α /L β1 and L β2 /L β1 increase significantly. While the slopes of intensity ratios for L α /L β1 and L β2 /L β1 on emission angle do not change significantly at different impact energy. It indicates that the alignment degree A 20 is independent on incident energy from 20 to 40 keV. Consequently, the alignment degree A 20 for L 3 subshell is deduced to be 0.63 ± 0.10 experimentally.