M shell ionization of Ar induced in near-central collisions with MeV protons

Abstract

High energy resolution x-ray emission spectra of Ar induced in collisions with 0.75–3.0 MeV protons were measured using a complete in-vacuum curved-crystal x-ray emission spectrometer in Johansson geometry. The satellite lines were clearly resolved in the measured spectra and their intensity relative to the parent diagram line was used to extract the M shell single ionization probability for near-central collisions. The experimental values are compared to the theoretical predictions calculated within the semiclassical approximation (SCA) and also the binary encounter based geometrical model. Very good agreement with experimental data was achieved for the SCA values employing concise Dirac–Hartree–Fock wave functions for the description of valence M shell electrons.

Multielectron ionization contributions in valence‐to‐core x‐ray emission spectra of third‐row elements

“…The intensity of the K β M satellite lines relative to the parent diagram line should therefore exhibit dropping dependence with increasing proton energy, 29 which is confirmed clearly by our measurements presented in Figure 6 (left). To provide more quantitative comparison the model spectrum composed of a single Voigt profile for the K β 1,3 diagram line and two Gaussian profiles describing the K β M 1,2 satellites was fitted to the measured spectra (Figure 6) in the same way as it was done for the measured Ar spectra 29 . The extracted relative intensities of the satellite lines are plotted as a function of proton energy and compared to the corresponding Ar values in Figure 6 (right).…”

“…In this case the multiple ionization is governed by direct Coulomb's interaction between charged particles and the corresponding ionization cross section depend on the projectile velocity. 32 The intensity of the KβM satellite lines relative to the parent diagram line should therefore exhibit dropping dependence with increasing proton energy, 29 which is confirmed clearly by our measurements presented in Figure 6 (left). To provide more quantitative comparison the model spectrum composed of a single Voigt profile for the Kβ 1,3 diagram line and two Gaussian profiles describing the KβM 1,2 satellites was fitted to the measured spectra (Figure 6) in the same way as it was done for the measured Ar spectra.…”

“…First, we can take a look at Ar, which is the closest atomic neighbor. In the past we have already used our spectrometer to collect Ar K β XES spectra induced with monochromatic synchrotron radiation and also MeV protons 6,29 . Figure 5 shows the comparison of three spectra measured with the same spectrometer but using different excitation.…”

“…In the past we have already used our spectrometer to collect Ar Kβ XES spectra induced with monochromatic synchrotron radiation and also MeV protons. 6,29 Figure 5 shows the comparison of three spectra measured with the same spectrometer but using different excitation. The first two spectra were recorded at ID26 beamline of ESRF synchrotron using monochromatic synchrotron radiation and the excitation energy was tuned slightly below (3220 eV) and above (3230 eV) 1s3p double excitation threshold.…”

A study of KαL1 X‐ray satellite spectrum of the elements 27 ≤ Z ≤ 31 by photon excitation

“…Thus, the excitation mechanism being materially different, the relative intensity of the Xray satellites produced by photon and ion excitation cannot be expected to be equal, although the energy shifts of these satellites from the diagram linear found to be very nearly equal . [6] Just to cite an example, KL 1 satellite relative intensity of Ca was measured in our laboratory, [7] which was found to be nearly three and half times lower than that reported by McWherter et al [8] who generated the satellites by proton excitation. In fact, the relative intensity of the X-ray satellites is found to vary with the charge and energy of the ions.…”