No abstract

This paper reports on the investigation of the double K-shell ionization of metallic aluminum induced by photon and electron impact. The experimental method consisted to measure the K␣ hypersatellite spectra resulting from the radiative decay of double 1s vacancy states by means of high-resolution x-ray spectroscopy using a Bragg-type von Hamos crystal spectrometer. Measurements of the photon-induced spectra were carried out at the European Synchrotron Radiation Facility, Grenoble, France, while those of the electron-induced spectra were performed at the University of Fribourg. The double 1s ionization probabilities and cross sections were derived from the K␣ 2 hypersatellite to diagram line intensity ratios for photon beam energies ranging between 3.1 and 5.5 keV and for different incident electron-beam energies ranging between 4 and 20 keV. The energy and linewidth of the K␣ 2 hypersatellite x-ray line were also determined for which consistent results were obtained from the photon and electron-beam measurements.

No abstract

Abstract. High-resolution measurements of the photoinduced X-ray emission of liquid mercury were performed, using a transmission DuMond-type crystal spectrometer for transitions above 11 keV and a reflection von Hamos-type crystal spectrometer for transitions below 11 keV. The target X-ray fluorescence was produced by irradiating the sample with the Bremsstrahlung from X-ray tubes. The energies and natural linewidths of 6 K-shell, 26 L-shell and 2 M -shell X-ray transitions were determined. Using a least-squaresfit method to solve the two sets of equations derived from the observed transition energies and transition widths the binding energies of the subshells K to M5 and O1 and the level widths of the subshells K to N5 and O1 could also be determined.

Abstract. The multiple ionization of the L-and M -shells of Pd by fast oxygen ions has been studied by measuring with high-resolution the satellite structures of the Lα1,2 X-ray transitions. Relativistic multiconfiguration Dirac-Fock (MCDF) calculations were used to interpret the complex X-ray spectrum, allowing to derive the number of L-and M -shell spectator vacancies at the moment of the X-ray emission. After correcting these numbers for the atomic vacancy rearrangement processes that take place prior to the X-ray emission, the ionization probabilities corresponding to the collision time were obtained. The latter were compared to predictions of the semiclassical approximation (SCA) and the geometrical model. The SCA calculations were performed using relativistic hydrogenic and self-consistent Dirac-Hartree-Fock (DHF) electronic wave functions. It was found that the use of the more realistic DHF wave functions in the SCA calculations leads to a much better description of the measured ionization probabilities for both the Land M -shells.

The x-ray satellite structure of Pd Lα 1,2 (L 3 M 4,5 ) transition excited by an impact of O 7+ and Ne 6+ ions with energies 279 and 178 MeV, respectively, which were measured using a high-resolution von Hamos crystal spectrometer, is discussed in terms of the multi-configuration Dirac-Fock (MCDF) calculations. We demonstrate, by using the arguments of the general central limit theorem (GCLT), that a structure of complex M-shell satellites of Pd Lα 1,2 (M −m ) transitions for a higher number of spectator vacancies (m > 4), which consists of hundreds of thousands of individual x-ray transitions as obtained from the MCDF calculations, can be well described by a single Voigtian profile. The Lorentzian width of such Voigtian line can be well modeled by using the results of the MCDF calculations for simpler configurations with a number of vacancies m ≤ 4 . This method allows one to describe realistically a complex structure of M-shell satellites, thus extending the applicability of the MCDF calculations, which are limited by an increasing complexity of numerical calculations.