Éditeur(s) : HAL CCSD IOP Publishing
Résumé : International audience
M-subshell ionization cross sections of U by electron impact with kinetic energies between 4 and 38 keV were determined experimentally. The cross sections have been deduced from high-resolution measurements of the M x-ray emission spectra resulting from the radiative decay of M-subshell vacancies. The experimental cross sections are compared with cross sections calculated within the plane- and distorted-wave Born approximations. The predictions of the distorted-wave Born approximation represent experimental measurements well within experimental errors.
ISSN: 0953-4075

hal-01054329
https://hal.archives-ouvertes.fr/hal-01054329
DOI : 10.1088/0953-4075/47/5/055202

Éditeur(s) : HAL CCSD American Physical Society
Résumé : International audience
Absolute M-shell x-ray production cross sections have been measured and calculated for Au and Bi for electron incident energies from close to the ionization threshold up to 38 keV. The experimental cross sections were deduced from M alpha x-ray intensities emitted from ultrathin Au and Bi samples deposited on self-supporting C films. The measurements were performed on an electron microprobe using several wavelength-dispersive spectrometers. The x-ray production cross sections were also evaluated theoretically using ionization cross sections calculated from the plane-wave and the distorted-wave Born approximations. Experimental results are compared with the calculated cross sections and also with the results of two analytical formulas widely used in many applications. Good agreement is found between the measured cross sections and the predictions from the distorted-wave Born approximation, which indicates that this approximation is suited for the calculation of M-shell ionization cross sections of heavy elements.
ISSN: 1050-2947

hal-00411432
https://hal.archives-ouvertes.fr/hal-00411432
DOI : 10.1103/PhysRevA.78.022704

Éditeur(s) : HAL CCSD Wiley-Blackwell
Résumé : International audience
Absolute Mα x-ray production cross sections have been measured and calculated for heavy elements Au, Pb, Bi, and U for electron incident energies from the ionization threshold up to 38 keV. The experimental cross sections were deduced from M x-ray intensities emitted from ultrathin samples of the elements of interest deposited onto self-supporting C films. The measurements were performed using two electron microprobes and several wavelength-dispersive spectrometers. X-ray intensities were converted into x-ray production cross sections by using estimated values of the number of incident electrons, target thickness, and spectrometer efficiency. Experimental results are compared with calculated cross sections using different predictive formulae. Good agreement is found between the measured cross sections and the predictions from the distorted-wave Born approximation, which indicates that this approximation is suited for the calculation of M-shell ionization cross sections of heavy elements.
ISSN: 0142-2421

hal-01122839
https://hal.archives-ouvertes.fr/hal-01122839
DOI : 10.1002/sia.5561