Spectres auger et sections efficaces d'ionisation de la couche L 23 du magnésium et de l'aluminium sous impact de protons et d'ions lourds (10–100 keV)

Abstract

A comparison of Auger structures observed on the energy distributions of secondary electrons emitted from Mg and A1 solid targets bombarded by either light particles (H + and He +) or heavy ions (Ne +, Ar +, …) is presented. With incident protons, it essentially appears a broad peak corresponding to a L 23VV transition and a weak shoulder due to the surface and bulk plasmon excitation. The Auger structures obtained with heavy ions are richer and the peaks which compose it are sharper. Such atomic-like structures correspond to Auger transitions from excited (with one or two L 23 holes) moving recoiling atoms. The experimental L 23 Mg and A1 ionization cross sections were determined from Auger spectra. In H +−Mg (or A1) collisions our results are in good agreement with the theoretical values calculated in a PWBA model. In the case of heavy ion-target interactions, we compared the experimental measurements with ionization cross section calculations obtained in a Landau-Zener model.