L-Shell Ionization of Gold by Heavy-Ion Impact

Abstract

There are several studies for L-shell ionization by light ions (e.g. recently Brandt and Lapicki 1979, Justiniano et al. 1980). However, the number of investigations is less for heavier projectiles (Z1 ≥ 3), and first of all the x-ray production cross-sections or the ratios of the cross-sections for the individual L-subshells were determined in these works in the high energy region. Thus, e.g. Li et al. (1976) showed that the ratios of the L-subshell ionization cross-sections for heavy targets bombarded by different ions cannot be interpreted by the direct ionization theories (PWBA, SCA, BEA), especially for relatively low collision velocities. Recently Sarkadi and Mukoyama (1980) investigated the validity of the hypothesis of the direct mechanism for L-shell ionization by heavy ions. They determined the L-subshell ionization cross-sections of Au bombarded by C+, N+ and O+ ions in the energy range 0.2–0.3 MeV/amu on the basis of their measurements of the production cross-sections of several L x-ray groups and transitions. Also a detailed comparison of the data for cross-sections was given by these authors with the predictions of the plane-wave Born approximation corrected for the increase of the binding energy, the Coulomb deflection and the relativistic effects (PWBA-BCR).