Recent Results on K-Shell Ionization by Ion Collisions
The experimental K-shell ionization cross sections of 48Cd, 50Sn, 52Te, 53I and 56Ba for alpha particles, between 2.2 MeV and 2.8 MeV, and of 52Te for protons, between 1.6 and 3 MeV, are presented. The justification for making these measurements comes, on the one hand, in filling a region where, at present, data are sparse: for example, 52Te ionization cross sections by alpha particles have never been reported before, and, on the other hand, checking between previously reported and diverging sets of experimental results: for example, for alpha particles on tin. In addition, the K-shell ionization cross sections of 52Te for protons can be considered as an extension of Khelill's measurements.
K-shell ionisation by protons, deuterons and alpha particles at low projectile energies
The semiclassical approximation model (SCA) with hyperbolic projectile trajectories, including target recoil and symmetrisation, is used to study Coulomb ionisation in the incident energy range from 50 to 300 keV for a Ni target. Combined with corrections for the binding effect and the relativistic behaviour of the target electrons, the first-order SCA theory yields total cross sections consistent with recent measurements. No variation of parameters is performed.
Electronic relativistic effects on K -shell ionization by low-energy protons
$K$-shell ionization cross sections by low-energy proton impact have been calculated in the relativistic plane-wave Born approximation, taking into account the effects of binding-energy increase and Coulomb deflection. The calculated values are compared with the recent experimental cross sections of Zander and Andrews. It is found that the use of Dirac wave functions for target electrons improves agreement with the experimental results, but the theoretical predictions are still systematically higher at the lower proton energies.