A test of theoretical K-shell ionization cross sections for protons

Abstract

Various sophisticated theories (relativistic plane wave Born approximation (RPWBA), semi-classical approximation (SCA), coupled-channels codes) are tested by comparison to our recent extended list of empirical K-shell ionization cross sections for protons. Differences between the theories are outlined. Surprisingly, the elaborate coupled-channels codes appear low compared to experiment, especially for light targets. Possible reasons for this are discussed. The RPWBA calculations describe the data better in a large projectile velocity range, in spite of the fact that binding and Coulomb effects are only treated as corrections. The SCA calculations by Hansteen et al. appear closer to the data than those by Trautmann; this is surprising since both codes should give identical results. Systematic comparisons are still severely hampered by the fact that most published cross sections describe different targets or different energies.