Helium-induced L-shell ionization cross sections

Abstract

The helium-induced L-subshell ionization cross sections have been calculated and compared graphically with recent experimental results. The calculations have been made by the relativistic plane-wave Born-approximation theory, using the Dirac wave functions for the target electron. The corrections for the increased binding energy and Coulomb-deflection effects have been taken into account. The experimental values for various target elements are normalized to the corresponding theoretical values and plotted against an effective reduced velocity parameter. This universal plot shows satisfactory agreement between theory and experiment for L 1 and L 3-shell ionization cross sections. However, for the L 2 shell the calculated values are systematically smaller than the experimental data. Possible reasons for the discrepancy are discussed.