Inner shell electron pick-up by protons and other light ions

The capture of inner-shell electrons by fast light ions is investigated. This process essentially contributes to the ionization cross section of inner shells. The method used is a modified version of the impulse approximation and of the higher order Born approximation adjusted to asymmetric processes. The method is described in detail. Applications for numerical calculations of differential cross sections of electron capture processes from Ne and Ar atoms by fast light projectiles (protons, He, Li ions) are also described. The angular dependence of cross sections is measured and calculated. The theoretical and experimental data are compared. Further possible applications of the developed methods are briefly reviewed. (D.Gy.)