Inner-shell effect on the sulphur projectile charge state after single close collisions with rare gases

Abstract
Sulphur K-shell vacancy production probabilities in single close collisions at high projectile energies with Kr and Xe have been determined by particle-photon coincidence techniques. Subtracting this K-shell excitation contribution from the average outgoing charge state of S measured under the same experimental conditions, the average degree of outer-shell ionisation has been determined. It is found to depend only weakly on the atomic number of the target and to be in general agreement with the predictions of the dynamic screening model using the multiple-collision equilibrium average charge state. Charge state distribution widths are the same as after collisions with solid targets, supporting the conclusion that a kind of equilibrium is established in these collisions.