Systematics of the averageL-shell ionization probability inK-shell ionizing collisions by light ions

The apparent average $L$-shell ionization probabilities in $K$-shell ionizing collisions by He, C, O, and Ne ions incident on Al, Si, and Cl targets at relative velocities ranging from 2 to 8.5 have been determined from high-resolution $K\alpha$ x-ray measurements. These data, in combination with data from previous work, enabled a detailed examination of the dependence of the single $K$- plus multiple $L$-shell ionization process on projectile and target atomic number, and on relative velocity. The He-ion-on-Al data are compared with the results of binary-encounter approximation and semiclassical approximation calculations, and a general semiempirical scaling law is deduced for light-ion collisions.