Saturation effects in projectile electron loss

The behavior of the projectile electron-loss cross sections with the target atomic number, Z₂, presents a saturation as the value of Z₂ increases. This fact, which had elready been observed for the excitation of highly charged projectiles, appears in the first-order calculations for the contribution of the projectile electron-target electron interaction but not for the projectile electron-target nucleus interaction. In this work, we compare total electron-loss cross sections with Electron Loss to the Continuum (ELC) yields, for 1.0 MeV He ^- projectile on various targets, with atomic numbers ranging from 2 to 54. Besides a similar saturation with Z₂ observed in both cases, some differences between the data appear, such as enhanced values of the total loss for all targets when compared to the ELC and a structure between the Ar and Xe targets also in the total loss data. These differences may be assigned to the contribution due to the interaction between the projectile active electron and the target electron cloud.