Selective production of Li-, Be-, and B-likeKvacancy states in fast Ne projectiles studied by zero-degree Auger spectroscopy

High-resolution measurements of Ne K Auger electrons have been performed using multiply charged ²⁰Ne projectiles in collisions with He, CH₄, and Ar at impact energies of 70 and 100 MeV. Kinematic line-broadening effects were substantially reduced by observing the electrons at 0^∘{} with respect to the beam axis. For the He-gas target the outer-shell electronic configuration of the incident ions is essentially retained during K-shell ionization. Thus, B-, Be-, and Li-like electron configurations were selectively produced for incident ions of Ne⁴⁺, Ne⁵⁺, and Ne⁶⁺, respectively. For target gases CH₄ and Ar, Li-like lines are found to be strongly excited, independent of the initial charge state of the projectiles.