Large-angle Back-Scattering of Arq+ (q=1–13) During Quasi-Binary Collisions with CsI(100) in the Energy Range 10 Ev/q –2.8 Kev/q: Energy Loss Analysis and Scattered Charge State Distributions

We report on measurements of absolute scattered projectile charge fractions for Ar11+ ions with incident energies in the range 3–30 keV, that have been 120° back-scattered from CsI(100) in quasi-binary collisions. Use of a time-of-flight technique that incorporates a biased drift region permitted full separation of all scattered charged states, including neutrals. In contrast to our Ar11+ results for Au(110), the scattered neutral fraction is smaller, and relatively independent of incident projectile energy over the entire investigated range. In addition, we have measured, at a fixed energy of ∼5 keV, scattered charged state distributions as function of incident charge states in the range 1+ to 13+. In a separate measurement utilizing electrostatic instead of TOF analysis of the scattered charge states, we attempted to evaluate the effect of surface charging on energy loss of low energy scattered projectiles by absolute measurements of the scattered 1+ energies of incident Ar11+ ions incident on CsI(100) at energies down to 10 eV/q. Apart from small deviations from the elastic binary collision energy loss expected for large angle scattering, ascribable to the image charge interaction, no measurable effect due to surface charging was found down to the lowest investigated energies.