Effective Charge Effect in 2·0–7·0 MeV Partially Stripped F^q+ – Helium Collisions

Abstract

The ratio of the double ionisation cross section to that of the single ionisation of helium was measured for 2·0–7·0 MeV F^q+ (q = 1,2,3,4) bombardment. The effective charge effect in partially stripped F^q+ – helium collisions is studied. It is found that the effective charge qeff increases as the impinging energy increases and that qeff shows almost no dependence upon the projectile charge state in the present energy range.