Comparison of the target-thickness dependence of the convoy electron yield and the Rydberg electron yield measured in coincidence with exit charge states in fast ion-solid collisions

Abstract

We have simultaneously measured the yield of convoy electrons and the yield of electrons in high Rydberg states of the projectile ( n ≳ 70), produced by 2 MeV/u C projectiles passing through C foils, whose thicknesses range from 4–10 μg/cm 2, for incident charge states q i = 4–6 and exit charge states q e = 4–6. We have found that these yields exhibit similar trends as a function of foil thickness, but that, nevertheless, the ratio of the number of convoy electrons detected in coincidence with ions of exit charge state q to the number of electrons detected in high Rydberg states of ions with the same exit charge state is a function of foil thickness. This may be due to a broadening of the convoy electron energy spectrum with increasing foil thickness.