Origin of Convoy Electrons Produced by Swift Neutral Hydrogen and Proton Beams Traversing Carbon Foils

An experiment is presented demonstrating that for both swift neutral hydrogen and proton bombardments (0.9-2.0 MeV/u) on carbon foils, the origin of cusp-shaped convoy electrons is mainly attributable to a final-state interaction between projectiles and free secondary electrons traveling with velocities around the projectile velocities near the exit surface of the target foils. The direct contribution to the cusp-shaped convoy electrons of target-electron transfer to the projectile continuum is found to be relatively unimportant.