Velocity effect in secondary electron emission below and above the electronic stopping power maximum

Abstract

We studied secondary electron emission yields γ from a carbon surface with helium projectiles near the electronic stopping power maximum (0.2–2 MeV). We ask the question: “Does γ depend on the electronic stopping power (dE/dx)e only or is there an additional dependence on the projectile velocity VP?” A velocity effect is indeed found for backward emission. The results are discussed in the framework of recent electron transport and track models and compared with the yield of secondary ions from the same collision system.