Secondary-ions from atomic collision processes in solid surfaces

Using time-of-flight technique (TOF) we investigated the secondary ion emission from an uncleaned carbon surface induced by fast helium bombardment near the maximum of electronic stopping power (dE/dx)(e). We examined the production of secondary ions dependend on projectile properties only, as specific projectile energy (50 keV/u less than or equal to E-p/m(p) less than or equal to 500 keV/u) and incident charge state (0 less than or equal to q(i) less than or equal to 2), but not on target properties, as surface conditions. The ''pre-equilibrium stopping power'' plays a major role in secondary ion production in the examinated projectile velocity regime.