PROJECTILE DEPENDENCE OF ION-INDUCED ELECTRON-EMISSION FROM THIN CARBON FOILS

The total secondary-electron yield from thin carbon foils traversed by heavy ions has been measured as a function of the projectile atomic n umber Z(p), the initial charge state, and the incident velocity. For n early all projectiles in the velocity region studied the number of emi tted electrons per incoming projectile gamma and the stopping power S have, as expected, the same velocity dependence. However, for ions wit h Z(p) > 29 a slight increase of the ratio LAMBDA = gamma/S with the p rojectile energy is observed. A systematic study of the ratio LAMBDA a s a function of the projectile atomic number Z(p) indicates a Z(p)-0.2 dependence of the parameter LAMBDA. Possible explanations for this Z( p)-0.2 dependence of the LAMBDA parameter are given.