Comparative study of target atomic number dependence of ion induced and electron induced secondary electron emission

Abstract

Target atomic number, Z 2, dependence of ion-induced electron emission is investigated by means of a Monte Carlo simulation for 17 species ( Z 2=4–79) of solids bombarded with light (He, Ne) and heavy (Kr, Xe) ions with the energy of 50 keV. The simulation derives the contributions of electron excitation by a projectile ion, recoiled target atoms and electron cascades from the total electron yield. With increasing Z 2 the electron yield decreases while showing a detailed structure. The Z 2 dependence is different from that for electron bombardment, where the secondary electron yield increases with increasing Z 2. The decreasing electron yield for heavy ions with increasing Z 2 is due to the decrease in the number and energy of electrons excited by the projectile ion, resulting from a large energy transfer from the projectile ion to the recoiled atoms. Furthermore, the decreasing component from the recoiled atoms contributes it as well.