Potential and kinetic electron emissions from HOPG surface irradiated by highly charged xenon and neon ions

Highly charged Xe-129(q+) (q - 10-30) and Ne-40(q+) (q - 4-8) ion-induced secondary electron emissions on the surface of highly oriented pyrolytic graphite (HOPG) are reported. The total secondary electron yield is measured as a function of the potential energy of incident ions. The experimental data are used to separate contributions of kinetic and potential electron yields. Our results show that about 4.5% and 13.2% of ion's potential energies are consumed in potential electron emission due to different Xeq+-HOPG and Neq+-HOPG combinations. A simple formula is introduced to estimate the fraction of ion's potential energy for potential electron emission.