ENERGY-DEPENDENCE OF PARTICLE REFLECTION COEFFICIENT OF IONS FROM SOLID-SURFACES IN THE LOW-ENERGY REGION BELOW 200 EV

The reflection coefficients of Cu+ and Ni+ ions from graphite and gold film deposited on graphite in the energy range between 10 and 200 eV have been measured using the retention method. The reflection coefficient is determined from the difference between the charge number obtained by integration of the current of incident ion beam through the target and the retained number of incident ion species, not reflected from the target, obtained by means of the RBS technique. It is found that the reflection coefficients of both ions from graphite are less than 0.10 and that those from gold film are peaked at around 40-50 eV and their peak values are about 0.40. The experimental data are compared with the computer simulation data calculated by Eckstein et al. taking into account the chemical binding of neutral atoms of irradiated ion species at the surface.