Energy Reflection Coefficients for 5-10 keV He Ions Incident on Au, Ag, and Cu

The calorimetric deuterium-film method was used for measurements of the energy reflection coefficient γ for normal incidence of 5-10 keV He ions on Cu, Ag and Au. A theoretical calculation of γ by means of transport theory gives fair agreement with the experimental results. The experimental data for all three materials lie on a single curve, if depicted as a function of the reduced energy ε. γ varies from 0.14 to 0.04 with ε varying from 0.2 to 1.6. The calculated data do not show similar behaviour, and the position of each curve depends on the specific beam-target combination. Both the experimental and theoretical results for the He ions are in acceptable agreement with other experimental and theoretical results. For He ions, the experimental γ-values are 20-30% above the values for hydrogen ions for the same value of ε