Charge exchange of He+-ions with aluminium surfaces

Charge exchange of 4He+ and 3He+ ions with surfaces of polycrystalline aluminium and Al(1 1 1) was investigated in the low-energy ion scattering (LEIS) regime. Ion spectra were recorded for primary energies ranging from 280 to 4000 eV by using an electrostatic analyzer (ESA). A very low threshold energy Eth for collision induced charge exchange (CI) was deduced from the shape of experimental spectra. Ion fractions P+ were evaluated. No systematic difference in P+ was observed for both, the two surfaces investigated and the two different projectiles.