Scattering of light molecules from thin Al2O3 films

Molecular oxygen and hydrogen ions were scattered at grazing incidence from various thin Al2O3 films. The energy of incident particles was varied from 390 to 1000 eV. For scattered positive oxygen ions, negative ion fractions of up to 17% were recorded. For scattered positive hydrogen ions, the negative ion fractions reached up to 2%. These findings qualify thin films of Al2O3 as possible candidates for use as charge state conversion surfaces in neutral particle sensing instruments, which will work in space.