Study of the angular and energy distributions of Na+ and K+ ions which have passed through thin copper films

Abstract

The angular and energy distributions of alkaline Na+ and K+ ions which have passed through thin Cu films in different crystal states are studied. The ion energy E0 is varied from 10 to 40 keV, and the incidence angle. ranges from 0° to 60°. The angular aperture of the detector is ∼0.5°, which allows the form of the angular distribution of ions which have passed through the solid thin films as a function of the energy, the angle of primary-ion beam incidence, and the layer thickness to be studied in detail. It is shown that, in the range E0 = 10.40 keV, the energy loss ΔE of those ions that have passed increases linearly as the energy of incident ions increases. The energy loss increases with increasing ion mass in the case of singly charged ions. The surface amorphization of single- and polycrystalline films leads to an increase (by 150–200 eV) in the energy loss caused by the diffuse propagation of ions and to loss-peak broadening. It is probable that surface amorphization is accompanied by an increase in the number of atoms experiencing multiple collisions with atoms of the film, which leads to an increase in the average energy loss by ions that have passed through films.