Charge Exchange and Energy Loss of Particles Interacting With Surfaces

Abstract

Experiments on energy dissipation of He-particles interacting with metal surfaces have been performed. The energy range used was 1 – 5 keV. The particles were scattered off a Ni(110) surface at grazing incident angle (5°) and detected under specular reflection condition with a time-of-flight system.

The resulting spectra of backscattered neutral particles show an energy loss of about 5% of the incident energy and an asymmetric shape. These features can be accounted for by two models: 1.- The friction coefficient method describes the interaction via friction coefficients depending on the charge state of the particle. 2.- The convolution method is based on the assumption that each impinging particle excites a number of elementary excitations in the target.

In both cases energy straggling plays an important role.