Simulation of energy spectra of slow He ions scattered from a copper surface

Scattering of low energy (2 keV) He⁺ ions from a polycrystalline copper surface is studied. Experimental Time-Of-Flight (TOF) spectra are presented for different values of the angle of incidence α and a fixed scattering angle θ = 129°. Using Monte Carlo simulation, based on the TRIM (TRansport of Ions in Matter [6]) code, energy spectra are calculated and compared to experimental data. The influence of different combinations of interaction potential and inelastic energy loss on the spectrum shape and on the angular distribution of the scattering yield is considered in the simulation. Simulations show very good agreement with the experiment for all investigated geometries. An analysis of the experimental yield of scattered particles in different parts of the spectrum is performed to gain information on the relative contributions of surface single scattering and multiple scattering.