The Paths of Plurally Scattered Ions in Heavy Ion Elastic Recoil Detection Analysis

HIERDA spectra are complicated by the pronounced broadening and tailing effects that arise from the frequent plural and multiple scattering undergone by swift heavy ions in solids. The quantitative evaluation of these spectra is dependent on a clear understanding of the contribution of plurally scattered ions. A TRIM based Monte Carlo ion transport code has been shown to reproduce all features of HIERDA spectra and is used here to study the ion paths. The large number of scattering events that each ion undertakes makes the handling of the full scattering histories unwieldy, but the second and subsequent largest scattering angles from individual ion paths may be used to characterise plural scattering. The paths of scattered incident ions and recoiled target atoms have been modelled for 60 MeV I ions incident on Au, as well as other projectile-target combinations. The plural and multiple scattering contributions to HIERDA spectra are quantified and frequency distributions of large deflection scattering events are presented. Simulation results are compared with experimental measurements conducted on the ToF-E HIERDA facility at Lucas Heights.