Shower approach in the simulation of ion scattering from solids

TL;DR

The paper introduces an efficient 'shower' simulation method for ion scattering from solids, enabling detailed analysis of scattering effects and validation of approximate models with significantly reduced computational cost.

Contribution

A novel shower approach for ion scattering simulation that reduces computational effort and allows comprehensive analysis of scattering phenomena and model validation.

Findings

Validated the accuracy of approximate ion-beam analysis methods.

Analyzed the role of double collisions and surface peaks in scattering.

Demonstrated the method's application to MeV ion channeling simulations.

Abstract

An efficient approach for the simulation of ion scattering from solids is proposed. For every encountered atom, we take multiple samples of its thermal displacements among those which result in scattering with high probability to finally reach the detector. As a result, the detector is illuminated by intensive "showers", where each event of detection must be weighted according to the actual probability of the atom displacement. The computational cost of such simulation is orders of magnitude lower than in the direct approach and a comprehensive analysis of multiple and plural scattering effects becomes possible. We use the new method for two purposes. First, the accuracy of the approximate approaches, developed mainly for ion-beam structural analysis, is verified. Second, the possibility to reproduce a wide class of experimental conditions is used to analyze some basic features of ion-solid collisions: the role of double violent collisions in low-energy ion scattering; the origin of the "surface peak" in scattering from amorphous samples; the low-energy tail in the energy spectra of scattered medium-energy ions due to plural scattering; the degradation of blocking patterns in 2D angular distributions with increasing depth of scattering. As an example of simulation for ions of MeV energies, we verify the time-reversibility for channeling/blocking of 1 MeV protons in a W crystal. The possibilities of analysis that our approach offers may be very useful for various applications in particular for structural analysis with atomic resolution.