Dechannelling of Fast Charged Particle from Planar Channel Based on the Stochastic Theory

Abstract

The probabilities of scattering of planar channelling particles by electrons and thermal vibrations of atoms are derived. Using these probabilities, a Fokker-Planck equation to describe the behaviour of channelling particles in the transverse energy space is obtained. The decrease of the fraction of channelling particles with penetration depth, i.e., dechannelling, is calculated by solving the Fokker-Planck equation numerically. The results show good agreement with the experimental data of dechannelling of H⁺ ions in (110) channels of germanium and silicon. It is also demonstrated from numerical calculations that the ordinary diffusion equation can be approximated to the Fokker-Planck equation.