Potential and stopping-power information from planar-channeling oscillations

Abstract

A method is developed for analyzing measurements of the backscattering of ions from a crystal under planar-channeling conditions in which the intensity of scattered ions is observed as a function of emergent energy. Attention is concentrated on two features of such observations, the energy separation of the strong series of peaks seen when the ion beam is exactly parallel to the planes and the angle ${\ensuremath{\psi}}_{M}$ of inclination of the beam to the planes that produces the maximum yield of backscattered ions. Computer simulation of ion trajectories using various assumed ion-atom interaction potentials is used to show that ${\ensuremath{\psi}}_{M}$ is a measure of the strength of the potential. The simulation results are also used to show how the half wavelength of the oscillations can be calculated from ${\ensuremath{\psi}}_{M}$. From the half wavelength and the separation of the peaks in the measured energy spectrum of the backscattered ions, the average stopping power the ions experience in their oscillating trajectories can be calculated. Applications of the method to experiments are discussed.