Quantitative reflection electron diffraction in an ultra high vacuum camera

Abstract

An ultra high vacuum electron diffraction camera for intermediate energies (10–50 kV) is described. A Faraday cup scans the diffraction pattern while another monitors the incident beam, reading out the intensities with high accuracy. The performance of the instrument is illustrated with typical diffraction patterns and scans. Reasons are discussed for expecting that the intensity data from high-energy electron diffraction is more satisfactory than from low-energy electron diffraction for the determination of surface structure, since dynamical theory must be used.