Projection-type electron spectroscopy collimator analyzer for charged particles and x-ray detections.

Abstract

We developed a compact sized device for angular and energy analysis of charged particles in a wide acceptance cone angle of nearly 1π steradian. This device is configured from an electrostatic lens comprising an axisymmetric aspherical mesh, which has a concave shape viewed from the point source, a set of axisymmetric electrodes, planar grids, microchannel plates, and a fluorescent screen positioned coaxially. The potentials of electrodes are adjusted so that the trajectories of the electrons with arbitrarily set kinetic energy are substantially parallelized by the electrostatic lens and enter the planar grid perpendicularly. Instead of the planar grid, a collimator plate with parallel holes can be used as an energy band-pass filter. The angular distribution of electrons with the selected kinetic energy is projected directly onto the fluorescent screen without converging and passing through a pinhole. This is a simple but significant electron-optical design to obtain wide-range angular distribution with high angular resolution, and the analyzer can be suitably used for the two-dimensional angular distribution measurements of electrons and ions emitted from surfaces.