Computer Simulation of Ion Beams for the Design of Three-Electrode Ion Extraction System

Abstract

The divergence of ion beams extracted from a three-electrode extraction system (positive, negative, and grounded electrode) with circular apertures is calculated numerically by using a digital computer. The beam divergence depends on the shapes and sizes of the apertures, the spacings between them and other parameters such as the electrodes' potentials, the current density emitted from the source plasma surface and the curvature of the plasma surface which is fixed. A circular aperture electrode gives a smaller beam divergence in comparison with a slit electrode. The results of the computation are available for experiments to study an optimum extraction system.