Beam profile of a parallel plane electrodes focusing system

Abstract

The present work investigates the potential distribution in a five electrode lens to be used in an electrostatic ion source. The beam profile shape has been investigated using different gases. The radii of the beam profile along the axial distance using N/sub 2/ gas are calculated for different perveances, different initial beam radii, different ion charges, and different ratios of voltage magnitude. It has been found that a minimum beam radius of 0.22 mm can be obtained for initial beam radius equal 2.5 mm using N/sub 2/ gas. The present lens constitutes a convergent lens. It gives a more focused beam than the case of two hemispherical electrodes and an intermediate flat electrode.