Simulation and Optimization of the Optical Properties of an Einzel lens

Abstract

Abstract The simulation and optimization calculations were carried out for an einzel lens consists of three overlap cylindrical electrodes with the same length but with different electrode diameters under point-to-point focusing condition. The effects of the overlap distance (d) between the central and the outer cylindrical electrodes on the optical properties of an einzel lens were investigated. The results showed that the increasing of the overlap distance (d) will improve the aberration figures of the images, where by increasing the overlap distance (d) from 2 mm to 6 mm the dimensions of the image were reduced by about 50% for both y and z-directions. The results appeared that both the dimensions of the lens, and the aberrations can be reduced at the same time without affecting the homogeneous distribution of an electron-beam kinetic energy of at the image plane.