Electron optical benches for in-line and branched systems. A new bench designed for mirror-based aberration correction and low energy electron microscopy

Abstract

A review of electron optical bench literature is presented, and the designs of two optical benches used by the authors are described. One bench was designed for testing individual electrostatic electron lenses and in-line optical systems, for example, emission electron microscopes and transmission electron microscopes. It has been in operation for many years. The second electron optical bench is new. It is a branched system designed for several purposes: to study correction of spherical and chromatic aberration with an electron mirror, and to gain experience with low energy electron microscopy (LEEM) optics. The alignment of the electron optical support structure is independent of the vacuum housing, and the bench is designed to be operated either horizontally or vertically. As a demonstration of the performance of the new bench in the horizontal mode, a test pattern on a silicon surface was imaged with LEEM optics.