Collimator and telescopic modes of a cathode lens

Abstract

One way to improve the performance of emission systems (electron microscopes, microfocus X-ray tubes, etc.) is to reduce cathode lens aberrations. Such a reduction is only possible through a thorough theoretical analysis of their electron-optical schemes. This research attempts to develop tools for modeling a cathode lens with a virtually arbitrary electrode configuration in the paraxial approximation, and the conditions for implementing the collimator and telescopic modes have been determined. The relationship between the parameters that provide the specified operating modes of the lens has been studied. Electron-optical schemes have been developed that guarantee collimator and telescopic modes of a cathode lens of a real (non-idealized) design.