Introduction to Electron Optics for the Study of Energy Analyzing Systems (10)

Abstract

  In electron spectrometers, retardation of electrons by an input lens system is a standard technique for improving energy resolution. The effect of the retardation is explained with reference to the law of brightness, which shows how the sensitivity is changed according to the retardation. However, the concept of brightness loses its meaning if a source is assumed to be a point. In suh a situation, the sensitivity is governed by the amount of spherical aberration of a lens system. The dependence of resolution and sensitivity on retardation and the effect of the size of a source are discussed in detail in this chapter.