Detectors for electrons

Abstract

Detectors for electrons can be divided into two categories. In the first category, all electron beams are static in the sense that neither the beams incident on nor emergent from the specimen are varied in position or orientation during the detection and recording process. Detectors in the second category employ a scanning system to vary the position or orientation of the electron beams before or after the specimen. Whilst many of the properties required of total flux and flux-density detectors differ significantly, all detectors must satisfy certain criteria. A means of characterizing detectors is given together with a brief description of which particular features are desirable in each of the two categories. Specific detectors suitable for parallel recording are considered next, where a description is given both of their operation and of the extent to which they fulfil the criteria outlined in the preceding section. Finally, similar details are given for detectors suitable for serial recording purposes. This chapter is also available as HTML from the International Tables Online site hosted by the IUCr.