Detector assembly for a scanning electron microscope

摘要

Electron detector configuration for an environmental scanning electron microscope (ESEM), for detecting electrons emanating from the surface of the specimen. The detecting means comprise a printed circuit board (132) including a detector head (134) having thereon an electrically biased ring detector electrode (136), the ring electrode being disposed between the specimen (24) and a pressure limiting aperture (144) that is positioned at the interface of the vacuum column (10) and the specimen chamber (22). The pressure limiting aperture is preferably provided with means for electrically biassing it such that it can act as an electrically biased pressure limiting aperture detector, and it is preferably formed integrally on the printed circuit board (132). <IMAGE>