 The beam electrons interact with the specimen surface layer and produce various signals (information) that are collected with appropriate detectors.The output of these detectors modulates, via appropriate electronics, the screen of a monitor to form an image that corresponds to the small raster and information, pixel by pixel, emanating from the specimen surface.Beyond these common principles, the ESEM deviates substantially from an SEM in several respects, all of which are important in the correct design and operation of the instrument.