Patent Number: 
Section: abstract

With a detector system for the specimen chamber of a scanning electron microscope, signals are simultaneously detected in transmission which signals correspond to a light field contrast and a dark field contrast. The detector system (14) includes four detectors (15 to 18) in a plane (25) between which an aperture (19) for free access of electrons is located. Behind the aperture (19), a further detector (27) is arranged in a second plane (26). The detectors are preferably diodes. The detectors (15, 16, 17, 18) in the first plane (25), which is closer to the specimen, serve to generate signals which correspond to a dark field contrast. The further detector (27), more distant from the specimen, detects signals corresponding to a light field contrast. Large dead spaces, which are not sensitive to electrons, between the diodes and around the aperture (19), can be avoided by the offset arrangement of four diodes (15, 16, 17, 18) in the first plane (25).