Detectors for the scanning electron microscope

Abstract

Although the scintillator/photomultiplier combination is the detector most commonly used in the scanning electron microscope, it has been found advantageous for some purposes to derive the signal from the current passed by an insulated specimen to a operational amplifier with high-impedance input. An alternative to this latter arrangement is described where the specimen is biased a few tens of volts negatively with respect to earth and electrons leaving it are collected by the surrounding metal box.