Measurement of the detection quantum efficiency of microchannel plates for medium energy electrons

The detection quantum efficiency (DQE) of microchannel plates for electrons in the energy range from 5 to 50 keV was measured with enough spatial resolution to resolve the single channels using a scanning electron microscope. Between 10 and 50 keV the DQE is found to decrease with increasing energy from 0.4 to 0.2. Microchannel plates for image intensification in electron microscopy have been found inferior to photographic recording and well designed image pickup devises using phosphor screens on fibre plates. Nevertheless their DQE is sufficient for observing low intensity electron images at a high brightness level if some additional noise can be tolerated.