SECONDARY ELECTRON DETECTOR

摘要

PURPOSE:To determine the shape of an auxiliary electrode which determines the orbit of secondary electrons emitted from a specimen in regard to the structure of a secondary electron detector for a scanning electron microscope and the like. CONSTITUTION:The shape of an auxiliary electrode 8 is formed into a cylinder, the upper and lower sections of which are made asymmetric about its cylindrical axis. And the auxiliary electrode 8 is electrically insulated from an earthing electrode 3 by a spacer 2 while arbitrary positive voltage is being applied. By this constitution, even when a secondary electron detector is disposed in a place lower or than identical to a place for a specimen, secondary electrons emitted from the specimen can be efficiently converged into a scintillator without being caught by the auxiliary electrode.