Scanning Electron Microscopy Applications for Microtopography
The basic principle of a scanning electron microscope is not unlike that of the conventional transmission microscope. The electron optical column has the electron gun at the top and the electron beam is accelerated downward by a potential of 20kV. Three magnetic lenses reduce the size of the electron source in the gun from approximately 50μ to approximately 20Au at the specimen surface. This determines the resolution of the instrument.