Electron microbeam systems for solid material investigation

The capabilities are discussed of focused electron beams of imaging the solid material strUcture, this down to a level of the individual atoms. The focused electron beam diameter is affected by the aperture aberration of the electron lens and by the electron beam wavelength. The desired beam parameters are also affected by the properties of the electron source. In this respect, self-emission from tip cathodes appears to be more favourable. Methods are briefly described allowing to increase image contrast, based on observing scattered electrons and the consequences are discussed of radiation damage of objects. Elastic scattering is inevitable for obtaining information on the object under study while inelastic scattering can in a limited extent be used for obtaining other information. Methods using high detection efficiency should be selected in order that the radiation damage of the object be minimized. (Z.M.)