The Critical Voltage Effect in High-Voltage Electron Microscopy

In addition to revealing the internal microstructures of materials, the high-voltage electron microscope can also be used to characterize "invisible " features such as electron scattering, site occupancy, and atomic displacement ampli-tudes on a quantitative basis. The physical basis of the unique "critical voltage effect " is the occurrence of de-structive interference between current waves within the specimen at a particular accelerating voltage. Potential applications to studies of random and ordered alloy solid solutions largely depend on the magnitude of the size dis-parity between solute and solvent atoms