Accurate Computer Simulation of Electron Microscope Images

Abstract

THE results of theoretical electron microscope image calculations are usually presented as profiles which give the variation of transmitted or diffracted intensity along a line in a plane normal to the electron beam¹. These data can be correlated directly with microdensitometer traces obtained from experimental micrographs; nevertheless this correspondence is normally established intuitively from an enlarged print of the micrograph. For this reason alone there would appear to be advantages in presenting calculated intensities as a simulated electron micrograph. Such a display, first achieved by Head² using a computer line printer, has now been developed on a Stromberg–Carlson 4060 microfilm recorder which is inherently more versatile and capable of much better definition. A qualitative description of the technique is given in this communication and to illustrate the result an image comparison is made between experiment and theory for the case of an edge dislocation loop in a molybdenum crystal.