A computer program for many-beam image simulation of amplitude-contrast images

A computer program for the simulation of amplitude-contrast electron micrographs is described. The program is based on the n-beam dynamical theory of diffraction contrast as described by Howie and Whelan (see Howie, A., and Whelan, M.J. (1961) Proc. R. Soc. Lond. [Biol]). The displacement fields associated with crystal lattice defects are calculated using linear anisotropic elasticity. The program can be used to simulate images of crystals containing line or planar defects or combinations of these defects. The line defects can be oriented freely within the foil, and are not restricted to being mutually parallel, but must be straight. Different techniques available for solving the diffraction problem, with or without the column approximation, are discussed.