Approximate Theoretical Treatment of Weak‐Beam Dislocation Images

A simple approach is reported allowing to deduce the well‐known approximate criterion which relates the strain field of a dislocation to its image position in a weak beam. The proposed approximations also permit to make predictions about the width of the image peaks and the image contrast. The obtained results are compared with the intensity profiles calculated by performing the kinematical integral. It is shown that the mentioned position criterion, deduced within the one‐beam kinematical theory, can easily be adapted for a more realistic many‐beam theory, e.g. the two‐beam kinematical theory.