On the kinematical theory of diffraction contrast of electron transmission microscope images of perfect dislocations of mixed type

Tho kinematical theory developed by Hirsch et al. (1960) for the diffraction
contrast of electron microscope images of perfect screw dislocations parallel
to tho surface of tho crystal foil is extended to an arbitrary perfect dislocation
with slip plane parallel to the surface.
The line profiles are numerically calculated and tho variation of the line width, the position of the maximum and the valuo of this maximum with character of the dislocation line are discussed. It is argued that eventual dynamical correct ions, supposing the kinematical case to be valid for the perfect material, would not alter the qualitative predictions. If the dislocation bisects tho acute (obtuse) angle formed by the Burgers vector and the diffraction vector, its image has tho smallest (largest) possible width.
To all other orientations correspond profiles with intermediate values for the
widths. To a broader profile corresponds also a position of the image more
displaced away from the real position of the line.
It is also found that for n = g . b = 0, a broad, double contrast may arise for orientations near to the 1/4π orientation if the order of the reflection considered is high.