Kinematical and weak beam dark field WBDF images of dislocations

5 Kinematical and weak beam dark field (WBDF) images of dislocations 

1 Introduction. In Sections 5.3 and 5.4, we considered the contrast of planar defects and dislocations in terms of the two-beam dynamical theory (including absorption) when the crystal is set at or near the exact Bragg angle (i.e., when s is zero or small). These diffracting conditions (which are usually described as dynamical) are, in general, satisfactory for determining the nature of the planar defects from the details 

1 The dislocation image lies to one side of the dislocation, in agreement with the intuitive explanation of the origin of dislocation contrast given in Section 5.1. 

2 The displacement of the image peak from the position of the dislocation is of the same order as the width of the image. 

3 The image displacement and image width increase with n. 

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