Zum Kontrast an Versetzungen im Röntgenbild

Abstract

The causes of contrast at dislocations on X-ray topographs taken with different techniques are discussed. It is shown that a variety of mechanisms may be important for the image formation and the type of contrast observed.

Particular attention is paid to the role which the deflection of wavefield rays in the long reaching strainfield of a dislocation may play in the formation of the dislocation image. For the case of dislocations imaged by the double crystal method paths of wavefield rays have been calculated numerically. Since in this case Braggcase wavefields are involved, the general theory of wavefield propagation in a weakly deformed lattice²⁴ had to be used. The results confirm the assumption that deflection of wavefield rays can contribute considerably to dislocation images obtained in X-ray topography.