The formation of plane-wave X-ray images of microdefects

A theory of the formation of X-ray images of microdefects is developed. It is shown that at sufficiently high collimation of the incident wave it is possible not only to reveal such defects but also to obtain the images of their elastic fields almost without any additional diffraction within the Borrmann fan typical of the conventional topography. The possibility to observe displacement fields near microdefects with dimensions beyond the limits of X-ray topography resolution is demonstrated with the aid of computer simulation of wave fields and the analytical estimates. It is shown that plane-wave images give information on the type, dimensions, and orientation of microdefects. The effect of the incident-wave divergence on the experimental results is also discussed.