Defect analysis in crystals using X-ray topography

A brief review of X-ray topography--a nondestructive method for direct observation and characterization of defects in single crystals--is presented here. The origin and development of this characterization method and the different techniques derived from it are described. Emphasis is placed on synchrotron X-ray topography and its application in studying various crystal imperfections. Mechanisms of contrast formation on X-ray topographs are discussed, with emphasis on contrast associated with dislocations. Determination of Burgers vectors and line directions of dislocations from analysis of X-ray topographs is explained. Contrast from inclusions is illustrated, and their differentiation from dislocations is demonstrated with the aid of simulated topographs. Contrast arising from the deformation fields associated with cracks is also briefly covered.