X-ray topography of diamond using forbidden reflections: which defects do we really see?

Natural and synthetic diamonds with various concentrations and types of point and extended defect were investigated using X-ray topography employing allowed (111, 004) and forbidden (222) reflections. On the topographs of the forbidden reflections, weak stress fields from lattice imperfections and extended defects are readily observed. Comparison of the topographs with IR maps of the distribution of point defects suggests that certain types of point defect may increase the structure factors of the forbidden reflections.