Reticulography: a simple and sensitive technique for mapping misorientations in single crystals

Interposition of a fine-scale X-ray absorbing mesh between a Laue-diffracting crystal specimen and the photographic plate recording its topographic image splits the diffracted beam into an array of individually identifiable microbeam elements. Direction differences between the microbeams in the array, which are twice the orientation differences between the crystal elements reflecting them, are measured by recording the array at two or more mesh-to-photoplate distances. Maps of misorientation vectors over the crystal lattice planes under examination can be derived from these array images by visual or digital electronic metrological procedures. Applications to two specimens widely different in diffracting properties are described. Angular size of the X-ray source is the principal instrumental factor setting misorientation detection limits, and was less than 1 arc second in this work.