Two-dimensional intensity distribution in high-angle double-crystal X-ray diffractometry (HADOX)

Two slits have been introduced into high-angle double-crystal X ray diffractometry (HADOX): one for limiting the area of the specimen surface to be examined, and the other for defining the resolution of 2θ. This enables us to combine co and 2θ scannings, and to obtain two-dimensional intensity distribution in high resolution on a reciprocal lattice plane parallel to the plane of the diffractometer. By this method, we can determine the temperature dependence of the lattice constant of the specimen crystal without being disturbed by an influence of surroundings, for expample, a distortion of a specimen holder. Moreover, measurements of the lattice constant can be made on a crystal that consists of grains. Applications are made for BaTi03 crystals in connection with the characterization and with the study of the structural phase transition.