Anomalous X-ray transmission through sapphire crystals

The triple-crystal X-ray diffractometry of anomalous X-Ray transmission is used to investigate sapphire single crystals grown in protective gaseous media with the help of the horizontal directional-crystallization method. The dependences between the integral intensities of anomalously transmitted and Bragg-Laue reflected X-ray beams (T _i and R _i , respectively) and the thickness of the samples under study, which enable us to determine regions of thin- and thick-crystal approximation, have been obtained at 2.52 ≤ μt ≤ 18.9. The integral coefficient μ _i of interference absorption and the integral characteristic y _i are calculated in the dynamic thick-crystal approximation. It is demonstrated that dislocations are distributed mainly within the small-angle boundaries of a grown sapphire crystal. It is ascertained that the parameter μ _i is highly sensitive to the dislocation density and the pattern of the dislocation distribution in a crystal.