Quality Assessment of Sapphire Wafers for X-Ray Crystal Optics Using White Beam Synchrotron X-Ray Topography

Abstract

The white beam Synchrotron X-Ray Topography (SXRT) technique was used to assess the quality of sapphire wafers grown by the Heat-Exchanger Method (HEM) and the Modified Czochralski Method (MCM). Sapphire is a potential new material for X-ray crystal optics, especially for use as Bragg backscattering mirrors for X-rays and Mössbauer radiation. The dislocation distribution, dislocation density and Burgers vector of selected dislocations and stacking faults in the sapphire wafers were studied. A correlation between the sapphire quality and its performance as an X-ray backscattering mirror was established in this paper. The results reveal the high quality of the inspected HEM sapphire wafers and their subsequently improved performance as Bragg backscattering mirrors.