MEASURING METHOD FOR LATTICE DISTORTION OF CRYSTAL

PROBLEM TO BE SOLVED: To provide a method for detecting the correct lattice deflection of a crystal by correcting a nonuniform diffracted X-ray intensity distribution of an X-ray topograph that is not derived from the crystallinity of a sample crystal. SOLUTION: This measuring method uses an X-ray topograph taking optical system to take an X-ray topograph and, at the same time, measures a diffracted X-ray intensity curve. Next, the difference in Bragg condition of a sample crystal is calculated from the diffracted X-ray intensity curve, the peak intensity fluctuations of the diffracted X-ray intensity curve in continuous regions are calculated, and using these values, the diffracted X-ray intensity distribution of the X-ray topograph of the sample crystal is corrected; the fluctuation ratio Δd/(d) of the lattice spacing and the fluctuation Δα of the lattice azimuth, both of which do not contain components which are not derived from crystallinity, from the diffracted X-ray intensity distribution corrected are calculated.