X-ray diffraction on Si single crystal with a W-shaped longitudinal groove

The measurement of the sagittal deviation of an X-ray beam diffracted on th e inclined surface of an Si(111) single crystal was performed on beamline B M5 at the ESRF, with lambda = 0.1 nm and an inclination angle, beta, of 70 degrees. The measured value agrees with the theory developed in previous pa pers. The topographic picture of the longitudinal edge shows a structure th at can be explained in terms of the properties of inclined diffraction.