Sagittal X-ray beam deviation at asymmetric inclined diffractors

A new approach to focusing X-ray optics based on asymmetric inclined (or ro tated inclined) diffraction has been experimentally studied. Using a linear longitudinal W-groove cut into the surface of an asymmetric silicon (111) diffractor perpendicularly to the line of intersection of its surface and c rystallographic (111) planes, the out-of-diffraction-plane (or sagittal) de viation of the X-ray diffracted beam has been measured for three angles of asymmetry and constant angle of inclination on BM5 at the ESRF for a wavele ngth of 0.1 nm. It has been demonstrated that in the grazing-emergence case the sagittal deviation increases with increasing asymmetry angle. A discre pancy with the theoretical value for the largest asymmetry angle and inhomo geneities in the contrast of the diffraction spot have been discussed.