The phenomenon of polarization suppression of X-ray Umweg multiple waves in crystals

The phenomenon of the polarization suppression of X-ray Umweg multiple wave s in Renninger scans [Renninger (1937). Z. Kristallogr. 97, 107-121] of cry stals, showing intensity decrease due to properly chosen wavelength and pol arization of incident radiation, is observed. That is, one of the participa ting wave components in the multiple-wave interference is reduced considera bly so that the intensity of multiple diffraction is decreased. The conditi on for total suppression of the multiple-wave interaction in crystals is de rived theoretically from the Born approximation and verified with exact dyn amical calculation and experiments. Partial suppression of the strong Umweg interfered component is demonstrated using elliptically or linearly polari zed synchrotron radiation. The suppressed multiple-wave intensity distribut ion reveals high sensitivity to X-ray reflection phase. This multiple-diffr action technique under partial polarization suppression provides an alterna tive way of enhancing the visibility of multiple-wave interference in cryst als for direct phase determination.