TRANSFORMATION OF X-RAY-POLARIZATION UNDER DYNAMICAL GRAZING-INCIDENCE DIFFRACTION

The transformation of the X-ray polarization under grazing incidence d iffraction is studied. The dependencies of the parameters of the polar ization ellipses for specularly reflected and diffracted waves in vacu um on the corresponding parameters of the incident wave with arbitrary polarization are found. Strong spatial crystal anisotropy close to th e exact Bragg condition and the existence of two critical reflection a ngles manifest themselves in a steep change of the polarization state of the secondary waves near these points. It is shown that diffraction conditions exist such that an incident linearly polarized beam of X-r ay quanta can acquire a high degree of circular polarization during th e reflection process.