OBSERVATION OF X-RAY SPECKLE BY COHERENT SCATTERING AT GRAZING-INCIDENCE

We have observed x-ray speckle at grazing incidence from gold-coated f ilms of symmetric diblock copolymers of polystyrene (PS) and polymethy lmethacrylate (PMMA). The polymer films consisted of micron-sized isla nds on a uniform surface. Coherent 6-keV photons were selected by mono chromatizing and collimating the x-ray beam from a bending magnet sync hrotron source. The visibility of the speckle patterns was enhanced wi th increasing degrees of spatial coherence of the photons. Speckles du e to coherent scattering from islands with length scales up to 100 mum were clearly identified.