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

We have observed x-ray speckle at grazing incidence from gold-coated films of symmetric diblock copolymers of polystyrene (PS) and polymethylmethacrylate (PMMA). The polymer films consisted of micron-sized islands on a uniform surface. Coherent 6-keV photons were selected by monochromatizing and collimating the x-ray beam from a bending magnet synchrotron source. The visibility of the speckle patterns was enhanced with increasing degrees of spatial coherence of the photons. Speckles due to coherent scattering from islands with length scales up to 100 mum were clearly identified.