A NEW APPROACH FOR MAPPING X-RAY ROCKING CURVES

A new experimental geometry for simultaneously mapping the rocking cur ves of a sample over a one- or two-dimensional array of points on the sample has been developed. The 422 asymmetric diffraction of Cu K(alph a1) radiation with a monolithic channel-cut silicon crystal angularly collimates and spatially expands the x-ray beam. A cooled Reticon line ar photodiode array with 25-mum spatial resolution was used for the on e-dimensional detector. Compared with the commonly used double-crystal diffractometer method, more information can be obtained from the pres ent method, for example, characterization of the minute local misorien tation of subgrains and the precise determination of the curvature of a crystal. The uniformity of the crystal quality and the local variati on of the curvature of the crystal planes over a sample can also be re vealed from the contour map of the rocking curves. Maps of the rocking curves of several samples have been collected using this method.