Open-faced Z-shaped channel-cut x-ray monochromator

Channel-cut monochromators can be easily incorporated in high-resolution image techniques. However, polishing on the inner diffracting surfaces is difficult because of blockage by the opposite face. To address this difficulty, an open-faced monolithic monochromator has been designed, produced and tested using x-rays at the Advanced Photon Source (APS). The open-faced channel cut has a "Z"-shape geometry with a hole in the mid section to allow passage of the diffracted beam. The open geometry allowed chemical mechanical polishing so that an optically smooth finish on both surfaces was achieved. The high-resolution x-ray imaging and topography measurements revealed that the new design introduces significantly less distortions in the phase-contrast images compared with conventional channel-cut monochromators produced using etching alone.