A bent Laue crystal monochromator for monochromatic radiography with an area beam

A bent Laue crystal monochromator which can diffract a large area of monochromatic X-rays from a polyenergetic X-ray rotating-anode source has been developed at the National Synchrotron Light Source (NSLS). The monochromatic beam, with a solid angle of more than 5 degrees x 5 degrees and energy range tunable from 15 to 100keV, is completely separated from the white beam at a distance of less than Im from the source. The absolute reflectivity of the monochromator ranges from 10% to 40% (depending on the energy of the X-rays being diffracted and the source size). The energy bandwidth of around 2% is controllable by varying the diffraction planes used, the crystal thickness, asymmetry angle and the bending radius. A single emission line from an X-ray tube source can be selectively diffracted into the entire exit-beam solid angle. Potential applications of the device in clinical radiography are discussed.