Asymmetric-cut monochromator with adjustable asymmetry

摘要: Abstract A variable-incident-angle, asymmetric-cut, double-crystal monochromator with adjustable asymmetry was tested at Argonne National Laboratory to evaluate its possible use on beamlines the Advanced Photon Source. For both undulator and wiggler beams, can expand area of footprint beam surface crystals 50 times incident beam. This increase in will reduce angular distortions crystalline planes by a factor 2500. The asymmetric cut allows one acceptance angle for radiation obtain better match opening intensity diffracted 2 5. consists two matched, asymmetric-cut silicon mounted so that they be rotated independently about three different axes. Rotation around first axis controls Bragg angle. second between crystal horizontal plane make rectangle minimum length this area. third rotation is perpendicular diffraction carries crystal. amount being used thus surface. 18° matched pair crystals, which angles up 19.15° (6 keV Si[111] planes). monochromator, proper cooling, quite useful analyzing high X-ray beams produced undulators wigglers