Monochromator paper (PDF document - 236 KB)

A high-precision cryogenically-cooled crystal monochromator has been developed for the APS diagnostics beamline. The design permits simultaneous measurements of the particle beam size and divergence. It provides for a large rotation angle, -15.... to 180...., with a resolution of 0.0005..... The roll angle of the crystal can be adjusted by up to ±3.... with a resolution of 0.0001..... A vertical translational stage, with a stroke of ±25 mm and resolution of 8 µm, is provided to enable using different parts of the same crystal or to retract the crystal from the beam path. The modular design will allow optimization of cooling schemes to minimize thermal distortions of the crystal under high heat loads.