Optical design and commissioning results of a constant-imaging-distance fixed-included-angle grating monochromator at SSRF.

A constant-imaging-distance fixed-included-angle grating monochromator has been designed and constructed at the Shanghai Synchrotron Radiation Facility to expand the covered energy range of the X-ray test beamline. The design and first commissioning results are presented in this paper. Initial results reveal the good performance of this monochromator, with a photon energy resolving power estimated to be over 8000 at the krypton M-edge for high line density gratings and a -1st order diffraction efficiency of the grating better than 30% for low line density gratings.