Experimentally determined resolution of a six meter toroidal grating monochromator

Abstract

The resolution of a 6-m toroidal grating monochromator (TGM), installed at the University of Wisconsin Synchrotron Radiation Center (SRC), is experimentally determined. Narrow resonance lines of He, Ne, Ar, Kr and Xe in the 8–73 eV energy range were used to measure the resolution. The experimental resolution is compared with that obtained using a ray-tracing program SHADOW, in which theoretical mirror and grating specifications were used. Agreement between the experimental data and ray-tracing calculations is excellent. The effects of masking the grating and limiting the horizontal acceptance of the entrance and exit slits are also examined. Finally, it was found during the resolution measurements that the higher-order components contribute significantly to the amount of light obtained at a given grating position. For the low-energy grating, assuming only first- and second-order light, 70% of the light is first-order and 30% is second-order at a given grating position. For the medium energy grating, 80% of the light is first-order and 20% is second-order.