High-accuracy detector calibration at the PTB four-crystal monochromator beamline

A four-crystal monochromator beamline has been installed by the Physikalisc h-Technische Bundesanstalt at a bending magnet of the electron storage ring BESSY II. The monochromatic radiation with very high spectral purity and h igh spectral resolution in the photon energy range from 1.75 to 10keV is us ed to calibrate detectors by comparison to a cryogenic electrical substitut ion radiometer as primary detector standard with relative uncertainties wel l below 1%, This is one order of magnitude better than all calibrations of non-energy-dispersive detectors in this spectral range previously performed . The beamline is also used for the characterization of optical components. (C) 2001 Elsevier Science B.V. All rights reserved.