Calibration of charge coupled devices and a pinhole transmission grating to be used as elements of a soft x-ray spectrograph

The development of new types of sophisticated soft x-ray sources requires the knowledge of their emission characteristics such as photon flux, spectral distribution, and size of the radiation source. Calibrated spectrographs for the soft x-ray region are needed to determine these properties. The components of a soft x-ray spectrograph consisting of a pinhole gold transmission grating and a charge coupled device (CCD) camera are calibrated at the radiometry laboratory of the Physikalisch-Technische Bundesanstalt using the synchrotron radiation facility BESSY. Two different kinds of CCD-based photon detectors (one thinned and back illuminated, one coated with a phosphorous layer) are compared with regard to their sensitivities in the spectral range between 50 eV and 1.7 keV. The results obtained for the thinned CCD are compared with theoretical calculations of the sensitivity.