Detector calibration at the radiometry laboratory of the Physikalisch-Technische-Bundesanstalt in the VUV and soft x-ray spectral ranges using synchrotron radiation

摘要

In the vacuum ultraviolet and soft x-ray spectral ranges the radiometry laboratory of the Physikalisch-Technische Bundesanstalt at the synchrotron radiation facility BESSY offers two different methods for the calibration of radiation detectors. The electron storage ring BESSY, in combination with suitable monochromators, reproducible produces monochromatic radiation of tunable photon energy, high spectral purity, and high radiant power which can be reduced by twelve orders of magnitude. With this source of monochromatic radiation a cryogenic electrical substitution radiometer (ESR) is operated as a primary detector standard in the photon energy range from 3 eV to 1500 eV. The ESR is optimized for synchrotron radiation, capable of measuring radiant power in the order of some $mu@W with an uncertainty below 0.2%. Radiation detectors can be calibrated against the ESR with uncertainties well below 1%. Recent progress in this field will be demonstrated for the calibration of photodiodes. The electron storage ring BESSY is also used as a primary source standard, in the photon energy range from the infrared to the soft x-ray range. The spectral and spatial distribution of the broadband radiation, emitted in the range from 1 eV to 15 keV, is calculable from the known storage ring parameters with uncertainties from 0.04% to 0.35%, respectively. This allows the detection efficiency of energy-dispersive detectors such as solid-state detectors, charge- coupled devices, and others to be determined, provided the detector response function to monochromatic radiation is measured as well.