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To meet the increasing demand of calibrations in the field of radiation thermometry, the Physikalisch-Technische Bundesanstalt (PTB) operates two different setups for calibrations covering the temperature range from-60 C up to 3000 C. The first setup consists of several heat-pipe blackbodies in conjunction with platinum resistance thermometers, calibrated according to the International Temperature Scale of 1990 (ITS-90) and is applied for calibrations in the temperature range from-60 C to 961.78 C. In the temperature range from 962 C to 3000 C the calibration is based on high temperature blackbodies. The temperature of these blackbodies is determined in two independent ways: traceable to the ITS-90 gold fixed point or via absolutely calibrated filter radiometers (FR) traceable to the detector primary standard, the cryogenic radiometer. Taking advantage from the high accuracy of the FR calibration, these FRs have also been successfully used for the investigation of the thermodynamic accuracy of the ITS-90 in the range from 419 C to 962 C. For non-contact temperature measurements, the emissivity of the observed object is one of the most important parameters. Therefore, PTB has set up instrumentations for measuring the directional spectral and total emissivity of samples in air from 80 C up to 400 C over a spectral range from 4 µm to 40 µm and under vacuum from 0 C to 600 C and in the spectral range from 1 µm to 1000 µm.
The Physikalisch-Technische Bundesanstalt (PTB) has developed dedicated instrumentations and methods for the traceable calibration of space borne instruments in terms of the three fundamental radiometric units, i.e. spectral radiance (radiation temperature), spectral radiant intensity and spectral photon flux. The traceable calibration under conditions similar to the space environment is achieved by use of two major radiometric calibration facilities of PTB, the Spectral Radiance Comparator Facility (SRCF) and the Reduced Background Calibration Facility (RBCF) which are part of the Primary Temperature Radiator Facility of PTB and cover the wavelength range from the UV to the FIR (THz range). The improved detector instrumentations of the SRCF and RBCF, detailed calibration schemes and results of calibrations for space missions are presented.