Physikalisch-Technische Bundesanstalt

The UV and VUV Radiometry working group has its main focus on detector based radiometry and the characterization of materials and components concerning their optical properties in the wavelength range between 40 nm and 400 nm. For that purpose, a beamline at the Metrology Light Source (MLS) is operated, equipped with a 1 m normal incidence monochromator (NIM) to supply monochromatized synchrotron radiation in this range. For extension of the measurement capabilities, a new beamline for utilisation of monochromatized undulator radiation at the MLS is under development, for use with wavelengths beween 4 nm and 400 nm.

For the calibration of photodetectors with respect to their spectral responsivity, a cryogenic electrical substitution radiometer as primary detector standard is in use. At the same beamline, characterization of optical components (mirrors, filters, gratings) regarding their reflectance/transmittance or diffraction efficiency is performed using a reflectometer. Through scientific co-operations with collaborators from industry and research, the measurement capabilities can steadily be adapted to customer's needs, e. g., for characterization of space-based telescopes, or for characterization of optical materials.