Medium-background radiometric facility for calibration of sources or sensors

A new Medium-Background Facility (MBF) for the calibration of infrared sour ces and sensors has been designed by specialists from the All-Russian Resea rch Institute for Optophysical Measurements (VNIIOFI) under contract to the Xi'an Institute of Applied Optics (China). The facility consists of severa l detachable modules, the configuration of which can be changed to suit the requirements of a specific task. The modular design allows flexible and in dependent use of the main components and simplifies upgrading. The facility was designed to allow absolute radiometric calibration of black-body sourc es and IR sensors; to compare the radiometric scale with predictions for me asured temperatures; to allow measurements over an extended temperature ran ge (up to the indium point); and to serve as the IR spectral radiance stand ard. Intended for the calibration of IR sensors and sources under vacuum co nditions (10(-3) Pa) and a medium-background environment (liquid-nitrogen-c ooled shroud), the MBF is briefly described with reference to its design, o perating principles and measurement results.