The new cryogenic vacuum chamber and black-body source for infrared calibrations at the NIST's FARCAL facility

The Facility for Advanced Radiometric Calibrations (FARCAL) at the National Institute of Standards and Technology (NIST) in Gaithersburg, MD, comprise s the Medium Background Infrared (MBIR) facility and the Training for Calib ration Expertise in Radiometry (TraCER), the latter being a classroom setti ng. The MBIR is a 120 cm by 180 cm vacuum chamber with an internal cold shr oud and an integral roll-out table. The chamber will contain a black-body s ource and an absolute cryogenic radiometer (ACR). Both components are mount ed on the roll-out table. Measurements will be performed in the MBIR facili ty that cannot be accomplished using existing facilities, including the NIS T Low Background Infrared (LBIR) facility and the room-temperature non-vacu um radiometric facilities. Initially the MBIR facility will be used for 80 K medium background measurements and 300 K ambient background measurements.