Low-temperature blackbodies and facility for calibration of them

The calibration of IR sensors, thermal imagers, instrumentation for remote earth sensing, signature recognition, and low background spacebome radiometers requires development of low- and near-ambient-temperature reference standard sources capable of operating in vacuum at low or medium background conditions. The paper contains the characteristics of blackbodies (BB), developed at the All-Russian Research Institute for Optical and Physical Measurements (VNIIOFI). A novel Medium Background Facility (MBF) intended for calibrating IR sources has been developed at VNIIOFI. The MBF used for the calibration under vacuum conditions (10(-3) Pa) and medium background temperatures includes a Ga Fixed-Point Blackbody (29.76degreesC), Variable Temperature Blackbody (-60degreesC similar to + 80degreesC) and Filter Radiometer. A brief description of the operating principles and specifications of the MBF is presented. The results of a comparison of the Variable Temperature Blackbody and Ga Fixed Point Blackbody in the Medium Background Facility are given. The measurement uncertainties radiance temperature associated with spectral bandwidth are discussed.