Design and investigation of absolute radiance calibration primary radiometer

In order to satisfy the requirement of calibration precision and traceability for space remote sensor, the absolute radiance calibration primary radiometer (ARCPR) is investigated for establishing the irradiance calibration standard in orbit. ARCPR is a mechanical cryogenic absolute radiometer for space application, and works at 20 K. The cryogenic environment is obtained by the Stryn-type pulse tube cryocooler. The environment temperature is stable at 23.9658 K by high-precision temperature controllers. The detector of ARCPR is designed and investigated based on the experimental prototype. The experimental results of detector characteristics measurement illustrate that the sensitivity is 3.9526 K/mW, and the thermal time constant is 134 s. The procedure of optical power measurement is optimised for satisfying the requirements of in orbit measurement. ARCPR achieves a relative standard uncertainty of 210 ppm at an optical power level of 0.4 mW. Therefore, ARCPR could be the radiometric standard for optical measurement. Furthermore, the investigation result provides the theoretical and experimental basis for the establishment of radiometric calibration standard in orbit.