A liquid-helium-cooled absolute reference cold load for long-wavelength radiometric calibration

• Main Authors: Bensadoun, Marc, Witebsky, Chris, Smoot, George, De Amici, Giovanni, Kogut, AL, Levin, Steve
• Format: Other/Unknown Material
• Language: unknown
• Published: 1992
• Subjects: 35; South Pole; Antarc*; Antarctica; South pole
• Online Access: http://ntrs.nasa.gov/search.jsp?R=19930053926

Design, radiometric and thermal performance, and operation of a large diameter (78 cm) liquid-helium-cooled blackbody absolute reference cold load (CL) for the calibration of microwave radiometers is described. CL provides an absolute calibration near the liquid-helium (LHe) boiling point, with total uncertainty in the radiometric temperature of less than 30 mK over the 2.5-23 cm wavelength operating range. CL was used at several wavelengths at the South Pole, Antarctica and the White Mountain Research Center, California. Results show that, for the instruments operated at 20-, 12-, 7.9-, and 4.0 cm wavelength at the South Pole, the total corrections to the LHe boiling-point temperature (about 3.8 K) were 48 +/-23, 18 +/-10, 10 +/-18, and 15 +/-mK.