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Radiometer system to map the cosmic background radiationA 33-GHz airborne radiometer system has been developed to map large angular scale variations in the temperature of the 3 K cosmic background radiation. A ferrite circulator switches a room-temperature mixer between two antennas pointing 60 deg apart in the sky. In 40 min of observing, the radiometer can measure the anisotropy of the microwave background with an accuracy of plus or minus 1 mK rms, or about 1 part in 3000 of 3 K. The apparatus is flown in a U-2 jet to 20 km altitude where 33-GHz thermal microwave emission from the atmosphere is at a low level. A second radiometer, tuned to 54 GHz near oxygen emission lines, monitors spurious signals from residual atmospheric radiation. The antennas, which have an extremely low side-lobe response of less than -65 dB past 60 deg, reject anisotropic radiation from the earth's surface. Periodic interchange of the antenna positions and reversal of the aircraft's flight direction cancel equipment-based imbalances. The system has been operated successfully in U-2 aircraft flown from NASA-Ames at Moffett Field, Calif.
Document ID
19780046782
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Gorenstein, M. V.
(California Univ. Berkeley, CA, United States)
Muller, R. A.
(California Univ. Berkeley, CA, United States)
Smoot, G. F.
(California, University Berkeley, Calif., United States)
Tyson, J. A.
(California Univ. Berkeley, CA, United States)
Date Acquired
August 9, 2013
Publication Date
April 1, 1978
Publication Information
Publication: Review of Scientific Instruments
Volume: 49
Subject Category
Instrumentation And Photography
Accession Number
78A30691
Funding Number(s)
CONTRACT_GRANT: W-7405-ENG-48
CONTRACT_GRANT: NSG-2125
Distribution Limits
Public
Copyright
Other

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