Measurement of the cosmic background radiation temperature at 3. 3 mm wavelength

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1985

OSTI ID:6021550

Witebsky, C

Measurements of the cosmic background radiation (CBR) at 3.3 mm wavelength (90 GHz) yielded a brightness temperature of 2.57 K with a 1sigma uncertainty of +/-0.12 K. The observations were made from the Barcroft Laboratory of the White Mountain Research Station, at an altitude of 3800 m, initially on 5 and 6 July 1982 and again on 4, 5 and 6 September 1983, as part of a program to measure the spectrum of the CBR at five wavelengths from 12.0 cm to 3.3 mm. The weighted mean of the temperature measurements at all five wavelengths is 2.72 +/- 0.04 K. The instrument used for the 3.3 mm measurements is a differential, dual-antenna, Dicke-switched, superheterodyne radiometer with an RF bandwidth of 1.9 GHz and a sensitivity of 125 mK/..sqrt..Hz. The radiometer is mounted on bearings, which allow it to rotate. Either antenna can view a large liquid-helium-cooled absolute reference load while the other antenna views the zenith. The antenna temperature of the reference load, 2.083 +/- 0.037 K, is added to the measured zenith/cold-load temperature difference to yield the zenith antenna temperature, typically 9 to 12 K. The atmospheric contribution to the zenith temperature is measured by means of zenith scans.

• Research Organization: California Univ., Berkeley (USA)
• OSTI ID: 6021550
• Country of Publication: United States
• Language: English

Related Subjects

640100* -- Astrophysics & Cosmology
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BACKGROUND RADIATION
BRIGHTNESS
COSMIC RADIATION
DATA
EXPERIMENTAL DATA
INFORMATION
IONIZING RADIATIONS
MEASURING INSTRUMENTS
NUMERICAL DATA
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RADIATION DETECTORS
RADIATIONS
RADIOMETERS
TEMPERATURE MEASUREMENT