Description of the payload

The Background Emission Anisotropy Scanning Telescope (BEAST) is a millimeter wavelength experiment designed to generate maps of fluctuations in the cosmic microwave background (CMB). The primary reflector (the largest flown on a stabilized balloon platform) is a 2.2 m off-axis parabolic reflector that receives its input beam from a rotating flat reflector of 2.6 m in diameter. The telescope focuses the collected microwave radiation onto an array of cryogenically cooled high electron mobility transistor (HEMT) receivers. This array is composed of six corrugated scalar feed horns in the Q band (38 to 45 GHz) and two more in the Ka band (26 to 36 GHz) with one of the six Q-band horns connected to an ortho-mode transducer for extraction of both polarizations incident on the single feed.

Details of the balloon flight and scientific outcome

Launch site: Scientific Flight Balloon Facility, Fort Sumner, (NM), US  
Balloon launched by: National Scientific Balloon Facility (NSBF)
Balloon manufacturer/size/composition: Zero Pressure Balloon Raven - 11.820.000 cuft - SF3-317.60-080-NSCHR-03-ST
Balloon serial number: W11.82-3-04
Flight identification number: 492N

This was the second flight of the instrument. It had a number of different problems, but the flight was only about 5-6 hr at float, and the detector sensitivity, along with the scan, generated pixel error bars that were too great to make a useful CMB map.

Subsequent to this second flight BEAST, was reconfigured to take advantage of the University of California White Mountain Research Station, located at an altitude of 3800 meters in the Eastern Sierra of California.

External references and bibliographical sources

Images of the mission