BOOMERANG Instrumentation

BOOMERANG, designed to measure anisotropies in the Cosmic Microwave Background (CMB), consists of an array of detectors cooled to 0.28 Kelvin mounted at the focus of a 1.3 meter telescope.  The instrument is flown on a gondola beneath a NASA/NSBF high altitude balloon. 

The BOOMERANG Dewar holds 60 liters of liquid helium, and the same amount of liquid nitrogen.  This cryostat stays cold for about 12 days with no servicing.  The light from the telescope enters the dewar through a window in the bottom.  
This Helium-3 refrigerator resides in the dewar.  The metal sphere is the charcoal pump.  The Helium-3 pot, which cools the detectors to 0.28 K, is the small metal cylinder in the lower part of the picture.  
This is the focal plane, with its feed horns, filters, and detectors.  This whole structure is cooled to 0.28 Kelvin.  The red cables are wires that carry signals from the detectors.
The BOOMERANG gondola, without its outer shielding. The dewar is at the center of the gondola, and the primary mirror is near the bottom underneath a blue protective cover.  The gondola hangs from the long duration balloon during the flight, and scans back and forth repeatedly over the selected observing field to map the CMB.
Here is a "CMB photon's view" of the telescope.  The primary mirror in the center focuses light up into the detectors in the dewar.  One of the windows to the dewar can be seen imaged in the primary mirror.  The large panels around the mirror and attached to the sides of the gondola keep light from the earth and sun from interfering with our measurements.

Copyright by the BOOMERANG Collaboration

Last update: 04/25/2000