Atacama B-Mode Search

The Atacama B-Mode Search is a radio telescope in the Atacama Desert operating at 5200 meters elevation with 240 polarization-sensitive detectors at 145 GHz frequency. The instrument was specifically designed to map polarization patterns in the cosmic microwave background radiation.

The installation was established in 2012 and collected data through October 2014 on polarization patterns from the early universe. It aimed to investigate cosmic inflation theories and provided important information about the structure of the early cosmos.

Multiple research institutions, including Princeton University, Johns Hopkins University, and Chilean organizations, formed an international coalition to operate this advanced cosmic observatory.

The entire telescope system fits within a standard shipping container, which enabled transport to this remote location in northern Chile's high-altitude desert. The high elevation and dry conditions make this site suitable for observing the cosmic background.

The system uses a rotating sapphire half-wave plate at room temperature spinning at 2.55 Hz to separate atmospheric noise from cosmic signals. This innovative design allows the instrument to detect extremely faint polarization signals from space.

Location: Atacama Desert

Elevation above the sea: 5,200 m

Website: http://princeton.edu/physics/research/cosmology-experiment/abs-experiment

GPS coordinates: -22.95970,-67.78720

Latest update: December 13, 2025 17:09