BICEP2 observes on degree angular scales deep into the same patch of sky as BICEP1, employing cutting-edge technology to pack many more detectors onto the same size focal plane as BICEP1, thus dramatically increasing sensitivity. BICEP2 aims to measure the polarization of the cosmic microwave background (CMB) with better sensitivity than ever before.

The BICEP2 telescope is a small aperture, refracting telescope, allowing for precise control of systematic effects. The telescope optics are cooled to 4K. BICEP2 relies on the same principles as BICEP1, but with new detectors which allow for closer packing onto the focal plane. BICEP2 has 512 antenna-coupled TES bolometers in the focal plane. The focal plane is kept at 250 mK for CMB observations. Gaining detector sensitivity is critical in the search for "B-mode" polarization, and BICEP2 has an order of magnitude greater mapping speed than BICEP1.

The 512-detector BICEP2 focal plane and a zoom in of a dual polarization pixel with TES bolometer shown.

Beam of a single polarization of a single pixel.

This material is based upon work supported by the National Science Foundation.
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