BICEP3, the successor to BICEP2, was deployed to the Dark Sector Laboratory at Amundsen-Scott South Pole Station in the 2014-2015 Austral summer season. It was upgraded in 2015-2016 to a full 2560 detectors operating at 95 GHz, and currently complements Keck Array observations in 150 GHz and 220/270 GHz bands.
Like previous telescopes in the BICEP series, BICEP3 is a wide-field
cryogenic refractor, but with a 55cm aperture and fast optics it
achieves an order of magnitude increase in throughput. Its design and
performance are described in
BICEP3 is a prototype for the four BICEP3-sized receivers of the BICEP Array, which will replace Keck Array over the next several years and will include a total of over 30,000 detectors in five frequency bands.