POLARBEAR is a cosmic microwave background (CMB) experiment situated on the 3.5-meter diameter Huan Tran Telescope at the James Ax Observatory located at Cerro Toco in the Atacama Desert in Northern Chile (image above by POLARBEAR collaboration). It is designed to make measurements of the CMB polarization on small angular scales in order to detect the B-mode polarization and put limits on inflation. Additionally, a second objective is to reconstruct the lensing potential of the CMB with hopes of providing limits on the neutrino mass.
The first POLARBEAR receiver was deployed to the Huan Tran Telescope in 2012. It contains 1274 antenna-coupled TES bolometers observing at 150 GHz. Current science results include: