POLARBEAR-2: an instrument for CMB polarization measurements
  POLARBEAR-2 (PB-2) is a cosmic microwave background (CMB) polarization
experiment that will be located in the Atacama highland in Chile at an altitude
of 5200 m. Its science goals are to measure the CMB polarization signals
originating from both primordial gravitational waves and weak lensing. PB-2 is
designed to measure the tensor to scalar ratio, r, with precision {\sigma}(r) <
0.01, and the sum of neutrino masses, {\Sigma}m{\nu}, with
{\sigma}({\Sigma}m{\nu}) < 90 meV. To achieve these goals, PB-2 will employ
7588 transition-edge sensor bolometers at 95 GHz and 150 GHz, which will be
operated at the base temperature of 250 mK. Science observations will begin in
2017.
