POLARBEAR-2 (PB-2) is a cosmic microwave background (CMB) polarization experiment observing at Atacama plateau in Chile. PB-2 is designed to improve the sensitivity to measure the CMB B-mode polarization by upgrading the current POLARBEAR-1 receiver that is currently mounted on the Huan Tran telescope. The improvements in PB-2 include, i) the dual band observations at 95 GHz and 150 GHz in each pixel using an sinuous antenna, ii) the increase of the total number of detectors, 7588 Al-Ti bilayer transition-edge sensor (TES) bolometers, iii) the bath temperature of bolometers at 100mK in the second phase of observation (300mK in the first phase.) With the expected sensitivity of 5.7 μK √ s, PB-2 is sensitive to a tensor-to-scalar ratio, r, of 0.01 at 95% confidence level (CL) and constrains the sum of neutrino masses as 90meV by PB-2 alone and 40meV by combining PB-2 and Planck at 68% CL. We schedule to deploy in 2014.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Takayuki Tomaru ; Masashi Hazumi ; Adrian T. Lee ; Peter Ade ; Kam Arnold, et al.
"The POLARBEAR-2 experiment", Proc. SPIE 8452, Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VI, 84521H (September 24, 2012); doi:10.1117/12.926158; http://dx.doi.org/10.1117/12.926158