POLARBEAR-2: an instrument for CMB polarization measurements

TL;DR

POLARBEAR-2 is a high-altitude CMB polarization experiment designed to measure primordial gravitational waves and neutrino masses with high precision using thousands of sensitive bolometers.

Contribution

This paper introduces the POLARBEAR-2 instrument, detailing its design, goals, and capabilities for advancing CMB polarization measurements.

Findings

Designed to measure tensor-to-scalar ratio r with σ(r)<0.01

Aims to determine neutrino mass sum with σ(Σmν)<90 meV

Employs 7588 transition-edge sensor bolometers at 95 and 150 GHz

Abstract

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.