Speaker
MASAYA HASEGAWA
(KEK)
Description
POLARBEAR is a ground-based CMB polarization experiment that is designed
to characterize the B-mode (curl component) signal both at degree and sub-degree
angular-scales. The degree-scale polarization data can be used for quantitative studies
on inflation, such as the reconstruction of the energy scale of inflation. The sub-degree
polarization data are an excellent tracer of large-scale structure in the universe,
and can be used to constrain the sum of the neutrino masses.
POLARBEAR-1 started observing in the early 2012 at 150 GHz with an array of 1274
polarization-sensitive antenna-coupled tansition-edge sensor (TES) bolometers,
and achieved the first detection of the sub-degree B-mode signal with CMB data alone.
The upgraded receiver (POLARBEAR-2) is being developed, and will be deployed
in 2016/2017 austral summer season in Atacama desert in Chile. The observation
with three POLARBEAR-2 type receivers (Simons Array project) will be started in 2018.
The Simons Array will create a detailed survey of B-mode polarization using
three arrays each of 7588 TES bolometer arrays, and will cover three frequency bands at
95, 150, 220 GHz for foreground control. The projected constraints on a tensor-to-scalar ratio (amplitude of inflationary B-mode signal)
is σ(r=0.1) = $6.0 \times 10^{-3}$ after foreground removal ($4.0 \times 10^{-3}$ (stat.)),
and the sensitivity to the sum of the neutrino masses when combined with DESI spectroscopic
galaxy survey data is 40 meV at 1-sigma after foreground removal (19 meV(stat.)).
In this presentation we will describe the current status and the prospects
of the POLARBEAR-2 receiver system and the Simons Array project.
Author
MASAYA HASEGAWA
(KEK)
