The POLARBEAR-2 experiment

A. Suzuki, P. Ade, Y. Akiba, C. Aleman, K. Arnold, M. Atlas, D. Barron, J. Borrill, S. Chapman, Y. Chinone, A. Cukierman, M. Dobbs, T. Elleflot, J. Errard, G. Fabbian, G. Feng, A. Gilbert, W. Grainger, N. Halverson, M. HasegawaK. Hattori, M. Hazumi, W. Holzapfel, Y. Hori, Y. Inoue, G. Jaehnig, N. Katayama, B. Keating, Z. Kermish, R. Keskitalo, T. Kisner, A. Lee, F. Matsuda, T. Matsumura, H. Morii, S. Moyerman, M. Myers, M. Navaroli, H. Nishino, T. Okamura, C. Reichart, P. Richards, C. Ross, K. Rotermund, M. Sholl, P. Siritanasak, G. Smecher, N. Stebor, R. Stompor, J. Suzuki, S. Takada, S. Takakura, T. Tomaru, B. Wilson, H. Yamaguchi, O. Zahn

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


We present an overview of the design and development of the POLARBEAR-2 experiment. The POLARBEAR-2 experiment is a cosmic microwave background polarimetry experiment, which aims to characterize the small angular scale B-mode signal due to gravitational lensing and search for the large angular scale B-mode signal from inflationary gravitational waves. The experiment will have a 365 mm diameter multi-chroic focal plane filled with 7,588 polarization sensitive antenna-coupled Transition Edge Sensor bolometers and will observe at 95 and 150 GHz. The focal plane is cooled to 250 mK. The bolometers will be read-out by SQUIDs with 32 × frequency domain multiplexing. The experiment will utilize high purity alumina lenses and thermal filters to achieve the required high optical throughput. A continuously rotating, cooled half-wave plate will be used to give stringent control over systematic errors. The experiment is designed to achieve a noise equivalent temperature of 5.7μK√s, and this allows us to constrain the signal from the inflationary primordial gravitational corresponding to a tensor-to-scalar ratio of r = 0.01 (2σ). POLARBEAR-2 will also be able to put a constraint on the sum of neutrino masses to 90 meV (1σ) with POLARBEAR-2 data alone and 65 meV (1σ) when combined with the Planck satellite. We plan to start observations in 2014 in the Atacama Desert in Chile.

Original languageEnglish
Pages (from-to)719-725
Number of pages7
JournalJournal of Low Temperature Physics
Issue number5-6
StatePublished - Sep 2014


  • B-mode
  • Cosmic microwave background
  • Inflation
  • Lensing
  • Polarization


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