Receiver development for BICEP Array, a next-generation CMB polarimeter at the South Pole

L. Moncelsi , P.A. R. Ade , Z. Ahmed , M. Amiri , D. Barkats , R. Basu Thakur , C.A. Bischoff , J.J. Bock , V. Buza , J. Cheshire , J. Connors , J. Cornelison , M. Crumrine , A. Cukierman , E.V. Denison , M. Dierickx , L. Duband (1) , M. Eiben , S. Fatigoni , J.P. Filippini , N. Goeckner-Wald , D.C. Goldfinger , J. Grayson , P. Grimes , G. Hall , M. Halpern , S. Harrison , S. Henderson , S.R. Hildebrandt , G.C. Hilton , J. Hubmayr , H. Hui , K.D. Irwin , J. Kang , K.S. Karkare , S. Kefeli , J.M. Kovac , C.L. Kuo , K. Lau , E.M. Leitch , K.G. Megerian , L. Minutolo , Y. Nakato , T. Namikawa , H.T. Nguyen , R. O'Brient , S. Palladino , N. Precup , T. Prouve (2) , C. Pryke , B. Racine , C.D. Reintsema , A. Schillaci , B.L. Schmitt , A. Soliman , T. St Germaine , B. Steinbach , R.V. Sudiwala , K.L. Thompson , C. Tucker , A.D. Turner , C. Umiltà , A.G. Vieregg , A. Wandui , A.C. Weber , D.V. Wiebe , J. Willmert , W.L. K. Wu , E. Yang , K.W. Yoon , E. Young , C. Yu , L. Zeng , C. Zhang , S. Zhang

1 DSBT - Département des Systèmes Basses Températures
2 LCCS - Laboratoire des Cryoréfrigérateurs et Cryogénie Spatiale

A detection of curl-type (B-mode) polarization of the primary CMB would be direct evidence for the inflationary paradigm of the origin of the Universe. The Bicep/Keck Array (BK) program targets the degree angular scales, where the power from primordial B-mode polarization is expected to peak, with ever-increasing sensitivity and has published the most stringent constraints on inflation to date. Bicep Array (BA) is the Stage-3 instrument of the BK program and will comprise four Bicep3-class receivers observing at 30/40, 95, 150 and 220/270 GHz with a combined 32,000+ detectors; such wide frequency coverage is necessary for control of the Galactic foregrounds, which also produce degree-scale B-mode signal. The 30/40 GHz receiver is designed to constrain the synchrotron foreground and has begun observing at the South Pole in early 2020. By the end of a 3-year observing campaign, the full Bicep Array instrument is projected to reach σ_r between 0.002 and 0.004, depending on foreground complexity and degree of removal of B-modes due to gravitational lensing (delensing). This paper presents an overview of the design, measured on-sky performance and calibration of the first BA receiver. We also give a preview of the added complexity in the time-domain multiplexed readout of the 7,776-detector 150 GHz receiver.

Mots clés: Cosmic Microwave Background; polarization; Instrumentation; Cosmology; B-Modes; Inflation; lensing; synchrotron; beam: polarization; gravitation: lens; BICEP; cosmic background radiation; inflation; detector: calibration; detector: sensitivity; detector: performance; readout; galaxy; B-mode; optics; detector: cryogenics; cosmic background radiation: polarization

Domaines: Instrumentations et Détecteurs [physics.ins-det]; Astrophysique [astro-ph]

L. Moncelsi, P.A. R. Ade, Z. Ahmed, M. Amiri, D. Barkats, et al.. Receiver development for BICEP Array, a next-generation CMB polarimeter at the South Pole. SPIE Astronomical Telescopes + Instrumentation 2020, Dec 2020, Online, United States. pp.1145314, ⟨10.1117/12.2561995⟩. ⟨hal-03143663⟩