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QUBIC: the Q and U bolometric interferometer for cosmology

O'Sullivan, C. and Schillaci, A. (2018) QUBIC: the Q and U bolometric interferometer for cosmology. In: Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy IX. Proceedings of SPIE. No.10708. Society of Photo-optical Instrumentation Engineers (SPIE) , Bellingham, WA, Art. No. 107082B. ISBN 9781510619692.

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QUBIC, the Q & U Bolometric Interferometer for Cosmology, is a novel ground-based instrument that has been designed to measure the extremely faint B-mode polarisation anisotropy of the cosmic microwave background at intermediate angular scales (multipoles of l = 30 - 200). Primordial B-modes are a key prediction of Inflation as they can only be produced by gravitational waves in the very early universe. To achieve this goal, QUBIC will use bolometric interferometry, a technique that combines the sensitivity of an imager with the systematic error control of an interferometer. It will directly observe the sky through an array of 400 back-to-back entry horns whose signals will be superimposed using a quasi-optical beam combiner. The resulting interference fringes will be imaged at 150 and 220 GHz on two focal planes, each tiled with NbSi Transition Edge Sensors, cooled to 320 mK and read out with time-domain multiplexing. A dichroic filter placed between the optical combiner and the focal planes will select the two frequency bands. A very large receiver cryostat will cool the optical and detector stages to 40 K, 4 K, 1 K and 320 mK using two pulse tube coolers, a novel 4He sorption cooler and a double-stage 3He/4He sorption cooler. Polarisation modulation and selection will be achieved using a cold stepped half-wave plate (HWP) and polariser, respectively, in front of the sky-facing horns. A key feature of QUBIC’s ability to control systematic effects is its ‘self-calibration’ mode where fringe patterns from individual equivalent baselines can be compared. When observing, however, all the horns will be open simultaneously and we will recover a synthetic image of the sky in the I, Q and U Stokes’ parameters. The synthesised beam pattern has a central peak of approximately 0.5 degrees in width, with secondary peaks further out that are damped by the 13-degree primary beam of the horns. This is Module 1 of QUBIC which will be installed in Argentina, near the city of San Antonio de los Cobres, at the Alto Chorrillos site (4869 m a.s.l.), Salta Province. Simulations have shown that this first module could constrain the tensor-to-scalar ratio down to σ(r) = 0.01 after a two-year survey. We aim to add further modules in the future to increase the angular sensitivity and resolution of the instrument. The QUBIC project is proceeding through a sequence of steps. After an initial successful characterisation of the detection chain, a technological demonstrator is being assembled to validate the full instrument design and to test it electrically, thermally and optically. The technical demonstrator is a scaled-down version of Module 1 in terms of the number of detectors, input horns and pulse tubes and a reduction in the diameter of the combiner mirrors and filters, but is otherwise similar. The demonstrator will be upgraded to the full module in 2019. In this paper we give an overview of the QUBIC project and instrument.

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Additional Information:© 2018 Society of Photo-optical Instrumentation Engineers (SPIE). INFN in Italy and IN2P3/CNRS in France are thanked for their funding of the QUBIC project. D. Burke and J.D. Murphy acknowledge funding from the Irish Research Council under the Government of Ireland Postgraduate Scholarship scheme. M. De Leo thanks the Astrophysics Group at the University of Surrey for allowing his continued participation in the QUBIC Collaboration.
Funding AgencyGrant Number
Istituto Nazionale di Fisica Nucleare (INFN)UNSPECIFIED
Institut National de Physique Nucléaire et de Physique des Particules (IN2P3)UNSPECIFIED
Centre National de la Recherche Scientifique (CNRS)UNSPECIFIED
Irish Research CouncilUNSPECIFIED
Subject Keywords:CMB, B-modes, bolometric interferometry, QUBIC
Series Name:Proceedings of SPIE
Issue or Number:10708
Record Number:CaltechAUTHORS:20190108-155925412
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Official Citation:C. O'Sullivan, P. Ade, G. Amico, D. Auguste, J. Aumont, S. Banfi, G. Barbarán, P. Battaglia, E. Battistelli, A. Baù, B. Bélier, D. Bennett, L. Bergé, J.-Ph. Bernard, M. Bersanelli, M.-A. Bigot-Sazy, N. Bleurvacq, J. Bonaparte, J. Bonis, G. Bordier, E. Bréelle, E. Bunn, D. Burke, D. Buzi, A. Buzzelli, F. Cavaliere, P. Chanial, C. Chapron, R. Charlassier, F. Columbro, G. Coppi, A. Coppolecchia, F. Couchot, R. D'Agostino, G. D’Alessandro, P. de Bernardis, G. de Gasperis, M. De Leo, M. De Petris, A. Di Donato, L. Dumoulin, A. Etchegoyen, A. Fasciszewski, C. Franceschet, M. M. Gamboa Lerena, B. García, X. Garrido, M. Gaspard, A. Gault, D. Gayer, M. Gervasi, M. Giard, Y. Giraud-Héraud, M. Gómez Berisso, M. González, M. Gradziel, L. Grandsire, E. Guerrard, J.-Ch. Hamilton, D. Harari, V. Haynes, S. Henrot-Versillé, D. T. Hoang, F. Incardona, E. Jules, J. Kaplan, A. Korotkov, C. Kristukat, L. Lamagna, S. Loucatos, T. Louis, A. Lowitz, V. Lukovic, R. Luterstein, B. Maffei, S. Marnieros, S. Masi, A. Mattei, A. May, M. McCulloch, M. C. Medina, L. Mele, S. Melhuish, A. Mennella, L. Montier, L. M. Mundo, J. A. Murphy, J. D. Murphy, E. Olivieri, A. Paiella, F. Pajot, A. Passerini, H. Pastoriza, A. Pelosi, C. Perbost, O. Perdereau, F. Pezzotta, F. Piacentini, M. Piat, L. Piccirillo, G. Pisano, G. Polenta, D. Prêle, R. Puddu, D. Rambaud, P. Ringegni, G. E. Romero, M. Salatino, A. Schillaci, C. G. Scóccola, S. Scully, S. Spinelli, M. Stolpovskiy, F. Suarez, A. Tartari, J.-P. Thermeau, P. Timbie, S. A. Torchinsky, M. Tristram, V. Truongcanh, C. Tucker, G. Tucker, S. Vanneste, D. Viganò, N. Vittorio, F. Voisin, B. Watson, F. Wicek, M. Zannoni, A. Zullo, "QUBIC: the Q and U bolometric interferometer for cosmology," Proc. SPIE 10708, Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy IX, 107082B (9 July 2018); doi: 10.1117/12.2313332
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:92149
Deposited By: Tony Diaz
Deposited On:09 Jan 2019 00:13
Last Modified:03 Oct 2019 20:41

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