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Simulations and performance of the QUBIC optical beam combiner

O'Sullivan, C. and Schillaci, A. (2018) Simulations and performance of the QUBIC optical beam combiner. 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. 107082I. ISBN 9781510619692.

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QUBIC, the Q & U Bolometric Interferometer for Cosmology, is a novel ground-based instrument that aims 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 immunity to systematic effects of an interferometer. It will directly observe the sky through an array of back-to-back entry horns whose beams will be superimposed using a cooled quasioptical beam combiner. Images of the resulting interference fringes will be formed on two focal planes, each tiled with transition-edge sensors, cooled down to 320 mK. A dichroic filter placed between the optical combiner and the focal planes will select two frequency bands (centred at 150 GHz and 220 GHz), one frequency per focal plane. Polarization modulation will be achieved using a cold stepped half-wave plate (HWP) and polariser in front of the sky-facing horns. The full QUBIC instrument is described elsewhere; in this paper we will concentrate in particular on simulations of the optical combiner (an off-axis Gregorian imager) and the feedhorn array. We model the optical performance of both the QUBIC full module and a scaled-down technological demonstrator which will be used to validate the full instrument design. Optical modelling is carried out using full vector physical optics with a combination of commercial and in-house software. In the high-frequency channel we must be careful to consider the higher-order modes that can be transmitted by the horn array. The instrument window function is used as a measure of performance and we investigate the effect of, for example, alignment and manufacturing tolerances, truncation by optical components and off-axis aberrations. We also report on laboratory tests carried on the QUBIC technological demonstrator in advance of deployment to the observing site in Argentina.

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Additional Information:© 2018 Society of Photo-optical Instrumentation Engineers (SPIE). 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. The APC team acknowledges the financial support of the UnivEarthS Labex program at Sorbonne Paris Cité (ANR-10-LABX-0023 and ANR-11-IDEX-0005-02). INFN in Italy and CNRS/IN2P3 in France are thanked for their funding of the QUBIC project.
Funding AgencyGrant Number
Irish Research CouncilUNSPECIFIED
Agence Nationale pour la Recherche (ANR)ANR-10-LABX-0023
Agence Nationale pour la Recherche (ANR)ANR-11-IDEX-0005-02
Istituto Nazionale di Fisica Nucleare (INFN)UNSPECIFIED
Centre National de la Recherche Scientifique (CNRS)UNSPECIFIED
Institut National de Physique Nucléaire et de Physique des Particules (IN2P3)UNSPECIFIED
Subject Keywords:CMB, B-modes, bolometric interferometry, QUBIC, physical optics
Series Name:Proceedings of SPIE
Issue or Number:10708
Record Number:CaltechAUTHORS:20190108-150941604
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Official Citation:C. O'Sullivan, D. Burke, D. Gayer, J. D. Murphy, S. Scully, M. De Leo, M. De Petris, A. Mattei, A. Zullo, A. Mennella, M. Zannoni, N. Bleurvacq, C. Chapron, J.-Ch. Hamilton, M. Piat, 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, J. Bonaparte, J. Bonis, G. Bordier, E. Bréelle, E. Bunn, D. Buzi, A. Buzzelli, F. Cavaliere, P. Chanial, R. Charlassier, F. Columbro, G. Coppi, A. Coppolecchia, F. Couchot, R. D'Agostino, G. D’Alessandro, P. de Bernardis, G. De Gasperis, A. Di Donato, L. Dumoulin, A. Etchegoyen, A. Fasciszewski, C. Franceschet, M. M. Gamboa Lerena, B. García, X. Garrido, M. Gaspard, A. Gault, M. Gervasi, M. Giard, Y. Giraud-Héraud, M. Gómez Berisso, M. González, M. Gradziel, L. Grandsire, E. Guerrard, 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. May, M. McCulloch, M. C. Medina, L. Mele, S. Melhuish, L. Montier, L. M. Mundo, J. A. Murphy, E. Olivieri, A. Paiella, F. Pajot, A. Passerini, H. Pastoriza, A. Pelosi, C. Perbost, O. Perdereau, F. Pezzotta, F. Piacentini, 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. 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, "Simulations and performance of the QUBIC optical beam combiner," Proc. SPIE 10708, Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy IX, 107082I (9 July 2018); doi: 10.1117/12.2313256
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:92147
Deposited By: Tony Diaz
Deposited On:08 Jan 2019 23:30
Last Modified:03 Oct 2019 20:41

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