43 research outputs found
QUBIC: The QU Bolometric Interferometer for Cosmology
One of the major challenges of modern cosmology is the detection of B-mode
polarization anisotropies in the CMB. These originate from tensor fluctuations
of the metric produced during the inflationary phase. Their detection would
therefore constitute a major step towards understanding the primordial
Universe. The expected level of these anisotropies is however so small that it
requires a new generation of instruments with high sensitivity and extremely
good control of systematic effects. We propose the QUBIC instrument based on
the novel concept of bolometric interferometry, bringing together the
sensitivity advantages of bolometric detectors with the systematics effects
advantages of interferometry. Methods: The instrument will directly observe the
sky through an array of entry horns whose signals will be combined together
using an optical combiner. The whole set-up is located inside a cryostat.
Polarization modulation will be achieved using a rotating half-wave plate and
interference fringes will be imaged on two focal planes (separated by a
polarizing grid) tiled with bolometers. We show that QUBIC can be considered as
a synthetic imager, exactly similar to a usual imager but with a synthesized
beam formed by the array of entry horns. Scanning the sky provides an
additional modulation of the signal and improve the sky coverage shape. The
usual techniques of map-making and power spectrum estimation can then be
applied. We show that the sensitivity of such an instrument is comparable with
that of an imager with the same number of horns. We anticipate a low level of
beam-related systematics thanks to the fact that the synthesized beam is
determined by the location of the primary horns. Other systematics should be
under good control thanks to an autocalibration technique, specific to our
concept, that will permit the accurate determination of most of the systematics
parameters.Comment: 12 pages, 10 figures, submitted to Astronomy and Astrophysic
QUBIC: The Q&U Bolometric Interferometer for Cosmology - A novel way to look at the polarized Cosmic Microwave Background
In this paper we describe QUBIC, an experiment that takes up the challenge posed by the detection of primordial gravitational waves with a novel approach, that combines the sensitivity of state-of-the art bolometric detectors with the systematic effects control typical of interferometers. The so-called "self-calibration" is a technique deeply rooted in the interferometric nature of the instrument and allows us to clean the measured data from instrumental effects. The first module of QUBIC is a dual band instrument (150 GHz and 220 GHz) that will be deployed in Argentina during the Fall 2018.Fil: Mennella, Aniello. University of Milan; ItaliaFil: Ade, P. A. R.. Cardiff University; Reino UnidoFil: Aumont, J.. Institut d'Astrophysique Spatiale; FranciaFil: Banfie, S.. Istituto Nazionale Di Fisica Nucleare; ItaliaFil: Battaglia, P.. Università degli Studi di Trieste; ItaliaFil: Battistelli, E. S.. Università degli Studi di Roma "La Sapienza"; ItaliaFil: Baùe, F.. Istituto Nazionale Di Fisica Nucleare; ItaliaFil: Buzi, D.. Università degli Studi di Roma "La Sapienza"; ItaliaFil: Columbro, F.. Università degli Studi di Roma "La Sapienza"; ItaliaFil: Bélie, B.. Institute of Fundamental Electronics; FranciaFil: Bennett, D.. Maynooth University; IrlandaFil: Bergé, L.. Centre de Sciences Nucléaires et de Sciences de la Matière; FranciaFil: Bernard, J. Ph.. Institut de Recherche en Astrophysique et Planétologie; FranciaFil: Bersanelli, M.. University of Milan; ItaliaFil: Bigot Sazy, M. A.. APC; FranciaFil: Bleurvacq, N.. APC; FranciaFil: Bordier, G.. APC; FranciaFil: Brossard, J.. APC; FranciaFil: Bunn, E. F.. Richmond University; Estados UnidosFil: Burke, D. P.. Maynooth University; IrlandaFil: Buzi, D.. Università degli Studi di Roma "La Sapienza"; ItaliaFil: Buzzelli, A.. Universita Tor Vergata; ItaliaFil: Cammilleri, D.. APC; FranciaFil: Cavaliere, F.. University of Milan; ItaliaFil: Chanial, P.. APC; FranciaFil: Etchegoyen, Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Tecnología en Detección y Astropartículas. Comisión Nacional de Energía Atómica. Instituto de Tecnología en Detección y Astropartículas. Universidad Nacional de San Martín. Instituto de Tecnología en Detección y Astropartículas; ArgentinaFil: Harari, Diego Dario. Comisión Nacional de Energía Atómica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Medina, Maria Clementina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Romero, Gustavo Esteban. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Suarez, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Tecnología en Detección y Astropartículas. Comisión Nacional de Energía Atómica. Instituto de Tecnología en Detección y Astropartículas. Universidad Nacional de San Martín. Instituto de Tecnología en Detección y Astropartículas; ArgentinaThe European Physical Society Conference on High Energy PhysicsVeneciaItaliaEuropean Physical Societ
Activité biologique du 25-hydroxycholécalciférol dans les ostéomalacies vitamino-résistantes
Les métabolites de la vitamine D : leur action sur l'os des rats carencés en vitamine D
International audienc