10 research outputs found
HI intensity mapping with FAST
We discuss the detectability of large-scale HI intensity fluctuations using
the FAST telescope. We present forecasts for the accuracy of measuring the
Baryonic Acoustic Oscillations and constraining the properties of dark energy.
The FAST -beam L-band receivers (-- GHz) can provide
constraints on the matter power spectrum and dark energy equation of state
parameters () that are comparable to the BINGO and CHIME
experiments. For one year of integration time we find that the optimal survey
area is . However, observing with larger frequency coverage
at higher redshift (-- GHz) improves the projected errorbars on the
HI power spectrum by more than confidence level. The combined
constraints from FAST, CHIME, BINGO and Planck CMB observations can provide
reliable, stringent constraints on the dark energy equation of state.Comment: 7 pages, 3 figures, submitted to "Frontiers in Radio Astronomy and
FAST Early Sciences Symposium 2015" conference proceedin
Detection chain and electronic readout of the QUBIC instrument
The Q and U Bolometric Interferometer for Cosmology (QUBIC) Technical Demonstrator (TD) aiming to shows the feasibility of the combination of interferometry and bolometric detection. The electronic readout system is based on an array of 128 NbSi Transition Edge Sensors cooled at 350mK readout with 128 SQUIDs at 1K controlled and amplified by an Application Specific Integrated Circuit at 40K. This readout design allows a 128:1 Time Domain Multiplexing. We report the design and the performance of the detection chain in this paper. The technological demonstrator unwent a campaign of test in the lab. Evaluation of the QUBIC bolometers and readout electronics includes the measurement of I-V curves, time constant and the Noise Equivalent Power. Currently the mean Noise Equivalent Power is ~ 2 x 10â»ÂčⶠW/âHz
Detection chain and electronic readout of the QUBIC instrument
The Q and U Bolometric Interferometer for Cosmology (QUBIC) Technical Demonstrator (TD) aiming to shows the feasibility of the combination of interferometry and bolometric detection. The electronic readout system is based on an array of 128 NbSi Transition Edge Sensors cooled at 350mK readout with 128 SQUIDs at 1K controlled and amplified by an Application Specific Integrated Circuit at 40K. This readout design allows a 128:1 Time Domain Multiplexing. We report the design and the performance of the detection chain in this paper. The technological demonstrator unwent a campaign of test in the lab. Evaluation of the QUBIC bolometers and readout electronics includes the measurement of I-V curves, time constant and the Noise Equivalent Power. Currently the mean Noise Equivalent Power is ~ 2 x 10â»ÂčⶠW/âHz
Mesure des anisotropies de polarisation du fond diffus cosmologique avec l'interféromÚtre bolométrique QUBIC
The quest of B-mode polarisation of the cosmic background is one of the scientific priorities of the observational cosmology today. Observing the B-mode would be the most direct way to constrain the period of inflation. The detection of such a weak signal is however a real experimental challenge. In addition to a high statistical sensitivity (huge number of horns and bolometers required), future experiments will need an excellent quality of foreground removal and an unprecedented control of systematics. An important experimental effort aiming at the detection of the B-mode is in progress. The QUBIC instrument is one of the many experiments dedicated to the search of B-mode, it is based on a novel technology: bolometric interferometry. In this thesis, we explain the design of this instrument and we describe the different components. We will focus on the optical beam combiner, we will present a method which allows to study the effects of optical aberrations and of misalignments of the components of the combiner on the global sensitivity of the instrument. We will develop a new specific procedure of calibration: the self-calibration, specific to bolometric interferometry, which is based on the redundancy of baselines. The self-calibration relies on comparing all the redundant baselines with each others and permits to calibrate parameters that characterize completely the instrument at the same time for each channel. Finally, we will present the latest results of the simulation for the map-making with the instrument QUBIC and the estimation of the power spectra from the resulting maps.La quĂȘte des modes B de polarisation du fond diffus cosmologique est aujourd'hui un des enjeux scientifiques majeurs de la cosmologie observationnelle. Observer les modes B constituerait une sonde directe de la pĂ©riode d'inflation. La dĂ©tection de ce signal, attendu Ă un niveau trĂšs faible, reprĂ©sente un dĂ©fi technologique. Il nĂ©cessite non seulement une sensibilitĂ© importante, mais aussi une soustraction des signaux d'avant-plans et un trĂšs bon contrĂŽle des effets systĂ©matiques. Dans ce but, un important travail expĂ©rimental est en cours. L'instrument QUBIC est une des expĂ©riences dĂ©diĂ©es Ă la dĂ©tection des modes B. Il est basĂ© sur une technologie novatrice : l'interfĂ©romĂ©trie bolomĂ©trique, qui permet de rĂ©unir les avantages d'un imageur en terme de sensibilitĂ© et ceux d'un interfĂ©romĂštre en terme de contrĂŽle des effets systĂ©matiques. Dans ce manuscrit, nous expliquerons le concept de l'instrument et nous dĂ©crirons ses composantes. Nous nous concentrerons sur le combineur optique de l'instrument dont nous expliciterons le rĂŽle et nous prĂ©senterons une mĂ©thode dĂ©veloppĂ©e afin d'Ă©tudier l'impact des aberrations optiques et des dĂ©salignements des composantes du combineur sur la sensibilitĂ© globale de l'instrument. Nous introduirons une procĂ©dure de calibration spĂ©cifique Ă l'interfĂ©romĂ©trie bolomĂ©trique basĂ©e sur la redondance des lignes de base : la self-calibration. Cette mĂ©thode permet de calibrer les paramĂštres qui caractĂ©risent complĂštement l'instrument simultanĂ©ment et pour chaque canal cornet-bolomĂštre-pointage. Finalement, nous prĂ©senterons les derniĂšres avancĂ©es des simulations sur la fabrication des cartes avec l'instrument QUBIC et sur l'estimation des spectres de puissance
QUBIC-the Q & U bolometric interferometer for cosmology
QUBIC (Q and U bolometric interferometer for cosmology) is an international ground-based experiment dedicated to the measurement of the polarized fluctuations of the cosmic microwave background (CMB). It is based on bolometric interferometry, an original detection technique which combines the immunity to systematic effects of an interferometer with the sensitivity of low temperature incoherent detectors. QUBIC will be deployed in Argentina, at the Alto Chorrillos mountain site near San Antonio de los Cobres, in the Salta province. The QUBIC detection chain consists of 2048 NbSi transition edge sensors (TESs) cooled to 320 mK. The voltage-biased TESs are read out with time domain multiplexing based on superconducting quantum interference devices (SQUIDs) at 1 K and a novel SiGe application-specific integrated circuit (ASIC) at 60 K allowing an unprecedented multiplexing (MUX) factor equal to 128 to be reached. The current QUBIC version is based on a reduced number of detectors (1/4) in order to validate the detection technique. The QUBIC experiment is currently being validated in the lab in Salta (Argentina) before going to the site for observations. This paper presents the main results of the characterization phase with a focus on the detectors and readout system
Thermal architecture for the QUBIC cryogenic receiver
QUBIC, the QU Bolometric Interferometer for Cosmology, is a novel forthcoming instrument to measure the B-mode polarization anisotropy of the Cosmic Microwave Background. The detection of the B-mode signal will be extremely challenging; QUBIC has been designed to address this with a novel approach, namely bolometric interferometry. The receiver cryostat is exceptionally large and cools complex optical and detector stages to 40 K, 4 K, 1 K and 350 mK using two pulse tube coolers, a novel 4He sorption cooler and a double-stage 3He/4He sorption cooler. We discuss the thermal and mechanical design of the cryostat, modelling and thermal analysis, and laboratory cryogenic testing
Simulations and performance of the QUBIC optical beam combiner
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 o
Performance of NbSi transition-edge sensors readout with a 128 MUX factor for the QUBIC experiment
QUBIC (the Q and U Bolometric Interferometer for Cosmology) is a ground-based experiment which seeks to improve the current constraints on the amplitude of primordial gravitational waves. It exploits the unique technique, among Cosmic Microwave Background experiments, of bolometric interferometry, combining together the sensitivity of bolometric detectors with the control of systematic effects typical of interferometers. QUBIC will perform sky observations in polarization, in two frequency bands centered at 150 and 220 GHz, with two kilo-pixel focal plane arrays of NbSi Transition-Edge Sensors (TES) cooled down to 350 mK. A subset of the QUBIC instrument, the so called QUBIC Technological Demonstrator (TD), with a reduced number of detectors with respect to the full instrument, will be deployed and commissioned before the end of 2018.
The voltage-biased TES are read out with Time Domain Multiplexing and an unprecedented multiplexing (MUX) factor equal to 128. This MUX factor is reached with two-stage multiplexing: a traditional one exploiting Superconducting QUantum Interference Devices (SQUIDs) at 1K and a novel SiGe Application-Specific Integrated Circuit (ASIC) at 60 K. The former provides a MUX factor of 32, while the latter provides a further 4. Each TES array is composed of 256 detectors and read out with four modules of 32 SQUIDs and two ASICs. A custom software synchronizes and manages the readout and detector operation, while the TES are sampled at 780 Hz (100kHz/128 MUX rate).
In this work we present the experimental characterization of the QUBIC TES arrays and their multiplexing readout chain, including time constant, critical temperature, and noise properties
QUBIC:Exploring the primordial universe with the Q&U bolometric interferometer
In this paper we describe QUBIC, an experiment that will observe the
polarized microwave sky with a novel approach, which combines the sensitivity
of state-of-the art bolometric detectors with the systematic effects control
typical of interferometers. QUBIC unique features are the so-called
"self-calibration", a technique that allows us to clean the measured data from
instrumental effects, and its spectral imaging power, i.e. the ability to
separate the signal in various sub-bands within each frequency band. QUBIC will
observe the sky in two main frequency bands: 150 GHz and 220 GHz. A
technological demonstrator is currently under testing and will be deployed in
Argentina during 2019, while the final instrument is expected to be installed
during 2020.Comment: Proceedings of the 2018 ICNFP conference, Crete. Published by
Universe arXiv admin note: text overlap with arXiv:1801.0373
QUBIC: the Q and U bolometric interferometer for cosmology
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 o