QUBIC I: Overview and science program Mousset, L.; Battistelli, E.S.; de Bernardis, P. ...
Journal of Cosmology and Astroparticle Physics,
04/2022, Letnik:
2022, Številka:
4
Journal Article
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Abstract
The Q & U Bolometric Interferometer for Cosmology (QUBIC) is a novel kind of polarimeter optimized for the measurement of the B-mode polarization of the Cosmic Microwave Background (CMB), ...which is one of the major challenges of observational cosmology. The signal is expected to be of the order of a few tens of nK, prone to instrumental systematic effects and polluted by various astrophysical foregrounds which can only be controlled through multichroic observations. QUBIC is designed to address these observational issues with a novel approach that combines the advantages of interferometry in terms of control of instrumental systematic effects with those of bolometric detectors in terms of wide-band, background-limited sensitivity. The QUBIC synthesized beam has a frequency-dependent shape that results in the ability to produce maps of the CMB polarization in multiple sub-bands within the two physical bands of the instrument (150 and 220 GHz). These features make QUBIC complementary to other instruments and makes it particularly well suited to characterize and remove Galactic foreground contamination. In this article, first of a series of eight, we give an overview of the QUBIC instrument design, the main results of the calibration campaign, and present the scientific program of QUBIC including not only the measurement of primordial B-modes, but also the measurement of Galactic foregrounds.
We give forecasts for typical observations and measurements: with three years of integration on the sky and assuming perfect foreground removal as well as stable atmospheric conditions from our site in Argentina, our simulations show that we can achieve a statistical sensitivity to the effective tensor-to-scalar ratio (including primordial and foreground B-modes)
σ
(
r
)=0.015.
A novel system formed by a Microwave Superconducting Quantum Interference Device (SQUID) Multiplexer (
μ
MUX) and a room temperature electronics employs frequency division multiplexing (FDM) ...technique to read out multiple cryogenic detectors. Since the detector signal is embedded in the phase of the SQUID signal, a Digital Quadrature Demodulator (DQD) is widely implemented to recover it. However, the DQD also generates a signal that aliases into the first Nyquist zone affecting the demodulated detector signal. In this work, we demonstrate how this spurious signal is generated and a mathematical model of it is derived and validated. In addition, we discuss different proposals to improve the attenuation of this undesired signal. Lastly, we implement one of the proposals in our readout system. Our measurements show an enhancement in the spurious signal attenuation of more than 35 dB. As a result, this work contributes to attenuate the spurious below the system noise.
We describe a technique to optimize the dynamic performance of microwave SQUID multiplexer (µMUX)-based systems. These systems proved to be adequate for reading out multiple cryogenic detectors ...simultaneously. However, the requirement for denser detector arrays to increase the sensitivity of scientific experiments makes its design a challenge. When modifying the readout power, there is a trade-off between decreasing the signal-to-noise ratio (SNR) and boosting the nonlinearities of the active devices. The latter is characterized by the spurious free dynamic range (SFDR) parameter and manifests as an increment in the intermodulation products and harmonics power. We estimate the optimal spectral location of the SQUID signal containing the detector information for different channels. Through the technique, what we refer to as
Spectral Engineering
, it is possible to minimize the SNR degradation while maximizing the SFDR of the detector signal, thus, overcoming the trade-off.
This work reports the performance evaluation of an SDR readout system based on the latest generation (Gen3) of AMD’s Radio-Frequency System-on-Chip (RFSoC) processing platform, which integrates a ...full-stack processing system and a powerful FPGA with up to 32 high-speed and high-resolution 14-bit Digital-to-Analog Converters and 14-bit Analog-to-Digital Converters. The proposed readout system uses a previously developed multi-band, double-conversion IQ RF-mixing board targeting a multiplexing factor of approximately 1000 bolometers in a bandwidth between 4 and 8 GHz, in line with state-of-the-art microwave SQUID multiplexers. The characterization of the system was performed in two stages, under the conditions typically imposed by the multiplexer and the cold readout circuit: first, in transmission, showing that noise and spurious levels of the generated tones are close to the values imposed by the cold readout, and second, in RF loopback, presenting noise values better than −100 dBc/Hz totally in agreement with the state-of-the-art readout systems. It was demonstrated that the RFSoC Gen3 device is a suitable enabling technology for the next generation of superconducting detector readout systems, reducing system complexity, increasing system integration, and achieving these goals without performance degradation.
Abstract
In this work we present an application of the Goertzel
Filter for the channelization of multi-tonal signals, typically used
for the read-out of cryogenic sensors which are multiplexed in the
...frequency domain (FDM), by means of Microwave Superconducting
Quantum Interference Device (SQUID) Multiplexer (μMUX). We
demonstrate how implementing a bank of many of these filters, can be
used to perform a channelization of the multi-tonal input signal to
retrieve the data added by the sensors. We show how this approach
can be implemented in a resource-efficient manner in a Field
Programmable Gate Array (FPGA) within the state-of-the-art, which
allows great scalability for reading thousands of sensors; as is
required by Radio Telescopes in Cosmic Microwave Background
Radiation (CMB) surveys using cryogenic bolometers, particles
detection like Neutrino mass estimation using cryogenic calorimeters
or Quantum Computing.
The Q&U Bolometric Interferometer for Cosmology (QL’BIC) is the first bolometric interferometer designed to measure the primordial B-mode polarization of the Cosmic Microwave Background (CMB). ...Bolometric interferometry is a novel technique that combines the sensitivity of bolometric detectors with the control of systematic effects that is typical of interferometry, both key features in the quest for the faint signal of the primordial B-modes. A unique feature is the so-called “spectral imaging”, i.e., the ability to recover the sky signal in several sub-bands within the physical band during data analysis. This feature provides an in-band spectral resolution of ∆v/v ~ 0.04 that is unattainable by a traditional imager. This is a key tool for controlling the Galactic foregrounds contamination. In this paper, we describe the principles of bolometric interferometry, the current status of the QU BIC experiment and future prospects.
Modulated HF heating of the auroral electrojet is used to inject ELF signals into the magnetosphere that are observed on the low altitude DEMETER spacecraft. The HF heater is a component of the ...High‐Frequency Active Auroral Research Program (HAARP) facility in Gakona, Alaska, (located at L ∼ 4.9). Simultaneous observations of all six components of the ELF electromagnetic fields on the DEMETER spacecraft are used to estimate the total ELF power radiated downward into the Earth‐ionosphere waveguide. ELF signals generated by the HAARP heater are also simultaneously observed at a nearby ground‐based site, allowing a comparison of the ELF power in the Earth‐ionosphere waveguide versus that detected on DEMETER. The estimated values of power onboard DEMETER at different frequencies range from 0.32W to 4W, while the values of power estimated from a ground receiver at a distance of 36 km from HAARP range from 2.71W to 4.22W.
We report a measurement of the energy spectrum of cosmic rays for energies above 2.5 × 1018 eV based on 215,030 events recorded with zenith angles below 60°. A key feature of the work is that the ...estimates of the energies are independent of assumptions about the unknown hadronic physics or of the primary mass composition. The measurement is the most precise made hitherto with the accumulated exposure being so large that the measurements of the flux are dominated by systematic uncertainties except at energies above 5 × 1019 eV. The principal conclusions are (1) The flattening of the spectrum near 5 × 1018 eV, the so-called "ankle," is confirmed. (2) The steepening of the spectrum at around 5 × 1019 eV is confirmed. (3) A new feature has been identified in the spectrum: in the region above the ankle the spectral index γ of the particle flux ( ∝ E−γ ) changes from 2.51 ± 0.03 ( stat ) ± 0.05 ( syst ) to 3.05 ± 0.05 ( stat ) ± 0.10 ( syst ) before changing sharply to 5.1 ± 0.3 ( stat ) ± 0.1 ( syst ) above 5 × 1019 eV. (4) No evidence for any dependence of the spectrum on declination has been found other than a mild excess from the Southern Hemisphere that is consistent with the anisotropy observed above 8 × 1018 eV.
The Pierre Auger Cosmic Ray Observatory Aab, A.; Abreu, P.; Aglietta, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2015, Letnik:
798, Številka:
C
Journal Article
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The Pierre Auger Observatory, located on a vast, high plain in western Argentina, is the world׳s largest cosmic ray observatory. The objectives of the Observatory are to probe the origin and ...characteristics of cosmic rays above 1017eV and to study the interactions of these, the most energetic particles observed in nature. The Auger design features an array of 1660 water Cherenkov particle detector stations spread over 3000km2 overlooked by 24 air fluorescence telescopes. In addition, three high elevation fluorescence telescopes overlook a 23.5km2, 61-detector infilled array with 750m spacing. The Observatory has been in successful operation since completion in 2008 and has recorded data from an exposure exceeding 40,000km2sryr. This paper describes the design and performance of the detectors, related subsystems and infrastructure that make up the Observatory.
The first simultaneous measurements of discrete chorus emissions on multiple spacecraft, realized in the context of the Cluster mission, revealed a rather unexpected frequency difference of around 1 ...kHz between nearly identical discrete elements observed on different spacecraft Gurnett et al., 2001. This frequency difference is interpreted herein as a natural outcome of the dependence of the whistler‐mode refractive index on the wave normal angle between the wave vector k and the static magnetic field B0 and the rapid motion of highly localized source region(s) of chorus of 400 km to 1700 km in extent along the field line, but only less than 100 km transverse to the magnetic field, and moving at speeds of 20,000 km/s to 25,000 km/s. Wave packets emanating from the localized regions propagate to two spacecraft at different wave normal angles, and are observed at different frequencies due to the differential Doppler shift between the two spacecraft. These differences in frequency, as well as the different times of arrival of the similar emissions at the different spacecraft, provide a unique opportunity to estimate the source characteristics, using a model involving rapidly moving sources traveling at speeds comparable to the parallel resonant velocity of counterstreaming electrons moving along the Earth's magnetic field lines. We report the determination of chorus emission source region motion for two different cases observed during 2000–2001, where these differences in frequency were readily observable due to the relatively large separation of the Cluster spacecraft. We also report a case in 2002 where the spacecraft separations were smaller, so that these frequency differences were not as evident but nevertheless measurable. In general, our results provide the first experimental evidence that the sources that generate the discrete chorus emissions are in rapid motion.
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