LiteBIRD, the next-generation cosmic microwave background (CMB) experiment, aims for a launch in Japan’s fiscal year 2032, marking a major advancement in the exploration of primordial cosmology and fundamental physics. Orbiting the Sun-Earth Lagrangian point L2, this JAXA-led strategic L-class mission will conduct a comprehensive mapping of the CMB polarization across the entire sky. During its 3-year mission, LiteBIRD will employ three telescopes within 15 unique frequency bands (ranging from 34 through 448 GHz), targeting a sensitivity of 2.2 μK-arcmin and a resolution of 0.5° at 100 GHz. Its primary goal is to measure the tensor-toscalar ratio r with an uncertainty δr = 0.001, including systematic errors and margin. If r ≥ 0.01, LiteBIRD expects to achieve a > 5σ detection in the ℓ = 2–10 and ℓ = 11–200 ranges separately, providing crucial insight into the early Universe. We describe LiteBIRD’s scientific objectives, the application of systems engineering to mission requirements, the anticipated scientific impact, and the operations and scanning strategies vital to minimizing systematic effects. We will also highlight LiteBIRD’s synergies with concurrent CMB projects.
LiteBIRD is a next-generation space telescope which aims to measure primordial gravitational waves in the polarisation of the cosmic microwave background. The level of the primordial (tensor, or B-mode) signal in relation to the scalar (or E-mode) only has a known upper limit, and the instrument requirement is to measure a tensor-to-scalar ratio sensitivity δr<0.001. Systematic effects arising from cosmic radiation are expected to play a significant role, and our prior work has focused on the development of an end-to-end simulation tool for evaluating the scale of this in LiteBIRD’s Low Frequency Telescope (LFT). We present an updated forecasting method which makes use of event tables generated by a new Geant4 mass model of LFT. We will compare the previously used simplified model with that of the updated mass model, and project these differences into an expected effect of the cosmic ray effect δr. Lastly, we will examine the use of a simple filtering method for removing direct detector impacts by cosmic rays, which have been shown previously to play the largest role in this systematic effect.
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.
LiteBIRD, the Lite (Light) satellite for the study of B-mode polarization and Inflation from cosmic background Radiation Detection, is a space mission for primordial cosmology and fundamental physics. JAXA selected LiteBIRD in May 2019 as a strategic large-class (L-class) mission, with its expected launch in the late 2020s using JAXA's H3 rocket. LiteBIRD plans to map the cosmic microwave background (CMB) polarization over the full sky with unprecedented precision. Its main scientific objective is to carry out a definitive search for the signal from cosmic inflation, either making a discovery or ruling out well-motivated inflationary models. The measurements of LiteBIRD will also provide us with an insight into the quantum nature of gravity and other new physics beyond the standard models of particle physics and cosmology. To this end, LiteBIRD will perform full-sky surveys for three years at the Sun-Earth Lagrangian point L2 for 15 frequency bands between 34 and 448 GHz with three telescopes, to achieve a total sensitivity of 2.16 μK-arcmin with a typical angular resolution of 0.5° at 100 GHz. We provide an overview of the LiteBIRD project, including scientific objectives, mission requirements, top-level system requirements, operation concept, and expected scientific outcomes.
LiteBIRD has been selected as JAXA’s strategic large mission in the 2020s, to observe the cosmic microwave background (CMB) B-mode polarization over the full sky at large angular scales. The challenges of LiteBIRD are the wide field-of-view (FoV) and broadband capabilities of millimeter-wave polarization measurements, which are derived from the system requirements. The possible paths of stray light increase with a wider FoV and the far sidelobe knowledge of -56 dB is a challenging optical requirement. A crossed-Dragone configuration was chosen for the low frequency telescope (LFT : 34–161 GHz), one of LiteBIRD’s onboard telescopes. It has a wide field-of-view (18° x 9°) with an aperture of 400 mm in diameter, corresponding to an angular resolution of about 30 arcminutes around 100 GHz. The focal ratio f/3.0 and the crossing angle of the optical axes of 90◦ are chosen after an extensive study of the stray light. The primary and secondary reflectors have rectangular shapes with serrations to reduce the diffraction pattern from the edges of the mirrors. The reflectors and structure are made of aluminum to proportionally contract from warm down to the operating temperature at 5 K. A 1/4 scaled model of the LFT has been developed to validate the wide field-of-view design and to demonstrate the reduced far sidelobes. A polarization modulation unit (PMU), realized with a half-wave plate (HWP) is placed in front of the aperture stop, the entrance pupil of this system. A large focal plane with approximately 1000 AlMn TES detectors and frequency multiplexing SQUID amplifiers is cooled to 100 mK. The lens and sinuous antennas have broadband capability. Performance specifications of the LFT and an outline of the proposed verification plan are presented.
LiteBIRD is a JAXA-led Strategic Large-Class mission designed to search for the existence of the primordial gravitational waves produced during the inflationary phase of the Universe, through the measurements of their imprint onto the polarization of the cosmic microwave background (CMB). These measurements, requiring unprecedented sensitivity, will be performed over the full sky, at large angular scales, and over 15 frequency bands from 34 GHz to 448 GHz. The LiteBIRD instruments consist of three telescopes, namely the Low-, Medium-and High-Frequency Telescope (respectively LFT, MFT and HFT). We present in this paper an overview of the design of the Medium-Frequency Telescope (89{224 GHz) and the High-Frequency Telescope (166{448 GHz), the so-called MHFT, under European responsibility, which are two cryogenic refractive telescopes cooled down to 5 K. They include a continuous rotating half-wave plate as the first optical element, two high-density polyethylene (HDPE) lenses and more than three thousand transition-edge sensor (TES) detectors cooled to 100 mK. We provide an overview of the concept design and the remaining specific challenges that we have to face in order to achieve the scientific goals of LiteBIRD.
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 10-16W= p √Hz
QUBIC (a Q and U Bolometric Interferometer for Cosmology) is a next generation cosmology experiment designed to detect the B-mode polarisation of the Cosmic Microwave Background (CMB). A B-mode detection is hard evidence of Inflation in the ΛCDM model. QUBIC aims to accomplish this by combining novel technologies to achieve the sensitivity required to detect the faint B-mode signal. QUBIC uses technologies such as a rotating half-wave plate, cryogenics, interferometric horns with self-calibration switches and transition edge sensor bolometers. A Technical Demonstrator (TD) is currently being calibrated in APC in Paris before observations in Argentina in 2021. As part of the calibration campaign, the spectral response of the TD is measured to test and validate QUBIC's spectro-imaging capability. This poster gives an overview of the methods used to measure the spectral response and a comparison of the instrument data with theoretical predictions and optical simulations.
LiteBIRD is a candidate for JAXA’s strategic large mission to observe the cosmic microwave background (CMB) polarization over the full sky at large angular scales. It is planned to be launched in the 2020s with an H3 launch vehicle for three years of observations at a Sun-Earth Lagrangian point (L2). The concept design has been studied by researchers from Japan, U.S., Canada and Europe during the ISAS Phase-A1. Large scale measurements of the CMB B-mode polarization are known as the best probe to detect primordial gravitational waves. The goal of LiteBIRD is to measure the tensor-to-scalar ratio (r) with precision of r < 0:001. A 3-year full sky survey will be carried out with a low frequency (34 - 161 GHz) telescope (LFT) and a high frequency (89 - 448 GHz) telescope (HFT), which achieve a sensitivity of 2.5 μK-arcmin with an angular resolution 30 arcminutes around 100 GHz. The concept design of LiteBIRD system, payload module (PLM), cryo-structure, LFT and verification plan is described in this paper.
In this paper we discuss the latest developments of the STRIP instrument of the “Large Scale Polarization Explorer” (LSPE) experiment. LSPE is a novel project that combines ground-based (STRIP) and balloon-borne (SWIPE) polarization measurements of the microwave sky on large angular scales to attempt a detection of the “B-modes” of the Cosmic Microwave Background polarization. STRIP will observe approximately 25% of the Northern sky from the “Observatorio del Teide” in Tenerife, using an array of forty-nine coherent polarimeters at 43 GHz, coupled to a 1.5 m fully rotating crossed-Dragone telescope. A second frequency channel with six-elements at 95 GHz will be exploited as an atmospheric monitor. At present, most of the hardware of the STRIP instrument has been developed and tested at sub-system level. System-level characterization, starting in July 2018, will lead STRIP to be shipped and installed at the observation site within the end of the year. The on-site verification and calibration of the whole instrument will prepare STRIP for a 2-years campaign for the observation of the CMB polarization.
We present a preliminary study of the sky scanning strategy for the LSPE-STRIP instrument, a ground-based telescope that will be installed at the Teide Observatory (Tenerife, Canary Islands) in early 2019 and will observe the polarized emission of about 25% of the sky in the Northern Hemisphere at 43 and 95 GHz. The same sky portion will be observed at 140, 220 and 240 GHz by LSPE-SWIPE, a stratospheric balloon scheduled for a long-duration flight around the North Pole during the Arctic winter of 2019/2020. The combination of data from the two instruments aims at constraining the tensor-to-scalar ratio down to r ~ 0.03. In our paper we discuss the main scanning strategy requirements (overlap with SWIPE coverage, sensitivity distribution, observation of calibration sources) and show how we obtain a trade-off by spinning the telescope around the azimuth axis with constant elevation and angular velocity. The combination of the telescope motion with the Earth rotation will guarantee the access to the large angular scales. We will observe periodically the Crab Nebula as well as the Perseus molecular cloud. The Crab is one of the best known polarized sources in the sky and it will be observed for calibration purposes. The second one is a source of Anomalous Microwave Emission that could be characterized both in intensity and polarization.
M. Bersanelli, A. Mennella, G. Morgante, M. Zannoni, G. Addamo, A. Baschirotto, P. Battaglia, A. Baù, B. Cappellini, F. Cavaliere, F. Cuttaia, F. Del Torto, S. Donzelli, Z. Farooqui, M. Frailis, C. Franceschet, E. Franceschi, T. Gaier, S. Galeotta, M. Gervasi, A. Gregorio, P. Kangaslahti, N. Krachmalnicoff, C. Lawrence, G. Maggio, R. Mainini, D. Maino, N. Mandolesi, B. Paroli, A. Passerini, O. Peverini, S. Poli, S. Ricciardi, M. Rossetti, M. Sandri, M. Seiffert, L. Stringhetti, A. Tartari, R. Tascone, D. Tavagnacco, L. Terenzi, M. Tomasi, E. Tommasi, F. Villa, Gi. Virone, A. Zacchei
We discuss the design and expected performance of STRIP (STRatospheric Italian Polarimeter), an array of coherent receivers designed to fly on board the LSPE (Large Scale Polarization Explorer) balloon experiment. The STRIP focal plane array comprises 49 elements in Q band and 7 elements in W-band using cryogenic HEMT low noise amplifiers and high performance waveguide components. In operation, the array will be cooled to 20 K and placed in the focal plane of a ~0.6 meter telescope providing an angular resolution of ~1.5 degrees. The LSPE experiment aims at large scale, high sensitivity measurements of CMB polarization, with multi-frequency deep measurements to optimize component separation. The STRIP Q-band channel is crucial to accurately measure and remove the synchrotron polarized component, while the W-band channel, together with a bolometric channel at the same frequency, provides a crucial cross-check for systematic effects.
S. Aiola, G. Amico, P. Battaglia, E. Battistelli, A. Baù, P. de Bernardis, M. Bersanelli, A. Boscaleri, F. Cavaliere, A. Coppolecchia, A. Cruciani, F. Cuttaia, A. D' Addabbo, G. D' Alessandro, S. De Gregori, F. Del Torto, M. De Petris, L. Fiorineschi, C. Franceschet, E. Franceschi, M. Gervasi, D. Goldie, A. Gregorio, V. Haynes, N. Krachmalnicoff, L. Lamagna, B. Maffei, D. Maino, S. Masi, A. Mennella, G. Morgante, F. Nati, M. W. Ng, L. Pagano, A. Passerini, O. Peverini, F. Piacentini, L. Piccirillo, G. Pisano, S. Ricciardi, P. Rissone, G. Romeo, M. Salatino, M. Sandri, A. Schillaci, L. Stringhetti, A. Tartari, R. Tascone, L. Terenzi, M. Tomasi, E. Tommasi, F. Villa, G. Virone, S. Withington, A. Zacchei, M. Zannoni
The LSPE is a balloon-borne mission aimed at measuring the polarization of the Cosmic Microwave Background (CMB)
at large angular scales, and in particular to constrain the curl component of CMB polarization (B-modes) produced by
tensor perturbations generated during cosmic inflation, in the very early universe. Its primary target is to improve the
limit on the ratio of tensor to scalar perturbations amplitudes down to r = 0.03, at 99.7% confidence. A second target is
to produce wide maps of foreground polarization generated in our Galaxy by synchrotron emission and interstellar dust
emission. These will be important to map Galactic magnetic fields and to study the properties of ionized gas and of
diffuse interstellar dust in our Galaxy. The mission is optimized for large angular scales, with coarse angular resolution
(around 1.5 degrees FWHM), and wide sky coverage (25% of the sky). The payload will fly in a circumpolar long
duration balloon mission during the polar night. Using the Earth as a giant solar shield, the instrument will spin in
azimuth, observing a large fraction of the northern sky. The payload will host two instruments. An array of coherent
polarimeters using cryogenic HEMT amplifiers will survey the sky at 43 and 90 GHz. An array of bolometric
polarimeters, using large throughput multi-mode bolometers and rotating Half Wave Plates (HWP), will survey the same
sky region in three bands at 95, 145 and 245 GHz. The wide frequency coverage will allow optimal control of the
polarized foregrounds, with comparable angular resolution at all frequencies.
The ESA Planck mission is the third generation (after COBE and WMAP) space experiment dedicated to the measurement
of the Cosmic Microwave Background (CMB) anisotropies. Planck will map the whole CMB sky using two instruments in
the focal plane of a 1.5 m off-axis aplanatic telescope. The High Frequency Instrument (HFI) is an array of 52 bolometers
in the frequency range 100-857 GHz, while the Low Frequency Instrument (LFI) is an array of 11 pseudo-correlation
radiometric receivers which continuously compare the sky signal with the reference signal of a blackbody at ~ 4.5 K.
The LFI has been tested and calibrated at different levels of integration, i.e. on the single units (feed-horns, OMTs, amplifiers,
waveguides, etc.), on each integrated Radiometric Chain Assembly (RCA) and finally on the complete instrument,
the Radiometric Array Assembly (RAA). In this paper we focus on some of the data analysis algorithms and methods that
have been implemented to estimate the instrument performance and calibration parameters.
The paper concludes with the discussion of a custom-designed software package (LIFE) that allows to access the
complex data structure produced by the instrument and to estimate the instrument performance and calibration parameters
via a fully graphical interface.
A. Mennella, B. Aja, E. Artal, M. Balasini, G. Baldan, P. Battaglia, T. Bernardino, M. Bersanelli, E. Blackhurst, L. Boschini, C. Burigana, R. Butler, B. Cappellini, F. Colombo, F. Cuttaia, O. D'Arcangelo, S. Donzelli, R. Davis, L. De La Fuente, F. Ferrari, L. Figini, S. Fogliani, C. Franceschet, E. Franceschi, T. Gaier, S. Galeotta, S. Garavaglia, A. Gregorio, M. Guerrini, R. Hoyland, N. Hughes, P. Jukkala, D. Kettle, M. Laaninen, P. Lapolla, D. Lawson, R. Leonardi, P. Leutenegger, G. Mari, P. Meinhold, M. Miccolis, D. Maino, M. Malaspina, N. Mandolesi, M. Maris, E. Martinez-Gonzalez, G. Morgante, L. Pagan, F. Pasian, P. Platania, M. Pecora, S. Pezzati, L. Popa, T. Poutanen, M. Pospieszalski, N. Roddis, M. Salmon, M. Sandri, R. Silvestri, A. Simonetto, C. Sozzi, L. Stringhetti, L. Terenzi, M. Tomasi, J. Tuovinen, L. Valenziano, J. Varis, F. Villa, A. Wilkinson, F. Winder, A. Zacchei
In this paper we present the test results of the qualification model (QM) of the LFI instrument, which is being
developed as part of the ESA Planck satellite. In particular we discuss the calibration plan which has defined
the main requirements of the radiometric tests and of the experimental setups. Then we describe how these
requirements have been implemented in the custom-developed cryo-facilities and present the main results. We
conclude with a discussion of the lessons learned for the testing of the LFI Flight Model (FM).
KEYWORDS: Thermal modeling, Instrument modeling, Data modeling, Temperature metrology, Bolometers, Satellites, Space telescopes, Cooling systems, Anisotropy, Space operations
The ESA Planck mission is the third generation (after COBE and WMAP) space experiment dedicated to the measurement of the Cosmic Microwave Background (CMB) anisotropies. Two instruments will be integrated onboard: the High Frequency Instrument (HFI), an array of bolometers, and the Low Frequency Instrument (LFI), an array of pseudo-correlation HEMT radiometers.
In this paper we will discuss the development of analytical and numerical models to estimate the thermal behavior of LFI, both in steady-state and transient conditions. We then describe their application to the qualification model (QM) tests. QM test data were also used to calibrate the numerical models. Finally, we show some examples about how these models can be used in predicting the instrument performances and the impact of thermal systematic effects on the scientific results.
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