<i>Planck</i>pre-launch status: HFI ground calibration

Thermal Kinetic-Inductance Detectors (TKIDs) combine the excellent noise performance of traditional bolometers with a radio frequency multiplexing architecture that enables the large detector counts needed for the next generation of millimeter-wave instruments. In this paper, we first discuss the expected noise sources in TKIDs and derive the limits where the phonon noise contribution dominates over the other detector noise terms: generation-recombination, amplifier, and two-level system noise. Second, we characterize aluminum TKIDs in a dark environment. We present measurements of TKID resonators with quality factors of about 10 5 at 80 mK. We also discuss the bolometer thermal conductance, heat capacity, and time constants. These were measured by the use of a resistor on the thermal island to excite the bolometers. These dark aluminum TKIDs demonstrate a noise equivalent power, NEP = 2 Â 10 À17 W= ffiffiffiffiffiffi Hz p , with a 1=f knee at 0.1 Hz, which provides background noise limited performance for ground-based telescopes observing at 150 GHz.

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“…The non-linearity level is similar to that of semiconducting NTD Ge bolometers that operate with small correction factors. 86,87…”

Section: Responsivitymentioning

confidence: 99%

Thermal kinetic inductance detectors for millimeter-wave detection

Wandui

Bock

Frez

et al. 2020

Journal of Applied Physics

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“…Here τ(ν) is theétendue-normalized detector spectral response function (SRF), (Pajot et al 2010;Ade et al 2010;Planck Collaboration IX 2014), P(θ, φ) is the instrument scanning beam, normalized to unity at its peak, Ω p,i is the timevarying planetary solid angle as seen by the detector, and Ω b is the scanning-beam solid angle, Ω b = dΩP(θ, φ). The first and second integrals are over solid angle covered by the planet disc and over frequency, respectively.…”

Section: Signal Estimatesmentioning

confidence: 99%

Planckintermediate results

Akrami

Ashdown

Aumont

et al. 2017

A&A

Self Cite

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Measurements of flux density are described for five planets, Mars, Jupiter, Saturn, Uranus, and Neptune, across the six Planck High Frequency Instrument frequency bands (100-857 GHz) and these are then compared with models and existing data. In our analysis, we have also included estimates of the brightness of Jupiter and Saturn at the three frequencies of the Planck Low Frequency Instrument (30, 44, and 70 GHz). The results provide constraints on the intrinsic brightness and the brightness time-variability of these planets. The majority of the planet flux density estimates are limited by systematic errors, but still yield better than 1% measurements in many cases. Applying data from Planck HFI, the Wilkinson Microwave Anisotropy Probe (WMAP), and the Atacama Cosmology Telescope (ACT) to a model that incorporates contributions from Saturn's rings to the planet's total flux density suggests a best fit value for the spectral index of Saturn's ring system of β ring = 2.30 ± 0.03 over the 30-1000 GHz frequency range. Estimates of the polarization amplitude of the planets have also been made in the four bands that have polarizationsensitive detectors (100-353 GHz); this analysis provides a 95 % confidence level upper limit on Mars's polarization of 1.8, 1.7, 1.2, and 1.7 % at 100, 143, 217, and 353 GHz, respectively. The average ratio between the Planck-HFI measurements and the adopted model predictions for all five planets (excluding Jupiter observations for 353 GHz) is 0.997, 0.997, 1.018, and 1.032 for 100, 143, 217, and 353 GHz, respectively. Model predictions for planet thermodynamic temperatures are therefore consistent with the absolute calibration of Planck-HFI detectors at about the three-percent-level. We compare our measurements with published results from recent cosmic microwave background experiments. In particular, we observe that the flux densities measured by Planck HFI and WMAP agree to within 2 %. These results allow experiments operating in the mm-wavelength range to cross-calibrate against Planck and improve models of radiative transport used in planetary science.

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“…This external calibration source will be located in the far-field of the interferometer, at about 40 m from the instrument and it will be mounted on top of a tower near the instrument shelter inside an insulation box suitable to maintain the device within a specified temperature range. In addition, two carbon fiber sources located inside the cryostat, just next to to the array of back-to-back horns and switches, will also be used for calibration purposes [45].…”

Section: Measuring Primordial B-modes With Qubicmentioning

confidence: 99%

QUBIC: Observing the Polarized Microwave Sky over the Puna

Cosmology¹

2020

scirevfew

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QUBIC (Q&U Bolometric Interferometer for Cosmology) is an experiment designed to measure the polarization of the cosmic microwave background (CMB), the relic radiation from the Big- Bang. Detailed measurements of tiny temperature anisotropies in the CMB shaped our understanding of the early Universe. Accurate measurements of its polarization may reveal even earlier features, in particular the presence of gravitational waves with primordial origin. Such measurements can probe inflationary cosmological models, which postulate that quantum effects during an accelerated expansion at the earliest stages after the Big-Bang produced gravitational waves along with the density fluctuations that later seeded galaxy formation. QUBIC will join other international efforts currently pursuing this goal using a novel approach, which combines the sensitivity of bolometric detectors with the control of systematic effects provided by interferometry. After its current calibration phase is completed a technological demonstrator already constructed in European laboratories will be deployed in Alto Chorrillos, a site in the Puna near San Antonio de los Cobres, Salta, Argentina. The complete first module of the instrument is planned to be installed during 2020. We review the scientific goals of the project, the instrument design and its expected performance.

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Planckpre-launch status: HFI ground calibration

Cited by 27 publications

References 24 publications

Thermal kinetic inductance detectors for millimeter-wave detection

Thermal kinetic inductance detectors for millimeter-wave detection

Planckintermediate results

QUBIC: Observing the Polarized Microwave Sky over the Puna

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