A cryogenic continuously rotating half-wave plate mechanism for the POLARBEAR-2b cosmic microwave background receiver

Hill, Charles A.; Kusaka, A.; Ashton, Peter; Barton, Paul; Adkins, Tylor; Arnold, K.; Bixler, Bryce; Ganjam, Suhas; Lee, A. T.; Matsuda, Frederick; Matsumura, Tomotake; Sakurai, Y.; Tat, Raymond; Zhou, Y.

doi:10.1063/5.0029006

Cited by 18 publications

(8 citation statements)

References 73 publications

(148 reference statements)

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“…Based on these scaled model measurements, we confirmed the wide-field performance of LFT and the suppression of far sidelobes. POLARBEAR-2 and Simons Observatory [185][186][187]. Here we describe a summary of the current development status using the PMU breadboard model (BBM) during the conceptual design phase.…”

Section: Scaled Model Demonstrationmentioning

confidence: 99%

Probing cosmic inflation with theLiteBIRDcosmic microwave background polarization survey

Allys

Arnold

Aumont

et al. 2022

Progress of Theoretical and Experimental Physics

159

108

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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. The Japan Aerospace Exploration Agency (JAXA) selected LiteBIRD in May 2019 as a strategic large-class (L-class) mission, with an expected launch in the late 2020s using JAXA’s H3 rocket. LiteBIRD is planned to orbit the Sun-Earth Lagrangian point L2, where it will map the cosmic microwave background (CMB) polarization over the entire sky for three years, with three telescopes in 15 frequency bands between 34 and 448 GHz, to achieve an unprecedented total sensitivity of 2.2 μK-arcmin, with a typical angular resolution of 0.5○ at 100 GHz. The primary scientific objective of LiteBIRD is to 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 insight into the quantum nature of gravity and other new physics beyond the standard models of particle physics and cosmology. We provide an overview of the LiteBIRD project, including scientific objectives, mission and system requirements, operation concept, spacecraft and payload module design, expected scientific outcomes, potential design extensions and synergies with other projects. Subject Index LiteBIRD cosmic inflation, cosmic microwave background, B-mode polarization, primordial gravitational waves, quantum gravity, space telescope

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Section: Scaled Model Demonstrationmentioning

confidence: 99%

Probing cosmic inflation with theLiteBIRDcosmic microwave background polarization survey

Allys

Arnold

Aumont

et al. 2022

Progress of Theoretical and Experimental Physics

159

108

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“…QUBIC 1/85 s 370 <10 K SPIDER [25] 1/day 305 <10 K EBEX [21] <2 Hz 100 <10 K PILOT [26] 1/11.4 s 50 <10 K BLAST-POL [27] >1/6 s 105 120 K POLARBEAR [28,29] >2 Hz 440 50 K ACT-POL (ABS) [22] 2.5 Hz 324 Room temp. NIKA [23,30] 3 Hz 100 Room temp.…”

Section: Jcap04(2022)039mentioning

confidence: 99%

QUBIC VI: Cryogenic half wave plate rotator, design and performance

D’Alessandro¹,

Mele²,

Columbro³

et al. 2022

J. Cosmol. Astropart. Phys.

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Setting an upper limit or detection of B-mode polarization imprinted by gravitational waves from Inflation is one goal of modern large angular scale cosmic microwave background (CMB) experiments around the world. A great effort is being made in the deployment of many ground-based, balloon-borne and satellite experiments, using different methods to separate this faint polarized component from the incoming radiation. QUBIC exploits one of the most widely-used techniques to extract the input Stokes parameters, consisting in a rotating half-wave plate (HWP) and a linear polarizer to separate and modulate polarization components. QUBIC uses a step-by-step rotating HWP, with 15° steps, combined with a 0.4°s-1 azimuth sky scan speed. The rotation is driven by a stepper motor mounted on the cryostat outer shell to avoid heat load at internal cryogenic stages. The design of this optical element is an engineering challenge due to its large 370 mm diameter and the 8 K operation temperature that are unique features of the QUBIC experiment. We present the design for a modulator mechanism for up to 370 mm, and the first optical tests by using the prototype of QUBIC HWP (180 mm diameter). The tests and results presented in this work show that the QUBIC HWP rotator can achieve a precision of 0.15° in position by using the stepper motor and custom-made optical encoder. The rotation induces <5.0 mW (95% C.L) of power load on the 4 K stage, resulting in no thermal issues on this stage during measurements. We measure a temperature settle-down characteristic time of 28 s after a rotation through a 15° step, compatible with the scanning strategy, and we estimate a maximum temperature gradient within the HWP of ≤ 10 mK. This was calculated by setting up finite element thermal simulations that include the temperature profiles measured during the rotator operations. We report polarization modulation measurements performed at 150 GHz, showing a polarization efficiency >99% (68% C.L.) and a median cross-polarization χPol of 0.12%, with 71% of detectors showing a χPol + 2σ upper limit <1%, measured using selected detectors that had the best signal-to-noise ratio.

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“…The other solution is making the rotation stable, which makes the data more robust for offline data correction even if there were some faulty data. The cryogenic superconducting bearing technique developed for PB-2b, the second receiver of the Simons Array, is promising to achieve very stable rotation (Hill et al 2020).…”

Section: Example Of Data With the Angle Errormentioning

confidence: 99%

Improved Upper Limit on Degree-scale CMB B-mode Polarization Power from the 670 Square-degree POLARBEAR Survey

Adachi

Adkins

Faúndez

et al. 2022

ApJ

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We report an improved measurement of the degree-scale cosmic microwave background B-mode angular-power spectrum over 670 deg2 sky area at 150 GHz with Polarbear. In the original analysis of the data, errors in the angle measurement of the continuously rotating half-wave plate, a polarization modulator, caused significant data loss. By introducing an angle-correction algorithm, the data volume is increased by a factor of 1.8. We report a new analysis using the larger data set. We find the measured B-mode spectrum is consistent with the ΛCDM model with Galactic dust foregrounds. We estimate the contamination of the foreground by cross-correlating our data and Planck 143, 217, and 353 GHz measurements, where its spectrum is modeled as a power law in angular scale and a modified blackbody in frequency. We place an upper limit on the tensor-to-scalar ratio r < 0.33 at 95% confidence level after marginalizing over the foreground parameters.

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A cryogenic continuously rotating half-wave plate mechanism for the POLARBEAR-2b cosmic microwave background receiver

Cited by 18 publications

References 73 publications

Probing cosmic inflation with theLiteBIRDcosmic microwave background polarization survey

Probing cosmic inflation with theLiteBIRDcosmic microwave background polarization survey

QUBIC VI: Cryogenic half wave plate rotator, design and performance

Improved Upper Limit on Degree-scale CMB B-mode Polarization Power from the 670 Square-degree POLARBEAR Survey

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