A simple method to measure the temperature and levitation height of devices rotating at cryogenic temperatures

Bernardis, P. de; Columbro, F.; Masi, S.; Paiella, A.; Romeo, G.

doi:10.1063/5.0005498

Cited by 16 publications

(11 citation statements)

References 23 publications

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“…An innovative frictionless clamp/release device [85], based on electromagnetic actuators, keeps the rotor in position at room temperature, and releases it below the superconductive transition temperature, when magnetic levitation works properly. A simple method to measure the temperature and levitation height of the HWP rotating at cryogenic temperatures was developed specifically for LSPE-SWIPE [86].…”

Section: Polarization Modulatormentioning

confidence: 99%

The large scale polarization explorer (LSPE) for CMB measurements: performance forecast

Addamo

Ade

Baccigalupi

et al. 2021

J. Cosmol. Astropart. Phys.

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The measurement of the polarization of the Cosmic Microwave Background (CMB) radiation is one of the current frontiers in cosmology. In particular, the detection of the primordial divergence-free component of the polarization field, the B-mode, could reveal the presence of gravitational waves in the early Universe. The detection of such a component is at the moment the most promising technique to probe the inflationary theory describing the very early evolution of the Universe. We present the updated performance forecast of the Large Scale Polarization Explorer (LSPE), a program dedicated to the measurement of the CMB polarization. LSPE is composed of two instruments: LSPE-Strip, a radiometer-based telescope on the ground in Tenerife-Teide observatory, and LSPE-SWIPE (Short-Wavelength Instrument for the Polarization Explorer) a bolometer-based instrument designed to fly on a winter arctic stratospheric long-duration balloon. The program is among the few dedicated to observation of the Northern Hemisphere, while most of the international effort is focused into ground-based observation in the Southern Hemisphere. Measurements are currently scheduled in Winter 2022/23 for LSPE-SWIPE, with a flight duration up to 15 days, and in Summer 2022 with two years observations for LSPE-Strip. We describe the main features of the two instruments, identifying the most critical aspects of the design, in terms of impact on the performance forecast. We estimate the expected sensitivity of each instrument and propagate their combined observing power to the sensitivity to cosmological parameters, including the effect of scanning strategy, component separation, residual foregrounds and partial sky coverage. We also set requirements on the control of the most critical systematic effects and describe techniques to mitigate their impact. LSPE will reach a sensitivity in tensor-to-scalar ratio of σ r < 0.01, set an upper limit r < 0.015 at 95% confidence level, and improve constraints on other cosmological parameters.

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Section: Polarization Modulatormentioning

confidence: 99%

The large scale polarization explorer (LSPE) for CMB measurements: performance forecast

Addamo

Ade

Baccigalupi

et al. 2021

J. Cosmol. Astropart. Phys.

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“…The PMU is also equipped with a custom capacitive sensors to measure the temperature and levitation height of the rotor. 22 The temperature sensor is a thermistor, physically mounted on the rotating device and biased with an AC current, which is transferred from the stationary electronics to the rotating device via capacitive coupling. The levitation height sensor is a network of capacitors, similar to the one used for the capacitive coupling of the thermistor.…”

Section: Baseline Designmentioning

confidence: 99%

A Polarization Modulator Unit for the Mid- and High-Frequency Telescopes of the LiteBIRD mission

Columbro,

de Bernardis,

Lamagna

et al. 2021

Preprint

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The LiteBIRD mission is a JAXA strategic L-class mission for all sky CMB surveys which will be launched in the 2020s. The main target of the mission is the detection of primordial gravitational waves with a sensitivity of the tensor-to-scalar ratio δr < 0.001. The polarization modulator unit (PMU) represents a critical and powerful component to suppress 1/f noise contribution and mitigate systematic uncertainties induced by detector gain drift, both for the high-frequency telescope (HFT) and for the mid-frequency telescope (MFT). Each PMU is based on a continuously-rotating transmissive half-wave plate (HWP) held by a superconducting magnetic bearing in a 5 K environment. In this proceeding we will present the design and expected performance of the LiteBIRD PMUs and testing performed on every PMU subsystem with a room-temperature rotating disk used as a stand-in for the cryogenic HWP rotor.

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“…An innovative frictionless clamp/release device [63], based on electromagnetic actuators, keeps the rotor in position at room temperature, and releases it below the superconductive transition temperature, when magnetic levitation works properly. A simple method to measure the temperature and levitation height of the HWP rotating at cryogenic temperatures was developed specifically for LSPE-SWIPE [64].…”

Section: Polarization Modulatormentioning

confidence: 99%

The large scale polarization explorer (LSPE) for CMB measurements: performance forecast

Addamo,

Ade,

Baccigalupi

et al. 2020

Preprint

View full text Add to dashboard Cite

The measurement of the polarization of the Cosmic Microwave Background (CMB) radiation is one of the current frontiers in cosmology. In particular, the detection of the primordial divergence-free component of the polarization field, the B-mode component, could reveal the presence of gravitational waves in the early Universe. The detection of such component is at the moment the most promising technique to probe the inflationary theory describing the very early evolution of the Universe. We present the updated performance forecast of the Large Scale Polarization Explorer (LSPE), a program dedicated to the measurement of the CMB polarization. LSPE is composed of two instruments: LSPE-Strip, a radiometer-based telescope on the ground in Tenerife, and LSPE-SWIPE (Short-Wavelength Instrument for the Polarization Explorer) a bolometer-based instrument designed to fly on a winter arctic stratospheric long-duration balloon. The program is among the few dedicated to observation of the Northern Hemisphere, while most of the international effort is focused into ground-based observation in the Southern Hemisphere. Measurements are currently scheduled in Winter 2021/22 for LSPE-SWIPE, with a flight duration up to 15 days, and in Summer 2021 with two years observations for LSPE-Strip. We describe the main features of the two instruments, identifying the most critical aspects of the design, in terms of impact into performance forecast. We estimate the expected sensitivity of each instrument and propagate their combined observing power to the sensitivity to cosmological parameters, including the effect of scanning strategy, component separation, residual foregrounds and partial sky coverage. We also set requirements on the control of the most critical systematic effects and describe techniques to mitigate their impact. LSPE can reach a sensitivity in tensor-to-scalar ratio of σ r < 0.01, and improve constrains on other cosmological parameters.

show abstract

A simple method to measure the temperature and levitation height of devices rotating at cryogenic temperatures

Abstract: A levitated magnetic dipole configuration as a compact charged particle trap Review of Scientific Instruments 91, 043507 (2020);

Cited by 16 publications

References 23 publications

The large scale polarization explorer (LSPE) for CMB measurements: performance forecast

The large scale polarization explorer (LSPE) for CMB measurements: performance forecast

A Polarization Modulator Unit for the Mid- and High-Frequency Telescopes of the LiteBIRD mission

The large scale polarization explorer (LSPE) for CMB measurements: performance forecast

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