A Continuous 100-mK Helium-Light Cooling System for MUSCAT on the LMT

Brien, T. L. R.; Castillo‐Domínguez, E.; Chase, S. T.; Doyle, S.

doi:10.1007/s10909-018-2024-y

Cited by 13 publications

(9 citation statements)

References 5 publications

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“…The focal plane is continuously maintained at 0.1 K. Several technologies including continuous adiabatic-demagnetization refrigerators [173,174] and continuouscycle dilution refrigerators [175] are either already near-mature, or should be mature by the 2030s. The focal plane module contains four elements: (1) low-pass filters rejecting electromagnetic (EM) radiation above the highest band (∼850 GHz); (2) monolithic arrays of thousands of pixel elements that couple the EM radiation from space to transmission lines, which then channel the power to transition-edge-sensor (TES) bolometers converting the deposited power to current signals; and (3) frontend SQUID amplifiers.…”

Section: Instrumentsmentioning

confidence: 99%

Microwave spectro-polarimetry of matter and radiation across space and time

et al. 2021

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This paper discusses the science case for a sensitive spectro-polarimetric survey of the microwave sky. Such a survey would provide a tomographic and dynamic census of the three-dimensional distribution of hot gas, velocity flows, early metals, dust, and mass distribution in the entire Hubble volume, exploit CMB temperature and polarisation anisotropies down to fundamental limits, and track energy injection and absorption into the radiation background across cosmic times by measuring spectral distortions of the CMB blackbody emission. In addition to its exceptional capability for cosmology and fundamental physics, such a survey would provide an unprecedented view of microwave emissions at sub-arcminute to few-arcminute angular resolution in hundreds of frequency channels, a data set that would be of immense legacy value for many branches of astrophysics. We propose that this survey be carried out with a large space mission featuring a broad-band polarised imager and a moderate resolution spectro-imager at the focus of a 3.5 m aperture telescope actively cooled to about 8K, complemented with absolutely-calibrated Fourier Transform Spectrometer modules observing at degree-scale angular resolution in the 10–2000 GHz frequency range. We propose two observing modes: a survey mode to map the entire sky as well as a few selected wide fields, and an observatory mode for deeper observations of regions of specific interest.

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Section: Instrumentsmentioning

confidence: 99%

Microwave spectro-polarimetry of matter and radiation across space and time

et al. 2021

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“…The design of MUSCAT's cooling system has been previously described 11 and utilises four different cooling systems to produce a continuous temperature, under the final loading, of 133 mK at the focal plane. Initial cooling of the 50-and 4-kelvin stages is performed using a Cryomech PT-420-RM which provides 2.0 W of cooling at 4.2 K. A 1-kelvin stage is cooled by a Chase Research Cryogenics 4 He continuous sorption cooler (CC4); this stage does not include a radiation shield and serves to buffer colder stages from thermal loading via the mechanical supports to the 4 K stage.…”

Section: Instrument Designmentioning

confidence: 99%

Pre-deployment verification and predicted mapping speed of MUSCAT

Brien

Ade

Barry

et al. 2020

Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy X

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The Mexico-UK Submillimetre Camera for AsTronomy (MUSCAT) is a 1.1 mm receiver consisting of 1,500 lumped-element kinetic inductance detectors (LEKIDs) for the Large Millimeter Telescope (LMT; Volcán Sierra Negra in Puebla, México). MUSCAT utilises the maximum field of view of the LMT's upgraded 50-metre primary mirror and is the first México-UK collaboration to deploy a millimetre/sub-mm receiver on the Large Millimeter Telescope. Using a simplistic simulator, we estimate a predicted mapping speed for MUSCAT by combining the measured performance of MUSCAT with the observed sky conditions at the LMT. We compare this to a previously calculated bolometric-model mapping speed and find that our mapping speed is in good agreement when this is scaled by a previously reported empirical factor. Through this simulation we show that signal contamination due to sky fluctuations can be effectively removed through the use of principle component analysis. We also give an overview of the instrument design and explain how this design allows for MUSCAT to be upgraded and act as an on-sky demonstration testbed for novel technologies after the facility-class TolTEC receiver comes online.

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“…The six arrays are mounted on the MUSCAT focal plane as shown in Figure 2, where they operate continuously at 130 mK through a novel closed-cycle cooling system described in Brien et al 13 Each of the six channels is readout by a pair of coaxial cables that are heat sunk at each temperature stage of the system (50 K, 4 K and 450 mK) before connecting to the array modules. In addition, DC blocks add further thermal isolation between the centre line of each cable between the 4 K and 450 mK stages.…”

Section: Detector Arrays Descriptionmentioning

confidence: 99%

“…Figure13. Heat map of the eccentricity of the MUSCAT focal plane detectors (channels 6 to 1 from left to right).…”

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confidence: 99%

MUSCAT focal plane verification

Tapia

Ade

Barry

et al. 2020

Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy X

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The Mexico-UK Submillimetre Camera for Astronomy (MUSCAT) is the second-generation large-format continuum camera operating in the 1.1 mm band to be installed on the 50-m diameter Large Millimeter Telescope (LMT) in Mexico. The focal plane of the instrument is made up of 1458 horn coupled lumped-element kinetic inductance detectors (LEKID) divided equally into six channels deposited on three silicon wafers. Here we present the preliminary results of the complete characterisation in the laboratory of the MUSCAT focal plane. Through the instrument's readout system, we perform frequency sweeps of the array to identify the resonance frequencies, and continuous timestream acquisitions to measure and characterise the intrinsic noise and 1/f knee of the detectors. Subsequently, with a re-imaging lens and a black body point source, the beams of every detector are mapped, obtaining a mean FWHM size of ∼3.27 mm, close to the expected 3.1 mm. Then, by varying the intensity of a beam filling black body source, we measure the responsivity and noise power spectral density (PSD) for each detector under an optical load of 300 K, obtaining the noise equivalent power (NEP), with which we verify that the majority of the detectors are photon noise limited. Finally, using a Fourier Transform Spectrometer (FTS), we measure the spectral response of the instrument, which indicate a bandwidth of 1.0-1.2 mm centred on 1.1 mm, as expected.

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A Continuous 100-mK Helium-Light Cooling System for MUSCAT on the LMT

Cited by 13 publications

References 5 publications

Microwave spectro-polarimetry of matter and radiation across space and time

Microwave spectro-polarimetry of matter and radiation across space and time

Pre-deployment verification and predicted mapping speed of MUSCAT

MUSCAT focal plane verification

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