Low-Temperature Detectors for CMB Imaging Arrays

Hubmayr, Johannes; Austermann, J. E.; Beall, James A.; Becker, Daniel; Dober, Bradley; Duff, Shannon M.; Gao, Jiansong; Hilton, G. C.; McKenney, Christopher; Ullom, Joel N.; Lanen, Jeff Van

doi:10.1007/s10909-018-2029-6

Cited by 11 publications

(4 citation statements)

References 85 publications

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“…The MF receivers will employ spline-profiled feedhorn arrays which are machined out of aluminum and then gold plated [38,39]. A waveguide section of the feedhorns then couples the incoming radiation to bolometer arrays [40]. The feedhorns have 5.15-mm apertures and 0.15 mm wall thickness between feeds.…”

Section: B Pixel Beam Modelmentioning

confidence: 99%

The Simons Observatory: modeling optical systematics in the Large Aperture Telescope

Gudmundsson¹,

Gallardo²,

Puddu³

et al. 2021

Appl. Opt.

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We present geometrical and physical optics simulation results for the Simons Observatory Large Aperture Telescope. This work was developed as part of the general design process for the telescope, allowing us to evaluate the impact of various design choices on performance metrics and potential systematic effects. The primary goal of the simulations was to evaluate the final design of the reflectors and the cold optics that are now being built. We describe nonsequential ray tracing used to inform the design of the cold optics, including absorbers internal to each optics tube. We discuss ray tracing simulations of the telescope structure that allow us to determine geometries that minimize detector loading and mitigate spurious near-field effects that have not been resolved by the internal baffling. We also describe physical optics simulations, performed over a range of frequencies and field locations, that produce estimates of monochromatic far-field beam patterns, which in turn are used to gauge general optical performance. Finally, we describe simulations that shed light on beam sidelobes from panel gap diffraction.

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Section: B Pixel Beam Modelmentioning

confidence: 99%

The Simons Observatory: modeling optical systematics in the Large Aperture Telescope

Gudmundsson¹,

Gallardo²,

Puddu³

et al. 2021

Appl. Opt.

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“…At 2.3:1 bandwidth, the planar orthomode transducer (OMT) supports multiple waveguide modes; however, we only wish to couple the TES to the TE 11 mode because it exhibits a well defined polarization state. Furthermore, coupling the TES to higher-order modes is undesirable as it degrades angular resolution [12]. In the A-type, filtered passbands are routed to a structure known as a hybrid tee, which takes the input from two ports and produces sum and difference outputs.…”

Section: Design and Simulated Performancementioning

confidence: 99%

Demonstration of 220/280 GHz Multichroic Feedhorn-Coupled TES Polarimeter

et al. 2020

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We describe the design and measurement of feedhorn-coupled, transition-edge sensor (TES) polarimeters with two passbands centered at 220 GHz and 280 GHz, intended for observations of the cosmic microwave background. Each pixel couples polarized light in two linear polarizations by use of a planar orthomode transducer and senses power via four TES bolometers, one for each band in each linear polarization. Previous designs of this detector architecture incorporated passbands from 27 GHz to 220 GHz; we now demonstrate this technology at frequencies up to 315 GHz. Observational passbands are defined with an on-chip diplexer, and Fourier-transform-spectrometer measurements are in excellent agreement with simulations. After accounting for expected losses in our detector system, we find coupling from feedhorn to TES bolometer using a cryogenic, temperature-controlled thermal source is as expected. Relative to a detector with no losses and the designed passbands, our device is 95% (86%) efficient in the 220 (280) GHz band. Lastly, we compare two powertermination schemes commonly used in wide-bandwidth millimeter-wave polarimeters and find equal performance in terms of optical efficiency and passband shape.The cosmic microwave background (CMB) provides a powerful probe of the earliest moments of the universe. Precision measurements of CMB temperature and polarization anisotropies have played a crucial role in shaping our understanding of how the universe formed by providing rigorous constraints [1] on parameters of the standard cosmological model, Λ CDM. However, millimeter-wave observations are complicated by the presence of astrophysical foregrounds, such as synchrotron emission and galactic dust, which also radiate at

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“…Photolithography fabricated TES bolometer arrays have been fielded in numerous experiments to date; they are also being developed for near-term experiments and may be important for CMB-S4. 242…”

Section: Transition Edge Sensorsmentioning

confidence: 99%

Enabling discoveries: a review of 30 years of advanced technologies and instrumentation at the National Science Foundation

Kurczynski

Milojević

2020

J. Astron. Telesc. Instrum. Syst.

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Over its more than 30-year history, the Advanced Technologies and Instrumentation (ATI) program has provided grants to support technology development and instrumentation for ground-based astronomy. Through a combination of automated literature assessment and indepth literature review, we present a survey of ATI-funded research and its impact on astronomy and society. Award acknowledgment and literature citation statistics for ATI are comparable to a comparison astronomy grant program that does not support technology development. Citation statistics for both NSF-funded programs exceed those of the general astronomical literature. Numerous examples demonstrate the significant, long-term impact of ATI-supported research in astronomy. As part of this impact, ATI grants have provided many early career researchers the opportunity to gain critical professional experience. However, technology development unfolds over a time period that is longer than an individual grant. A longitudinal perspective shows that investments in technology and instrumentation have led to extraordinary scientific progress. © The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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Low-Temperature Detectors for CMB Imaging Arrays

Cited by 11 publications

References 85 publications

The Simons Observatory: modeling optical systematics in the Large Aperture Telescope

The Simons Observatory: modeling optical systematics in the Large Aperture Telescope

Demonstration of 220/280 GHz Multichroic Feedhorn-Coupled TES Polarimeter

Enabling discoveries: a review of 30 years of advanced technologies and instrumentation at the National Science Foundation

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