The Q/U Imaging Experiment Instrument

Bischoff, C. A.; Brizius, Alison; Buder, I.; Chinone, Yuji; Cleary, Kieran; Dumoulin, R. N.; Kusaka, A.; Monsalve, Raul A.; Næss, Sigurd; Newburgh, Laura; Nixon, G. W.; Reeves, R.; Smith, Kendrick M.; Vanderlinde, K.; Wehus, I. K.; Bogdan, M.; Bustos, R.; Church, S.; Davis, R. J.; Dickinson, C.; Eriksen, H. K.; Gaier, T.; Gundersen, Joshua O.; Hasegawa, M.; Hazumi, M.; Holler, C. M.; Huffenberger, K. M.; Imbriale, W.; Ishidoshiro, K.; Jones, Michael E.; Kangaslahti, Pekka; Kapner, D. J.; Lawrence, C. R.; Leitch, E. M.; Limon, M.; McMahon, Jeffrey; Miller, Amber; Nagai, Makoto; Nguyen, H. T.; Pearson, T. J.; Piccirillo, L.; Radford, Simon J. E.; Readhead, A. C. S.; Richards, J. L.; Samtleben, D. F. E.; Seiffert, M. D.; Shepherd, M. C.; Staggs, Suzanne T.; Tajima, O.; Thompson, K. L.; Williamson, A. R.; Winstein, B.; Wollack, Edward J.; Zwart, Jonathan T. L.

doi:10.1088/0004-637x/768/1/9

Cited by 53 publications

(36 citation statements)

References 39 publications

(49 reference statements)

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“…The off-axis optical system both enables a totally unobstructed view of the sky which minimizes telescope emissivity and uncontrolled sidelobes, and also leads to very low cross-polarization which makes it an excellent choice for CMB experiments. As such, the crossed-Dragone design was chosen for both the QUIET [94] and Atacama B-Mode Search experiments [95], and proposed for "Stage 4" CMB experiments [96]. Figure 7 shows the basic optical design.…”

Section: Telescope and Optical Designmentioning

confidence: 99%

CCAT-Prime: science with an ultra-widefield submillimeter observatory on Cerro Chajnantor

Stacey

Aravena

Basu

et al. 2018

Ground-Based and Airborne Telescopes VII

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We present the detailed science case, and brief descriptions of the telescope design, site, and first light instrument plans for a new ultra-wide field submillimeter observatory, CCAT-prime, that we are constructing at a 5600 m elevation site on Cerro Chajnantor in northern Chile. Our science goals are to study star and galaxy formation from the epoch of reionization to the present, investigate the growth of structure in the Universe, improve the precision of B-mode CMB measurements, and investigate the interstellar medium and star formation in the Galaxy and nearby galaxies through spectroscopic, polarimetric, and broadband surveys at wavelengths from 200 m to 2 mm. These goals are realized with our two first light instruments, a large field-of-view (FoV) bolometer-based imager called Prime-Cam (that has both camera and an imaging spectrometer modules), and a multi-beam submillimeter heterodyne spectrometer, CHAI. CCAT-prime will have very high surface accuracy and very low system emissivity, so that combined with its wide FoV at the unsurpassed CCAT site our telescope/instrumentation combination is ideally suited to pursue this science. The CCAT-prime telescope is being designed and built by Vertex Antennentechnik GmbH. We expect to achieve first light in the spring of 2021. 1 gjs12@cornell.edu; phone 1 (607) 255-5900

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Section: Telescope and Optical Designmentioning

confidence: 99%

CCAT-Prime: science with an ultra-widefield submillimeter observatory on Cerro Chajnantor

Stacey

Aravena

Basu

et al. 2018

Ground-Based and Airborne Telescopes VII

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“…This modulation results in induced polarization that tracks and measures the beam-averaged foreground spectrum, without relying on, e.g., polynomial model fits, and is insensitive to the spatially uniform 21 cm signal. CMB polarization measurements use analogous modulation approaches, achieving stability and systematic control required for mK polarimetric sensitivity (e.g., Bennett et al 2003;Bischoff et al 2013).…”

Section: The Dare Science Instrumentmentioning

confidence: 99%

A Space-based Observational Strategy for Characterizing the First Stars and Galaxies Using the Redshifted 21 cm Global Spectrum

Burns

Bradley

Tauscher

et al. 2017

ApJ

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The redshifted 21 cm monopole is expected to be a powerful probe of the epoch of the first stars and galaxies ( < < z 10 35). The global 21 cm signal is sensitive to the thermal and ionization state of hydrogen gas and thus provides a tracer of sources of energetic photons-primarily hot stars and accreting black holes-which ionize and heat the high redshift intergalactic medium (IGM). This paper presents a strategy for observations of the global spectrum with a realizable instrument placed in a low-altitude lunar orbit, performing night-time 40-120 MHz spectral observations, while on the farside to avoid terrestrial radio frequency interference, ionospheric corruption, and solar radio emissions. The frequency structure, uniformity over large scales, and unpolarized state of the redshifted 21 cm spectrum are distinct from the spectrally featureless, spatially varying, and polarized emission from the bright foregrounds. This allows a clean separation between the primordial signal and foregrounds. For signal extraction, we model the foreground, instrument, and 21 cm spectrum with eigenmodes calculated via Singular Value Decomposition analyses. Using a Markov Chain Monte Carlo algorithm to explore the parameter space defined by the coefficients associated with these modes, we illustrate how the spectrum can be measured and how astrophysical parameters (e.g., IGM properties, first star characteristics) can be constrained in the presence of foregrounds using the Dark Ages Radio Explorer (DARE).

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“…CD telescopes were used for CMB measurements for the first time in the last decade on two small aperture (< 2 m) instruments [15,16], and were proposed in a concept paper for NASA's Inflation Probe [17]. All of these 1 We note that the mapping speed of a CMB instrument scales linearly with the number of detectors assuming a constant noise level per detector, or as the inverse square of the instrument noise equivalent temperature, NET −2 .…”

Section: Crossed-dragone Telescopesmentioning

confidence: 99%

“…In the Atacama B-mode Search [16] the telescope mirrors and baffles are cooled to ∼4 K temperatures to minimize loading and photon noise from the baffles. In the Q/U Imaging Experiment [15] coherent detectors are used to directly measure the polarization signal, thereby reducing sensitivity to unpolarized emission from the ambient temperature baffles.…”

Section: Crossed-dragone Telescopesmentioning

confidence: 99%

Designs for a large-aperture telescope to map the CMB 10× faster

Niemack

2016

Appl. Opt.

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Current large-aperture cosmic microwave background (CMB) telescopes have nearly maximized the number of detectors that can be illuminated while maintaining diffraction-limited image quality. The polarization-sensitive detector arrays being deployed in these telescopes in the next few years will have roughly 10 4 detectors. Increasing the mapping speed of future instruments by at least an order of magnitude is important to enable precise probes of the inflationary paradigm in the first fraction of a second after the big bang and provide strong constraints on cosmological parameters. The CMB community has begun planning a next generation "Stage IV" CMB project that will be comprised of multiple telescopes with between 10 5 -10 6 detectors to pursue these goals. This paper introduces new crossed Dragone telescope and receiver optics designs that increase the usable diffraction-limited field-of-view, and therefore the mapping speed, by an order of magnitude compared to the upcoming generation of large-aperture instruments. Polarization systematics and engineering considerations are presented, including a preliminary receiver model to demonstrate that these designs will enable high efficiency illumination of > 10 5 detectors in a next generation CMB telescope. http://dx.doi.org/XXXXXX Recent measurements of the Cosmic Microwave Background (CMB) led to detections of several new cosmological signals, including gravitational lensing of the CMB, approximately masslimited galaxy cluster catalogs, and, most recently, the "B-mode" polarization [e.g. 1-4]. This rapid progress has been enabled by the development of large arrays of background-limited lowtemperature detectors. These detector arrays are typically designed to fill a large fraction of the diffraction-limited field-ofview (DLFOV) on each telescope. The upcoming generation of large-aperture (> 2 meter) CMB instruments includes: the Simons Array of three 2.5 meter telescopes [5], Advanced ACTPol on the 6 meter Atacama Cosmology Telescope [6], and SPT-3G on the 10 meter South Pole Telescope [7]. Each will nearly fill the DLFOV of these existing telescopes with roughly 10 4 detectors operating between 30 GHz -300 GHz.Beyond this coming generation of instruments, there is potential for substantial improvements in constraints on signals from inflationary gravity waves, neutrino properties, and other cosmological parameters if CMB measurements can be made with sufficient sensitivity and angular resolution [e.g., 8-10]. The CMB community has begun planning for a "Stage IV" CMB survey with between 10 5 -10 6 detectors to achieve these scientific goals, including a precise probe of the inflationary tensor-toscalar ratio, r < 0.001 [8]. Since current telescopes do not have sufficient throughput to illuminate > 10 5 detectors, it is important to develop designs for higher-throughput telescopes.We explore a new parameter space of CMB telescope designs that offer roughly 10× greater throughput than existing telescopes. In §1 we quantify the diffraction-limited throughput tradeof...

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The Q/U Imaging Experiment Instrument

Cited by 53 publications

References 39 publications

CCAT-Prime: science with an ultra-widefield submillimeter observatory on Cerro Chajnantor

CCAT-Prime: science with an ultra-widefield submillimeter observatory on Cerro Chajnantor

A Space-based Observational Strategy for Characterizing the First Stars and Galaxies Using the Redshifted 21 cm Global Spectrum

Designs for a large-aperture telescope to map the CMB 10× faster

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