Systematic uncertainties in the Simons Observatory: optical effects and sensitivity considerations

Gallardo, Patricio A.; Gudmundsson, J. E.; Koopman, Brian J.; Matsuda, Frederick; Simon, Sara M.; Ali, Aamir; Bryan, Sean; Chinone, Yuji; Coppi, Gabriele; Cothard, Nicholas F.; Devlin, Mark J.; Dicker, Simon; Fabbian, Giulio; Galitzki, Nicholas; Hill, Charles A.; Keating, Brian; Kusaka, A.; Lashner, Jacob; Lee, Adrian T.; Limon, M.; Mauskopf, Philip Daniel; McMahon, Jeff; Nati, F.; Niemack, Michael D.; Orlowski-Scherer, John; Parshley, Stephen C.; Puglisi, Giuseppe; Reichardt, Christian; Salatino, Maria; Staggs, Suzanne T.; Suzuki, Aritoki; Vavagiakis, Eve M.; Wollack, Edward J.; Xu, Zhilei; Zhu, Ningfeng

doi:10.1117/12.2312971

Cited by 14 publications

(20 citation statements)

References 28 publications

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“…For this purpose, and to construct sky maps from the simulated TOD, we use the public Python package s4cmb 1 [14]. This software, which is derived from the POLARBEAR data analysis systematics pipeline, has been used to perform a preliminary systematics study for SO [10,15,16], and to explore the effects of systematics on B-mode measurements on real data [7,17]. Injecting systematics directly into the simulated detector-by-detector TOD allows us to explore a wider set of systematics in a more realistic way than other possible treatments of systematics (such as effective induced map-domain systematics), and includes their variation across the focal plane of the instrument.…”

Section: Instrumental Systematics Simulationsmentioning

confidence: 99%

“…In our simulations, we do not model the cross-polar beam response. This response is expected to be subdominant for an SO-like instrument based on modern optical coupling technologies for bolometric detectors and cross-Dragone telescopes [10,15]. We also assume that all baseline beams have a perfect circular shape with a Gaussian radial profile.…”

Section: A Beam Ellipticitymentioning

confidence: 99%

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Instrumental systematics biases in CMB lensing reconstruction: A simulation-based assessment

et al. 2021

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Weak gravitational lensing of the cosmic microwave background (CMB) is an important cosmological tool that allows us to learn about the structure, composition and evolution of the Universe. Upcoming CMB experiments, such as the Simons Observatory (SO), will provide high-resolution and low-noise CMB measurements. We consider the impact of instrumental systematics on the corresponding high-precision lensing reconstruction power spectrum measurements. We simulate CMB temperature and polarization maps for an SO-like instrument and potential scanning strategy, and explore systematics relating to beam asymmetries and offsets, boresight pointing, polarization angle, gain drifts, gain calibration and electric crosstalk. Our analysis shows that the majority of the biases induced by the systematics we modeled are below a detection level of ∼ 0.6σ. We discuss potential mitigation techniques to further reduce the impact of the more significant systematics, and pave the way for future lensing-related systematics analyses.

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Section: Instrumental Systematics Simulationsmentioning

confidence: 99%

Section: A Beam Ellipticitymentioning

confidence: 99%

Instrumental systematics biases in CMB lensing reconstruction: A simulation-based assessment

et al. 2021

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“…Note however that this accounts only for the wavefront errors due to the optics -manufacturing and alignment errors are not included. Given that one obvious application of this very large field of view would be for observations of CMB polarization, an investigation of the polarization properties of the modified design was conducted in GRASP 22 and is discussed in Gallardo et al 2018. It was found that the shaping maintains the very low cross polarization intrinsic to the Dragone design.…”

Section: Coma Correctionmentioning

confidence: 99%

“…A CCAT first-light camera design is discussed in Vavagiakis et al 2018 7 . An SO science book is in development, an overview of SO instrumentation is presented in Galitzki et al 2018 8 , optical systematics for this telescope design are described in Gallardo et al 2018 9 , cryogenic optics designs are in Dicker et al 2018 10 , and design analyses for the SO LAT receiver are presented in Zhu et al 2018 11 , Orlowski-Scherer et al 2018 12 , and Coppi et al 2018 13 .…”

Section: Introductionmentioning

confidence: 99%

The optical design of the six-meter CCAT-prime and Simons Observatory telescopes

Parshley¹,

Niemack²,

Hills³

et al. 2018

Ground-Based and Airborne Telescopes VII

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A common optical design for a coma-corrected, 6-meter aperture, crossed-Dragone telescope has been adopted for the CCAT-prime telescope of CCAT Observatory, Inc., and for the Large Aperture Telescope of the Simons Observatory. Both are to be built in the high altitude Atacama Desert in Chile for submillimeter and millimeter wavelength observations, respectively. The design delivers a high throughput, relatively flat focal plane, with a field of view 7.8 degrees in diameter for 3 mm wavelengths, and the ability to illuminate >100k diffraction-limited beams for < 1 mm wavelengths. The optics consist of offset reflecting primary and secondary surfaces arranged in such a way as to satisfy the Mizuguchi-Dragone criterion, suppressing first-order astigmatism and maintaining high polarization purity. The surface shapes are perturbed from their standard conic forms in order to correct coma aberrations. We discuss the optical design, performance, and tolerancing sensitivity. More information about CCAT-prime can be found at ccatobservatory.org and about Simons Observatory at simonsobservatory.org.

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“…The LAT has a 6 m-diameter primary mirror, a 7.8 degree FOV, and up to 13 cameras in a 2.4 m diameter receiver that cover more than a decade in frequency. 15,41,43 Motivated by the immensity and complexity of the LAT system, effort has been devoted to understanding and controlling ambient-temperature spillover and scattering, 40 as minimizing optical loading is critical to maintaining low NEP ph . Figure 6 shows relative in-band optical power and MS in each frequency band as a function of LAT primary spillover fraction.…”

Section: Lat Primary Spillovermentioning

confidence: 99%

BoloCalc: a sensitivity calculator for the design of Simons Observatory

Hill

Bruno

Simon

et al. 2018

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

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The Simons Observatory (SO) is an upcoming experiment that will study temperature and polarization fluctuations in the cosmic microwave background (CMB) from the Atacama Desert in Chile. SO will field both a large aperture telescope (LAT) and an array of small aperture telescopes (SATs) that will observe in six bands with center frequencies spanning from 27 to 270 GHz. Key considerations during the SO design phase are vast, including the number of cameras per telescope, focal plane magnification and pixel density, in-band optical power and camera throughput, detector parameter tolerances, and scan strategy optimization. To inform the SO design in a rapid, organized, and traceable manner, we have created a Python-based sensitivity calculator with several state-of-the-art features, including detector-to-detector optical white-noise correlations, a handling of simulated and measured bandpasses, and propagation of low-level parameter uncertainties to uncertainty in on-sky noise performance. We discuss the mathematics of the sensitivity calculation, the calculator's object-oriented structure and key features, how it has informed the design of SO, and how it can enhance instrument design in the broader CMB community, particularly for CMB-S4. Seven cameras are planned for initial deployment within the LAT receiver.† The LAT is designed with a larger FOV that can accommodate up to nineteen cameras, allowing for future LAT receiver upgrades.

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Systematic uncertainties in the Simons Observatory: optical effects and sensitivity considerations

Cited by 14 publications

References 28 publications

Instrumental systematics biases in CMB lensing reconstruction: A simulation-based assessment

Instrumental systematics biases in CMB lensing reconstruction: A simulation-based assessment

The optical design of the six-meter CCAT-prime and Simons Observatory telescopes

BoloCalc: a sensitivity calculator for the design of Simons Observatory

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