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arXiv · 1807.03927

Design and characterization of the Cosmology Large Angular Scale Surveyor (CLASS) 93 GHz focal plane

Sumit Dahal·Aamir Ali·John W. Appel·Thomas Essinger-Hileman·Charles Bennett·Michael Brewer·Ricardo Bustos·Manwei Chan·David T. Chuss·Joseph Cleary·Felipe Colazo·Jullianna Couto·Kevin Denis·Rolando Dünner·Joseph Eimer·Trevor Engelhoven·Pedro Fluxa·Mark Halpern·Kathleen Harrington·Kyle Helson·Gene Hilton·Gary Hinshaw·Johannes Hubmayr·Jeffrey Iuliano·Tobias Marriage·Jeffrey McMahon·Nathan Miller·Carolina Nuñez·Ivan Padilla·Gonzalo Palma·Lucas Parker·Matthew Petroff·Bastian Pradenas·Rodrigo Reeves·Carl Reintsema·Karwan Rostem·Marco Sagliocca·Kongpop U-Yen·Deniz Valle·Bingjie Wang·Qinan Wang·Duncan Watts·Janet Weiland·Edward Wollack·Zhilei Xu·Ziang Yan·Lingzhen Zen
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Abstract

The Cosmology Large Angular Scale Surveyor (CLASS) aims to detect and characterize the primordial B-mode signal and make a sample-variance-limited measurement of the optical depth to reionization. CLASS is a ground-based, multi-frequency microwave polarimeter that surveys 70% of the microwave sky every day from the Atacama Desert. The focal plane detector arrays of all CLASS telescopes contain smooth-walled feedhorns that couple to transition-edge sensor (TES) bolometers through symmetric planar orthomode transducer (OMT) antennas. These low noise polarization-sensitive detector arrays are fabricated on mono-crystalline silicon wafers to maintain TES uniformity and optimize optical efficiency throughout the wafer. In this paper, we discuss the design and characterization of the first CLASS 93 GHz detector array. We measure the dark parameters, bandpass, and noise spectra of the detectors and report that the detectors are photon-noise limited. With current array yield of 82%, we estimate the total array noise-equivalent power (NEP) to be 2.1 aW$\sqrt[]{\mathrm{s}}$.

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Sumit Dahal, Aamir Ali, John W. Appel, Thomas Essinger-Hileman, Charles Bennett, Michael Brewer, Ricardo Bustos, Manwei Chan, David T. Chuss, Joseph Cleary, Felipe Colazo, Jullianna Couto, Kevin Denis, Rolando Dünner, Joseph Eimer, Trevor Engelhoven, Pedro Fluxa, Mark Halpern, Kathleen Harrington, Kyle Helson, Gene Hilton, Gary Hinshaw, Johannes Hubmayr, Jeffrey Iuliano, Tobias Marriage, Jeffrey McMahon, Nathan Miller, Carolina Nuñez, Ivan Padilla, Gonzalo Palma, Lucas Parker, Matthew Petroff, Bastian Pradenas, Rodrigo Reeves, Carl Reintsema, Karwan Rostem, Marco Sagliocca, Kongpop U-Yen, Deniz Valle, Bingjie Wang, Qinan Wang, Duncan Watts, Janet Weiland, Edward Wollack, Zhilei Xu, Ziang Yan, Lingzhen Zen. 2018-07-11. Design and characterization of the Cosmology Large Angular Scale Surveyor (CLASS) 93 GHz focal plane. https://doi.org/10.1117/12.2311812

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