The Simons Observatory 220 and 280 GHz Focal-Plane Module: Design and Initial Characterization

• Published in: arXiv.org
• Main Authors: Healy, Erin, Dutcher, Daniel, Atkins, Zachary, Austermann, Jason, Choi, Steve K, Duell, Cody J, Duff, Shannon, Galitzki, Nicholas, Huber, Zachary B, Hubmayr, Johannes, Johnson, Bradley R, McCarrick, Heather, Niemack, Michael D, Sonka, Rita, Staggs, Suzanne T, Vavagiakis, Eve, Wang, Yuhan, Xu, Zhilei, Zheng, Kaiwen
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 12.01.2022
• Subjects: Arrays; Focal plane; Modules; Multiplexers; Multiplexing; Noise levels; Observatories; Physics - Instrumentation and Methods for Astrophysics; Sensors
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2201.04507

The Simons Observatory (SO) will detect and map the temperature and polarization of the millimeter-wavelength sky from Cerro Toco, Chile across a range of angular scales, providing rich data sets for cosmological and astrophysical analysis. The SO focal planes will be tiled with compact hexagonal packages, called Universal Focal-plane Modules (UFMs), in which the transition-edge sensor (TES) detectors are coupled to 100 mK microwave-multiplexing electronics. Three different types of dichroic TES detector arrays with bands centered at 30/40, 90/150, and 220/280 GHz will be implemented across the 49 planned UFMs. The 90/150GHz and 220/280 GHz arrays each contain 1,764 TESes, which are read out with two 910x multiplexer circuits. The modules contain a series of densely routed silicon chips, which are packaged together in a controlled electromagnetic environment with robust heat-sinking to 100 mK. Following an overview of the module design, we report on early results from the first 220/280GHz UFM, including detector yield, as well as readout and detector noise levels.