The Simons Observatory microwave SQUID multiplexing detector module design

Abstract

Advances in cosmic microwave background (CMB) science depend on increasing the number of sensitive detectors observing the sky. New instruments deploy large arrays of superconducting transition-edge sensor (TES) bolometers tiled densely into ever larger focal planes. High multiplexing factors reduce the thermal loading on the cryogenic receivers and simplify their design. We present the design of focal-plane modules with an order of magnitude higher multiplexing factor than has previously been achieved with TES bolometers. We focus on the novel cold readout component, which employs microwave SQUID multiplexing ($\mu$mux). Simons Observatory will use 49 modules containing 60,000 bolometers to make exquisitely sensitive measurements of the CMB. We validate the focal-plane module design, presenting measurements of the readout component with and without a prototype detector array of 1728 polarization-sensitive bolometers coupled to feedhorns. The readout component achieves a $95\%$ yield and a 910 multiplexing factor. The median white noise of each readout channel is 65 $pA/\sqrt{\mathrm{Hz}}$. This impacts the projected SO mapping speed by $<8\%$, which is less than is assumed in the sensitivity projections. The results validate the full functionality of the module. We discuss the measured performance in the context of SO science requirements, which are exceeded.

arXiv commentAccepted to The Astrophysical Journal

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Cited by in corpus (21)

• SLAC Microresonator RF (SMuRF) Electronics: A tone-tracking readout system for superconducting microwave resonator arrays
• The Simons Observatory 220 and 280 GHz Focal-Plane Module: Design and Initial Characterization
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• The Simons Observatory: A fully remote controlled calibration system with a sparse wire grid for cosmic microwave background telescopes
• The Simons Observatory: Characterizing the Large Aperture Telescope Receiver with Radio Holography
• Improved microwave SQUID multiplexer readout using a kinetic-inductance traveling-wave parametric amplifier
• The Simons Observatory: Development and Optical Evaluation of Achromatic Half-Wave Plates
• Crosstalk effects in microwave SQUID multiplexed TES bolometer readout
• Simons Observatory Focal-Plane Module: In-lab Testing and Characterization Program
• Demonstration of a 1820 channel multiplexer for transition-edge sensor bolometers
• The Simons Observatory: Studies of Detector Yield and Readout Noise From the First Large-Scale Deployment of Microwave Multiplexing at the Large Aperture Telescope
• Material properties of a low contraction and resistivity silicon-aluminum composite for cryogenic detectors
• The Simons Observatory: Design and Measured Performance of a Carbon Fiber Strut for a Cryogenic Truss
• The Simons Observatory: Alarms and Detector Quality Monitoring
• The Simons Observatory: A Minimum-Cost Matching Algorithm for Pairing Measured Resonances with Designed Detectors
• The Simons Observatory: Differentiating Thermal and Optical Effects in Superconducting Transition-Edge Sensing Bolometers
• Readout noise of digital frequency multiplexed TES detectors for CUPID
• The Simons Observatory: Studies of Phase Drift in RF Transmission Lines from the First Large-Scale Deployment of Microwave Frequency Multiplexing for Cosmology
• High-bandwidth frequency domain multiplexed readout of transition-edge sensors for neutrinoless double beta decay searches
• The Simons Observatory: Design, Integration, and Current Status of Small Aperture Telescopes
• CCAT-prime: Characterization of the First 280 GHz MKID Array for Prime-Cam