Digital frequency multiplexing with sub-Kelvin SQUIDs

2018/07/16 by Lowitz, Amy E., Bender, Amy N., Dobbs, Matthew A. +1
#FOS: Physical sciences #Instrumentation and Methods for Astrophysics (astro-ph.IM)

paper · doi:10.48550/arxiv.1807.05995

Abstract

Digital frequency multiplexing (dfMux) is a readout architecture for transition edge sensor-based detector arrays and is used on telescopes including SPT-3G, POLARBEAR-2, and LiteBIRD. Here, we present recent progress and plans for development of a sub-Kelvin SQUID architecture for digital frequency multiplexed bolometers. This scheme moves the SQUID from the 4 K stage to the 250 mK stage, adjacent to the bolometers. Operating the SQUID on the detector stage may offer lower noise and greater scalability. Electrical performance will be improved as a result of decreased wiring length and reduced parasitics, allowing for higher multiplexing factors and lower bolometer R_normal . These performance improvements will enable ultra-large focal planes for future instruments such as CMB-S4.

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