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arXiv · 2406.13156

Development of RFSoC-based direct sampling highly multiplexed microwave SQUID readout for future CMB and submillimeter surveys

Chao Liu·Zeeshan Ahmed·Shawn W. Henderson·Ryan Herbst·Larry Ruckman·Thomas Satterthwaite
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Abstract

The SLAC Microresonator Radio Frequency (SMuRF) electronics is being deployed as the readout for the Cosmic Microwave Background (CMB) telescopes of the Simons Observatory (SO). A Radio Frequency System-on-Chip (RFSoC) based readout of microwave frequency resonator based cryogenic sensors is under development at SLAC as an upgrade path for SMuRF with simplified RF hardware, a more compact footprint, and lower total power consumption. The high-speed integrated data converters and digital data path in RFSoC enable direct RF sampling without analog up and down conversion for RF frequencies up to 6 GHz. A comprehensive optimization and characterization study has been performed for direct RF sampling for microwave SQUID multiplexers, which covers noise level, RF dynamic range, and linearity using a prototype implementation. The SMuRF firmware, including the implementation of closed-loop tone tracking, has been ported to the RFSoC platform and interfaced with the quadrature mixers for digital up and down conversion in the data converter data path to realize a full microwave SQUID multiplexer readout. In this paper, a selection of the performance characterization results of direct RF sampling for microwave SQUID multiplexer readout will be summarized and compared with science-driven requirements. Preliminary results demonstrating the read out of cryogenic sensors using the prototype system will also be presented here. We anticipate our new RFSoC-based SMuRF system will be an enabling readout for on-going and future experiments in astronomy and cosmology, which rely on large arrays of cryogenic sensors to achieve their science goals.

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Chao Liu, Zeeshan Ahmed, Shawn W. Henderson, Ryan Herbst, Larry Ruckman, Thomas Satterthwaite. 2024-06-19. Development of RFSoC-based direct sampling highly multiplexed microwave SQUID readout for future CMB and submillimeter surveys. https://arxiv.org/abs/2406.13156

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