CCAT: Detector Noise Limited Performance of the RFSoC-based Readout Electronics for mm/sub-mm/far-IR KIDs

TL;DR

This paper presents the development and testing of an RFSoC-based readout system for KID detectors in submillimeter telescopes, achieving noise-limited performance suitable for large-scale astronomical surveys.

Contribution

It introduces a novel RFSoC-based multiplexed readout system for KIDs, demonstrating noise-limited performance in cryogenic conditions for the first time.

Findings

Achieved detector noise limited performance with RFSoC readout.

Validated system operation across multiple cryogenic setups.

Demonstrated suitability for large-scale submillimeter surveys.

Abstract

The Fred Young Submillimeter Telescope (FYST), on Cerro Chajnantor in the Atacama desert of Chile, will conduct wide-field and small deep-field surveys of the sky with more than 100,000 detectors on the Prime-Cam instrument. Kinetic inductance detectors (KIDs) were chosen as the primary sensor technology for their high density focal plane packing. Additionally, they benefit from low cost, ease of fabrication, and simplified cryogenic readout, which are all beneficial for successful deployment at scale. The cryogenic multiplexing complexity is pulled out of the cryostat and is instead pushed into the digital signal processing of the room temperature electronics. Using the Xilinx Radio Frequency System on a Chip (RFSoC), a highly multiplexed KID readout was developed for the first light Prime-Cam and commissioning Mod-Cam instruments. We report on the performance of the RFSoC-based readout with multiple detector arrays in various cryogenic setups. Specifically we demonstrate detector noise limited performance of the RFSoC-based readout under the expected optical loading conditions.