The CRS: a scalable full-stack control system for Microwave Kinetic Inductance Detectors

TL;DR

The CRS is a scalable, full-stack control system designed for microwave Kinetic Inductance Detectors, capable of managing thousands of KIDs with flexible bandwidth, synchronization, and advanced signal processing for applications in astronomy and quantum computing.

Contribution

This work introduces a modular, scalable control system for KID arrays, with firmware, hardware design, and software supporting large-scale multiplexing and dynamic measurement modes.

Findings

Supports 4,096 KIDs over 2.5 GHz bandwidth

Operates with four RF chains at 1,024x multiplexing

Supports arrays of over 65,000 KIDs in a single subrack

Abstract

The t0.technology Control and Readout System (CRS) is a modular microwave control and readout system for mm-wave and radio astronomy, THz imaging, noise radar, and superconducting qubit control. The configuration discussed in this work implements firmware for readout of microwave Kinetic Inductance Detector (KID) arrays. The CRS can operate 4,096 KIDs over 2.5 GHz of complex bandwidth between 0-10 GHz, typically allocated across four independent RF chains at 1,024x multiplexing and 625 MHz of complex bandwidth each. Every CRS can operate as a standalone unit or collectively within one or more backplane-enabled subracks that distribute power, clocking, and synchronization, scaling to an arbitrary number of channels. Each fully populated subrack supports arrays of more than 65,000 KIDs. The signal processing and control software supports recent innovations in multi-probe measurements and dynamic feedback modes, which are described in (Rouble et al. 2024). The CRS has recently been selected as the new baseline readout system for the proposed South Pole Telescope instrument, SPT-3G+. We present the hardware design, firmware capabilities, open-source control and data acquisition software, and the first laboratory characterization measurements.