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Researchers have developed a new high-speed readout system for transition-edge sensors (TES) used in cryogenic experiments searching for neutrinoless double-beta decay. The frequency-domain multiplexed readout system samples detectors at 156 kHz, three orders of magnitude faster than previous systems designed for cosmology applications, while maintaining the superior timing performance of TES detectors (approximately 100 microseconds compared to 1 millisecond for conventional thermistors). The system uses ten superconducting resonators and SQUID technology interfaced with FPGA-based electronics, enabling scalability to thousands of detector channels with minimal thermal load and radioactive contamination.
Why it matters
This advancement enables next-generation neutrinoless double-beta decay experiments to better discriminate background signals from potential rare decay events, which is crucial for detecting this theoretical process that could help explain fundamental physics questions about neutrinos and matter-antimatter asymmetry in the universe. The multiplexed readout design also makes it practical to scale these highly sensitive detectors to the large channel counts needed for future experiments.
arXiv:2601.23106v2 Announce Type: replace-cross
Abstract: The next-generation of cryogenic neutrinoless double-beta decay experiments require increasingly fast readout in order to improve background discrimination. These experiments, operated as cryogenic calorimeters at $sim$10 mK, are usually read out by high-impedance neutron transmutation doped (NTD) thermistors, which provide good energy resolution, but are limited by $sim$1 ms response times. Superconducting detectors, such as transition-edge sensors (TESs) with a time resolution of $sim$100 $mu$s, offer superior timing performance over NTD semiconductor bolometers. To make this technology viable for an application to a thousand or more channels, multiplexed readout is necessary in order to minimize the thermal load and radioactive contamination induced by the readout. Frequency-domain multiplexing readout (fMux) for TESs, previously developed at Berkeley Lab and McGill University, is currently in use for mm-wave telescopes with detector sampling rates in the order of 100 Hz. We demonstrate a new readout system, based on the McGill/Berkeley digital fMux readout, to satisfy the higher bandwidth and noise requirements of the next generation of TES-instrumented cryogenic calorimeters. The new readout samples detectors at 156 kHz, three orders of magnitude faster than its cosmology-oriented predecessor. Each multiplexing readout module comprises ten superconducting resonators in the MHz range and a superconducting quantum interference device (SQUID), interfaced to high-bandwidth field programmable gate array (FPGA)-based electronics for digital signal processing and low-latency feedback.