Superconducting transition-edge sensors (TESs) are a type of quantum sensor known for its high single-photon detection efficiency and low background. This makes them ideal for particle physics experiments searching for rare events. In this work, we present a comprehensive characterization of the background in optical TESs, distinguishing three types of events: electrical-noise, high-energy, and photonlike events. We introduce computational methods to automate the classification of events. For the first time, we experimentally verify and simulate the source of the high-energy events. We also isolate the photonlike events, the expected signal in dielectric haloscopes searching for dark matter dark photons, and achieve a record-low photonlike dark-count rate of 3.6×10−4 Hz in the 0.8-3.2 eV energy range.
@article{arxiv.2402.03073,
title = {Dark counts in optical superconducting transition-edge sensors for rare-event searches},
author = {Laura Manenti and Carlo Pepe and Isaac Sarnoff and Tengiz Ibrayev and Panagiotis Oikonomou and Artem Knyazev and Eugenio Monticone and Hobey Garrone and Fiona Alder and Osama Fawwaz and Alexander J. Millar and Knut Dundas Morå and Hamad Shams and Francesco Arneodo and Mauro Rajteri},
journal= {arXiv preprint arXiv:2402.03073},
year = {2025}
}