Performance of a Silicon SuperCDMS HVeV Detector Operated Underground at NEXUS

The Super Cryogenic Dark Matter Search (SuperCDMS) uses cryogenically cooled silicon and germanium calorimeters to search for dark matter interactions. In recent years, SuperCDMS HVeV (high voltage with eV resolution) detectors have enabled searches for sub-GeV dark matter candidates, including nucleons- and electron-recoiling dark matter, dark photons, and axion-like particles. HVeV detectors are equipped with transition-edge sensors (TESs) connected to superconducting aluminum films to achieve high-resolution athermal phonon sensing. The excellent phonon resolution enables single-charge sensitivity by applying an electric field across the crystal to achieve phonon-based charge amplification via the Neganov-Trofimov-Luke (NTL) effect. In this talk, I will present the performance of a 1-gram silicon HVeV detector operated at the NEXUS (Northwestern EXperimental Underground Site) facility hosted at Fermilab (Batavia, IL).