Superconducting Nanowire Single-Photon Detectors for Dark Matter Detection Applications

Abstract

Superconducting Nanowire Single Photon Detectors (SNSPDs) are a leading detector technology for time-correlated single-photon counting from the UV to the near-infrared. Due to their unique combination of low energy thresholds and low intrinsic dark count rates, SNSPDs have become attractive as sensors for emerging low-mass dark matter (DM) detection experiments, where they offer the potential to fill existing technology gaps and enable the exploration of previously unconstrained parameter space. One developing DM detection concept, sensitive to MeV-scale DM electron recoils, uses \textit{n}-type GaAs as a cryogenic scintillating target instrumented with a large-area SNSPD as the sensor for scintillation photons.

This thesis focuses on the development and characterization of SNSPDs with mm\(^2\)-scale active areas for DM applications in general, and specifically for the detection of scintillation light. This work demonstrates the coupling of \textit{n}-type GaAs with SNSPDs, and the design of novel characterization experiments using optical and energy-tagged X-ray excitation to measure the effective light yield and photoluminescence timescales of cryogenic scintillators using SNSPDs. The isotropic nature of scintillation light and the large active areas of the devices studied in this work introduce unique challenges for SNSPD design, nanofabrication, and performance. This thesis provides insights into the current state-of-the art, limitations, and approaches to scaling SNSPDs to cm\(^2\)-scale active areas for future work. The presented findings advance the status of SNSPDs for DM detection and other emerging High-Energy Physics applications.