Speaker
Description
Low threshold cryogenic detectors have achieved unprecedented sensitivity through advances in superconducting materials, device architecture, and experimental techniques. Leading experiments such as TESSERACT aim to use athermal phonon sensitive devices to place new constraints on low-mass dark matter with a variety of targets. However, all cryogenic detectors observe a sharp rise in low-energy event rates extending to threshold, along with excess parasitic shot noise that degrades their fundamental resolution and performance. This phenomenon, commonly referred to as the “low-energy excess” (LEE), has emerged as a major limitation for next-generation superconducting technologies. In this talk, I will present recent work on understanding this background and the dynamics of athermal phonon sensors. I will also describe a multidisciplinary R&D effort aimed at systematically studying fabrication techniques, material science and correlating them with measured device response.