Ponente
Descripción
Liquid argon (LAr) detectors are deployed in rare event searches such as dark matter searches, neutrino oscillation experiments, and experiments searching for neutrinoless double beta decay. These detectors rely on wavelength shifting (WLS) materials to convert argon scintillation light (at 128 nm) to visible wavelengths, enabling efficient light collection with reflectors and detection by conventional photosensors. Tetraphenyl butadiene (TPB) is commonly used as a WLS material, but its scalability for large detectors is hindered by the requirement for vacuum evaporation to achieve high light yield. To address this challenge, we present the results from a comprehensive survey of WLS reflectors based on several reflector types, including 3M™ Enhanced Specular Reflector, Tetratex®, and Tyvek®, as well as various production grades and surface finishes of commercially available Teonex® polyethylene naphthalate (PEN) films, a potential scalable alternative to TPB. For characterization, three different facilities were used: a cryogenic VUV spectrometer at TUM, LArS – a kg-scale LAr setup instrumented with a VUV-sensitive PMT at UZH, and a 2-tonne LAr setup at CERN.
