Preparation and characterization of polystyrene-based plastic scintillators as a self-vetoing structural material

Abstract

The liquid argon (LAr) detector has garnered significant interest in recent experiments focusing on dark matter and neutrinoless double-beta decay searches. However, the wavelength shifting and light collection present persistent technical challenges for the liquid argon (LAr) detector. In this work, a novel plastic scintillator material was developed and optimized to enhance the light collection efficiency of LAr detectors. The plastic scintillator was prepared via thermal polymerization, utilizing styrene as the matrix doped with TPB (1,1,4,4-tetraphenyl-1,3-butadiene). A mass fraction of 1% of TPB-PS has been identified as the optimal concentration, emitting the strongest blue fluorescence with a quantum yield of 99.89%. The fluorescence emission spectrum of the new material peaks at 440 nm, which aligns with the best quantum efficiency of conventional photoelectron converter devices. The light yield of the 1% TPB-PS is 73.98% relative to the value of the standard sample EJ-200. Its decay time is 2.75 ns approximately. Mechanical tests present the developed TPB-PS material can be used as an active structure material for LAr detectors in next-generation experiments. Furthermore, the TPB-PS material can be prepared into wavelength-shifting (WLS) optical fiber, which can be coupled with silicon photomultipliers (SiPMs) to enhance the light collection efficiency of LAr detectors, improving background rejection and energy resolution.