Fluorescence of pyrene-doped polystyrene films from room temperature down to 4 K for wavelength-shifting applications

Abstract

In liquid argon-based particle detectors, slow wavelength shifters (WLSs) could be used alongside the common, nanosecond scale, WLS tetraphenyl butadiene (TPB) for background mitigation purposes. At room temperature, pyrene has a moderate fluorescence light yield (LY) and a time constant of the order of hundreds of nanoseconds. In this work, four pyrene-doped polystyrene films with various purities and concentrations were characterized in terms of LY and decay time constants in a range of temperature between 4 K and 300 K under ultraviolet excitation. These films were found to have a LY between 35 and 50% of that of evaporated TPB. All light yields increase when cooling down, while the decays slow down. At room temperature, we observed that pyrene purity is strongly correlated with emission lifetime: highest obtainable purity samples were dominated by decays with emission time constants of $\sim$ 250-280 ns, and lower purity samples were dominated by an $\sim$ 80 ns component. One sample was investigated further to better understand the monomer and excimer emissions of pyrene. The excimer-over-monomer intensity ratio decreases when the temperature goes down, with the monomer emission dominating below $\sim$ 87 K.

arXiv comment22 pages, 14 figures

References in corpus (11)

• Array Programming with NumPy
• The Large Underground Xenon (LUX) Experiment
• The XENON1T Dark Matter Experiment
• Results from the first use of low radioactivity argon in a dark matter search
• Search for dark matter with a 231-day exposure of liquid argon using DEAP-3600 at SNOLAB
• NEXO: Neutrinoless double beta decay search beyond $10^{28}$ year half-life sensitivity
• Slow Fluors for Effective Separation of Cherenkov Light in Liquid Scintillators
• Wavelength shifters for applications in liquid argon detectors
• Search for inelastic WIMP nucleus scattering on ${}^{129}$Xe in data from the XMASS-I experiment
• Temperature-dependent fluorescence emission spectra of acrylic (PMMA) and tetraphenyl butadiene (TPB) excited with UV light
• Development and characterization of a slow wavelength shifting coating for background rejection in liquid argon detectors

Cited by in corpus (2)

• Ultraviolet-induced fluorescence of poly(methyl methacrylate) compared to 1,1,4,4-tetraphenyl-1,3-butadiene down to 4 K
• Development and characterization of a slow wavelength shifting coating for background rejection in liquid argon detectors