Dortmund 2021 – wissenschaftliches Programm

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T: Fachverband Teilchenphysik

T 97: Experimental techniques in astroparticle physics IV

T 97.1: Vortrag

Donnerstag, 18. März 2021, 16:00–16:15, Tv

Characterization of Wavelength Shifters for Rare-Event Search Experiments at Low Temperatures — •Andreas Leonhardt¹, Gabriela R. Araujo², Patrick Krause¹, Laszlo Papp¹, Tina R. Pollmann³, Stefan Schönert¹, and Andreas Ulrich¹ — ¹Physik Department, Technische Universität München, Garching, Germany — ²Physik-Institut, Universität Zürich, Zurich, Switzerland — ³Nikhef National Institute for Subatomic Physic, University of Amsterdam, Amsterdam, Netherlands

Rare-event search experiments commonly use liquid argon (LAr) as target or instrumented shielding medium. Particle interactions in LAr produce vacuum-ultraviolet (VUV) light flashes with a peak at 128 nm. To enable commercially available photodetectors to detect the scintillation light, it has to be shifted to longer wavelengths. The characterization of wavelength shifting materials is difficult due to the low LAr scintillation wavelength that requires VUV optics in vacuum, and due to the low temperatures the sample must have so that the results are relevant to operation in LAr. We present the wavelength-shifting efficiencies of common wavelength-shifters measured at 128 nm excitation, and the custom fluorometer built to make these measurements. The fluorometer consists of a high-intensity deuterium light source coupled to a VUV monochromator and vacuum-tight sample chamber. Both the wavelength-integrated and wavelength-resolved fluorescence yield can be measured. We also describe an ongoing upgrade of the setup that will enable the samples to be cooled to LAr temperature.