Dortmund 2021 – scientific programme

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T: Fachverband Teilchenphysik

T 97: Experimental techniques in astroparticle physics IV

T 97.8: Talk

Thursday, March 18, 2021, 17:45–18:00, Tv

The LEGEND Liquid Argon Monitoring Apparatus (LLAMA) — •Mario Schwarz, Patrick Krause, Laszlo Papp, and Stefan Schönert — Physik-Department, Technische Universität München, Garching

Large volume liquid argon (LAr) scintillation detectors require a precise assessment of key optical parameters for rigid signal predictions and proper data interpretation. Considering neutrinoless double beta decay experiments, both the state-of-the-art GERDA experiment as well as the next-generation LEGEND 200 and 1000 detectors use LAr scintillation light read-out as part of their active veto system. Modeling the LAr veto efficiency requires knowledge of the optical parameters in LAr, which depend on the actual impurity concentrations in the liquid. To this end, a dedicated setup has been designed for in-situ measurements of the light yield, the triplet lifetime and the attenuation length valid for the 128 nm primary emission wavelength. The setup will monitor the LAr in the LEGEND 200 cryostat, where it resides permanently. Ahead of its successful installation in the cryostat, in the scope of a one-time measurement campaign, LLAMA measured optical properties of the LAr in GERDA.

An overview of LLAMA and preliminary results of the measurements in the GERDA cryostat are presented as well as data obtained at TUM. The work has been supported in part by the German Federal Ministry for Education and Research (BMBF) Verbundforschung.