Karlsruhe 2024 – scientific programme

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T: Fachverband Teilchenphysik

T 6: Methods in astroparticle physics 1

T 6.4: Talk

Monday, March 4, 2024, 16:45–17:00, Geb. 20.30: 2.067

⁴²K mitigation studies in liquid argon for LEGEND-1000 — •Christoph Vogl¹, Viacheslav Belov¹, Tommaso Comellato¹, Maximilian Goldbrunner¹, Konstantin Gusev¹, Brennan Hackett², Patrick Krause¹, Niko Lay¹, Andreas Leonhardt¹, Béla Majorovits², Susanne Mertens¹, Moritz Neuberger¹, Nadezda Rumyantseva¹, Mario Schwarz¹, Stefan Schönert¹, and Michael Willers¹ — ¹Technical University of Munich, TUM School of Natural Sciences, Department of Physics, James-Franck-Str. 1, 85748 Garching, Germany — ²Max Planck Institute for Physics, Boltzmannstr. 8, 85748 Garching, Germany

The Legend experiment searches for neutrinoless double beta decay (0νββ) of ⁷⁶Ge using high-purity germanium detectors (HPGe). To reduce background sources at the decay’s Q-value (Q_ββ = 2.039 MeV), the detectors are deployed deep underground in an instrumented liquid argon (LAr) volume. However, commercially available LAr contains the cosmogenically activated isotope ⁴²Ar, whose daughter nucleus ⁴²K is a beta emitter (Q_β = 3.5 MeV). Beta particles can produce events in the region of interest, mimicking 0νββ events. Here, we present measurements on ⁴²K suppression conducted in the LAr cryostat SCARF at TU-Munich. We explore analysis of the event topology in germanium detectors, enclosure of the detectors inside an optically active barrier made of polyethylene naphthalate (PEN), and read-out of the scintillation light produced by LAr and PEN. This research is supported by the DFG through the Excellence Cluster ORIGINS EXC 2094-390783311 and the SFB1258.

Keywords: Ar-42 K-42 mitigation; pulse shape discrimination; PEN enclosure; liquid argon; high purity germanium detectors