Köln 2025 – scientific programme
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HK: Fachverband Physik der Hadronen und Kerne
HK 23: Poster
HK 23.41: Poster
Tuesday, March 11, 2025, 17:30–19:00, Foyer Physik
A side access system to the KATRIN beamline — •Kyrill Blümer, Christian Gönner, Kevin Gauda, Volker Hannen, Hans-Werner Ortjohann, Sonja Schneidewind, Leo Weßeler, and Christian Weinheimer for the KATRIN collaboration — Universität Münster, Institut für Kernphysik
The KATRIN experiment aims to measure the neutrino mass via spectroscopy of the tritium β-decay. An upper limit mν< 0.45 eV/c2 (90% C.L.) was published in 2024 (arXiv:2406.13516). Despite implementation of efficient countermeasures, an elevated experimental background is observed, which needs to be reduced to reach the design sensitivity. Radioactive decays in the stainless steel vessel of the main spectrometer produce highly-excited Rydberg or autoionizing states of atoms in the spectrometer volume, which release low-energetic electrons. These are energetically indistinguishable from β-electrons at the detector. Their angular distribution, however, is significantly sharper. The "active Transverse Energy Filter" (aTEF) concept was invented to reduce this background by discrimination of electrons in a large magnetic field based on their pitch angle (EPJ C 82 (2022) 922) and successfully tested as a modification of commercial Si-PIN diodes. The presented side-access system to the KATRIN beamline allows in-situ tests of the aTEF-prototypes and can provide direct measurements of the angular distribution of the KATRIN background electrons. Further, it can serve as a platform for calibration tools for the so-called TRISTAN-upgrade of the detector. This work is supported by BMBF ErUM-Pro 05A23PMA.
Keywords: KATRIN; silicon detectors; neutrino mass; background reduction