SMuK 2023 – wissenschaftliches Programm

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T: Fachverband Teilchenphysik

T 68: Neutrinos, Dark Matter VIII

T 68.2: Vortrag

Mittwoch, 22. März 2023, 16:05–16:20, POT/0006

Observables of the Electrical Potential of the KATRIN Tritium Source from Calibration with a High-Intensity Krypton-83m Source — •Moritz Machatschek for the KATRIN collaboration — Institute for Astroparticle Physics, Karlsruhe Institute of Technology

The KArlsruhe TRItium Neutrino experiment currently provides the best neutrino-mass upper limit of 0.8 eV/c² (90 % C. L.) in the field of direct neutrino-mass measurements. Reaching the target sensitivity of 0.2 eV/c² at 90 % C. L. not only relies on the ongoing data taking, but also the detailed study of systematic measurement uncertainties.

One major uncertainty is linked to the electric potential inside the tritium source. Inhomogeneities of the potential lead to a distortion of the β-spectrum, which needs to be characterized in order to reduce the systematic bias in the neutrino-mass measurement.

To this end we use conversion electrons from ^83mKr as nuclear standard. Traces of gaseous ^83mKr are circulated alongside tritium in the 10 m long source, such that inhomogeneities of the potential are observable as a broadening of the selected mono-energetic ^83mKr lines. In this talk we describe the result of a three-week long ^83mKr campaign carried out in 2021 and its impact on the neutrino-mass determination.

This work is supported by the Helmholtz Association, the Ministry for Education and Research BMBF (05A17PM3, 05A17PX3, 05A17VK2, and 05A17WO3), the Helmholtz Alliance for Astroparticle Physics (HAP), and the Helmholtz Initiative and Networking Fund (W2/W3-118).