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T: Fachverband Teilchenphysik
T 43: Neutrino physics without accelerators II
T 43.4: Vortrag
Dienstag, 16. März 2021, 16:45–17:00, Tr
Precision measurement of the energy loss of e−-T2 scattering in the source of KATRIN — •Lutz Schimpf for the KATRIN collaboration — ETP, Karlsruhe Institute of Technology (KIT)
The Karlsruhe Tritium Neutrino experiment (KATRIN) is targeted to measure the effective neutrino mass m(νe) with a sensitivity of 0.2 eV at 90 % CL. In order to determine the neutrino mass, an integrated β-decay spectrum close to the endpoint is measured and a fit to the data comprising m(νe) as a free parameter is performed. A number of systematic effects on the measured spectrum need to be taken into account in the spectral analysis. One of these is the energy loss of the β-electrons from inelastic scatterings with the source gas. The probability distribution of the energy losses of 18.6 keV electrons scattering off molecular tritium can be determined in-situ with KATRIN by using a pulsed monoenergetic source of photoelectrons, allowing for time-of-flight spectroscopy. The measurement is analysed by fitting a newly developed, semi-empirical energy-loss model to a combined data set of integral and differential spectra. With this measurement and analysis technique, an analytical description of the energy loss function with unprecedented precision is obtained. In this contribution, the latest analysis results will be presented and discussed in the context of the neutrino-mass systematics budget of KATRIN.
This work is supported by the Helmholtz Association (HGF), the Ministry for Education and Research BMBF (05A17PM3, 05A17PX3, 05A17VK2, and 05A17WO3), and the Helmholtz Alliance for Astroparticle Physics (HAP).