Workshop on "Determination of the Absolute Electron (Anti-)Neutrino Mass"

Measurement of the Electron Backscattering on the KATRIN Rear Wall

Apr 13, 2026, 5:33 PM

2m

Gaede Foyer (KIT Campus South)

Poster Posters

Speakers

Justus Beisenkötter (Uni Münster) Neven Kovac (Institute for Astroparticle Physics, Karlsruhe Institute of Technology)Dr Rudolf Sack (Karlsruhe Institut für Technologie)

Description

Currently, the tightest constraints on the absolute scale of neutrino mass from a direct, model-independent approach, are obtained by the KATRIN experiment, giving an upper limit on the mass of the electron anti-neutrino of 0.45 eV (https://doi.org/10.48550/arXiv.2406.13516), with final projected sensitivity below 0.3 eV.
Reaching these ambitious goals requires proper treatment of all systematic effects, with the scattering related systematics currently dominating the systematics budget. In particular, backscattering of electrons on the gold-coated surface of the KATRIN rear wall results in an additional spectrum, shifted in energy due to energy loss of electrons scattering on gold and tritium gas molecules. If unaccounted for, this systematic effects would bias the neutrino mass and therefore needs to be quantified and taken into account in the final analysis.
With this poster, we will discuss the proposed measurements to quantify the backscattering ratio and show the results of our first measurement campaign.