Apr 13 – 16, 2026
KIT Campus South
Europe/Berlin timezone

Electron backscattering at the Focal Plane Detector (FPD) of KATRIN

Apr 13, 2026, 5:07 PM
2m
Gaede Foyer (KIT Campus South)

Gaede Foyer

KIT Campus South

2nd floor (in front of Gaede-Lecture theater) Physikflachbau Building 30.22 Engesserstraße 7 76131 Karlsruhe
Poster Posters

Speaker

Philipp Lingnau (KIT)

Description

The KATRIN experiment has put the most stringent model-independent upper limit on the electron antineutrino mass. The goal is to limit it to < 0.3 eV. To achieve this, a large amount of tritium beta-electrons need to be analyzed using a MAC-E-filter type spectrometer.

One systematic effect on the neutrino mass measurement is the detector backscattering. We are using simulations describing the electron scattering in the silicon waver to estimate the effect on the neutrino mass to be $2\cdot 10^{-3}\, \mathrm{eV}^2$. In order to verify this, we performed an in-situ measurement using time-of-flight spectroscopy. With it, the electron energy loss due to plasmon excitations inside the detector can be resolved. This measurement can help to better understand the FPD response model, which allows the ab initio calculation of several systematic effects on the neutrino mass, enabling their inclusion in the analysis, and thereby minimizing their impact on the neutrino mass uncertainty.

I will present the analysis of the measurement, featuring various improvements, including a rigorous investigation of the impact of fluctuations of the electrical potentials, improved electric and magnetic field simulations using Kassiopeia, as well as more in-depth time-of-flight simulations.

In the future, this measurement principle and the analysis framework can be adapted for the TRISTAN phase of KATRIN, where understanding the escape spectrum from backscattered electrons is of greater importance than for KATRIN.

Collaboration or Other Affiliation KATRIN

Author

Philipp Lingnau (KIT)

Co-authors

Dr Alexander Marsteller (Karlsruhe Institute of Technology) Caroline Rodenbeck (Karlsruher Institut für Technologie (KIT), IAP-TLK) Sanshiro Enomoto (University of Washington)

Presentation materials