Sensitivity Study of a Scintillating Active Transverse Energy Filter for Background Suppression at the KATRIN Experiment

The Karlsruhe Tritium Neutrino (KATRIN) experiment aims to determine the mass of the electron antineutrino by precise measurement of the energy spectrum of β-electrons from tritium decay using a MAC-E-Filter setup. After a total measurement time of 1000 days in 2025, a final sensitivity better than 0.3 eV/c2 (90 % C.L.) is expected.

At the moment, one sensitivity limiting factor is the spectrometer background which consists of electrons that are generated in the mainspectrometer volume. Due to their small initial energy, the background electrons have a different angular distribution than the signal electrons at the point of detection.

A scintillating structure acting as an angular selective detector (scint-aTEF) has potential to discriminate between β- and background electrons. This talk will discuss the concept of the scint-aTEF and its expected impact on background reduction and neutrino mass sensitivity, based on simulations.
This work is supported by the Helmholtz Association and by the Ministry for Education and Research BMBF (grant numbers 05A23PMA, 05A23PX2, 05A23VK2, and 05A23WO6).