PMT test stand simulations of first scintillator prototypes towards active Transverse Energy Filter

The Karlsruhe Tritium Neutrino (KATRIN) experiment has the goal of determining the neutrino mass scale with a sensitivity of 0.2 eV/c2 (90%C.L.). One of the most important factors limiting the measurement is the background, originating from the main spectrometer which consists of mostly low energy electrons. These electrons are accelerated by the retarding potential and thus possess low transverse energy, resulting primarily in small angles relative to the guiding magnetic field. Therefore, a detector that allows angular sensitivity could greatly improve the sensitivity of the KATRIN experiment.
The concept of an active Transverse Energy Filter (aTEF) has been proposed (Eur. Phys. J. C 82 (2022) 922) which could use micro-structures to develop such an angular sensitive detector. For this purpose, one of two designs being considered consists of a plastic scintillator that is read out via CMOS single-photon avalanche diodes (SPADs). In this presentation, we discuss our first investigation of scintillator prototypes for 2-photon lithography using Geant4 based simulations and measurements with a photomultiplier setup.
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).