Investigation of electron backscattering on silicon drift detectors for the sterile neutrino search with TRISTAN

• Published in: Journal of instrumentation 2024-12, Vol.19 (12), p.P12009
• Main Authors: Spreng, D., Urban, K., Carminati, M., Edzards, F., Fiorini, C., Lechner, P., Nava, A., Siegmann, D., Wiesinger, C., Mertens, S.
• Format: Article
• Language: English
• Subjects: Beta decay; Dark matter; Detector modelling and simulations I (interaction of radiation with matter, interaction of photons with matter, interaction of hadrons with matter, etc); Drift; Electron back scatter; Energy spectra; Focal plane devices; Hypothetical particles; Interaction of radiation with matter; Large detector systems for particle and astroparticle physics; Neutrinos; Particle decay; Particle physics; Shape effects; Silicon; Solid state detectors; Standard model (particle physics); Tritium
• ISSN: 1748-0221
• DOI: 10.1088/1748-0221/19/12/P12009

Sterile neutrinos are hypothetical particles in the minimalextension of the Standard Model of Particle Physics. They could beviable dark matter candidates if they have a mass in the keVrange. The Karlsruhe tritium neutrino (KATRIN) experiment, extendedwith a silicon drift detector focal plane array (TRISTAN), has thepotential to search for keV-scale sterile neutrinos by measuring thekinematics of the tritium β-decay. The collaboration targetsa sensitivity of 10-6 on the mixing amplitudesin2Θ. For this challenging target, a preciseunderstanding of the detector response is necessary. In this work,we report on the characterization of electron backscattering fromthe detector surface, which is one of the main effects thatinfluence the shape of the observed energy spectrum. Measurementswere performed with a tandem silicon drift detector system and acustom-designed electron source. The measured detector response andbackscattering probability are in good agreement with dedicatedbackscattering simulations using the Geant4 simulationtoolkit.