  Sterile neutrinos are a minimal extension of the Standard Model of Particle
Physics. A promising model-independent way to search for sterile neutrinos is
via high-precision beta spectroscopy. The Karlsruhe Tritium Neutrino (KATRIN)
experiment, equipped with a novel multi-pixel silicon drift detector focal
plane array and read-out system, named the TRISTAN detector, has the potential
to supersede the sensitivity of previous laboratory-based searches. In this
work we present the characterization of the first silicon drift detector
prototypes with electrons and we investigate the impact of uncertainties of the
detector's response to electrons on the final sterile neutrino sensitivity.
