Impact of ADC non-linearities on the sensitivity to sterile keV neutrinos with a KATRIN-like experiment

ADC non-linearities are a major systematic effect in the search for keV-scale sterile neutrinos with tritium beta-decay experiments like KATRIN. They can significantly distort the spectral shape and thereby obscure the tiny kink-like signature of a sterile neutrino. In this work we demonstrate various mitigation techniques to reduce the impact of ADC non-linearities on the tritium beta-decay spectrum to a level of < ppm. The best results are achieved with a multi-pixel (>= 10(4) pixels) detector using full waveform digitization. In this case, active-to-sterile mixing angles of the order of sin(2)theta = 10(-7) would be accessible from the viewpoint of ADC non-linearities. With purely peak-sensing ADCs a comparable sensitivity could be reached with highly linear ADCs, sufficient non linearity corrections or by increasing the number of pixels to >= 10(5).