Quantifying Signal Readout Non-Linearity for the BeEST Experiment

The BeEST experiment uses superconducting tunnel junction (STJ) radiation detectors to investigate the electron-capture decay of ⁷Be to search for sub-MeV neutrino mass states. We have developed a LabView code for an NI PXIe-5423 arbitrary waveform generator to simulate STJ signals with an amplitude distribution expected as the output of this experiment. This code is used to quantify systematic uncertainties in the readout chain of the BeEST experiment such as non-linearities in the analog-to-digital converters or channel-to-channel variations. In addition, arbitrary sterile neutrino mixing can be injected into the BeEST spectrum to test the sensitivity of our analysis code to various sterile neutrino masses and mixing angles.