Signal Characterization for Phase-III of the BeEST Experiment using a Triggerless Digital DAQ

The BeEST experiment uses Superconducting Tunnel Junction (STJ) detectors to measure the daughter recoil energy following the EC decay of 7Be to search for heavy neutrino mass states. Past limit-setting results from the experiment used a list-mode ADC with a hardware trapezoidal filter to trigger the pulses from the STJ array. To improve our signal analysis capabilities, we have constructed a continuously sampling data acquisition system which allows for advanced offline characterization of events using pulse shape and timing information. This talk will demonstrate the advantages to the Phase-III BeEST experimental program enabled by continuous acquisition, and present performance metrics for the new system as well as the performance of the Phase-III BeEST detector array.