Data Acquisition for the Nab Detector

The purpose of the Nab experiment is a precise measurement of the electron-neutrino correlation coefficient `a' and the Fierz interference coefficient `b' in neutron beta decay, with the goal of testing the unitarity of the Cabibbo-Kobayashi-Maskawa matrix and searching for new physics, such as weak scalar and tensor interactions. Two detectors are used to collect electron and proton signals from the neutron decay processes. Achieving a target uncertainty of Δa/|a| = 0.001 in `a' requires understanding the time difference between events on both detector systems with a systematic bias of 300 ps or better. A novel data acquisition system with advanced triggering capabilities based on National Instruments hardware and software has been developed to achieve this timing resolution. I will describe the triggering, synchronization, and event selection mechanisms of the data acquisition system and show how we meet the specification.