A D₂O detector for flux normalization of a pion decay-at-rest neutrino source

We report on the technical design and expected performance of a 592 kg heavy-water-Cherenkov detector to measure absolute neutrino flux from pion-decay-at-rest source at Spallation Neutron Source (SNS) Oak Ridge National Laboratory (ORNL). The will be located roughly 20 m SNS target with better than 5% statistical uncertainty in 2 years. This heavy-water serve as first module two-module system ultimately 2–3% both First Target Station planned Second SNS. significantly reduce dominant systematic for cross-section measurements SNS, increasing sensitivity searches new physics.