Background Neutron Studies for Coherent Elastic Neutrino-Nucleus Scattering Measurements at the SNS

The COHERENT collaboration has proposed to measure coherent, elastic neutrino-nucleus scattering (CE$\nu $NS) cross sections on several nuclear targets using neutrinos produced at the Spallation Neutron Source (SNS) located at the Oak Ridge National Laboratory. The largest background of concern arises from beam-induced, fast neutrons that can mimic a nuclear recoil signal event in the detector. Multiple technologies of neutron detection have been employed at prospective experiment sites at the SNS. Analysis of these data have produced a consistent picture of the backgrounds expected for a CE$\nu $NS measurement. These background studies show that at suitable locations, the fast neutrons of concern arrive mainly in the prompt 1.3 $\mu $s window and the neutrons in the delayed window are primarily of lower energies that are relatively easier to shield.