Simulation Studies of Nuclear Recoils Resulting from Coherent Elastic Neutrino-Nucleus Scattering in Gaseous Argon

Neutrinos are light weakly interacting particles that play a crucial role in how the universe formed and how it operates today. One way in which neutrinos can interact with matter is called Coherent Elastic Neutrino-Nucleus Scattering (CEvNS), in which a neutrino interacts with the entire nucleus of an atom. The theoretically clean nature of this interaction makes it a good tool to search for physics beyond the standard model. The principal challenge in detecting CEvNS arises from the low energy nuclear recoils which have energies of less than a few hundred keV for neutrinos produced from stopped pion sources such as the Spallation Neutron Source at Oak Ridge National Laboratory. The ability to track the directionality of NRs has a wide range of applications for measurements of CEvNS, incluring measuring the incoming neutrino on an event-by-event basis as well as improving background rejection in WIMP Dark Matter searches. In this work we present simulations that study the intrinsic resolution for NR directionality measurements in the 10-100 keV range. We find that when propagating through argon, NRs experience deflections of approximately 30 degrees due to the stochastic nature of scattering and energy loss. Similar studies of the energy resolution suggest an intrinsic smearing of 30-40% in the ionization charge signal component. These studies will help guide detector design and hardware optimization.This work leverages the Stopping and Range of Ions in Matter (SRIM) simulation, and is a first step towards the design and realization of a gaseous detector capable of observing NR directionality in a stopped pion neutrino beam.