Coherent CAPTAIN-Mills: Measuring Low-Energy Neutrino Cross Sections at Los Alamos Neutron Science Center*

Core-collapse supernovae (SN) release 99% of their gravitational binding energy in neutrinos with energies of a few tens-of-MeV over a timescale of a few tens-of-seconds. The flavor composition, energy spectrum and time structure of the neutrino burst in a SN explosion provide information about the supernova properties, including its core-collapse, explosion and neutron star cooling mechanism. Coherent CAPTAIN-Mills (CCM) is a Liquid Argon (LAr) detector located at the Lujan Center at the Los Alamos Neutron Science Center which is a prolific source of neutrinos up to 50 MeV from stopped pion and muon decay. By instrumenting CCM with photo-multiplier tubes (PMTs) and fast electronics, a significant measurement of low-energy neutrino scattering cross sections can be performed. We propose to use the CCM detector to measure the ν_e and ν_μ nuclear cross sections on liquid argon with an uncertainty of roughly 10%, focusing on the supernova energy range. This poster discusses the importance of the measurements of low-energy neutrino cross sections for the observation of supernovae explosions, as well as the PMT background rate and energy distribution, status of the detector and Fall commissioning run.