The Coherent Elastic Neutrino Nucleus Scattering (CENNS) Experiment at Fermilab
Description
Low-energy neutrinos (E ≤ 50 MeV) have a wavelength that is larger than the target nuclei. These neutrinos can engage in coherent elastic neutrino-nucleus scattering with very low neutral current momentum transfer. At these energies, the coherent scattering cross section dominates, but because it deposits very little energy, low detection thresholds are required. Dark matter searches have led to detector technologies that are capable of the first direct measurement with accelerator and reactor neutrino sources. Coherent scattering measurements can help to understand supernova dynamics and detection, probe weak nuclear form factors at low Q2, measure the weak mixing angle, and search for non-standard interactions and neutrino magnetic moments. Furthermore, coherent scattering of atmospheric and solar neutrinos will be an irreducible background for dark matter searches with 10-ton detectors. The CENNS collaboration proposes a 1-ton, single-phase, liquid argon detector to measure coherent neutrino scattering near the booster neutrino beam (BNB) at Fermilab. By placing the detector near the beam target in a far off-axis position, low-energy neutrinos are produced with an energy spectrum that is similar to a stopped pion source. The proximity to the BNB introduces a background of beam-correlated neutrons whose elastic scatters are indistinguishable from the neutrino signal. The Indiana-built SciBath-768 detector was deployed 20 m from the BNB beam target to measure the flux of beam-correlated neutrons, and these results are currently guiding the design of a fast neutron shield. In this talk, I will describe the physics motivation for CENNS, the proposed detector, the results of the SciBath beam-correlated neutron background measurement, and the ongoing shielding studies.