Precision Measurement of Coherent Elastic Neutrino-Nucleus Scattering from Reactor Antineutrinos

University Of Chicago, Chicago IL

Investigators

Abstract

Coherent Elastic Neutrino-Nucleus Scattering (CEvNS) is a recently demonstrated mode of interaction for neutrinos. Possible technological applications include nuclear reactor monitoring. CEvNS also provides a new sensitive window into the study of neutrino properties and nuclear structure. This award will allow the installation of a CEvNS-sensitive detector in the vicinity of a power nuclear reactor (an intense source of low-energy neutrinos), observing for the first time the correlation between CEvNS signals and reactor power. A comparison of the signals detected with expectations from theoretical models will constrain several neutrino properties presently not well-known. Deviations from the predictions of the Standard Model of particle interactions, if observed, will inform new models capable of superseding this current theoretical framework. The award will also facilitate detector calibrations using neutron beams capable of mimicking CEvNS signals: these studies are necessary to interpret the data obtained during reactor exposure. Support for a graduate student towards Ph.D. completion will be provided, with an emphasis on the recruitment of Hispanic minorities. Previous NSF support (PHY-1506357 and PHY-1812702) allowed the PI and his team to perform the first measurement of CEvNS at a spallation source, and to obtain suggestive evidence for this process from reactor antineutrinos using an ultra-low noise, large mass germanium detector in close proximity to the core of the Dresden-II nuclear reactor. This award will continue this effort at one of the underground tendon galleries of the Braidwood Generating Station. This location will provide an improvement in signal-to-background ratio from the presently obtained 1/4 to > 20, generating in the process a high-quality precision measurement of CEνNS, independent of background model assumptions. This will maximize returns on the effort already made in detector development and analysis tools. Additionally, a new measurement of the sub-keV quenching factor for nuclear recoils in germanium will be performed at the Ohio State University research rector, profiting from past experience at that facility. The combination of these two measurements is expected to have a large impact on multiple aspects of neutrino phenomenology. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.