Antineutrino sensitivity at THEIA

This poster will present the sensitivity towards the detection of low-energy antineutrinos of the Theia detector. For the purposes of this study, we consider one of the possible proposed designs, a 25-ktonne Theia-25 detector filled with a water-based liquid scintillator (WbLS) placed at Sanford Underground Research Facility (SURF). Currently, only two detectors in the world have measured geoneutrinos, antineutrinos originating from the radioactive decays of long-lived isotopes naturally present in the crust and mantle. Due to variations of the crust thickness, the geoneutrino flux measurements at different geographical locations can help separate a much less position-dependent mantle contribution. We demonstrate Theia’s sensitivity to measure the antineutrino fluxes via Inverse-Beta Decay (IBD) interactions with unprecedented precisions for geo- and reactor neutrinos, respectively, in only one year. We also demonstrate the sensitivity towards the Th/U ratio in geoneutrino flux.