Characterization of detection efficiency uncertainties in the measurement of reactor antineutrino absolute flux with the prospect experiment

Abstract

The Precision Reactor Oscillation and Spectrum Experiment (PROSPECT) was designed to investigateanomalies relating to the absolute flux and energy spectrum shape of antineutrinos emitted by 235U fissions in nuclear reactors, with a particular focus on searching for signs of sterile neutrino oscillations. The PROSPECT detector collected data from March to October 2018 at Oak Ridge National Laboratory’s High Flux Isotope Reactor. Although considerable work has been done to improve the measurements and models of the reactor antineutrino flux and spectrum, significant questions remain. This dissertation characterizes these anomalies and makes significant progress towards resolving them by using the PROSPECT dataset to measure the 235U antineutrino absolute flux, with a goal of obtaining a level of precision of roughly 2%, similar to the most precise measurement to date of the absolute flux made by the STEREO collaboration in 2023, through precise characterization of the uncertainties in the antineutrino detection efficiency.