Towards a Precise Measurement of the ²³⁵U Antineutrino Spectrum with PROSPECT

PROSPECT, the Precision Oscillation and Spectrum Experiment, is a reactor antineutrino experiment designed to search for eV-scale sterile neutrinos and measure the spectrum of antineutrinos from highly-enriched ²³⁵U at the High Flux Isotope Reactor (HFIR). PROSPECT uses a 4-ton, segmented ⁶Li-doped liquid scintillator detector to make a high-resolution measurement of the prompt energy spectrum from inverse beta decay on protons. An optical and radioactive source calibration system integrated into the active detector volume is used to characterize the optical and energy response of all detector segments. We will discuss the calibration and characterization of the PROSPECT detector and report on PROSPECT’s first measurement of the energy spectrum associated with reactor antineutrinos.