The PROSPECT-II detector calibration system*

PROSPECT is a ton-scale reactor-based antineutrino experiment, operated at very short baselines from the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory. The PROSPECT experiment has reported strong limits on eV-scale sterile neutrinos, made a precision measurement of the reactor antineutrino spectrum from U-235, and demonstrated the observation of reactor antineutrinos in an aboveground detector with good energy resolution and well-controlled backgrounds. An upgraded detector, PROSPECT-II, will leverage existing expertise and investment and will resolve previous technical issues to ensure long term stability. The new design necessitates some changes to the calibration strategy. For example, the separation of photomultiplier tubes (PMTs) from liquid scintillator (LS) volume requires an alternative energy scale calibration method and careful consideration of introduced inter-segment cross-talk. This talk will describe calibration strategy for PROSPECT-II.