Comparison on PMT waveform reconstructions with JUNO prototype

Abstract

JUNO is a 20 kton underground liquid scintillator detector aiming to determine the neutrino mass hierarchy and neutrino measurements. A prototype of JUNO is designed and set up for better understanding sub-systems of future detector. The preliminary results show that trigger rate is about 290 Hz at threshold 0.3 MeV (gamma) on the surface of earth, containing cosmic muon rate ∼35 Hz identified by detected energy higher than 20 MeV . For a better detector understanding with PMT signal, three waveform reconstruction algorithms are compared for PMTs with different overshoot ratios, including charge integration, waveform fitting, and deconvolution. It is concluded that the deconvolution algorithm is best to handle larger overshoot (∼10%) while a selected time window length would affect the reconstruction uncertainty. Further, the three reconstruction algorithms show similar performance on consistency and uncertainty with small overshoot (∼1%) waveforms and different amplitudes, which means that the simplest charge integral method is still working well for quick waveform reconstruction in this case.