Reduction of the 14C-background in the JUNO experiment

Abstract

The Jiangmen Underground Neutrino Observatory (JUNO) will be a 20kt liquid scintillator neutrino detector located at Kaiping, Jiangmen in South China. With the data aquisition starting in 2021, its main goal is the determination of the neutrino mass hierarchy from a precise measurement of the energy spectrum of anti-electron-neutrinos 53km away from the reactor. To precisely measure the oscillation pattern of the reactor spectrum an unpredecent energy resolution for this kind of detector of 3% at 1MeV is needed. Pile-up events with background from radioactive decays such as those from 14C can spoil the reconstruction of the neutrino energy. On this poster methods for detecting pile-up events are presented. In addition to a simple clusterization algorithm on the hit times, the utilization of spherical harmonics of the hit distribution as well as a Likelihood-test of the hit times are used to tag pile-up events.