Online analysis for the OSIRIS pre-detector of JUNO

The Jiangmen Underground Neutrino Observatory (JUNO) is a 20 kton liquid scintillator experiment currently under construction in the vicinity of the Pearl River Delta in Southern China. The data-taking is expected to start in 2022. JUNO aims to address a vast variety of physics goals in a broad range of energies. Its main focus lies on the determination of the Neutrino Mass Ordering measuring the oscillated reactor electron anti-neutrino spectrum from two adjacent nuclear power plants. Such measurements in the low-energy regime are affected and would suffer from high unexpected radioactive contaminations in the liquid scintillator. To ensure these strict limits, the OSIRIS pre-detector is designed to monitor the radioactivity of the liquid scintillator during the filling process of the JUNO detector. It holds 18 tons of scintillator and is instrumented via 76 large 20-inch PMTs. To provide an early warning of such a highly contaminated scintillator, the data from the OSIRIS detector needs to be evaluated in real-time. The corresponding online monitor software and analysis will be presented in this talk