Current status of JUNO Top Tracker

Abstract

The JUNO experiment is a multi-purpose antineutrino oscillation experiment with the main objective of determining the neutrino mass hierarchy with a sensitivity better than 3\(\sigma\), which requires JUNO to have an energy resolution better than 3% at 1MeV. The JUNO Central Detector, a 20 kton liquid scintillator detector, will be built with high PMT photocathode coverage and good transparency for this purpose. Despite the 700m overburden, the atmospheric muon-induced background is still estimated to be non negligible compared to the expected signal for the neutrino mass hierarchy determination. A veto system was designed for muon detection to tag and to suppress this background. It consists of two subsystems: the Top Tracker and the Water Cherenkov Detector. The Top Tracker is a 3-layer muon tracker covering about 60% of the top surface above the JUNO water pool and will provide precise tracking for atmospheric muons. These well reconstructed muons are essential in the veto strategy for rejecting cosmogenic isotope background. Combining the muon information from the Top Tracker and the Water Cherenkov Detector, most of the atmospheric muon-induced background can be removed. This proceeding will present the current status and the expected performance of the JUNO Top Tracker.