摘要
Background:The Jiangmen Underground Neutrino Observatory(JUNO)is a multi-purpose neutrino experiment designed to measure the neutrino mass hierarchy using a central detector(CD),which contains 20 kton liquid scintillator(LS)surrounded by about 18,000 photomultiplier tubes(PMTs),located 700 m underground.Purpose:The rate of cosmic muons reaching the JUNO detector is about 3 Hz,and the muon-induced neutrons and isotopes are major backgrounds for the neutrino detection.Reconstruction of the muon trajectory in the detector is crucial for the study and rejection of those backgrounds.Methods:This paper will introduce the muon-tracking algorithm in the JUNO CD,with a least-squares method of PMTs’first-hit time(FHT).Correction of the FHT for each PMT was found to be important to reduce the reconstruction bias.Results:The spatial resolution and angular resolution are better than 3 cm and 0.4 degree,respectively,and the tracking efficiency is greater than 90%up to 16 m far from the detector center.
基金
This work is supported by National Natural Science Foundation of China(Grant Nos.11575226,11605222)
Joint Large Scale Scientific Facility Funds of NSFC and CAS(Grant No.U1532258)
the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA10010900)。
