Characterization of 3-inch photomultiplier tubes for the JUNO central detector

摘要

Background Jiangmen Underground Neutrino Observation (JUNO) is one of the largest experimental facilities for neutrino detecting. As its main structure, the central detector contains 20 kiloton liquid scintillator filled in an acrylic shell, and there are 18,000 20-inch photomultipiier tubes (PMTs) and 25,000 3-inch PMTs covering the shell. Purpose As an independent photon detection system, 3-inch PMTs have been required to have excellent resolution for the single photoelectron detection, high quantum efficiency, small transit time spread and low dark noise rate. Methods Two kinds of 3-inch PMTs from HZC Photonics and Hamamatsu have been investigated as candidates. A dedicated test system for 3-inch PMTs has been designed, and various characterization parameters have been studied. Conclusion The preliminary results show these PMTs can meet the requirements of JUNO.