分类: 物理学 >> 核物理学 提交时间: 2016-09-13
摘要: The neutrino detector of the Jiangmen Underground Neutrino Observatory (JUNO) is designed to use 20 kilotons of liquid scintillator and approximately 16,000 20-inch photomultipliers (PMTs).One of the options is to use the 20-inch R12860 PMT with high quantum efficiency which has recently been developed by Hamamatsu Photonics. The performance of the newly developed PMT preproduction samples is evaluated. The results show that its quantum efficiency is�0%燼t�00nm. Its Peak/Valley (P/V) ratio for the single photoelectron is 4.75 and the dark count rate is�7kHz燼t the threshold of 3 mV while the gain is at��07. The transit time spread of a single photoelectron is2.86ns. Generally the performances of this new 20-inch PMT are improved over the old one of R3600.
分类: 物理学 >> 核物理学 提交时间: 2016-08-31
摘要: The quality of PMT signal is one of the key items for a large and high precision neutrino experiment, like Daya Bay, JUNO, while most of the experiments are affected by the PMT signal overshoot from its positive HV-single cable scheme. For JUNO prototype detector, we have a detailed study on the PMT overshoot and successfully reduced the ratio of overshoot amplitude to signal to ~1% from previous typical ~10%, with no affection to PMT other parameters. Furthermore, we calculated that the overshoot is a result of discharging of capacitors in the HV-signal splitter and the PMT voltage divider. The study result is extremely important for JUNO and other similar experiments.