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 30% at 400nm. Its Peak/Valley (P/V) ratio for the single photoelectron is 4.75 and the dark count rate is 27kHz at the threshold of 3 mV while the gain is at 1×107. The transit time spread of a single photoelectron is 2.86ns. Generally the performances of this new 20-inch PMT are improved over the old one of R3600.
@article{arxiv.1504.03174,
title = {Evaluation of new large area PMT with high quantum efficiency},
author = {Xiang-Cui Lei and Yue-Kun Heng and Sen Qian and Jing-Kai Xia and Shu-Lin Liu and Zhi Wu and Bao-Jun Yan and Mei-Hang Xu and Zheng Wang and Xiao-Nan Li and Xiang-Dong Ruan and Xiao-Zhuang Wang and Yu-Zhen Yang and Wen-Wen Wang and Can Fang and Feng-Jiao Luo and Jing-Jing Liang and Lu-Ping Yang and Biao Yang},
journal= {arXiv preprint arXiv:1504.03174},
year = {2016}
}