Photomultiplier tubes (PMTs) are widely used underwater in large-scale neutrino experiments. As a hollow glass spherelike structure, implosion is unavoidable during long-term operation under large water pressure. There is a possibility of cascade implosion to neighbor PMTs due to shockwave. Jiangmen Underground Neutrino Observatory designed a protection structure for each 20-inch PMT, consisting of a top cover, a bottom cover, and their connection. This paper introduces the requirement and design of the PMT protection system, including the material selection, investigation of manufacture technology, and prototyping. Optimization and validation by simulation and underwater experiments are also presented.
@article{arxiv.2209.08441,
title = {Design of the PMT underwater cascade implosion protection system for JUNO},
author = {Miao He and Zhonghua Qin and Shaojing Hou and Xiaoping Jing and Hongbang Liu and Zunjian Ke and Diru Wu and Wan Xie and Mehang Xu and Fang Chen and Junguang Lu and Yuekun Heng and Jiawen Zhang and Xiaoyan Ma and Zhipeng Du},
journal= {arXiv preprint arXiv:2209.08441},
year = {2023}
}