The mass production and batch test result of the 15K 20-inch MCP-PMT in NNVT for JUNO

The Jiangmen Underground Neutrino Observatory (JUNO) in China aiming to determine the neutrino mass hierarchy is under construction and the 15,000 MCP-PMTs produced in NNVT, which will be installed as the central liquid scintillator detector of JUNO, have been completed and delivered by August of 2020. During the mass production process, breakthrough of the photocathode technology greatly improved the quantum efficiency (QE) of the MCP-PMT from 30% to 35% and so the detection efficiency (DE) has been improved. The performance of other parameters keeps steady during the mass production process of 15,000 MCP-PMTs. The average QE at 400 nm for the 15,000 pieces of MCP-PMTs is 32%. With a layer of high-SEY material deposited on the MCP, the collection efficiency can reach nearly 100% and the average DE at 400 nm for the 15k pieces of MCP-PMTs is 31.5%.