The Status of the 20 inch MCP-PMT and its APR Test Result

Researchers at IHEP have conceived a new concept of MCP-PMT several years ago. The small MCP units replace the bulky Dynode chain in the large PMTs. In addition the transmission and reflection photocathode are applied in the same glass bulb to enhance the efficiency of photoelectron conversion. After several years R&D, the 20 inch MCP-PMT was successfully produced for JUNO. From 2017 to 2020, all the 20-inch PMTs for JUNO have been under production and testing in NNVT. Furthermore, the QE of this type of MCP-PMT is improved from 28% to 34%@400nm in 2018, and this new technology has already been used on the PMT mass production. The after-pulse rate of this type of the HQE-MCP-PMT was also evaluated at gain ~1.0×10
⁷
in this manuscript.