[en] In order to meet the requirement of JUNO, 20-inch microchannel plate photomultiplier (MCP-PMT) was researched by the MCP-PMT collaboration, which was established by Institute of High Energy Physics (IHEP) and North Night Vision Technology Co., Ltd. (NNVT) in 2012. By the breakthrough of the key technology, such as the electronic optics structure design, the high quantum efficiency photocathode process, and so on, the 20-inch MCP-PMT was developed successfully by 2015. The collection efficiency was about 98% and the detection efficiency (DE) was about 26%. At the same year, NNVT successfully bided for the 15000 PMTs of JUNO. In order to finish the contract of MCP-PMTs, the production line of 20-inch MCP-PMT was built on the 25th Nov of 2016. The production line was the domestic advanced photomultiplier production line with capable of 7500 pieces 20-inch MCP-PMTs a year. By building the batch test system, the charge performance of 32 pieces PMTs could be tested at the same time. Recently, NNVT had delivered JUNO total 7000 pieces 20-inch MCP-PMTs. The average DE was increased to 30% from 27% since June 2018, and the average dark count rate was about 30 kHz. Based on the research finding of 20-inch MCP-PMT for JUNO, the 20-inch MCP-PMT with good time response was researched to meet the requirement of Hyper-K project, and developed successfully. The new 20-inch MCP-PMT had a flower-like focusing electrode. The transit time spread was about 5 ns, namely FWHM, better than the one of the original 20-inch MCP-PMT with 14 ns. (author)

[en] A new concept of large area photomultiplier based on MCPs was conceived for JUNO by the scientists in IHEP, Beijing. In the past 5 years by collaborative work of the MCP-PMT collaboration in China, 8 inch and 20 inch prototypes were produced. Test results show that this type of MCP-PMT can have similar photon counting performance as the traditional dynode type PMTs. With the better collection efficiency, low after pulse rate, low Low-Potassium Glass, the JUNO ordered 75% about 15,000 20 inch MCP-PMT from NNVT at the end of 2015. This manuscript just give the overview this type of MCP-PMT, the R and D process and the main characteristics. (paper)

[en] A novel large-area (20-inch) photomultiplier tube based on microchannel plate (MCP-PMTs) is proposed for the Jiangmen Underground Neutrino Observatory (JUNO) experiment. Its photoelectron collection efficiency C_e is limited by the MCP open area fraction (A_o_p_e_n). This efficiency is studied as a function of the angular (θ), energy (E) distributions of electrons in the input charge cloud and the potential difference (U) between the PMT photocathode and the MCP input surface, considering secondary electron emission from the MCP input electrode. In CST Studio Suite, Finite Integral Technique and Monte Carlo method are combined to investigate the dependence of C_e on θ, E and U. Results predict that C_e can exceed A_o_p_e_n, and are applied to optimize the structure and operational parameters of the 20-inch MCP-PMT prototype. C_e of the optimized MCP-PMT is expected to reach 81.2%. Finally, the reduction of the penetration depth of the MCP input electrode layer and the deposition of a high secondary electron yield material on the MCP are proposed to further optimize C_e.

[en] A new concept of large area photomultiplier based on MCPs was conceived for JUNO by the scientists in IHEP, and with the collaborative work of the MCP–PMT collaboration in China, 8 in. and 20 in. prototypes were produced. Test results show that this type of MCP–PMT can have good SPE performance as the traditional dynode type PMTs.

[en] To obtain a high spatial resolution of a image intensifier based on microchannel plate (MCP), the long tail in the exit energy distribution of the output electrons (EDOE) is undesirable. The existing solution is increasing the penetration depth of the MCP output electrode, which will result in a serious gain reduction. Coating the MCP output electrode with efficient secondary electron yield (SEY) materials is supposed to be an effective approach to suppress the unfavorable tail component in the EDOE without negative effects on the gain. In our work, a three-dimensional MCP single channel model is developed in CST STUDIO SUITE to systematically investigate the dependences of the EDOE and the gain on the SEY property of the coated material, based on the Finite Integral Technique and Monte Carlo method. The results show that besides the high SEY of the coated material, the low incident energy corresponding to the peak SEY is another essential element affecting the electron yield in the final stage of multiplication and suppressing the output energy spread.