| Photomultiplier tube(PMT) is a kind of vacuum device which is used to detec-t very weak light. Specially, it is used to detect the event of very weak particles indirectly in the high energy physics. With the development of the micro channel plate(MCP) technology, MCP is used in the photomultiplier tube as electron multipli-er, which greatly improved the performance of the photomultiplier tube.Researchers from the Institute of High Energy Physics, Chinese Academy of Sci-ences (CAS) designed a new kind of large area, high quantum efficiency of MCP-PMT for JUNO experiment. In order to research and develop this kind of PMT, a calibration was setup. I participated in the work of testing the properties of single photon spec-trum, high voltage gain curve, quantum efficiency, dark count rate, homogeneity etc. I mainly studied the earth’s magnetic field influences on the testing property and aging performance for this kind of MCP-PMT.Photomultiplier tube is sensitive to magnetic field, especially with large area PMT. In large a detector, it is necessary to consider the influence of the geomagnetic effect on PMT. In this thesis, we designed two sets of test:the uniaxial rotation system and triaxis rotation system. Through uniaxial rotation system, the earth’s magnetic effect on PMT caused by the photomultiplier tube structure uniformity was tested. Through the triaxial rotation system, the earth’s magnetic effect on PMT caused by the photo-multiplier tube’s installation position was also tested. Magnetic shielding material was used for shielding the magnetic field’s influence on the photomultiplier tube. It can be seen that the magnetic shielding material can greatly eliminate the influence of the magnetic field on photomultiplier tubes. According to the test results of triaxis rotation system, using of the base coordinate decomposition, it is easy to calculate the distribu-tion of the magnetic effect on the properties of photomultiplier tubes on the surface of a sphere.An aging experiments of a novel type of large area MCP-PMT made by JUNO col-laboration were conducted. In this aging experiment, the multi-photoelectron spectrum and single photoelectron spectrum were measured daily, as well as the MCP resistance of the second PMT before and after the experiment. Two PMTs were aged successively for cross check. The first PMT was aged for 52 days, while the other one was aged for 84 days. In order to study the mechanism of the aging process, the high voltage on the second PMT was increased to accelerate its aging process when the cumulative output of charge from its anode was about 4 C. From our study, it can be known that large area PMT aging had a strong relationship with the related MCPs. In accordance with the PMT aging curve, a PMT aging model was setup and a general aging formula was given. |
PDF Full Text Request