大面积光电倍增管地磁场性能影响和寿命老化研究

发布时间：2018-03-03 19:24

本文选题：大面积PMT　切入点：MCP-PMT　出处：《南京大学》2015年硕士论文　论文类型：学位论文

【摘要】：光电倍增管(PMT)是探测极其微弱光的真空器件。在高能物理中,利用光电倍增管探测粒子事件产生的极微弱的光信号,达到间接探测粒子的目的。随着微通道板(MCP)技术的发展,微通道板被用于制备光电倍增管的倍增阳极,从而研制成微通道板型光电倍增管,在光电倍增管的探测性能上有了很大的改善。针对江门中微子实验(JUNO)实验的具体需求,高能物理研究所有关研究人员设计了一款基于微通道板的大面积高量子效率的微通道板型光电倍增管,并且高能物理研究所组织了微通道板型光电倍增管研制合作组,共同研制开发此款样品。我参与了这种新型光电倍增管测试工作,例如光电倍增管的单光子谱、高压增益曲线、光阴极量子效率、光阴极光谱响应、光阴极均匀性、后脉冲、暗计数率、时间涨落等工作,并主要研究了地磁场对光电倍增管性能的影响和大面积微通道板型光电倍增管的老化。光电倍增管是受地磁场影响较为敏感的电子学器件,甚至及微弱的地磁场也会对光电倍增管造成很大的影响。在大型探测器中,需要考虑地磁场对光电倍增管性能的影响。在本论文中,我们设计了两套测量地磁场对光电倍增管影响的测试系统：单轴旋转系统和三轴旋转系统。通过单轴旋转系统,可以测试由于光电倍增管结构的不均匀性引起的地磁场对光电倍增管的影响；通过三轴旋转系统,可以测试由于光电倍增管安装位置的不同而引起的地磁场对光电倍增管的影响。实验中还使用了磁屏蔽材料对地磁场进行屏蔽,可以看出,磁屏蔽材料可以很大程度地减弱地磁场对光电倍增管的影响。根据三轴旋转系统的测试结果,使用基坐标分解,可以计算出地磁场对光电倍增管性能的影响强度在整个球面上的分布。我们对合作组研制的8寸新型大面积光阴极微通道板型光电倍增管进行老化测试。老化期间,在每天特定的时间测试光电倍增管的多光电子谱,单光电子谱及暗噪声谱。为了进行交叉验证,我们先后对两只光电倍增管进行了相似的老化测试,第一只光电倍增管老化52天,第二只光电倍增管老化84天。为了深入研究光电倍增管老化的原理,在第二只光电倍增管老化的结束与开始,也测试了光电倍增管的阴极电流和电阻。并且当光电倍增管的累计输出电荷为4C时,我们增加了第二只光电倍增管的高压,提高了光电倍增管的老化速度。根据光电倍增管的老化曲线,我们建立了光电倍增管的老化模型,给出了光电倍增管的一般老化公式。研究表明,光阴极的老化不是大面积微通道板型光电倍增管老化的主要因素,大面积微通板型光电倍增管的老化主要与MCP的老化有关。
[Abstract]:Photomultiplier tube (PMT) is a vacuum device for detecting extremely weak light. In high energy physics, the use of photomultiplier tubes to detect very weak light signals produced by particle events can achieve the purpose of indirectly detecting particles. The microchannel plate has been used to prepare the multiplication anode of photomultiplier tube, and the microchannel plate photomultiplier tube has been developed. The detection performance of the photomultiplier tube has been greatly improved. The researchers of the Institute of High Energy Physics have designed a large area and high quantum efficiency photomultiplier tube based on microchannel plate, and the Institute of High Energy Physics has organized the research and development cooperation group of microchannel plate photomultiplier tube. I participated in the testing work of this new photomultiplier tube, such as single photon spectrum of photomultiplier tube, high voltage gain curve, photocathode quantum efficiency, photocathode spectral response, photocathode uniformity, post pulse. The influence of geomagnetic field on the performance of photomultiplier tube and the aging of plate photomultiplier tube with large area microchannel are studied. Photomultiplier tube is a sensitive electronic device affected by geomagnetic field. Even a weak geomagnetic field will have a great effect on photomultiplier tubes. In large detectors, the effect of geomagnetic field on the performance of photomultiplier tubes should be considered. We have designed two test systems to measure the effect of geomagnetic field on photomultiplier tubes: uniaxial rotation system and triaxial rotation system. The effect of geomagnetic field on photomultiplier tube caused by the inhomogeneity of photomultiplier tube structure can be tested. The effect of geomagnetic field on photomultiplier tube caused by different position of photomultiplier tube can be tested. Magnetic shielding materials can greatly reduce the effect of geomagnetic field on photomultiplier tubes. The influence of geomagnetic field on the properties of photomultiplier tubes can be calculated. We have tested the 8-inch photocathode microchannel plate photomultiplier tubes developed by the cooperative group during aging. The multiple photoelectron spectra, single photoelectron spectra and dark noise spectra of photomultiplier tubes are tested at a specific time of day. In order to cross-verify, we have carried out similar aging tests on two photomultiplier tubes. The first photomultiplier tube aged 52 days, the second one aged 84 days. In order to study the principle of photomultiplier tube aging, at the end and beginning of the second photomultiplier tube aging, We also tested the cathode current and resistance of the photomultiplier tube, and when the cumulative output charge of the photomultiplier tube was 4C, we added the high voltage of the second photomultiplier tube. According to the aging curve of photomultiplier tube, the aging model of photomultiplier tube is established, and the general aging formula of photomultiplier tube is given. The aging of photocathode is not the main factor of the aging of large area microchannel plate photomultiplier tube. The aging of large area micro-pass plate photomultiplier tube is mainly related to the aging of MCP.
【学位授予单位】：南京大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN152

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