光电倍增管大动态范围电荷测量电路的研究

发布时间：2018-06-06 12:20

  本文选题：高海拔宇宙线观测站 + 空气簇射芯探测器　； 参考：《湖南大学》2016年硕士论文

【摘要】：宇宙线的探测和研究是人们揭开宇宙空间神秘面纱的重要手段,寻找宇宙线起源是当前宇宙线物理的核心问题。为此,我国物理学家提出了多种探测手段联合观测的高海拔宇宙线观测站(Large High Altitude Air Shower Observatory, LHAASO)计划,计划中的空气簇射芯探测器阵列(SCDA)的主要目的是精确测量宇宙线大气簇射轴芯区的高能电磁成份。在此背景下,本文开展了对SCDA读出电子学电荷测量方案的预研设计。SCDA读出电子学系统的主要任务是精确测量光电倍增管(PMT)输出的电荷量。为实现高精度、大动态范围电荷量的测量,本设计采用了基于电流积分法的电荷测量方案,并结合电子学设计指标对该方案进行优化设计研究,对其中的电流积分电路、滤波成形方案等部分进行理论分析、Pspice仿真验证。另外由于SCDA的分散式排布方式,读出电子学需通过同轴电缆与探测器连接。为防止信号的反射,本设计在电子学前端与电荷积分放大器的虚地点之间接入等效的50欧姆电阻以实现终端阻抗匹配,并提出了适用于大动态范围电荷测量电路的并联分流形式的阻抗匹配方案。基于电荷测量方案的研究,本文从模拟电路设计、电子学PCB版图设计以及FPGA固件设计这几方面详细介绍了读出电子学原理样机的研制。并在实验室搭建了模拟实际工程的测试系统对电荷测量电路进行电荷测量范围、测量精度、积分非线性等参数的测试,测试结果表明本电荷测量电路系统能实现在6.2pC～8118 pC电荷测量范围下电荷测量精度达到1.12%,其满量程积分非线性为0.234%,满足电子学设计指标要求。另外,由于采用并联分流的“虚地”阻抗匹配方案,读出电子学系统可以通过简单的调节并联电阻比值实现不同电荷量的测量。文中也对此进行了测试,测试结果表明本电路系统在不同的电荷量输入情况下具有很好的适用性。
[Abstract]:The detection and study of cosmic rays is an important means for people to uncover the mystery of cosmic space. Finding the origin of cosmic rays is the core problem of cosmic ray physics at present. For this reason, physicists in our country have put forward the large High Altitude Air Shower Observatory, LHAASO) program of the high altitude cosmic ray observation station, which is observed jointly by a variety of exploration methods. The main purpose of the planned air shower core detector array (SCDAA) is to accurately measure the high energy electromagnetic composition in the cosmic ray atmosphere shower core. In this context, the main task of the SCDA readout electronics system is to accurately measure the charge output of the photomultiplier tube. In order to measure charge in high precision and large dynamic range, a charge measurement scheme based on current integration method is used in this design. The optimization design of the scheme is carried out in combination with the electronic design index, and the current integral circuit is designed. The filter shaping scheme is analyzed theoretically and verified by PSpice simulation. In addition, due to the distributed arrangement of SCDA, readout electronics must be connected to the detector via coaxial cable. In order to prevent the reflection of the signal, the design connects the equivalent 50 ohms resistance between the electronic front end and the virtual location of the charge integral amplifier to achieve the terminal impedance matching. A parallel shunt impedance matching scheme is proposed for charge measurement circuits in large dynamic range. Based on the research of charge measurement scheme, this paper introduces the design of readout electronics principle prototype in detail from the aspects of analog circuit design, electronic PCB layout design and FPGA firmware design. At the same time, a testing system is set up in the laboratory to test the parameters of charge measurement circuit, such as the range of charge measurement, the accuracy of measurement, the integral nonlinearity, etc. The test results show that the charge measurement circuit system can realize the accuracy of charge measurement in the range of 6.2pC~8118 PC charge measurement, and its full range integral nonlinearity is 0.234, which meets the requirements of electronic design. In addition, because of the parallel shunt "virtual earth" impedance matching scheme, the readout electronic system can simply adjust the ratio of parallel resistance to realize the measurement of different charge quantities. The test results show that the circuit system has good applicability under different charge input conditions.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TH75
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本文编号：1986490