闪烁体中子探测器光电倍增管读出电路设计与实现

发布时间：2018-08-27 18:35

【摘要】：中国散裂中子源(China Spallation Neutron Source,CSNS)是国家在建的重大科技基础设施,由加速器提供高能质子轰击金属靶而产生高通量的中子源,将为国内外科学家提供世界一流的中子科学综合实验装置。通用粉末衍射仪(General Purpose Powder Diffractometer,GPPD)是CSNS首批建设的三台谱仪之一,采用大面积位置灵敏型闪烁体中子探测器(Position-sensitive Scintillation Neutron Detector,SSND)。SSND的输出信号经波移光纤吸收重发射后输入到多阳极光电倍增管(Multi-anode Photo Multiplier Tubes,MaPMT),由电子学系统进行数据处理。MaPMT_v10是高能物理研究所自主研发的一款适用于闪烁体中子探测器光电倍增管信号读出的16通道专用集成电路(Application-specific Integrated Circuit,ASIC),每个通道包括电荷灵敏前置放大器、滤波成形、甄别和单稳态输出电路。本文设计了闪烁体中子探测器光电倍增管读出电路,采用MaPMTB_v10对光电倍增管输出的模拟信号进行放大、成形、甄别,输出的数字信号由FPGA进行数据处理,实时获取系统所需的时间信息和位置信息,通过USB2.0协议将数据传输至上位机进行验证。论文主要内容包括:对闪烁体中子探测器读出电路的设计需求进行分析;完成读出电路的整体结构设计,并按照信号输入模块、模拟信号处理模块、FPGA数据处理模块、数据传输模块、电源模块、时钟模块等进行硬件设计;完成读出电路PCB版图设计;使用Verilog HDL语言在ISE14.4开发环境下完成了FPGA固件开发。最后对读出电路板的数据处理及传输功能进行了测试,并对ASIC的线性、噪声等性能进行了测试。测试结果表明,该读出电路实现了对中子到达时间及位置信息的获取及传输,ASIC的线性度范围为0.72%-1.1%,等效输入噪声典型值为5.49f C,满足设计要求。
[Abstract]:China Spallation Neutron Source (China Spallation Neutron Source,CSNS) is a major scientific and technological infrastructure under construction in China. High throughput neutron sources are produced by high energy protons bombarded metal targets by accelerators. Will provide the world-class neutron science comprehensive experimental equipment for the domestic and foreign scientists. The universal powder diffractometer (General Purpose Powder Diffractometer,GPPD) is one of the first three spectrometers built by CSNS. The output signal of a large area position sensitive scintillator neutron detector (Position-sensitive Scintillation Neutron Detector,SSND) .SSND is absorbed and retransmitted by wave-shifted optical fiber and input to a multi-anode photomultiplier tube (Multi-anode Photo Multiplier Tubes,MaPMT). The data processing is carried out by electronic system. MaPMTv10 is a high-energy substance. The Institute has developed a 16-channel specialized integrated circuit (Application-specific Integrated Circuit,ASIC), each of which includes a charge-sensitive preamplifier, for readout of a photomultiplier tube signal from a scintillator neutron detector. Filter shaping, screening and Monostable output Circuits. In this paper, the readout circuit of photomultiplier tube for scintillator neutron detector is designed. The analog signal of photomultiplier tube is amplified, formed and identified by MaPMTB_v10, and the digital signal is processed by FPGA. The time and position information of the system is obtained in real time, and the data is transmitted to the upper computer by USB2.0 protocol for verification. The main contents of this paper are as follows: the design requirements of the scintillator neutron detector readout circuit are analyzed, the whole structure of the readout circuit is designed, and according to the signal input module, the analog signal processing module and the FPGA data processing module are presented. Data transmission module, power supply module, clock module and so on are designed; PCB layout design of readout circuit is completed; FPGA firmware is developed in ISE14.4 development environment by using Verilog HDL language. Finally, the data processing and transmission functions of the readout circuit board are tested, and the linearity and noise of ASIC are tested. The test results show that the readout circuit achieves the linear range of 0.72-1.1 for the acquisition and transmission of neutron arrival time and position information, and the equivalent input noise is 5.49fC, which meets the design requirements.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O571.53;TN152

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