MWPC探测器读出电子学系统的设计与实现

发布时间：2018-02-21 02:43

本文关键词： CSNS FPGA ASIC Lab VIEW 多丝正比室电荷测量位置测量　出处：《湖南大学》2015年硕士论文　论文类型：学位论文

【摘要】：中国散裂中子源(China Spallation Neutron Source,CSNS)是我国“十一五”期间重点建设的大型科学装置。它利用高能质子轰击重金属靶来产生中子,有效提高了传统中子源的通量上限,为我国各类基础学科的前沿领域研究提供了一个先进且功能强大的科研平台。CSNS初期建设的三台谱仪有通用粉末衍射仪、小角散射仪和多功能反射仪。其中小角散射仪和多功能反射仪中都用到了二维多丝正比室探测器(Multi-Wire Proportional Chamber,MWPC),本论文主要针对MWPC探测器的电子学读出方案、具体实现以及最终读出系统样机的性能测试进行了深入的研究。本设计由电子学读出板卡、FPGA固件程序以及PC端应用程序构成。其中读出板卡采用Xilinx公司的现场可编程门阵列(Field Programmable Gate Array,FPGA)作为板上各芯片的控制器和数据处理器,可同时处理多个通道的探测器信号。板上对探测器位置信号的获取和处理采用挪威IDEAS公司的多通道专用集成电路(Application Specific Integrated Circuit,ASIC)。与以往位置测量采用分立器件加运放的硬件结构相比,本设计的优点有:功耗低、占用空间小、信噪比高、硬件成本小等优点。由于FPGA的固件开发简便且易于升级更新,所以在不改变硬件的情况下读出板整体的功能仍有很高的灵活性。PC端应用程序在NI公司的图形化编程环境Lab VIEW2012下调用C语言实现。它具有界面友好、操作方便等特点,可根据需求对板上的工作模式进行配置、读回板上数据包、实时分析并对结果直观显示。一般的粒子探测器常工作于强电磁干扰环境中,这种环境下信号的长距离传输必然受到严重的干扰。本设计采用ASIC和FPGA实现了MWPC探测器的电子学读出,大大提高了电子学读出系统的集成度,减小了整个读出板卡的体积,可使其轻松挂载与探测器上。这样,经读出板处理后的信号变为数字信号,易于传输至PC端或下级数据汇总板卡。另外,本设计采用数字法对位置进行读出,设置合适的阈值能大大提高有效事例的计数率。综上所述,作为CSNS多功能反射谱仪中MWPC探测器的电子学读出研究,本设计具有较高的理论和实际意义,最终的测试结果对将来的工程应用有很好的指导作用。
[Abstract]:China Spallation Neutron SourceNs is a large scientific device which is mainly built during the 11th Five-Year Plan period in China. It produces neutrons by bombarding heavy metal targets with high energy protons, which effectively increases the flux upper limit of traditional neutron sources. It provides an advanced and powerful scientific research platform for the frontier research of various basic disciplines in China. The three spectrometers, which were initially built by CSNS, have universal powder diffractometer. Small-angle scatterometer and multifunctional reflectometer are used in both small angle scatterometer and multifunctional reflector. Multi-Wire Proportional Chamber MWPCO detector is used in this paper. In this paper, the electronic readout scheme of MWPC detector is mainly focused on the electronic readout scheme of MWPC detector. The design is composed of electronic readout card FPGA firmware program and PC application program. The readout card is based on Xilinx company. The Field Programmable Gate FPGA is used as the controller and data processor for each chip on the board. The detector signal of multiple channels can be processed at the same time. The acquisition and processing of detector position signal on the board adopts the multi-channel application Specific Integrated circuit of Norway IDEAS company. Compared with the hardware structure in which the discrete device is used in the previous position measurement, The advantages of this design are: low power consumption, small footprint, high signal-to-noise ratio, low hardware cost, etc. The firmware development of FPGA is simple and easy to update. So without changing the hardware, the whole function of the readout board is still very flexible. The PC application program is realized by C language in the graphic programming environment of NI company, Lab VIEW2012. It has friendly interface and convenient operation. The working mode on the board can be configured according to the demand, the data packet on the board can be read back, the results can be analyzed in real time and the results can be displayed intuitively. Generally, the particle detectors often work in the environment of strong electromagnetic interference. In this environment, the long distance transmission of signals is bound to be seriously disturbed. In this design, ASIC and FPGA are used to realize the electronic readout of the MWPC detector, which greatly improves the integration of the electronic readout system and reduces the volume of the whole readout board. It can be easily mounted and mounted on the detector. In this way, the signal processed by the readout board becomes a digital signal, which is easily transmitted to the PC terminal or the lower level data summary board. In addition, the design adopts the digital method to read out the position. To sum up, as an electronic readout study of MWPC detector in CSNS multifunctional reflectance spectrometer, this design has high theoretical and practical significance. The final test results have a good guidance for future engineering applications.
【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】：TN791;O571.53

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