A data readout approach for physics experiments

With increasing physical event rates and the number of electronic channels, traditional readout schemes meet the challenge of improving readout speed caused by the limited bandwidth of the crate backplane. In this paper, a high-speed data readout method based on the Ethernet is presented to make each readout module capable of transmitting data to the DAQ. Features of explicitly parallel data transmitting and distributed network architecture give the readout system the advantage of adapting varying requirements of particle physics experiments. Furthermore, to guarantee the readout performance and flexibility, a standalone embedded CPU system is utilized for network protocol stack processing. To receive the customized data format and protocol from front-end electronics, a field programmable gate array (FPGA) is used for logic reconfiguration. To optimize the interface and to improve the data throughput between CPU and FPGA, a sophisticated method based on SRAM is presented in this paper. For the purpose of evaluating this high-speed readout method, a simplified readout module is designed and implemented. Test results show that this module can support up to 70 Mbps data throughput from the readout module to DAQ.     

用于CBM-TOF超级模块质量评估的SoC数据读出方法

在高压缩重子物质（Compressed Baryonic Matter，CBM）实验中，多气隙电阻板室（Multi-gap Resistive Plate Chamber，MRPC）探测器被用于构建飞行时间（Time of Flight，TOF）谱仪。根据CBM实验需求，TOF谱仪被设计成由6种不同类型的超级模块构成的探测器墙。每个模块最多包含5块MRPC探测器，能提供320路电子学通道，单个模块的数据率高达6 Gbps。为了评估CBM-TOF超级模块的性能，本文提出了一种基于TCP/IP千兆以太网技术的数据读出方法。考虑到TCP/IP协议的复杂性，该方法利用AlteraSoC FPGA从前端电子学接受数字化的时间数据，并通过千兆以太网并行地发送数据到DAQ软件。实验室测试结果表明，单个读出扣板全链路读出速率达到550 Mbps，能够用于CBM-TOF MRPC探测器质量评估。     

中国散裂中子源反角白光中子束流参数的初步测量

中国散裂中子源(CSNS)已于2018年5月建设完工,随后进行了试运行.其中的反角白光中子束线(Back-n)可用于中子核数据测量、中子物理研究和核技术应用等多方面的实验.本文报道对该中子束的品质参数测量实验过程以及最终实验结果.实验主要采用中子飞行时间法,利用~(235)U,~(238)U裂变室和~6Li-Si探测器测量了中子能谱和中子注量率,又利用闪烁体-互补金属氧化物半导体探测系统测量了中子束斑的剖面,得到了该束线的初步实验测量结果.其中白光中子的全能谱测量范围eV—100 MeV,给出了不确定度分析;给出了中子注量率两个实验厅位置的满功率值;给出了白光中子在直径60 mm情况下的全能区束斑.通过与模拟结果的比较探讨了以上结果的合理性,并提出了改进计划.这些实验结果为以后该束线的核数据测量和探测器标定实验奠定了基础.