高计数率复杂事例判选无触发核数据获取系统关键问题研究

More and more nuclear experiment facilities with high input event rate and complex event selection algorithms are constructing. Though conventional data acquisition (DAQ) system cannot be used in these facilities, trigger-less data acquisition (TLDAQ) system can be used due to its advantages. However, the development of TLDAQ system is limited because of the non-scalability of its architecture, the deficient timestamp strategy and the incompletion of data preprocessing method. Therefore, this project decide to research the key problems of TLDAQ system, which prevent the development of TLDAQ system, using hardware-in-loop simulation method which has the advantages of low-cost and providing special operation condition. Firstly, a scalable architecture of TLDAQ system is researched. Data preprocessing algorithms will be divided into two parts: dedicated algorithms and algorithms of universal purpose; dedicated algorithms are implemented by a Front End Electronics readout module based on FPGA; algorithms of universal purpose are implemented by a data preprocessing module of universal purpose. Secondly, the timestamp strategy is investigated. With the help of the flexibility of FPGA, a method used to generate timestamp and a data frame format are studied. At last, a stable data preprocessing method is researched. Using the characteristic of getting data sequentially for TLDAQ system, a frame merging algorithm is implemented based on multiple state machines technology, and a data sorting algorithm is implemented based on multiple FIFO technology. The research result can promote the theory of TLDAQ system and the development of nuclear experiments.

越来越多的新建高计数率核实验装置需要复杂事例判选算法，传统数据获取系统已无法满足要求，而无触发数据获取(TLDAQ)系统由于其自身优势，将是必然的发展方向，但其架构缺乏通用性、时间标记策略和数据预处理方法不完善限制了它的发展。本课题拟使用具有低成本、能验证特殊工况等特点的“半实物仿真”实验方法来研究限制TLDAQ系统发展的关键问题。具体来讲：首先，将预处理算法划分为通用算法和特定探测器专用算法，分别由通用型数据预处理模块和基于FPGA的前端电子学读出模块承担，探索通用型TLDAQ系统架构；其次，利用FPGA的灵活配置特性，探寻时间标记信息的产生方法和数据帧结构，完善时间标记策略；最后，结合TLDAQ系统按时间顺序获取数据的特点，研究多状态机的帧合并算法和基于多FIFO的并行数据排序算法，构建稳定的数据预处理方法。研究结果既能发展与完善TLDAQ系统理论，又能为新型核实验的顺利进行奠定基础。

越来越多的新建高计数率核实验装置需要复杂事例判选算法，传统数据获取系统已无法满足要求，而无触发数据获取(TLDAQ)系统由于其自身优势，将是必然的发展方向，但其架构缺乏通用性、时间标记策略和数据预处理方法不完善限制了它的发展。本项目通过将前端电子学模块归纳为电模块和光模块，从而将数据预处理板卡设计为提供2路FMC电接口，4路SFP光接口的模块，能配置为前端电子学模块和数据预处理板卡功能，从而解决了通用性的问题；设计了一套涵盖单个通道数据、前端电子学模块数据和预处理板卡数据的帧结构，保证时间标记信息能完整的传输给后端计算机，同时设计了一套系统同步方法，便于所有模块的时钟同步；为了提供在线数据处理能力，通过万兆以太网方法建立了计算机群模型，实现高速数据传输和实时处理；结合GEANT4和半实物仿真方法，设计和实现了粒子探测器的半实物仿真系统。.本项目自实施以来，发表SCI/EI论文2篇，会议论文2篇，参与国内学术会议2次，国际学术会议1次，培养毕业硕士研究生2名，正在培养硕士研究生1名，建成TLDAQ样机1套，基于丝网传感器的宇宙线探测系统1套。