BES-ⅢTOF子触发系统中高速数据传输的实现

High speed data transferring technology in TOF trigger system of BES-Ⅲ

升级中的北京正负电子对撞机谱仪的飞行时间计数器触发子系统,需进行大量高速数据的吞吐:在41.7MHz的同步时钟控制下从前端读出电子学接收368路快时间击中信号,并向主触发逻辑实时发送4位击中数信息、3位背对背信息,向径迹配对逻辑实时发送136位位置信息,且每16个事例须向DAQ系统提供所有有效事例的数据包,以供离线分析。在该系统的研制中,我们分别或同时利用并串/串并转换、光纤、LVDS、VME总线等不同层面的技术手段实现了不同对象的触发判选信息的传递,本文对此进行了详细介绍。

The TOF （rime-of-fight） trigger system of BES-Ⅲ（Beijing Spectrometer Ⅲ） is faced with the demand of transferring massive high speed data： receiving 368 fast hit signal from the Front-End-Electronics synchronous with the 41.7 MHz dock, sending the processed 4 bits hit number information and 3 bits back-to-back information to the Global-Trigger-Logic with real time, sending processed 136 bits position information to the Track-Match-Logic with real time, and it is desired to provide all the data packet to the DAQ system every 16 valid events, for off-line analysis. During the design, we employed different technical means, such as serialize/de-serialization, fiber, LVDS, VME bus, to achieve the different data transferring requirement. This paper describes the methods we applied in the design.