用于CSR外靶实验终端高时间分辨起始时间探测器的研制

The resolution of Time-of-Flight is one of the most important roles in particle identifications(PID) at ETF of CSR-RIBLLII.The start detector at ETF is a key detector for PID upstream and downstream the secondry target at ETF. The previous start detectors are no longer meet all requirements in nuclear physics experiments for their poor time resolutions as well as other reasons.A scintillating fibre detetor, which is readout by a new typed photoeletric device multi-anode MCP-PMT,will be developed for various heavy ions(2≤Z≤92）produced or provided by RIBLLII. This scintillating fibre detector can be used to magnetic and irradiation enviroment. The detector will obatain the secondary beam strcture and reach a time resolution of 40 ps and work well at count rates of up to 106, and the position resolution parallel to the fibre is found to be 0.75 mm.A detailed studies will be applied to scintillating fibre and multi-anode MCP-PMT, including their types,dimendions,coating, proper work voltage and absolute light production,ete.al, also to the readout electronics to obain the best time resolution. A beam test will be implemented to verify the performance of the new typed detector.

在CSR-RIBLLII外靶实验终端，飞行时间（ToF）分辨是影响核素鉴别最为关键的因素。外靶实验终端的起始时间探测器是次级靶前和次级靶后粒子鉴别的关键探测器，原有的设计方案已经不能满足日益丰富的实验需求。本项目拟选择塑料闪烁光纤作为探测器介质材料，一种新型的光敏元器件多阳极微通道板光倍管（MCP-PMT）作为读出器件，新研制一种起始时间探测器，可以工作于磁场和辐照环境，预计该探测器时间分辨好于40 ps，沿着光纤方向位置分辨好于0.75mm，能够承受106/pps的计数率，能够测量束斑结构，并能实现RIBLLII提供的所有重离子核素（2≤Z≤92）的鉴别。通过对闪烁光纤和多阳极MCP-PMT型号、尺寸、工艺、工作条件、绝对光产额与时间分辨的依赖曲线及读出电子学对时间分辨的细致研究，确定最为优化的探测器组合和电子学读出方案，最后通过束流实验验证新型起始时间探测器的性能。

在CSR-RIBLLII外靶实验终端，飞行时间（ToF）的分辨是影响放射性核素鉴别最为关键的因素。外靶实验终端的起始时间探测器是次级靶前和次级靶后ToF鉴别的关键探测器，原有的设计方案由于时间分辨较差且不能实现束斑位置及大小的等的测量，需要采用新的技术进行重新研制。本项目选择了塑料闪烁光纤作为探测器介质材料，一种新型的光敏元件硅光倍管作为读出器件，重新研制了外靶实验终端的起始时间探测器。在项目执行过程中，通过对元器件的性能测试、单元样机的测试、探测器工艺的摸索、探测器总体物理的设计和装配及总体读出电子学的方案设计，最终研制了满足终端起始时间探测器高时间、位置及计数率的要求，并最终通过束流试验初步验证了探测器的性能，可以很好的工作于外靶实验终端。因此，本项目基本完成了预期目标。