一种基于SiPM的新型起始时间探测器研制

本文介绍了一种新型起始时间探测器的研制。该探测器的灵敏面积为60 mm×60 mm，利用120根直径为1 mm的塑料闪烁光纤分成两层错位紧致排布，且上下相邻的3根光纤作为一个探测单元，每个探测单元均采用硅光电倍增管从双端读出信号。采用90Sr放射源对单根光纤进行了性能测试，结果表明，闪烁光沿着光纤方向的有效传播速度约为17 cm/ns，对应的时间分辨优于600 ps。此外，利用中国科学院近代物理研究所第二条放射性束流线（RIBLL2）提供的240 MeV/u的15N次级束研究了该探测器的性能。束流测试结果表明:该探测器的时间分辨为（150±15）ps，纵向位置分辨为（1.8±0.2）cm，并且结合该探测器以及RIBLL2束流线外靶实验终端上的其他探测器，可以对实验中产生的5 ≤ Z ≤ 8的各种同位素进行非常好的粒子鉴别。

Development of a New-typed Start-time Detector Based on SiPM

In this paper, a new type of start-time detector is developed. The sensitive area of the detector is 60 mm×60 mm, which is divided into two layers of dislocation tightly arranged by 120 plastic scintillating fibers with a diameter of 1mm, and three adjacent fibers are used as one detecting unit that uses the silicon phtotmultiplier to read signals. The work uses 90Sr radiation source to test the performance of a single scintillating fiber, the results show that the propagation speed of light in the fiber is about 17 cm/ns, and the corresponding time resolution is better than 600 ps. Besides the test using 90Sr source, the detector's performance has also been inspected through the 15N secondary beam of 240 MeV/u provided by the second radioactive beam line at Lanzhou (RIBLL2) of Institute of Modern Physics, Chinese Academy of Sciences. The in-beam test results show that the time resolution and vertical position resolution of the detector are (150±15) ps and (1.8±0.2) cm respectively. Combined with the detector and other detectors on the RIBLL2 External Target Facility, various isotope particles of 5 ≤ Z ≤ 8 generated in the experiment can be well identified.