In view of its importance to applications in high-energy physics, nuclear security, and time-of-flight positron emission tomography (TOF-PET), the time resolution of 0.5% benzophenone-quenched EJ-232Q plastic scintillators of various lengths was studied using a fast waveform digitizer and fast photomultiplier tubes (PMTs). The scintillator sizes were 5 mm $\times 5$ mm $\times10$ , 25, 50, 75, or 100 mm. First, the timing measurements were performed by using a single PMT reading out one end. The degradation in time resolution with increasing scintillator length was studied. The irradiation geometry was also observed to have a nonnegligible impact on the time resolution due to the variation of depth-of-interaction (DOI) positions, especially for the scintillators with a high aspect ratio. Second, two PMTs were employed for a dual-sided readout. This readout together with the mean time method was demonstrated to be an effective approach to improve the timing performance since the DOI-related effect was considerably mitigated. A time resolution of 79 ± 1 ps (full-width at half-maximum) has been achieved for the $5 \times 5 \times 10$ mm³ scintillator. The $5\times 5\,\,\times100$ mm³ scintillator can still provide a time resolution as good as 172 ± 1 ps. The energy range used for each was between 340 and 450 keVee. In addition, the time information from individual PMTs in a dual-sided readout was able to show a time resolution almost identical to that determined with the mean-time-based technique after correcting for the DOI variation for the 100-mm-long scintillator.

中文翻译：

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具有单面和双面读数的 EJ-232Q 的时间分辨率测量

鉴于其在高能物理、核安全和飞行时间正电子发射断层扫描 (TOF-PET) 应用中的重要性，研究了 0.5% 二苯甲酮淬火的 EJ-232Q 各种长度塑料闪烁体的时间分辨率使用快速波形数字化仪和快速光电倍增管 (PMT)。闪烁体尺寸为 5 mm $\times 5$ 毫米 $\times10$ 、25、50、75 或 100 毫米。首先，通过使用单个 PMT 读出一端来执行定时测量。研究了随着闪烁体长度的增加时间分辨率的降低。由于相互作用深度（DOI）位置的变化，特别是对于具有高纵横比的闪烁体，还观察到辐照几何形状对时间分辨率的影响不可忽视。其次，采用两个 PMT 进行双面读出。这种读数与平均时间方法一起被证明是提高计时性能的有效方法，因为与 DOI 相关的影响已大大减轻。已实现 79 ± 1 ps（半高全宽）的时间分辨率 $5 \times 5 \times 10$ mm ³闪烁体。这 $5\times 5\,\,\times100$ mm ³闪烁体仍可提供高达 172 ± 1 ps 的时间分辨率。每个使用的能量范围在 340 到 450 keVee 之间。此外，在对 100 毫米长闪烁体的 DOI 变化进行校正后，双面读数中来自单个 PMT 的时间信息能够显示出几乎与使用基于平均时间的技术确定的时间分辨率相同的时间分辨率。