背景：最近提出的质子治疗中的高剂量率计划以及非常短的质子束可能会给当前的束监测系统带来问题。对具有高时间分辨率的实时质子束监测的需求日益增长，扩展的动态范围和辐射硬度。在这种情况下，耦合到光纤传感器的塑料闪烁体具有很大的潜力，可以成为临床实施的实用解决方案。
目的：在这项工作中，我们评估了非常紧凑的快速塑料闪烁体的功能，该闪烁体具有SiPM和电子传感器的光纤读数，该传感器已用于在临床质子束的纳秒级提供有关时间结构的信息。
方法：耦合到3×3mm2SiPM（MicroFJ-SMA-30035，Onsemi）的3×3×3×3mm3塑料闪烁体（EJ-232QEljenTechnology）的特征是在ProteusOne同步回旋加速器中加速了70MeV临床质子束。通过高采样率示波器(5GS/s)读出信号。通过将传感器直接暴露于质子束，记录单个斑点的时间光束轮廓。
结果:以0.8ns的时间采样周期获得检测器信号的测量值。质子束期(16ns)，在检测器信号幅度的时间曲线中可以观察到斑点（10μs）和斑点间（1ms）时间结构。由此,加速器的射频频率已被提取，被发现是64兆赫。
结论：所提出的系统能够在线测量临床质子加速器的精细时间结构，并具有ns时间分辨率。本文受版权保护。保留所有权利。
BACKGROUND: Recent proposals of high dose rate plans in protontherapy as well as very short proton bunches may pose problems to current beam monitor systems. There is an increasing demand for real-time proton beam monitoring with high temporal resolution, extended dynamic range and radiation hardness. Plastic scintillators coupled to optical fiber sensors have great potential in this context to become a practical solution towards clinical implementation.
OBJECTIVE: In this work, we evaluate the capabilities of a very compact fast plastic scintillator with an optical fiber readout by a SiPM and electronics sensor which has been used to provide information on the time structure at the nanosecond level of a clinical proton beam.
METHODS: A 3 × 3 × 3 mm3 plastic scintillator (EJ-232Q Eljen Technology) coupled to a 3 × 3 mm2 SiPM (MicroFJ-SMA-30035, Onsemi) has been characterized with a 70 MeV clinical proton beam accelerated in a Proteus One synchrocyclotron. The signal was read out by a high sampling rate oscilloscope (5 GS/s). By exposing the sensor directly to the proton beam, the time beam profile of individual spots was recorded.
RESULTS: Measurements of detector signal have been obtained with a time sampling period of 0.8 ns. Proton bunch period (16 ns), spot (10 μs) and interspot (1 ms) time structures could be observed in the time profile of the detector signal amplitude. From this, the RF frequency of the accelerator has been extracted, which is found to be 64 MHz.
CONCLUSIONS: The proposed system was able to measure the fine time structure of a clinical proton accelerator online and with ns time resolution.
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