Experimental time resolution limits of modern SiPMs and TOF-PET detectors exploring different scintillators and Cherenkov emission
Experimental time resolution limits of modern SiPMs and TOF-PET detectors exploring different scintillators and Cherenkov emission
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DOI：
10.1088/1361-6560/ab63b4
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发表时间：
2020-01-01
影响因子：
3.5
通讯作者：
Auffray, Etiennette
中科院分区：
文献类型：
--
作者：
Gundacker, Stefan;Turtos, Rosana Martinez;Auffray, Etiennette
硅光电倍增管（SiPM）等固态光电探测器在医学成像、生命科学和高能物理等领域发挥着重要作用。它们能够以低于100 ps的单光子检测时间精度感测光学光子，使其成为在飞行时间正电子发射断层扫描（TOF-PET）中读取快速闪烁器产生的光子的理想候选者。通过实施新型高频读出电子器件，可以对最先进的模拟SiPM和闪烁材料可实现的最佳时序性能进行全新的评估。用Ketek、HPK、FBK、SensL和Broadcom器件测量了SiPM的固有单光子时间分辨率（SPTR）。此外，这些设备的最佳实现的符合时间分辨率（CTR）是用mm（3）和mm（3）尺寸晶体的LSO：Ce：Ca测量的。当照射整个mm（2）或mm（2）区域时，所有器件的固有SPTR范围在70 ps和135 ps FWHM之间。对于所评估的SiPM，具有mm（3）尺寸的LSO：Ce：Ca的所获得的CTR范围在58 ps和76 ps FWHM之间。用来自FBK的现有技术NUV-HD SiPM读出的锗酸铋（BGO）对于mm（3）和mm（3）晶体分别实现了158 ps和277 ps FWHM的CTR。其他BGO几何形状也与Meltmount（n = 1.582）耦合并包裹在Teflon中，对于mm（3）产生167 3 ps FWHM，对于mm（3）产生235 5 ps FWHM。此外，在每个511 keV事件中由BGO产生的切伦科夫光子的平均数量被测量为17 3个光子。基于此测量，我们预测的限制BGO超快定时TOF-PET与蒙特卡罗模拟。还测试了塑料蒸发器（BC 422、BC 418）、BaF 2、与Mg共掺杂的GAGG：Ce和CsI：未掺杂的TOF性能。事实上，BC 422可以实现352 ps FWHM的CTR，仅使用探测器中的康普顿相互作用，最大沉积能量为340 keV。BaF 2具有快速交叉发光，当耦合到来自FBK的VUV-HD SiPM时，能够实现515 ps FWHM的CTR，光子探测效率（PDE）仅为22%。我们总结了测量的CTR的各种放大器，并讨论其固有的时序性能。
Solid state photodetectors like silicon photomultipliers (SiPMs) are playing an important role in several fields of medical imaging, life sciences and high energy physics. They are able to sense optical photons with a single photon detection time precision below 100 ps, making them ideal candidates to read the photons generated by fast scintillators in time of flight positron emission tomography (TOF-PET). By implementing novel high-frequency readout electronics, it is possible to perform a completely new evaluation of the best timing performance achievable with state-of-the-art analog-SiPMs and scintillation materials. The intrinsic SiPM single photon time resolution (SPTR) was measured with Ketek, HPK, FBK, SensL and Broadcom devices. Also, the best achieved coincidence time resolution (CTR) for these devices was measured with LSO:Ce:Ca of mm(3) and mm(3) size crystals. The intrinsic SPTR for all devices ranges between 70 ps and 135 ps FWHM when illuminating the entire mm(2) or mm(2) area. The obtained CTR with LSO:Ce:Ca of mm(3) size ranges between 58 ps and 76 ps FWHM for the SiPMs evaluated. Bismuth Germanate (BGO), read out with state of-the-art NUV-HD SiPMs from FBK, achieved a CTR of 158 ps and 277 ps FWHM for mm(3) and mm(3) crystals, respectively. Other BGO geometries yielded 167 3 ps FWHM for mm(3) and 235 5 ps FWHM for mm(3) also coupled with Meltmount (n = 1.582) and wrapped in Teflon. Additionally, the average number of Cherenkov photons produced by BGO in each 511 keV event was measured to be 17 3 photons. Based on this measurement, we predict the limits of BGO for ultrafast timing in TOF-PET with Monte Carlo simulations. Plastic scintillators (BC422, BC418), BaF2, GAGG:Ce codoped with Mg and CsI:undoped were also tested for TOF performance. Indeed, BC422 can achieve a CTR of 35 2 ps FWHM using only Compton interactions in the detector with a maximum deposited energy of 340 keV. BaF2 with its fast cross-luminescence enables a CTR of 51 5 ps FWHM when coupled to VUV-HD SiPMs from FBK, with only 22% photon detection efficiency (PDE). We summarize the measured CTR of the various scintillators and discuss their intrinsic timing performance.