TRANSIENT TIME SPREAD FUNCTION OF SI-BASED PMT

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 我们建议的项目涉及用于开发飞行时间正电子发射断层成像仪的快速光电探测器的响应特性。 近年来，人们做了大量的工作来了解快速PMT的上升时间和量子效率对它们与快速闪烁晶体耦合时所提供的时间分辨率的影响。所做的大部分工作集中在最基本的探测器--单个小晶体与快速光电倍增管耦合--所提供的定时分辨率的表征和优化上。当这种探测器被平铺以实现大面积覆盖时，正如PET扫描仪或颗粒探测器所要求的那样，与独立探测器相比，测量的定时分辨率显著降低。 我们的调查将试图了解这种时间分辨率下降的来源，并设计一种数据采集和校准方案来将其降至最低。研究的成功将建立光电探测器增益、上升时间、量子效率和信号形状与大面积探测器时间分辨率之间的关系。我们工作的一个主要部分将涉及不同光电探测器的单光子响应的表征以及该响应在光电探测器表面上的变化。这种可变性被怀疑是大面积探测器中定时分辨率下降的主要原因。 这项工作得到了NIH拨款5R01CA113941-02和1R21EB008142-01的支持

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The project we propose involves the characterization of the response of fast photodetectors for the development of Time-Of-Flight Positron Emission Tomography imagers. A good deal of effort has been placed in recent years in understanding the effect of the rise time and quantum efficiency of fast PMTs on the timing resolution they afford when coupled to a fast scintillating crystal. Most of the work done has foccused on the characterization and optimization of the timing resolution afforded by the most basic detector - a single small crystal coupled to a fast PMT. When such detectors are tiled to achieve large area coverage, as is required in a PET scanner or particle detector, the measured timing resolution degrades considerably as compared to the stand alone detector. Our investigation will attempt to understand the source of this degradation in timing resolution, and devise a data acquisition and calibration scheme to minimize it. The successful investigation will establish the correlation between photodetector gain, rise time, quantum efficiency and signal shape and the large area detector timing resolution. A major part of our effort will involve the characterization of the single-photon response of different photodetectors and the variation in that response across the face of the photodetector. This variability is suspected of being greatly responsible for the degradation in timing resolution in a large-area detector. This work is supported by NIH grants 5R01CA113941-02 and 1R21EB008142-01