GaAs Photomultiplier Chip(TM) for TOF-PET

描述（由申请人提供）：LightSpin Technologies, Inc.提出了一项二期SBIR，以开发一种用于超快TOF-PET应用的新型光电探测器组件（GaAs光电倍增管芯片）。目标是在第二阶段建立一个单光子计时分辨率为50 ps rms的固态光电探测器，在后续工作中建立一个25 ps rms的固态光电探测器。一个25 ps rms的单光子定时抖动将比目前最先进的（用于TOF-PET的光电倍增管和硅光电倍增管器件）要好4倍左右。此外，GaAs光电倍增管芯片将在第二阶段实现25%的量子效率，在后续工作中实现50%的量子效率，进一步提高TOF-PET的时序分辨率（与目前解决方案的10 - 20%量子效率相比）。在第一阶段，我们展示了实现单光子上升速度快至100皮秒的能力。在第二阶段，这些结果将扩展到改进的时序抖动，更高的单光子探测效率和更大的有源区域。这一突破源于LightSpin的创新，该公司将化合物半导体用于单光子探测器，并对单片集成无源猝灭电路进行了优化。由于其更高的迁移率（减少传输时间扩散）和尖锐的雪崩击穿特性（减少雪崩增益过程中的抖动），GaAs固有地比硅更快。第二阶段工作的最终结果将是一个由16mm2光电倍增管芯片组成的88阵列，与圣戈班晶体公司提供的闪烁体阵列相匹配，包括高性能的读出电路和数字化电子设备。超高速TOF-PET应用的性能将由宾夕法尼亚大学的Joel Karp教授进行评估，并与最先进的替代品进行基准测试。第二阶段的目标是演示200 psec的TOF-PET重合时间分辨率，这足够快，可以大幅提高PET在脑和乳腺成像应用中的性能。此外，第二阶段项目预计将为后续工作铺平道路，将符合时间分辨率降低到50秒以下，与目前可用的商用TOF-PET系统相比，提供了一个数量级的改进。

DESCRIPTION (provided by applicant): LightSpin Technologies, Inc., proposes a Phase II SBIR to develop a new photodetector component (the GaAs Photomultiplier Chip") for ultrafast TOF-PET applications. The goal is to build a solid-state photodetector with a single photon timing resolution of 50 ps rms in Phase II and 25 ps rms in a follow-on effort. A single photon timing jitter of 25 ps rms would be about 4 better than the current state-of-the-art (photomultiplier tubes and silicon photomultiplier devices for TOF-PET). Furthermore, the GaAs Photomultiplier Chip" will achieve 25% quantum efficiency in Phase II and 50% in a follow-on effort, further improving the timing resolution in TOF-PET (compared to the 10 - 20% quantum efficiency of today's solutions). In Phase I, we demonstrated the ability to achieve single-photon rise times as fast as 100 picoseconds. In Phase II, these results will be extended to improved timing jitter, higher single photon detection efficiencies, and larger active areas. The breakthrough stems from LightSpin's innovation enabling compound semiconductors to be used for single photon detectors, combined with optimization of the monolithically integrated passive quench circuitry. GaAs is inherently faster than silicon due to its 5 higher mobility (reducing transit time spread) and it sharp avalanche breakdown characteristics (reducing jitter in the avalanche gain process). The end result of the Phase II effort will be an 8 8 array of 16 mm2 Photomultiplier Chips", coupled to a matching array of scintillators provided by Saint-Gobain Crystals and including high performance electrical readout circuitry and digitization electronics. The performance for ultrafast TOF-PET applications will be evaluated by Prof. Joel Karp at the University of Pennsylvania, and benchmarked against state-of-the-art alternatives. The Phase II goal is to demonstrate a TOF-PET coincidence timing resolution of 200 psec, which is sufficiently fast to enable a substantial improvement in PET performance in brain and breast imaging applications. Additionally, the Phase II project is expected to pave the way for a follow-on effort to reduce the coincidence timing resolution to below 50 psec, providing an order of magnitude improvement compared to currently available commercial TOF-PET systems.