Lee Seungeun, Choong Woon-Seng, Heller Ryan, Cates Joshua W
Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA.
IEEE Trans Radiat Plasma Med Sci. 2025 Apr;9(4):406-411. doi: 10.1109/trpms.2024.3518479. Epub 2024 Dec 16.
Single photon time resolution (SPTR), photon detection efficiency (PDE), and correlated noise rate are important performance characteristics of modern silicon photomultipliers (SiPMs) in consideration of advances in time-of-flight positron emission tomography (TOF-PET). Commercially available Broadcom near-ultra-violet metal-trench (NUV-MT) SiPMs feature metal-filled trench technology to suppress optical crosstalk. We investigated the achievable SPTR and coincidence time resolution (CTR) of NUV-MT SiPMs with various sizes and scintillation crystals, employing low-noise high-frequency readout electronics. The achievable intrinsic SPTRs of 2×2, 4×4, and 6×6 mm devices were estimated using a picosecond-pulse laser setup. 2- and 4-mm SiPMs were coupled with 2×2×3 mm and 3×3×20 mm LGSO and BGO crystals to assess achievable CTRs. The intrinsic SPTRs of 2-, 4-, and 6-mm SiPMs biased with 48 V were estimated to be 45, 55, and 137 ps in full-width at half-maximum (FWHM), respectively. The detector comprised a 2-mm SiPM and a 2×2×3 mm BGO achieved 111 ps CTR FWHM. The results demonstrated a significant influence of superior SPTR of 2-mm SiPM for the Cherenkov event portion compared to scintillation-based events. The suppressed noise of NUV-MT enabled stable operation at high bias voltage, offering excellent SPTR and PDE for breakthroughs in the timing resolution of TOF-PET detectors.
考虑到飞行时间正电子发射断层扫描(TOF-PET)的进展,单光子时间分辨率(SPTR)、光子探测效率(PDE)和相关噪声率是现代硅光电倍增管(SiPM)的重要性能特征。市售的博通近紫外金属沟槽(NUV-MT)SiPM采用金属填充沟槽技术来抑制光学串扰。我们采用低噪声高频读出电子设备,研究了不同尺寸和闪烁晶体的NUV-MT SiPM可实现的SPTR和符合时间分辨率(CTR)。使用皮秒脉冲激光装置估计了2×2、4×4和6×6 mm器件可实现的固有SPTR。将2 mm和4 mm的SiPM与2×2×3 mm和3×3×20 mm的LGSO和BGO晶体耦合,以评估可实现的CTR。偏置电压为48 V的2 mm、4 mm和6 mm SiPM的固有SPTR在半高宽(FWHM)下分别估计为45、55和137 ps。由一个2 mm的SiPM和一个2×2×3 mm的BGO组成的探测器实现了111 ps的CTR FWHM。结果表明,与基于闪烁的事件相比,2 mm SiPM的优异SPTR对切伦科夫事件部分有显著影响。NUV-MT的噪声抑制使其能够在高偏置电压下稳定运行,为TOF-PET探测器的时间分辨率突破提供了优异的SPTR和PDE。