Meng L J, He Z
Department of Nuclear Engineering and Radiological Sciences, University of Michigan, 1906 Cooley Building, 2355 Bonisteel Blvd., Ann Arbor MI 48109, USA.
IEEE Trans Nucl Sci. 2005 Sep 11;550(1-2):435-445. doi: 10.1016/j.nima.2005.04.076. Epub 2005 Jul 5.
This paper presents a study for exploring the limiting timing resolution that can be achieved with a large volume 3-D position sensitive CZT detector. The interaction timing information was obtained by fitting the measured cathode waveforms to pre-defined waveform models. We compared the results from using several different waveform models. Timing resolutions, of ~9.5 ns for 511 keV full-energy events and ~11.6 ns for all detected events with energy deposition above 250 keV, were achieved with a detailed modeling of the cathode waveform as a function of interaction location and energy deposition. This detailed modeling also allowed us to derive a theoretical lower bound for the error on estimated interaction timing. Both experimental results and theoretical predications matched well, which indicated that the best timing resolution achievable in the 1 cm CZT detector tested is ~10 ns. It is also showed that the correlation between sampled amplitudes in cathode waveforms is an important limiting factor for the achievable timing resolution.
本文介绍了一项关于探索使用大体积三维位置灵敏碲锌镉（CZT）探测器可实现的极限时间分辨率的研究。通过将测量的阴极波形拟合到预定义的波形模型来获取相互作用时间信息。我们比较了使用几种不同波形模型的结果。通过将阴极波形作为相互作用位置和能量沉积的函数进行详细建模，对于511 keV全能量事件，时间分辨率约为9.5 ns，对于能量沉积高于250 keV的所有检测事件，时间分辨率约为11.6 ns。这种详细建模还使我们能够推导出估计相互作用时间误差的理论下限。实验结果和理论预测匹配良好，这表明在所测试的1 cm CZT探测器中可实现的最佳时间分辨率约为10 ns。研究还表明，阴极波形中采样幅度之间的相关性是可实现时间分辨率的一个重要限制因素。
