Department of Biomedical Engineering, University of California Davis, Davis, CA, United States of America. Author to whom correspondence should be addressed.
Phys Med Biol. 2019 Aug 28;64(17):175001. doi: 10.1088/1361-6560/ab35c4.
Thallium bromide (TlBr) is a semiconductor material and, simultaneously, a good Cerenkov radiator. The performance of a TlBr detector that integrates two different readouts, the charge induction readout and the detection of Cerenkov light, was evaluated. A TlBr detector with dimensions of 4 × 4 × 5 mm, with a monolithic cathode and an anode segmented into strips, was manufactured. One of the bare and polished 4 × 4 mm faces of the detector was coupled to a silicon photomultiplier (SiPM) to read out the Cerenkov light. Simultaneous timing and energy resolutions of <400 ps full width at half maximum (FWHM) and ~8.5% at 511 keV were measured using the Cerenkov detection and charge induction readouts, respectively. A coincidence time resolution of 330 ps was obtained when selecting Cerenkov events with amplitudes above 70 mV. The combination of both readouts showed the potential to resolve the depth-of-interaction (DOI) positioning, based on the improvement of energy resolution when selecting events with similar electron drift times. This manuscript sets the stage for a new family of semiconductor detectors that combine charge induction readout with the Cerenkov light detection. Such detectors can provide, simultaneously, outstanding timing, energy, and spatial resolution, and will be an excellent fit for applications that require the detection of high-energy gamma photons with high timing accuracy, such as time-of-flight positron emission tomography (TOF-PET) and prompt gamma imaging (PGI) to assess the particle range in hadron therapy.
溴化铊（TlBr）是一种半导体材料，同时也是一种良好的切伦科夫辐射体。评估了一种集成两种不同读出方式的 TlBr 探测器的性能，这两种读出方式分别是电荷感应读出和切伦科夫光探测。制造了一个尺寸为 4×4×5mm 的 TlBr 探测器，具有整体阴极和分段阳极。探测器的一个裸露和抛光的 4×4mm 面与硅光电倍增管（SiPM）耦合，用于读取切伦科夫光。使用切伦科夫探测和电荷感应读出，分别测量到<400ps 全宽半最大值（FWHM）和~8.5%的 511keV 时的时间和能量分辨率。当选择幅度大于 70mV 的切伦科夫事件时，获得了 330ps 的符合时间分辨率。当选择具有相似电子漂移时间的事件时，两种读出方式的组合显示出具有改善能量分辨率的潜力，从而实现了相互作用深度（DOI）定位。本文为一种新型半导体探测器奠定了基础，该探测器将电荷感应读出与切伦科夫光探测相结合。这种探测器可以同时提供出色的时间、能量和空间分辨率，非常适合需要高时间精度检测高能伽马光子的应用，例如飞行时间正电子发射断层扫描（TOF-PET）和瞬发伽马成像（PGI），以评估粒子在强子治疗中的射程。
