基于亚表面激光加工技术的微像素位置灵敏型闪烁探测器技术研究

This project firstly focuses on the optical transmissions performances of scintillators such as LYSO, LuAG, and GAGG, which are etched internally using sub-surface laser-engraving processing technique (SSLE). Then according to the requirements of high performance position sensitive detectors, the interaction of laser and scintillators will be researched, and the scintillator processing method will be optimized. The appropriate processing parameters, e.g. the laser intensity, the density of etching, etching layer will be determined, and the scintillator array will be processed. Finally, combined with the photoelectric device of silicon photomultiplier and the special readout electronics, a new position sensitive detector of high spatial resolution (1.0mm) and time resolution (300ps) will be developed. This project could provide the technical basis for PET, SPECT and other radiation imaging system.

针对高性能位置灵敏型探测器的要求，研究经亚表面激光加工技术（SSLE）加工的闪烁体（如LYSO、LuAG和GAGG等）的光传输性能，以及激光和闪烁体的相互作用机制和规律，确定和优化激光强度，蚀刻的密度，蚀刻层等SSLE闪烁体加工参数及加工工艺，制作微像素闪烁体阵列。然后结合硅光电倍增管（SiPM）等新型光电器件，设计专用读出电子学，研制空间分辨优于1.0mm、时间分辨优于300ps的新型高分辨率位置灵敏探测器，为PET、SPECT和其他辐射成像系统提供技术基础。

激光内雕（SSLE）是一种新型的闪烁体加工技术，激光内雕在闪烁体中形成的微爆裂点对闪烁光具有反射作用，可将整块闪烁体加工成像素型阵列，避免了闪烁体像素切割造成的损失，同时也避免了阵列缝隙带来的探测效率损失。本课题研究了激光与闪烁体材料的作用机理、微爆裂点对闪烁光传输的作用，并研究了激光内雕机的激光功率、焦距、脉冲宽度、爆裂点间距等参数对光传输效果的影响；同时尝试了多种常用的闪烁体，筛选出了适合激光内雕的闪烁体以及对应的最优化激光参数；采用激光内雕制作了LYSO阵列，并设计了基于SiPM的读出电子学，得到优于10.5%的能量分辨率以及高精度位置分辨；采用激光内雕制作了基于YSO以及GAGG的3D康普顿相机探测器，获得了良好的成像结果。