基于全反射抑制串扰的双层结构高分辨闪烁屏

High-Resolution Scintillation Screen with Double-Layer Structure Based on Crosstalk Suppression by Interface Total Reflection

在低能X射线成像中,荧光串扰是影响光纤耦合电荷耦合器件(CCD)/互补金属氧化物半导体(CMOS)型高分辨平板探测器空间分辨率的主要因素。基于界面全反射对荧光串扰的抑制作用,提出一种双层结构高分辨闪烁屏。双层闪烁层间通过低折射率耦合介质耦合,调节耦合介质折射率可控制上层闪烁屏与耦合介质界面间可输出的荧光角度,达到抑制荧光串扰、提升闪烁屏探测空间分辨率的目的。基于点扩散函数理论的仿真结果表明,与同等厚度的单层闪烁屏相比,所提双层结构闪烁屏可实现更高的空间分辨率。X射线成像实验结果进一步验证了应用双层结构闪烁屏对提升探测器空间分辨率的有效性。

In lowenergy Xray imaging,fluorescence crosstalk is the most important factor affecting the spatial resolution of fibercoupled highresolution chargecoupled device(CCD)/complementary metaloxidesemiconductor(CMOS)flatpanel detectors.In this paper,a highresolution scintillation screen with a doublelayer structure is proposed on the basis of the suppression effect of interface total reflection on fluorescence crosstalk.The two scintillation layers are coupled by a coupling medium with a small refractive index.The refractive index of the coupling medium can be adjusted to control the output angle of fluorescence on the interface between the upper scintillation screen and the coupling medium,thereby achieving the purpose of suppressing fluorescence crosstalk and improving the spatial resolution detected by scintillation screen.The simulation results based on the point spread function theory show that compared with the singlelayer scintillation screen with the same thickness,the proposed scintillation screen with a doublelayer structure can achieve higher spatial resolution.The experimental results of Xray imaging further verify the effectiveness of the proposed scintillation screen in improving the spatial resolution of the detector.