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

In low-energy X-ray imaging, fluorescence crosstalk is the most important factor affecting the spatial resolution of fiber- coupled high-resolution charge-coupled device ( CCD)/complementary metal-oxide-semiconductor (CMOS) flatpanel detectors. In this paper, a high-resolution scintillation screen with a double- layer 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 single-layer scintillation screen with the same thickness, the proposed scintillation screen with a double- layer structure can achieve higher spatial resolution. The experimental results of X-ray imaging further verify the effectiveness of the proposed scintillation screen in improving the spatial resolution of the detector.