Research On X-ray Scintillation Screen Based On Macroporous Silicon

The traditional thin film crystal columnar X-ray scintillation screen has the problem of light crosstalk.Reducing the thickness can improve the resolution,but its detection efficiency cannot be ensured.X-ray scintillation screens based on macroporous silicon can not only solve the problem of light crosstalk,but also ensure its thickness and further improve the flicker performance.Therefore,such X-ray scintillation screens have become the mainstream of related researches.And this thesis focuses on the technical research of X-ray scintillation screen performance.Macroporous silicon substrates were prepared by lithography,ICP etching,silicon photoelectrochemical etching,shaping,oxidation and other processes.The vacuum melting filling method was used to fill the Cs I(Tl)deep hole array,which was used as scintillation screen after polishing.Observing the cross-section SEM image of the scintillation screen,it was found that the scintillation screen was well filled.With 200 ?m depth of the Cs I(Tl)scintillation column,only a small amount of gas was filled at the bottom.After the researches of the effect of polishing pad material on the scintillation screen,and the comparison of two polishing methods,namely upside down and upside down.The results show that the upside down polishing method can improve the degree of surface finish of the scintillation screen and the completeness of the crystal pillar structure of the channel.XRD characterization of scintillation screens with different Tl+ concentrations was conducted,and X-ray diffraction patterns of scintillation screens were analyzed.It was found that the peak of X-ray diffraction patterns of scintillation screens would shift with the increase of Tl+ concentrations.An X-ray imaging system was set up,the brightness of the X-ray imaging image of the scintillation screen was increased by using the camera and increasing the exposure time.X-ray imaging images of scintillation screens with different Tl+ concentrations were obtained.Matlab software was used to process and analyze the imaging images.It was found that when the concentration of Tl+ was 0.09 mol%,the brightness was the highest.And with the increase of Tl+ concentration,the brightness increased first and then decreased.The X-ray excitation emission spectrum of the scintillation screen was analyzed.It was found that when the concentration of Tl+ was 0.09 mol%,the relative luminescence intensity was the highest,which was consistent with the results of the X-ray imaging map.Moreover,it was found that the luminescence peak of the X-ray excitation emission spectrum moved slightly to the right with the increase of the concentration of Tl+.By using the established X-ray imaging testing system and changing the energy and imaging time of the X-ray,X-ray imaging images of the scintillation screen based on macroporous silicon with different thickness were obtained.Matlab software was used to analyze the images,and it was found that the brightness of the images increased with the increase of the thickness of the scintillation screen...