Study On The Optical Properties Of Rare Earth Ion Doped Scintillating Glass-ceramics And Fiber

Scintillator is a kind of energy conversion luminescent material,which can emit ultraviolet light or visible light under the irradiation of X-ray,gamma ray and high-energy particle.At present,inorganic scintillators play an important role in the basic and applied research in the field of radiation detection,and are widely used in high-energy physics experiments,nuclear medical imaging,industrial nondestructive testing,safety inspection,environmental monitoring and exploration,and astronomical observation.Compared with the single crystal,rare earth ion-doped scintillating glass has the advantages of high dopant solubility and easy molding.Especially,glass can be easily drawn into low-loss fibers and further constructed into compact fiber device.However,the physical properties such as density and optical yield need to be further improved.In this thesis,Ce³⁺,Eu²⁺and Tb³⁺doped aluminosilicate fluorosilicate glass and phosphate glass were designed and fabricated.The influences of the types of rare earth ion,the corresponding doping concentration and host glass on the luminescence performance of scintillating glass materials were systematically studied.The colorless Ce³⁺-doped glass with extremely high dopant concentration?15 mol%?,transparent Eu²⁺-doped BaF₂ glass-ceramics with intense blue luminescence and Tb³⁺doped phosphate glass were successfully fabricated.The samples exhibit intense luminescence under excitation with X-ray,indicating their potential applications for radiation detection.The main research results are summarized as follows:1.The colorless Ce³⁺-doped glass with high dopant concentration?15 mol%?was prepared by high temperature melting method.The CeF₃ glass-ceramics were obtained through the heat-treatment process,which is beneficial for increasing the concentration of Ce³⁺and enhancing the luminous efficiency.At the same time,the introduction of F^-significantly changes the local chemical environment around Ce ions,which helps to effectively relieve the self-absorption issue induced by heavy Ce doping,thus improving the luminescence performance of the final glass-ceramics.2.Eu-doped BaF₂ glass-ceramics were prepared by high-temperature melting-quenching and subsequent heat-treatment method.It can be found that with the increase of heat-treatment temperature,the luminescence of sample notably changed and the red and purple luminescence of glass gradually turned into blue under the ultraviolet lamp.The luminescence change can be ascribed to the change of Eu³⁺into Eu²⁺.Based on X-ray diffraction pattern and XPS valence state test,it can be concluded that the precipitation of BaF₂ facilitates the valence state change of Eu dopant.In details,Eu³⁺equivalently replaces Ba²⁺and it changes into Eu²⁺after incorporation into BaF₂ nanocrystals,effectively improving the luminescence properties.3.Phosphate glasses doped with Ce³⁺and Tb³⁺with optimal doping concentration were designed and prepared.Lu³⁺and La³⁺were introduced into the glass matrix to improve the density of scintillating glass.In addition,multi-step treatment with additional reduction atmosphere was adopted to effectively relieve the self-absorption problem induced by high Ce doping concentration and improve the efficiency of X-ray excited luminescence.At the same time,the component glass with the optimal luminous efficiency was selected to fabricate into scintillating glass fiber.The pulse signal can be clearly observed,demonstrating the excellent luminescence performance under X-ray excitation.