Fabrication And Properties Of Terbium/Cerium Doped Silicate Glass-ceramics Scintillator

Scintillators,as radiation detection materials,can efficiently detect and rationally utilize high-energy rays and particles,which perform very significiant roles in the fields associated to high-energy radiation,such as medical treatment,security and defense,and high-energy physics.At present,scintillators have been developed for more than 100 years.With the development of science and technology and the upgrading of application scenarios,the requirements for scintillators are becoming progressively strict.Compared with mature single crystal and transparent ceramic scintillators,glass scintillators have the advantages of low cost,large-scale preparation,and the possibility of being fabricated into fibers.However,the contemporary application of glass scintillators is restricted by their low light yield.How to enhance the light yield of glass scintillators has become a significiant research direction.In this work,in order to expand the application scenarios of glass scintillators,several efforts are made to optimize and enhance the light yield of glass material to realize the efficient detection of X-ray and neutrons.First of all,silicate glass is fabricated by melting quenching method.Silicate glass is the glass system with silicon dioxide as the basic composition,which has good chemical stability,strong glass-forming performance,and superior processing performance.In addition,nemerous studies have found that silicate glass has better scintillation performance than other glass systems.Then,the scintillation performance of silicate glasses are effectively improved by forming glass-ceramics via heat treatment,which lead to the construction of a crystal environment within the glasses.Finally,Tb³⁺and Ce³⁺rare earth ions both have excellent luminescence characteristics and fulfill the requirements of radiation detection device,which are excellent selection of luminescence centers to enhance the luminescence performance of glass scintillators.The main works are as follows:（1）Na₃Y_（1-x）Tb_xSi₃O₉ glass-ceramics with superior scintillation and luminescence properties were prepared by heat treatment,and crystals inside the glass enhenced the electron-hole pair migration efficiency and luminescence efficiency.By altering the ratio of Y/Tb in the components,the structure of the glass matrix is regulated,which impacts the structural change during heat treatment.The temperature of the heat treatment was adjusted to regulate the crystal morphology of glass-ceramics,which further influences their optical properties and scintillation properties.The integral intensity of the sample with the best scintillation properties can reach5.2 times that of Bi₄Ge₃O₁₂,a commercial scintillation crystal.After screening the material for two crucial properties,optical transparency and scintillation properties,a suitable glass-ceramic was picked to illustrate the X-ray imaging trial,which demonstrated the application potential of the material in X-ray imaging.（2）Based on the excellent scintillation performance of commercial Lu₃Al₅O₁₂:Ce single crystal,high density Lu₃Al₅O₁₂:Ce glass-ceramics were prepared.By adapting the preparation technology and the composition regulation,precursor glasses with the content of Lu₂O₃ and Gd₂O₃ of 41.5 and 8.5 mol%respectively,were successfully prepared,and the Lu₃Al₅O₁₂:Ce crystals were successfully precipitated in the glass by heat treatment.After enhancing the scintillation properties of the glass-ceramics by optimizing the substrate composition and Ce doping concentration,the integral intensity of X-ray induced luminescence of the sample with the best scintillation performance is 1.85 times that of the commercial Bi₄Ge₃O₁₂ scintillation crystal,and its lifetime is 48.4 ns.Lu₃Al₅O₁₂:Ce glass-ceramics with excellent scintillation performance may be used in radiation detection instead of Lu₃Al₅O₁₂:Ce crystal in some cases.（3）Based on the component of commercial glass scintillators,the Li Al Si O₄ and Li Al Si₂O₆glass-ceramics with high contents of Li and without devitrification after heat-treatment were prepared after adaption of the component proportion.The crystallization process of glass-ceramics was regulated by a two-step heat treatment,and the influence of different holding time on the structure and properties of the materials was researched.The experimental results reveal that both Li Al Si O₄ and Li Al Si₂O₆ glasses can detect thermal neutrons,and their light yields are68.6%and 91.4%of that of commercial lithium glass,respectively.（4）Through the hybrid engineering of oxide and fluoride,the formation and crystallization of sodium alumina silicate glass were regulated and optimized,and the transparent Na Al Si O₄glass-ceramics with full crystallization were prepared.The optical properties and scintillation properties of Na Al Si O₄ glass-ceramics were optimized by investigating different heat treatment temperatures.After proper heat treatment,Na Al Si O₄ glass-ceramics with dense polycrystal structures can be obtained.It is found that the Na Al Si O₄ glass-ceramic can achieve efficient detection of X-ray,αparticles,and thermal neutrons.In addition,the experimental results show that the light yields Na Al Si O₄ glass-ceramic is 104%of that of commercial lithium glass,showing it is a new material with potential application in thermal neutron detection.