Preparation And Luminescence Properties Of Rare Earth Ions (Tb³⁺、Eu³⁺、Dy³⁺) Doped TeO₂-B₂O₃-GeO₂ Glass Scintillator

Scintillators are materials that can convert the ionizing radiation energy of high-energy photons or high-energy particles into ultraviolet/visible light emission and are mainly used in medical diagnostic imaging,industrial non-destructive testing,geological detection,security detection,space detection,and other fields.In view of the problems of the high cost of scintillation crystals and high-density scintillation materials in the scintillation field in recent years,glass is considered a material comparable to scintillation crystals because of its obvious advantages of easy chemical composition adjustment,controllable size and shape,good optical uniformity,simple preparation method,and low cost.This thesis focuses on the research of low-cost high density glass that can be used in the scintillation field.By combining the advantages of high-density conventional network formers GeO₂ and TeO₂ with suitable melting points and lower phonon energy,and borogermanates with higher solubility of rare earth,we established TeO₂-B₂O₃-GeO₂ glass as the research object,optimized the glass components and preparation process,explored the influence of Gd₂O₃ concentration on the optimal glass formation range of the matrix glass,and then optimized the glass components and preparation process by adding rare earth oxides（such as Gd₂O₃,Tb₂O₃,Eu₂O₃,Lu₂O₃,and Dy₂O₃）,the effect of different rare-earth ion doping of TeO₂-B₂O₃-GeO₂glasses on the structure and luminescence properties were systematically investigated.The main research contents are as follows:1.The glass-forming range of TeO₂-B₂O₃-GeO₂ matrix glass was prepared and perfected under the air atmosphere by the high-temperature melting method.It was found and proved that the matrix glass has better optical properties and density under high T content of TeO₂ and low concentration of GeO₂.The transmission spectrum,DTA curve,Raman spectrum,and infrared spectrum of TeO₂-B₂O₃-GeO₂ glasses with the different concentrations of Gd₂O₃ were studied.It was found that the addition of Gd₂O₃ improved the network structure of the glass and had better anti-precipitation properties and more stable physical and chemical properties for TeO₂-B₂O₃-GeO₂glasses,and the cut-off edge of the glass is affected by the increase of bridging oxygen bonds and the improvement of the stability of the glass,and the blue shifts to the wavelength of 335 nm,and the glass also changes from dark brown to transparent and colorless.2.The luminescent properties of TeO₂-B₂O₃-GeO₂ glass were studied by the concentration of rare earth luminescent ions and the concentration of glass matrix components.The optimized glass was added to Gd₂O₃ and doped with rare earth luminescent ions.When 7.5 mol%Tb³⁺luminescent ions were added to the B₂O₃-GeO₂-TeO₂-Gd₂O₃ glass composition,the optimal luminous intensity was best,the density was 5.08 g/cm³,the decay time was about 1.328 ms,and the scintillation efficiency measured by X-ray excited emission（XEL）spectroscopy is 9.10%of that of commercial Bismuth Germanate（BGO）crystals.Also,the glass has high irradiation resistance.The luminescence and structural properties of the single-doped B₂O₃-GeO₂-TeO₂-Gd₂O₃-Gd F₃ glass with a concentration of 1mol%Eu³⁺ions with an obvious red luminescence peak were tested.Glass has Ge-O-Ge,B-O-B,Te-O-Te,O-Te-O four vibration units and four coordination forms of BO₃,GeO₄,GeO_6,and BO₄.TheΔT value of this glass is in the range of 159-124°C,and the glass has high stability.3.The luminescence properties of Dy³⁺,Tb³⁺doped,and co-doped B₂O₃-GeO₂-TeO₂ glasses were studied.Various energy transfer processes in the glass have been demonstrated using various luminescence tests.The rare earth oxide Lu₂O₃ was added to the original B₂O₃-GeO₂-TeO₂-Gd₂O₃-Gd F₃ glass composition to increase the density to 5.1 g/cm³.When the two kinds of ions are singly doped,it can be shown that the glass mainly emits the light of the doped ions by studying its luminescence characteristics,and there are energy transfer processes from Gd³⁺to Dy³⁺,Gd³⁺to Tb³⁺,respectively.When co-doped,the luminescence characteristics obtained from the photoluminescence spectrum,decay time curve,and time-resolved luminescence（TRES）spectrum show that Dy³⁺also effectively sensitizes Tb³⁺ions,and with the increase of Tb³⁺concentration,the energy transfer efficiency of Dy³⁺ions to Tb³⁺ions is improved.However,the luminescence properties of Tb³⁺were negatively affected.The XEL intensity of the Tb³⁺ion in the co-doped glass is about 6.4%lower than that of the undoped Dy³⁺ions.Under this glass composition,the optimal scintillation luminescence intensities of Dy³⁺and Tb³⁺ions doped and co-doped B₂O₃-GeO₂-TeO₂-Gd₂O₃ glasses are about 10.45%,41.38%,and 38.73%of those of standard BGO crystals and have a certain degree of radiation resistance.