Luminescence Properties Of Several Metal Ions And Ce³⁺ Co-Doped Lu₃Al₅O₁₂ Scintillation Ceramic Powders

In this thesis,a series of Lu₃Al₅O₁₂ scintillating ceramic powders co-doped with several metal ions and Ce³⁺were prepared by using the high-temperature solid-phase method.X-ray diffractometer was used to characterize the microstructure of the synthetic powder,the FLS920 steady-state-transient spectrometer was used to measure the sample:excitation,emission spectra,and fluorescence lifetime,and the CIE chromaticity system was used to analyze the color coordinates of the synthetic material.The effects of the synthesis temperature,microscopic crystal phase structure,luminous intensity,energy level lifetime and chromaticity coordinates of Lu₃Al₅O₁₂ scintillating ceramic powders co-doped with several metal ions and Ce³⁺are studied.The specific research content and results of this paper are as follows:The first part of this thesis introduces the general situation of garnet scintillator materials doped with rare earth ions,expounds the basis of the topic selection and research background,and expounds the research content and research innovation points.In the second part of this paper,Gd³⁺and Ce³⁺co-doped Lu₃Al₅O₁₂ scintillating ceramic powders were prepared by high-temperature solid-phase method.The effects of Gd³⁺and Ce³⁺co-doping on the microstructure,luminous intensity,band position,energy level lifetime,luminous color and color coordinates of the synthetic powder were analyzed.The research results show that the sample calcined at 1600℃for 5 h is completely phased,and the co-doping of Gd³⁺and Ce³⁺basically does not affect the cubic phase of the Lu₃Al₅O₁₂ ceramic powder,but as the Gd³⁺doping concentration increases,the diffraction peak of the sample is slightly smaller Angle offset.Under 350 nm excitation,with the increase of Gd³⁺doping concentration,the emission intensity of Ce³⁺near 511 nm decreases,the band is obviously red-shifted,and the lifetime of Ce³⁺decreases gradually.Useλ=254.0 nm orλ=365.0 nm ultraviolet light to irradiate the sample.As the Gd³⁺concentration increases,the luminescent color of the sample gradually changes from dark yellow-green to dark red,and the color coordinates of the sample gradually move from the yellow-green light area to the red light area.In the third part of this thesis,the alkali metal ions Li⁺,Na⁺,K⁺,Cs⁺and Ce³⁺co-doped(Gd_xLu_1-x)₃Al₅O₁₂ scintillating ceramic powder were prepared by the high-temperature solid-phase method.The effects of co-doping of alkali metal ions and Ce³⁺on the microstructure and luminescence properties of the synthesized samples were analyzed.The experimental results show that the doping of alkali metal ions basically does not affect the cubic phase structure of the Lu₃Al₅O₁₂sample.However,with Li⁺doping,the diffraction peak of the sample shifted to a small angle,while Na⁺,K⁺,Cs⁺doping,the diffraction peak of the sample shifted to a large angle.Under excitation at 350 nm,compared with samples without alkali metal ions,the luminescence intensity of the samples was increased by 5.1 times,2.93 times,and 1.79 times after being doped with 2%Li⁺,Na⁺,K⁺and 1%Cs⁺respectively 1.28 times,the life of Ce³⁺is reduced.The sample doped with 2%Li⁺emits brighter underλ=254.0 nm andλ=365.0 nm ultraviolet light.In the fourth part of this paper,some divalent ions Zn²⁺,Mg²⁺,Ca²⁺,Sr²⁺,Ba²⁺and Ce³⁺co-doped Lu₃Al₅O₁₂ scintillating ceramic powders were prepared by high-temperature solid-phase method.The effects of the above divalent ions on the microstructure and luminescence properties are studied.The results show that Zn²⁺,Mg²⁺,Ca²⁺,Sr²⁺,Ba²⁺doping does not affect the cubic crystal phase structure of Lu₃Al₅O₁₂.However,doped with Ca²⁺,Sr²⁺,Ba²⁺,the diffraction peak of the sample shifted to a small angle,and doped with Mg²⁺and Zn²⁺,the diffraction peak of the sample shifted to a large angle.Under 350 nm excitation,the samples doped with0.25%Mg²⁺and 0.25%Zn²⁺,0.5%Mg²⁺,0.5%Zn²⁺,respectively,have a 2.79 times,2.65 times,and 1.78 times higher luminous intensity around 511 nm than the samples without the above ions.And the lifetime of Ce³⁺is reduced.In the end,summarize and look forward to the full text.In the later stage,it is possible to replace other experimental preparation methods,compare the effects of different experimental methods on the synthesized samples,or study the influence of the substitution of other ions in the matrix on the luminescence center.In order to obtain powder with high luminous efficiency and fast attenuation,it also lays the experimental foundation and provides material selection for the preparation of scintillation ceramics with high-performance radiation detection and high-precision imaging in the later stage.