Luminescent Properties Of Several Metal Ions Doped BaF₂?Eu³⁺ And(Y/Lu)₃Al₅O₁₂:Ce³⁺/Pr³⁺ Scintillation Ceramic Powders

The primary coverage of the thesis is divided into three parts.The first part is about the influence of doping metal ions Li^+,Na⁺,Al³⁺on the luminescent properties of Ba F₂:Eu³⁺;the second part is to analyze the luminescent properties of rare earth ions Ce/Eu co-doped YAG garnet scintillating ceramic powders;and the last part is to explore the effect of adding different flux on the luminescent properties of Lu AG:Pr ³⁺scintillating ceramic precursor powders.The first part:Ba F₂:Eu³⁺ceramic precursor powder and a series of metal ion Li⁺,Na⁺,Al³⁺and Eu³⁺co-doped Ba F₂ ceramic precursor powders were compounded by traditional high temperature solid phase method.Use X-ray diffraction,scanning electron microscopy,photoluminescence spectroscopy and fluorescence decay curve characterization to characterize the microstructure,morphology and luminescence properties of the samples.Excited at 266nm,the experimental results show that the luminescence intensity at 611 nm of Li⁺,Na⁺and Al³⁺samples with a molar concentration of 9%is 4.71 times,1.51 times and 1.35times higher than that of the 23%Eu³⁺sample.The lifetime of the ⁵D₀ level of Eu³⁺after the addition of Li⁺and Al³⁺is prolonged,and the incorporation of Na⁺shortens the energy level of Eu³⁺.Compared to samples without metal ions,the luminescence of 9mol%Li⁺,6mol%Na⁺,23mol%Eu³⁺co-doped Ba F₂ samples and 9mol%Li⁺,12mol%Al³⁺,23mol%Eu³⁺co-doped Ba F₂ samples increased by 1.73 times and3.05 times,respectively,the corresponding energy level lifetime increases.The second part:the Ce³⁺and Eu³⁺co-doped Y₃Al₅O₁₂ scintillation ceramic powders were prepared by the high temperature solid state reaction method.The XRD results showed that all synthesized samples were still the cubic phase of the matrix for Y₃Al₅O1₂.The main peak(420)of all samples shifted to small angles due to the difference in ionic radius.Photoluminescence excitation and emission spectra were employed to study the influence of increasing Eu³⁺concentration on the luminescent property of Ce³⁺and Eu³⁺as well as the energy transfer form Ce³⁺to Eu³⁺.With the increase of Eu³⁺doping concentration,the lifetime of Ce³⁺of the synthesized powders decreased gradually.The lifetime of(Ce_0.01Eu_0.09Y_0.9)₃A1₅O₁₂sample was the shortest,only 4.32ns.Discuss variation of the thermoluminescence curve of the sample with the increase of Eu³⁺incorporation concentration.It also explains the two paths of electron transfer from Ce³⁺to Eu³⁺.The third part:using a high temperature solid phase method to prepare a series of different concentrations of flux Ba F₂ and H₃BO₃ doped into Lu_2.985Al₅O₁₂:0.015Pr³⁺scintillation ceramic powder.The phase structure,luminescent properties and energy level lifetime of the samples were characterized using an X-ray diffractometer and a fluorescence spectrometer.The experimental results show that the incorporation of Ba F₂ and H₃BO₃ does not change the structure of Lu_2.985Al₅O₁₂:0.015Pr³⁺cubic phase.With the increase of Ba F₂ and H₃BO₃ doping amount,the powder luminescence intensity first increases and then decreases,and the Pr³⁺energy level lifetime decreases first and then increases.After annealing at 1600°C for 5h in air,the optimum doping concentration of Ba F₂ and H₃BO₃ is 0.5wt%,and the Lu_2.985Al₅O₁₂:0.015Pr³⁺powder doped with 0.5wt%Ba F₂ is 50%higher than that of the undoped cosolvent sample.The energy level life is reduced to 17.88 ns.The luminescence intensity of the doped 0.5wt%H₃BO₃ was only increased by 20%,and the improvement of the energy level decay time was not obvious.