| Scintillating ceramics are widely used in medical,military,geological exploration and other fields to detect high-energy particle or high-energy ray.Understanding and exploration in a deeper level of how to improve the photo-luminescence properties of scintillators are of great value.The preparation and synthesis of ceramic powders is the first step in the preparation process of scintillating materials which is considered to be of the greatest significance as well,scintillation properties of scintillators such as light-yield,decay-time and resistance to radiation are considerably influenced by the quality and performance of scintillating powders.This thesis focuses on multiple rare earth ions doping system:Pr,Ce:YAG,series of experiments research which are of considerable quantities are practiced to investigate how to prepare and synthesis scintillating ceramic powders with ideal grain size,homogeneous spatial distribution,sound photo-luminescence performances utilizing chemical co-precipitation method.Analysis on factors in every synthesis step is approached by contrast experimental research in order to develop the exploration of the optimization of preparation technology.The thesis studies on influence of preparation parameters of chemical co-precipitation method,compositions of raw reaction material,introduction of organic alcohol etc to particle size,phase formation,photo-luminescence properties of precursors and ceramic powders characterized by X-ray diffraction apparatus(XRD),field emission scanning electron microscopy(FESEM),laser particle size analyzer,fluorescence spectrophotometer etc The main research contents are divided into aspects as followed:(1)Analysis of process parameters on chemical co-precipitation method is proceeded by contrast experiments,including main process parameters:calcination temperature,calcination time,drying method,washing water temperature,aging time,titration,pH value;Reverse feeding method,precipitation solution with pH value at 9.5 regulated by ammonium hydroxide,microwave drying method,temperature of washing water monitored at 30℃-50℃,24h aging time,calcination at 1050℃ for 4h,preparation parameters above are confirmed to contribute to Pr,Ce:YAG ceramic powder with 70nm approximately grain size and sound spatial distribution;(2)Analysis and research on compositions of raw reaction materials is conducted by contrast experiments,main compositions include:precipitation solution type,precipitation solution concentration,mixed cation concentration,mixed cation temperature;precipitation solution of ammonium hydroxide and ammonium acid carbonate with 1:1 ration of substance amount,1.0mol/L precipitation solution concentration and mixed cation solution concentration,40℃ approximately mixed cation solution temperature,conditions above are confirmed to be beneficial and contributing for characteristic radiation transition of Pr3+and Ce3+under variation scope studied in the thesis.(3)The research of the thesis explored out an optimum series of preparation parameters within certain variation ranges,through the introduction of glycerol and,determine the best introduction amount improved the Pr,grain size and luminescence properties of Pr,Ce:YAG ceramic powder.Study and analysis on the impact conducted by introduction of polyethylene glycol(PEG),glycerin and oxalic acid on micro-structure,phase formation process and photoluminescence properties is approached.Both of PEG and glycerin have affirmative influence on homogeneous distribution and formation of pure YAG phase.Controlling substance amount ratio between oxalic acid and total substance amount of rare earth ion and volume ratio between glycerin and deionized water to 3:1 and 1:20 respectively is confirmed to be contributing to emission intensity of 5d-4f characteristic radiation transition of Ce3+.This thesis studies and explores series of optimized preparation parameters within certain variation ranges,the correlation between microstructure,photoluminescence performance of Pr,Ce:YAG scintillating ceramics and the introduction of glycerin and oxalic acid is investigated. |
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