Compositional regulation of multi-component GYGAG:Ce scintillation ceramics:Self-sintering-aid effect and afterglow suppression

(Gd,Y,Ce)_(3)(Y_(x)Ga_(1−x))_(2)GaAl_(2)O_(12)(GYGAG:Ce)scintillation ceramics with different Y excess,where x=0.005−0.08,were fabricated by the solid-state reaction method.The effects of stoichiometry on the phase composition,optical quality,and microstructure of GYGAG:Ce ceramics were analyzed.GYGAG:Ce ceramics have a pure garnet phase and obtain good in-line transmittance when x<0.04,while more Y excess leads to the creation of the secondary phase.The change of x value influences the sintering behavior of the GYGAG:Ce ceramics:The excess of Y works as the self-sintering aid and significantly reduces the sintering temperature of ceramics.When x=0.01–0.04,the X-ray excited luminescence(XEL)spectra and light yields of GYGAG:Ce ceramics are similar.The fast scintillation decay time and afterglow intensity of GYGAG:Ce ceramics show a slight decrease with increasing x value.Finally,additional 50–500 ppm MgO and 100–500 ppm CaO were introduced to the GYGAG:Ce ceramic with x=0.04,and both were found to significantly increase the fast scintillation component and reduce the afterglow intensity by two orders of magnitude to 0.01%after X-ray cut-off.

Sr2Mg1-xCaxSi2O7:Eu^2+,Dy^3+蓝色长余辉发光材料的合成及余辉性能调控

为了调控长余辉发光材料的余辉寿命,利用Ca^2+对长余辉材料基质中的Mg^2+进行不同程度取代,即通过高温固相法制备了一系列Sr2Mg1-xCaxSi2O7:Eu^2+,Dy^3+(x=0, 0.2, 0.4, 0.6, 0.8, 1.0)长余辉发光材料。通过高温固相法制备的样品相较于溶胶-凝胶法所得样品具有更好的晶体结构,发光性能也更好。X射线衍射结果表明,随着原料中Ca^2+含量的增加,合成样品的衍射峰逐渐往高角度移动,表明该基质内Ca^2+已经取代Mg^2+的晶格位置,使晶格发生变化,晶体场发生改变。样品发射峰位于487~492 nm,为蓝色发光材料。通过观察余辉衰减图和初始余辉亮度值可知,随着Ca^2+含量的增加,样品的余辉衰减寿命和发光强度逐渐减小。以上性质有望使该材料在需要短寿命余辉产品领域有新的应用前景。