Controllable Synthesis Of Cerium Ions Doped Rare Earth Phosphate Scintillators And Their Spectral Properties

Due to the special electronic configuration of trivalent cerium ions,the light-emitting between 5d→4f is electric dipole allowed transition,with nanosecond time of transmission can be used for detection of fast events.The study oftrivalent cerium doped scintillator received widespread attention.Rare earth phosphates matrix material has good chemical stability and thermal stability,and they have been widely used in a variety of light-emitting materials.Among them,the density of lutetium phosphate is bigger as a consequence of lanthanide contraction,and trivalent cerium ions doped lutetium compounds generally have a higher luminous efficiency,high light output.Due to good performance and useful potential of trivalent cerium ion doped lutetium phosphate scintillator,this paper mainly studies the following aspects:(1)Hydrothermal method was used to prepare the cerium ion-doped lutetium phosphate scintillator materials.The fluorescence spectra were tested to obtain the corresponding relationship between the excitation and emission peaks.After adjusting the doping concentration of the scintillator materials and comparing the relative fluorescence emission strength,we can get the best doping concentration of cerium ions.(2)Morphology can influence the performance of the luminescent material.Experimental methods such as hydrothermal method,water bath,heat treatment were used to prepare the granular product,tetrahedron-shaped products,hollow spheres,rods and other structures.With the help of citric acid(CA)as a complexing agent,tetrahedral structure and the rod-like structure precursors can be obtained by regulating the concentration of the phosphate.After heat treatment of the precursor,we can get pure cerium-doped lutetium phosphate scintillator.Tetrahedral precursors having a smooth surface,and the surface of the rod-like precursors present particulate materials.During the heat treatment,the surface of tetragonal precursors become rough,and the rod-like structure precursors maintain their,while the particulate materials disappear.Preparation of structure contains two main steps.At first,spherical Lu(OH)(CO3)2 precursors were prepared by water bath,and then the hollow spherical cerium ion doped lutetium phosphate products were prepared by hydrothermal treatment of spherical precursors.The relative fluorescence emission intensity of the obtained scintillator products with different morphologies was tested.The relative fluorescence emission intensity rod-like structure performs the best.Morphology and surface state of the scintillator materials have a significant impact on the emission intensity.Both the quenching center of the surface and the defects affect the fluorescence intensity.(3)The matrix material significantly affects the energy of 4f-5d level for cerium ions.Trivalent lanthanum,gadolinium,yttrium were doped as matrix material.Trivalent lanthanum,gadolinium,yttrium and lutetium ions having different radii,different electronegativity,and since the lanthanide contraction,lutetium ion has the smallest ionic radius.By adjusting the doping ratio,matrix material with pure phase can be obtained.Change the matrix material will have a significant effect on the fluorescence spectra of cerium ions system scintillator material,the peak excitation and emission peak occurs significantly change of their shape and shift position.At the same time,experiments about adjusting the doping concentration of trivalent cerium ion were carried out.In the lutetium gadolinium matrix composite materials,the optimum doping concentration of cerium ions can be significantly improve,and its luminous intensity was significantly enhanced.When using lutetium yttrium composite matrix material,the emission peaks appear regularly blue shift.