The Hydrothermal Synthesis And Characteristics Of BaHfO₃:Ce Scintillator Ultramicron

Recently, ceramic scintillators are widely used in the fields of high energy physics, nuclear physics, the nuclear medicine, industrial inspection, especially in nuclear medicine field. Probe which is constituted with scintillator and photomuitplier is the key part of the nuclear medical imaging device. However, currently the properties of scintillating materials are different from on to the others. Therefore, the study will be focus on developing an idea scintillating materials. BaHfO3:Ce has fast primary speed, high light output and high X-ray stopping power,which makes it become an important material of scintillating material.In this dissertation, the preparation technology and properties of BaHfO3:Ce powders were studied systematically. BaHfO3:Ce powders were prepared by hydrothermal and C2H5OH/H2O mixed solvothermal methods. The parameters were optimized by XRD and SEM which characterized the phase transformation, morphology characteristics, particle size and crystallinity of BaHfO3:Ce powders, and the photoluminescence properties of powders were characterized by fluorophotometer as well.The BaHfO3:Ce powders with 0.5μm particle size and granatohedron morphology were synthesized by hydrothermal method while the mol ratio of Ba/Hf is 1:1, the pH value is 13.5, the temperature of hydrothermal is 200℃and soaking time is 24 hours.The BaHfO3:Ce powders, which had about 50 nm particle size and subsphaeroidal were synthesized by C2H5OH/H2O mixed solvothermal method with V(C2H5OH):V(H2O)=5:1. Adjusting the solvent ratio and pH value can prepare different morphologies of powders. When the pH value is lower than the 13.5, the powder is serious agglomeration with bad morphology. However, when the pH value is 13.5, the morphology of powders was sphere, and the powders dispersal well. The dopant of Ce3+had no effect on the crystal structure of the powders. When the Ce3+ dopant content was 0.3mol%(molar fraction), emission intensity of BaHfO3:Ce powders was best. When the the Ce3+dopant content is above 0.3mol%(molar fraction), concentration quenching was occurred. BaHfO3:Ce powders have two wide excitation spectra among 360 and 420 nm, and among 430 and 445 nm With peaks of 393 and 445 run respectively. The excitation peaks were caused by the 2F5/2→5d and 2F7/2→5d electric transition of Ce3+ cations. When the emission spectrums were excited by the 393 and 446 nm light, there are two wide emission spectra which were originatied from 5d→2F5/2 and 5d→2F7/2 transition.