Study On Growth And Scintillation Properties Of KSr₂I₅:Eu Single Crystals

KSr₂I₅:Eu scintillation crystal has a monoclinic structure with space group P12₁/c1 and a density of 4.39g/cm³.As a new ternary alkali metal halide scintillator,potassium strontium iodide,activated with divalent europium(KSr₂I₅:Eu²⁺)possesses higher light yield,a more wide range of linear response and superior energy resolution,which make it become the fourth inorganic ions scintillation crystals with energy resolution below 3%after LaBr₃:Ce,SrI₂:Eu and CsBa₂I₅:Eu in scintillation crystal history of research.The eminent scintillation properties make it have a vitally important application value and foreground in the field of nuclear nonproliferation detection,gamma ray detection and nuclear medical imaging.Meanwhile,KSr₂I₅:Eu also has a very low melting point of 470?that other three kind of crystal don't have.In addition to this,it has pretty fast growth rate,its growth rate has five time as the SrI₂:Eu at least.These properties make it have quite obvious industrial advantage in the field of crystal growth and contribute to industrialization production.As a consequence,KSr₂I₅:Eu is a new kind of scintillation crystal which has great potential.The research on KSr₂I₅:Eu has just started in the domestic and overseas by far,which shows KSr₂I₅:Eu crystal has very high research significance and practical value.Therefore,this paper has carried out the KSr₂I₅:Eu crystal research work on crystal growth and scintillation properties.The main research content includes two parts:for one part,in order to get the most suitable growth conditions and optimum technological parameter for high quality and large size crystal,a long time experiment grope containing lots of work have been done;For another part,a comprehensive testing and study of crystal scintillation performance as well as potential application analysis have been fiished.Main research results of this study can be generalized as follows:?1?Potassium strontium iodide,activated with divalent europium(KSr₂I₅:0.5%Eu²⁺)was successfully grown via the Bridgman method and spontaneous nucleation.The dimension of crystal blank has a length of 30mm.Also successfully obtained KSr₂I₅single crystal machined has sizes up to 15 mm×10 mm×10 mm which has no obvious macroscopic defects through processing and polishing.?2?We acquired the optimum growth conditions for KSr₂I₅:Eu single crystal within the scope of this research:The bottom of quartz crucible lower 1cm than temperature gradient zone,controlling temperature should be set at 530?,temperature gradient was about 15²5?/cm in growing zone,quartz crucible descent rate was 0.4mm/h.?3?Through the analysis of the fluorescence spectrum of the crystals,we found that KSr₂I₅:0.5%Eu single crystal has a single peak at about 445 nm,which dues to the typical 5d–4f transition in Eu²⁺.Meanwhile,we find some overlap between excitation and emission peaks,which indicates this kind of crystal has a certain self absorption.?4?The X-ray excitation emission spectrum of the crystal indicate that the crystal has a single peak at about 445 nm,which dues to the typical 5d–4f transition in Eu²⁺,this result in accordance with fluorescence spectrum,the quantum efficiency of the crystal was 12.2%with PMTR1306.?5?The light yield was 1.2 to 1.3 times than the LYSO,energy resolution was 6.8%of KSr₂I₅:Eu single crystal excited by ¹³⁷Cs gamma rays separately,which manifests that the crystal is extremely potential new scintillation crystal.