Preparation And Optical Property Of Dy³⁺ Doped C12A7 Phosphors For X-ray Imaging Storage

In recent years,due to the static and dynamic digital X-ray image target detection technologies applied in medical and industrial field,the X-ray fluorescent powder materials on the system imaging board was paid more and more attention by people.The quality of static X-ray imaging mainly depends on X-ray storage characteristics of X-ray fluorescence powder,such as lighting the excitation,X-ray imaging and so on.At present,the BaFBr:Eu²⁺and other rare earth ions doped halide were mainly the commercial X-ray phosphor.Although the fluorescent powder has high luminescence intensity,sensitivity and conversion efficiency,but it is easy to contaminate the environment during the preparation process,and the thermal stability and chemical stability are poor.However,the above shortcomings are overcomed by the rare earth ion doped oxide X-ray phosphor,and how to improve the X-ray storage characteristics is the mainly research focus.In this paper,C12A7:Dy³⁺X-ray fluorescence powder was prepared,whose luminescence properties and X-ray storage characteristics were studied.In this paper,C12A7:Dy³⁺materials with different doping concentrations were synthesized by self-propagating combustion method.The XRD spectrum indicated that the C12A7 powder samples with different concentrations of dysprosium were pure phase under the condition that the concentration of dysprosium was less than or equal to 0.8%.And the emission spectrum also indicated that,the intensity of the blue and yellow light emission of the sample was the largest in 0.3%dysprosium,From the afterglow curve and photostimulable luminescence curve,it was found that when the dysprosium doping concentration is 0.3%,the afterglow and photostimulable luminescence of the sample are the strongest,which was the initial powder sample with the optimum concentration.The phosphors with the optimal concentration had a weak afterglow and photostimulable luminescence.In order to enhance the luminescence and photostimulable luminescence of the sample,the previous C12A7:0.3%Dy³⁺powder was selected for heat treatment in different atmosphere.First of all,the powder which was calcined in the air by 1000?to remove residual carbon acted as the initial sample,then the initial samples respectively were calcined in air atmosphere under 1300?for 2 h and in nitrogen atmosphere 1300?for 2 h.After heat treatment of different atmosphere where the photostimulable luminescence test was carried out by the afterglow and 808 nm laser excitation,there was strong photostimulable luminescence in the sample under nitrogen atmosphere at 1300?heat treatment after 2 h.Thermoluminescence curves showed thatunder 1300?nitrogen atmosphere heat treatment after 2 h,there was more deep trap whose depth were 0.68 eV and 0.79 eV respectively in the sample.Under nitrogen atmosphere,1300?heat treatment C12A7:0.3%Dy³⁺,compared with the samples without heat treatment,the cage OH^-groups decreased,but the cage O^2–increased,which caused the empty cage of C12A7 increasingthe electron trap was increased.Then,the nitrogen atmosphere under 1300?heat treatment 2 h after the X-ray storage performance of the sample was studied,the sample had a strong photostimulable luminescence and the depth of the trap did not changed through the photostimulable luminescence curve and the thermal release curve.It can be found that,under a moderate amount of X-ray absorbed dose?0.54 Gy?,high quality X-ray imaging can be realized by using an imaging object,which is two thin wires capped with insulating layer,and using an imaging plate,which is a round tablet fabricated by pressed the heattreated C12A7:0.3%Dy³⁺powders.Our results suggest that Dy³⁺doped C12A7 X-ray phosphors have a potential application for the techniques related to digital static X-ray imaging.