Scintillation screen based on gadolinium gallium aluminum garnet scintillation single crystal and preparation method thereof
By fabricating a scintillator based on gadolinium gallium aluminum garnet scintillation single crystal, the problems of poor stability and large-size splicing dead zone of existing scintillator are solved, achieving high sensitivity and high resolution imaging effects, and improving the irradiation stability and service life of the scintillator.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-27
- Publication Date
- 2026-03-24
AI Technical Summary
Existing scintillator materials have poor stability under high-dose irradiation and are prone to discoloration. Furthermore, large-size splicing results in dead zones and high costs, making it difficult to meet the requirements for high-sensitivity and high-resolution detection.
A scintillator screen with a reflective layer and a light-emitting layer was prepared by mixing gadolinium gallium aluminum garnet scintillation single crystal with an inorganic binder. A lightweight material was used as the substrate, and high-temperature sintering and polishing were carried out to ensure uniform particle size distribution and coupling accuracy, thereby improving irradiation stability and imaging quality.
It significantly improves the irradiation stability and imaging quality of the scintillator, reduces afterglow, extends service life, and has a flexible manufacturing process that can adapt to the needs of scintillators of different shapes and sizes.
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Figure CN121721680A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of scintillation screen, in particular to a scintillation screen based on gadolinium gallium aluminum garnet scintillation single crystal and a preparation method thereof. BACKGROUND
[0002] X-ray imaging technology is an important means in the fields of modern nuclear medicine diagnosis, industrial non-destructive testing, security and safety inspection, and scientific research. Among them, the indirect X-ray flat panel detector occupies most of the market due to its simple structure, low cost, and good stability. The core component of the indirect X-ray flat panel detector is the scintillation screen, which converts X-rays into visible light, which enters the photoelectric sensor (CMOS, CCD, a-Si, etc.) to convert the light signal into an electrical signal, and then through data acquisition and processing to finally generate a digital image. Therefore, the X-ray absorption capacity, light emission efficiency, optical uniformity, and stability of the scintillator material directly determine the spatial resolution, sensitivity, and imaging quality of the detector.
[0003] At present, commercial indirect X-ray flat panel detectors generally use needle-shaped thallium-doped cesium iodide (CsI:Tl) and gadolinium oxysulfide (GOS) as scintillation screen materials. Although needle-shaped thallium-doped cesium iodide has high light output and high resolution due to its needle-shaped structure, it has the following disadvantages: first, it has poor radiation resistance and is prone to produce new color centers and discoloration under high-dose, long-term irradiation, which reduces the light output and affects the imaging quality; second, it has high afterglow value and is prone to image smearing in high-speed imaging; third, thallium-doped cesium iodide has deliquescence and must be sealed and packaged, which increases the process complexity, manufacturing cost, and system volume. Gadolinium oxysulfide has high detection efficiency and is easy to prepare large size, but it belongs to polycrystalline structure, which will cause serious light scattering and limit the improvement of spatial resolution, and its light emission efficiency is relatively low, which is difficult to meet the demand of high sensitivity and high resolution detection.
[0004] In recent years, various new scintillator materials applied to indirect X-ray flat panel detectors have emerged, and gadolinium gallium aluminum garnet scintillation crystal (Ce:GAGG) as a new type of inorganic scintillator material shows great potential, and has the advantages of high density, high light yield, fast decay time, low afterglow, no deliquescence, radiation resistance and stable physical and chemical properties. However, the application of gadolinium gallium aluminum garnet scintillation crystal to large-size X-ray flat panel detectors faces severe challenges: the crystal growth technology is difficult to prepare large-size, high-uniformity, low-defect high-quality single crystal, and at the same time, multiple single crystal sheets need to be spliced together in the application, which has the problems of large "dead zone", high cost and low yield; the large-size scintillation screen prepared by mixing scintillation crystal particles and organic binder has the problems of easy denaturation, discoloration and the like in long-term radiation environment, resulting in the problems of decreased light transmission efficiency, poor stability and shortened service life; the gadolinium gallium aluminum garnet scintillation ceramic has the same problems as the existing gadolinium sulfate. SUMMARY
[0005] The application discloses a scintillation screen based on gadolinium gallium aluminum garnet scintillation single crystal and a preparation method thereof, so as to solve the problems of existing schemes in terms of radiation stability, environmental adaptability and long-term reliability.
[0006] To achieve the above technical effects, in a first aspect, a scintillation screen based on gadolinium gallium aluminum garnet scintillation single crystal is provided, characterized in that the scintillation screen comprises, from bottom to top, a substrate, a light-reflecting layer, a gadolinium gallium aluminum garnet scintillator powder screen and a light-emitting layer. An inner groove is arranged on the upper surface of the light-reflecting layer, and the gadolinium gallium aluminum garnet scintillator powder screen is arranged in the inner groove. The substrate is made of a lightweight material that is not sensitive to X-rays. The light-reflecting layer is made of a reflective material having high reflectivity in the emission spectrum band of the Ce:GAGG scintillation crystal. The gadolinium gallium aluminum garnet scintillator powder screen is prepared by mixing and sintering gadolinium gallium aluminum garnet scintillation single crystal particles and inorganic binder in a certain proportion and then polishing. The light-emitting layer is made of a material that improves the light emission efficiency of the Ce:GAGG scintillation crystal.
[0007] Further, the substrate is specifically made of any one of the following: K9 glass, organic glass, carbon fiber plate and aluminum plate.
[0008] Further, the light-reflecting layer is specifically made of any one of the following: Barium sulfate material, titanium dioxide material, ESR film, aluminum plating material, gold plating material and silver plating material.
[0009] Further, the gadolinium gallium garnet scintillator powder screen adopts a ratio of gadolinium gallium garnet scintillator single crystal particles to inorganic binder of 1:0.05 to 1:0.95.
[0010] Further, the light-emitting layer specifically adopts any one of the following: Dielectric film, antireflection film, unidirectional light-emitting film.
[0011] In a second aspect, a preparation method of a scintillation screen based on gadolinium gallium garnet scintillator single crystal is provided, and the specific method is as follows: The gadolinium gallium garnet scintillator crystal is ball milled into single crystal particles with a particle size meeting a preset value, and the particle size distribution range is controlled; The single crystal particles are mixed with an inorganic binder with a melting point lower than that of the scintillator crystal, and a sintering aid and a stress buffer are added and uniformly mixed; The mixed material is placed in a mold for compression molding; The molded powder screen blank is placed in a high-temperature furnace for sintering, and after sintering is completed, the temperature is lowered to room temperature at a preset rate; The sintered powder screen is ground and polished; The light-reflecting layer and the light-emitting layer are surface treated; Finally, the powder screen is coupled with the substrate to achieve a preset coupling accuracy.
[0012] Further, the single crystal particle size is less than 1000 μm, and the particle size distribution range is controlled to be less than ±20%; The pressure range for compression molding in the mold is 5-200 MPa; The sintering condition is to heat at 10-100 ℃ / h to 500-800 ℃ for 1-10 hours, and the preset rate is 10-50 ℃ / h; After the grinding and polishing processing, the surface roughness Ra of the powder screen is ≤1 μm, and the flatness is ≤0.03 mm; The preset coupling accuracy is ≤10 μm.
[0013] Further, the inorganic binder is SiO2, and the ratio is 1:0.05-1:0.95; the sintering aid is B2O3, and the ratio is less than 1%; the stress buffer is Al2O3, and the ratio is less than 1%, and the particle size of the inorganic binder, the sintering aid, and the stress buffer needs to be less than 50% of the particle size of the gadolinium gallium garnet scintillator crystal.
[0014] Further, the mold is made of a material that does not chemically react with the scintillator crystal and other materials, including but not limited to metal, hard alloy, or engineering plastic; The compression molding adopts unidirectional compression, bidirectional compression, or isostatic pressing.
[0015] Further, the sintering in the high-temperature furnace is carried out in an environment of air, inert gas, or vacuum. Polishing methods include, but are not limited to, mechanical and chemical methods; Coupling is performed using a clamp or coupling device, with the coupling method being air, silicone oil, or optical adhesive.
[0016] Due to the adoption of the above technical solutions, this application has the following beneficial effects: This invention solves the problems of existing needle-shaped cesium iodide scintillator screens being intolerant to radiation, prone to deliquescence, and having poor afterglow; gadolinium oxysulfate ceramic scintillator screens having poor resolution and low luminous efficiency; and Ce:GAGG single-crystal spliced scintillator screens having dead zones. It significantly improves the radiation stability, environmental adaptability, and service life of scintillator screens. At the same time, the manufacturing process is flexible and can produce high-performance scintillator screens of different shapes and sizes.
[0017] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description
[0018] The accompanying drawings of this invention are described below.
[0019] Figure 1 This is a schematic diagram of the structure of a flickering screen.
[0020] Figure 2 This is a schematic diagram of the process for fabricating a flickering screen.
[0021] In the figure: 1. Substrate; 2. Reflective layer; 3. Gadolinium gallium aluminum garnet scintillator powder screen; 4. Light-emitting layer. Detailed Implementation
[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments.
[0023] Example 1: A scintillator screen based on gadolinium gallium aluminum garnet scintillation single crystal, such as Figure 1 As shown, the scintillating screen includes a substrate 1, a reflective layer 2, a gadolinium gallium aluminum garnet scintillator powder screen 3, and a light-emitting layer 4.
[0024] The substrate is made of lightweight materials that are not sensitive to X-rays, including K9 glass, plexiglass, carbon fiber board, aluminum plate and other materials.
[0025] The reflective layer uses reflective materials with high reflectivity to the scintillation emission spectrum of Ce:GAGG scintillation crystals, including barium sulfate, titanium dioxide, ESR film, aluminum plating, gold plating, silver plating, and other materials.
[0026] The gadolinium gallium aluminum garnet scintillator powder screen is prepared by mixing and sintering gadolinium gallium aluminum garnet scintillator single crystal particles and inorganic binder in a proportion of 1:0.05-1:0.95 and then polishing.
[0027] The light-emitting layer is made of a material for improving the scintillation light emission efficiency of the Ce:GAGG scintillation crystal, including a dielectric film, an anti-reflection film, a unidirectional light-emitting film, etc.
[0028] Embodiment 2 A preparation method of a scintillation screen based on gadolinium gallium aluminum garnet scintillation single crystal, as shown in Figure 2 The specific steps are as follows: The gadolinium gallium aluminum garnet scintillation crystal is crushed into single crystal particles with a particle size of less than 1000 μm by mechanical stirring, ball milling and other methods, and the particle size distribution range is controlled to be less than ±20% using a screen.
[0029] The single crystal particles are mixed with an inorganic binder with a melting point lower than that of the scintillation crystal, and a small amount of sintering aid and stress buffer are added and uniformly mixed. The inorganic binder is SiO2, and the proportion is 1:0.05-1:0.95. The sintering aid is B2O3, and the proportion is less than 1%. The stress buffer is Al2O3, and the proportion is less than 1%. The particle sizes of the inorganic binder, the sintering aid and the stress buffer need to be less than 50% of the particle size of the gadolinium gallium aluminum garnet scintillation crystal.
[0030] The mixed material is placed in a mold and pressed into shape under a pressure of 5-200 MPa. The mold is made of a material that does not chemically react with the scintillation crystal and other materials, including but not limited to metal, hard alloy or engineering plastic. The pressing can be unidirectional pressing, bidirectional pressing or isostatic pressing.
[0031] The shaped powder screen blank is placed in a high-temperature furnace and heated at a rate of 10-100 ℃ / h to 500-800 ℃ for 1-10 hours for sintering. After sintering, the temperature is lowered to room temperature at a rate of 10-50 ℃ / h. The sintering in the high-temperature furnace can be carried out in an air, inert gas or vacuum environment.
[0032] The sintered powder screen is polished to make the surface roughness Ra≤1 μm and the flatness ≤0.03 mm. The polishing method includes but is not limited to mechanical and chemical methods.
[0033] The surface is treated with a light-reflecting layer and a light-emitting layer as needed. The light-reflecting layer includes but is not limited to TiO2, BaSO4 and other reflective materials, ESR film, gold, silver, aluminum and other mirror surface reflective materials. The light-emitting layer includes but is not limited to anti-reflection film, unidirectional light-emitting film, spin-on photonic crystal, etc.
[0034] Finally, the powder screen is coupled with the substrate. The coupling can be carried out by a clamp or a coupling device, and the coupling accuracy is ≤10 μm. The coupling method can be air or optical adhesive.
[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.
Claims
1. A scintillator screen based on gadolinium gallium aluminum garnet scintillation single crystal, characterized in that, The scintillating screen comprises, from bottom to top, a substrate, a reflective layer, a gadolinium gallium aluminum garnet scintillator powder screen, and a light-emitting layer; The upper surface of the reflective layer is provided with an inner groove, and the gadolinium gallium aluminum garnet scintillator powder screen is disposed in the inner groove; The substrate is made of a lightweight material that is insensitive to X-rays; The reflective layer is made of a reflective material with high reflectivity to the emission spectrum of Ce:GAGG scintillation crystal scintillation light. The gadolinium gallium aluminum garnet scintillator powder screen is prepared by mixing gadolinium gallium aluminum garnet scintillator single crystal particles with an inorganic binder in a certain proportion, sintering, and then polishing. The light-emitting layer uses a material that enhances the scintillation light emission efficiency of the Ce:GAGG scintillation crystal.
2. The scintillator screen based on gadolinium gallium aluminum garnet scintillation single crystal as described in claim 1, characterized in that, The substrate specifically adopts any one of the following: K9 glass, acrylic glass, carbon fiber sheet, aluminum sheet.
3. The scintillator screen based on gadolinium gallium aluminum garnet scintillation single crystal as described in claim 1, characterized in that, The reflective layer specifically adopts any one of the following: Barium sulfate materials, titanium dioxide materials, ESR membranes, aluminum-plated materials, gold-plated materials, and silver-plated materials.
4. The scintillator screen based on gadolinium gallium aluminum garnet scintillation single crystal as described in claim 1, characterized in that, The gadolinium gallium aluminum garnet scintillator powder screen uses gadolinium gallium aluminum garnet scintillator single crystal particles and inorganic binder in a ratio of 1:0.05 to 1:0.
95.
5. The scintillator screen based on gadolinium gallium aluminum garnet scintillation single crystal as described in claim 1, characterized in that, The light-emitting layer specifically adopts any one of the following: Dielectric film, antireflective film, one-way light emission film.
6. A method for fabricating a scintillation screen based on gadolinium gallium aluminum garnet scintillation single crystal, characterized in that, The specific method is as follows: Gadolinium gallium aluminum garnet scintillation crystals are ball-milled into single-crystal particles with a particle size that meets a preset value, thereby controlling the particle size distribution range; The single crystal particles are mixed with an inorganic binder with a melting point lower than that of the scintillation crystal, and sintering aids and stress buffers are added and mixed evenly. The mixture is placed in a mold and pressed into shape; The shaped powder screen blank is placed in a high-temperature furnace for sintering, and after sintering, it is cooled to room temperature at a preset rate. The sintered powder screen is then ground and polished. Surface treatment is performed on the reflective layer and the light-emitting layer; Finally, the powder screen is coupled to the substrate to achieve the preset coupling accuracy.
7. The method for fabricating a scintillation screen based on gadolinium gallium aluminum garnet scintillation single crystal as described in claim 6, characterized in that, The single crystal particles have a diameter of less than 1000 μm, and the particle size distribution is controlled to be less than ±20%. The pressure range during molding is 5-200MPa; The sintering conditions are to raise the temperature to 500-800℃ at a rate of 10-100℃ / h and hold for 1-10 hours, with the preset rate reduced to 10-50℃ / h. After grinding and polishing, the surface roughness Ra of the powder screen is ≤1μm, and the flatness is ≤0.03mm; Preset coupling accuracy ≤10μm.
8. The method for fabricating a scintillation screen based on gadolinium gallium aluminum garnet scintillation single crystal as described in claim 6, characterized in that, The inorganic binder is SiO2, with a ratio of 1:0.05-1:0.95; the sintering aid is B2O3, with a ratio of less than 1%; the stress buffer is Al2O3, with a ratio of less than 1%. The particle size of the inorganic binder, sintering aid, and stress buffer must be less than 50% of the size of the gadolinium gallium aluminum garnet scintillation crystal particles.
9. The method for fabricating a scintillation screen based on gadolinium gallium aluminum garnet scintillation single crystal as described in claim 6, characterized in that, The mold is made of a material that does not chemically react with the scintillation crystal and other materials, including but not limited to metals, hard alloys, or engineering plastics; Compression molding can be performed using unidirectional compression, bidirectional compression, or isostatic pressing.
10. The method for fabricating a scintillation screen based on a gadolinium gallium aluminum garnet scintillation single crystal as described in claim 6, characterized in that, Sintering in a high-temperature furnace is carried out in an environment such as air, inert gas, or vacuum. Polishing methods include, but are not limited to, mechanical and chemical methods; Coupling is performed using a clamp or coupling device, with the coupling method being air, silicone oil, or optical adhesive.