Preparation method and application of crystal material for X-ray imaging

Abstract

The invention belongs to the technical field of radiation detection materials, and particularly relates to a preparation method and application of a crystal material for X-ray imaging, and the preparation method comprises the following steps: dissolving rubidium bromide and manganese bromide in hydrobromic acid, and cooling after the reaction is completed; collecting a product, and fully washing; and carrying out heat treatment on the obtained product to obtain the crystal material. The crystal material disclosed by the invention has relatively good spectral performance and decay time, the preparation method is simple, and the material is environment-friendly and low in toxicity.

Description

Technical Field

[0001] This invention belongs to the field of radiation detection materials technology, specifically relating to a method for preparing and applying a crystal material for X-ray imaging. Background Technology

[0002] With technological advancements, perovskite scintillation materials have found widespread application in various fields, including medical imaging, non-destructive testing, national defense, and anti-counterfeiting coatings, due to their excellent scintillation properties such as high light yield. However, the inherent toxicity of traditional lead-based perovskite scintillation materials has become a significant issue due to increasing environmental awareness. To mitigate the environmental impact of scintillation materials, researchers have been exploring new, green perovskite scintillation materials.

[0003] Against this backdrop, manganese-based metal halide perovskites exhibit significant advantages. Manganese is an abundant, environmentally friendly, and inexpensive element that has attracted widespread attention across various fields of materials science. A key characteristic of divalent manganese ions is their unique luminescence mechanism, characterized by… 6 A1→ 4 The single transition of T1(G), resulting in a single emission, is less susceptible to the influence of the ligand field and avoids competition among multiple emission mechanisms. This enables highly efficient emission, providing an important foundation for the development of high-performance scintillation materials. Therefore, all-inorganic manganese-based halide perovskites possess enormous radiation detection potential due to their excellent stability, simple preparation methods, and heavy element composition, making them suitable for meeting the high spatial resolution requirements of X-ray imaging. Summary of the Invention

[0004] To address the problems of high toxicity, poor imaging performance, and insufficient stability of traditional lead-based perovskite scintillation materials in existing technologies, this invention mainly provides a Rb₂MnBr₄(H₂O)₂ crystal material, a method for preparing a flexible X-ray imaging composite film using this crystal, and its applications. The technical solution is as follows: A method for preparing a crystal material for X-ray imaging includes the following steps: dissolving rubidium bromide and manganese bromide in hydrobromic acid, cooling after the reaction is complete; collecting the product and washing it thoroughly; and heat-treating the obtained product to obtain the crystal material.

[0005] Furthermore, the molar ratio of rubidium bromide to manganese bromide is 2-3:1; and the mass concentration of hydrobromic acid is 30-40%.

[0006] Furthermore, rubidium bromide and manganese bromide are dissolved in hydrobromic acid to prepare rubidium bromide solution and manganese bromide solution, respectively; the volume ratio of rubidium bromide solution to manganese bromide solution is 4~8:1.

[0007] Furthermore, the reaction temperature is 50~70℃; the reaction is carried out under ultrasound; and the reaction time is 10~20min.

[0008] Furthermore, the cooling temperature is -5 to 5°C; the cooling time is 40 to 2 hours.

[0009] Furthermore, the heat treatment temperature is 105~140℃; the heat treatment time is 6~12h.

[0010] A crystal material for X-ray imaging prepared by the above-described method.

[0011] A method for preparing a flexible X-ray imaging composite film includes the following steps: grinding the X-ray imaging crystal material as described in claim 7, mixing it evenly with a polymer, and then vacuum drying to obtain a mixture; forming the mixture into a thin film and drying it to obtain the final product.

[0012] Furthermore, the polymer is dimethylsiloxane; the mass ratio of the crystalline material to the polymer is 1:1.2~2.

[0013] An application of the aforementioned crystal material for X-ray imaging in radiation detection.

[0014] By adopting the above scheme, the method of the present invention has the following advantages: 1. The crystal preparation method of the present invention includes steps such as accurately weighing raw materials, dissolving in acid, uniform mixing, and cooling crystallization. This preparation method can ensure the integrity of the perovskite material's crystal lattice and the uniformity of its particles, thereby generating a stable fluorescence signal that is correlated with the intensity of incident X-rays under X-ray irradiation, thus enabling the reading of X-ray information.

[0015] 2. This invention utilizes heat treatment to enhance the luminescence intensity of the crystal at room temperature, thereby obtaining better X-ray imaging data. Simultaneously, the uniform Rb2MnBr4(H2O)2 flexible imaging composite film exhibits less light scattering and better flexibility, which is beneficial for achieving high spatial resolution X-ray curved surface imaging.

[0016] 3. By optimizing factors such as the preparation process of Rb2MnBr4(H2O)2, this invention can effectively control the luminescence properties of Rb2MnBr4(H2O)2, giving it higher light yield, higher spatial resolution and better long-term stability, which can meet the needs of X-ray imaging applications. Attached Figure Description

[0017] Figure 1 The XRD full spectrum fitting pattern of Rb2MnBr4(H2O)2 crystal material; Figure 2Image showing the results of scanning electron microscopy and EDS surface scanning of Rb2MnBr4(H2O)2 crystal material; Figure 3 This is a comparison graph of the relative fluorescence intensity of Examples 1 and 2 and Comparative Examples 1 and 2; Figure 4 The X-ray absorption coefficient of Rb2MnBr4(H2O)2 crystal material; Figure 5 A comparison chart of the light yield of Rb2MnBr4(H2O)2 crystal material and commercial BGO; Figure 6 The fluorescence decay time of Rb2MnBr4(H2O)2 crystal material at 655 nm; Figure 7 The images show the flexible X-ray imaging composite film under natural light and ultraviolet excitation. Figure 8 A schematic diagram illustrating the flexible properties of a flexible X-ray imaging composite film; Figure 9 A comparison of the stability of the flexible X-ray imaging composite film and the Rb2MnBr4(H2O)2 crystal material; Figure 10 Schematic diagram of an X-ray imaging and imaging device; Figure 11 This is a schematic diagram of the X-ray imaging results; Figure 12 This is a schematic diagram showing the imaging results of the flexible X-ray imaging composite film under different test currents and voltages. Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1: (1) Rubidium bromide RbBr and manganese bromide MnBr2 were weighed in a molar ratio of 2:1 and dissolved in 35% hydrobromic acid to prepare rubidium bromide solution and manganese bromide solution with a volume ratio of 4:1. (2) Mix rubidium bromide solution and manganese bromide solution, and then sonicate at 60°C for 15 minutes; cool the system at 5°C, and after 1 hour, a uniform solid precipitates in the system. Wash the solid three times with isopropanol and dry it to obtain crystals. (3) The crystal was heat-treated at 120℃ for 8h to obtain Rb2MnBr4(H2O)2 crystal material; Combination Figure 1The XRD full spectrum fitting results of Rb2MnBr4(H2O)2 crystal material and Figure 2 The scanning electron microscope images and EDS surface scan results show that the obtained sample is Rb2MnBr4(H2O)2 crystal. (4) Grind the Rb2MnBr4(H2O)2 crystal material for 2 hours, mix it with polydimethylsiloxane at a mass ratio of 2:3, and then vacuum dry it. Then, use screen printing to make a thin film and place it in an oven to dry at 60°C for 2 hours to obtain a flexible X-ray imaging composite film.

[0020] Example 2: The difference from Example 1 is as follows: (3) The crystal was heat-treated at 140℃ for 8h to obtain the final Rb2MnBr4(H2O)2 crystal.

[0021] Comparative Example 1: The difference from Example 1 is that: (3) The crystal was heat-treated at 100℃ for 8h to obtain the final Rb2MnBr4(H2O)2 crystal.

[0022] Comparative Example 2: The difference from Example 1 is that: (3) The crystal was heat-treated at 80℃ for 8h to obtain the final Rb2MnBr4(H2O)2 crystal.

[0023] Comparative Example 3: The difference from Example 1 is that: (1) Rubidium bromide RbBr and manganese bromide MnBr2 were weighed in a molar ratio of 2:1 and dissolved in 35% hydrobromic acid to prepare rubidium bromide solution and manganese bromide solution with a volume ratio of 10:1.

[0024] Comparative Example 3 ultimately failed to yield a product.

[0025] Example Sample Testing: A comparative experiment was conducted on the relative red fluorescence intensity of Examples 1 and 2 and Comparative Examples 1 and 2. The results are as follows: Figure 3 As shown in the figure, after heat treatment using the method of the present invention, Examples 1 and 2 exhibited enhanced red luminescence of the Rb2MnBr4(H2O)2 crystal at room temperature, resulting in higher X-ray imaging resolution. In contrast, Comparative Examples 1 and 2, with lower temperatures, showed significantly reduced intensity. Comparative Example 2, with a heat treatment temperature of only 80°C, was unsuitable for X-ray imaging. Furthermore, the intensity of Example 2, with its higher treatment temperature, was lower than that of Example 1, indicating that excessively high treatment temperatures can also have negative effects, and optimal performance can only be achieved within a suitable temperature range.

[0026] Figure 4 and Figure 5The prepared Rb₂MnBr₄(H₂O)₂ crystal was tested in X-ray detection. Compared with common scintillation crystals BGO (bismuth germanate) and CsI:Tl (cesium thallium doped iodide), the Rb₂MnBr₄(H₂O)₂ crystal showed comparable X-ray absorption capacity, and even outperformed these two materials in certain photon energy ranges (e.g., 1–3 keV and 13–32 keV). This demonstrates the potential of Rb₂MnBr₄(H₂O)₂ crystal as a scintillation material. To measure the ability of the Rb₂MnBr₄(H₂O)₂ crystal to convert X-ray photons into visible light photons, the light yield of the Rb₂MnBr₄(H₂O)₂ crystal was further tested using comparative methods, such as... Figure 5 As shown, commercial BGO is used as a reference standard. The light yield of BGO is 8600 photons / MeV. Through comparative analysis of the RL area, the light yield of Rb2MnBr4(H2O)2 crystal can be calculated to be 8329 photons / MeV. It can be seen that Rb2MnBr4(H2O)2 crystal has a light yield comparable to commonly used scintillation crystals on the market, and can be used as a green scintillation material to replace traditional scintillation materials.

[0027] like Figure 6 As shown, the PL peak intensity I(t) at room temperature can be expanded using two exponential decay components, where τ1 and τ2 represent the decay lifetimes of different emission components, and parameters A1 and A2 are weighting factors. The fitting formula is as follows: .

[0028] The fitting revealed that the decay time of the emission peak centered at 655 nm has two components: 85 μs and 342 μs, with an average decay time of 310 μs. For light emission at 655 nm, the decay time (~85 μs) is likely related to the nonradiative transitions and exciton trapping of water, while the decay time (~342 μs) is likely related to the intrinsic luminescence of divalent manganese ions.

[0029] Figure 7 and Figure 8 This is a schematic diagram of a flexible X-ray imaging composite film. Under ambient light, the composite film appears uniformly white, while under high-energy radiation excitation, it exhibits a bright red color. The prepared composite film can withstand strong bending, twisting, and compression, demonstrating its great application potential in curved surface X-ray imaging.

[0030] Furthermore, to characterize the stability of the flexible X-ray imaging composite film prepared by Rb2MnBr4(H2O)2, it was placed for an extended period of time, and its fluorescence intensity was tested at regular intervals. Figure 9As shown, "RMBH@PDMS" is a flexible film made by combining Rb2MnBr4(H2O)2 and PDMS. "RMBH powder" represents Rb2MnBr4(H2O)2 powder exposed to air. It can be seen that the stability is greatly improved after Rb2MnBr4(H2O)2 is made into a flexible film.

[0031] To characterize the spatial resolution of an X-ray imaging system, the spatial resolution of a Rb₂MnBr₄(H₂O)₂ flexible X-ray imaging composite film was tested using a direct method. The direct testing method involves X-ray scanning imaging of standard components with periodic structures of varying spacing, followed by analysis of the periodic images. The maximum number of distinguishable fringes or circular apertures determines the spatial resolution. This method allows for direct measurement of the system's spatial resolution from X-ray images. We used the Rb₂MnBr₄(H₂O)₂ flexible X-ray imaging composite film as the X-ray imaging medium to image a standard X-ray resolution plate, visually demonstrating the X-ray imaging capability of the Rb₂MnBr₄(H₂O)₂ flexible X-ray imaging composite film. Figure 10 This is a schematic diagram of an X-ray imaging measurement device. Figure 11 The images show the physical specimen of the standard resolution plate used for imaging and the imaging results. The target material used in the X-ray source was a chromium target, with an operating voltage and current of 120 kV and 750 μA, respectively. A flexible X-ray imaging composite film of Rb2MnBr4(H2O)2 was used as the X-ray imaging medium to image the standard resolution plate. The results show that the X-ray image of the 14.3 line pairs / mm resolution portion of the plate is clearly visible, indicating that the resolution of the Rb2MnBr4(H2O)2 flexible X-ray imaging composite film is at least 14.3 line pairs / mm.

[0032] To verify the effectiveness of the Rb2MnBr4(H2O)2 flexible X-ray imaging composite film in physical X-ray detection imaging, the Rb2MnBr4(H2O)2 flexible X-ray imaging composite film was subsequently used to image X-rays at different doses, and the imaging effect under different X-ray doses was evaluated using standardized imaging parameters, with the exposure time fixed at 3 seconds. Figure 12 In the first row, the tube voltage varied from 80 kV to 140 kV, while the tube current remained at 500 μA; in the second row, the tube current varied from 25 μA to 1250 μA, while the tube voltage remained at 120 kV. Based on the imaging results, it is clear that selecting a voltage of 120 kV and a current of 750 μA or 1000 μA is the optimal choice. The optimal parameters obtained in this experiment can provide guidance for the practical application of this material.

[0033] This invention discovers that Rb₂MnBr₄(H₂O)₂ crystals can produce red visible light under X-ray irradiation, a property that makes them suitable for X-ray imaging. After high-temperature heat treatment, the emission wavelength of the material changes from 655 nm to 521 nm, and different emission colors are obtained, demonstrating its potential for temperature sensing applications. Combining Rb₂MnBr₄(H₂O)₂ with PDMS can prepare a flexible composite film suitable for X-ray imaging, achieving a high spatial resolution of 14.3 line pairs / mm and almost tripling the stability of Rb₂MnBr₄(H₂O)₂ powder: the time for the film fluorescence intensity to drop to zero is extended from 16 days to 45 days, and the light intensity decrease rate is reduced from 6.82% to 1.38%. Simultaneously, the imaging performance under different test tube currents and voltages was characterized and optimized, yielding instructive parameter conclusions.

[0034] For those skilled in the art, various other corresponding changes and modifications can be made based on the technical solutions and concepts described above, and all such changes and modifications should fall within the protection scope of the claims of this invention.

Claims

1. A method for preparing a crystal material for X-ray imaging, characterized in that, Includes the following steps: Rubidium bromide and manganese bromide were dissolved in hydrobromic acid, and the mixture was cooled after the reaction was complete. Collect the product and wash it thoroughly; heat-treat the obtained product to obtain crystalline material.

2. The method for preparing crystal materials for X-ray imaging according to claim 1, characterized in that, The molar ratio of rubidium bromide to manganese bromide is 2-3:1; the mass concentration of hydrobromic acid is 30-40%.

3. The method for preparing crystal materials for X-ray imaging according to claim 1, characterized in that, Rubidium bromide and manganese bromide were dissolved in hydrobromic acid to prepare rubidium bromide solution and manganese bromide solution, respectively; the volume ratio of rubidium bromide solution to manganese bromide solution was 4~8:

1.

4. The method for preparing crystal materials for X-ray imaging according to claim 1, characterized in that, The reaction temperature is 50~70℃; the reaction is carried out under ultrasound; the reaction time is 10~20min.

5. The method for preparing crystal materials for X-ray imaging according to claim 1, characterized in that, The cooling temperature is -5~5℃; the cooling time is 40~2h.

6. The method for preparing crystal materials for X-ray imaging according to claim 1, characterized in that, The heat treatment temperature is 105~140℃; the heat treatment time is 6~12h.

7. A crystal material for X-ray imaging prepared by the preparation method according to any one of claims 1 to 6.

8. A method for preparing a flexible X-ray imaging composite film, characterized in that, The process includes the following steps: grinding the X-ray imaging crystal material as described in claim 7, mixing it evenly with a polymer, and then vacuum drying to obtain a mixture; forming the mixture into a thin film and drying it to obtain the final product.

9. The method for preparing a crystal material for X-ray imaging according to claim 8, characterized in that, The polymer is dimethylsiloxane; the mass ratio of the crystal material to the polymer is 1:1.2~2.

10. The application of the crystal material for X-ray imaging as described in claim 7 in high-energy particle detection.

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