Regulation and control method for radiation photoluminescence characteristics of silver-doped phosphate glass

Abstract

The invention provides a method for regulating and controlling the radiation photoluminescence characteristic of silver-doped phosphate glass, which comprises the following specific steps: preparing Ag-PG through a high-temperature melting annealing process, and regulating the AgCl doping concentration as required to control the content of Ag0 and Ag < 2 + > so as to regulate and control the strength and decay time of RPL. The polished Ag-PG is exposed to an X-ray source, irradiation conditions are controlled to record X-ray information, and heat treatment is performed to accelerate formation of an internal luminescence center. Ag-PG is excited by ultraviolet light to generate an RPL signal, and stored X-ray information is read. The luminescence property of Ag-PG is evaluated through a PL spectrum, and the spatial resolution of Ag-PG is evaluated through an X-ray imaging test. And the irradiated Ag-PG is subjected to annealing treatment, the initial state of the Ag-PG is recovered, and recycling is achieved. Through the optimization measures, the RPL performance and the X-ray imaging performance of the Ag-PG are remarkably improved. The method not only realizes submicron spatial resolution, but also has great practical application value in the field of X-ray imaging.

Description

Technical Field

[0001] The invention belongs to the technical field of X-ray imaging, and in particular relates to a method for regulating radiation photoluminescence characteristics of silver-doped phosphate glass. Background Art

[0002] With the advancement of science and technology, X-ray imaging technology has been widely used in many fields such as medicine, materials science, biology, etc. However, traditional X-ray imaging technology faces challenges such as low resolution, slow imaging speed and large equipment size. In order to overcome these limitations and improve imaging quality and efficiency, researchers have been exploring new imaging materials and technologies.

[0003] In this context, silver-doped phosphate glass (Ag-PG) stands out as an innovative X-ray imaging material. Ag-PG can effectively record X-ray radiation information and produce luminescence through ultraviolet excitation, thereby realizing offline reading. This feature not only brings new possibilities to the field of X-ray detection and imaging, but also its unique properties are worth further introduction. The radiative photoluminescence (RPL) property of Ag-PG, that is, its ability to emit light after X-ray irradiation and read information under ultraviolet excitation, provides it with the following advantages in the field of imaging:

[0004] High resolution: By finely controlling the RPL properties of Ag-PG, submicron or even nanometer spatial resolution can be achieved without sacrificing imaging quality.

[0005] High sensitivity: Ag-PG has a strong response to X-rays and can improve the sensitivity of imaging.

[0006] Offline reading: The RPL feature allows offline reading after irradiation, providing greater flexibility and convenience.

[0007] These characteristics make Ag-PG have great application potential in micro- and nano-scale structure observation.

[0008] Traditional X-ray imaging technology mainly relies on the absorption and scattering of X-rays in matter to generate images. However, the resolution and sensitivity of this technology are limited by the properties of the material itself and the detection technology. In contrast, by precisely controlling the RPL properties of Ag-PG, we can break through these limitations while maintaining imaging quality and achieve a higher level of spatial resolution.

[0009] In response to the above challenges, the present invention proposes a method for regulating the radiation photoluminescence properties of silver-doped phosphate glass, aiming to solve the problems of traditional imaging technology and promote the further development of X-ray imaging technology. Summary of the invention

[0010] The present invention solves the technical problems of low imaging resolution, slow imaging speed and large imaging device size in the above-mentioned prior art X-ray imaging technology.

[0011] To achieve the above object, the present invention provides the following technical solutions:

[0012] A method for regulating the radiation photoluminescence properties of silver-doped phosphate glass comprises the following steps:

[0013] S1. Material preparation and doping: Select appropriate proportion of sodium hexametaphosphate Na6O 18 P6, aluminum dihydrogen phosphate Al(H2PO4)3 and silver chloride AgCl are fully mixed, and then the mixture is placed in a high-temperature reactor to melt L and cool and anneal to obtain Ag-PG. The prepared Ag-PG is cut into the required size and double-mirror polished to make its surface smooth to improve its optical transmittance, thereby optimizing the spatial resolution of X-ray imaging. The concentration of doped AgCl is controlled to control the Ag 0 and Ag 2+ The content of , thus affecting its RPL intensity and decay time;

[0014] S2. X-ray irradiation: Expose the polished Ag-PG to an X-ray source to record X-ray information. The irradiation dose of the sample is regulated by controlling the current and voltage of the X-ray source to facilitate subsequent regulation and imaging;

[0015] S3, heat treatment optimization: heat treatment of the prepared Ag-PG to enhance its RPL strength;

[0016] S4, RPL excitation: by irradiating Ag-PG with ultraviolet light, its RPL is stimulated to emit light, thereby reading the stored X-ray information;

[0017] S5. Material performance test: PL spectrum test is performed on the Ag-PG after different regulation steps to evaluate its luminescence performance. The test parameters include luminescence curve and decay time;

[0018] S6. X-ray imaging test: X-ray imaging test is performed on the Ag-PG after different regulation steps to evaluate its imaging performance. The test parameters include spatial resolution. The X-ray imaging test uses direct and indirect methods to test and verify the spatial resolution of Ag-PG.

[0019] S7. Performance optimization and repeated experiments: Based on the test results, the RPL performance and X-ray imaging performance of Ag-PG are optimized, including adjusting the doping concentration, heat treatment temperature and irradiation conditions; and the stability and repeatability of the control method are verified through repeated experiments;

[0020] S8. Reuse of Ag-PG: After X-ray irradiation and heat treatment, the Ag-PG is annealed and heated at 400°C for 2 hours to eliminate the RPL color center and other irradiation damage and restore its initial state for reuse. The annealed Ag-PG is re-irradiated with X-rays to record new X-ray information to achieve the recycling of Ag-PG.

[0021] Preferably, the preparation of Ag-PG in step 1 comprises the following steps:

[0022] S1.1. First, sodium hexametaphosphate Na6O 18 P6, aluminum dihydrogen phosphate Al(H2PO4)3 and silver chloride AgCl were uniformly mixed in a crucible according to Na:Al:Ag=70:30:1;

[0023] S1.2, then put the crucible containing the mixed materials into a muffle furnace for preheating and degassing, the muffle furnace is heated from 25°C to 600°C at 5°C / min, and kept at 600°C for 1 hour, then transferred to a high-temperature reaction furnace for melting and heated to 1300°C, and kept at this temperature for 2 hours, so that the raw materials are completely melted and evenly mixed;

[0024] S1.3, then, the molten Ag-PG was cast into a graphite mold preheated at 420°C, and after cooling and solidification, it was annealed in a muffle furnace at 420°C for 30 hours;

[0025] S1.4. Finally, the Ag-PG cooled to 25°C is taken out, cut into Ag-PG sheets of specified size, and then double-mirror polished into samples to obtain Ag-PG circular sheets or Ag-PG square sheets.

[0026] Preferably, in step S3, Ag-PG is heat treated at 100° C. for 1 hour.

[0027] Preferably, after X-ray irradiation in step S2, Ag has been formed inside the Ag-PG material. 0 and Ag 2+ There are two stable luminescence centers. Ultraviolet light excites the electrons in the luminescence center to the conduction band, and they emit light in the process of transitioning back to the luminescence center.

[0028] Preferably, ultraviolet excitation is used in step S4 to read the stored X-ray information, and the RPL spectrum and fluorescence decay curve are analyzed to evaluate the radiation photoluminescence characteristics of Ag-PG and perform necessary optimization.

[0029] Preferably, the luminescence peak intensity and decay time in the RPL spectrum in step S1 are described by the following formula:

[0030]

[0031] Among them, I(t) represents the RPL intensity at time t; τ1, τ2, τ3 represent the decay lifetimes of different luminous components; and parameters A1, A2, A3 are weighting factors.

[0032] Preferably, in step S6, the direct method steps are as follows:

[0033] Prepare standard test parts: Prepare periodic standard parts with known spacing and structure, such as square hole gold grids, for X-ray imaging tests;

[0034] X-ray scanning imaging: Use an X-ray source to scan and image the square hole gold grid, ensuring that the operating voltage and current of the X-ray source are set within the appropriate range;

[0035] Image analysis: Analyze the X-ray imaging results, observe and record the smallest structure that can be clearly distinguished;

[0036] Resolution Determination: The spatial resolution of a system is calculated and determined by determining the minimum number of structures that can be clearly resolved.

[0037] Preferably, in step S6, the steps of the indirect method are as follows:

[0038] Get edge grayscale data: select an edge area from the X-ray image and read the grayscale value data on both sides of the area;

[0039] Smoothing: Smoothing the collected edge gray value data to reduce the impact of noise and errors;

[0040] Calculate the edge spread function ESF: Based on the smoothed data, calculate the edge spread function ESF, which describes the change of light intensity at the edge with distance;

[0041] Calculate the line spread function LSF: Perform differential processing on the ESF to obtain the line spread function LSF, which represents the response of the system at different spatial frequencies; the calculation formula is as follows: LSF(f) = d[ESF(f) / dx;

[0042] Calculate the modulation transfer function MTF: Perform Fourier transform on the LSF to obtain the modulation transfer function MTF, which quantitatively describes the response characteristics of the system in the spatial frequency domain; the calculation formula is as follows:

[0043] Resolution determination: Through the MTF curve, determine the number of line pairs corresponding to when the MTF drops to a certain threshold, and use this to calculate the spatial resolution of the system.

[0044] Compared with the prior art, the technical effects and advantages of the present invention are:

[0045] The method for regulating the radiation photoluminescence properties of silver-doped phosphate glass, the preparation process of Ag-PG silver-doped phosphate glass includes the steps of precise mixing of raw materials, high-temperature melting, rapid quenching and heat treatment. This preparation method can ensure that Ag + The ions are evenly distributed in the glass, resulting in a stable RPL signal under X-ray irradiation. + The ions are excited by X-rays to form Ag 0 and Ag 2+ Two types of luminescence centers. When these luminescence centers are excited by ultraviolet light, they emit visible light of a certain wavelength, which allows the stored X-ray information to be read.

[0046] By optimizing the internal structure of Ag-PG, the attenuation of X-ray image information can be reduced, thereby ensuring imaging stability. In addition, Ag-PG can erase the luminescence center generated after X-ray irradiation by heating and other methods, thereby achieving multiple imaging. Ag-PG has a high transmittance to visible light, which helps to reduce light scattering and thus improve imaging resolution. At the same time, the light scattering inside Ag-PG is small, which is conducive to achieving high spatial resolution X-ray imaging.

[0047] By optimizing factors such as the doping concentration and preparation process of Ag-PG, the radiation photoluminescence properties of Ag-PG can be effectively regulated, so that it has higher transmittance, higher spatial resolution and better long-term stability, thereby meeting the needs of different application scenarios, such as X-ray imaging, non-destructive testing and biological imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 The present invention is a flow chart for preparing the silver-doped phosphate glass;

[0049] Figure 2 RPL spectra of Ag-PG before and after X-ray irradiation;

[0050] Figure 3 This is the fluorescence decay curve of Ag-PG irradiated by X-rays at 450nm;

[0051] Figure 4 is the fluorescence decay curve of Ag-PG irradiated by X-ray at 650nm;

[0052] Figure 5 The actual pictures of Ag-PG with different irradiation times under 365nm ultraviolet light excitation of the present invention;

[0053] Figure 6 This is a diagram of the recycling process of Ag-PG under 365nm ultraviolet light;

[0054] Figure 7This is the RPL strength cycle test result diagram of Ag-PG;

[0055] Figure 8 The photos are of Ag-PG over-X-ray irradiation and repair process under visible light and 365nm UV light;

[0056] Fig. 9 Schematic diagram of the X-ray imaging and readout measurement device of Ag-PG;

[0057] Fig.10 The relationship curve between the RPL intensity of Ag-PG placed in the natural environment and the storage time (RPL stability);

[0058] Fig.11 X-ray imaging images on Ag-PG using 0.9 and 0.7 μm micro-resolution plates;

[0059] Fig.12 MTF curves for X-ray imaging using Ag-PG; DETAILED DESCRIPTION

[0060] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0061] The following is combined with Figure 1-12 To further explain this application in detail,

[0062] The present application embodiment discloses a method for regulating the radiation photoluminescence properties of silver-doped phosphate glass, comprising the following steps:

[0063] S1. Material preparation and doping: Select appropriate proportion of sodium hexametaphosphate Na6O 18 P6, aluminum dihydrogen phosphate Al(H2PO4)3 and silver chloride AgCl are fully mixed, and then the mixture is placed in a high-temperature reactor to melt L and cool and anneal to obtain Ag-PG. The prepared Ag-PG is cut into the required size and double-mirror polished to make its surface smooth to improve its optical transmittance, thereby optimizing the spatial resolution of X-ray imaging. The concentration of doped AgCl is controlled to control the Ag 0 and Ag 2+ The content of , thus affecting its RPL intensity and decay time;

[0064] S2. X-ray irradiation: Expose the polished Ag-PG to an X-ray source to record X-ray information. The irradiation dose of the sample is regulated by controlling the current and voltage of the X-ray source to facilitate subsequent regulation and imaging;

[0065] S3, heat treatment optimization: heat treatment of the prepared Ag-PG to enhance its RPL strength;

[0066] S4, RPL excitation: by irradiating Ag-PG with ultraviolet light, its RPL is stimulated to emit light, thereby reading the stored X-ray information;

[0067] S5. Material performance test: PL spectrum test is performed on the Ag-PG after different regulation steps to evaluate its luminescence performance. The test parameters include luminescence curve and decay time;

[0068] S6. X-ray imaging test: X-ray imaging test is performed on the Ag-PG after different regulation steps to evaluate its imaging performance. The test parameters include spatial resolution. The X-ray imaging test uses direct and indirect methods to test and verify the spatial resolution of Ag-PG.

[0069] S7. Performance optimization and repeated experiments: Based on the test results, the RPL performance and X-ray imaging performance of Ag-PG are optimized, including adjusting the doping concentration, heat treatment temperature and irradiation conditions; and the stability and repeatability of the control method are verified through repeated experiments;

[0070] S8. Reuse of Ag-PG: After X-ray irradiation and heat treatment, the Ag-PG is annealed and heated at 400°C for 2 hours to eliminate the RPL color center and other irradiation damage and restore its initial state for reuse. The annealed Ag-PG is re-irradiated with X-rays to record new X-ray information to achieve the recycling of Ag-PG.

[0071] like Figure 1 The preparation process of Ag-PG silver-doped phosphate glass is shown in the figure. First, sodium hexametaphosphate Na6O 18P6, aluminum dihydrogen phosphate Al(H2PO4)3 and silver chloride AgCl are mixed completely and evenly according to Na:Al:Ag=70:30:1, and then heated in a muffle furnace. The muffle furnace is heated from 25°C to 600°C at 5°C / min and kept at 600°C for 1 hour. The purpose is to slowly discharge the gas between the gaps of the powder to prevent the mixture from splashing due to rapid heating. Put it into a high-temperature reactor for melting and heat it to 1300°C, and keep it warm for 2h to make the raw materials completely melted and evenly mixed. Then, the molten Ag-PG is transferred to a preheated graphite mold at 420°C, and after quenching from melting to solid, it is kept warm in a muffle furnace at 420°C for 30 hours. Finally, the Ag-doped phosphate glass is cooled to 25°C, cut into Ag-PG sheets, and double-mirror polished into samples to prepare Ag-PG sheets (round or square).

[0072] For high-quality X-ray detection and imaging, the PL spectra of Ag-PG before and after X-ray irradiation are as follows: Figure 2 As shown in the figure, the horizontal axis is wavelength and the vertical axis is RPL intensity. The excitation wavelength is 337nm, which is consistent with the commercial Ag-PG dosimeter. Figure 2 As shown, a weak luminescence peak is observed at a wavelength of 450 nanometers, while at a wavelength of 650 nanometers, a luminescence area with significant brightness is shown, which becomes the central band of the entire luminescence spectrum. Figure 3 and Figure 4 The fluorescence decay curves of the two PL peaks of Ag-PG are shown respectively, with the horizontal axis representing time and the vertical axis representing counts. The excitation wavelength is 337 nm, and the corresponding emission wavelengths are 450 nm and 650 nm, respectively.

[0073] The two RPL peak intensities I(t) can be expanded through three exponential decay components, where τ1, τ2, and τ3 represent the decay lifetimes of different luminescence components, and parameters A1, A2, and A3 are weighting factors. The fitting formula is as follows: Through this fitting, the decay time of the emission peak centered at 450nm has three components: 1.49μs, 19.19μs, and 55.65μs, with an average decay time of 25.29μs. At the same time, the decay time of the emission peak centered at 650nm also has three components: 4.50μs, 16.16μs, and 205.03μs, with an average decay time of 19.83μs. For the 450nm light emission, the decay time (~1.49μs) is at least likely to be related to Ag. 2+ The decay time (~19.19 μs) may be related to Ag + For orange emission (~650nm), the decay time is relatively close to that of Ag in GD-450. 2+ Decay time of the emission.

[0074] In order to ensure the accuracy of radiation detection and X-ray information quantification, it is particularly important to study the linear relationship between RPL material strength and ionizing radiation intensity. Therefore, we conducted an in-depth study on the relationship between RPL intensity and irradiation time. In the experiment, we used the same Ag-PG material and tested it at different irradiation times. Figure 5 As shown, under the irradiation of 365 nm ultraviolet light, when the working voltage and current are maintained at 80 kV and 4 mA respectively, we can clearly observe that the luminescence intensity of Ag-PG gradually increases with the extension of irradiation time.

[0075] Furthermore, in order to study the stability and cyclic performance of Ag-PG, we took a series of measures. Since the diffusion rate of electrons in Ag-PG is higher than that of holes, we decided to accelerate the diffusion of holes by heating. Specifically, we heated Ag-PG to 100℃ and kept it warm for 1 hour. Figure 6 It can be clearly seen that after heat treatment, the emission peak of Ag-PG at 650nm is enhanced, which indicates that heat treatment is conducive to the accumulation effect of Ag-PG.

[0076] In addition, we also found that when Ag-PG is annealed at a higher temperature, the electrons can obtain enough energy to return to the valence band, which will lead to the disappearance of RPL luminescence. Based on this finding, we successfully eliminated the effect of X-ray radiation on Ag-PG by heat treating it at 400℃ for 2 hours, restoring it to the state before X-ray irradiation.

[0077] Finally, we tested Ag-PG with 20 cycles of X-ray irradiation and heating. Figure 7 shown. Figure 7 The horizontal axis represents the number of cycles, and the vertical axis represents the luminescence intensity. The test results show that the RPL intensity of Ag-PG does not show obvious attenuation during the whole process. This result strongly proves that Ag-PG can achieve repeatable recording of X-ray image information on the same medium through higher sample heating temperature, thus providing a reliable material basis for radiation detection and quantification of X-ray information.

[0078] For Ag-PG, doped Ag + Uniformly and stably exists in Ag-PG, and Ag3PO4 can be regarded as Ag + and PO4 3- When X-rays irradiate glass, primary electrons are generated by photoelectric absorption. Primary electrons can excite many secondary electrons generated by electromagnetic interactions such as Coulomb scattering. Their number is proportional to the incident energy of ionizing radiation. 3- Loss of an electron and formation of a "hole" (hPO42- ). Therefore, along the path of X-ray irradiation, many electron-hole pairs are generated inside Ag-PG. 3- The electrons released from the Ag + Combined to form Ag 0 On the other hand, Ag + Will be with PO4 3- (at PO4 3- The "hole" formed after losing an electron) combines, and then a "hole" is obtained and converted into Ag 2+ , Ag 0 and Ag 2+ All of them can be the luminescence center in Ag-PG. The process of luminescence center generation can be expressed by the following formula:

[0079]

[0080] Ag + +e - →Ag 0 (Electronic Trap)

[0081]

[0082] After X-ray irradiation, the Ag + With PO4 3- and hPO4 2- (By P.O. 3- The electrons and holes released by the formation of Ag 0 and Ag 2+ When these luminescent centers are excited by 337nm ultraviolet light, Ag 0 and Ag 2+ The electrons in the Ag are excited to a higher energy level or conduction band, and emit light in the process of returning to their original energy level. In the whole process, since the energy obtained by the electrons from the ultraviolet light is not enough to escape from the luminescent center, the Ag 0 and Ag 2+ Will not return to Ag + state, the X-ray information stored in the Ag-PG can be read repeatedly.

[0083] In addition, in order to fully evaluate the performance of Ag-PG under excessive irradiation and its recovery ability, we conducted a series of experiments to explore the effects of irradiation damage and its repair by heating. Specifically, we first tested the irradiation damage caused by Ag-PG under excessive irradiation conditions, and then we tried to erase the excess X-ray information by heating to achieve the repair of Ag-PG. This series of tests not only helped us understand the stability of Ag-PG under extreme conditions, but also verified that heating treatment is an effective means to reverse the changes caused by irradiation and restore the functionality of the material. Figure 8 The photo shows the over-X-ray irradiation and repair process of Ag-PG under visible light and ultraviolet light (365nm). When Ag-PG is exposed to a large dose of X-ray radiation, it will cause the formation of color centers in Ag-PG, that is, the defect site will produce selective absorption of visible light and make the crystal colored, such as Figure 8 (2), in addition, it will produce bright orange light under ultraviolet light excitation, such as Figure 8 (6) If Ag-PG is annealed at 400℃ for 2h, the color centers generated by Ag-PG will disappear and Ag-PG will return to its original state, as shown in Figure 8 (3) and Figure 8 (7) As shown. Under secondary X-ray irradiation, RPL phenomenon can still occur in Ag-PG, such as Figure 8 (8) This shows that the color center inside the Ag-PG caused by over-irradiation will not cause permanent damage to the Ag-PG, and it can still be restored to its original state through heat treatment (annealing at 400°C), but the generated color center will affect the accuracy of the readout system in reading the RPL intensity.

[0084] To characterize the spatial resolution capability of the X-ray imaging system, the spatial resolution of Ag-PG was tested using both direct and indirect methods. The direct test method involves performing X-ray scanning imaging of a standard component with a periodic structure of different spacings and analyzing the periodic image so that the maximum number of distinguishable stripes or circular holes determines the spatial resolution. This method can measure the spatial resolution of the system directly from the X-ray image. We used Ag-PG as an X-ray imaging medium to image a square-hole gold mesh under a transmission electron microscope and intuitively demonstrated the X-ray imaging capability of Ag-PG. Fig.10 The schematic diagram of the X-ray imaging measurement device is shown in Figure 1. The target material used in the X-ray source is a chromium target, and the operating voltage and current are 20 kV and 18 mA respectively. Fig. 9 This is a view of a square hole gold grid (2000 hole grid) under an optical microscope. Fig.10The X-ray imaging test device shown in the figure uses Ag-PG as the X-ray imaging medium to perform X-ray imaging on a square-hole gold grid (2000-hole grid). The X-ray image of the square-hole gold grid with 2000 holes, a pore size of 7.5μm, and a rib width of 5.0μm is clearly visible, indicating that using Ag-PG as the X-ray imaging medium can achieve micron-level resolution. The RPL intensity of Ag-PG is shown in Fig.10 As shown, the horizontal axis is storage time and the vertical axis is RPL intensity. After 300 days of exposure to air, it still has high humidity stability and the RPL intensity has almost no attenuation. Therefore, Ag-PG can be used as an X-ray imaging medium to store X-ray image information for a long time and achieve micron-level imaging resolution.

[0085] In order to explore the ultimate spatial resolution of Ag-PG, a micrometer resolution X-ray plate (JIMA RTRC-02, Japan Testing Instruments Manufacturers Association) was used to evaluate the spatial resolution of Ag-PG. The plate was irradiated at the 4B9A beamline at the Beijing Synchrotron Radiation Facility (BSRF). The overall X-ray microscope image of the micrometer resolution plate is shown in Figure 2. Fig.11 As shown in the figure, the horizontal line of "0.9μm" is very clear, and the horizontal line of "0.7μm" can also be identified. The test results further show that the ultimate spatial resolution of Ag-PG can reach sub-micron, exceeding the highest level reported for Ag-PG in X-ray imaging.

[0086] An indirect method is used to quantitatively characterize the spatial resolution of Ag-PG. The indirect test method is also called the modulation transfer function method. By reading the edge of the X-ray image and collecting the grayscale value data on both sides of the edge, the knife edge method is used to judge the spatial resolution of Ag-PG. The knife edge method is a common method for evaluating the spatial resolution of an X-ray imaging system using MTF. After smoothing the grayscale value data on both sides of the edge, the edge spread function (ESF) is obtained, and then the Modulation Transfer Function (MTF) of the entire X-ray imaging system can be obtained through the Fourier transform of the line spread function (LSF). The calculation formula is as follows:

[0087] LSF(f)=d[ESF(f)] / dx

[0088]

[0089] like Fig.12As shown in the figure, the horizontal axis is the spatial frequency, and the MTF curve of Ag-PG is calculated. When the MTF drops to 0.2, the corresponding line pair is 730lp / mm. The results show that the spatial resolution reaches the sub-micron level, which is consistent with the X-ray imaging results observed by the direct method.

[0090] The present invention finds that Ag-PG can generate visible light under ultraviolet light excitation after X-ray irradiation, and this property enables it to be used for X-ray imaging; Ag-PG has good chemical stability, which means that it can store X-ray image information for a long time without being degraded by environmental factors; Ag-PG has a high transmittance to visible light, which helps to reduce light scattering, thereby improving imaging resolution; Ag-PG can remove the luminescent centers generated after X-ray irradiation by heating and other methods, thereby achieving multiple imaging.

[0091] By regulating the RPL characteristics of Ag-PG, the imaging resolution can be improved, so that the microstructure can be better observed. By optimizing the internal structure of Ag-PG, the attenuation of X-ray image information can be reduced, thereby ensuring imaging stability. By optimizing the doping concentration, heat treatment temperature and irradiation conditions of Ag-PG, its RPL performance can be further improved, thereby improving the clarity and accuracy of X-ray imaging. The multi-layer X-ray image storage function of Ag-PG makes it possible to achieve three-dimensional imaging, which is of great significance for the observation and analysis of internal details of complex structures. Through the above regulation methods, the RPL characteristics of Ag-PG can be fully utilized to improve the quality and efficiency of X-ray imaging, thereby promoting the widespread application of X-ray imaging technology in multiple fields.

[0092] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for regulating the radiation photoluminescence properties of silver-doped phosphate glass, characterized in that: The steps include: S1. Material preparation and doping: Select appropriate proportion of sodium hexametaphosphate Na6O 18 P6, aluminum dihydrogen phosphate Al(H2PO4)3 and silver chloride AgCl are fully mixed, and then the mixture is placed in a high-temperature reactor to melt, and then cooled and annealed to obtain Ag-PG. The prepared Ag-PG is cut into the required size and double-mirror polished to make its surface smooth to improve its optical transmittance, thereby optimizing the spatial resolution of X-ray imaging. The concentration of AgCl doped is controlled to control the Ag 0 and Ag 2+ The content of , thus affecting its RPL intensity and decay time; S2. X-ray irradiation: Expose the polished Ag-PG to an X-ray source to record X-ray information. The irradiation dose of the sample is regulated by controlling the current and voltage of the X-ray source to facilitate subsequent regulation and imaging; S3, heat treatment optimization: heat treatment of the prepared Ag-PG to enhance its RPL strength; S4, RPL excitation: by irradiating Ag-PG with ultraviolet light, its RPL is stimulated to emit light, thereby reading the stored X-ray information; S5. Material performance test: PL spectrum test is performed on Ag-PG after different regulation steps to evaluate its luminescence performance. The test parameters include luminescence curve and decay time; S6. X-ray imaging test: X-ray imaging test is performed on the Ag-PG after different regulation steps to evaluate its imaging performance. The test parameters include spatial resolution. The X-ray imaging test uses direct and indirect methods to test and verify the spatial resolution of Ag-PG. S7. Performance optimization and repeated experiments: Based on the test results, the RPL performance and X-ray imaging performance of Ag-PG are optimized, including adjusting the doping concentration, heat treatment temperature and irradiation conditions; and the stability and repeatability of the control method are verified through repeated experiments; S8. Reuse of Ag-PG: After X-ray irradiation and heat treatment, the Ag-PG is annealed and heated at 400°C for 2 hours to eliminate the RPL color center and other irradiation damage and restore its initial state for reuse. The annealed Ag-PG is re-irradiated with X-rays to record new X-ray information to achieve the recycling of Ag-PG.

2. The method for controlling the radiation photoluminescence characteristics of silver-doped phosphate glass according to claim 1, characterized in that: The preparation of Ag-PG in step 1 comprises the following steps: S1.

1. First, sodium hexametaphosphate Na6O 18 P6, aluminum dihydrogen phosphate Al(H2PO4)3 and silver chloride AgCl are uniformly mixed in a ratio of Na:Al:Ag=70:30:1 and put into a crucible; S1.

2. Then put the crucible containing the mixed materials into a muffle furnace for preheating and degassing. The muffle furnace is heated from 25°C to 600°C at 5°C / min and kept at 600°C for 1 hour. Then, it is transferred to a high-temperature reaction furnace at 1300°C for melting for 2 hours to completely melt the raw materials and mix them evenly. S1.3, then, the molten Ag-PG was cast into a graphite mold preheated at 420°C, and after cooling and solidification, it was placed in a muffle furnace at 420°C for annealing for 30 hours; S1.

4. Finally, the cooled Ag-PG is taken out and cut into Ag-PG sheets of specified size, and then double-mirror polished to obtain Ag-PG circular sheets or Ag-PG square sheets.

3. The method for controlling the radiation photoluminescence characteristics of silver-doped phosphate glass according to claim 1, characterized in that: In step S3, Ag-PG is heat-treated at 100° C. for 1 hour.

4. The method for controlling the radiation photoluminescence characteristics of silver-doped phosphate glass according to claim 1, characterized in that: After X-ray irradiation in step S2, Ag has been formed inside the Ag-PG material. 0 and Ag 2+ There are two stable luminescence centers. Ultraviolet light excites the electrons in the luminescence center to the conduction band, and they emit light in the process of transitioning back to the luminescence center.

5. The method for controlling the radiation photoluminescence characteristics of silver-doped phosphate glass according to claim 1, characterized in that: In step S4, ultraviolet excitation is used to read the stored X-ray information, and the PL spectrum and fluorescence decay curve are analyzed to evaluate the radiation photoluminescence characteristics of Ag-PG and perform necessary optimization.

6. The method for controlling the radiation photoluminescence characteristics of silver-doped phosphate glass according to claim 1, characterized in that: The luminescence peak intensity and decay time in the RPL spectrum in step S1 are described by the following formula: Among them, I(t) represents the RPL intensity at time t; τ1, τ2, τ3 represent the decay lifetimes of different luminous components; and parameters A1, A2, A3 are weighting factors.

7. The method for controlling the radiation photoluminescence characteristics of silver-doped phosphate glass according to claim 1, characterized in that: In step S6, the direct method steps are as follows: Prepare standard test parts: Prepare periodic standard parts with known spacing and structure, such as square hole gold grids, for X-ray imaging tests; X-ray scanning imaging: Use an X-ray source to scan and image the square hole gold grid, ensuring that the operating voltage and current of the X-ray source are set within the appropriate range; Image analysis: Analyze the X-ray imaging results, observe and record the smallest structure that can be clearly distinguished; Resolution Determination: The spatial resolution of a system is calculated and determined by determining the minimum number of structures that can be clearly resolved.

8. The method for controlling the radiation photoluminescence characteristics of silver-doped phosphate glass according to claim 1, characterized in that: In step S6, the steps of the indirect method are as follows: Get edge grayscale data: select an edge area from the X-ray image and read the grayscale value data on both sides of the area; Smoothing: Smoothing the collected edge gray value data to reduce the impact of noise and errors; Calculate the edge spread function ESF: Based on the smoothed data, calculate the edge spread function ESF, which describes the change of light intensity at the edge with distance; Calculate the line spread function LSF: Perform differential processing on the ESF to obtain the line spread function LSF, which represents the response of the system at different spatial frequencies; the calculation formula is as follows: LSF(f) = d[ESF(f)] / dx; Calculate the modulation transfer function MTF: Perform Fourier transform on the LSF to obtain the modulation transfer function MTF, which quantitatively describes the response characteristics of the system in the spatial frequency domain; the calculation formula is as follows: Resolution determination: Through the MTF curve, determine the number of line pairs corresponding to when the MTF drops to a certain threshold, and use this to calculate the spatial resolution of the system.

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