Preparation method of X-ray fluorescent screen and X-ray fluorescent screen

Abstract

The invention discloses a preparation method of an X-ray fluorescent screen and the X-ray fluorescent screen. The preparation method comprises the following steps: S1, pretreatment: cleaning and drying a micro-channel structural body; the micro-channel structural body is provided with a plurality of through micro-channels, and the micro-channel structural body is made of glass; s2, micro-channel film plating: plating a reflecting film on the side wall of the micro-channel; s3, preparing turbid liquid: mixing fluorescent material particles, a carrier solvent and a surfactant, and dispersing to obtain the turbid liquid; s4, filling the micro-channel; s5, repeated filling is carried out; s6, post-processing: carrying out surface cleaning and packaging on the micro-channel structure body; the X-ray fluorescent screen is prepared by adopting the preparation method. The X-ray fluorescent screen comprises a micro-channel structural body, the micro-channel structural body is provided with a plurality of through micro-channels arranged in an array, and the micro-channels are filled with fluorescent material particles. The glass micro-channel structural body is filled with the fluorescent material particles, so that the resolution ratio and the fluorescence transmission efficiency of the X-ray fluorescent screen are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of X-ray detection, and in particular to a method for preparing an X-ray fluorescent screen and the X-ray fluorescent screen. Background Art

[0002] With the development and application of various X-ray imaging technologies such as non-destructive testing, safety inspection, and medical diagnosis, X-ray detectors have been widely used. Among the widely used hard X-ray detectors, indirect X-ray detectors are the mainstream. This type of detector first converts X-rays into fluorescent signals through scintillators, and then converts them into electrical signals through coupled photodetectors and reads out the signals. Resolution is one of the core indicators of X-ray detectors. High-resolution detectors are increasingly widely used in non-destructive testing of modern devices. The main factors affecting the resolution of indirect X-ray detectors are the fluorescent screen and the pixel size of the photodetector. The latter can currently reach a size of microns, which is much lower than the resolution of the currently widely used indirect X-ray detectors. Therefore, the characteristics of the fluorescent screen determine the resolution of the X-ray detector.

[0003] At present, one of the main ways to realize a scintillator fluorescent screen with high resolution is to make a structured fluorescent screen, that is, to arrange the scintillator materials in a pixel-like manner, so that the fluorescence formed in adjacent scintillators does not interfere with each other during the transmission to the photodetector, thus avoiding the crosstalk of signals. In the implementation process, if the fluorescent material is made into a crystal column shape, the crosstalk of signals can be avoided to a certain extent. Furthermore, the fluorescent material can be filled into mutually isolated microchannel structures, which can fundamentally avoid the crosstalk of fluorescent signals. The microchannel structure currently used is made on a silicon substrate using semiconductor dry etching or wet etching. When these technologies realize microchannel structures with large depth or high aspect ratio, it is difficult to control the surface roughness of the microchannel sidewalls. Since a large part of the fluorescence generated by X-rays will be reflected by the sidewalls when transmitting in the microchannel, the high surface roughness of the sidewalls will reduce the reflectivity, thereby affecting the emission efficiency of the fluorescence. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method for preparing an X-ray fluorescent screen and the X-ray fluorescent screen.

[0005] The technical solution adopted by the present invention to solve the technical problem is: a method for preparing an X-ray fluorescent screen, comprising the following steps:

[0006] S1. Pretreatment: cleaning and drying the microchannel structure; the microchannel structure is provided with a plurality of through microchannels, and the microchannel structure is made of glass;

[0007] S2, microchannel coating: coating the side wall of the microchannel with a reflective film;

[0008] S3, preparing a suspension: mixing fluorescent material particles, a carrier solvent and a surfactant, and dispersing them to obtain a suspension;

[0009] S4, filling the microchannel: under vacuum, the suspension is covered on the surface of the microchannel structure, and then left to stand or external force is applied, so that the fluorescent material particles settle into the microchannel;

[0010] S5, repeat filling: check whether the fluorescent material particles in the microchannel are filled to the target thickness, if not, repeat step S4, if yes, proceed to the next step;

[0011] S6. Post-processing: cleaning and packaging the surface of the microchannel structure to obtain an X-ray fluorescent screen.

[0012] Furthermore, in step S1, an organic solvent and water are used for cleaning, and the organic solvent is anhydrous ethanol or acetone; the microchannel structure is ultrasonically cleaned for 5-15 minutes.

[0013] Furthermore, in step S2, coating is performed by evaporation, sputtering or atomic layer deposition; the reflective film is made of aluminum or silver.

[0014] Furthermore, in step S2, a protective film is plated on the surface of the reflective film, the protective film is made of silicon dioxide or aluminum oxide, and the thickness of the protective film is 20-150 nm.

[0015] Furthermore, in step S3, the fluorescent material particles are gadolinium oxysulfide or cesium iodide, and the average particle size of the fluorescent material particles is 0.1-10 μm.

[0016] Furthermore, in step S3, the volume ratio between the surfactant and the carrier solvent is 1:(50-200).

[0017] Furthermore, in step S3, the surfactant is DMF or DMSO or N-methylpyrrolidone; and / or the carrier solvent is anhydrous ethanol or isopropanol or acetone.

[0018] Furthermore, in step S4, the external force applied is vibration or centrifugation of the microchannel structure; there is a height difference between the liquid surface of the suspension and the surface of the microchannel structure, and the height difference is 2-20 cm.

[0019] Furthermore, in step S6, the fluorescent material particles remaining on the surface of the microchannel structure are removed, and then the surface of the microchannel structure is covered with an organic film layer, which is a polyester film layer, a polyethylene film layer, a polypropylene film layer or a polyether film layer.

[0020] An X-ray fluorescent screen is made by the above-mentioned method for making an X-ray fluorescent screen; the X-ray fluorescent screen comprises a microchannel structure, the microchannel structure is provided with a plurality of microchannels which are connected and arranged in an array, and the microchannels are filled with X-ray fluorescent material particles.

[0021] Beneficial effects of the present invention:

[0022] The present invention proposes to use a microchannel structure as a structural carrier of an X-ray fluorescent screen, and fill fluorescent material particles into the through microchannels, thereby realizing an X-ray fluorescent screen with both high resolution and higher fluorescence transmission efficiency. Among them, before the fluorescent material particles are filled, a carrier solvent and a surfactant are first mixed with the fluorescent material particles, so that the fluorescent material particles are efficiently deposited in the microchannel. The surface roughness of the inner wall of the glass microchannel of the present invention is much better than the surface roughness of the microchannel formed by etching on the existing silicon substrate, thereby improving the fluorescence transmission efficiency. In addition, the length (or depth) of the microchannel through the microchannel structure can be arbitrarily selected, or the target filling thickness of the fluorescent material particles can be arbitrarily selected, and a microchannel structure with a large depth is expected to be used to achieve the detection of higher energy X-rays.

[0023] The X-ray fluorescent screen produced by the present invention has the advantage of higher fluorescence reflection efficiency of the inner wall of the microchannel while maintaining high resolution capability compared with the X-ray fluorescent screen based on silicon-based microchannel array. When used in a high-resolution X-ray imaging system, it helps to reduce the X-ray radiation dose. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0025] Figure 1 is a surface SEM image of the microchannel structure of Example 1 of the present invention;

[0026] Figure 2 is a SEM image of the X-ray fluorescent screen of Example 1 of the present invention;

[0027] Figure 3 is a resolution test chart of the X-ray fluorescent screen of Example 1 of the present invention;

[0028] Figure 4 is a SEM image of the X-ray fluorescent screen of Comparative Example 1 of the present invention;

[0029] Figure 5 This is a resolution test chart of the X-ray fluorescent screen of comparative example 1 of the present invention. DETAILED DESCRIPTION

[0030] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the present invention will be further described in detail below in conjunction with embodiments. The embodiments are only used to explain the present invention and do not constitute a limitation on the protection scope of the present invention.

[0031] The present invention provides a method for preparing an X-ray fluorescent screen, comprising the following steps:

[0032] S1. Pretreatment: cleaning and drying the microchannel structure; the microchannel structure is provided with a plurality of through microchannels, and the microchannel structure is made of glass.

[0033] Specifically, organic solvent and water are used for cleaning, the organic solvent can be anhydrous ethanol or acetone, and the water can be pure water. Cleaning can be ultrasonic cleaning of the microchannel structure for 5-15 minutes. In some embodiments, the microchannel structure is a glass microchannel plate (a commercial product), which has a glass microchannel array. The glass microchannel plate is often used to make an electron multiplier device, which has very high requirements for the surface roughness of the inner wall of the microchannel, usually at the nanometer level or sub-nanometer level. The surface roughness of the inner wall of the microchannel in the glass microchannel structure used in the present invention is 0.3-50nm, which helps to improve the resolution and fluorescence transmission efficiency of the fluorescent screen. The specific surface roughness can be flexibly selected according to actual needs, and the present invention is not limited. The period of the microchannel (i.e., the central axis spacing of adjacent microchannels) is 6-120μm, the aperture is 5-100μm, and the depth is 100-2000μm.

[0034] S2, Microchannel Coating: Coating a reflective film on the side wall of the microchannel.

[0035] Specifically, the coating is performed by evaporation, sputtering or atomic layer deposition. It can be understood that evaporation technology, sputtering technology and atomic layer deposition technology are all prior arts, and the process parameters of the coating can be selected according to actual needs, and the present invention does not specifically limit them. By coating the side wall of the microchannel with a reflective film, the reflection efficiency of the visible light converted by X-rays can be effectively improved.

[0036] Preferably, the reflective film is made of aluminum or silver. If the reflective film is made of aluminum, the surface of the aluminum will oxidize in the air to form aluminum oxide, thereby protecting the reflective film. A protective film may also be plated on the surface of the reflective film, and the protective film may be made of silicon dioxide. If the reflective film is made of silver, a protective film is plated on the surface of the reflective film to prevent oxidation of the reflective film, and the protective film may be made of silicon dioxide or aluminum oxide. The thickness of the above-mentioned protective film is 20-150nm, for example, it may be 20nm, 50nm, 80nm, 100nm, 120nm, 150nm, etc. Among them, the protective film can choose the same coating method as the reflective film, or other different coating methods, which can be flexibly selected according to actual needs.

[0037] S3. Prepare suspension: mix fluorescent material particles, carrier solvent and surfactant, and disperse them to obtain suspension.

[0038] Specifically, fluorescent material particles are selected as filling materials for converting X-rays into visible light. The fluorescent material particles are gadolinium oxysulfide (GOS) or cesium iodide (CsI(Tl)). The average particle size of the fluorescent material particles is 0.1-10 μm, and can be 0.1, 0.5 μm, 1 μm, 3 μm, 5 μm, 8 μm, 10 μm, etc. The volume ratio between the surfactant and the carrier solvent is 1:(50-200), and can be 1:50, 1:75, 1:100, 1:150, 1:200, etc. The surfactant can be DMF (dimethylformamide) or DMSO (dimethyl sulfoxide) or N-methylpyrrolidone. One of the functions of the surfactant is to enable the fluorescent material particles entering the microchannel to adhere to the side wall of the microchannel and not easily detach. Another function is to disperse the fluorescent material particles to prevent them from agglomerating before entering the microchannel. The carrier solvent can be anhydrous ethanol, isopropanol, or acetone, or other solvents with certain volatility. Furthermore, the mixed solution of fluorescent material particles, carrier solvent and surfactant is ultrasonically dispersed or vibrationally dispersed to obtain a suspension in which the fluorescent material particles are evenly dispersed, wherein the dispersion process parameters can be selected according to actual needs and are not specifically limited in the present invention.

[0039] S4. Filling the microchannel: Under vacuum, the suspension is covered on the surface of the microchannel structure, and then left to stand or external force is applied, so that the fluorescent material particles settle into the microchannel.

[0040] Wherein, vacuum degree is higher than 0.3 standard atmospheric pressure, vacuum degree refers to the reading of vacuum gauge, and vacuum degree is higher than 0.3 standard atmospheric pressure, and it is not limited. Specifically, first microchannel structure is placed in a container, and then the suspension prepared in step S3 is injected into the container, there is a height difference between the liquid level of the suspension and the surface of the microchannel structure, and the height difference is preferably 2-20cm, and specifically can be 2cm, 3cm, 5cm, 8cm, 10cm, 15cm, 20cm, etc., so as to ensure that there are enough fluorescent material particles in the container, and more fluorescent material particles can be filled in the microchannel at one time. After the suspension is covered on the surface of the microchannel structure, it is left to stand for 1.5-2.5 hours or an external force is applied, so that the fluorescent material particles in the suspension are settled in the microchannel, wherein, applying an external force can be vibrating or centrifuging the microchannel structure, and its process parameters can be selected according to actual needs, and the present invention is not specifically limited.

[0041] S5, repeat filling: detect whether the fluorescent material particles in the microchannel are filled to the target thickness, if not, repeat step S4, if yes, proceed to the next step. The target thickness refers to the filling thickness of the fluorescent material particles in the microchannel, and the target thickness can be selected according to actual needs, and the present invention does not make a specific limitation.

[0042] Specifically, the distribution of fluorescent material particles in the microchannel of the microchannel structure is observed by scanning electron microscopy. If the filling thickness of the fluorescent material particles in the microchannel does not reach the target thickness, step S4 is repeated and the suspension prepared in step S3 is used to refill the microchannel until the filling thickness of the fluorescent material particles in the microchannel of the microchannel structure reaches the target thickness.

[0043] In some embodiments, the target thickness may be the length (or depth) of the microchannel, that is, the fluorescent material particles are filled in the microchannel, and step S5 is: detect whether the microchannel is filled with fluorescent material particles, if not, re-perform step S4, and if yes, proceed to the next step. Specifically, the distribution of fluorescent material particles in the microchannel of the microchannel structure is observed by scanning electron microscopy. If the microchannel is not filled with fluorescent material particles, that is, the filling is uneven or insufficient, step S4 is re-performed, and the suspension prepared in step S3 is used to re-fill until the microchannel of the microchannel structure is filled with fluorescent material particles.

[0044] S6. Post-processing: cleaning and packaging the surface of the microchannel structure to obtain an X-ray fluorescent screen.

[0045] Specifically, the fluorescent material particles remaining on the surface of the microchannel structure are removed, for example, by scraping off the particles with a tool, and then a high-transmittance organic film layer is covered on the surface of the microchannel structure. The organic film layer can be a polyester film layer (PET film), a polyethylene film layer (PE film), a polypropylene film layer (BOPP film) or a polyether film layer (PEEK film).

[0046] The present invention also proposes an X-ray fluorescent screen, which is made by the above-mentioned method for making an X-ray fluorescent screen, and the X-ray fluorescent screen includes a microchannel structure, and the microchannel structure is provided with a plurality of microchannels that are connected and arranged in an array, and the microchannels are filled with X-ray fluorescent material particles. Among them, the microchannel structure can be made of glass, such as a glass microchannel plate, which has a glass microchannel array. The X-ray fluorescent material particles can be gadolinium oxysulfide or cesium iodide, which are used to convert X-rays into visible light.

[0047] The present invention proposes to use a microchannel structure as a structural carrier of an X-ray fluorescent screen, and fill fluorescent material particles into the through microchannels, thereby realizing an X-ray fluorescent screen with both high resolution and higher fluorescence transmission efficiency. Among them, before the fluorescent material particles are filled, the carrier solvent and the surfactant are first mixed with the fluorescent material particles, so that the fluorescent material particles are efficiently deposited in the microchannel. The surface roughness of the inner wall of the glass microchannel of the present invention can be controlled within a few nanometers, which is much better than the surface roughness of the microchannel array formed by etching on the existing silicon substrate, thereby improving the fluorescence transmission efficiency. In addition, the length (or depth) of the microchannel through the microchannel structure can be arbitrarily selected during cutting and manufacturing, or the filling target thickness of the fluorescent material particles can be arbitrarily selected, and the microchannel structure with a large depth is expected to be used to achieve the detection of higher energy X-rays.

[0048] The X-ray fluorescent screen produced by the present invention fully utilizes the advantages of glass microchannel arrays that can be mass-produced and the low surface roughness of the inner wall of the glass microchannel. While maintaining high-resolution capability, it has a higher microchannel inner wall fluorescent reflection efficiency than the X-ray fluorescent screen based on the silicon-based microchannel array. When used in a high-resolution X-ray imaging system, it helps to reduce the X-ray radiation dose.

[0049] The following is described by specific examples:

[0050] Example 1

[0051] A method for preparing an X-ray fluorescent screen comprises the following steps:

[0052] S1. Pretreatment: Clean and dry the microchannel structure; the microchannel structure is provided with a plurality of through microchannels, and the microchannel structure is made of glass. Specifically, the microchannel structure is ultrasonically cleaned for 10 minutes using an organic solvent (anhydrous ethanol) and pure water. The microchannel structure has a glass microchannel array, the surface roughness of the inner wall of the microchannel is 3nm, the period of the microchannel is 25μm, the pore size is 21μm, and the depth is 500μm.

[0053] S2, microchannel coating: coating the side wall of the microchannel with a reflective film. Specifically, the coating is performed by physical evaporation, and the reflective film is made of aluminum. The surface SEM image of the microchannel structure after coating is as follows: Figure 1 shown.

[0054] S3, prepare suspension: mix fluorescent material particles, carrier solvent and surfactant, and disperse to obtain suspension. Specifically, the fluorescent material particles are GOS, and their average particle size is 2 μm. The volume ratio between the surfactant and the carrier solvent is 1:100, the surfactant is DMF, and the carrier solvent is anhydrous ethanol. Further, the mixed solution of fluorescent material particles, carrier solvent and surfactant is ultrasonically dispersed to obtain a suspension in which the fluorescent material particles are evenly dispersed.

[0055] S4, filling the microchannel: under vacuum, the suspension is covered on the surface of the microchannel structure, and then left to stand or external force is applied, so that the fluorescent material particles settle into the microchannel. Specifically, the vacuum degree is higher than 0.3 standard atmospheric pressure, the microchannel structure is first placed in a container, and then the suspension prepared in step S3 is injected into the container, the height difference between the liquid surface of the suspension and the surface of the microchannel structure is 3 cm, and then left to stand for 2 hours.

[0056] S5, repeated filling: Check whether the fluorescent material particles in the microchannel are filled to the target thickness. If not, repeat step S4. If yes, proceed to the next step. Specifically, observe the distribution of the fluorescent material particles in the microchannel of the microchannel structure through a scanning electron microscope. If it is found that the filling thickness of the fluorescent material particles in the microchannel does not reach the target thickness, repeat step S4 and refill with the suspension prepared in step S3 until the filling thickness of the fluorescent material particles in the microchannel of the microchannel structure reaches the target thickness.

[0057] S6, post-processing: cleaning and packaging the microchannel structure to obtain an X-ray fluorescent screen. Specifically, removing the fluorescent material particles remaining on the surface of the microchannel structure, and then covering the surface of the microchannel structure with an organic film layer (PET film).

[0058] An X-ray fluorescent screen is prepared by the above-mentioned method for preparing an X-ray fluorescent screen, the X-ray fluorescent screen comprises a microchannel structure, the microchannel structure is provided with a plurality of microchannels that are connected and arranged in an array, and the microchannels are filled with X-ray fluorescent material particles. The microchannel structure is made of glass, has a glass microchannel array, and the X-ray fluorescent material particles are GOS.

[0059] Example 2

[0060] A method for preparing an X-ray fluorescent screen comprises the following steps:

[0061] S1. Pretreatment: Clean and dry the microchannel structure; the microchannel structure is provided with a plurality of through microchannels, and the microchannel structure is made of glass. Specifically, the microchannel structure is ultrasonically cleaned for 5 minutes using an organic solvent (acetone) and pure water. The microchannel structure has a glass microchannel array, the surface roughness of the inner wall of the microchannel is 1 nm, the period of the microchannel is 15 μm, the pore size is 12 μm, and the depth is 400 μm.

[0062] S2, microchannel coating: coating the side wall of the microchannel with a reflective film. Specifically, the reflective film is made of silver by sputtering. Then, a protective film is coated on the surface of the reflective film. The protective film is made of aluminum oxide and has a thickness of 50 nm.

[0063] S3. Prepare a suspension: Mix the fluorescent material particles, the carrier solvent and the surfactant, and disperse them to obtain a suspension. Specifically, the fluorescent material particles are cesium iodide, and the average particle size is 1 μm. The volume ratio between the surfactant and the carrier solvent is 1:50, the surfactant is DMSO, and the carrier solvent is isopropanol. Further, the mixed solution of the fluorescent material particles, the carrier solvent and the surfactant is centrifugally dispersed to obtain a suspension in which the fluorescent material particles are evenly dispersed.

[0064] S4, filling the microchannel: under vacuum, the suspension is covered on the surface of the microchannel structure, and then left to stand or external force is applied, so that the fluorescent material particles settle into the microchannel. Specifically, the vacuum degree is 0.3 standard atmospheric pressure, the microchannel structure is first placed in a container, and then the suspension prepared in step S3 is injected into the container, the height difference between the liquid surface of the suspension and the surface of the microchannel structure is 5 cm, and then vibration is applied to the microchannel structure.

[0065] S5, repeated filling: Check whether the microchannel is filled with fluorescent material particles. If not, repeat step S4. If yes, proceed to the next step. Specifically, observe the distribution of fluorescent material particles in the microchannel of the microchannel structure through a scanning electron microscope. If it is found that the microchannel is not filled with fluorescent material particles, that is, the filling is uneven or insufficient, repeat step S4 and refill with the suspension prepared in step S3 until the microchannel of the microchannel structure is filled with fluorescent material particles.

[0066] S6, post-processing: cleaning and packaging the surface of the microchannel structure to obtain an X-ray fluorescent screen. Specifically, removing the fluorescent material particles remaining on the surface of the microchannel structure, and then covering the surface of the microchannel structure with an organic film layer (PE film).

[0067] An X-ray fluorescent screen is prepared by the above-mentioned preparation method of the X-ray fluorescent screen, the X-ray fluorescent screen comprises a microchannel structure, the microchannel structure is provided with a plurality of microchannels that penetrate and are arranged in an array, and the microchannels are filled with X-ray fluorescent material particles. The microchannel structure is made of glass, has a glass microchannel array, and the X-ray fluorescent material particles are cesium iodide.

[0068] Example 3

[0069] A method for preparing an X-ray fluorescent screen comprises the following steps:

[0070] S1. Pretreatment: Clean and dry the microchannel structure; the microchannel structure is provided with a plurality of through microchannels, and the microchannel structure is made of glass. Specifically, the microchannel structure is ultrasonically cleaned for 15 minutes using an organic solvent (acetone) and pure water. The microchannel structure has a glass microchannel array, the surface roughness of the inner wall of the microchannel is 3nm, the period of the microchannel is 25μm, the pore size is 21μm, and the depth is 900μm.

[0071] S2, microchannel coating: coating the side wall of the microchannel with a reflective film. Specifically, the reflective film is made of silver by atomic layer deposition. Then, a protective film is coated on the surface of the reflective film. The protective film is made of silicon dioxide and has a thickness of 120 nm.

[0072] S3. Prepare a suspension: Mix the fluorescent material particles, the carrier solvent and the surfactant, and disperse them to obtain a suspension. Specifically, the fluorescent material particles are cesium iodide, and the average particle size is 5 μm. The volume ratio between the surfactant and the carrier solvent is 1:200, the surfactant is N-methylpyrrolidone, and the carrier solvent is acetone. Further, the mixed solution of the fluorescent material particles, the carrier solvent and the surfactant is centrifugally dispersed to obtain a suspension in which the fluorescent material particles are evenly dispersed.

[0073] S4, filling the microchannel: under vacuum, the suspension is covered on the surface of the microchannel structure, and then left to stand or external force is applied, so that the fluorescent material particles settle into the microchannel. Specifically, the vacuum degree is 0.5 standard atmospheric pressure, the microchannel structure is first placed in a container, and then the suspension prepared in step S3 is injected into the container, the height difference between the liquid surface of the suspension and the surface of the microchannel structure is 10 cm, and then the microchannel structure is centrifuged.

[0074] S5, repeated filling: Check whether the microchannel is filled with fluorescent material particles. If not, repeat step S4. If yes, proceed to the next step. Specifically, observe the distribution of fluorescent material particles in the microchannel of the microchannel structure through a scanning electron microscope. If it is found that the microchannel is not filled with fluorescent material particles, that is, the filling is uneven or insufficient, repeat step S4 and refill with the suspension prepared in step S3 until the microchannel of the microchannel structure is filled with fluorescent material particles.

[0075] S6, post-processing: cleaning and packaging the surface of the microchannel structure to obtain an X-ray fluorescent screen. Specifically, removing the fluorescent material particles remaining on the surface of the microchannel structure, and then covering the surface of the microchannel structure with an organic film layer (BOPP film).

[0076] An X-ray fluorescent screen is prepared by the above-mentioned preparation method of the X-ray fluorescent screen, the X-ray fluorescent screen comprises a microchannel structure, the microchannel structure is provided with a plurality of microchannels that penetrate and are arranged in an array, and the microchannels are filled with X-ray fluorescent material particles. The microchannel structure is made of glass, has a glass microchannel array, and the X-ray fluorescent material particles are cesium iodide.

[0077] Comparative Example 1

[0078] The preparation method of the X-ray fluorescent screen of this comparative example is different from that of Example 1 in that in step S3 of this comparative example, the surfactant is oleic acid, and the remaining steps are the same. An X-ray fluorescent screen is prepared according to the preparation method of the X-ray fluorescent screen of this comparative example.

[0079] Comparative test:

[0080] The X-ray fluorescent screens prepared in Example 1 and Comparative Example 1 were subjected to SEM scanning electron microscope observation and resolution test. The test results are as follows: Figure 2 to Figure 5 The resolution test steps are as follows: place the X-ray fluorescent screen close to the visible light CCD (charge coupled device), and then place the resolution card for testing close to the X-ray fluorescent screen. When the X-ray source is turned on, the resolution card is projected on the X-ray fluorescent screen, and the X-ray fluorescent screen converts the X-rays into visible light and is received by the CCD.

[0081] Figure 2 This is a SEM image of the X-ray fluorescent screen of Example 1. It can be seen from the image that when DMF is used as a surfactant, the GOS particles are more densely packed in the microchannel; Figure 3 This is a resolution test chart of the X-ray fluorescent screen of Example 1. It can be seen from the chart that the resolution of the X-ray fluorescent screen reaches 10lp / mm, with good contrast and brightness. Figure 4This is a SEM image of the X-ray fluorescent screen of Comparative Example 1. It can be seen from the figure that GOS particles can also be successfully filled into the microchannel using oleic acid as a surfactant, but the particle filling is uneven and not full; Figure 5 This is a resolution test chart of the X-ray fluorescent screen of comparative example 1. It can be seen from the chart that the resolution of the X-ray fluorescent screen of comparative example 1 also reaches 10lp / mm, but the contrast and brightness are worse than those of the X-ray fluorescent screen of embodiment 1.

[0082] It can be understood that the above embodiments only express the preferred implementation modes of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the patent scope of the present invention. It should be pointed out that, for ordinary technicians in this field, the above technical features can be freely combined without departing from the concept of the present invention, and several deformations and improvements can be made, which all belong to the protection scope of the present invention. Therefore, all equivalent changes and modifications made to the scope of the claims of the present invention should belong to the scope covered by the claims of the present invention.

Claims

1. A method for preparing an X-ray fluorescent screen, characterized in that: The following steps are involved: S1. Pretreatment: cleaning and drying the microchannel structure; the microchannel structure is provided with a plurality of through microchannels, and the microchannel structure is made of glass; S2, microchannel coating: coating a reflective film on the side wall of the microchannel; S3, preparing a suspension: mixing fluorescent material particles, a carrier solvent and a surfactant, and dispersing them to obtain a suspension; S4, filling the microchannel: under vacuum, covering the surface of the microchannel structure with the suspension, and then leaving it to stand or applying external force, so that the fluorescent material particles settle into the microchannel; S5, repeat filling: detect whether the fluorescent material particles in the microchannel are filled to the target thickness, if not, repeat the S4 step, if yes, proceed to the next step; S6. Post-processing: cleaning the surface of the microchannel structure and packaging it to obtain an X-ray fluorescent screen.

2. The method for preparing an X-ray fluorescent screen according to claim 1, characterized in that: In the step S1, an organic solvent and water are used for cleaning, and the organic solvent is anhydrous ethanol or acetone; the microchannel structure is ultrasonically cleaned for 5-15 minutes.

3. The method for preparing an X-ray fluorescent screen according to claim 1, characterized in that: In the step S2, the coating is performed by evaporation, sputtering or atomic layer deposition; the reflective film is made of aluminum or silver.

4. The method for preparing an X-ray fluorescent screen according to claim 3, characterized in that: In the step S2, a protective film is plated on the surface of the reflective film, the protective film is made of silicon dioxide or aluminum oxide, and the thickness of the protective film is 20-150 nm.

5. The method for preparing an X-ray fluorescent screen according to claim 1, characterized in that: In the step S3, the fluorescent material particles are gadolinium oxysulfide or cesium iodide, and the average particle size of the fluorescent material particles is 0.1-10 μm.

6. The method for preparing an X-ray fluorescent screen according to claim 1, characterized in that: In the step S3, the volume ratio between the surfactant and the carrier solvent is 1:(50-200).

7. The method for preparing an X-ray fluorescent screen according to claim 1, characterized in that: In the step S3, the surfactant is DMF or DMSO or N-methylpyrrolidone; the carrier solvent is anhydrous ethanol or isopropanol or acetone.

8. The method for preparing an X-ray fluorescent screen according to claim 1, characterized in that: In the step S4, the external force applied is vibration or centrifugation of the microchannel structure; there is a height difference between the liquid surface of the suspension and the surface of the microchannel structure, and the height difference is 2-20 cm.

9. The method for preparing an X-ray fluorescent screen according to claim 1, characterized in that: In the step S6, the fluorescent material particles remaining on the surface of the microchannel structure are removed, and then an organic film layer is coated on the surface of the microchannel structure, and the organic film layer is a polyester film layer, a polyethylene film layer, a polypropylene film layer or a polyether film layer.

10. An X-ray fluorescent screen, characterized in that: The X-ray fluorescent screen is manufactured by the method for manufacturing an X-ray fluorescent screen according to any one of claims 1 to 9; the X-ray fluorescent screen comprises a microchannel structure, the microchannel structure is provided with a plurality of microchannels that are connected and arranged in an array, and the microchannels are filled with X-ray fluorescent material particles.

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