Large-area scintillation crystal array and preparation method thereof

Abstract

The invention discloses a large-area scintillation crystal array and a preparation method thereof. The array is assembled by adopting a plurality of slotted small crystal blocks, the plane precision of the array is ensured by adopting a gasket during assembly, a wafer is positioned by adopting a splicing clamp so as to ensure the geometric dimension precision, and the splicing efficiency is remarkably improved by adopting UV glue for bonding. Compared with a method for manufacturing the array by using a large-area crystal block, the method not only reduces the requirements on the crystal quality and the growth size, but also effectively utilizes the redundant material of the crystal, and realizes the maximum utilization of resources. And meanwhile, compared with an array assembled by adopting a single crystal strip, the array assembling efficiency is remarkably improved, the manufacturing period is short, the efficiency is high, the product delivery speed is increased, and the good application prospect is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of crystal material processing, and in particular to a large-area scintillation crystal array and a preparation method thereof. Background Art

[0002] Scintillators are special functional materials that can emit photons when exposed to high-energy rays. This property makes them have wide application potential in many high-tech fields. When high-energy rays, such as X-rays or gamma rays, are incident on scintillator crystals, they interact with atoms inside the crystals, causing electrons to jump from low-energy states to high-energy states. Subsequently, when these electrons return to low-energy states, they release photons, generating so-called scintillation light. This scintillation light can be captured by detectors and converted into electrical signals, thereby realizing the detection of high-energy rays.

[0003] Titanium oxide (TiO 2 ) As a high-quality reflective layer material, it is widely used in the production of scintillation crystal arrays due to its high light reflection efficiency. Especially in the manufacture of large-area scintillation crystal arrays, the titanium oxide reflective layer can significantly improve the light reflection efficiency of the scintillation array and enhance the performance of the detector. Therefore, titanium oxide plays a vital role in the production of reflective layers for large-area scintillation crystal arrays.

[0004] Large-area titanium oxide scintillating crystal arrays have shown great application prospects in many high-tech fields. In the field of nuclear medicine, it can be used to manufacture high-resolution X-ray or gamma-ray detectors, improve the clarity and accuracy of medical images, and provide strong support for the diagnosis and treatment of diseases. In the field of security inspection, it can be used to detect hidden radioactive substances or nuclear materials, and enhance the ability to ensure national security and public security. In addition, in the field of high-energy physics and cosmic ray detectors, large-area titanium oxide scintillating arrays also play an irreplaceable role.

[0005] However, the manufacturing technology of large-area titanium oxide scintillating crystal arrays faces many challenges. There are two main traditional methods for manufacturing large-area titanium oxide arrays: Method 1: Select a scintillator crystal rod, cut the crystal rod into crystal segments, cut the resulting crystal segments into large-area wafers, and then groove, glue, grind, and polish the large-area wafers. This method requires the size of the large-area wafer to be large enough, close to or exceeding the growth size of the crystal (Φ about 60mm), and it is difficult to find crystal materials, with many bottlenecks and low material utilization. In addition, the large-area wafer needs to be free of internal cracks, clouds and other defects, and has high requirements for the quality of the crystal, further reducing the material utilization.

[0006] Method 2: Select a scintillator crystal rod, cut it into crystal segments, then cut the resulting crystal segments into crystal bars, and finally assemble the crystal bars into an array, then fill the array with glue, grind, and polish it. In this method, the assembly operation of a single crystal bar is complicated, and it is difficult to ensure the geometric dimensional accuracy, which affects the overall performance of the array; and the assembly process of a single crystal bar is long and inefficient, which is not conducive to large-scale industrial production.

[0007] In view of the wide application prospects of large-area titanium oxide scintillating crystal arrays and the problems existing in traditional manufacturing methods, it is particularly important to study low-cost, industrializable large-area titanium oxide array processing technology. This will not only help promote the development of related high-tech fields, but also provide stronger technical guarantees for national security and public safety. Summary of the invention

[0008] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a large-area scintillation crystal array and a method for preparing the same, so as to solve the problems of low material utilization, long process flow, low efficiency and difficulty in ensuring geometric dimensional accuracy in the prior art of preparing scintillation crystal arrays.

[0009] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows: A method for preparing a large-area scintillation crystal array comprises the following steps: (1) After processing the scintillator crystal rod into a number of scintillator wafers of uniform size, the wafers are slotted, and the slots formed after the slotting divide the wafers into a number of uniformly arranged rectangular blocks; (2) cleaning the wafer obtained in step (1) and setting it aside; (3) preparing a splicing fixture according to the scintillation crystal array to be prepared and setting it aside; the splicing fixture comprises a plurality of mutually perpendicular partitions, and the thickness of the partitions corresponds to the width of the slots; (4) Take a rectangular gasket and place it horizontally on a workbench, evenly apply a layer of adhesive on the upper surface of the rectangular gasket, and then place the splicing fixture obtained in step (3) horizontally on the rectangular gasket, so that all partitions divide the surface of the rectangular gasket into a number of equal rectangular areas, and the length and width of the chip obtained in step (2) correspond to the rectangular areas; (5) evenly placing the wafer obtained in step (2) on the rectangular gasket obtained in step (4), and making sure that the wafer completely covers the rectangular gasket; (6) removing the splicing fixture from the product obtained in step (5), and then cleaning and drying the product obtained in step (5); sleeve a "mouth"-shaped baffle plate on the outside of the dried product, wherein the height of the baffle plate is greater than the sum of the thickness of the wafer and the thickness of the gasket; and then pouring reflective glue into the gap formed between the notch on the product and the splicing fixture after the splicing fixture is removed, until the reflective glue fills the space inside the "mouth"-shaped baffle plate; (7) After the reflective adhesive is solidified, the product in the “mouth”-shaped baffle is taken out, and the surface of the obtained product is ground and polished to obtain a scintillation crystal array.

[0010] Furthermore, in step (1), the specific steps of processing the scintillator crystal rod into the scintillator wafer are: firstly, the scintillator crystal rod is segmented to obtain scintillator crystal segments, and then the obtained crystal segments are cut into a plurality of wafers of uniform size by wire cutting or inner circle cutting.

[0011] Furthermore, in the step (1), the wafer is cleaned before grooving the wafer.

[0012] Furthermore, the adhesive in step (4) is UV adhesive.

[0013] Furthermore, after the wafer is placed in step (5), ultraviolet light is used to irradiate the UV glue to accelerate its curing rate.

[0014] Furthermore, the reflective adhesive in step (6) comprises titanium dioxide and epoxy resin.

[0015] Furthermore, the size of the wafer is a rectangle with a length of 10-50 mm and a width of 10-50 mm.

[0016] Furthermore, the cleaning process in step (6) is to sequentially perform ultrasonic cleaning, alcohol cleaning, and deionized water or distilled water rinsing on the obtained product.

[0017] Furthermore, the drying method in step (6) is nitrogen drying, vacuum drying or hot air drying.

[0018] A large-area scintillation crystal array is prepared by adopting the method.

[0019] Compared with the prior art, the present invention has the following beneficial effects: 1. The preparation method of the large-area scintillation crystal array provided by the present invention uses a number of slotted small crystal blocks to assemble into an array. Compared with using a large-area crystal block to make an array, this method not only reduces the requirements for crystal quality and growth size, but also effectively utilizes the excess crystal material, thereby maximizing the utilization of resources. At the same time, compared with the use of a single crystal bar to assemble the array, the present invention significantly improves the array assembly efficiency, has a short production cycle, high efficiency, and improves the product delivery speed; and compared with the assembly of a single crystal bar, the assembled array crystals of the present invention have higher pixel consistency, better array luminescence consistency, more convenient coupling for back-end electronic components, and better production effect. In addition, when assembling the array, the present invention uses a high-precision splicing fixture for positioning, with good verticality, ensuring the geometric size accuracy of the array, and using UV glue for bonding. Based on the advantages of fast and convenient curing of UV glue, this splicing method is very efficient, has low requirements on employee operating skills, is highly reproducible, and the assembly time of a single product is within 10 minutes.

[0020] 2. The present invention is no longer limited to the original growth size of the crystal in processing the array size. The number of crystal blocks can be increased or decreased according to the array size requirements to obtain scintillation crystal arrays of different sizes, which has the advantages of strong adaptability, high compatibility and strong scalability. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a design drawing of a large-area scintillation crystal array in an embodiment of the present invention; Figure 2 This is a schematic diagram of the assembly structure of the scintillation crystal array of the present invention; Figure 3 This is a schematic diagram of the product structure of the scintillation crystal array before potting of the present invention.

[0022] In the figure, there are gasket 1, chip 2, and splicing fixture 3. DETAILED DESCRIPTION

[0023] The specific implementation modes of the present invention are further described in detail below in conjunction with specific examples. Example

[0024] See also Figure 1~Figure 3 , a method for preparing a large-area scintillation crystal array, comprising the following steps: (1) After processing the scintillator crystal rod into a plurality of scintillator wafers 2 of uniform size, the wafers 2 are slotted, and the slots formed after the slotting divide the wafer 2 into a plurality of uniformly arranged rectangular blocks; In specific implementation, the specific steps of processing the scintillator crystal rod into the scintillator chip 2 are: first cut the scintillator crystal rod into segments to obtain scintillator crystal segments, and then use wire cutting or inner circle cutting technology to cut the obtained crystal segments into several chips 2 of uniform size. The crystal rod is cut into segments before slicing. First, because the crystal rod is very large, it is more operable to slice the chips after cutting; second, because there may be quality problems in the middle of the scintillator crystal material, if the crystal rod is sliced ​​directly, because the crystal rod is too long, it can generally only be sliced ​​along the diameter direction of the crystal rod, and it is difficult to avoid crystal materials with quality problems, which will cause quality problems in the subsequent crystal array. Slicing the crystal rod directly requires higher quality of the crystal rod, so it is cut into segments first and then sliced. In addition, high-precision wire cutting or inner circle cutting can minimize material waste while ensuring cutting accuracy and surface quality.

[0025] In specific implementation, before grooving the wafer 2, the wafer 2 needs to be cleaned to remove surface residues and contaminants to ensure smooth grooving and grooving quality.

[0026] In the specific implementation, laser grooving technology or mechanical scribing technology can be used for grooving. Laser grooving technology is particularly common in high-end semiconductor manufacturing due to its high precision, high efficiency and non-contact characteristics. It uses the high energy density of the laser beam to quickly form a notch on the surface of the wafer 2, while avoiding damage to the internal structure of the wafer 2. Mechanical scribing uses a precision mechanical tool to carve a notch inside the wafer 2, which is suitable for scenes with specific requirements for the shape and size of the notch. Compared with mechanical scribing and grooving, laser grooving has a faster cutting speed. For different materials, the process parameters of different groove depths and laser powers require a lot of time to debug. Otherwise, it is very easy to cause the verticality of the incision to be poor and "V"-shaped, resulting in uneven thickness of the reflective layer of the subsequent product and poor luminescence of the product. Therefore, mechanical scribing and grooving are generally selected. After the grooving is completed, the wafer 2 needs to be strictly inspected and tested to ensure that the size, shape and position accuracy of the notch meet the design requirements, and at the same time check whether the wafer 2 has additional damage or defects due to the grooving process. Wafers 2 that do not meet the standards need to be reworked or scrapped to ensure the quality and reliability of the final product.

[0027] (2) cleaning the wafer 2 obtained in step (1) and setting it aside; After the wafer 2 is processed in the early stage such as slotting, tiny particles, grease, metal ions and other pollutants often remain on the surface. If these pollutants are not completely removed, they will have a serious impact on the subsequent production process, including reducing the optical performance of the wafer 2. Therefore, it is particularly important to thoroughly and effectively clean the slotted wafer 2. In specific implementation, in the cleaning process of the wafer 2, hydrofluoric acid is usually used to remove the natural oxide layer and other inorganic pollutants on the surface of the scintillation crystal, providing a cleaner and easier to handle surface for the subsequent cleaning steps, and then using the solubility of gasoline to separate organic matter from the crystal surface and dissolve it in gasoline, remove grease, oil stains and other organic pollutants on the crystal surface, and finally use the solubility and volatility of alcohol to further remove residual oil stains and impurities on the surface, ensuring that the crystal surface after cleaning is cleaner and drier. During cleaning, the slotted wafer 2 is generally immersed in a cleaning agent, or the cleaning agent is evenly sprayed on the surface of the wafer 2 using a spray. Subsequently, the cleaning agent is fully mixed and removed with the pollutants on the surface of the wafer 2 by mechanical stirring, ultrasonic vibration or high-pressure washing. During this process, the cleaning time and temperature need to be strictly controlled to ensure that the cleaning agent can fully exert its effect while avoiding damage to the wafer 2 itself. After cleaning, the wafer 2 needs to be thoroughly rinsed and dried to remove residual cleaning agent. Deionized water or distilled water is usually used for rinsing to ensure that no new contaminants are introduced. Drying can be done by nitrogen blowing, vacuum drying or hot air drying to avoid contamination or damage to the wafer 2 during the drying process.

[0028] (3) preparing a splicing fixture according to the scintillation crystal array to be prepared and setting it aside; the splicing fixture comprises a plurality of mutually perpendicular partitions, and the thickness of the partitions corresponds to the width of the slots; In specific implementation, the splicing fixture 3 is made by 3D printing technology. The fixture prepared in this way has high precision, and can make the geometric size of the prepared array have high precision.

[0029] In a specific implementation, the splicing fixture 3 can be in a cross shape or a tic-tac-toe shape.

[0030] (4) Take a rectangular gasket 1 and place it horizontally on a workbench, evenly apply a layer of adhesive on the upper surface of the rectangular gasket 1, and then place the splicing fixture 3 obtained in step (3) horizontally on the rectangular gasket 1, so that all partitions divide the surface of the rectangular gasket 1 into a number of equal rectangular areas, and the length and width of the wafer 2 obtained in step (2) correspond to the rectangular areas; In a specific implementation, the adhesive is UV adhesive. UV adhesive has the advantages of fast curing, high strength, and low volatility. After the subsequent wafer 2 is fixed, the UV adhesive can be irradiated with ultraviolet light to accelerate the curing rate of the adhesive, thereby effectively shortening the preparation time of the array. In addition to fixing the relative position of each crystal block, the UV adhesive can also realize the recovery and re-splicing of semi-finished crystal blocks with unqualified sizes after splicing.

[0031] In specific implementation, the rectangular gasket 1 is a rectangular glass gasket 1. These gaskets 1 play a key supporting and positioning role in the assembly process, ensuring the accuracy of the array plane. In addition, the glass gasket 1 is easy to obtain and cheap, which is convenient for promotion and application.

[0032] (5) evenly placing the wafer 2 obtained in step (2) on the rectangular gasket 1 obtained in step (4), and making the wafer 2 just completely cover the rectangular gasket 1; (6) Taking out the splicing fixture 3 from the product obtained in step (5), then cleaning and drying the product obtained in step (5), and sleeve a "mouth"-shaped baffle plate on the outer side of the dried product, wherein the height of the baffle plate is greater than the sum of the thickness of the wafer and the thickness of the gasket; then pouring reflective glue into the gap formed between the notch on the product and the splicing fixture 3 after taking out, until the reflective glue fills the space inside the "mouth"-shaped baffle plate; In specific implementation, if the material of the fixture allows, the fixture can also be dissolved by heating to facilitate removal. However, it should be noted that the melting temperature of the fixture needs to be lower than the softening temperature of the UV glue to avoid damaging the cured UV glue layer during the heating process.

[0033] In specific implementation, the cleaning process in step (6) is to sequentially perform ultrasonic cleaning, alcohol cleaning, and deionized water or distilled water rinsing on the obtained product. The main purpose of cleaning the product obtained in step (5) is to remove dust, particles, grease, organic residues and other pollutants that may be introduced during the splicing process, ensure the cleanliness of the array surface, and thus ensure the stability of subsequent processes and the reliability of the product. Ultrasonic cleaning uses the cavitation effect and microjet effect generated by high-frequency sound waves in the cleaning liquid, which can penetrate into the gaps and grooves on the array surface and effectively peel off and remove pollutants attached to the product. This method not only has high cleaning efficiency, but also can avoid physical damage to the array itself. At the same time, alcohol cleaning is also an indispensable part of array cleaning. Alcohol, as an excellent organic solvent, has good solubility and volatility, and can quickly dissolve and remove dust and other organic pollutants on the array surface. On the basis of ultrasonic cleaning, further cleaning with alcohol can ensure that the array surface is thoroughly clean. When performing ultrasonic and alcohol cleaning, it is necessary to strictly control the concentration, temperature, cleaning time and frequency of the cleaning liquid to ensure the optimization of the cleaning effect. After cleaning, the array needs to be thoroughly rinsed and dried. Deionized or distilled water is usually used for rinsing to ensure that all residual cleaning fluid and contaminants are removed. Drying can be done by nitrogen drying, vacuum drying, or hot air drying to avoid new contamination or damage during the drying process.

[0034] In a specific implementation, the reflective adhesive in step (6) includes titanium dioxide and epoxy resin.

[0035] (7) After the reflective adhesive is solidified, the product in the “mouth”-shaped baffle is taken out, and the surface of the obtained product is ground and polished to obtain a scintillation crystal array.

[0036] In specific implementation, the grinding in step (7) is to first grind the reflective adhesive layer to make the reflective adhesive layer reach the designed thickness, then grind the bottom of the product (light-emitting surface) to remove the rectangular gasket and excess crystals, while ensuring that the reflective adhesive in the notch at the bottom of the crystal can be exposed, and finally further grind the light-emitting surface to remove the tiny scratches and unevenness on the surface of the light-emitting surface. Since the adhesive layer after glue filling often exceeds the size requirements of the final product, it is necessary to use a precise grinding process to remove the excess adhesive layer material while ensuring the surface flatness, smoothness and reflective performance of the reflective adhesive layer. In this process, grinding tools such as diamond grinding wheels and polishing pads, as well as corresponding grinding fluids or coolants, are used to ensure grinding efficiency and grinding quality. The array light-emitting surface is the key part of the optical component responsible for light output or reception, and its surface quality directly affects the light transmission efficiency and optical performance. Therefore, in the process of grinding and polishing, it is necessary to use more sophisticated grinding materials and polishing processes, such as using polishing pads, polishing liquids, etc., to gradually reduce the particle size of the grinding particles and increase the polishing time, and gradually remove the tiny scratches and unevenness on the surface of the array light-emitting surface until extremely high surface finish and optical performance requirements are achieved. In the process of grinding and polishing, it is also necessary to strictly control processing parameters such as grinding pressure, grinding speed, polishing time, etc., to avoid excessive damage or deformation to the array light-emitting surface. At the same time, it is also necessary to strictly inspect and measure the surface after grinding and polishing, including surface roughness, flatness, optical properties, etc., to ensure that the quality and performance of the final product meet the design requirements.

[0037] In this embodiment, the obtained array is formed by splicing four chips 2 with a size of 28.5mm × 28.5mm. The size of the obtained array before glue filling is 57.2mm × 57.2mm, the size of the rectangular block is 2.67mm × 2.67mm, the groove width between two adjacent rectangular blocks is 0.2mm, and the size of the glass spacer 1 is 57.2mm × 57.2mm; after glue filling, grinding and polishing, the size of the array is 57.6mm × 57.6mm.

[0038] In specific implementation, the processing of the array size is no longer limited to the original growth size of the crystal. The number of crystal blocks can be increased or decreased according to the array size requirements to obtain scintillation crystal arrays of different sizes.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the technical solution. Those skilled in the art should understand that those modifications or equivalent substitutions of the technical solution of the present invention that do not depart from the purpose and scope of the technical solution should be included in the scope of the claims of the present invention.

Claims

1. A method for preparing a large-area scintillation crystal array, characterized in that: The following steps are involved: (1) After processing the scintillator crystal rod into a number of scintillator wafers of uniform size, the wafers are slotted, and the slots formed after the slotting divide the wafers into a number of evenly arranged rectangular blocks; (2) cleaning the wafer obtained in step (1) and setting it aside; (3) preparing a splicing fixture according to the scintillation crystal array to be prepared and setting it aside; the splicing fixture comprises a plurality of mutually perpendicular partitions, and the thickness of the partitions corresponds to the width of the slots; (4) Take a rectangular gasket and place it horizontally on a workbench, evenly apply a layer of adhesive on the upper surface of the rectangular gasket, and then place the splicing fixture obtained in step (3) horizontally on the rectangular gasket, so that all partitions divide the surface of the rectangular gasket into a number of equal rectangular areas, and the length and width of the chip obtained in step (2) correspond to the rectangular areas; (5) evenly placing the wafer obtained in step (2) on the rectangular gasket obtained in step (4), and making sure that the wafer completely covers the rectangular gasket; (6) removing the splicing fixture from the product obtained in step (5), and then cleaning and drying the product obtained in step (5); sleeve a "mouth"-shaped baffle plate on the outside of the dried product, wherein the height of the baffle plate is greater than the sum of the thickness of the wafer and the thickness of the gasket; and then pouring reflective glue into the gap formed between the notch on the product and the splicing fixture after removal, until the reflective glue fills the space inside the "mouth"-shaped baffle plate; (7) After the reflective adhesive is solidified, the product in the "mouth"-shaped baffle is taken out, and the surface of the obtained product is ground and polished to obtain a scintillation crystal array.

2. The method for preparing a large-area scintillation crystal array according to claim 1, characterized in that: In the step (1), the specific steps of processing the scintillator crystal rod into the scintillator wafer are: firstly, the scintillator crystal rod is segmented to obtain scintillator crystal segments, and then the obtained crystal segments are cut into a plurality of wafers of uniform size by wire cutting or inner circle cutting.

3. The method for preparing a large-area scintillation crystal array according to claim 1, characterized in that: In the step (1), the wafer is cleaned before grooving the wafer.

4. The method for preparing a large-area scintillation crystal array according to claim 1, characterized in that: The adhesive in step (4) is UV adhesive.

5. The method for preparing a large-area scintillation crystal array according to claim 4, characterized in that: After the wafer is placed in step (5), ultraviolet light is used to irradiate the UV glue to accelerate its curing rate.

6. The method for preparing a large-area scintillation crystal array according to claim 1, characterized in that: The reflective adhesive in step (6) comprises titanium dioxide and epoxy resin.

7. The method for preparing a large-area scintillation crystal array according to claim 1, characterized in that: The size of the wafer is a rectangle with a length of 10-50 mm and a width of 10-50 mm.

8. The method for preparing a large-area scintillation crystal array according to claim 1, characterized in that: The cleaning process in step (6) is to sequentially perform ultrasonic cleaning, alcohol cleaning, and deionized water or distilled water rinsing on the obtained product.

9. The method for preparing a large-area scintillation crystal array according to claim 1, characterized in that: The drying method in step (6) is nitrogen drying, vacuum drying or hot air drying.

10. A large-area scintillation crystal array, characterized in that: The method is prepared by any one of claims 1 to 9.

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