阅读说明：本技术 一种塑料闪烁体薄片、制备方法及其制备装置 (Plastic scintillator sheet, preparation method and preparation device thereof ) 是由 潘子文 王齐 魏伟 于 2020-12-29 设计创作，主要内容包括：本发明提供一种塑料闪烁体薄片,该塑料闪烁体薄片由基体材料、发光剂和移波剂组成,该制备方法包括以下步骤S1制备装置组装和清洗,S2制备装置测试,S3净化制备装置,S4闪烁体溶液制备,S5闪烁体溶液反应准备,S6闪烁体溶液聚合反应和S7闪烁体薄片去应力；该制备装置包括可拆卸的反应釜,该反应釜包括边框、下盖板和上盖板,内设置有成模板,成模板之间设置有成型腔用于成型塑料闪烁体薄片。该制备方法使用聚合工艺,根据需要制备成大尺寸的塑料闪烁体薄片,厚度相对偏差小,对塑料闪烁体基体、发光剂和移波剂充分均匀混合和反应,保证塑料闪烁体薄片在不同位置对射线的高探测效率和一致性。(The invention provides a plastic scintillator sheet, which consists of a base material, a luminescent agent and a wave-shifting agent, and the preparation method comprises the following steps of S1 assembly and cleaning of a preparation device, S2 preparation device testing, S3 purification preparation device, S4 scintillator solution preparation, S5 scintillator solution reaction preparation, S6 scintillator solution polymerization reaction and S7 scintillator sheet destressing; the preparation device comprises a detachable reaction kettle, wherein the reaction kettle comprises a frame, a lower cover plate and an upper cover plate, a molding plate is arranged in the reaction kettle, and a molding cavity is arranged between the molding plates and used for molding the plastic scintillator sheet. The preparation method uses a polymerization process, prepares the large-size plastic scintillator sheet according to the needs, has small relative deviation of thickness, fully and uniformly mixes and reacts the plastic scintillator matrix, the luminescent agent and the wave shifting agent, and ensures high detection efficiency and consistency of the plastic scintillator sheet on rays at different positions.)

1. A plastic scintillator sheet, characterized by: the plastic scintillator sheet consists of a base material, a luminescent agent and a wave-shifting agent, wherein the luminescent agent accounts for 3-7 percent (by weight percentage), and the wave-shifting agent accounts for 0.3-0.8 percent (by weight percentage).

2. The plastic scintillator sheet of claim 1, wherein: the base material is formed by polymerizing plastic-based monomers, wherein the plastic-based monomers are selected from one monomer or a monomer mixture of styrene, alpha-methyl styrene, 4-methyl styrene, vinyl toluene and methyl methacrylate.

3. The plastic scintillator sheet of claim 1, wherein: the luminescent agent is selected from one or a mixture of p-terphenyl, 2, 5-diphenyl oxazole, 2- (4 '-tert-butylphenyl) -5- (4' -biphenyl) -1,3, 4-oxadiazole and 2- (4-biphenyl) -5-phenyl oxadiazole.

4. The plastic scintillator sheet of claim 1, wherein: the wave transfer agent is selected from one or a mixture of 1, 4-bis (5-phenyloxazole) benzene POPOPOPOP, 1, 4-bis (5-phenyl-2-oxazolyl) benzene, 1, 4-bis (2-methyl styryl) benzene, 1, 4-bis (4-methyl styryl) benzene and 9, 10-diphenyl anthracene.

5. The manufacturing apparatus of a plastic scintillator sheet as claimed in claim 1, wherein: the preparation device comprises a reaction kettle (1) and is detachable, wherein the reaction kettle (1) comprises a frame (11), a lower cover plate (13) and an upper cover plate (14), the lower cover plate (13) and the upper cover plate (14) are covered on two sides of the frame (11), a template cavity (16) is formed among the frame (11), the lower cover plate (13) and the upper cover plate (14), a forming plate (2) is arranged in the template cavity (16), a forming cavity (24) is arranged between the forming plate (2), and the forming cavity (24) is used for forming the plastic scintillator thin sheet.

6. The manufacturing apparatus according to claim 5, wherein: frame (11) one end is provided with opening (111), install upper ledge (12) on opening (111), frame (11) with be provided with seal groove (151) on upper ledge (12), frame (11) with upper ledge (12) forms together outer frame (15) of reation kettle (1).

7. The manufacturing apparatus according to claim 6, wherein: the upper frame (12) is further provided with a condensation interface (121) and a nitrogen interface (122), the condensation interface (121) is used for introducing a plastic scintillator into the reaction kettle (1), and the nitrogen interface (122) is used for filling nitrogen into the reaction kettle (1) or extracting vacuum.

8. The manufacturing apparatus according to claim 5, wherein: the forming plate (2) is arranged in a lower middle area of the plate cavity (16), the plate cavity (16) is divided into a feeding cavity (3) and a balance cavity (4) by the forming plate (2), the feeding cavity (3) is positioned at the upper part of the plate cavity (16), and the balance cavity (4) is positioned at the lower part of the plate cavity (16).

9. The manufacturing apparatus according to claim 8, wherein: the material of the molding plate (2) is a stainless steel mirror surface clapboard, quartz glass or a mirror surface aluminum plate.

10. The method for preparing a plastic scintillator sheet according to claim 1, comprising the steps of:

s1 assembling and cleaning the preparation device, assembling the preparation device to form a reaction kettle, and cleaning the preparation device;

s2 testing a preparation device, and carrying out pressure-resistant airtight testing on the preparation device;

s3 purifying the preparation device, loading the preparation device into a heating furnace, and introducing nitrogen into the preparation device to replace the air in the preparation device and the reaction kettle, so that a nitrogen environment is formed in the reaction kettle;

s4 scintillator solution preparation, namely adding a luminescent agent and a wave-shifting agent into the base material to form scintillator solution, and vacuumizing and shaking to uniformly mix the scintillator solution;

s5 scintillator solution reaction preparation, namely introducing the scintillator solution prepared in the step S4 into the reaction kettle of the preparation device in the step S3, forming sheet liquid between the molding plates of the reaction kettle by the scintillator solution, and continuously introducing nitrogen to stir the scintillator solution; simultaneously starting a heating furnace to preheat the preparation device and the reaction kettle;

s6 scintillator solution polymerization reaction, after preheating, adjusting a heating furnace to heat to 120-130 ℃ at a constant speed, fully performing polymerization reaction on the sheet liquid formed between the molding plates, and curing to form a scintillator sheet;

s7, destressing the scintillator sheet, adjusting the heating furnace to slowly cool to 20-25 ℃ at a constant speed after solidification to obtain a plastic scintillator sheet;

and S8, post-processing, namely taking out the preparation device and the reaction kettle from the heating furnace, disassembling the preparation device and the reaction kettle, and taking out the plastic scintillator sheets between the templates layer by layer.

Technical Field

The invention relates to the technical field of nuclear radiation detection material preparation, in particular to a plastic scintillator sheet, a preparation method of the sheet and a preparation device of the sheet.

Background

In nuclear detection technology, a plastic scintillator is an important member of scintillators, and plays an important role in measuring charged particles, neutrons and other ray particles. When particles or rays enter the plastic scintillator and are absorbed by the plastic matrix, the generated electron and hole pairs excite the first luminescent substance and generate luminescence, but the luminescence wavelength is in the ultraviolet region and is easy to be absorbed by the plastic matrix and can not be emitted, so the second luminescent substance, also called a wave shifting agent, is often adopted to convert the ultraviolet light emitted by the first luminescent substance into visible light so as to be easy to be emitted from the matrix.

Plastic scintillators are designed into various special geometric shapes for manufacturing radiation detectors of alpha, beta and gamma rays due to their high detection efficiency and excellent plasticity for alpha, beta and gamma rays. For the measured object with large area and special geometric shape, the large area plastic scintillator corresponding to the measured object needs to be processed. However, the thickness of the large-area plastic scintillator is only 0.5-1 mm, the large-area plastic scintillator is not easy to process, and the large-area plastic scintillator is extremely low in rigidity and easy to scratch and break.

At present, the mainstream preparation process of the plastic scintillator sheet is an extrusion process. The raw materials of the process are melted to a molten state at high temperature, and then are extruded into a plastic scintillator sheet by an extruder through a fixed grinding tool. But have a small size and poor thickness uniformity; the plastic scintillator sheet produced by the extrusion process is small in size due to the limitation of the size of a die. The detection efficiency consistency is poor; because the doping amount of the luminescent agent and the wave shifting agent is small, the luminescent agent and the wave shifting agent are difficult to be fully and uniformly mixed with the styrene particles, and the consistency of the detection efficiency of radioactive rays at different positions on the extruded plastic scintillator sheet is poor. Accordingly, the present invention provides a plastic scintillator sheet, a method for manufacturing the plastic scintillator sheet, and a manufacturing apparatus for the manufacturing method.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a plastic scintillator sheet which can be prepared into a large-size plastic scintillator sheet according to requirements, the relative deviation of the thickness is less than 3 percent, and the size reaches 1000 multiplied by 500mm²(ii) a The preparation method uses a polymerization process to fully and uniformly mix and react the plastic scintillator matrix, the luminescent agent and the wave shifting agent, and ensures high detection efficiency and consistency of the plastic scintillator sheet to rays at different positions.

In order to achieve the purpose, the invention provides a plastic scintillator sheet, which consists of a base material, a luminescent agent and a wave-shifting agent, wherein the luminescent agent accounts for 3-7% (weight percentage content), and the wave-shifting agent accounts for 0.3-0.8% (weight percentage content).

The base material is formed by polymerizing a plastic-based monomer, wherein the plastic-based monomer is one monomer or a monomer mixture of styrene, alpha-methyl styrene, 4-methyl styrene, vinyl toluene and methyl methacrylate;

the luminescent agent is selected from one or a mixture of p-terphenyl, 2, 5-diphenyl oxazole, 2- (4 '-tert-butylphenyl) -5- (4' -biphenyl) -1,3, 4-oxadiazole and 2- (4-biphenyl) -5-phenyl oxadiazole;

the wave transfer agent is selected from one or a mixture of 1, 4-bis (5-phenyloxazole) benzene POPOPOPOP, 1, 4-bis (5-phenyl-2-oxazolyl) benzene, 1, 4-bis (2-methyl styryl) benzene, 1, 4-bis (4-methyl styryl) benzene and 9, 10-diphenyl anthracene.

Furthermore, the monomer of the plastic-based monomer is pure new monomer obtained by fractionating monomer raw materials with the purity of more than 99.5 percent.

Further, the plastic scintillator sheet is obtained by respectively adding the luminescent agent and the wave-shifting agent into the plastic-based monomer, uniformly mixing under a vacuum condition, pouring into a reaction kettle in a nitrogen environment, and carrying out polymerization reaction under the conditions of heating and stirring. Through polymerization reaction, the plastic-based monomer, the luminescent agent and the wave shifting agent of the plastic scintillator sheet can be fully and uniformly mixed, and the high detection efficiency and consistency of the plastic scintillator sheet to radioactive rays at different positions are ensured; meanwhile, the microstructure of the base material of the plastic scintillator sheet formed by the polymerization process is not affected, and the luminous yield of the produced plastic scintillator sheet is higher than that of a product produced by the conventional extrusion process by 40-70%.

In order to achieve the above purpose, the present invention further provides a matched preparation apparatus for preparing the plastic scintillator sheet, the preparation apparatus includes a reaction kettle 1, the reaction kettle 1 is detachable, and includes a frame 11, a lower cover plate 13 and an upper cover plate 14, the lower cover plate 13 and the upper cover plate 14 are covered on two sides of the frame 11, a mold plate cavity 16 is formed between the frame 11, the lower cover plate 13 and the upper cover plate 14, a mold forming plate 2 is arranged in the mold plate cavity 16, the mold forming plate 2 includes a first mold plate 21 and a second mold plate 22, a molding cavity 24 is arranged between the first mold plate 21 and the second mold plate 22, and the molding cavity 24 is used for molding the plastic scintillator sheet.

Further, an opening 111 is formed in one end of the frame 11, an upper frame 12 is installed on the opening 111, a sealing groove 151 is formed in the frame 11 and the upper frame 12, and the frame 11 and the upper frame 12 together form the outer frame 15 of the reaction kettle 1.

The upper frame 12 is further provided with a condensation interface 121 and a nitrogen interface 122, the condensation interface 121 is used for introducing a plastic scintillator into the reaction kettle 1, and the nitrogen interface 122 is used for filling nitrogen into the reaction kettle 1 or extracting vacuum.

Further, both sides of the outer frame 15 are respectively provided with a circle of sealing groove 151, a sealing ring is arranged in the sealing groove 151, and the lower cover plate 13 and the upper cover plate 14 are sealed by the sealing ring arranged in the sealing groove 151 of the reaction kettle 1.

Further, the template forming plate 2 is arranged in a lower middle area of the template cavity 16, the template forming plate 2 divides the template cavity 16 into a feeding cavity 3 and a balance cavity 4, the feeding cavity 3 is located at the upper part of the template cavity 16, and the balance cavity 4 is located at the lower part of the template cavity 16. According to the arrangement mode, the plastic scintillator or the nitrogen entering from the condensation interface and the nitrogen interface can be balanced and communicated in the template cavity, so that the template cavity is in a communicated state, the plastic scintillator or the nitrogen can be well filled, and the gas is completely pumped out when the vacuum is pumped.

Further, the material of the molding board 2 is a stainless steel mirror surface clapboard, quartz glass or a mirror surface aluminum plate; the spacers 23 are preferably sheets of feelers of different thickness. A partition plate 23 is arranged between the first template 21 and the second template 22 of the plurality of molding plates 2, and the partition plate 23 is used for controlling the thickness of the molding cavity 24; according to different thicknesses of the prepared plastic scintillator sheets, selecting partition plates with different thicknesses to be assembled between the forming templates; meanwhile, a plurality of finished templates can be arranged as required, the finished templates are gradually stacked together according to the arrangement mode of the first template and the second template, and the partition plates are arranged between the finished templates to control the thickness of the forming cavity, so that various plastic scintillator sheets with different thickness and sizes can be prepared.

In order to achieve the above object, the present invention also provides a preparation method of the plastic scintillator sheet, the preparation method comprising the steps of:

s1, assembling and cleaning the preparation device, and assembling the preparation device to form a reaction kettle; cleaning the preparation device according to the following sequence, cleaning with acetone solution → cleaning with purified water → cleaning with acetone solution → cleaning with purified water for three times, and then drying the preparation device with nitrogen;

s2 testing a preparation device, and carrying out pressure-resistant airtight testing on the preparation device, wherein the leakage rate of the airtight value is less than 0.15ml/min, and the pressure P value is more than or equal to 0.5MPa and less than or equal to 0.8 MPa;

s3, purifying the preparation device, loading the preparation device into a heating furnace, and introducing nitrogen into the preparation device to replace the air in the preparation device and the reaction kettle for 3-5 times of circulation so as to form a nitrogen environment in the reaction kettle;

s4 preparing a scintillator solution, namely adding the plastic-based monomer into a container capable of being vacuumized and shaken to be mixed, adding 3-7% of luminescent agent and 0.3-0.8% of wave-shifting agent into the plastic-based monomer to form the scintillator solution, vacuumizing and shaking for 25-35 min to uniformly mix the scintillator solution;

s5 scintillator solution reaction preparation, namely introducing the scintillator solution prepared in the step S4 into the reaction kettle of the preparation device in the step S3, enabling the scintillator solution to form sheet liquid between molding plates of the reaction kettle, continuously introducing nitrogen gas to stir the scintillator solution, and stirring for 3-5 hours; simultaneously starting a heating furnace to preheat the preparation device and the reaction kettle, wherein the preheating temperature is 60-70 ℃, and the preheating time is 5-10 hours;

s6 scintillator solution polymerization reaction, after preheating, adjusting the heating furnace to heat up to 120-130 ℃ at the speed of 4-5 ℃/h, and preserving heat for 130-140 h to ensure that the slice liquid formed between the molding plates is fully polymerized and solidified to form scintillator slices;

s7, destressing the scintillator sheet, and after solidification, adjusting the heating furnace to slowly cool to 20-25 ℃ at the speed of 4-5 ℃/h to obtain the plastic scintillator sheet;

and S8, post-processing, namely taking out the preparation device and the reaction kettle from the heating furnace, disassembling the preparation device and the reaction kettle, taking out the plastic scintillator sheets between the molding plates layer by layer, and detecting and confirming the plastic scintillator sheets.

Compared with the prior art, the invention has the following beneficial effects:

1. according to the plastic scintillator sheet, the scintillator solution forms a polymerization reaction in the reaction kettle of the preparation device and is solidified, so that the plastic scintillator matrix, the luminescent agent and the wave-shifting agent can be fully and uniformly mixed, and the consistency of the detection efficiency of the plastic scintillator sheet on radioactive rays at different positions is ensured.

2. The thickness uniformity of the plastic scintillator sheet prepared by the special reaction kettle formed by the preparation device is good, and the relative deviation of the thickness of the plastic scintillator sheet is less than 3 percent and is one order of magnitude lower than that of the existing extrusion process.

3. The invention has high luminous yield, the microstructure of the matrix material styrene of the plastic scintillator obtained by the polymerization process is basically not influenced, and the luminous yield of the produced plastic scintillator sheet is higher than that of the product produced by the existing extrusion process by 40-70 percent.

4. The size is adjustable and can produce products with large size, the process assembles the reaction kettle through the finished templates, the thickness between the finished templates is adjusted through the partition plate (clearance gauge), the minimum thickness reaches 0.25mm, plastic scintillator sheets with different thicknesses can be generated by polymerization in different thickness sizes according to requirements, the length and width of the products can reach 1000mm x 500mm, and the area reaches 5000cm²。

5. Compared with the secondary forming mode of the extrusion process, the plastic scintillator sheet produced by the polymerization process has no internal stress, does not generate bending deformation after long-term use, and has stable performance.

Drawings

FIG. 1 is an exploded view of the manufacturing apparatus;

FIG. 2 is a perspective view of the manufacturing apparatus;

FIG. 3 is a view showing an internal structure of the manufacturing apparatus;

FIG. 4 is a top block diagram of the manufacturing apparatus;

FIG. 5 is a sectional view of the production apparatus;

FIG. 6 is an enlarged sectional view of the production apparatus;

FIG. 7 is a photograph of a sample of the plastic scintillator sheet;

FIG. 8 is a sample thickness test chart of the plastic scintillator sheet;

fig. 9 is a sample wavelength test chart of the plastic scintillator sheet.

Reference numerals: 1-a reaction kettle, 11-a frame, 111-an opening, 12-an upper frame, 121-a condensation interface, 122-a nitrogen interface, 13-a lower cover plate, 14-an upper cover plate, 15-an outer frame, 151-a sealing groove and 16-a template cavity; 2-forming a template, 21-a first template, 22-a second template, 23-a partition plate and 24-a forming cavity; 3-a feeding cavity; 4-balance chamber.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples, so that those skilled in the art can fully understand the technical contents of the present invention. It should be noted that the specific embodiments described herein are only for explaining the present invention and are not used to limit the present invention.

The invention provides a plastic scintillator sheet, which consists of a base material, a luminescent agent and a wave-shifting agent, wherein the luminescent agent accounts for 3-7 percent (by weight percentage), and the wave-shifting agent accounts for 0.3-0.8 percent (by weight percentage). The base material is polymerized by plastic-based monomers, and the plastic-based monomers are selected from one monomer or a monomer mixture of styrene, alpha-methyl styrene, 4-methyl styrene, vinyl toluene and methyl methacrylate; the luminescent agent is one or a mixture of p-terphenyl, 2, 5-diphenyl oxazole, 2- (4 '-tert-butylphenyl) -5- (4' -biphenyl) -1,3, 4-oxadiazole and 2- (4-biphenyl) -5-phenyl oxadiazole; the wave transfer agent is one or a mixture of 1, 4-bis (5-phenyl oxazole) benzene POPOPOPOPOP, 1, 4-bis (5-phenyl-2-oxazolyl) benzene, 1, 4-bis (2-methyl styryl) benzene, 1, 4-bis (4-methyl styryl) benzene and 9, 10-diphenyl anthracene.

The preparation method for preparing the plastic scintillator sheet comprises the following steps:

s1, assembling and cleaning the preparation device, and assembling the preparation device to form a reaction kettle; cleaning the preparation device according to the following sequence, cleaning with an acetone solution → cleaning with purified water → cleaning with an acetone solution → cleaning with purified water for three times, and then drying the preparation device with nitrogen;

s2 testing the preparation device, and carrying out pressure-resistant airtight testing on the preparation device, wherein the leakage rate of an airtight value is less than 0.15ml/min, and the pressure P value is more than or equal to 0.5MPa and less than or equal to 0.8 MPa;

s3 purifying the preparation device, namely, loading the preparation device into a heating furnace, and introducing nitrogen into the preparation device for 3-5 times of circulation to replace the air in the preparation device and the reaction kettle, so that a nitrogen environment is formed in the reaction kettle;

s4 preparing a scintillator solution, namely adding a plastic-based monomer into a container capable of being vacuumized and shaken to be mixed, adding 3-7% of a luminescent agent and 0.3-0.8% of a wave-shifting agent into the plastic-based monomer to form the scintillator solution, vacuumizing and shaking for 25-35 min to uniformly mix the scintillator solution;

s5 scintillator solution reaction preparation, namely introducing the scintillator solution prepared in the step S4 into a reaction kettle of the preparation device in the step S3, enabling the scintillator solution to form sheet liquid between molding plates of the reaction kettle, and continuously introducing nitrogen to stir the scintillator solution for 3-5 hours; simultaneously starting a heating furnace to preheat the preparation device and the reaction kettle, wherein the preheating temperature is 60-70 ℃, and the preheating time is 5-10 hours;

s6 scintillator solution polymerization reaction, after preheating, adjusting the heating furnace to heat up to 120-130 ℃ at the speed of 4-5 ℃/h, and preserving heat for 130-140 h to ensure that the slice liquid formed between the molding plates is fully polymerized and solidified to form scintillator slices;

s7, destressing the scintillator sheet, and after solidification, adjusting the heating furnace to slowly cool to 20-25 ℃ at the speed of 4-5 ℃/h to obtain the plastic scintillator sheet;

and S8, post-processing, namely taking out the preparation device and the reaction kettle from the heating furnace, disassembling the preparation device and the reaction kettle, taking out the plastic scintillator sheets between the molding plates layer by layer, and detecting and confirming the plastic scintillator sheets. The test is shown in tables 1 to 3 with reference to FIG. 8, which shows the average thickness (mm) measured at multiple points.

As shown in fig. 1-3 and 5, the preparation device provided in the invention comprises a reaction kettle 1, wherein the reaction kettle 1 is detachable and comprises a frame 11, a lower cover plate 13 and an upper cover plate 14, the lower cover plate 13 and the upper cover plate 14 are covered on two sides of the frame 11, a template cavity 16 is formed between the frame 11, the lower cover plate 13 and the upper cover plate 14, a forming template 2 is arranged in the template cavity 16, the forming template 2 comprises a first template 21 and a second template 22, a forming cavity 24 is arranged between the first template 21 and the second template 22, and the forming cavity 24 is used for forming the plastic scintillator sheet. An opening 111 is formed at one end of the frame 11, an upper frame 12 is mounted on the opening 111, a sealing groove 151 is formed on the frame 11 and the upper frame 12, and the frame 11 and the upper frame 12 together form an outer frame 15 of the reaction kettle 1. The upper frame 12 is further provided with a condensation port 121 and a nitrogen port 122, the condensation port 121 is used for introducing the plastic scintillator into the reaction kettle 1, and the nitrogen port 122 is used for filling nitrogen into the reaction kettle 1 or extracting vacuum. The material of the molding board 2 is a stainless steel mirror surface clapboard, quartz glass or a mirror surface aluminum plate; the spacer 23 is preferably a thin sheet of feelers of different thickness. A partition plate 23 is arranged between the first template 21 and the second template 22 of the multiple molding plates 2, and the partition plate 23 is used for controlling the thickness of the molding cavity 24; according to different thicknesses of the prepared plastic scintillator sheets, selecting partition plates with different thicknesses to be assembled between the forming templates; meanwhile, a plurality of finished templates can be arranged as required, the finished templates are gradually stacked together according to the arrangement mode of the first template and the second template, and the partition plates are arranged between the finished templates to control the thickness of the forming cavity, so that various plastic scintillator sheets with different thickness and sizes can be prepared.

As a further improvement, as shown in fig. 5 and 6, a circle of sealing grooves 151 are respectively formed on both sides of the outer frame 15, sealing rings are disposed in the sealing grooves 151, and the lower cover plate 13 and the upper cover plate 14 seal the reaction vessel 1 by the sealing rings disposed in the sealing grooves 151.

As shown in fig. 2 and 5, the molding plate 2 is disposed in the lower middle region of the molding plate cavity 16, the molding plate 2 divides the molding plate cavity 16 into a feeding cavity 3 and a balancing cavity 4, the feeding cavity 3 is located at the upper part of the molding plate cavity 16, and the balancing cavity 4 is located at the lower part of the molding plate cavity 16. According to the arrangement mode, the plastic scintillator or the nitrogen entering from the condensation interface and the nitrogen interface can be balanced and communicated in the template cavity, so that the template cavity is in a communicated state, the plastic scintillator or the nitrogen can be well filled, and the gas is completely pumped out when the vacuum is pumped.

In use, referring to fig. 1, 2 and 5, first-step reactor 1 is assembled: firstly, assembling the frame 11, and installing the upper frame 12 on the opening 111 of the frame 11 to form the outer frame 15; secondly, sequentially installing a first template 21, a partition plate 23 and a second template 22 in a template cavity 16 in the outer frame 15 to form a template 2, and repeatedly placing a plurality of layers of partition plates 23 and the formed templates 2 until the template cavity 16 is filled; next, sealing rings are placed in the sealing grooves 151 on both sides of the outer frame 15, the upper and lower cover plates 13 and 14 are closed on both sides of the outer frame 15, and the reaction vessel 1 is locked by screws. The disassembly process is reversed.

Secondly, cleaning the reaction kettle, namely cleaning the plastic scintillator polymerization reaction kettle according to the sequence of cleaning agent solution, pure water and pure water, wherein the cleaning agent can use acetone, and finally, the plastic scintillator polymerization reaction kettle is dried by nitrogen;

thirdly, testing the air tightness and pressure of the reaction kettle, and introducing nitrogen to circularly replace the air in the reaction kettle so as to keep the nitrogen environment in the reaction kettle;

fourthly, introducing the plastic scintillator into a reaction kettle 1 for polymerization reaction to form a plastic scintillator sheet;

and fifthly, disassembling the reaction kettle, operating the disassembling process according to the reverse direction of the first step, and taking out the plastic scintillator sheet.

According to the preparation method of the plastic scintillator sheet, the preparation device is used for carrying out three example tests and verifications as follows:

example 1

10 plastic scintillator sheets with the thickness of 0.5mm are prepared, and the base materials of the plastic scintillator sheets are styrene, 3% of luminescent agent p-terphenyl and 0.8% of wave-shifting agent 1, 4-bis (5-phenyl oxazole) benzene.

TABLE 1 10 samples of plastic scintillator sheets were prepared and tested at multiple points for average thickness (mm) with reference to FIG. 8

1	2	3	4	5	6	7	8	9	10
										0.503	0.508	0.509	0.493	0.502	0.490	0.507	0.501	0.495	0.511

Example 2

10 pieces of plastic scintillator sheets with a thickness of 0.35mm were prepared, the base material of the plastic scintillator sheets was methyl methacrylate, the luminescent agent was 2- (4-biphenyl) -5-phenyl oxadiazole 5%, and the wave shifter was 9, 10-diphenylanthracene 0.6%.

TABLE 2 10 samples of plastic scintillator sheets were prepared and tested at multiple points for average thickness (mm) with reference to FIG. 8

1	2	3	4	5	6	7	8	9	10
										0.353	0.358	0.349	0.353	0.352	0.350	0.347	0.351	0.345	0.351

Example 3

10 plastic scintillator sheets with the thickness of 0.25mm are prepared, and the base material of the plastic scintillator sheets is vinyl toluene: methyl methacrylate 1:1, 7% luminophore 2, 5-diphenyloxazole: 2- (4-biphenyl) -5-phenyl oxadiazole ═ 1:2 and 0.3% wave-shifting agent 1, 4-bis (5-phenyl-2-oxazolyl) benzene: 9, 10-diphenylanthracene ═ 1: 3.

TABLE 3 10 samples of plastic scintillator sheets were prepared and tested at multiple points to determine the average thickness (mm) with reference to FIG. 8

1	2	3	4	5	6	7	8	9	10
										0.251	0.252	0.249	0.251	0.252	0.251	0.249	0.251	0.251	0.250

The obtained plastic scintillator sheet sample has a smooth and flat surface as shown in fig. 7; FIG. 8 and tables 1-3 show the thickness test results for plastic scintillator sheets, with the average thickness consistent with the expected thickness and the relative thickness deviation within 3% for different locations; FIG. 9 shows the emission spectrum of a plastic scintillator sheet sample with a thickness of 0.5mm, with a maximum wavelength of about 423nm, in the blue light band. The plastic scintillator sheet can well meet the measurement requirements of low-energy alpha and beta rays.

It should be noted that the above-mentioned preferred embodiments are merely illustrative of the technical concepts and features of the present invention, and are intended to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the scope of the present invention. All equivalent changes and modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.