Preparation method and application of fast neutron scintillation screen

Abstract

The invention relates to the technical field of functional materials, in particular to a preparation method and application of a fast neutron scintillation screen. The preparation method of the fast neutron scintillation screen comprises the following steps: (1) preparing a perovskite fast neutron scintillator material; and (2) preparing a scintillation screen by using a hydrogen-rich substrate packaging luminescent material, wherein S1, the hydrogen-rich substrate and a scintillator material are prepared: the scintillator material in the step (1) is dissolved in a solvent for ultrasonic treatment; meanwhile, taking a proper amount of hydrogen-rich matrix, heating and dissolving the hydrogen-rich matrix into a liquid state at high temperature, adding the solution subjected to ultrasonic treatment into the dissolved hydrogen-rich matrix, and stirring until the solvent is completely volatilized to obtain a mixed solution in which the scintillator material and the hydrogen-rich matrix are completely mixed; s2, the fast neutron scintillation screen is prepared, specifically, the mixed solution in the S1 is cast into a mold to be prepared into a thin film, the fast neutron scintillation screen can freely fall off after a moment, and the fast neutron scintillation screen is obtained. The three types of fast neutron scintillation screens prepared by the method have good luminous efficiency and spatial resolution under the irradiation of fast neutrons, and show huge potential in fast neutron imaging.

Description

Technical Field

[0001] The present invention relates to the technical field of functional materials, and particularly to a preparation method and application of a fast neutron scintillation screen. Background Art

[0002] Fast neutron imaging, as a non-destructive testing method, has become an important supplement to technologies such as thermal neutron imaging, X-ray imaging, and γ imaging, and has been widely applied in many fields. Since fast neutrons have strong penetration ability in matter, compared with other imaging technologies, fast neutrons can image materials with larger volume and higher density. The conversion screen plays a key role in imaging. It converts neutrons into visible light and is received by the detection system for imaging. Its performance has a great impact on the imaging effect.

[0003] Fast neutron conversion screens are mainly composed of hydrogen-containing materials and fluorescent materials. Existing common conversion screens include mixed-pressure conversion screens such as ZnS(Ag):PP and PZC, plastic scintillators (PS), fiber optic conversion screens (OFCS), etc. However, such scintillation screens have defects such as uneven distribution of fluorescent substances in the matrix, low luminous efficiency, and long afterglow, which affect the detection efficiency and spatial resolution. Therefore, it is particularly important to develop new fast neutron detection materials with high luminous efficiency and fast lifetime. Summary of the Invention

[0004] In order to make up for the deficiencies of the prior art, the present invention provides a preparation method and application of a fast neutron scintillation screen. The three fast neutron scintillation screens prepared by this method all have good luminous efficiency and spatial resolution under fast neutron irradiation, showing great potential in the field of fast neutron imaging, and solving the problems existing in the prior art.

[0005] One of the technical solutions adopted by the present invention to achieve the above invention purpose is:

[0006] A preparation method of a fast neutron scintillation screen, comprising the following operating steps:

[0007] (1) Preparation of perovskite fast neutron scintillator material;

[0008] (2) Using a hydrogen-rich matrix to encapsulate the scintillator material to prepare a scintillation screen;

[0009] S1 Prepare a hydrogen-rich matrix and a scintillator material

[0010] Dissolve the scintillator material prepared in step (1) in a solvent and perform ultrasonic treatment to obtain an ultrasonic solution; at the same time, take an appropriate amount of hydrogen-rich matrix, heat it at a high temperature to dissolve it into a liquid state, add the ultrasonic solution to the dissolved hydrogen-rich matrix, and stir until the solvent completely volatilizes to obtain a mixed solution in which the scintillator material and the hydrogen-rich matrix are completely mixed;

[0011] S2 Prepare a fast neutron scintillation screen

[0012] Pour the S1 mixture into a mold to prepare a thin film. Wait for a moment, and the fast neutron scintillator screen can fall off freely, thus obtaining it.

[0013] Further, the hydrogen-rich matrix in step (2) is one or more of polyethylene wax, paraffin wax, and beeswax; the hydrogen content of the hydrogen-rich matrix is 13% - 15%; the solvent is n-hexane or ethyl acetate.

[0014] Further, the hydrogen-rich matrix in step (2) is polyethylene wax, and the hydrogen content of polyethylene wax is 14%.

[0015] Further, the ultrasonic treatment time of S1 in step (2) is 5 - 20 min, the hydrogen-rich matrix is heated at a high temperature of 110 °C; the mass ratio of the scintillator material to the hydrogen-rich matrix is 1:15 to 1:4; the film thickness of S2 is 1 - 4 mm.

[0016] Further, the film thickness is 1.5 - 2.5 mm.

[0017] Further, the perovskite fast neutron scintillator material in step (1) is a hydrogen-rich two-dimensional organic-inorganic perovskite material doped with metal ions or a zero-dimensional lead-free perovskite material.

[0018] Further, the metal ion is Mn 2+ or Sn 2+ .

[0019] Further, the hydrogen-rich two-dimensional organic-inorganic perovskite material is (C 16 H 33 NH 3 ) 2 PbBr 4 or (C 8 H 12 N) 2 PbBr 4 ; the zero-dimensional lead-free perovskite material is Cs 3 Cu 2 I 5 .

[0020] Further, the steps for preparing the scintillator material Mn:(HDA) 2+ (C 16 H 33 NH 3 ) 2 PbBr 4 doped with Mn are as follows: 2 PbBr 4 are as follows:

[0021] Prepare HDABr in S1

[0022] Dissolve hexadecylamine (HDA) in a mixed solution of appropriate amounts of acetic acid and hydrobromic acid (HBr). After stirring at room temperature for 2 h, centrifuge to obtain a white precipitate; wash the white precipitate with acetic acid two more times, and take the precipitate and dissolve it in absolute ethanol; evaporate the ethanol from the solution at high temperature to obtain white crystals - HDABr;

[0023] S2 Preparation of (HDA) 2 PbBr 4

[0024] Take an appropriate amount of HDABr prepared in S1 and PbBr 2 Mix them in a molar ratio of 2:1 and dissolve them in DMSO or H 2 O. Stir at high temperature for 4 h, then centrifuge to obtain a white precipitate. Wash it with water two times and then dissolve it in water. Freeze-dry to obtain a white powder - (HDA) 2 PbBr 4 ;

[0025] S3 Preparation of Mn:(HDA) 2 PbBr 4

[0026] Take the white powder prepared in S2 and an appropriate amount of MnBr 2 Mix them and place them in a mortar and grind for a while to obtain a pinkish powder that emits orange-yellow under ultraviolet light. Then, seal it with plastic wrap and bake it in an oven at high temperature for 10 h to obtain it.

[0027] Furthermore, the steps for doping Mn 2+ into (C 8 H 12 N) 2 PbBr 4 to prepare the scintillator material Mn:(PEA) 2 PbBr 4 are as follows:

[0028] S1 Preparation of PEABr

[0029] Add hydrobromic acid (HBr) and β-phenethylamine (PEA) to an anhydrous methanol solvent respectively, and stir at room temperature for 2 hours; heat and stir at 50 °C to evaporate the methanol solvent to obtain a white precipitate; vacuum dry it to obtain phenethylammonium bromide PEABr powder;

[0030] S2 Preparation of Mn:(PEA) 2 PbBr 4

[0031] Take the PEABr prepared in S1 and PbBr 2 and MnBr and add them to an agate mortar, grind for 20 min to make them react fully; obtain Mn:(PEA) 2PbBr 4 Powder;

[0032] S3 Pretreatment of Mn:(PEA) 2 PbBr 4

[0033] Take the Mn:(PEA) prepared in S2 2 PbBr 4 The white powder is placed in a glass bottle and heated in a vacuum drying oven at 120 °C for 2 h. After the Mn:(PEA) 2 PbBr 4 powder cools naturally, it is obtained.

[0034] Furthermore, doping Sn 2+ into Cs 3 Cu 2 I 5 to prepare the scintillator material Cs 3 Cu 2 I 5 / Cs 3 Cu 2 I 5 :Sn is as follows:

[0035] S1 Preparation of precursor solution

[0036] Take CsI, CuI, DMF and DMSO, or CsI, CuI, SnI 2 , DMF and DMSO, mix them, and vigorously stir the resulting mixture at 60 °C for 30 min to dissolve it, thus obtaining the precursor solution;

[0037] S2 Anti-solvent extraction

[0038] Take the precursor solution prepared in S1, add toluene as an anti-solvent to the precursor solution, and a large amount of white powder appears. The ratio of the precursor to the anti-solvent is 1:4;

[0039] S3 Preparation of Cs 3 Cu 2 I 5 / Cs 3 Cu 2 I 5 :Sn

[0040] Centrifuge the mixed solution of S2 to obtain a white precipitate; wash the white precipitate twice with n-hexane, transfer it to a vacuum drying oven to dry for 8 h, then grind and sieve it to obtain Cs 3 Cu 2 I 5 / Cs 3 Cu 2 I 5: Sn scintillator material.

[0041] The second technical solution adopted by the present invention is:

[0042] Provide the application of the fast neutron scintillation screen prepared by the preparation method as described above in the field of fast neutron imaging.

[0043] Furthermore, the above application is the application of the fast neutron scintillation screen prepared as described above on an imaging device; the imaging device is a CCD camera. Specifically, fast neutrons irradiate the fast neutron scintillation screen after passing through the imaging sample, exciting the scintillator to emit visible fluorescence. Then, the imaging device converts the optical signal into a digital image, thereby achieving the purpose of detection and imaging.

[0044] Furthermore, the above application is to attach the fast neutron scintillation screen to the inner side of an aluminum plate. The aluminum plate seals the dark box to prevent light leakage. The detector is placed at the rear end of the neutron scintillation screen. The fast neutron screen absorbs neutrons to generate visible light, and the generated scintillation light is captured by the CCD camera and converted into a digital image to complete imaging.

[0045] Advantages of the present invention:

[0046] 1. The present invention embeds three fast neutron scintillator materials into the hydrogen-rich matrix PEW respectively to prepare a fast neutron scintillation screen. The hydrogen content of the hydrogen-rich matrix PEW can reach 14%. The preparation operation is simple, fast, and low in cost, and the prepared scintillation screen has high luminous efficiency and high resolution.

[0047] 2. The three fast neutron scintillator materials prepared by the present invention have good luminous efficiency and spatial resolution at fast neutron energies, and all show great potential in the field of fast neutron imaging. Among them, (HDA) + , (PEA) + is an amino ligand with a long carbon chain, which provides a large number of hydrogen atoms to quickly respond to fast neutron radiation; Mn 2+ doping reduces the self-absorption of the material and can optimize the luminous efficiency and scintillation performance. The zero-dimensional perovskite material Cs 3 Cu 2 I 5 such a special low-dimensional structure leads to a strong quantum confinement effect, resulting in a wide spectral emission and a large Stokes shift, avoiding self-absorption and ensuring the necessary transparency of the scintillator itself to reduce the loss of light output; Sn 2+ doping, without affecting the position of the main emission peak, causes the densification of its structure and enhances the photoluminescence quantum yield (PLQY). By using the above three different fast neutron scintillator materials to prepare the fast neutron scintillation screen of the present invention respectively, a fast neutron scintillation screen with higher resolution and high-quality imaging is obtained. Description of the drawings

[0048] Figure 1 Flow chart for the preparation of the fast neutron scintillator screen in Example 1;

[0049] Figure 2 Physical picture of the fast neutron scintillator screen prepared in Example 1; among them, the left picture is under sunlight, and the right picture is under ultraviolet irradiation;

[0050] Figure 3 Physical picture of the fast neutron scintillator screen prepared in Example 2; among them, the left picture is under sunlight, and the right picture is under ultraviolet irradiation;

[0051] Figure 4 PLE / PL spectrogram of the fast neutron scintillator screens of Example 1 and Example 2; among them, the left picture is the data graph of Example 1, and the right picture is the data graph of Example 2;

[0052] Figure 5 Comparison graph of the photos and absolute gray values of the fast neutron scintillator screen of Example 1 and the commercial screen ZnS(Ag):PP under fast neutron irradiation, and its brightness accounts for 65.8% of the commercial screen;

[0053] Figure 6 Flow chart for the preparation of the fast neutron scintillator screen in Example 3;

[0054] Figure 7 PLE / PL spectrogram of the scintillator material in Example 3;

[0055] Figure 8 In (a) is the physical picture of the fast neutron scintillator screen in Example 3, (b) is the photo under ultraviolet lamp irradiation, and (c) is the photo under fast neutron irradiation;

[0056] Figure 9 Resolution photo of Example 3 as a scintillator screen, among which, (a) is the physical photo of the resolution test standard sample; (b) is the resolution imaging of the scintillator screen under fast neutron irradiation;

[0057] Figure 10 PLE / PL spectrogram of the scintillator material in Example 4;

[0058] Figure 11 Physical picture of the fast neutron scintillator screen in Example 4, as shown in (a) in the figure, the photo under ultraviolet lamp irradiation is shown in (b) in the figure, and the photo under fast neutron irradiation is shown in (c) in the figure;

[0059] Figure 12 Resolution photo of Example 4 as a scintillator screen, among which, (a) is the physical photo of the resolution test standard sample; (b) is the resolution imaging of the scintillator screen under fast neutron irradiation;

[0060] Figure 13Figure of the physical object of the neutron scintillator screen under Example 5, as shown in (a) in the figure, the photo under ultraviolet lamp irradiation is shown in (b) in the figure, and the photo under fast neutron irradiation is shown in (c) in the figure;

[0061] Figure 14 Resolution photos of the scintillator screen in Example 5, (a) Physical photo of the resolution test standard sample; (b) Resolution imaging of the scintillator screen under fast neutron irradiation. Detailed implementation manners

[0062] To clearly illustrate the technical features of this solution, the present invention will be elaborated in detail below through specific implementation manners in combination with the accompanying drawings. The scope of the present invention is not limited to the following embodiments. Professionals in the field can understand that various changes and modifications can be made to the present invention without departing from the spirit and scope of the present invention.

[0063] For the instruments, reagents, materials, etc. involved in the following embodiments, unless otherwise specified, they are all conventional instruments, reagents, materials, etc. existing in the prior art and can be obtained through regular commercial channels. For the experimental methods, detection methods, etc. involved in the following embodiments, unless otherwise specified, they are all conventional experimental methods, detection methods, etc. existing in the prior art.

[0064] Example 1

[0065] A preparation method of a manganese-doped two-dimensional Pb-based perovskite fast neutron scintillator screen includes the following operating steps:

[0066] (1) Dissolve 10 mmol of hexadecylamine (HDA) in a mixed solution of 10 ml of acetic acid and 10 mmol of hydrobromic acid (HBr), stir at room temperature for 2 h, then centrifuge at 10000 r for 5 min to obtain a white precipitate; wash the white precipitate with acetic acid two more times, and take the precipitate and dissolve it in absolute ethanol; place the solution at 80 °C for 5 h - 8 h, and after the ethanol volatilizes, obtain a white crystal - HDABr;

[0067] (2) Take the HDABr prepared in (1) and PbBr 2 Mix them in a molar ratio of 2:1 and dissolve them in 20 ml of DMSO, stir at 90 °C for 4 h, then centrifuge at 10000 r for 5 min to precipitate a white solid, wash it with water two times, and then dissolve it in an appropriate amount of water, and freeze-dry for 10 h - 12 h to obtain a white powder - (HDA) 2 PbBr 4 ;

[0068] (3) Take the white powder prepared in (2) and an appropriate amount of MnBr 2Mix them in a molar ratio of 5:1, grind them in a mortar for 15 - 20 min, and obtain an orange - pink powder that emits light under ultraviolet light irradiation. Then, seal it with plastic wrap and bake it in an oven at about 90 °C for 10 h to obtain the scintillator material;

[0069] (4) Take 0.8 g of the scintillator material prepared in (3), dissolve it in 20 ml of n - hexane, and perform ultrasonic treatment for 20 min; at the same time, take 6 g of polyethylene wax (matrix) and heat it to 110 °C to dissolve it into a liquid state; after the matrix is completely dissolved into a liquid state, take the ultrasonicated solution and add it to the matrix and stir until the n - hexane completely volatilizes (about 3 min) to obtain a mixed solution in which the scintillator material and the matrix are completely mixed;

[0070] (5) Pour the mixed solution obtained in (4) into a mold and wait for 10 min, then the neutron screen can fall off freely, and the fast neutron scintillation screen is prepared.

[0071] See Figure 1 for the preparation flow chart of the above - mentioned fast neutron scintillation screen; Figure 2 for the physical diagram. Combining Figure 5 the brightness comparison between the fast neutron scintillation screen of this example provided and the current commercial screen, it can be clearly seen that under fast neutron irradiation, the brightness of the fast neutron scintillation screen of the present invention accounts for 65.8% of the commercial screen, and there is a great improvement in the luminous efficiency compared with other perovskite fast neutron screens, providing a new material guarantee for high - imaging - quality and high - resolution fast neutron imaging.

[0072] Example 2

[0073] A preparation method of a manganese - doped two - dimensional Pb - based perovskite fast neutron scintillation screen is as follows:

[0074] (1) Dissolve 10 mmol of hexadecylamine (HDA) in a mixed solution of 10 ml of acetic acid and 10 mmol of hydrobromic acid (HBr), stir at room temperature for 2 h, then centrifuge at 10000 r for 5 min to obtain a white precipitate; wash the white precipitate with acetic acid two more times, and take the precipitate and dissolve it in absolute ethanol; place the solution at 80 °C for 5 - 8 h, and after the ethanol volatilizes, obtain a white crystal - HDABr;

[0075] (2) Take the HDABr prepared in (1) and mix it with PbBr2 in a molar ratio of 2:1 and dissolve it in 20 ml of H 2 O, stir at 90 °C for 4 h, then centrifuge at 10000 r for 5 min to obtain a white precipitate, wash it with water two times, and then dissolve it in an appropriate amount of water and freeze - dry it for 10 - 12 h to obtain a white powder - (HDA) 2 PbBr 4 ;

[0076] (3) Take the white powder prepared in (2) and an appropriate amount of MnBr 2Mix with a molar ratio of 5:1, place in a mortar and grind for 15 - 20 min. It emits an orange - pinkish powder under ultraviolet light irradiation. Then, seal it with plastic wrap and bake it in an oven at about 90 °C for 10 h to obtain the scintillator material;

[0077] (4) Take 0.8 g of the scintillator material prepared in (3) and dissolve it in 20 ml of n - hexane, then ultrasonically treat it for 20 min; at the same time, take 6 g of polyethylene wax (matrix) and heat it to 110 °C to dissolve it into a liquid state; after the matrix is completely dissolved into a liquid state, take the ultrasonically treated solution and add it to the matrix, and stir until the n - hexane completely evaporates (about 3 min) to obtain a mixed solution in which the scintillator material and the matrix are completely mixed;

[0078] (5) Pour the mixed solution into a mold and wait for 10 min, then the neutron screen can fall off freely, and the fast neutron scintillation screen is prepared.

[0079] As Figure 3 , the physical picture of the above - prepared fast neutron scintillation screen is given.

[0080] From Figure 4 The PLE / PL spectra of the fast neutron scintillation screens of Examples 1 and 2 given, it can be seen that the PL spectrum of Mn 2+ - doped (HDA) 2 PbBr 4 shows a strong emission peak at 385 nm, the highest peak position of its excitation peak is 620 nm, and the peaks basically do not overlap, showing a large Stokes shift (235 nm).

[0081] Example 3

[0082] A preparation method of a manganese - doped two - dimensional Pb - based perovskite fast neutron scintillation screen is as follows:

[0083] (1) Add 1 ml of hydrobromic acid (HBr) and 1 ml of β - phenethylamine (PEA) to 5 ml of anhydrous methanol solvent respectively, and stir at room temperature for 2 hours; then, heat and stir at 50 °C to volatilize the methanol solvent to obtain a white precipitate; subsequently, place it in a vacuum drying oven, and after drying, obtain phenethylammonium bromide (PEABr) powder. Finally, place the powder in a dry brown glass bottle and store it away from light;

[0084] (2) Take 0.5 mmol of the PEABr prepared in (1) and 1 mmol of PbBr 2 , 0.5 mmol of MnBr and add them to an agate mortar, grind for 20 min to make them react fully, and obtain Mn:(PEA) 2 PbBr 4 powder;

[0085] (3) Take the white powder prepared in (2) and place it in a glass bottle. Heat it in a vacuum drying oven at 120 °C for 2 h until Mn:(PEA) 2 PbBr 4 After the powder cools naturally, a scintillator material is obtained;

[0086] (4) Take 0.45 g of the scintillator material prepared in (3) and dissolve it in 5 ml of ethyl acetate, then ultrasonically treat it for 20 min. At the same time, take 6 g of polyethylene wax (matrix) and heat it to 110 °C until it dissolves into a liquid state. After the matrix is completely dissolved into a liquid state, take the ultrasonically treated solution and add it to the matrix, and stir until the ethyl acetate completely volatilizes (about 3 min) until the scintillator material and the matrix are completely mixed to obtain a mixed solution;

[0087] (5) Pour the mixed solution into a mold and wait for 10 min until the neutron screen can fall off freely, and the fast neutron scintillator screen is prepared.

[0088] Combined Figure 7 , it can be seen that the excitation peak of the scintillator material prepared in Example 3 is 365 nm, the emission peak is 610 nm, and the Stokes shift can reach 245 nm. In addition, from Figure 8 it can be seen that the scintillator screen has bright luminescence under fast neutron irradiation and can resolve the slit( Figure 9 ).

[0089] Example 4

[0090] A preparation method of a zero-dimensional Cu-based perovskite fast neutron scintillator screen is as follows:

[0091] (1) Take 3 mmol of CsI, 2 mmol of CuI, 4 mL of DMF, and 1 mL of DMSO and add them to a beaker. Stir the resulting mixture vigorously at 60 °C for 30 min until it dissolves to obtain a precursor solution;

[0092] (2) Take the precursor solution prepared in (1) and add toluene as an antisolvent to the precursor solution. A large amount of white powder will appear in the beaker, and the ratio of the precursor to toluene is 1:4;

[0093] (3) Transfer the mixed solution in the beaker in (2) to a centrifuge tube and centrifuge it at 10000 r / min for 10 min to obtain a white precipitate. Wash the white precipitate twice with n-hexane, transfer it to a vacuum drying oven, dry it for 8 h, grind it into a powder, and sieve it through a 200-mesh sieve to obtain Cs 3 Cu 2 I 5 scintillator material;

[0094] (4) Take 1.5 g of the scintillator material prepared in (3) and dissolve it in 5 ml of ethyl acetate, then ultrasonically treat it for 5 min; simultaneously, take 6 g of polyethylene wax (matrix) and heat it to 110 °C until it dissolves into a liquid state; after the matrix is completely dissolved into a liquid state, take the ultrasonically treated solution and add it to the matrix, and stir until the ethyl acetate completely volatilizes (about 3 min) until the scintillator material and the matrix are completely mixed to obtain a mixed solution;

[0095] (5) Pour the mixed solution in (4) into a mold and wait for 10 min, then the neutron screen can fall off freely, and the fast neutron scintillation screen is prepared.

[0096] From Figure 10 the PLE / PL spectra of Example 4 in 3 Cu 2 I 5 it can be seen that the positions of the excitation peak and emission peak of the Cs

[0097] Example 5

[0098] A preparation method of a zero-dimensional Cu-based perovskite fast neutron scintillation screen based on tin doping is as follows:

[0099] (1) Take 3 mmol of CsI, 2 mmol of CuI, 0.003 mmol of SnI 2 , 4 mL of DMF and 1 mL of DMSO and add them to a beaker, and vigorously stir the obtained mixture at 60 °C for 30 min to dissolve it, thus obtaining a precursor solution;

[0100] (2) Take the precursor solution prepared in (1), add toluene as an antisolvent to the precursor solution, and a large amount of white powder will appear in the beaker, where the ratio of the precursor to toluene is 1:4;

[0101] (3) Transfer the mixed solution in the beaker in (2) to a centrifuge tube, centrifuge it at 10000 r / min for 10 min to obtain a white precipitate; wash the white precipitate twice with n-hexane, transfer it to a vacuum drying oven and dry it for 8 h, then grind it into a powder and sieve it through a 200-mesh sieve to obtain the tin-doped Cs 3 Cu 2 I 5 scintillator material;

[0102] (4) Take 1.5 g of the scintillator material prepared in (3) and dissolve it in 5 ml of ethyl acetate, then ultrasonically treat it for 5 min; simultaneously, take 6 g of polyethylene wax (matrix) and heat it to 110 °C until it dissolves into a liquid state; after the matrix is completely dissolved into a liquid state, take the ultrasonically treated solution and add it to the matrix, and stir until the ethyl acetate completely volatilizes (about 3 min) until the scintillator material and the matrix are completely mixed to obtain a mixed solution;

[0103] (5) Pour the mixture obtained in (4) into a mold and wait for 10 min until the neutron screen can fall off freely, and the fast neutron scintillation screen is prepared.

[0104] Combined with Figure 11 、 12 、13, and 14, it can be seen that the fast neutron scintillation screens prepared in Examples 4 and 5 have bright luminescence under fast neutron irradiation and high intensity; and in the single-slit test, the slit can be clearly distinguished, and even a relatively thin slit can be well reproduced.

[0105] The above specific embodiments cannot be used as a limitation to the protection scope of the present invention. For those skilled in the art of this technology, any alternative improvement or transformation made to the embodiments of the present invention falls within the protection scope of the present invention.

[0106] Where the present invention is not described in detail, it is all well-known techniques to those skilled in the art of this technology.

Claims

1. A method for preparing a fast neutron scintillation screen, characterized in that: The steps are as follows: (1) Preparation of perovskite fast neutron scintillator materials; (2) Preparation of scintillator screens using hydrogen-rich matrix encapsulated scintillator materials S1 Preparation of hydrogen-rich matrix and scintillator materials The scintillator material prepared in step (1) is dissolved in a solvent and subjected to ultrasonic treatment to obtain an ultrasonic solution; at the same time, an appropriate amount of a hydrogen-rich matrix is ​​heated at high temperature to dissolve into a liquid state, and the ultrasonic solution is added to the dissolved hydrogen-rich matrix and stirred until the solvent is completely volatilized to obtain a mixed solution in which the scintillator material and the hydrogen-rich matrix are completely mixed; S2 preparation of fast neutron scintillation screen Cast the S1 mixed liquid into a mold to prepare a thin film, wait for a while, and the fast neutron scintillation screen will fall off freely.

2. The method for preparing a fast neutron scintillation screen according to claim 1, characterized in that: In step (2), the hydrogen-rich matrix is ​​one or more of polyethylene wax, paraffin wax, and beeswax; the hydrogen content of the hydrogen-rich matrix is ​​13%-15%; and the solvent is n-hexane or ethyl acetate.

3. The method for preparing a fast neutron scintillation screen according to claim 1, characterized in that: The ultrasonic treatment time of step (2) S1 is 5-20 minutes, the hydrogen-rich matrix is ​​heated at a high temperature of 110° C., the mass ratio of the scintillator material to the hydrogen-rich matrix is ​​1:15 to 1:4; and the film thickness of S2 is 1 to 4 mm.

4. The method for preparing a fast neutron scintillation screen according to claim 1, characterized in that: The perovskite fast neutron scintillator material in step (1) is a hydrogen-rich two-dimensional organic-inorganic perovskite material doped with metal ions or a zero-dimensional lead-free perovskite material.

5. The method for preparing a fast neutron scintillation screen according to claim 4, characterized in that: The metal ion is Mn 2+ or Sn 2+ .

6. The method for preparing a fast neutron scintillation screen according to claim 5, characterized in that: The hydrogen-rich two-dimensional organic-inorganic perovskite material is (C 16 H 33 NH3)2PbBr4 or (C8H 12 N)2PbBr4; the zero-dimensional lead-free perovskite material is Cs3Cu2I5.

7. The method for preparing a fast neutron scintillation screen according to claim 6, characterized in that: Mn doping 2+ (C 16 H 33 The steps for preparing the scintillator material Mn:(HDA)2PbBr4 from NH3)2PbBr4 are as follows: S1 Preparation of HDABr Dissolve hexadecylamine in a mixed solution of appropriate amounts of acetic acid and hydrobromic acid, stir at room temperature for 2 hours, and centrifuge to obtain a white precipitate; continue to wash the white precipitate with acetic acid twice, and dissolve the precipitate in anhydrous ethanol; place the solution at high temperature to evaporate the ethanol to obtain white crystals - HDABr; S2 Preparation (HDA)2PbBr4 Take an appropriate amount of HDABr and PbBr2 prepared in S1 and mix them in a molar ratio of 2:1 and dissolve them in DMSO or H2O, stir at high temperature for 4 hours, then centrifuge to get a white precipitate, wash it twice with water, dissolve it in water, and freeze-dry it to get a white powder - (HDA)2PbBr4; S3 Preparation of Mn:(HDA)2PbBr4 Take the white powder prepared in S2 and mix it with an appropriate amount of MnBr2, place it in a mortar and grind it for a while to obtain an orange-pink powder under ultraviolet light. Then wrap it with plastic wrap and bake it in an oven at high temperature for 10 hours.

8. The method for preparing a fast neutron scintillation screen according to claim 6, characterized in that: Mn doping 2+ (C8H 12 The steps for preparing the scintillator material Mn:(PEA)2PbBr4 are as follows: S1 Preparation of PEABr Add hydrobromic acid and β-phenylethylamine to anhydrous methanol solvent respectively, and stir at room temperature for 2 hours; heat and stir at 50°C to volatilize the methanol solvent to obtain a white precipitate; and vacuum dry the precipitate to obtain phenethylammonium bromide PEABr powder; S2 Preparation of Mn:(PEA)2PbBr4 Take the PEABr prepared in S1, PbBr2 and MnBr and add them into an agate mortar, grind for 20 minutes to allow them to react fully; obtain Mn:(PEA)2PbBr4 powder; S3 Pretreatment Mn:(PEA)2PbBr4 The white powder prepared in S2 is placed in a glass bottle and heated in a vacuum drying oven at 120°C for 2 h. The Mn:(PEA)2PbBr4 powder is obtained after it is naturally cooled.

9. The method for preparing a fast neutron scintillation screen according to claim 6, characterized in that: Sn doping 2+ The steps of preparing the scintillator material Cs3Cu2I5 / Cs3Cu2I5:Sn from Cs3Cu2I5 are as follows: S1 Preparation of precursor solution CsI, CuI, DMF and DMSO, or CsI, CuI, SnI2, DMF and DMSO are mixed, and the resulting mixture is vigorously stirred at 60°C for 30 minutes to dissolve, thereby obtaining a precursor solution; S2 Anti-Solvent Extraction Take the precursor solution prepared in S1, add toluene as an anti-solvent to the precursor solution, and a large amount of white powder appears, wherein the ratio of precursor to anti-solvent is 1:4; Preparation of Cs3Cu2I5 / Cs3Cu2I5:Sn by S3 The mixed solution of S2 was centrifuged to obtain a white precipitate; the white precipitate was washed twice with n-hexane, transferred to a vacuum drying oven and dried for 8 hours, then ground and sieved to obtain Cs3Cu2I5 / Cs3Cu2I5:Sn scintillator material.

10. Application of the fast neutron scintillation screen prepared by the preparation method according to any one of claims 1 to 9 in the field of fast neutron imaging.

Images