Multilayer super-structured scintillator with micro-cavity structure and preparation method thereof

Abstract

This invention discloses a multilayer metascintillator with a microcavity structure, addressing the technical problems of existing scintillators fabricated using thin-film methods, such as uneven surface microscales and significant performance dependence on environmental temperature and humidity. The invention comprises a substrate scintillator, a microcavity disposed within the substrate scintillator, and a modulating material filling the microcavity and interlayer gaps. The substrate scintillator consists of multiple monolayer substrate scintillators. The microcavity is formed by complementary microcavity lobes arranged on the bonding surfaces of adjacent monolayer substrate scintillators; the microcavity lobe size is on the order of nm to μm. This invention fabricates a microcavity within the scintillator, enabling internal optical path modulation and improving the scintillator's emission distribution. Placing the modulating material inside the scintillator allows for timely and efficient modulation of the scintillator's emission wavelength, reducing self-absorption and increasing the scintillator's luminous efficiency.

Description

Technical Field

[0001] This invention relates to the field of scintillator radiation detectors, and more specifically to a multilayer metascintillator with a microcavity structure and its fabrication method. Background Technology

[0002] In nuclear radiation detection, scintillators are a fundamental yet indispensable key material. They convert high-energy particles and rays into light, which is then converted by a photodetector into an electrical signal carrying rich radiation field information. This signal is widely used in neutron diagnostics, gamma measurements, and transient imaging of pulsed radiation fields. Since the luminescence time and efficiency of scintillators determine the key performance characteristics of scintillation detection systems, such as time resolution and energy resolution, the research and development of fast and efficient scintillators has always been a pursuit and direction of effort in the field of nuclear radiation detection.

[0003] However, among the diverse types of scintillators, speed and efficiency are difficult to achieve simultaneously. To meet the demands of high-energy-density physical diagnostics and pulsed radiation detection, scintillator materials need nanosecond-level decay times and high luminous efficiency. Wide-bandgap semiconductors such as ZnO and CuI can achieve sub-nanosecond luminescence times, but their luminous efficiency is low; BaF2 has nanosecond-level luminescence times, but it exhibits both fast and slow components. Therefore, combining and modifying existing materials has become another key approach in applied technology research.

[0004] Chinese patent application CN202111228351.4 proposes a composite scintillator based on a perovskite-scintillator single crystal and its preparation method. The method primarily involves directly fabricating a perovskite quantum dot film on the surface of the scintillator single crystal to obtain a bilayer composite scintillator. This approach leverages the near 100% quantum yield and wave-shifting properties of perovskite to improve the external quantum efficiency and light yield of the scintillator. Furthermore, tunable wavelength emission of the composite scintillator is achieved by adjusting the halogen ratio of the perovskite. However, the aforementioned composite structure and preparation method are simple bilayer structures, and their control only occurs on the surface of the scintillator single crystal. This results in insufficiently timely absorption and conversion of scintillator light emission, limiting the increase in conversion efficiency and light yield. The interface between the perovskite thin film and the substrate scintillator is undesigned and subject to limited conditions. This film preparation method results in microscopic unevenness on the surface of the perovskite quantum dot film. Furthermore, due to the softness of the prepared film, it is difficult to flatten or perform secondary processing after molding, making it impossible to directionally improve the scintillator's luminescence distribution. At the same time, the perovskite quantum dot film is greatly affected by environmental temperature and humidity, and its various properties change significantly over time, resulting in a short lifespan that does not meet the requirements of practical applications. Summary of the Invention

[0005] The purpose of this invention is to solve the technical problems of existing scintillators prepared by thin film methods, which have uneven microscale surfaces and whose performance is greatly affected by environmental temperature and humidity. The invention provides a multilayer meta-scintillator with a microcavity structure and its preparation method. By creating a microcavity inside the scintillator, the optical path inside the scintillator can be controlled, improving the luminous emission distribution of the scintillator. Furthermore, by placing the control material inside the scintillator, the luminous efficiency of the scintillator is increased.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A multilayer metascintillator with a microcavity structure, characterized in that it includes a substrate scintillator and a plurality of microcavities disposed inside the substrate scintillator;

[0008] The substrate scintillator comprises multiple monolayer substrate scintillators stacked sequentially; the microcavity is formed by microcavity lobes complementaryly arranged on the bonding surface of two adjacent monolayer substrate scintillators; the microcavity lobe scale is on the order of nm to μm.

[0009] The microcavities and interlayer gaps are either in a vacuum or filled with control materials.

[0010] The multi-layer single-layer substrate scintillator (2) is sealed.

[0011] Furthermore, the substrate scintillator includes zinc oxide, barium fluoride, or a plastic scintillator.

[0012] Furthermore, the monolayer substrate scintillator has a nanosecond-level time response, a thickness of 20μm-200μm, a diameter of 5mm-50mm, and a quantity of 2-20 pieces.

[0013] Furthermore, the microcavity has a scale on the order of nm to μm and its shape includes spheres, ellipsoids, cylinders, or cones.

[0014] Furthermore, the control material includes an inert gas or a perovskite quantum dot solution.

[0015] Furthermore, the multiple single-layer substrate scintillators are sealed using homogeneous sleeves or vacuum sealant.

[0016] Furthermore, the control material is a perovskite quantum dot solution, and multiple microcavity lobes filled with perovskite quantum dot solution are disposed on the upper surface of the top monolayer substrate scintillator.

[0017] A method for preparing a multilayer metascintillator with a microcavity structure, characterized by the following steps:

[0018] Step 1: Pre-sort and number the multiple monolayer substrate scintillators, with the monolayer substrate scintillator to be used as the bottom surface being number 1.

[0019] Step 2: Microcavity flaps are fabricated on one or both sides of each monolayer substrate scintillator through micromachining;

[0020] Step 3: Fill the microcavity lobe with a control material on the bonding surface of two adjacent numbered monolayer substrate scintillators, and form a wet film on each surface.

[0021] Step 4: After the wet film has settled and become gel-like, align and press the two adjacent single-layer substrate scintillators together.

[0022] Step 5: After drying, follow the steps 3-4 to complete the splicing of all numbered single-layer substrate scintillators to form a multi-layer substrate scintillator.

[0023] Step 6: Seal the sides of the substrate scintillator and fill the gaps with a control material for sealing and fixation, thus obtaining a multilayer metascintillator with a microcavity structure.

[0024] A method for preparing a multilayer metascintillator with a microcavity structure, characterized by the following steps:

[0025] Step 1: Pre-sort and number the multiple monolayer substrate scintillators, with the monolayer substrate scintillator to be used as the bottom surface being number 1.

[0026] Step 2: Microcavity flaps are fabricated on one or both sides of each monolayer substrate scintillator by micromachining (6).

[0027] Step 3: Place the single-layer substrate scintillator in the vacuum operating chamber, align, attach, and compact it in sequence to form a multi-layer substrate scintillator.

[0028] Step 4: Apply a dense vacuum sealant to the side of the substrate scintillator for sealing;

[0029] Step 5: After the sealant has dried and set, slowly increase the pressure in the vacuum operating chamber and then restore the vacuum operating chamber to atmospheric pressure to obtain a multilayer metascintillator with a microcavity structure.

[0030] A method for preparing a multilayer metascintillator with a microcavity structure, characterized by the following steps:

[0031] Step 1: Pre-sort and number the multiple monolayer substrate scintillators, with the monolayer substrate scintillator to be used as the bottom surface being number 1.

[0032] Step 2: Microcavity flaps are fabricated on one or both sides of each monolayer substrate scintillator through micromachining;

[0033] Step 3: Place the single-layer substrate scintillator in the sealed operating chamber, evacuate and fill with nitrogen, and align, attach and press multiple single-layer substrate scintillators in sequence to form a multi-layer substrate scintillator.

[0034] Step 4: Apply a dense vacuum sealant to the side of the substrate scintillator for sealing;

[0035] Step 5: After the sealant has dried and solidified, connect the sealed operating chamber to the atmosphere to obtain a multilayer metascintillator with a microcavity structure.

[0036] Compared with the prior art, the present invention has the following beneficial technical effects:

[0037] 1. The method for preparing a multilayer metascintillator with a microcavity structure according to the present invention utilizes internally distributed microcavities and control materials to obtain a multidimensionally controllable metascintillator, which improves the external quantum efficiency and light yield of the substrate scintillator, changes the emission wavelength and emission angle distribution of the substrate scintillator, and enhances the adaptability of the substrate scintillator to complex pulse mixing fields.

[0038] 2. The method for preparing a multilayer metascintillator with a microcavity structure according to the present invention achieves microcavity embedding and non-surface optical modulation of the substrate scintillator. By controlling the volume of the substrate scintillator, the transmission distance of the luminescence emitted by the substrate scintillator within itself is further shortened, and the self-absorption effect of the scintillator is reduced. By adjusting the type of modulation material, the luminescence emitted by the substrate scintillator can be shifted, and the measurement capability of the metascintillator for specific rays in complex radiation fields can be directionally changed, enabling composite measurement of single radiation and composite measurement of multiple rays. By adjusting the size and structure of the microcavity, the control of the transmission optical path and the change of the luminescence distribution within the metascintillator are achieved.

[0039] 3. The method for preparing a multilayer metascintillator with a microcavity structure according to the present invention involves encapsulating the control material within the microcavity by the substrate scintillator material, which isolates it from air and moisture, extends the lifespan of the control material, and provides good environmental stability. This facilitates the repeated and long-term application of the metascintillator, providing a strong guarantee for its application in the field of nuclear radiation detection. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the structure of the multilayer metascintillator with microcavity structure of the present invention;

[0041] Figure 2 This is a schematic diagram of the microcavity splicing of the multilayer metascintillator of the microcavity structure of the present invention;

[0042] Figure 3The diagrams show the light emission control effect of the multilayer metascintillator with microcavity structure of the present invention; wherein, (a) is the light emission control effect under vacuum in the microcavity; (b) is the light emission control effect under CsPbBr3 quantum dot colloid filled in the microcavity; and (c) is the light emission control effect under no microcavity structure.

[0043] Figure 4 This is a schematic diagram of the control unit in the theoretical calculation of the multilayer metascintillator microcavity structure of the present invention;

[0044] The annotations in the attached figures are explained as follows:

[0045] 1-Substrate scintillator; 2-Monolayer substrate scintillator; 3-Microcavity; 4-Control material; 5-Homogeneous sleeve; 6-Microcavity lobe; 7-Control unit; 8-Control unit substrate; 9-Control unit microcavity; 10-Control unit control material. Detailed Implementation

[0046] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0047] See Figure 1 This invention discloses a multilayer meta-scintillator with a microcavity structure. The substrate scintillator 1 is zinc oxide, with a diameter of 42 mm and a thickness of 0.6 mm, and is composed of four monolayer substrate scintillators 2. In this embodiment, the monolayer substrate scintillator 2 is a thin zinc oxide layer. From bottom to top, the thicknesses of the thin zinc oxide layers are 0.2 mm, 0.2 mm, 0.1 mm, and 0.1 mm, respectively. Various ellipsoidal microcavities 3 are fabricated inside the substrate scintillator 1. The major axis dimensions of the microcavities 3 are 90 μm, 60 μm, and 30 μm, and the minor axis dimensions are 30 μm, 20 μm, and 10 μm. The direction of the major axis of the microcavity 3 is perpendicular to or at 45° to the normal direction of the bonding surface. The internal microcavities 3 are formed by combining the microcavity petals 6 on the lower surface of the upper thin zinc oxide layer and the microcavity petals 6 on the upper surface of the lower thin zinc oxide layer. The two microcavity petals 6 have the same cross-section on their respective surfaces, but their shapes and volumes may be different. The microcavities 3 are filled with a control material 4, which is an inert gas or a perovskite quantum dot solution. In this embodiment, the control material 4 is a solidified CsPbBr3 quantum dot solution, and the solvent of the CsPbBr3 quantum dot solution has both sealing and binding functions.

[0048] A sealing structure is provided on the outside of the substrate scintillator 1, which is formed by combining four single-layer substrate scintillators 2. This structure reduces the contact between the control material 4 and air and moisture in the air, further increasing the lifetime of the control material 4. The sealing structure may or may not be provided depending on the control material. In this embodiment, the side of the substrate scintillator 1 is sealed by a homogeneous sleeve 5, which is a zinc oxide sleeve. The homogeneous sleeve 5 has an inner diameter of 42.01 mm and an outer diameter of 50 mm. The inner wall of the sleeve is coated with a CsPbBr3 quantum dot film for fixation and sealing.

[0049] In addition, this invention also proposes a method for preparing a multilayer metascintillator with a microcavity structure, the specific steps of which are as follows:

[0050] 1) Prepare 20 ml of CsPbBr3 quantum dot solution and 4 thin zinc oxide sheets with thicknesses of 0.2 mm, 0.2 mm, 0.1 mm and 0.1 mm respectively;

[0051] 2) The thin zinc oxide sheets are sorted. Thin zinc oxide sheet No. 1 is used as the bottom surface with a thickness of 0.2 mm. Thin zinc oxide sheets No. 2, No. 3 and No. 4, which are used as the top surface, have thicknesses of 0.2 mm, 0.1 mm and 0.1 mm, respectively.

[0052] 3) Through micromachining, microcavity flaps 6 are made on the top surface of thin zinc oxide No. 1 and on both sides of thin zinc oxide No. 2, No. 3 and No. 4;

[0053] 4) Place the top surface of thin zinc oxide No. 1 and the bottom surface of thin zinc oxide No. 2 facing upwards, and fill the microcavity lobe 6 with CsPbBr3 quantum dot solution;

[0054] 5) After standing for 3 minutes, add CsPbBr3 quantum dot solution to the local depressions again, and after standing for 10 minutes again, a smooth wet film will form on the surface.

[0055] 6) Align and adhere the top surface of thin zinc oxide sheet No. 1 and the bottom surface of thin zinc oxide sheet No. 2, and then compact and pre-tighten them. Figure 2 As shown;

[0056] 7) Transfer it to a vacuum oven, reduce the pressure inside the oven to 2 Pa, and keep it for 2 hours to accelerate solvent evaporation and thoroughly dry the CsPbBr3 quantum dot solution in the gaps;

[0057] 8) Apply steps 4) to 7) to the top surface of thin zinc oxide No. 2 and the bottom surface of thin zinc oxide No. 3, and the top surface of thin zinc oxide No. 3 and the bottom surface of thin zinc oxide No. 4, until the layering and splicing are completed;

[0058] 9) Fabricate a zinc oxide sleeve with a height of 0.6 mm, an inner diameter of 42.01 mm, and an outer diameter of 50 mm. Coat the inner wall of the sleeve with a CsPbBr3 quantum dot solution. Slide the zinc oxide sleeve over the formed multilayer zinc oxide 1 and allow it to stand until the CsPbBr3 quantum dot solution solidifies and dries.

[0059] 10) Fill the microcavity flap 6 with CsPbBr3 quantum dot solution on the top surface of thin zinc oxide sheet No. 4, then place it in a vacuum oven, reduce the air pressure inside the oven to 2 Pa, and maintain this position for 24 hours to allow the CsPbBr3 quantum dot solution in the gaps to dry completely. This method can accelerate the solidification speed of the quantum dot solution. Drying the quantum dot solution at room temperature and pressure requires a longer time and is easily affected by moisture in the air, thus affecting the control effect.

[0060] 11) A multilayer metascintillator with a microcavity structure was obtained.

[0061] In this embodiment, the process of aligning and bonding the two thin zinc oxide sheets is as follows: Figure 2 As shown, the two surface microcavity lobes 6 have identical cross-sections, and after bonding, they form a complete ellipsoidal microcavity 3. A thin layer of CsPbBr3 quantum dot solution exists on the bonding surface. The typical control unit 7 of the multilayer metascintillator with the microcavity structure is shown in the figure. Figure 4 As shown, the structure includes a control unit substrate 8, a control unit microcavity 9, and a control unit control material 10. This structure is used for preliminary theoretical calculations, and the theoretical calculation results are as follows: Figure 3 As shown. Figure 3 The paper presents the effects of having and not having a microcavity structure, filling the microcavity with CsPbBr3 quantum dot colloid, and vacuum on the control of luminescence. The changes in the emitted light distribution can be clearly observed, indicating that the control is effective.

[0062] Example 2

[0063] This invention discloses a method for preparing a multilayer metascintillator with a microcavity structure, in which vacuum is used instead of control material 4, and vacuum sealant is used for sealing. The specific steps are as follows:

[0064] 1) Prepare four thin zinc oxide sheets with thicknesses of 0.2 mm, 0.2 mm, 0.1 mm, and 0.1 mm, respectively;

[0065] 2) The thin zinc oxide sheets are sorted. Thin zinc oxide sheet No. 1 is used as the bottom surface with a thickness of 0.2 mm. Thin zinc oxide sheets No. 2, No. 3 and No. 4, which are used as the top surface, have thicknesses of 0.2 mm, 0.1 mm and 0.1 mm, respectively.

[0066] 3) Microstructures were fabricated on the top surface of thin zinc oxide No. 1 and on both sides of thin zinc oxide No. 2, No. 3 and No. 4 through micromachining;

[0067] 4) Place the thin zinc oxide sheet inside the vacuum operating chamber;

[0068] 5) Align, attach, and press the thin zinc oxide sheets in sequence to ensure they are firmly in place;

[0069] 6) Apply a dense vacuum sealant to the sides to seal them;

[0070] 7) After standing for 15 minutes and the sealant has dried, slowly increase the air pressure in the operating chamber. After 3 minutes, restore the operating chamber to atmospheric pressure.

[0071] 8) A multilayer metascintillator with a microcavity structure was obtained.

[0072] Example 3

[0073] This invention discloses a method for preparing a multilayer metascintillator with a microcavity structure. The monolayer substrate scintillator 2 is gallium nitride, the control material 4 is nitrogen, and other components are the same as in Example 2. The specific steps of the metascintillator preparation method are as follows:

[0074] Prepare four thin gallium nitride sheets with thicknesses of 0.2 mm, 0.2 mm, 0.1 mm, and 0.1 mm, respectively;

[0075] 2) The thin gallium nitride sheets are sorted. Thin gallium nitride sheet No. 1 is used as the bottom surface with a thickness of 0.2 mm. Thin gallium nitride sheets No. 2, No. 3 and No. 4, which are used as the top surface, have thicknesses of 0.2 mm, 0.1 mm and 0.1 mm, respectively.

[0076] 3) Microstructures were fabricated on the top surface of thin gallium nitride layer 1 and on both sides of thin gallium nitride layers 2, 3 and 4 through micromachining;

[0077] 4) Place the thin gallium nitride sheet in a sealed operating chamber, evacuate it, and then fill it with nitrogen gas at a pressure slightly less than one atmosphere.

[0078] 5) Align, attach, and press the thin gallium nitride sheets in sequence;

[0079] 6) Apply a dense vacuum sealant to the sides to seal them;

[0080] 7) After standing for 15 minutes and the sealant has dried, connect the operating chamber to the atmosphere;

[0081] 8) A multilayer metascintillator with a microcavity structure was obtained.

[0082] The calculation results of this invention for typical working conditions and combinations are as follows: Figure 3 As shown. Comparison Figure 3 (a) When there is no microcavity structure, the light emission of the crystal is uniformly distributed in all positions and directions, using CsPbBr3 quantum dot solution. Figure 3 (b) and vacuum Figure 3(c) The microcavity structure as the content significantly alters the luminescence distribution and intensity of the substrate scintillator.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present invention.

Claims

1. A multilayer metascintillator with a microcavity structure, characterized in that: It includes a substrate scintillator (1) and a plurality of microcavities (3) disposed inside the substrate scintillator (1); The substrate scintillator (1) includes multiple monolayer substrate scintillators (2) stacked sequentially; the microcavity (3) is formed by complementary microcavity lobes (6) arranged on the bonding surface of two adjacent monolayer substrate scintillators (2); the microcavity lobes (6) have a scale on the order of nm to μm. The microcavity (3) and the interlayer gaps are either in a vacuum or filled with a control material (4). The multi-layer single-layer substrate scintillator (2) is sealed.

2. The multilayer metascintillator with a microcavity structure according to claim 1, characterized in that: The substrate scintillator (1) includes zinc oxide, barium fluoride, or a plastic scintillator.

3. The multilayer metascintillator with a microcavity structure according to claim 2, characterized in that: The single-layer substrate scintillator (2) has a nanosecond-level time response, a thickness of 20μm-200μm, a diameter of 5mm-50mm, and a quantity of 2-20 pieces.

4. The multilayer metascintillator with a microcavity structure according to claim 3, characterized in that: The microcavity (3) has a scale on the order of nm to μm and its shape includes spheres, ellipsoids, cylinders or cones.

5. A multilayer metascintillator with a microcavity structure according to claim 4, characterized in that: The control material (4) includes an inert gas or a perovskite quantum dot solution.

6. The multilayer metascintillator with a microcavity structure according to claim 5, characterized in that: The multiple single-layer substrate scintillators (2) are sealed by homogeneous sleeves (5) or vacuum sealant.

7. A multilayer metascintillator with a microcavity structure according to claim 6, characterized in that: The control material (4) is a perovskite quantum dot solution, and multiple microcavity lobes (6) filled with perovskite quantum dot solution are set on the upper surface of the top layer monolayer substrate scintillator (2).

8. A method for preparing a multilayer metascintillator with a microcavity structure according to any one of claims 1-7, characterized in that, Includes the following steps: Step 1: Sort and number the multiple single-layer substrate scintillators (2) in advance, and the single-layer substrate scintillator (2) to be used as the bottom surface is number 1; Step 2: Microcavity flaps (6) are fabricated on one or both sides of each monolayer substrate scintillator (2) by micromachining. Step 3: Fill the microcavity lobe (6) with the control material (4) on the bonding surface of two adjacent numbered monolayer substrate scintillators (2), and form a wet film on their respective surfaces; Step 4: After the wet film has become gel-like, align and attach the two adjacent single-layer substrate scintillators (2) and press them together to pre-tighten them. Step 5: After drying, follow the steps 3-4 to complete the splicing of all numbered single-layer substrate scintillators (2) to form a multi-layer substrate scintillator (1). Step 6: Seal the side of the substrate scintillator (1) and fill the gap with control material (4) for sealing and fixing, to obtain a multilayer metascintillator with a microcavity structure.

9. A method for preparing a multilayer metascintillator with a microcavity structure according to any one of claims 1-7, characterized in that, Includes the following steps: Step 1: Sort and number the multiple single-layer substrate scintillators (2) in advance, and the single-layer substrate scintillator (2) to be used as the bottom surface is number 1; Step 2: Microcavity flaps (6) are fabricated on one or both sides of each monolayer substrate scintillator (2) by micromachining. Step 3: Place the single-layer substrate scintillator (2) in the vacuum operating chamber, align, attach and compact it in sequence to form a multi-layer substrate scintillator (1). Step 4: Apply a dense vacuum sealant to the side of the substrate scintillator (1) for sealing; Step 5: After the sealant has dried and set, slowly increase the pressure in the vacuum operating chamber and then restore the vacuum operating chamber to atmospheric pressure to obtain a multilayer metascintillator with a microcavity structure.

10. A method for preparing a multilayer metascintillator with a microcavity structure according to any one of claims 1-7, characterized in that, Includes the following steps: Step 1: Sort and number the multiple single-layer substrate scintillators (2) in advance, and the single-layer substrate scintillator (2) to be used as the bottom surface is number 1; Step 2: Microcavity flaps (6) are fabricated on one or both sides of each monolayer substrate scintillator (2) by micromachining. Step 3: Place the single-layer substrate scintillator (2) in the sealed operating chamber, evacuate and fill with nitrogen, and align, attach and press the multiple single-layer substrate scintillators (2) in sequence to form a multi-layer substrate scintillator (1). Step 4: Apply a dense vacuum sealant to the side of the substrate scintillator (1) for sealing; Step 5: After the sealant has dried and solidified, connect the sealed operating chamber to the atmosphere to obtain a multilayer metascintillator with a microcavity structure.

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