L-shaped spaceborne plastic scintillator detector and preparation method thereof

Abstract

The application relates to an L-shaped spaceborne plastic scintillator detector and a preparation method thereof, which comprises a first bearing component and a second bearing component, which are vertically assembled together in an L shape; a plastic scintillator detection unit, which comprises a plastic scintillator module installed on the first bearing component, and a plurality of optical fiber embedding grooves capable of accommodating single optical fibers are arranged on the plastic scintillator module in parallel; an optical fiber bending support unit, which is assembled on the first bearing component and located at the connecting end of the first bearing component and the second bearing component, is arranged perpendicularly to the optical fiber embedding grooves and used as a bending track and a support structure during optical fiber bending; a PMT coupling unit and an electronic unit, which are assembled on the second bearing component, are connected with the optical fibers, used for converting optical signals into electrical signals, and connected with the PMT coupling unit, used for processing and reading out the electrical signals. The detector can realize the overlapping arrangement of the plastic scintillator detection unit and realize the 90-degree bending of the optical fiber transmission path.

Description

Technical Field

[0001] This invention relates to an L-shaped spaceborne plastic scintillator and its fabrication method, belonging to the field of space particle detection technology. Background Technology

[0002] The primary scientific objectives of the Very Large Area Gamma-ray Space Telescope (VLAST) are to search for evidence of dark matter candidate particles and to monitor gamma-ray radiation from astronomical events such as gravitational waves. The outermost anti-coincidence detector of VLAST distinguishes photons from charged particles. Its principle is that plastic scintillator elements on the surface of the anti-coincidence detector detect low-energy photons. The low-energy photon signals detected by the plastic scintillator elements are transmitted through optical fibers. These signals are then converted into electrical signals by photomultiplier tubes (PMTs), which then output the signals for analysis. Traditional optical fiber transmission involves bundling the fibers and coating them with materials such as glass fiber and polyester to ensure both transmission efficiency and resilience and reliability along the transmission path. However, spacecraft detectors require the optical fibers to be uniformly distributed across the plastic scintillator elements to guarantee detection efficiency. This makes it difficult to bundle the fibers at the plastic scintillator interface, and also highlights the urgent need to address the stability and reliability of single optical fibers under the complex mechanical environment of space launch. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides an L-shaped spaceborne plastic scintillator, which distributes the detection unit and readout unit at a 90° angle to save lateral space, enabling overlapping arrangement of the plastic scintillator detection units and achieving a 90° bend in the optical fiber transmission path.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: An L-type spaceborne plastic scintillator includes: The first load-bearing component and the second load-bearing component are assembled together in an L-shape perpendicularly. The plastic scintillator detection unit includes a plastic scintillator module installed on the first carrier component, wherein the plastic scintillator module has several parallelly arranged fiber optic embedded slots that can accommodate a single optical fiber. An optical fiber bending support unit is assembled on the first bearing component and located at the connection end between the first bearing component and the second bearing component. The optical fiber bending support unit is arranged perpendicularly to the embedded groove in the optical fiber and is used as the bending trajectory and support structure when the optical fiber is bent. The PMT coupling unit and the electronics unit are assembled on the second carrier component. The PMT coupling unit is connected to the optical fiber and is used to convert optical signals into electrical signals. The electronics unit is connected to the PMT coupling unit and is responsible for the processing and readout conversion of electrical signals.

[0005] Preferably, the L-type spaceborne plastic scintillator module includes an upper large plastic scintillator and several lower overlapping small plastic scintillators. Several fiber optic embedded slots are formed on one side of the large plastic scintillator and one side of the small plastic scintillators. The small plastic scintillators are divided into upper and lower layers and the upper and lower layers are partially stacked together to form a stepped structure.

[0006] Preferably, in the L-shaped spaceborne plastic scintillator described above, the embedded groove in the optical fiber is an inverted Ω-shaped groove.

[0007] Preferably, in the L-shaped spaceborne plastic scintillator described above, the plastic scintillator module is positioned on the first supporting component by a number of positioning blocks, and its four corners are respectively fixed to the first supporting component by positioning corner posts.

[0008] Preferably, the L-shaped spaceborne plastic scintillator includes a first-layer fiber bending support structure and a second-layer fiber bending support structure. The first-layer fiber bending support structure is provided with a plurality of fiber bundle slots. The first-layer fiber bending support structure is used to support the bending of the fiber of the lower overlapping small plastic scintillator, and the second-layer fiber bending support structure is used to support the bending of the fiber of the upper large plastic scintillator.

[0009] The L-shaped spaceborne plastic scintillator preferably further includes a bundled fiber beam disposed on the second support component and located at the connection end between the first support component and the second support component. The bundled fiber beam is provided with a bundled hole to accommodate the bundled fiber beam.

[0010] Preferably, the L-shaped spaceborne plastic scintillator includes a first PMT mounting beam and a second PMT mounting beam, both of which are mounted on the second support component. A plurality of PMTs are assembled on the first PMT mounting beam and the second PMT mounting beam.

[0011] Preferably, in the L-shaped spaceborne plastic scintillator, the electronics unit includes an electronics chassis, on which a FEE high-voltage integrated board and a cable tie are installed.

[0012] A second aspect of this invention provides a method for fabricating an L-shaped spaceborne plastic scintillator, comprising the following steps: The first load-bearing component and the second load-bearing component are fastened together using screws; The first layer of optical fiber bending support structure is installed on the first bearing component, and then a plurality of small plastic scintillators are overlapped and installed on the first bearing component and positioned by the positioning corner posts and the positioning blocks; The optical fiber is installed and glued inside the small plastic scintillator. The optical fiber is bundled as required and attached to the surface of the first layer optical fiber bending support structure. Then it is placed in an insulated box for a certain period of time to achieve the thermoforming of the lower layer of small plastic scintillator optical fiber. After the device cools down, it is taken out and the second layer of optical fiber bending support structure and the large plastic scintillator are installed. Then the device is placed in an insulated box for a certain period of time to achieve the thermoforming of the upper layer of large plastic scintillator optical fiber. After the optical fiber is shaped, the plastic scintillator detection unit is crimped and fixed; finally, the bundled optical fiber beam, the PMT coupling unit, and the electronics unit are all installed on the second support component.

[0013] The present invention has the following advantages due to the adoption of the above technical solutions: 1. In order to make the detector structure as compact as possible and to provide technical verification for future larger detectors, the present invention distributes the plastic scintillator detection unit, PMT coupling unit and electronic unit at 90° to save lateral space.

[0014] 2. To reduce the detection dead zone and increase the detection efficiency, the plastic scintillator detection unit consists of a large 400*400 plastic scintillator at the top and small plastic scintillators arranged in overlapping patterns at the bottom. The surface of the plastic scintillator is engraved with embedded grooves in the optical fiber according to the detection requirements. To ensure that the optical fiber is easy to embed and not easy to fall off, the cross-sectional shape of the embedded groove in the optical fiber is an inverted Ω groove.

[0015] 3. The present invention is an anti-coincidence detector that can realize the overlapping arrangement of plastic scintillator detection units and can realize a 90° bend in the optical fiber transmission path. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the plastic scintillator provided by the present invention; Figure 2 This is a schematic diagram of the internal composition of the plastic scintillator provided by the present invention; Figure 3 This is a schematic diagram of the assembly structure of the plastic scintillator detection unit provided by the present invention; Figure 4a and Figure 4b This is a schematic diagram of plastic flashover provided by the present invention; Figure 5 This is a schematic diagram of the cross-section of the grooved surface of the plastic flash provided by the present invention; Figure 6 A schematic diagram of the fiber optic bundle beam provided by the present invention; Figure 7 A schematic diagram of the PMT and its support provided by the present invention; Figure 8 A schematic diagram of the electronic chassis provided for this invention; Figure 9A schematic diagram of a single-layer optical fiber bending support structure provided by the present invention; Figure 10 This is a schematic diagram of the two-layer optical fiber bending support structure provided by the present invention; Figure 11 This is a schematic diagram of the cross-section of the two-layer optical fiber bending support provided by the present invention; Figure 12 The auxiliary support rib structure provided by the present invention; The attached figures are labeled as follows: 1-Plastic scintillator detection unit; 2-Fiber optic bending support unit; 3-Buried fiber optic beam; 4-PMT coupling unit; 5-Electronics unit; 6-Second honeycomb panel; 7-Auxiliary support rib; 101-Plastic flash module; 102-First honeycomb panel; 103-Positioning block; 104-Positioning corner post; 1011 - First small plastic glitter; 1012 - Second small plastic glitter; 1013 - Third small plastic glitter; 1014 - Fourth small plastic glitter; 1015 - Large plastic glitter; 201 - First layer fiber bending support structure; 2011 - Fiber optic bundle slot; 202 - Second layer fiber bending support structure; 301 - Fiber optic bracket; 302 - Fiber optic clamp; 401 - First PMT mounting beam; 402 - Second PMT mounting beam; 403 - PMT; 501 - Electronic interface; 502 - FEE high voltage integrated board; 503 - Electronic chassis; 504 - Cable tie; 505 - High voltage interface. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention are described clearly and completely below. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0018] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," "third," "fourth," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect.

[0019] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "above," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure.

[0020] Traditional fiber optic transmission involves bundling optical fibers and sheathing them with materials such as glass fiber and polyester. This ensures both transmission efficiency and resilience and reliability along the transmission path. However, the optical fibers in space probes must be uniformly distributed across the plastic scintillator (PSS) detection unit to guarantee detection efficiency. This makes it difficult to bundle the fibers at the PSS interface, and also makes it crucial to address the stability and reliability of a single fiber under the complex mechanical environment of space launch.

[0021] Based on the above-mentioned technical problems, the present invention provides an L-shaped spaceborne plastic scintillator, which distributes the detection unit and the readout unit at 90° to save lateral space, enables the plastic scintillator detection unit to be overlapped, and enables the optical fiber transmission path to bend 90°.

[0022] like Figure 1 , 2 As shown in Figure 3, the L-type spaceborne plastic scintillator involved in this invention includes: The first and second carrier components are assembled vertically together in an L-shape. The plastic scintillator (PSA) detection unit 1 is used to receive photons and charged particles, including a PSA module 101 installed on the first carrier component. The PSA module 101 has several parallel-arranged fiber optic embedded slots that can accommodate a single optical fiber. The optical fiber bending support unit 2 is assembled on the first carrier component and located at the connection end between the first and second carrier components. The optical fiber bending support unit 2 is arranged perpendicularly to the fiber optic embedded slots and serves as a bending track and support structure when the optical fiber bends. The PMT coupling unit 4 and the electronics unit 5 are assembled on the second carrier component. The PMT coupling unit 4 is connected to the optical fiber and is used to convert optical signals into electrical signals. The electronics unit 5 is connected to the PMT coupling unit 4 and is responsible for the processing and readout conversion of electrical signals.

[0023] Furthermore, the first load-bearing component is preferably a honeycomb panel, namely the first honeycomb panel 102, and the second load-bearing component is also preferably a honeycomb panel, namely the second honeycomb panel 6.

[0024] Furthermore, such as Figure 4a , 4b As shown, the plastic scintillator module 101 includes an upper large plastic scintillator 1015 and several lower overlapping small plastic scintillators (e.g., four small plastic scintillators: a first small plastic scintillator 1011, a second small plastic scintillator 1012, a third small plastic scintillator 1013, and a fourth small plastic scintillator 1014). Several fiber optic embedded slots are formed on one side of the large plastic scintillator 1015 and one side of each small plastic scintillator. The overlapping small plastic scintillators are divided into upper and lower groups, and the upper and lower groups are partially stacked together to form a stepped structure. Furthermore, the side of the upper small plastic scintillator with the fiber optic embedded slot corresponds to the side of the lower small plastic scintillator with the fiber optic embedded slot. Preferably, as shown... Figure 5 As shown, the embedded groove in the optical fiber is an inverted Ω-shaped groove. To reduce the detection dead zone and increase detection efficiency, the plastic scintillator detection unit 1 of this invention consists of a large plastic scintillator (400mm*400mm) at the top and overlapping small plastic scintillators at the bottom. The surfaces of the plastic scintillators are all engraved with embedded grooves in the optical fiber according to the detection requirements. To ensure that the optical fiber is easy to embed and not easily detached, the cross-sectional shape of the embedded groove is an inverted Ω-shaped groove. The four small plastic scintillators are overlapped to reduce the edge dead zone and improve detection efficiency.

[0025] In a preferred embodiment of the present invention, such as Figure 3 As shown, the plastic flash module 101 is positioned on the first honeycomb plate 102 by several positioning blocks 103, and its four corners are fixed on the second honeycomb plate 6 by positioning corner posts 104. The positioning corner posts 104 serve both as positioning blocks for the plastic flash module and as the main load-bearing structure of the large plastic flash module 1015.

[0026] In a preferred embodiment of the present invention, such as Figure 9 , 10As shown in Figure 11, the optical fiber bending support unit 2 includes a first-layer optical fiber bending support structure 201 and a second-layer optical fiber bending support structure 202. The first-layer optical fiber bending support structure 201 is provided with a plurality of optical fiber bundle slots 2011. The first-layer optical fiber bending support structure 201 is used to support the bending of the lower layer overlapping small plastic scintillator, and the second-layer optical fiber bending support structure 202 is used to support the bending of the upper layer large plastic scintillator 1015.

[0027] Furthermore, such as Figure 6 As shown, the plastic scintillator of the present invention also includes a bundled fiber beam 3, which is disposed on the second support component and located at the connection end between the first cellular plate 102 and the second cellular plate 6. The bundled fiber beam 3 is provided with a bundled hole for accommodating the bundled fiber to pass through.

[0028] Furthermore, such as Figure 7 As shown, the PMT coupling unit 4 includes a first PMT mounting beam 401 and a second PMT mounting beam 402, both of which are mounted on the second bearing component. A plurality of PMTs 403 are assembled on the first PMT mounting beam 401 and the second PMT mounting beam 402.

[0029] Furthermore, such as Figure 8 As shown, the electronics unit 5 includes an electronics chassis 503, on which a FEE high-voltage integrated board 502 and a cable tie 504 are mounted. The left end of the electronics chassis 503 has an electronics interface 501, and the right end has a high-voltage interface 505.

[0030] Furthermore, such as Figure 12 As shown, an auxiliary support rib 7 is also provided between the first honeycomb panel 102 and the second honeycomb panel 6 to enhance the overall structural rigidity.

[0031] like Figure 2 , 3 As shown, the present invention also provides a method for fabricating a plastic scintillator, comprising the following steps: Step 1: First, fasten the first honeycomb panel 102 and the second honeycomb panel 6 together with screws; Step 2: First, install the first layer of fiber optic bending support structure 201 onto the first honeycomb panel 102; then install the four positioning corner posts 104 onto the first honeycomb panel 102; glue two layers of 0.5mm thick shock-absorbing foam onto the mounting surfaces of the first small plastic flash 1011 and the second small plastic flash 1012; place the first small plastic flash 1011 and the second small plastic flash 1012 with the slotted surfaces facing down in their corresponding positions and install the positioning blocks 103; then place the third small plastic flash 1013 and the fourth small plastic flash 1014 with the slotted surfaces facing up in their corresponding positions and install the corresponding positioning blocks 103.

[0032] Step 3: Insert a single optical fiber into the first small plastic scintillator 1011, the second small plastic scintillator 1012, the third small plastic scintillator 1013, and the fourth small plastic scintillator 1014, and bundle the optical fibers as required (the fibers of the first small plastic scintillator 1011 and the second small plastic scintillator 1012 are bundled together; the fibers of the third small plastic scintillator 1013 and the fourth small plastic scintillator 1014 are bundled together, and the bundles are alternately bundled), and attach them to the surface of the first layer optical fiber bending support structure 201. Ensure that the path of each bundled optical fiber passes through the corresponding optical fiber bundling slot 2011 of the first layer optical fiber bending support structure 201. Use aviation black tape to gradually attach the bundled optical fibers from the interface between the plastic scintillator and the optical fiber bending support unit 2, following the structural curvature of the optical fiber bending support unit 2, and gradually attach them to the surface of the optical fiber bending support unit 2 to achieve the pre-shaped shape of the optical fibers, so as to ensure that the bundled optical fibers pass through the bundling holes of the bundled optical fiber beam 3. Then install the optical fiber clamping block 302 to keep the optical fibers stable. The above-mentioned installation structure was placed in a 70-degree Celsius insulated box for thermoforming for 3 hours, followed by natural heat preservation for 3 hours. This allowed the overlapping small thermoplastic readout optical fibers to take shape.

[0033] Step 4: After removing the above-mentioned installation structure from the insulation box and allowing it to cool naturally, install the second layer of fiber optic bending support structure 202. The second layer of fiber optic bending support structure 202 and the first layer of fiber optic bending support structure 201 are fastened together with screws in the middle to maintain their integrity. The installation and shaping of the upper layer large plastic scintillator 1015 is similar to that of the overlapping small plastic scintillators. In particular, the rear half of the large plastic scintillator 1015 is supported on the third small plastic scintillator 1013 and the fourth small plastic scintillator 1014. Therefore, before installation, a layer of shock-absorbing foam needs to be pasted between the third small plastic scintillator 1013, the fourth small plastic scintillator 1014 and the large plastic scintillator 1015. The thermal insulation and thermoforming process of the large plastic scintillator 1015 is similar to that of the small plastic scintillators and will not be described in detail here.

[0034] Step 5: After fiber optic shaping, press-fit and fix the plastic scintillator detection unit 1; finally, install the bundled fiber beam 3, PMT coupling unit 4, and electronics unit 5 onto the second honeycomb board 6. Specifically, adjust the position of the corresponding PMT4 according to the fiber optic shaping path and install it. Install the electrically assembled FEE high-voltage integrated board 502 into the electronics chassis 503, such as... Figure 8 As shown, the electronics chassis 503 has an electronics interface 501 on the left end and a high-voltage interface 505 on the right end. 504 is a cable tie for binding long cables. The assembled electronics chassis 503 is then mounted onto the second honeycomb panel 6. The cables from the PMT4 are welded to the FEE high-voltage integrated board 502. The chassis cover is then installed, completing the installation. Finally, auxiliary support ribs 7 are installed to enhance the overall structural rigidity.

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not 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 of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An L-shaped spaceborne plastic scintillator, characterized in that, include: The first load-bearing component and the second load-bearing component are assembled together in an L-shape perpendicularly. Plastic scintillator detection unit (1) includes a plastic scintillator module (101) installed on the first carrier component. The plastic scintillator module (101) has several parallel-arranged fiber optic embedded slots that can accommodate a single optical fiber. The optical fiber bending support unit (2) is assembled on the first bearing component and located at the connection between the first bearing component and the second bearing component. The optical fiber bending support unit (2) is arranged perpendicularly to the embedded groove in the optical fiber and is used as a bending track and support structure when the optical fiber is bent. The PMT coupling unit (4) and the electronics unit (5) are assembled on the second carrier component. The PMT coupling unit (4) is connected to the optical fiber and is used to convert optical signals into electrical signals. The electronics unit (5) is connected to the PMT coupling unit (4) and is responsible for the processing and readout conversion of electrical signals.

2. The L-type spaceborne plastic scintillator according to claim 1, characterized in that, The plastic scintillator module (101) includes an upper large plastic scintillator (1015) and several lower small plastic scintillators arranged in an overlapping manner. Several fiber optic embedded grooves are opened on one side of the large plastic scintillator (1015) and one side of the small plastic scintillators. The several small plastic scintillators are divided into upper and lower layers and the upper and lower layers are partially stacked together to form a stepped structure.

3. The L-type spaceborne plastic scintillator according to claim 2, characterized in that, The embedded groove in the optical fiber is an inverted Ω groove.

4. The L-type spaceborne plastic scintillator according to claim 3, characterized in that, The plastic flash module (101) is positioned on the first bearing component by a number of positioning blocks (103), and its four corners are fixed on the first bearing component by positioning corner posts (104).

5. The L-type spaceborne plastic scintillator according to claim 4, characterized in that, The fiber bending support unit (2) includes a first layer fiber bending support structure (201) and a second layer fiber bending support structure (202). The first layer fiber bending support structure (201) is provided with a plurality of fiber bundle slots (2011). The first layer fiber bending support structure (201) is used to support the bending of the fiber of the small plastic scintillator overlapping in the lower layer, and the second layer fiber bending support structure (202) is used to support the bending of the fiber of the large plastic scintillator (1015) in the upper layer.

6. The L-type spaceborne plastic scintillator according to claim 5, characterized in that... It also includes a bundled fiber beam (3), which is disposed on the second bearing component and located at the connection end between the first bearing component and the second bearing component. The bundled fiber beam (3) is provided with a bundled hole to accommodate the bundled fiber passing through.

7. The L-type spaceborne plastic scintillator according to claim 6, characterized in that, The PMT coupling unit (4) includes a first PMT mounting beam (401) and a second PMT mounting beam (402), both of which are mounted on the second bearing component. A plurality of PMTs (403) are assembled on the first PMT mounting beam (401) and the second PMT mounting beam (402).

8. The L-type spaceborne plastic scintillator according to claim 7, characterized in that, The electronics unit (5) includes an electronics chassis (503), on which a FEE high voltage integrated board (502) and a wire tie (504) are provided.

9. A method for fabricating an L-shaped spaceborne plastic scintillator according to claim 8, characterized in that, Includes the following steps: The first load-bearing component and the second load-bearing component are fastened together using screws; The first layer of optical fiber bending support structure (201) is installed on the first bearing component, and then a plurality of small plastic scintillators are overlapped and installed on the first bearing component and positioned by the positioning corner post (104) and the positioning block (103); The optical fiber is installed and glued inside the small plastic scintillator. The optical fiber is bundled as required and attached to the surface of the first layer optical fiber bending support structure (201). Then it is placed in an insulated box for a certain period of time to achieve the thermoforming of the lower layer of small plastic scintillator optical fiber. After the device is cooled, the second layer of optical fiber bending support structure (202) and the large plastic scintillator (1015) are removed and installed. The device is then placed in an insulated box for a certain period of time to achieve the thermoforming of the upper layer of large plastic scintillator (1015) optical fiber. After the optical fiber is shaped, the plastic scintillator detection unit (1) is crimped and fixed; finally, the bundled optical fiber beam (3), the PMT coupling unit (4), and the electronics unit (5) are all installed on the second bearing component.

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