A multi-stage nested neutron detector front-end shielding device

Abstract

The application relates to a multi-stage nested neutron detector front-end shielding device, and belongs to the technical field of neutron scattering and nondestructive testing. The shielding device comprises a multi-stage telescopic shielding structure and a shielding bin which are in communication, and a cantilever driving mechanism; the multi-stage telescopic shielding structure has a plurality of shielding sleeves which are sequentially and slidably connected and in communication; a preceding shielding sleeve is sleeved on the outer periphery of a following shielding sleeve; a first annular protrusion is arranged on the inner wall of the preceding shielding sleeve close to the following shielding sleeve; a second annular protrusion is arranged on the outer wall of the following shielding sleeve close to the preceding shielding sleeve; the first and second annular protrusions are overlapped in a first horizontal direction projection; the cantilever driving mechanism is located at the top of the shielding bin and comprises a cantilever and a driving module which drives the multi-stage telescopic shielding structure to telescopically extend and retract; and the end of the cantilever away from the shielding bin is provided with a precision adjusting platform. The device can realize large-stroke telescopic avoidance of a sample, effectively suppresses stray neutron leakage, and ensures the positioning accuracy of the shielding device and an optical path.

Description

Technical Field

[0001] This application relates to the fields of neutron scattering technology and non-destructive testing technology, and in particular to a multi-level nested neutron detector front-end shielding device. Background Technology

[0002] Neutron diffraction stress analysis is the only non-destructive method for measuring the three-dimensional residual stress inside engineering components, and it has irreplaceable application value in key fields such as aerospace, nuclear power equipment, and high-end manufacturing. In neutron diffraction stress measurement experiments, the neutron detector must be protected from interference from high-intensity stray neutrons to ensure the signal-to-noise ratio and measurement accuracy. Simultaneously, to obtain stress data from different directions and locations of the component, the sample needs to adjust its attitude under the drive of a multi-degree-of-freedom rotation mechanism. This requires the shielding device at the front end of the neutron detector to have flexible telescopic and obstacle-avoidance capabilities.

[0003] However, existing detector front-end shielding devices used in neutron diffraction stress analysis spectrometers generally face three major challenges: First, spatial interference is significant, and fixed shielding devices are prone to collisions with rotating samples. If they are moved away from the sample to avoid collisions, the spatial resolution and data accuracy will be further reduced. Second, neutron leakage is difficult to solve, leading to a deterioration in the signal-to-noise ratio. Third, the positioning accuracy of the neutron detector front-end shielding device and the optical path is difficult to guarantee.

[0004] Therefore, there is a need for a neutron detector front-end shielding device that can simultaneously solve the problems of space interference, neutron leakage, and positioning accuracy. Summary of the Invention

[0005] The purpose of this application is to provide a multi-level nested neutron detector front-end shielding device. This device can effectively suppress stray neutron leakage during the large-stroke extension and retraction to avoid samples, while ensuring the positioning accuracy of the neutron detector front-end shielding device and the optical path, and providing reliable shielding protection for the neutron detector. It has the advantages of stable structure, convenient operation and strong compatibility.

[0006] This application provides a multi-level nested neutron detector front-end shielding device, comprising: a multi-level telescopic shielding structure, a shielding chamber, and a cantilever drive mechanism; the multi-level telescopic shielding structure has multiple shielding sleeves that are sequentially slidably connected and interconnected along a first horizontal direction; along the first horizontal direction, the preceding shielding sleeve is fitted onto the outer periphery of the following shielding sleeve, and a first annular protrusion surrounding the first horizontal direction is provided on the inner wall of the preceding shielding sleeve near the following shielding sleeve, and a second annular protrusion surrounding the first horizontal direction is provided on the outer wall of the following shielding sleeve near the preceding shielding sleeve, the first annular protrusion and the second annular protrusion being positioned in the first horizontal direction. The shadows overlap, and the first and second annular protrusions can interlock with each other; the central axes of each shielding sleeve coincide; the inner cavity of the shielding chamber is used to place the neutron detector, and the shielding chamber is fixedly connected to and communicates with the first shielding sleeve along the first horizontal direction; the cantilever drive mechanism is set on the top of the shielding chamber, and the cantilever drive mechanism includes a cantilever and a drive module, the drive module is used to drive the multi-stage telescopic shielding structure to extend and retract; the cantilever extends along the first horizontal direction, and a precision adjustment platform is set at the end of the cantilever away from the shielding chamber and connected to the end of the multi-stage telescopic shielding structure away from the shielding chamber, the precision adjustment platform is used to adjust the position of the center of the port of the multi-stage telescopic shielding structure away from the shielding chamber.

[0007] The multi-level nested neutron detector front-end shielding device provided in this application provides sufficient extension and retraction stroke by setting up shielding sleeves that are sequentially slidably connected, interconnected, and nested. A cantilever drive mechanism at the top of the shielding chamber drives the extension and retraction of the multi-level telescopic shielding structure, avoiding spatial obstacles below and providing ample space for multi-degree-of-freedom rotation of the sample, thus solving spatial interference problems and ensuring the spatial resolution and data accuracy obtained by the neutron detector. By setting a first and second annular protrusion with a specific structure to form a non-straight-slit radiation attenuation channel, the multi-level telescopic shielding structure remains in a sealed shielding state during extension and retraction, achieving dynamic sealing shielding and effectively preventing neutron leakage. A precision adjustment stage is used to precisely adjust the position of the port center of the multi-level telescopic shielding structure furthest from the shielding chamber, ensuring the positioning accuracy of the neutron detector front-end shielding device and the optical path. Therefore, the multi-level nested neutron detector front-end shielding device provided in this application can effectively suppress stray neutron leakage while achieving large-stroke extension and retraction to avoid samples, ensuring the positioning accuracy of the neutron detector front-end shielding device and the optical path, providing reliable shielding protection for the neutron detector, and has advantages such as structural stability, convenient operation, and strong compatibility.

[0008] In an optional embodiment of this application, in the multi-level telescopic shielding structure, two adjacent shielding sleeves are slidably connected by a first slide rail extending along a first horizontal direction.

[0009] In the above technical solution, by setting the first slide rail, it is beneficial to ensure the smooth and stable telescopic movement of the entire multi-level telescopic shielding structure.

[0010] In an optional embodiment of this application, along the first horizontal direction, a first slide rail is embedded in the inner wall of the first shielding sleeve, and the second shielding sleeve is slidably connected to the first slide rail on the first shielding sleeve through a rolling connector, which is engaged in the first slide rail.

[0011] In the above technical solution, the combination of rolling friction and embedding methods can reduce the size of the splicing gaps and provide precise guidance and positioning, while also forming a self-supporting structure to distribute the weight, reduce the expansion and contraction resistance of the entire multi-level telescopic shielding structure, and ensure the smooth and stable expansion and contraction of the entire multi-level telescopic shielding structure.

[0012] In an optional embodiment of this application, the shielding chamber is a square hollow cavity structure, which is formed by splicing multiple shielding plates, and the gap between any two adjacent shielding plates is a non-through gap.

[0013] The above technical solution helps to avoid neutron leakage in the shielding chamber, thereby ensuring the signal-to-noise ratio and measurement accuracy of the neutron detector signal.

[0014] In an optional embodiment of this application, the gap between any two adjacent shielding plates is a Z-shaped gap.

[0015] The above technical solution can effectively avoid neutron leakage in the shielding chamber, thereby ensuring the signal-to-noise ratio and measurement accuracy of the neutron detector signal.

[0016] In an optional embodiment of this application, a non-through-hole is provided on the shielding plate of the shielding chamber that is far from the multi-level telescopic shielding structure.

[0017] In the above technical solution, the non-through-hole can serve as a cable channel for the neutron detector, which helps to ensure that the cable passes through while avoiding stray neutron leakage.

[0018] In an optional embodiment of this application, the shielding plate of the shielding chamber along the second horizontal direction is a detachable shielding plate; or / and, the shielding plate of the shielding chamber along the second horizontal direction is hinged to the shielding plate of the shielding chamber away from the multi-stage telescopic shielding structure; wherein, the second horizontal direction is perpendicular to the first horizontal direction.

[0019] The above technical solution facilitates the installation, debugging, and maintenance of the neutron detector.

[0020] In an optional embodiment of this application, a support plate is fixedly connected to the top of the shielding chamber, the drive module is fixed to the support plate, and a U-shaped adjustment hole is provided at the bottom of the drive module. The drive module is connected to the support plate through a fixing member that extends into the U-shaped adjustment hole, and the fixing member is configured to selectively move in a second horizontal direction within the U-shaped adjustment hole; wherein, the second horizontal direction is perpendicular to the first horizontal direction.

[0021] In the above technical solution, it is easy to realize the initial centering adjustment of the drive module to ensure that the motion trajectory of the drive module is parallel to the central axis of the multi-level telescopic shielding structure.

[0022] In an optional embodiment of this application, the cantilever and the precision adjustment table are connected by a connecting plate. The precision adjustment table is configured to move relative to the connecting plate in a height direction and a second horizontal direction. The second horizontal direction is perpendicular to the first horizontal direction. The precision adjustment table has a first limiting member and a second limiting member. The first limiting member is configured to selectively restrict the movement of the precision adjustment table in the height direction, and the second limiting member is configured to selectively restrict the movement of the precision adjustment table in the second horizontal direction.

[0023] In the above technical solution, two-dimensional displacement adjustment of the precision adjustment stage can be realized. The first and second limiting components enable the precision adjustment stage to have a locking function, thereby compensating for the deflection deformation of the cantilever caused by gravity and changes in extension length, and thus ensuring the positioning accuracy of the neutron detector front-end shielding device and the optical path.

[0024] In an optional embodiment of this application, the cantilever drive mechanism further includes a second slide rail extending along a first horizontal direction, the shielding sleeve being slidably connected to the second slide rail via a bracket, and the drive module being used to drive the bracket to move along the extension direction of the second slide rail.

[0025] In the above technical solution, the bracket can bear the weight of the shielding sleeve to distribute the load, which is beneficial to improving the structural rigidity and the stability of telescopic movement. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 A schematic diagram of the multi-level nested neutron detector front-end shielding device provided in this application.

[0028] Figure 2 An exploded view of the multi-stage telescopic shielding structure provided in this application.

[0029] Figure 3 This is a cross-sectional view of the multi-level telescopic shielding structure provided in this application.

[0030] Figure 4 This is a structural schematic diagram of the cantilever drive mechanism provided in this application.

[0031] Figure 5 for Figure 1 A magnified view of point M in the middle.

[0032] Icons: A - First horizontal direction; B - Second horizontal direction; 110 - Multi-level telescopic shielding structure; 111 - Shielding sleeve; 112 - First annular protrusion; 113 - Second annular protrusion; 114 - First slide rail; 115 - Shielding block; 120 - Shielding compartment; 121 - Shielding plate; 130 - Cantilever drive mechanism; 131 - Cantilever; 132 - Drive module; 133 - Precision adjustment platform; 134 - Support plate; 1321 - U-shaped adjustment hole; 135 - Anti-tilting mechanism; 136 - Connecting plate; 137 - Second slide rail; 138 - Bracket; a - Neutron slit assembly; b - Sample; c - Diffraction neutron beam. Detailed Implementation

[0033] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this application; the terms “comprising” and “having”, and any variations thereof, in the specification and the foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0035] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more (including two), unless otherwise explicitly defined.

[0036] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0037] In the description of the embodiments of this application, the technical terms "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "inner", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0038] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical terms such as "connection" and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can also refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0039] Example This application provides a multi-level nested neutron detector front-end shielding device. Figure 1 For a structural schematic diagram of the multi-level nested neutron detector front-end shielding device provided in this application, please refer to [link / reference]. Figure 1 The multi-level nested neutron detector front-end shielding device includes: a multi-level telescopic shielding structure 110, a shielding chamber 120, and a cantilever drive mechanism 130.

[0040] Figure 2 This is an exploded view of the multi-level telescopic shielding structure provided in this application. Figure 3 For a cross-sectional view of the multi-level telescopic shielding structure provided in this application, please refer to [link / reference]. Figure 2 and Figure 3The multi-stage telescopic shielding structure 110 has multiple shielding sleeves 111 that are sequentially slidably connected and interconnected along a first horizontal direction A. Along the first horizontal direction A, the preceding shielding sleeve is fitted around the outer periphery of the following shielding sleeve 111. A first annular protrusion 112 is provided on the inner wall of the preceding shielding sleeve 111 near the following shielding sleeve 111, surrounding the first horizontal direction A. A second annular protrusion 113 is provided on the outer wall of the following shielding sleeve 111 near the preceding shielding sleeve 111, surrounding the first horizontal direction A. The projections of the first annular protrusion 112 and the second annular protrusion 113 on the first horizontal direction A overlap, and the first annular protrusion 112 and the second annular protrusion 113 can interlock with each other. The central axes of each shielding sleeve 111 coincide. The entire multi-stage telescopic shielding structure 110 extends and retracts along the first horizontal direction A.

[0041] It is understood that in this application, along the first horizontal direction A, the first shielding sleeve 111 of two adjacent shielding sleeves 111 refers to the shielding sleeve 111 closer to the shielding chamber 120, and the second shielding sleeve 111 is the shielding sleeve 111 farther away from the shielding chamber 120.

[0042] Please see Figure 1 The inner cavity of the shielding chamber 120 is used to house a neutron detector (not shown in the figure). The shielding chamber 120 is fixedly connected to and communicates with the first shielding sleeve 111 along the first horizontal direction A. Specifically, the end face of the shielding chamber 120 near the multi-stage telescopic shielding structure 110 has a main light-transmitting port, which communicates with the interior of the multi-stage telescopic shielding structure 110 to ensure that the diffracted neutron beam c is smoothly transmitted to the neutron detector inside the shielding chamber 120. The central axis of the shielding chamber 120 coincides with the central axis of the multi-stage telescopic shielding structure 110. It can be understood that both the central axis of the shielding chamber 120 and the central axis of the multi-stage telescopic shielding structure 110 are parallel to the first horizontal direction A.

[0043] Figure 4 For a structural schematic diagram of the cantilever drive mechanism provided in this application, please refer to [link / reference]. Figure 1 and Figure 4 The cantilever drive mechanism 130 is located on the top of the shielding chamber 120. The cantilever drive mechanism 130 includes a cantilever 131 and a drive module 132. The drive module 132 is used to drive the multi-stage telescopic shielding structure 110 to extend and retract along the first horizontal direction A. The cantilever 131 extends along the first horizontal direction A. A precision adjustment table 133 is provided at the end of the cantilever 131 away from the shielding chamber 120 and is connected to the end of the multi-stage telescopic shielding structure 110 away from the shielding chamber 120. The precision adjustment table 133 is used to adjust the position of the center of the port of the multi-stage telescopic shielding structure 110 away from the shielding chamber 120.

[0044] The multi-level nested neutron detector front-end shielding device provided in this application can be used in a neutron diffraction stress analysis spectrometer. The port of the multi-level telescopic shielding structure 110 furthest from the shielding chamber 120 is connected to the neutron slit assembly a. The diffracted neutron beam c generated by sample b enters the multi-level telescopic shielding structure 110 through the neutron slit assembly a, and then enters the shielding chamber 120 to reach the neutron detector. It is understood that during neutron detector installation, the center of the neutron detector coincides with the central axis of the multi-level telescopic shielding structure 110 to ensure smooth transmission of the diffracted neutron beam c along the central axis and avoid optical path deviation.

[0045] In the multi-level nested neutron detector front-end shielding device provided in this application, the multi-level telescopic shielding structure 110 is used to realize the transmission of diffracted neutron beam c and the shielding of stray neutrons. By setting shielding sleeves 111 that are sequentially slidably connected, interconnected and nested in sequence, sufficient telescopic stroke can be provided, and the lower end of the multi-level telescopic shielding structure 110 can form a stepped structure with an upward extension tendency. The multi-level telescopic shielding structure 110 is driven to telescopically extend and retract by a cantilever drive mechanism 130 set at the top of the shielding chamber 120. The entire cantilever drive mechanism 130 adopts a "crane" layout, so that the lower part of the entire multi-level nested neutron detector front-end shielding device near the sample b forms a completely suspended space, which can avoid obstacles in the space below and safely avoid large and complex samples b of different sizes and shapes. Sufficient space is provided for the multi-degree-of-freedom rotation of sample b, thereby solving the spatial interference problem and ensuring the spatial resolution and data accuracy of the neutron detector, greatly expanding the application range. By setting the first annular protrusion 112 and the second annular protrusion 113 with specific structures to form a non-straight-slit radiation attenuation channel, the multi-level telescopic shielding structure 110 can always be in a sealed shielding state during the telescopic process, realizing dynamic sealed shielding and effectively avoiding neutron leakage. By setting the precision adjustment stage 133 to precisely adjust the position of the port center of the multi-level telescopic shielding structure 110 away from the shielding chamber 120, the positioning accuracy of the front shielding device of the neutron detector and the optical path can be guaranteed. In addition, setting the cantilever drive mechanism 130 above the shielding chamber 120 can reduce the moment of inertia.

[0046] Therefore, the multi-level nested neutron detector front-end shielding device provided in this application can effectively suppress stray neutron leakage (neutron leakage rate as low as below 0.1%) while achieving large-stroke (up to 300 mm) telescopic avoidance of sample b, effectively reduce the background noise of the neutron detector, improve the quality of the detection signal, improve the signal-to-noise ratio of the neutron detector (more than 3 times higher), and ensure the positioning accuracy of the neutron detector front-end shielding device and the optical path (±0.1 mm), providing reliable shielding protection for the neutron detector. It has advantages such as stable structure, convenient operation, and strong compatibility. The entire device adopts a modular design, which is convenient for processing, manufacturing, transportation and assembly, reducing production and use costs.

[0047] It should be noted that this application does not limit the neutron detector installed in the shielded chamber 120. For example, the neutron detector can be a high-sensitivity position-sensitive detector or a single-tube detector array.

[0048] For ease of description, the second horizontal direction B is referred to in the following text. In this application, the second horizontal direction B refers to the direction that is perpendicular to both the first horizontal direction A and the height direction. Specifically, in the following text, the first horizontal direction A is also referred to as the front-back direction, and the second horizontal direction B is also referred to as the left-right direction.

[0049] Please see Figure 2 and Figure 3 In some optional embodiments of this application, in the multi-stage telescopic shielding structure 110, two adjacent shielding sleeves 111 are slidably connected by a first slide rail 114 extending along the first horizontal direction A. By setting the first slide rail 114, it is beneficial to ensure the smooth and stable telescopic movement of the entire multi-stage telescopic shielding structure 110.

[0050] Furthermore, along the first horizontal direction A, a first slide rail 114 is embedded in the inner wall of the preceding shielding sleeve, and the following shielding sleeve 111 is slidably connected to the first slide rail 114 on the preceding shielding sleeve through a rolling connector, which is engaged within the first slide rail 114. This method, combining rolling friction and embedding, reduces the size of the splicing gaps, provides precise guidance and positioning, and forms a self-supporting structure to distribute weight, reducing the expansion and contraction resistance of the entire multi-stage telescopic shielding structure 110 and ensuring the smooth and stable expansion and contraction of the entire multi-stage telescopic shielding structure 110.

[0051] As an example, the first slide rail 114 is model THK SR25, the gap of the first slide rail 114 is controlled within 0.02mm, and the telescopic resistance of the multi-level telescopic shielding structure 110 is less than 5N.

[0052] In some optional embodiments of this application, the projection of the shielding sleeve 111 on the first horizontal direction A is rectangular; the first annular protrusion 112 and the second annular protrusion 113 are both annular stepped structures arranged around the first horizontal direction A. The first annular protrusion 112 forms an L-shaped structure with the inner wall of the shielding sleeve 111, and the second annular protrusion 113 forms an L-shaped structure with the outer wall of the shielding sleeve 111. The first annular protrusion 112 and the second annular protrusion 113 form a bidirectional interlocking L-shaped nested self-supporting structure. The size and position of the two are precisely matched, so that the two annular stepped structures always maintain radial overlap during the expansion and contraction process, forming a Z-shaped radiation attenuation channel, which structurally blocks the direct path of stray neutrons, thereby facilitating the dynamic sealing and shielding of the multi-level expansion and contraction shielding structure 110 during the expansion and contraction process.

[0053] As an example, the step height of the first annular protrusion 112 and the step width of the second annular protrusion 113 are both 15mm, so as to ensure that the radial overlap of the first annular protrusion 112 and the second annular protrusion 113 is more than 10mm during the extension and retraction process.

[0054] like Figure 3 There are three shielding sleeves 111; for example, the dimensions of the three shielding sleeves 111 are 250mm×450mm×480mm, 270mm×330mm×360mm, and 230mm×230mm×260mm respectively.

[0055] It should be noted that in other feasible embodiments of this application, the number of shielding sleeves 111 can also be selected according to the actual situation.

[0056] Furthermore, such as Figure 2 As shown, each shielding sleeve 111 is composed of four shielding blocks 115 spliced ​​together, located at the top, bottom, left, and right.

[0057] Furthermore, the shielding block 115 is made of a composite shielding material containing boron polyethylene and lead, which can provide shielding for both neutrons and gamma rays.

[0058] As an example, the shielding block 115 is made of boron-containing polyethylene (containing 50% boron) and has a thickness of 50 mm.

[0059] Figure 5 for Figure 1 Please refer to the enlarged view at point M. Figure 1 and Figure 5In some optional embodiments of this application, the shielding chamber 120 is a square hollow cavity structure, formed by splicing multiple shielding plates 121, and the gap between two adjacent shielding plates 121 is a non-through gap. This method helps to avoid neutron leakage in the shielding chamber 120, thereby ensuring the signal-to-noise ratio and measurement accuracy of the neutron detector signal.

[0060] As an example, the shielding chamber 120 is composed of five shielding plates 121 spliced ​​together in the upper, lower, left, right and front directions (where "front" refers to the direction away from the multi-level telescopic shielding structure 110 of the shielding chamber 120).

[0061] Furthermore, the gap between any two adjacent shielding plates 121 is a Z-shaped gap; the above method can effectively avoid neutron leakage in the shielding chamber 120, thereby ensuring the signal-to-noise ratio and measurement accuracy of the neutron detector signal.

[0062] Furthermore, the gaps between any two adjacent shielding plates 121 are sealed with acetone sealant to further enhance the shielding effect.

[0063] In some optional embodiments of this application, a non-through-hole (not shown in the figure) is provided on the shielding plate 121 of the shielding chamber 120 away from the multi-level telescopic shielding structure 110; the aforementioned non-through-hole can serve as a cable channel for the neutron detector, which is beneficial to ensure that the cable passes through while avoiding stray neutron leakage.

[0064] As an example, the non-straight-through holes provided on the shielding plate 121 of the shielding chamber 120, which is away from the multi-level telescopic shielding structure 110, are labyrinth-type through holes, and the size of the labyrinth-type through holes can be 50mm × 100mm.

[0065] In some optional embodiments of this application, the shielding plate 121 of the shielding chamber 120 along the second horizontal direction B is a detachable shielding plate; the above method facilitates the installation, debugging and maintenance of the neutron detector.

[0066] In some optional embodiments of this application, the shielding plate 121 of the shielding chamber 120 along the second horizontal direction B is hinged to the shielding plate 121 of the shielding chamber 120 away from the multi-level telescopic shielding structure 110; the above method can realize quick opening and closing, which is convenient for the installation, debugging and maintenance of the neutron detector.

[0067] In some optional embodiments of this application, the shielding chamber 120 has a support structure for the fixed cantilever drive mechanism 130 and the shielding plate 121 around its perimeter and top to improve the stability of the overall structure.

[0068] As an example, the inner dimensions of the shielding chamber 120 are 600mm×600mm×550mm (length×width×height), the shielding plate 121 is a boron-containing polyethylene shielding plate (containing 50% boron), the thickness of the shielding plate 121 is 50mm, and the size of the main light transmission port is 470mm×430mm.

[0069] Please see Figure 1 and Figure 4 In some optional embodiments of this application, a support plate 134 is fixedly connected to the top of the shielding chamber 120, and a linear drive module 132 is fixed to the support plate 134. A U-shaped adjustment hole 1321 is provided at the bottom of the linear drive module 132. The linear drive module 132 is connected to the support plate 134 via a fixing member extending into the U-shaped adjustment hole 1321, and the fixing member is configured to selectively move along a second horizontal direction B within the U-shaped adjustment hole 1321. This arrangement facilitates the initial alignment adjustment of the drive module 132, ensuring that the movement trajectory of the drive module 132 is parallel to the central axis of the multi-stage telescopic shielding structure 110.

[0070] As an example, the fastener is a bolt, the support plate 134 is made of a high-strength aluminum alloy plate with a thickness of 20mm, and the bolt holes for mounting the drive module 132 are integrated; the U-shaped adjustment hole 1321 is 15mm long and 8.6mm wide; the linear drive module 132 adopts a precision ball screw module (model: PMI-KM3005) with a stroke of 400mm and a positioning accuracy of ±0.05mm.

[0071] In this application, one end of the cantilever 131 is fixed above the shielding chamber 120, and the other end of the cantilever 131 extends above the multi-stage telescopic shielding structure 110 and is connected to the precision adjustment platform 133; in order to prevent the cantilever 131 from tilting and improve structural stability, an anti-tilting mechanism 135 is installed at the end of the support plate 134 away from the precision step platform.

[0072] As an example, the anti-tilting mechanism 135 is a U-shaped bracket.

[0073] In some optional embodiments of this application, the cantilever 131 and the precision adjustment stage 133 are connected by a connecting plate 136. The precision adjustment stage 133 is configured to move relative to the connecting plate 136 along the height direction and the second horizontal direction B. The precision adjustment stage 133 has a first limiting member and a second limiting member. The first limiting member is configured to selectively restrict the movement of the precision adjustment stage 133 along the height direction, and the second limiting member is configured to selectively restrict the movement of the precision adjustment stage along the second horizontal direction B. This configuration enables two-dimensional displacement adjustment of the precision adjustment stage 133. The first and second limiting members provide a locking function for the precision adjustment stage 133, thereby compensating for the deflection deformation of the cantilever 131 caused by gravity and changes in its extension length, and thus ensuring the positioning accuracy of the neutron detector front-end shielding device and the optical path (up to ±0.1 mm).

[0074] As an example, the connecting plate 136 is made of metal; the cantilever 131 is made of high-precision bearing steel or high-strength aluminum alloy, for example, the cantilever 131 is made of 6061 aluminum alloy; the cross-sectional dimensions of the cantilever 131 are 40mm × 120mm, and the length of the cantilever 131 is 1250mm; the precision adjustment stage 133 adopts a manual two-dimensional displacement stage (model: Newport460A), with a stroke of ±12.5mm, a positioning accuracy of ±0.01mm, and a locking knob.

[0075] In some optional embodiments of this application, the movable end of the precision adjustment stage 133 is fixedly connected to the end of the multi-level telescopic shielding structure 110 away from the shielding chamber 120, so as to adjust the position of the center of the port of the multi-level telescopic shielding structure 110 away from the shielding chamber 120.

[0076] In some optional embodiments of this application, the cantilever drive mechanism 130 further includes a second slide rail 137 extending along a first horizontal direction A; one end of the second slide rail 137 is connected to the support plate 134 at the top of the shielding chamber 120, and the other end extends above the multi-stage telescopic shielding structure 110, satisfying the maximum stroke of the telescopic shielding structure 110; the shielding sleeve 111 is slidably connected to the second slide rail 137 through a bracket 138, and the drive module 132 is used to drive the bracket 138 to move along the extension direction of the second slide rail 137; the bracket 138 can bear the weight of the shielding sleeve 111 to distribute the load, which is beneficial to improving the structural rigidity and telescopic movement stability.

[0077] As an example, bracket 138 is an L-shaped metal bracket.

[0078] Furthermore, in some optional embodiments of this application, the cantilever drive mechanism 130 has two second slide rails 137, which are respectively installed on both sides of the drive module 132. The shielding sleeve 111 is slidably connected to both second slide rails 137 through the bracket 138. By having the two second slide rails 137 share the mass of the multi-stage telescopic shielding structure 110's extension and retraction, it is beneficial to ensure the overall structural stability.

[0079] As an example, the second slide rail 137 is made of high-precision bearing steel; the second slide rail 137 is a linear slide rail, model THK SR3; the distance between the second slide rail 137 and the cantilever 131 is 50mm, and the length of the second slide rail 137 is 430mm.

[0080] Specifically, the assembly and usage process of the multi-level nested neutron detector front-end shielding device provided in this application is as follows: S1, Device Assembly: Assemble and fix the shielding plates 121 of the shielding chamber 120, and install the top support plate 134; install the drive module 132 on the support plate 134, and adjust the position of the drive module 132 through the U-shaped horizontal adjustment holes to ensure that the movement direction of the drive module 132 is consistent with the central axis of the multi-stage telescopic shielding structure 110; fix the cantilever 131 to the moving end of the drive module 132, install an anti-tilting mechanism 135 at the end of the cantilever 131 closest to the shielding chamber 120, and install an anti-tilting mechanism 135 at the end of the cantilever 131 furthest from the shielding chamber 120. A precision adjustment platform 133 is installed at one end, and two second slide rails 137 are installed on the support plate 134. The shielding sleeve 111 of the multi-level telescopic shielding structure 110, which is close to the shielding chamber 120, is coaxially connected to the main light-transmitting port of the shielding chamber 120. At the same time, the multi-level telescopic shielding structure 110 is connected to the second slide rails 137 through the bracket 138. The neutron detector is installed inside the shielding chamber 120, and the signal cable is connected and passes through the labyrinth-type through hole on the shielding plate 121 of the shielding chamber 120, which is away from the multi-level telescopic shielding structure 110.

[0081] S2, Precision calibration: Adjust the displacement of the height direction of the precision adjustment stage 133 relative to the second horizontal direction B. Detect the position of the port center of the multi-level telescopic shielding structure 110 furthest from the shielding chamber 120 using a laser collimator. Control the drive module 132 to move back and forth using a control program to ensure that the movement trajectory of the drive module 132 is parallel to the central axis of the multi-level telescopic shielding structure 110. After calibration, fix the first and second limiters to lock the precision adjustment stage 133.

[0082] S3, Sample b measurement: Place sample b at the measurement station, start the drive module 132, and drive the multi-stage telescopic shielding structure 110 to extend to the preset position; the incident neutron beam irradiates the sample b, and the generated diffracted neutron beam c is transmitted through the neutron slit assembly a and the multi-stage telescopic shielding structure 110 to the neutron detector in the shielding chamber 120. The neutron detector collects the diffraction signal; according to the measurement requirements, control the rotation of sample b to adjust its attitude. If there is a risk of spatial interference, drive the multi-stage telescopic shielding structure 110 to retract and avoid it through the drive module 132. After adjustment, extend it to the measurement position to continue the measurement.

[0083] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A multi-level nested neutron detector front-end shielding device, characterized in that, include: A multi-level telescopic shielding structure has multiple shielding sleeves that are sequentially slidably connected and interconnected along a first horizontal direction. Along the first horizontal direction, the preceding shielding sleeve is fitted around the outer periphery of the following shielding sleeve. A first annular protrusion surrounding the first horizontal direction is provided on the inner wall of the preceding shielding sleeve near the following shielding sleeve. A second annular protrusion surrounding the first horizontal direction is provided on the outer wall of the following shielding sleeve near the preceding shielding sleeve. The projections of the first and second annular protrusions in the first horizontal direction overlap, and the first and second annular protrusions can interlock with each other. The central axes of each shielding sleeve coincide. A shielding chamber, the inner cavity of which is used to house a neutron detector, the shielding chamber being fixedly connected to and communicating with the first shielding sleeve along the first horizontal direction; A cantilever drive mechanism is disposed on the top of the shielding chamber. The cantilever drive mechanism includes a cantilever and a drive module. The drive module is used to drive the multi-stage telescopic shielding structure to extend and retract. The cantilever extends along the first horizontal direction. A precision adjustment platform is provided at the end of the cantilever away from the shielding chamber and is connected to the end of the multi-stage telescopic shielding structure away from the shielding chamber. The precision adjustment platform is used to adjust the position of the center of the port of the multi-stage telescopic shielding structure away from the shielding chamber.

2. The multi-level nested neutron detector front-end shielding device according to claim 1, characterized in that, In the multi-level telescopic shielding structure, two adjacent shielding sleeves are slidably connected by a first slide rail extending along the first horizontal direction.

3. The multi-level nested neutron detector front-end shielding device according to claim 2, characterized in that, Along the first horizontal direction, the first slide rail is embedded in the inner wall of the first shielding sleeve, and the second shielding sleeve is slidably connected to the first slide rail on the first shielding sleeve through a rolling connector, which is engaged in the first slide rail.

4. The multi-level nested neutron detector front-end shielding device according to any one of claims 1 to 3, characterized in that, The shielding chamber is a square hollow cavity structure, which is formed by splicing multiple shielding plates, and the gap between any two adjacent shielding plates is a non-through gap.

5. The multi-level nested neutron detector front-end shielding device according to claim 4, characterized in that, The gap between any two adjacent shielding plates is a Z-shaped gap.

6. The multi-level nested neutron detector front-end shielding device according to claim 4, characterized in that, The shielding plate of the shielding chamber, which is far from the multi-level telescopic shielding structure, is provided with non-straight-through holes.

7. The multi-level nested neutron detector front-end shielding device according to claim 4, characterized in that, The shielding plate of the shielding chamber along the second horizontal direction is a detachable shielding plate; or / and, the shielding plate of the shielding chamber along the second horizontal direction is hinged to the shielding plate of the shielding chamber away from the multi-level telescopic shielding structure; The second horizontal direction is perpendicular to the first horizontal direction.

8. The multi-level nested neutron detector front-end shielding device according to any one of claims 1 to 3, characterized in that, A support plate is fixedly connected to the top of the shielding chamber, the drive module is fixed to the support plate, and a U-shaped adjustment hole is provided at the bottom of the drive module. The drive module is connected to the support plate through a fixing member that extends into the U-shaped adjustment hole, and the fixing member is configured to selectively move in the second horizontal direction within the U-shaped adjustment hole. The second horizontal direction is perpendicular to the first horizontal direction.

9. The multi-level nested neutron detector front-end shielding device according to any one of claims 1 to 3, characterized in that, The cantilever is connected to the precision adjustment platform via a connecting plate, and the precision adjustment platform is configured to move relative to the connecting plate along a height direction and a second horizontal direction; wherein the second horizontal direction is perpendicular to the first horizontal direction; The precision adjustment stage has a first limiting member and a second limiting member, the first limiting member being configured to selectively restrict the movement of the precision adjustment stage along the height direction, and the second limiting member being configured to selectively restrict the movement of the precision adjustment stage along the second horizontal direction.

10. The multi-level nested neutron detector front-end shielding device according to any one of claims 1 to 3, characterized in that, The cantilever drive mechanism further includes a second slide rail extending along the first horizontal direction. The shielding sleeve is slidably connected to the second slide rail via a bracket. The drive module is used to drive the bracket to move along the extension direction of the second slide rail.

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