Delayed neutron probe calibration device and method

Abstract

This application relates to the field of ionizing radiation metrology technology, and discloses a delayed neutron detector calibration device and method. The delayed neutron detector calibration device includes a housing, a point neutron source, and a moving component. The housing defines an independent working cavity and a mounting cavity. The point neutron source is disposed within the mounting cavity. The moving component is disposed within the housing, with its connecting end extending into the working cavity and connected to the detector. The moving component is used to move the detector relative to the point neutron source, aligning different positions of the detector with the point neutron source, and acquiring detector readings for segmented calibration. This application enables on-site calibration of delayed neutron detectors, reducing the calibration time and complexity of the process.

Description

Technical Field

[0001] This application belongs to the field of ionizing radiation metrology technology, specifically relating to a slow-emission neutron detector calibration device and method. Background Technology

[0002] In nuclear reactor safety systems, delayed neutron emission tomography (DEPT) in the primary circuit water is used to detect fuel element damage. DEPT monitoring stations are primarily designed far from the reactor core to minimize interference. Primary circuit water is piped into a specially designed detection device to detect delayed neutron emission tomography. Within the detection device, the primary circuit water flows in a spiral tube, increasing the flow time (detection time) and making the neutron field more uniform. The detection device has an external moderation layer and a shielding layer to eliminate interference from external neutrons or gamma rays, and an internal moderation layer to improve detection efficiency. At the center is the neutron detection instrument, typically consisting of a boron trifluoride (BF3) detector and a helium-3 neutron detector (…). 3 He) detector.

[0003] By detecting the intensity of delayed neutrons, the extent of fuel element damage can be assessed. When the fuel cladding breach is small, the reactor can continue operating with the damage, avoiding shutdown and economic losses. However, when the breach is large, the fuel assembly must be replaced. Failure to shut down the reactor when the breach is large will result in excessive activity concentration in the primary coolant circuit, compromising reactor safety.

[0004] Reactor control operators can take timely measures based on data from the delayed neutron monitoring station to ensure the safety of the nuclear reactor, personnel, and the environment, while also considering the reactor's economic viability. Therefore, the accuracy of the delayed neutron detector measurements has a significant impact on the reactor's safety and economic performance.

[0005] During the reactor's service life, the neutron detectors used in the delayed neutron monitoring station need to be replaced periodically. Due to the lack of corresponding calibration standards and the inconvenience of transporting delayed neutron detectors and their inability to be removed from their posts for extended periods, it is difficult to transport delayed neutron detectors to the standard metrology verification center for calibration, resulting in a lengthy and challenging calibration process. Summary of the Invention

[0006] This application aims to address at least one of the technical problems existing in the related art.

[0007] Therefore, the first aspect of this application provides a delayed neutron detector calibration apparatus.

[0008] The second aspect of this application provides a method for calibrating a delayed neutron detector.

[0009] In view of this, according to a first aspect of the embodiments of this application, a delayed neutron detector calibration device is proposed, comprising: a housing defining an independent working cavity and a mounting cavity; a point neutron source disposed within the mounting cavity; and a moving component disposed within the housing, wherein a connecting end of the moving component extends into the working cavity and is connected to the detector; wherein the moving component is used to drive the detector to move relative to the point neutron source, so that different positions of the detector correspond to the point neutron source, and to acquire readings of the detector for segmented calibration of the detector.

[0010] In one possible implementation, the calibration device further includes: a shaper disposed outside the point neutron source on the side facing the detector, for adjusting the uniformity of the thermal neutron field formed by the point neutron source; the shaper has an axisymmetric structure, the axis of the shaper passes through the point neutron source, and along the direction from the point neutron source to the detector, the distance between the sidewall of the shaper and the axis of the shaper gradually decreases.

[0011] In one possible implementation, the working cavity of the housing surrounds at least a portion of the mounting cavity, and the working cavity is filled with a filling medium for slowing down and shielding the fast neutrons generated by the point neutron source, the filling medium including water.

[0012] In one possible implementation, the moving component includes: a first slide platform disposed on the housing; and a lifting platform slidably disposed on the first slide platform, the lifting platform including the connecting end; wherein the first slide platform is used to drive the lifting platform to move to drive the detector to move along a first direction, and the lifting platform is used to drive the detector to move along a second direction, the second direction being perpendicular to the first direction.

[0013] In one possible implementation, the moving component further includes: a second slide table disposed at the connecting end, the detector disposed on the second slide table, the second slide table being used to drive the detector to move along the first direction; wherein, when the sensitive area of ​​the detector is divided into multiple detection segments, the first slide table and / or the second slide table are used to drive the detector to move so that different detection segments correspond to the point neutron source.

[0014] In one possible implementation, the thermal neutron fluence rate of the thermal neutron field formed by the point neutron source is 1 cm⁻¹. -2 ·s -1 Up to 100cm -2 ·s -1 .

[0015] According to a second aspect of the embodiments of this application, a method for calibrating a delayed neutron detector is proposed. The method employs a delayed neutron detector calibration device as described above to determine the calibration factor of the calibration detector. The sensitive area of ​​a standard detector is divided into multiple standard detection segments, and the sensitive area of ​​the calibration detector is divided into multiple calibration detection segments. Each calibration detection segment corresponds one-to-one with one of the multiple standard detection segments. The calibration method includes the following steps: obtaining preset coordinates of a preset calibration position relative to a point neutron source, and the thermal neutron fluence rate at the preset coordinates; controlling a moving component to move the standard detector to the preset coordinates based on the preset coordinates, and obtaining multiple first readings corresponding one-to-one with each of the multiple standard detection segments; controlling the moving component to move the calibration detector to the preset coordinates based on the preset coordinates, and obtaining multiple second readings corresponding one-to-one with each of the multiple calibration detection segments, where each second reading corresponds one-to-one with one of the multiple first readings; and determining the calibration factor of the calibration detector at the thermal neutron fluence rate based on the multiple first readings and the multiple second readings.

[0016] In one possible implementation, the step of controlling the movement component to move the standard detector to the preset coordinates and obtaining multiple first readings corresponding to the multiple standard detection segments includes: controlling the movement component to move the standard detection segment closest to the standard detector to the preset coordinates and obtaining a first reading corresponding to the standard detection segment; obtaining a first translational distance of the standard detector; and controlling the movement component to move the standard detector sequentially along a first direction by the first translational distance, so that the remaining standard detection segments are sequentially moved to the preset coordinates and obtaining a first reading corresponding to the remaining standard detection segments, thereby obtaining multiple first readings corresponding to the multiple standard detection segments.

[0017] In one possible implementation, the step of controlling the movement component to move the calibration detector to the preset coordinates and obtaining multiple second readings corresponding to the multiple calibration detector segments includes: controlling the movement component to move the calibration detector segment closest to the calibration detector to the preset coordinates and obtaining a second reading corresponding to the calibration detector segment; obtaining a second translation distance of the calibration detector; and controlling the movement component to move the standard detector sequentially along a first direction by the second translation distance, thereby moving the remaining calibration detector segments sequentially to the preset coordinates and obtaining a second reading corresponding to the remaining calibration detector segments, thus obtaining multiple second readings corresponding to the multiple calibration detector segments.

[0018] In one possible implementation, the step of determining the calibration factor of the calibration detector at the thermal neutron flux rate based on a plurality of first readings and a plurality of second readings includes: calculating the proportional relationship between the second reading and the corresponding first reading based on the plurality of first readings and a plurality of second readings to obtain a plurality of segmented calibration factors; and calculating the average value of the plurality of segmented calibration factors to obtain the calibration factor of the calibration detector at the thermal neutron flux rate.

[0019] The delayed neutron detector calibration device and method provided in this application can achieve at least the following technical effects: In this application, the enclosure defines independent working and mounting chambers, providing space for the calibration of the delayed neutron detector and facilitating transportation and relocation, thus enabling on-site calibration of the delayed neutron detector. A point neutron source is located within the mounting chamber, isolating it from the working chamber to protect it when a filling medium is placed within the working chamber. Fast neutrons are generated by the point neutron source to provide a thermal neutron field, and the point neutron source is easily transported to the field, ensuring safety and feasibility for on-site calibration of the delayed neutron detector. The connecting end of the moving component extends into the working chamber and connects to the detector, enabling the moving component to move the detector relative to the point neutron source. That is, the point neutron source remains stationary, and the moving component moves different positions of the detector into the thermal neutron field. Different positions of the detector correspond to the point neutron source; that is, the detector's sensitivity is divided into multiple detection segments. By moving the detector, different detection segments are moved to the thermal neutron field formed by the point neutron source, and the thermal neutron field scans the detection segments. The calibration device acquires detector readings, specifically, readings of the detector at different detection sections within a thermal neutron field, for segmented calibration of the detector. This calibration device enables on-site calibration of delayed neutron detectors, reducing the time and difficulty of the calibration process, alleviating the inconvenience of transporting delayed neutron detectors to standard metrology verification and calibration facilities, and providing metrological assurance for reactor safety.

[0020] The above general description and the description below are exemplary and illustrative only and are not intended to limit this application. Attached Figure Description

[0021] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations and drawings do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are shown as similar elements. The drawings are not to be scaled. And wherein: Figure 1 This is a three-dimensional structural diagram of the calibration device provided in the embodiments of this disclosure; Figure 2 for Figure 1 A schematic diagram of the front view structure of the calibration device provided in the embodiment shown; Figure 3 for Figure 1 A side view of the calibration device provided in the embodiment shown; Figure 4 for Figure 1 A top view of the calibration device provided in the embodiment shown; Figure 5 This is a partial structural schematic diagram of the mobile component provided in an embodiment of the present disclosure; Figure 6 This is a schematic diagram of the installation structure of a neutron generator provided in an embodiment of this disclosure; Figure 7 A schematic diagram showing the arrangement of the point neutron source, shaper, and detector provided in an embodiment of this disclosure; Figure 8 A schematic diagram illustrating the principle of segmented calibration of the calibration detector provided in this embodiment of the disclosure; Figure 9 A flowchart of the calibration method provided in the embodiments of this disclosure; Figure 10 A schematic diagram of the structure of the control device provided in the embodiments of this disclosure.

[0022] The reference numerals in the attached figures are as follows: 100: Calibration device; 101: Housing; 102: Working chamber; 103: Mounting chamber; 104: Point neutron source; 105: Neutron generator; 106: Moving component; 107: First slide; 108: Lifting platform; 109: Second slide; 110: Shaper; 111: Third slide; 112: Isolation box; 200: Calibration detector; 201: Sensitive area; 202: First calibration detection section; 203: Second calibration detection section; 204: Third calibration detection section; 205: Fourth calibration detection section; 800: Control device; 802: Processor; 804: Memory; 806: Communication interface; 808: Bus. Detailed Implementation

[0023] To provide a more detailed understanding of the features and technical content of the embodiments of this disclosure, the implementation of the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for illustrative purposes only and are not intended to limit the embodiments of this disclosure. In the following technical description, for ease of explanation, several details are used to provide a full understanding of the disclosed embodiments. However, one or more embodiments may still be implemented without these details. In other cases, well-known structures and devices may be simplified in their depiction to simplify the drawings.

[0024] The terms "first," "second," etc., in the description, claims, and accompanying drawings of this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this disclosure described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0025] In this disclosure, the terms "upper," "lower," "inner," "middle," "outer," "front," and "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for better description of the embodiments of this disclosure and their implementations, and are not intended to limit the indicated devices, elements, or components to having a specific orientation, or to require them to be constructed and operated in a specific orientation. Furthermore, some of the aforementioned terms may be used to indicate other meanings besides orientation or positional relationship; for example, the term "upper" may in some cases indicate a dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in the embodiments of this disclosure according to the specific circumstances.

[0026] Furthermore, the terms "set up," "connect," and "fix" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this disclosure according to the specific circumstances.

[0027] Unless otherwise stated, the term "multiple" means two or more.

[0028] The term "and / or" describes an association between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or A and B.

[0029] It should be noted that, unless otherwise specified, the embodiments and features described in the present disclosure can be combined with each other.

[0030] Combination Figures 1 to 7As shown, according to a first aspect of the embodiments of this application, a delayed neutron detector calibration device 100 is proposed for on-site calibration of a delayed neutron detector. The calibration device 100 includes a housing 101, a point neutron source 104, and a moving assembly 106. The housing 101 defines independent working chambers 102 and mounting chambers 103. The point neutron source 104 is disposed within the mounting chamber 103. The moving assembly 106 is disposed within the housing 101, with its connecting end extending into the working chamber 102 and connected to the detector. The moving assembly 106 is used to move the detector relative to the point neutron source 104, aligning different positions of the detector with the point neutron source 104, and acquiring detector readings for segmented calibration of the detector.

[0031] In this embodiment, the housing 101 defines independent working chamber 102 and mounting chamber 103, providing space for the calibration of the delayed neutron detector and facilitating transportation and relocation, thus aiding in on-site calibration of the delayed neutron detector. When the filling medium in the working chamber 102 is liquid, the independent operation of the working chamber 102 and mounting chamber 103 effectively isolates the point neutron source 104 from the liquid.

[0032] In this embodiment, fast neutrons are generated by a point neutron source 104 to provide a thermal neutron field. Furthermore, the point neutron source 104 is easily transported to the field, providing a safe and feasible method for on-site calibration of the delayed neutron detector. In this embodiment, the working cavity 102 surrounds at least a portion of the mounting cavity 103, and the point neutron source 104 is disposed within the mounting cavity 103, which helps the point neutron source 104 form a thermal neutron field. In practical applications, a filling medium can be placed within the working cavity 102 to surround at least a portion of the mounting cavity 103 for shielding, thereby improving the safety of on-site calibration of the delayed neutron detector.

[0033] In this embodiment, the connecting end of the moving component 106 extends into the working cavity 102, and the connecting end of the moving component 106 is connected to the detector, so that the moving component 106 drives the detector to move relative to the point neutron source 104. That is, the point neutron source 104 remains stationary, and the moving component 106 moves different positions of the detector into the thermal neutron field (i.e., makes the detector move along...). Figure 1(Moving left and right in the middle). Different positions of the detector correspond to the point neutron source 104, that is, the detector's sensitivity is divided into multiple detection segments. By moving the detector, different detection segments are moved to the thermal neutron field formed by the point neutron source 104, and the detection segments are scanned by the thermal neutron field. The detector readings are obtained, that is, the detector readings when different detection segments are located in the thermal neutron field are obtained, which are used for segment calibration of the detector. Specifically, by obtaining the detector readings when different detection segments are located in the thermal neutron field, different segment calibration factors for different detection segments are obtained, and then the detector calibration factor is obtained to achieve segment calibration of the detector.

[0034] In other words, this embodiment performs on-site segmented calibration of a relatively long detector based on the coverage area of ​​the thermal neutron field formed by the point neutron source 104. That is, different positions of the detector are moved into the thermal neutron field by the moving component 106 to achieve on-site segmented calibration of the detector. Of course, if the thermal neutron field formed by the point neutron source 104 can cover the sensitive area 201 of the detector, calibration can also be performed directly on-site without using the segmented calibration method.

[0035] It should be noted that the detector in this embodiment is for simplification, to facilitate the explanation of the calibration process of the delayed neutron detector by the calibration device 100. The following description of the standard detector and calibration detector 200 being installed in the calibration device 100 refers to the detector description.

[0036] In this embodiment, the moving component 106 drives the detector to move relative to the point neutron source 104, and can also adjust the height of the detector relative to the point neutron source 104 (i.e., make the detector move along...). Figure 1 (Moving up and down in the middle), the thermal neutron fluence rate is different at different heights, so as to calibrate the detector at different thermal neutron fluence rates.

[0037] The calibration device 100 in this embodiment can perform on-site calibration of the delayed neutron detector, reducing the time and difficulty of the calibration process, alleviating the inconvenience of transporting the delayed neutron detector to standard metrology verification and calibration sites, and providing metrological assurance for reactor safety.

[0038] Combination Figure 1 , Figure 3 and Figure 7 In one possible implementation, the delayed neutron detector calibration device 100 further includes a neutron generator 105. The neutron generator 105 includes a point neutron source 104. The neutron generator 105 is disposed within the mounting cavity 103.

[0039] In this embodiment, the neutron generator 105 includes a point neutron source 104, which can be understood as the neutron generator 105 having only one neutron source, making it convenient to move the neutron generator 105 to the site.

[0040] For example, neutron generator 105 is a DD neutron generator. The DD neutron generator includes a point neutron source 104 for generating fast neutrons, capable of producing 2.5 MeV neutrons. Approximately a point source, the position of the center point of the point neutron source 104 can be adjusted by axially moving the DD neutron generator. The DD neutron generator can be electrically connected to a matching DD neutron generator control device, allowing the control device to adjust the DD neutron generator. For example, during operation, the voltage of the DD neutron generator can be adjusted to obtain a stable neutron yield. Alternatively, after operation is completed or when the calibration device 100 is not in use, the power supply to the DD neutron generator can be turned off to stop neutron production and improve safety.

[0041] Combination Figures 1 to 4 as well as Figure 6 As shown, in one possible implementation, the calibration device 100 further includes a third slide 111. The third slide 111 is disposed in the housing 101 and located within the mounting cavity 103. The neutron generator 105 is disposed on the third slide 111, which is used to move the neutron generator 105 relative to the housing 101 to adjust the position of the point neutron source 104 and facilitate shielding of the neutron generator 105. In this embodiment, the specific structure of the third slide 111 is not limited, as long as it can move the neutron generator 105. For example, an electric push rod, a ball screw structure, etc., can also be used.

[0042] For example, in combination Figure 1 As shown, the mounting cavity 103 is located at the bottom of the housing 101, and the point neutron source 104 is located inside the mounting cavity 103. The calibration device 100 is generally grounded during use to shield neutrons from below the mounting cavity 103 via the ground. The working cavity 102 surrounds the top, front, and rear of the mounting cavity 103, and the filling medium within the working cavity 102 shields neutrons from the top, front, and rear of the mounting cavity 103. The neutron generator 105 is moved relative to the housing 101 by a third slide 111, facilitating the placement of shielding materials (e.g., polyethylene) on the left and right sides of the point neutron source 104 to shield neutrons from both sides. This configuration enhances the safety of the calibration device 100 when calibrating the delayed neutron detector in the field, protecting personnel.

[0043] Combination Figure 2 and Figure 3 As shown, in one possible implementation, the bottom of the housing 101 is provided with casters for easy movement.

[0044] Combination Figure 2 and Figure 3 As shown, in one possible implementation, the bottom of the housing 101 is provided with liftable support feet, which are used to support and fix the housing 101 when it needs to be fixed.

[0045] In one possible implementation, the calibration device 100 also includes a neutron flux monitor for monitoring the neutron flux.

[0046] In actual use, the calibration device 100 can be shut down when the neutron flux meets the preset conditions (which may be conditions that are prone to danger) to ensure safe use.

[0047] Combination Figure 1 , Figure 4 and Figure 5 As shown, in one possible implementation, the calibration device 100 further includes an isolation box 112. The isolation box 112 is detachably connected to the connection end of the moving component 106. The detector is disposed within the isolation box 112.

[0048] In this embodiment, the isolation box 112 is detachably connected to the connection end of the moving component 106, which facilitates the placement of the detector at the connection end of the moving component 106. By placing the detector inside the isolation box 112, when the filling medium in the working chamber 102 is liquid, the detector is isolated from the liquid, thus protecting the detector.

[0049] In practical applications, the calibration device 100 may also include various distance verification devices to verify the corresponding data and achieve high-quality calibration. For example, the distance between the point neutron source 104 and the detector can be measured using a laser rangefinder.

[0050] Combination Figure 7 As shown, in some embodiments, the calibration device 100 further includes a shaper 110. The shaper 110 is disposed on the exterior of the point neutron source 104 facing the detector, and is used to adjust the uniformity of the thermal neutron field formed by the point neutron source 104. The shaper 110 has an axisymmetric structure, and its axis passes through the point neutron source 104. Along the direction from the point neutron source 104 to the detector, the distance between the sidewall of the shaper 110 and its axis gradually decreases.

[0051] In this embodiment, a shaper 110 is disposed on the outside of the point neutron source 104 facing the detector to adjust the uniformity of the thermal neutron field formed by the point neutron source 104. For example, combined with... Figure 7As shown, the shaper 110 is positioned directly above the point neutron source 104, with the point neutron source 104 and the calibration detector 200 located on opposite sides of the shaper 110. The method of mounting the shaper 110 within the housing 101 is not limited; for example, the shaper 110 can be mounted within the housing 101 via a lifting structure.

[0052] In this embodiment, the shaper 110 has an axisymmetric structure, and the axis of the shaper 110 (the position of the axis of the shaper 110 can be referenced) Figure 7 The position of the Y-axis in the diagram) passes through the point neutron source 104, along the direction from the point neutron source 104 to the detector (i.e., Figure 7 (The direction indicated by the Y-axis arrow in the diagram) The distance between the sidewall of the shaper 110 and the axis of the shaper 110 gradually decreases in order to adjust the thermal neutron field to a uniform neutron field within the target range (e.g., a range of 20 cm), thereby achieving uniform thermal neutron flux rate along the detector axis.

[0053] In this embodiment, the distances between the shaper 110 and the point neutron source 104 and the detector are not limited and can be set as needed. For example, the thermal neutron fluence rate can be made less than 20% uniform within a 20 cm range along the detector axis by adjusting the relative positions of the point neutron source 104, the shaper 110, and the calibration detector 200. Alternatively, the thermal neutron fluence rate at the location of the calibration detector 200 can be adjusted by changing the distance between the calibration detector 200 and the point neutron source 104.

[0054] Combination Figure 7 As shown, in one possible implementation, the shape of the shaper 110 includes a conical or frustum-shaped form.

[0055] For example, in combination Figure 7 As shown, the shaper 110 is conical. The cone is an axisymmetric structure, with its axis passing through the point neutron source 104. The base of the cone faces the point neutron source 104, and the apex faces the detector. That is, along the direction from the point neutron source 104 to the detector, the distance between the sidewall of the shaper 110 and its axis gradually decreases to adjust the uniformity of the thermal neutron field formed by the point neutron source 104.

[0056] In one possible implementation, the shaper 110 is made of a neutron-absorbing material, such as boron-containing polyethylene, to achieve the uniformity of the thermal neutron field.

[0057] In some embodiments, the working cavity 102 of the housing 101 surrounds at least a portion of the mounting cavity 103. The working cavity 102 of the housing 101 is filled with a filling medium for slowing down and shielding the fast neutrons generated by the point neutron source 104. The filling medium includes water.

[0058] In this embodiment, a filling medium is provided within the working cavity 102 of the housing 101 to slow down and shield the fast neutrons generated by the point neutron source 104. Specifically, the filling medium located between the point neutron source 104 and the detector is used to slow down the fast neutrons generated by the point neutron source 104 into thermal neutrons for calibration. The filling medium located at other positions in the working cavity 102 is used to shield neutrons during the operation of the calibration device 100, reducing neutron radiation and improving safety.

[0059] In this embodiment, water is used as the filling medium, which can both slow down and shield the fast neutrons generated by the point neutron source 104, and also reduce the transportation burden of the calibration device 100. For example, when the calibration device 100 is being transported or moved (in a non-operating state), the housing 101 is not filled with water, reducing weight and eliminating the need to transport the filling medium separately, thus lowering costs. Of course, the calibration device 100 can also use other filling media to slow down and shield the fast neutrons generated by the point neutron source 104, and there are no restrictions on this.

[0060] In one possible implementation, the housing 101 is equipped with a water level monitoring device for monitoring the water level. For example, it can be used to monitor the water level when water is injected into the housing 101. When the calibration device 100 is working, it uses water to slow down and shield the fast neutrons generated by the point neutron source 104.

[0061] For example, in combination Figure 1 As shown, the mounting cavity 103 is located in the middle of the bottom of the housing 101, and the working cavity 102 surrounds the upper, front, and rear sides of the mounting cavity 103. The outer layer of the mounting cavity 103 is filled with water to a thickness of 20 cm to 40 cm (e.g., 30 cm) to achieve shielding.

[0062] Combination Figures 1 to 5 As shown, in some embodiments, the moving component 106 includes a first slide 107 and a lifting platform 108. The first slide 107 is disposed on the housing 101. The lifting platform 108 is slidably disposed on the first slide 107. The lifting platform 108 includes a connecting end. The first slide 107 is used to move the lifting platform 108 to move the detector along a first direction. The lifting platform 108 is used to move the detector along a second direction. The second direction is perpendicular to the first direction.

[0063] In this embodiment, a first slide 107 is disposed on the housing 101 to drive the detector to move relative to the housing 101 along a first direction. A lifting platform 108 includes a connecting end, on which the detector is disposed, enabling the lifting platform 108 to drive the detector to move relative to the housing 101 along a second direction. Since the second direction is perpendicular to the first direction, the detector can be moved laterally and longitudinally via the first slide 107 and the lifting platform 108.

[0064] For example, in combination Figures 1 to 4 As shown, the first direction is left-right, and the second direction is up-down. The detector is moved up-down by the moving component 106. The thermal neutron fluence rate varies at different positions in the up-down direction, allowing for calibration of the detector at different thermal neutron fluence rates. The detector is also moved left-right by the moving component 106. The thermal neutron fluence rate is approximately the same at different positions in the left-right direction, enabling segmented calibration of the detector. Therefore, in this example, by moving the detector up, down, left, and right by the moving component 106, calibration of the detector at multiple points and different thermal neutron fluence rates can be achieved.

[0065] In this embodiment, the specific structure of the first sliding stage 107 and the lifting stage 108 is not limited, as long as they can move the detector. For example, an electric push rod can be used.

[0066] Combination Figure 5 As shown, in some embodiments, the moving component 106 further includes a second slide 109. The second slide 109 is disposed at the connection end of the moving component 106. The detector is disposed on the second slide 109, which is used to drive the detector to move along a first direction. Wherein, when the sensitive area 201 of the detector is divided into multiple detection segments, the first slide 107 and / or the second slide 109 are used to drive the detector to move so that different detection segments correspond to the point neutron source 104.

[0067] In this embodiment, the detector is moved relative to the housing 101 along a first direction by the second slide 109 to adjust the axial position of the detector, so that different detection segments of the detector are moved to positions corresponding to the point neutron source 104. The detection segment corresponds to the point neutron source 104, which can be achieved by moving the detection segment directly above the point neutron source 104 and the shaper 110. Through the shaper 110 and the segmented calibration method, the longer detection segment is calibrated using the point neutron source 104.

[0068] In this embodiment, the detector can be moved along the first direction by either the first slide 107 or the second slide 109, or both the first slide 107 and the second slide 109. Moving the detector along the first direction by the first slide 107 and the second slide 109 can improve displacement accuracy and movement range. For example, the displacement accuracy of the detector along the first direction can be less than or equal to 1 millimeter.

[0069] In this embodiment, the sensitive area 201 of the detector is divided into multiple detection segments to achieve segmented calibration of the detector, thereby enabling calibration of a longer detector.

[0070] In this embodiment, the specific structure of the second slide 109 is not limited, as long as it can move the detector. For example, an electric push rod can be used.

[0071] In some embodiments, the thermal neutron fluence of the thermal neutron field formed by the point neutron source 104 is 1 cm⁻¹. -2 ·s -1 Up to 100cm -2 ·s -1 .

[0072] In this embodiment, the thermal neutron fluence rate of the thermal neutron field formed by the point neutron source 104 is 1 cm⁻¹. -2 ·s -1 Up to 100cm -2 ·s -1 That is, the calibration device 100 is suitable for low-range delayed neutron detectors, facilitating on-site calibration. The thermal neutron energy is ≤0.5 eV.

[0073] In one possible implementation, the thermal neutron fluence of the thermal neutron field formed by the point neutron source 104 is 1 cm⁻¹. -2 ·s -1 5cm -2 ·s -1 10cm -2 ·s -1 50cm -2 ·s -1 Or 100cm -2 ·s -1 .

[0074] As shown in the figure, in one possible implementation, the calibration device 100 further includes a control device 800. The control device 800 includes a processor 802 and a memory 804 storing program instructions. The processor 802 is configured to execute the delayed neutron detector calibration method described below when executing the program instructions.

[0075] Combination Figure 9 As shown, according to a second aspect of the embodiments of this application, a method for calibrating a delayed neutron detector is proposed. The method uses a delayed neutron detector calibration device 100 as described above to determine the calibration factor of a calibration detector 200 for segmented calibration of the delayed neutron detector. The sensitive area of ​​a standard detector is divided into multiple standard detection segments. The sensitive area 201 of the calibration detector 200 is divided into multiple calibration detection segments. Each calibration detection segment corresponds one-to-one with a multiple standard detection segment. A calibration detector refers to a delayed neutron detector that needs to be calibrated. A standard detector refers to a detector that can be used to calibrate a delayed neutron detector; the specific structures of the standard detector and the calibration detector 200 are not limited. The calibration method includes the following steps: S901, The processor obtains the preset coordinates of the preset calibration position relative to the point neutron source, as well as the thermal neutron flux rate at the preset coordinates.

[0076] In this embodiment, combined with Figure 7 As shown, a coordinate system can be established with the point neutron source 104 as the origin O, with the X-axis extending in the left-right direction (first direction) and the Y-axis extending in the up-down direction (second direction). The preset calibration position can be located directly above the point neutron source 104. The preset coordinates of the preset calibration position relative to the point neutron source 104 are the coordinates of the preset calibration position within this coordinate system. By obtaining the preset coordinates of the preset calibration position, position parameters are provided for the movement of the standard detector and the calibration detector 200.

[0077] In this embodiment, the thermal neutron fluence rate at a preset coordinate is obtained, that is, the thermal neutron fluence rate at a preset calibration position is obtained, so as to obtain the calibration factor of the calibration detector 200 under the thermal neutron fluence rate corresponding to the preset calibration position.

[0078] In this embodiment, multiple preset calibration positions can be set, and these multiple preset calibration positions are arranged at intervals directly above the point neutron source 104. Each of the multiple preset calibration positions corresponds one-to-one with a different thermal neutron fluence rate.

[0079] In one possible implementation, the thermal neutron fluence rate (Φ) at a preset calibration location is measured using a He-3 sphere detector to provide an accurate thermal neutron fluence rate measurement.

[0080] S902, The processor controls the moving component to move the standard detector to the preset coordinates according to the preset coordinates, and obtains multiple first readings that correspond one-to-one with multiple standard detection segments.

[0081] In this embodiment, the moving component 106 is controlled to operate. Specifically, the standard detector can be moved by the first slide 107 and the lifting platform 108 to a preset coordinate position. That is, the standard detector is moved to a preset calibration position. For example, as... Figure 7 As shown, firstly, the first slide 107 is controlled to move, causing the first slide 107 to move the standard detector along the X-axis, moving the standard detector to the preset horizontal coordinate position. Then, the lifting platform 108 is controlled to move, causing the lifting platform 108 to move the standard detector along the Y-axis, moving the standard detector to the preset coordinate position.

[0082] In this embodiment, the sensitive area of ​​the standard detector is divided into multiple standard detection segments to achieve segmented calibration of the calibration detector 200. When different standard detection segments move to preset calibration positions, readings of the standard detector are acquired to obtain multiple first readings corresponding one-to-one with the multiple standard detection segments.

[0083] In some embodiments, the step of controlling the moving component 106 to move a standard detector to a preset coordinate and obtaining multiple first readings corresponding to multiple standard detection segments includes: controlling the moving component 106 to move a standard detection segment closer to the standard detector to a preset coordinate, and obtaining a first reading corresponding to the standard detection segment; obtaining a first translational distance of the standard detector; and controlling the moving component 106 to move the standard detector sequentially along a first direction by a first translational distance, so that the remaining standard detection segments are sequentially moved to the preset coordinate and the first readings corresponding to the remaining standard detection segments are obtained, thereby obtaining multiple first readings corresponding to multiple standard detection segments.

[0084] In this embodiment, based on preset coordinates, the moving component 106 is controlled to move the standard detection segment closest to the standard detector to the preset coordinates, thereby moving one of the multiple standard detection segments located at the end to the preset calibration position. For example, a marker can be placed at the middle position of the standard detection segment, and an identification sensor can be placed in the housing 101. When the marker on the standard detection segment moves to the preset coordinates, the identification sensor can recognize the marker, indicating that the standard detection segment has moved to the preset calibration position. For example, if the preset calibration position is located directly above the point neutron source 104, when the standard detection segment is moved to the preset calibration position directly above the point neutron source 104, the reading of the standard detector is obtained, that is, the first reading corresponding to the standard detection segment is obtained.

[0085] In this embodiment, the sensitive area of ​​the standard detector is divided into multiple standard detection segments, and the preset length of each standard detection segment can be determined. The preset length of each standard detection segment can be a first translation distance. After one of the standard detection segments located at the end moves to the preset calibration position, the first slide 107 and / or the second slide 109 are controlled to continue operating, driving the standard detector to move along the X-axis direction (first direction). After moving one first translation distance, the next standard detection segment can be moved to the preset calibration position, and then the reading of the standard detector is obtained, that is, the first reading corresponding to the standard detection segment is obtained. In this way, the standard detector is driven to move sequentially along the first direction, moving one first translation distance each time, so as to move the remaining standard detection segments sequentially to the preset coordinates, and obtain the first reading corresponding to the remaining standard detection segments one by one, until the last standard detection segment moves to the preset coordinates, and a total of multiple first readings corresponding to multiple standard detection segments are obtained, providing data for determining the calibration factor of the calibration detector 200 under thermal neutron fluence rate.

[0086] In one possible implementation, for each standard detection segment, multiple readings (e.g., three) can be acquired, and the average of the multiple readings can be calculated to obtain the corresponding first reading, thereby improving the accuracy of acquiring the first reading corresponding to the standard detection segment.

[0087] S903. The processor controls the moving component to move the calibration detector to the preset coordinates according to the preset coordinates, and obtains multiple second readings that correspond one-to-one with multiple calibration detection segments. The multiple second readings correspond one-to-one with multiple first readings.

[0088] In this embodiment, the moving component 106 is controlled to operate according to preset coordinates to move the calibration detector 200 to the preset coordinates and obtain multiple second readings corresponding one-to-one with multiple calibration detection segments. This process is basically the same as the process of the standard detector described above, except that the standard detector is replaced by the calibration detector 200.

[0089] In this embodiment, multiple calibration probe segments correspond one-to-one with multiple standard probe segments. Specifically, the number of standard probe segments may be the same as the number of calibration probe segments, and the preset length of the standard probe segments may be the same as the preset length of the corresponding calibration probe segments, so that multiple second readings correspond one-to-one with multiple first readings. By comparing the readings at the standard probe segments with the readings at the corresponding calibration probe segments, each calibration probe segment is calibrated, thereby achieving segmented calibration of the calibration detector 200.

[0090] In some embodiments, the step of controlling the moving component 106 to move the calibration detector 200 to the preset coordinates and obtaining multiple second readings corresponding to multiple calibration detector segments includes: controlling the moving component 106 to move the calibration detector segment closest to the calibration detector 200 to the preset coordinates and obtaining the second reading corresponding to the calibration detector segment; obtaining a second translation distance of the calibration detector 200; and controlling the moving component 106 to move the calibration detector 200 sequentially along a first direction by the second translation distance, thereby moving the remaining calibration detector segments sequentially to the preset coordinates and obtaining the second readings corresponding to the remaining calibration detector segments, thus obtaining multiple second readings corresponding to multiple calibration detector segments.

[0091] In this embodiment, based on preset coordinates, the moving component 106 is controlled to move the calibration probe segment closest to the calibration detector 200 to the preset coordinates, thereby moving one of the multiple calibration probe segments located at the end to the preset calibration position. For example, a marker can be set at the middle position of the calibration probe segment, and an identification sensor can be set in the housing 101. When the marker on the calibration probe segment moves to the preset coordinates, the identification sensor can identify the marker, indicating that the calibration probe segment has moved to the preset calibration position. For example, if the preset calibration position is located directly above the point neutron source 104, when the calibration probe segment is moved to the preset calibration position directly above the point neutron source 104, the reading of the calibration detector 200 is obtained, that is, the second reading corresponding to the calibration probe segment is obtained.

[0092] In this embodiment, the sensitive area 201 of the calibration detector 200 is divided into multiple calibration detection segments, and the preset length of each calibration detection segment can be determined. The preset length of each calibration detection segment can be a second translation distance. After one of the calibration detection segments located at the end moves to the preset calibration position, the first slide 107 and / or the second slide 109 are controlled to continue operating, driving the calibration detector 200 to move along the X-axis direction (first direction). Each time it moves by a second translation distance, the next calibration detection segment can be moved to the preset calibration position, and then the reading of the calibration detector 200 is obtained, that is, the second reading corresponding to the calibration detection segment is obtained. In this way, the calibration detector 200 is driven to move sequentially along the first direction, each time moving by a second translation distance, so as to move the remaining calibration detection segments sequentially to the preset coordinates, and obtain the second reading corresponding to the remaining calibration detection segments one by one, until the last calibration detection segment moves to the preset coordinates, and a total of multiple second readings corresponding to multiple calibration detection segments are obtained, providing data for determining the calibration factor of the calibration detector 200 under thermal neutron fluence rate.

[0093] For example, in combination Figure 8 As shown, Figure 8 The F arrow in the diagram indicates the direction of movement of the calibration detector 200. The sensitive area 201 of the calibration detector 200 is divided into four calibration detection segments, designated as the first calibration detection segment 202, the second calibration detection segment 203, the third calibration detection segment 204, and the fourth calibration detection segment 205, all of equal length. The second translation distance is the length of each calibration detection segment. Figure 8M1 in the diagram illustrates the uniform thermal neutron field formed by the combined action of the point neutron source 104 and the shaper 110. Based on preset coordinates, the moving component 106 is controlled to move the first calibration detector segment 202 to the preset coordinates, allowing the uniform thermal neutron field formed by the combined action of the point neutron source 104 and the shaper 110 to scan the first calibration detector segment 202 and obtain the reading of the calibration detector 200, thus obtaining the reading corresponding to the first calibration detector segment 202. The first slide 107 and / or the second slide 109 are controlled to continue operating, moving the calibration detector 200 a second translation distance along the direction of arrow F, moving the second calibration detector segment 203 to the preset coordinates, allowing the uniform thermal neutron field formed by the combined action of the point neutron source 104 and the shaper 110 to scan the first calibration detector segment 202 and obtain the reading corresponding to the first calibration detector segment 202. Figure 8 The M1 in the middle scans the second calibration detector segment 203 and obtains the reading of the calibration detector 200, that is, the reading corresponding to the second calibration detector segment 203. The first slide 107 and / or the second slide 109 are controlled to continue to run, driving the calibration detector 200 to move another second translation distance along the direction of arrow F, moving the third calibration detector segment 204 to the preset coordinates, so that the uniform thermal neutron field formed by the synergistic action of the point neutron source 104 and the shaper 110 ( Figure 8 The third calibration detector segment 204 is scanned by M1, and the reading of the calibration detector 200 is obtained, which is the reading three corresponding to the third calibration detector segment 204. The first slide 107 and / or the second slide 109 are controlled to continue running, driving the calibration detector 200 to move another second translation distance along the direction of arrow F, moving the fourth calibration detector segment 205 to the preset coordinates, so that the uniform thermal neutron field formed by the synergistic action of the point neutron source 104 and the shaper 110 scans the fourth calibration detector segment 205, and the reading of the calibration detector 200 is obtained, which is the reading four corresponding to the fourth calibration detector segment 205. After scanning all four calibration detector segments by the uniform thermal neutron field formed by the synergistic action of the neutron source and the shaper 110, the entire calibration detector 200 is scanned. This is equivalent to scanning the entire calibration detector 200 by a small uniform thermal neutron field (such as M1). Figure 8 Multiple scans were performed on M1 to form a large uniform thermal neutron field (as shown in the image). Figure 8 As shown in M), the entire calibration detector 200 is scanned to achieve on-site calibration of the detector and improve calibration accuracy. In this example, the first calibration detector segment 202, the second calibration detector segment 203, the third calibration detector segment 204, and the fourth calibration detector segment 205, along with the corresponding readings one, two, three, and four, can be understood as the aforementioned multiple second readings that correspond one-to-one with multiple calibration detector segments.

[0094] In one possible implementation, multiple readings (e.g., three) can be acquired for each calibration probe segment. The corresponding second reading is obtained by calculating the average of the multiple readings, thereby improving the accuracy of acquiring the second reading corresponding to the calibration probe segment.

[0095] S904 The processor determines the calibration factor of the calibration detector at the thermal neutron fluence rate based on multiple first readings and multiple second readings.

[0096] In this embodiment, multiple first readings and multiple second readings correspond one-to-one. By using multiple first readings and multiple second readings, the calibration factor of the calibration detector 200 at the thermal neutron flux rate is determined, so as to realize the calibration of the delayed neutron detector on site.

[0097] In some embodiments, the step of determining the calibration factor of the calibration detector 200 at a thermal neutron fluence rate based on a plurality of first readings and a plurality of second readings includes: calculating the proportional relationship between the second readings and the corresponding first readings to obtain a plurality of segmented calibration factors; and calculating the average value of the plurality of segmented calibration factors to obtain the calibration factor of the calibration detector 200 at a thermal neutron fluence rate.

[0098] Specifically, the segmented calibration factor C k According to the following formula: C k =K m / K s Calculate by multiplying by 100%. Where K... s For the first reading, K m To be with K s The corresponding second reading. The proportional relationship between the second reading and the corresponding first reading is calculated using the segmented calibration factor formula to obtain the segmented calibration factor. Each segmented calibration factor reflects the performance of the corresponding calibration probe segment. Multiple segmented calibration factors are obtained by calculating the proportional relationships between multiple second readings and their corresponding multiple first readings.

[0099] Furthermore, by calculating the average of multiple segmented calibration factors, the calibration factor of the calibration detector 200 at the thermal neutron flux rate is obtained.

[0100] Since multiple preset calibration positions can be set, these positions are arranged at intervals directly above the point neutron source 104. Each preset calibration position corresponds one-to-one with a different thermal neutron fluence rate. After obtaining the calibration factor of the calibrated detector 200 at one of the thermal neutron fluence rates, the preset coordinates of the next preset calibration position are obtained. Steps S901 to S904 are repeated to obtain the calibration factor of the calibrated detector 200 at the next thermal neutron fluence rate. This process is repeated to obtain multiple calibration factors of the calibrated detector 200 at multiple thermal neutron fluence rates, enabling on-site calibration of the delayed neutron detector.

[0101] The calibration device 100 in this embodiment is easy to operate and can generate a thermal neutron field that meets the requirements for calibrating delayed neutron detectors. Furthermore, through a segmented calibration method, it can accommodate detectors of longer dimensions, enabling on-site calibration and providing reliable metrological assurance for the safe operation of reactors.

[0102] Combination Figure 10 As shown, this disclosure provides a control device 800, including a processor 802 and a memory 804 storing program instructions. The processor 802 is configured to execute a delayed neutron detector calibration method as described in any of the preceding embodiments when executing the program instructions.

[0103] This disclosure provides a control device 800, the structure of which is as follows: Figure 10 As shown, the system includes a processor 802 and a memory 804, and may also include a communication interface 806 and a bus 808. The processor 802, communication interface 806, and memory 804 can communicate with each other via the bus 808. The communication interface 806 can be used for information transmission. The processor 802 can call logical instructions in the memory 804 to execute the delayed neutron detector calibration method of the above embodiment.

[0104] The memory 804, as a computer-readable storage medium, can be used to store software programs and computer-executable programs, such as the program instructions / modules corresponding to the methods in the embodiments of this disclosure. The processor 802 executes functional applications and data processing by running the program instructions / modules stored in the memory 804, thereby implementing the delayed neutron detector calibration method in the above method embodiments. Therefore, it possesses all the beneficial effects of the above embodiments, which will not be elaborated further here.

[0105] The memory 804 may include a program storage area and a data storage area. The program storage area may store the operating system and application programs required for at least one function; the data storage area may store data created based on the use of the terminal device. Furthermore, the memory 804 may include a high-speed random access memory 804, and may also include non-volatile memory 804.

[0106] This disclosure provides a computer-readable storage medium storing computer-executable instructions configured to perform the aforementioned delayed neutron detector calibration method.

[0107] The aforementioned computer-readable storage medium may be a transient computer-readable storage medium or a non-transitory computer-readable storage medium.

[0108] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application. The above are merely preferred embodiments of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this application, and these improvements and modifications should also be considered within the protection scope of this application.

Claims

1. A calibration device for a delayed neutron detector, characterized in that, include: The enclosure defines separate working and mounting chambers; A point neutron source is disposed within the mounting cavity; A movable component is disposed in the housing, and the connecting end of the movable component extends into the working chamber and is connected to the detector. The moving component is used to move the detector relative to the point neutron source, so that different positions of the detector correspond to the point neutron source, and to obtain the readings of the detector for segmented calibration of the detector. The moving component includes: A first slide is provided in the housing; A lifting platform is slidably disposed on the first sliding platform, and the lifting platform includes the connecting end; Wherein, the first slide is used to drive the lifting platform to move so as to drive the detector to move along a first direction, and the lifting platform is used to drive the detector to move along a second direction, the second direction being perpendicular to the first direction; The moving component also includes: A second slide is disposed at the connecting end, and the detector is disposed on the second slide. The second slide is used to drive the detector to move along the first direction. Wherein, when the sensitive area of ​​the detector is divided into multiple detection segments, the first slide and / or the second slide are used to move the detector so that different detection segments correspond to the point neutron source.

2. The calibration device according to claim 1, characterized in that, Also includes: A shaper is disposed on the outside of the point neutron source on the side facing the detector, and is used to adjust the uniformity of the thermal neutron field formed by the point neutron source; The shaper has an axisymmetric structure. The axis of the shaper passes through the point neutron source and extends along the direction from the point neutron source to the detector. The distance between the sidewall of the shaper and the axis of the shaper gradually decreases.

3. The calibration device according to claim 1, characterized in that, The working chamber of the housing encloses at least a portion of the mounting cavity. The working chamber is filled with a filling medium for slowing down and shielding the fast neutrons generated by the point neutron source. The filling medium includes water.

4. The calibration apparatus according to any one of claims 1 to 3, characterized in that, The thermal neutron fluence of the thermal neutron field formed by the point neutron source is 1 cm⁻¹. -2 ·s -1 Up to 100cm -2 ·s -1 .

5. A method for calibrating a delayed neutron detector, comprising using the delayed neutron detector calibration apparatus as described in any one of claims 1 to 4 to determine the calibration factor of the detector, characterized in that, The sensitive area of ​​the standard detector is divided into multiple standard detection segments, and the sensitive area of ​​the calibration detector is divided into multiple calibration detection segments. Each calibration detection segment corresponds one-to-one with one of the multiple standard detection segments. The calibration method includes the following steps: Obtain the preset coordinates of the preset calibration position relative to the point neutron source, and the thermal neutron fluence at the preset coordinates; According to the preset coordinates, control the operation of the moving component to move the standard detector to the preset coordinates and obtain multiple first readings that correspond one-to-one with the multiple standard detection segments; According to the preset coordinates, the moving component is controlled to move the calibration detector to the preset coordinates, and multiple second readings corresponding to multiple calibration detection segments are obtained, with the multiple second readings corresponding to multiple first readings. The calibration factor of the calibration detector at the thermal neutron fluence rate is determined based on a plurality of first readings and a plurality of second readings.

6. The calibration method according to claim 5, characterized in that, The steps of controlling the moving component to move the standard detector to the preset coordinates and obtaining multiple first readings corresponding one-to-one with the multiple standard detection segments include: According to the preset coordinates, the moving component is controlled to move the standard detection segment near the standard detector to the preset coordinates, and a first reading corresponding to the standard detection segment is obtained. Obtain the first translational distance of the standard detector; Based on the first translation distance, the moving component is controlled to move the standard detector sequentially along the first direction by the first translation distance, so that the remaining standard detection segments are sequentially moved to the preset coordinates, and a first reading corresponding to each of the remaining standard detection segments is obtained, thereby obtaining multiple first readings corresponding to multiple standard detection segments.

7. The calibration method according to claim 5, characterized in that, The step of controlling the moving component to move the calibration detector to the preset coordinates and obtaining multiple second readings corresponding one-to-one with the multiple calibration detector segments includes: According to the preset coordinates, the moving component is controlled to move the calibration detection segment near the calibration detector to the preset coordinates, and a second reading corresponding to the calibration detection segment is obtained. Obtain the second translation distance of the calibration detector; Based on the second translation distance, the moving component is controlled to move the calibration detector sequentially along the first direction by the second translation distance, so as to move the remaining calibration detection segments sequentially to the preset coordinates, and obtain the second reading corresponding to the remaining calibration detection segments one by one, and then obtain multiple second readings corresponding to multiple calibration detection segments one by one.

8. The calibration method according to claim 5, characterized in that, The step of determining the calibration factor of the calibration detector at the thermal neutron fluence rate based on a plurality of first readings and a plurality of second readings includes: Based on multiple first readings and multiple second readings, the proportional relationship between the second reading and the corresponding first reading is calculated to obtain multiple segmented calibration factors; The average value of the multiple segmented calibration factors is calculated to obtain the calibration factor of the calibration detector at the thermal neutron fluence rate.

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