Calibration device and calibration method for delayed neutron monitor

Abstract

The embodiment of the invention provides a delayed neutron monitor calibration device and calibration method, and a delayed neutron monitor calibration device. The first beam intensity detection device comprises a penetration type ionization chamber, the penetration type ionization chamber is arranged between the delayed neutron calibration source and the accelerator along the emission direction of the beam, and the penetration type ionization chamber is arranged close to an emission port of the accelerator, so that the beam passes through the penetration type ionization chamber; the second beam intensity detection device comprises a finger-type ionization chamber, the finger-type ionization chamber is arranged between the delayed neutron calibration source and the accelerator in the beam emitting direction, the finger-type ionization chamber is arranged close to the first channel, and the finger-type ionization chamber can move in the first direction. According to the delayed neutron monitor calibration device provided by the embodiment of the invention, accurate calibration of the delayed neutron calibration source in the beam field can be realized, the stability and efficiency of beam irradiation are improved, and the calibration precision of the delayed neutron monitor is further improved.

Description

Technical Field

[0001] The present application relates to a delayed neutron monitoring technology, and in particular to a delayed neutron monitor calibration device and a calibration method. Background Art

[0002] During the operation of nuclear reactors, the main accident risk comes from the leakage of radioactive materials caused by structural damage. Monitoring delayed neutrons in reactor loop water is one of the effective methods to detect whether fuel elements are damaged. In the related art, a delayed neutron calibration source is used to simulate radiation conditions, but there is a lack of a delayed neutron monitor calibration device for calibrating the delayed neutron monitor. Summary of the invention

[0003] In view of this, an embodiment of the present application provides a delayed neutron monitor calibration device and a calibration method, which can calibrate the delayed neutron monitor in a beam field.

[0004] To achieve the above-mentioned purpose, the first aspect of the embodiment of the present application provides a delayed neutron monitor calibration device, comprising:

[0005] A delayed neutron calibration source, comprising a shielding portion, a containing device and an accelerator; a first containing cavity and a first channel connected to the first containing cavity are formed inside the shielding portion, the first containing cavity is used to contain a reaction target, and the shielding portion can shield radiation; the containing device is arranged in the first containing cavity, and is used to contain the reaction target; at least part of the detector is arranged in the first containing cavity, and the detector is used to detect the neutron count rate in the first containing cavity; the beam emitted by the accelerator can pass through the first channel to irradiate the reaction target;

[0006] A monitor assembly, wherein the monitor assembly is disposed on the shielding portion, and at least a portion of the monitor assembly extends into the first accommodating cavity, and is used to detect a neutron count rate in the first accommodating cavity;

[0007] a first beam intensity detection device, the first beam intensity detection device comprising a penetrating ionization chamber, the penetrating ionization chamber being arranged between the delayed neutron calibration source and the accelerator along the emission direction of the beam, the penetrating ionization chamber being arranged close to the emission port of the accelerator so that the beam passes through the penetrating ionization chamber;

[0008] A second beam intensity detection device, the second beam intensity detection device comprises a finger-type ionization chamber, the finger-type ionization chamber is arranged between the delayed neutron calibration source and the accelerator along the emission direction of the beam, the finger-type ionization chamber is arranged close to the first channel, and the finger-type ionization chamber can move along a first direction, wherein the first direction, the emission direction of the beam, and the height direction of the delayed neutron monitor calibration device intersect.

[0009] In one embodiment, the shielding portion has a second channel extending along the height direction of the monitor calibration device, the second channel is connected to the first accommodating cavity, the monitor assembly includes a first driving assembly and a detection member, the detection member passes through the second channel and extends into the first accommodating cavity, and the first driving assembly is used to drive the detection member to extend into or away from the first accommodating cavity along the height direction of the monitor calibration device.

[0010] In one embodiment, the first beam intensity detection device includes a mounting member and a telescopic arm, one end of the telescopic arm is connected to the mounting member, and the other end is connected to the penetration type ionization chamber, the mounting member has an avoidance hole arranged opposite to the emission port of the accelerator, and the telescopic arm can drive the penetration type ionization chamber to approach or move away from the avoidance hole.

[0011] In one embodiment, the telescopic arm includes a first rotating member and a second rotating member, wherein the first end of the first rotating member is rotatably connected to the mounting member, the second end of the first rotating member is rotatably connected to the first end of the second rotating member, and the second rotating member is rotatably connected to the penetration type ionization chamber.

[0012] In one embodiment, the second beam intensity detection device includes a second driving assembly, and the second driving assembly is at least capable of driving the finger-type ionization chamber to move along the first direction.

[0013] In one embodiment, the finger-type ionization chamber moves a distance of not less than 300 mm along the first direction.

[0014] In one embodiment, the delayed neutron calibration source includes a third driving component, the shielding part is arranged on the third driving component, and the third driving component can at least drive the shielding part to move along the height direction of the monitor calibration device, the emission direction of the beam and the first direction.

[0015] A second aspect of the embodiments of the present application provides a delayed neutron monitor calibration method, which is applied to the delayed neutron monitor calibration device described in any embodiment of the present application, wherein the detection component includes a calibration detector and a detector to be tested.

[0016] The delayed neutron monitor calibration method comprises:

[0017] Adjusting the delayed neutron calibration source to a position of maximum beam intensity;

[0018] Controlling the operation of the delayed neutron calibration source;

[0019] Controlling the calibration detector to detect delayed neutrons to obtain a first counting rate;

[0020] Controlling the detector to be tested to detect delayed neutrons to obtain a second counting rate;

[0021] The detector under test is calibrated.

[0022] In one embodiment, adjusting the delayed neutron calibration source to a maximum beam intensity position includes:

[0023] Controlling the accelerator to emit a beam;

[0024] controlling the first beam intensity detection device to measure the intensity of the beam;

[0025] Controlling the second beam intensity detection device to measure the maximum beam intensity position of the beam;

[0026] The delayed neutron calibration source is adjusted to move to the maximum beam intensity position.

[0027] In one embodiment, calibrating the detector to be tested includes:

[0028] calculating an emissivity of the delayed neutron calibration source according to the first counting rate;

[0029] The response value of the detector to be tested is calculated according to the second counting rate and the emission rate.

[0030] In one embodiment, the controlling the delayed neutron calibration source includes:

[0031] Filling the reaction target in the containing device;

[0032] Setting the beam intensity of the accelerator to a first beam intensity;

[0033] The beam of the accelerator is controlled to irradiate the reaction target.

[0034] In one embodiment, controlling the beam of the accelerator to irradiate the reaction target comprises:

[0035] Controlling the beam of the accelerator to irradiate the reaction target to generate precursor nuclei;

[0036] When the precursor nucleus reaches a saturation state, controlling the beam of the accelerator to stop irradiating the reaction target;

[0037] The delayed neutron calibration source is left to stand until the prompt neutrons in the containing device disappear.

[0038] The delayed neutron monitor calibration device provided in the embodiment of the present application is centered on a delayed neutron calibration source to generate delayed neutrons. The monitor component detects the neutron count rate to obtain key calibration data. The first beam intensity detection device and the second beam intensity detection device are located at different positions. The first beam intensity detection device is close to the accelerator emission end to capture the source beam information, and the second beam intensity detection device can be flexibly moved to detect the maximum beam position. In this way, accurate calibration of the delayed neutron calibration source in the beam field can be achieved, thereby improving the stability and efficiency of beam irradiation, and thus improving the calibration accuracy of the delayed neutron monitor. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic diagram of the structure of a delayed neutron monitor calibration device in an embodiment of the present application;

[0040] Figure 2 This is a schematic structural diagram of another perspective of the delayed neutron monitor calibration device in the embodiment of the present application;

[0041] Figure 3 for Figure 1 A schematic diagram of the structure of the delayed neutron calibration source and monitor assembly;

[0042] Figure 4 for Figure 1 A schematic structural diagram of a first beam intensity detection device in;

[0043] Figure 5 for Figure 1 A schematic structural diagram of a second beam intensity detection device in FIG.

[0044] Figure 6 This is a flow chart of a delayed neutron monitor calibration method in an embodiment of the present application.

[0045] Description of Reference Numerals

[0046] 100. Delayed neutron monitor calibration device; 10. Delayed neutron calibration source; 1. Shielding portion; 11. First accommodating chamber; 12. First channel; 13. Second channel; 2. Accommodating device; 3. Accelerator; 20. Monitor assembly; 21. First driving assembly; 22. Detection member; 30. First beam intensity detection device; 31. Penetration type ionization chamber; 32. Mounting member; 321. Avoidance hole; 33. Telescopic arm; 331. First rotating member; 332. Second rotating member; 40. Second beam intensity detection device; 41. Finger-type ionization chamber; 42. Second driving assembly. DETAILED DESCRIPTION

[0047] It should be noted that, in the absence of conflict, the embodiments in this application and the technical features in the embodiments can be combined with each other, and the detailed description in the specific implementation method should be understood as an explanation of the purpose of this application and should not be regarded as an improper limitation on this application.

[0048] In the description of the embodiments of the present application, it should be noted that the terms "transmission direction of the ray", "height direction", "first direction", "second direction", etc. indicate the orientation or position relationship based on the orientation or position relationship shown in the drawings. These orientation terms are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the embodiments of the present application. The present application will be further described in detail below in conjunction with the drawings and specific embodiments.

[0049] The present application embodiment provides a delayed neutron monitor calibration device 100, see Figures 1 to 5 The delayed neutron monitor calibration device 100 includes a delayed neutron calibration source 10, a monitor assembly 20, a first beam intensity detection device 30 and a second beam intensity detection device 40. The delayed neutron calibration source 10 includes a shielding portion 1, a containing device 2 and a detector. A first containing cavity 11 and a first channel 12 connected to the first containing cavity 11 are formed inside the shielding portion 1. The first containing cavity 11 is used to contain a reaction target, and the shielding portion 1 can shield radiation. The containing device 2 is arranged in the first containing cavity 11 to contain a reaction target. At least part of the detector is arranged in the first containing cavity 11, and the detector is used to detect the neutron count rate in the first containing cavity 11. The beam emitted by the accelerator 3 can pass through the first channel 12 to irradiate the reaction target. The monitor assembly 20 is arranged in the shielding portion 1, and at least part of the monitor assembly 20 extends into the first containing cavity 11 to detect the neutron count rate in the first containing cavity 11. The first beam intensity detection device 30 includes a penetration type ionization chamber 31, which is arranged between the delayed neutron calibration source 10 and the accelerator 3 along the emission direction of the beam, and the penetration type ionization chamber 31 is arranged close to the emission port of the accelerator 3 so that the beam passes through the penetration type ionization chamber 31. The second beam intensity detection device 40 includes a finger type ionization chamber 41, which is arranged between the delayed neutron calibration source 10 and the accelerator 3 along the emission direction of the beam, and the finger type ionization chamber 41 is arranged close to the first channel 12, and the finger type ionization chamber 41 can move along the first direction, wherein the first direction, the emission direction of the beam, and the height direction of the delayed neutron monitor calibration device 100 intersect.

[0050] The delayed neutron calibration source 10 is a device specially used for calibrating and detecting neutron-related measuring equipment. Delayed neutrons refer to neutrons emitted when certain radioactive nuclides in nuclear fission products decay. Unlike prompt neutrons, they are not generated at the moment of fission, but are emitted after a certain time delay. The delayed neutron calibration source 10 can accurately provide such neutrons, which are used to calibrate the accuracy of detection equipment when measuring delayed neutrons.

[0051] The delayed neutron calibration source 10 comprises a shielding portion 1 , a containing device 2 , a detector and an accelerator 3 .

[0052] The specific material of the shielding part 1 is not limited here. The material has strong absorption and scattering capabilities for radiation, and its function is to block the internal radiation from leaking outward to prevent harm to the surrounding environment and operators. At the same time, it isolates external interference radiation from entering the interior, ensures that the calibration source is not disturbed, and maintains a stable radiation environment.

[0053] Exemplarily, the shielding part 1 is made of hydrogen-containing material, for example, the shielding part 1 is a boron-containing polyethylene cylinder with a diameter of 240 mm and a height of 460 mm, and a hollow cylinder with a diameter of 80 mm and a height of 300 mm is hollowed out at the center thereof to form the first accommodating chamber 11 .

[0054] The container 2 is usually a high temperature and radiation resistant container made of special ceramics or metal alloys. It provides a stable and closed storage space for the reaction target, ensures that the target is in a predetermined position, enables the accelerator 3 beam to act accurately on the target, and can also contain the products generated by the reaction to prevent them from leaking and contaminating the equipment.

[0055] For example, the container 2 is a titanium alloy cylindrical cup-shaped structure with a 2 mm circular bottom surface, a wall thickness of 2 mm, an inner diameter of the volume part of 50 mm, an outer diameter of 70 mm, and a height of 50 mm. The use of titanium alloy can reduce the corrosion of the solution to the container on the one hand, and reduce the blocking effect on the proton beam inflow and delayed neutron emission on the other hand.

[0056] Exemplarily, sensors are installed on the outside or inside of the containing device 2 to monitor the temperature and pressure in real time to prevent abnormal reactions.

[0057] An accelerator 3 is a device that can accelerate charged particles (such as protons, electrons, etc.) to a high energy state using electric and magnetic fields. The accelerated particle beam has enough energy to hit the reaction target to trigger a nuclear reaction, providing an energy source for producing delayed neutrons. Common types include linear accelerators 3 and cyclotron 3.

[0058] In some embodiments, the accelerator 3 includes a beam deflection magnet to drive the beam to irradiate or deviate from the reaction target.

[0059] Exemplarily, the accelerator 3 is equipped with a beam focusing and shaping system to optimize the beam quality.

[0060] In some embodiments, the accelerator 3 is connected to an intelligent control system to flexibly adjust the beam energy and intensity according to the experimental and calibration requirements. A beam monitor is added downstream to provide real-time feedback on the beam status, and the calibration source can be automatically adjusted according to different states.

[0061] The first accommodating cavity 11 is located inside the shielding part 1 and is a space reserved for accommodating key components such as the device 2 and the detector. It has a regular shape and extends in the height direction to facilitate layout. It can make full use of the internal space of the shielding part 1, so that the components are reasonably distributed and work stably in coordination.

[0062] The first channel 12 is a tubular channel on the shielding part 1, connecting the inside and the outside, for the beam emitted by the accelerator 3 to pass through, accurately guiding the beam to the reaction target. The channel diameter and length are accurately designed according to the beam energy and intensity to prevent beam scattering.

[0063] The reaction target is a key component for generating a nuclear reaction under the irradiation of the particle beam generated by the accelerator 3. The specific composition of the reaction target is not limited here, and is specifically determined according to the nuclear reaction raw materials corresponding to the actual calibration.

[0064] Exemplarily, the reaction target may be radioactive nuclides such as uranium and plutonium that can be used for fission reactions. After being hit by high-energy particles (such as protons and neutrons) generated by the accelerator 3, these nuclides will undergo fission reactions and produce a variety of products including delayed neutrons.

[0065] It should be noted that the reaction target needs to have a certain concentration to ensure that the reaction data can be measured easily. Taking the uranium solution as an example, the uranium concentration should not be less than 0.01g / ml, so that no less than 10 4 The delayed neutron emission rate is on the order of / s.

[0066] Exemplarily, the reaction target may be radioactive nuclides such as uranium and plutonium that can be used for fission reactions. After being hit by high-energy particles (such as protons and neutrons) generated by the accelerator 3, these nuclides will undergo fission reactions and produce a variety of products including delayed neutrons.

[0067] Detectors are instruments that can interact with neutrons and convert information such as neutron flux into electrical signals and counting signals. Common detectors include scintillation detectors and gas detectors. Scintillation detectors use the interaction between neutrons and scintillators to emit light, and then generate electrical signals through photoelectric conversion elements. Gas detectors rely on neutrons to ionize gases to produce ion pairs to record signals, which are used to accurately monitor the number and energy of neutrons in the containment cavity.

[0068] The monitoring instrument assembly 20 is composed of multiple detectors and supporting structures. Some detectors are inserted into the first accommodating cavity 11 and are responsible for detecting the neutron flux, counting rate and other information in the cavity, converting the neutron radiation signal into an electrical signal and a counting signal, and providing first-hand data for subsequent data analysis and calibration.

[0069] The first beam intensity detection device 30 includes a penetrating ionization chamber 31, which is an instrument that uses the principle of ionizing gas using radiation. The penetrating ionization chamber 31 is placed between the delayed neutron calibration source 10 and the accelerator 3, close to the emission port of the accelerator 3, and the beam directly passes through it. It monitors the parameters such as the intensity and stability of the beam emitted by the accelerator 3 in real time, and makes feedback adjustments to ensure the quality of the beam.

[0070] The penetrating ionization chamber 31 is a type of ionization chamber, which is characterized in that the beam can pass directly through the middle, and the internal gas is ionized by the beam to produce ion pairs, which are collected by the collecting electrode to form electrical signals, corresponding to the beam intensity and energy changes, and accurately measuring the initial state of the beam.

[0071] The second beam intensity detection device 40 is equipped with a finger-type ionization chamber 41, which is also used to monitor the beam. It is arranged between the delayed neutron calibration source 10 and the accelerator 3, close to the first channel 12, and can be flexibly moved along the first direction to realize multi-position beam monitoring and comprehensively control the beam status at key transmission nodes.

[0072] The finger-shaped ionization chamber 41 has a finger-like appearance, a compact structure, and is easy to move. When working, the beam ionizes the internal gas, and detects slight changes in the beam with high sensitivity. Moving along the first direction can scan the beam conditions at different points and capture local anomalies.

[0073] Here, the first direction is not specifically limited and can be any direction. For the convenience of description, the first direction of the embodiment of the present application is the direction shown in the drawings.

[0074] The delayed neutron monitor calibration device 100 provided in the embodiment of the present application has a delayed neutron calibration source 10 as its core to generate delayed neutrons. The monitor component 20 detects the neutron count rate to obtain key calibration data. The first beam intensity detection device 30 and the second beam intensity detection device 40 are located at different positions. The first beam intensity detection device 30 is close to the emission end of the accelerator 3 to capture the source beam information, and the second beam intensity detection device 40 can be flexibly moved to detect the maximum beam position. In this way, the delayed neutron calibration source 10 can be accurately calibrated in the beam field, thereby improving the stability and efficiency of beam irradiation, and thus improving the calibration accuracy of the delayed neutron monitor.

[0075] In some embodiments, see Figures 1 to 3The shielding portion 1 has a second channel 13 extending along the height direction of the monitor calibration device, the second channel 13 is connected to the first accommodating chamber 11, the monitor assembly 20 includes a first driving assembly 21 and a detection member 22, the detection member 22 passes through the second channel 13 and extends into the first accommodating chamber 11, and the first driving assembly 21 is used to drive the detection member 22 to extend into or away from the first accommodating chamber 11 along the height direction of the monitor calibration device.

[0076] The second channel 13 is a tubular passage specially opened on the shielding part 1, and its direction is along the height direction of the monitor calibration device. The material is mostly selected from metals or alloys with good radiation shielding performance, such as lead alloy, stainless steel, etc. Its key function is to build a channel for the detection part 22 in the monitor assembly 20 to enter and exit the first accommodating cavity 11, while ensuring that the internal radiation leaks as little as possible, so that the detection part 22 can be smoothly positioned to perform the detection task.

[0077] The first driving component 21 is the power part of the monitoring instrument component 20 , and the specific type of the first driving component 21 is not limited here.

[0078] Exemplarily, the first drive assembly 21 is composed of a motor, a lead screw, a guide rail, and a matching controller. The motor, as a power source, uses a transmission structure such as a lead screw nut pair or a gear rack, combined with the guide rail, to accurately drive the probe 22 to move along the set height direction; the controller is responsible for receiving external instructions, regulating the motor operation state, and achieving flexible position control of the probe 22.

[0079] The detector 22 is the core component of the monitor assembly 20 that actually interacts with neutrons and collects signals. Common types include scintillation detectors, gas detectors, etc. The scintillation detector uses neutrons to hit the scintillator to make it emit light, and then converts the light signal into an electrical signal through a photoelectric conversion element; the gas detector relies on neutrons to ionize the gas, generate ion pairs and collect them to form electrical signals, thereby detecting information such as the flux and energy of neutrons in the first accommodating cavity 11.

[0080] The shielding portion 1 is additionally provided with a second channel 13 along the height direction, which cleverly matches the structure of the monitoring instrument assembly 20; the detection member 22 can enter and exit the first accommodating cavity 11 as needed through the second channel 13, and the first driving assembly 21 gives the detection member 22 the ability to dynamically adjust its position. The staff can remotely or locally control it to allow the detection member 22 to detect neutrons at different heights, meet various experimental and calibration needs, and fully capture the neutron distribution characteristics in the first accommodating cavity 11, while helping to reduce the risk of radiation exposure to the staff.

[0081] In some embodiments, see Figure 1 to Figure 2 , Figure 4The first beam intensity detection device 30 includes a mounting member 32 and a telescopic arm 33. One end of the telescopic arm 33 is connected to the mounting member 32, and the other end is connected to the penetration type ionization chamber 31. The mounting member 32 has an avoidance hole 321 arranged opposite to the emission port of the accelerator 3. The telescopic arm 33 can drive the penetration type ionization chamber 31 to approach or move away from the avoidance hole 321.

[0082] The mounting part 32 is the basic support and positioning part of the first beam intensity detection device 30, and is usually made of metal (such as aluminum alloy, stainless steel), with sufficient structural strength and stability. The mounting part 32 provides a stable connection point for the telescopic arm 33 to ensure that the entire beam monitoring structure is reliably fixed; the avoidance hole 321 is a hole specially opened on the mounting part 32, which accurately corresponds to the emission port of the accelerator 3. Its shape and size are designed according to the beam outlet specifications of the accelerator 3, in order to allow the beam to pass through without obstacles and avoid the mounting part 32 blocking the beam transmission path.

[0083] In some embodiments, a radiation-resistant and high-temperature-resistant ceramic protective ring is added around the edge of the avoidance hole 321. The material is, for example, alumina ceramic, which can not only prevent beam scattering, but also absorb trace leakage radiation, thereby protecting the mounting part 32 body from radiation damage. The surface of the protective ring is polished to reduce the probability of beam reflection and improve the beam transmission efficiency.

[0084] The bottom of the mounting part 32 is designed with support feet with adjustable height and angle. The support feet use shock-absorbing rubber pads and a screw lifting structure to facilitate fine-tuning of the mounting part 32 during the equipment installation and commissioning phase to ensure that the avoidance hole 321 is accurately aligned with the launch port of the accelerator 3; during operation, vibration conduction is weakened to maintain the stability of the monitoring device.

[0085] The telescopic arm 33 is a mechanical structure with adjustable length, and common forms include electric push rods, hydraulic telescopic rods, or telescopic structures composed of a screw nut pair and a guide rail. In this device, one end of the telescopic arm 33 is firmly connected to the mounting member 32, and the other end is connected to the penetrating ionization chamber 31. As a driving component, it can accurately change the distance between the penetrating ionization chamber 31 and the avoidance hole 321 (i.e., the emission port of the accelerator 3), thereby realizing flexible control of the position of the ionization chamber.

[0086] The mounting part 32 lays a solid foundation, and the avoidance hole 321 ensures smooth beam emission. The telescopic arm 33 flexibly pushes the penetrating ionization chamber 31 closer to or away from the emission port of the accelerator 3 as needed. Before the experiment begins, the telescopic arm 33 can be manipulated to bring the ionization chamber close to the emission port to accurately monitor the initial beam; during the process, the position can be dynamically adjusted according to demand to fully control the beam state under different working conditions; it is designed to provide stable and accurate beam data for delayed neutron calibration and ensure the reliability of the entire calibration process.

[0087] In some embodiments, see Figure 1 to Figure 2 , Figure 4 The telescopic arm 33 includes a first rotating member 331 and a second rotating member 332 , wherein a first end of the first rotating member 331 is rotatably connected to the mounting member 32 , a second end of the first rotating member 331 is rotatably connected to a first end of the second rotating member 332 , and the second rotating member 332 is rotatably connected to the penetration type ionization chamber 31 .

[0088] The first rotating member 331 and the second rotating member 332 are key components of the telescopic arm 33 , and are usually made of high-strength metal materials (such as alloy steel, aluminum alloy), and have good mechanical properties and wear resistance.

[0089] The first rotating member 331 is used as a connecting hub. The first end is connected to the mounting member 32 in a rotating manner, and can be flexibly rotated around a specific axis to achieve angle adjustment. The second end is also connected to the second rotating member 332 in a rotating manner, giving the entire telescopic arm 33 structure a variable shape adjustment capability, which is conducive to accurately positioning the position of the penetrating ionization chamber 31.

[0090] The second rotating member 332 is responsible for connecting the first rotating member 331 with the penetrating ionization chamber 31. Its first end is rotatably connected to the first rotating member 331 to form a flexible joint, which can change the relative angle as needed; the second end is firmly rotatably connected to the penetrating ionization chamber 31, which can accurately transmit the movement from the first rotating member 331, and cooperate with the first rotating member 331 to control the ionization chamber to flexibly move and orient at multiple angles in three-dimensional space to meet different beam monitoring needs.

[0091] Rotary connection refers to a connection method in which two parts are connected by connecting parts such as pins, hinges or spherical bearings to achieve a variable relative angle. Compared with fixed connections, rotary connections allow parts to rotate relative to each other, giving the structure flexibility. In this device, with the help of multiple rotary connections, the telescopic arm 33 gets rid of the rigid layout and achieves multi-degree-of-freedom movement, allowing the penetrating ionization chamber 31 to efficiently track and monitor the beam state under complex working conditions.

[0092] The telescopic arm 33 adopts a chain-type rotating structure design, and adopts a combination of a first rotating member 331 and a second rotating member 332 connected in series and both of which are rotatingly connected, to construct a flexible structure similar to a mechanical arm. During installation, each rotating member can easily adjust the initial angle to fit the spatial layout of the equipment; during operation, as the experimental and monitoring requirements change, the first and second rotating members 332 cooperate with each other to drive the penetrating ionization chamber 31 to swing and retract in all directions, accurately approach or move away from the emission port of the accelerator 3, and capture beam information in real time and without blind spots, ensuring the stability and reliability of the beam, and providing a solid data foundation for delayed neutron calibration.

[0093] In some embodiments, see Figure 1 to Figure 2 , Figure 5The second beam intensity detection device 40 includes a second driving assembly 42, and the second driving assembly 42 can at least drive the finger-type ionization chamber 41 to move along the first direction.

[0094] The second driving assembly 42 is a key power and control unit of the second beam intensity detection device 40 , and the specific type of the second driving assembly 42 is not limited herein.

[0095] Exemplarily, the second driving assembly 42 includes a motor, a transmission mechanism, a guide rail, and a controller. The motor is used as a power source to provide driving force; the transmission mechanism is responsible for converting the rotational motion of the motor into linear motion, accurately pushing the finger-type ionization chamber 41 to move; the guide rail is used to guide the movement direction of the ionization chamber to ensure linearity and stability; the controller receives external instructions and adjusts the motor operation state, thereby accurately controlling the movement process of the finger-type ionization chamber 41.

[0096] In the delayed neutron calibration process, the beam characteristics vary with the working conditions. With the help of the second drive component 42, the finger-type ionization chamber 41 is no longer limited to fixed-point monitoring. The second drive component 42 drives the finger-type ionization chamber 41 to move dynamically along the first direction, and can shuttle between different positions as needed to detect the position with the maximum beam intensity, providing a position reference for the subsequent calibration of the delayed neutron calibration source 10. It also provides feasibility for personnel to conduct experimental measurements away from the experimental platform to avoid the risk of radiation exposure to personnel. The specific operation process is as follows:

[0097] The finger-type ionization chamber 41 is placed in the experimental area, at the front end of the entrance. The second driving assembly 42 drives the finger-type ionization chamber 41 to move along the first direction to find the position with the maximum beam current. After the delayed neutron calibration source 10 moves to the maximum beam current position, the second driving assembly 42 drives the finger-type ionization chamber 41 away from the maximum beam current position.

[0098] In some embodiments, the second driving assembly 42 can also drive the finger-type ionization chamber 41 to move in the height direction.

[0099] In some embodiments, Figures 1 to 5 , the finger-type ionization chamber 41 moves a distance of not less than 300 mm along the first direction.

[0100] The lower limit of the moving stroke of the finger-type ionization chamber 41 along the first direction is not less than 300 mm, which means that it has a sufficiently long range of movement in a given direction and can travel at least 300 mm, ensuring that the ionization chamber can cover a large range of key areas of the equipment, avoiding missing important monitoring points due to limited moving range, and comprehensively capturing various changes in the beam transmission process.

[0101] In some embodiments, see Figures 1 to 5The delayed neutron calibration source 10 includes a third driving component, the shielding part 1 is arranged on the third driving component, and the third driving component can at least drive the shielding part 1 to move along the height direction of the monitor calibration device, the beam emission direction and the first direction.

[0102] The third driving component serves as a key power and displacement control unit of the delayed neutron calibration source 10 , and the specific type of the third driving component is not limited herein.

[0103] Exemplarily, the third drive assembly integrates a motor, a transmission mechanism, a guide device, and an intelligent control system. The motor provides the original power, the transmission mechanism is responsible for accurately converting the motor's rotational motion into linear motion or displacement drive in a specific direction, and the guide device ensures that the shielding part 1 moves accurately and stably; the intelligent control system receives external instructions, coordinates the operation of the motor and the transmission components, and accurately controls the movement of the shielding part 1 in a complex three-dimensional space.

[0104] The third driving component drives the free movement in three-dimensional directions, which is conducive to adjusting the relative position of the shielding part 1 in the beam field at any time, adapting to different experimental processes, finding the maximum beam intensity, and improving the reaction efficiency. It also provides feasibility for personnel to conduct experimental measurements away from the experimental platform to avoid the risk of radiation exposure to personnel.

[0105] This application embodiment provides a delayed neutron monitor calibration method, please refer to Figures 1 to 6 The detection element 22 includes a calibration detector and a detector to be tested. The delayed neutron monitor calibration method includes the following steps S101 to S105:

[0106] Step S101, adjusting the delayed neutron calibration source to a maximum beam intensity position.

[0107] Adjust the delayed neutron calibration source 10 to move to this point. This is to allow the calibration source to fully receive the strongest beam, ensure that the reaction target is efficiently excited, and maximize the efficiency of delayed neutron generation; for example, with the help of the third drive component equipped with the delayed neutron calibration source 1010, precise fine-tuning along the height direction and beam emission direction can be achieved to achieve a perfect match between the calibration source and the strongest beam, thereby improving the efficiency of nuclear reactions.

[0108] Step S102, controlling the delayed neutron calibration source to operate.

[0109] The delayed neutron calibration source 10 works to provide delayed neutron detection conditions for the detection element 22 , making preparations for subsequent calibration.

[0110] Step S103, controlling the calibration detector to detect delayed neutrons to obtain a first counting rate.

[0111] A calibrated detector refers to a detector whose response value is already known. By placing the calibrated detector in a delayed neutron radiation environment, the first count rate can be measured by the calibrated detector to obtain the emission rate of the delayed neutrons in the delayed neutron calibration source 10, in preparation for the subsequent calibration of the detector to be tested.

[0112] Step S104, controlling the detector to be tested to detect delayed neutrons to obtain a second counting rate.

[0113] The detector under test refers to a detector whose response value is not yet known, and its response value needs to be measured through the delayed neutron monitor calibration method. Since it is very difficult to directly measure the response value, here, the response value of the detector under test can be measured by combining the second count rate measured by the detector under test with the emissivity calculated by the calibration detector measurement.

[0114] Step S105, calibrating the detector to be tested.

[0115] The response value of the detector to be tested can be obtained by calculation based on the first count rate measured by the calibration detector and the second count rate of the detector to be tested.

[0116] The delayed neutron monitor calibration device 100 provided in the embodiment of the present application has a delayed neutron calibration source 10 as its core to generate delayed neutrons. The monitor component 20 detects the neutron count rate to obtain key calibration data. The first beam intensity detection device 30 and the second beam intensity detection device 40 are located at different positions. The first beam intensity detection device 30 is close to the emission end of the accelerator 3 to capture the source beam information, and the second beam intensity detection device 40 is close to the first channel 12 to check the beam before entering the calibration source state, and can be flexibly moved to monitor the beam in an all-round and dynamic manner. In this way, it is possible to accurately calibrate the delayed neutron calibration source 10 in the beam field, improve the stability and efficiency of beam irradiation, and thus improve the calibration accuracy of the delayed neutron monitor.

[0117] In some embodiments, step S101 includes the following steps:

[0118] Control the accelerator to emit beam.

[0119] Accelerator 3 is a key device for generating high-energy particle beams. Controlling its emission beam is the starting point of the entire calibration process. The characteristics of the beam (such as intensity, energy, particle type, etc.) are directly related to the subsequent nuclear reaction process and the output of delayed neutrons. Accurately setting the parameters of accelerator 3 to enable it to emit a stable beam lays the foundation for subsequent measurement and calibration operations; for example, by adjusting the acceleration voltage, focusing magnetic field and other parameters of accelerator 3, the beam can reach the expected energy and intensity level to meet the basic requirements of the experiment for the beam.

[0120] The first beam intensity detection device is controlled to measure the intensity of the beam.

[0121] The first beam intensity detection device 30 is responsible for real-time monitoring of the beam intensity. Beam intensity is a key indicator for measuring the output performance of the accelerator 3 and the degree of subsequent nuclear reaction excitation. A stable and accurate beam intensity can ensure the repeatability of the reaction and the reliability of the data. The device uses components such as a penetrating ionization chamber 31 to collect the ion pairs generated by the ionized gas when the beam passes through, convert them into electrical signals, and then accurately quantify the beam intensity; once the intensity deviates from the preset value, it can provide timely feedback and adjustments to maintain stable experimental conditions.

[0122] The second beam intensity detection device is controlled to measure the maximum beam intensity position of the beam.

[0123] The second beam intensity detection device 40 focuses on locating the maximum beam intensity position of the beam. Due to the influence of factors such as the accelerator 3 equipment, beam transmission pipeline and surrounding electromagnetic environment, the beam intensity is not uniformly distributed on the transmission path. Knowing the maximum intensity position is crucial to optimizing the working position of the delayed neutron calibration source 10.

[0124] In some embodiments, the second driving assembly 42 can drive the finger-type ionization chamber 41 to move along the first direction, the ejection direction, and the height direction. The finger-type ionization chamber 41 can move in space under the drive of the second driving assembly 42 to explore the position with the maximum beam intensity. After the finger-type ionization chamber 41 determines the position with the maximum beam intensity, the delayed neutron calibration source 10 moves to the position as a whole, so that the beam can enter from the first channel 12 and irradiate the reaction target. When the position of the delayed neutron calibration source 10 is fixed, the second driving assembly 42 drives the finger-type ionization chamber 41 away from the first channel 12.

[0125] In some embodiments, Figure 1 As shown, the second beam intensity detection device 40 and the delayed neutron calibration source 10 are installed together on a base plate, and the base plate is connected to the third driving component, and the third driving component can drive the second beam intensity detection device 40 and the delayed neutron calibration source 10 to move in the height direction, the beam emission direction and the first direction. The second driving component 42 can drive the finger-type ionization chamber 41 to move relative to the base plate along the first direction, and the finger-type ionization chamber 41 is aligned with the first channel 12 in the height direction.

[0126] The steps of searching the position of the maximum beam intensity of the finger-type ionization chamber 41 are as follows:

[0127] First, the second driving assembly 42 drives the finger-type ionization chamber 41 to move to the front end of the first channel 12 along the first direction, and after being aligned with the first channel 12 in the first direction, the relative position of the finger-type ionization chamber 41 and the first channel 12 is maintained constant. Subsequently, the third driving assembly drives the second beam intensity detection device 40 and the delayed neutron calibration source 10 to move as a whole in the height direction, the beam emission direction and the first direction until the finger-type ionization chamber 41 finds the position with the maximum beam intensity and stops moving. Finally, the second driving assembly 42 drives the finger-type ionization chamber 41 to move along the first direction to move away from the first channel 12, so that the beam entering the first channel 12 is the beam with the maximum intensity.

[0128] Adjust the delayed neutron calibration source to move to the maximum beam intensity position.

[0129] According to the maximum beam intensity position measured in the step, the delayed neutron calibration source 10 is adjusted to move to the point. This is to allow the calibration source to fully receive the strongest beam, ensure that the reaction target is efficiently excited, and maximize the efficiency of delayed neutron generation; for example, with the help of the third driving component equipped with the delayed neutron calibration source 10, precise fine-tuning along the height direction and the beam emission direction can be achieved to achieve a perfect match between the calibration source and the strongest beam, thereby improving the efficiency of nuclear reactions.

[0130] In some embodiments, step S105 includes the following steps:

[0131] An emission rate of the delayed neutron calibration source is calculated based on the first count rate.

[0132] It should be noted that the response value here is the ratio of the count rate to the emission rate. The response can be regarded as a constant. Different detectors have different responses. Here, the delayed neutron monitor calibration method is to measure the response value of an unknown detector (i.e., the detector to be tested in the text). The response of the calibrated detector is known. By placing the calibrated detector in the delayed neutron calibration source 10 of the present application, the delayed neutron calibration source 10 provides a stable delayed neutron radiation condition, i.e., the emission rate remains unchanged. The neutron emission rate of the delayed neutron calibration source 10 can be obtained by measuring the first count rate obtained by the calibration detector and the known response of the calibration detector.

[0133] The response value of the detector to be tested is calculated according to the second counting rate and the emission rate.

[0134] The detector to be tested is placed in the delayed neutron calibration source 10. Under the same neutron emission rate, the detector to be tested measures a second count rate. According to the mathematical relationship between the response value and the ratio of the count rate and the emission rate, the response value of the detector to be tested can be obtained to complete the calibration work. Compared with other calibration methods, this method is conducive to reducing the difficulty of calibration.

[0135] In some embodiments, step S102 includes the following steps:

[0136] The reaction target is loaded into the receiving device.

[0137] The reaction target, as the key material basis for the nuclear reaction, is filled in the container 2. The container 2 can provide a stable placement environment for the target, ensure that the subsequent accelerator 3 beam acts accurately on the target, and contain the products generated by the reaction to prevent leakage and contamination of the equipment and the surrounding environment.

[0138] The beam intensity of the accelerator is set to a first beam intensity.

[0139] According to the experimental or calibration requirements, the beam intensity of accelerator 3 is accurately set to the first beam intensity. Beam intensity is a key parameter that affects the intensity of nuclear reactions and the amount of delayed neutrons produced. Different beam intensities will trigger nuclear reactions of different scales. The appropriate first beam intensity setting is a prerequisite for obtaining accurate calibration data later.

[0140] Control the accelerator beam to irradiate the reaction target.

[0141] Control the accelerator 3 to allow the beam of a given intensity to stably and accurately irradiate the reaction target. This step is the core operation to trigger the nuclear reaction and promote the generation of delayed neutrons. The beam interacts with the target, and the atomic nuclei absorb energy to undergo fission and excitation, thereby producing delayed neutrons.

[0142] Here, it should be noted that when measuring the calibration detector and the detector to be tested, the working environment of the delayed neutron calibration source needs to be kept unchanged to ensure that the emission rate of the delayed neutrons is consistent when measuring the calibration detector and the detector to be tested.

[0143] In some embodiments, controlling the beam of the accelerator to irradiate the reaction target comprises:

[0144] The accelerator beam is controlled to irradiate the reaction target to produce precursor nuclei.

[0145] Precursor nuclei are a type of key intermediate product in the nuclear reaction process. When the beam of accelerator 3 accurately irradiates the reaction target according to the set intensity, the target nuclei absorb the energy carried by the beam particles, undergo nuclear reaction processes such as fission and excitation, and then generate a series of unstable nuclides, which are the pioneer nuclei. Taking uranium 235 as a reaction target as an example, under the impact of a high-energy proton beam, the uranium 235 nucleus fissions to produce many fission fragments such as Br-87 and I-137, some of which will further decay into pioneer nuclei, which have the potential to produce delayed neutrons later.

[0146] The delayed neutron precursor nucleus spontaneously decays and fissions, producing a certain number of delayed neutrons, which is the emission rate.

[0147] It should be noted that the emission rate of delayed neutrons is related to many factors. Here, taking uranium as an example, assuming that the uranium concentration is c (kg·m -3 ), the volume of the reaction solution participating in the reaction is V(m 3 ), proton beam intensity A(A), and ensure that the irradiated area S(m 2 ) is slightly larger than the beam spot size, then under the reaction cross section σ, the number of uranium fission particles per unit time is:

[0148]

[0149] After that, uranium fission occurs, and a certain proportion of K1 is converted into delayed neutron precursor nuclei, which then undergo a half-life. A certain proportion of K2 will decay, and will undergo β-n decay, producing delayed neutrons.

[0150] When the precursor nuclei reach saturation, the accelerator beam is controlled to stop irradiating the reaction target.

[0151] In some embodiments, before controlling the beam of the accelerator 3 to irradiate the reaction target, the first driving assembly drives the detection member to move away from the first accommodating cavity along the height direction of the monitor calibration device.

[0152] Before controlling the beam of the accelerator 3 to irradiate the reaction target, the first driving assembly 21 drives the detection member 22 to move away from the first accommodating cavity 11 in the height direction. This is for the purpose of protecting the detection member 22 and ensuring the accuracy of the experiment and the stability of the equipment. Because the beam irradiating the reaction target will instantly trigger a violent nuclear reaction, produce a large amount of neutrons, gamma rays, and a high temperature and high pressure environment, if the detection member 22 is at a close distance, it is very easy to be damaged by strong radiation shock, high temperature roasting, particle sputtering, etc.; these risks can be avoided by moving away, and when the reaction is stable and the radiation environment is suitable, it can be detected close to obtain accurate data.

[0153] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application are included in the protection scope of the present application.

Claims

1. A delayed neutron monitor calibration device, characterized in that: include: A delayed neutron calibration source, comprising a shielding portion, a containing device, a detector and an accelerator; a first containing cavity and a first channel connected to the first containing cavity are formed inside the shielding portion, the first containing cavity is used to contain a reaction target, and the shielding portion can shield radiation; the containing device is arranged in the first containing cavity, and is used to contain the reaction target; at least part of the detector is arranged in the first containing cavity, and the detector is used to detect the neutron count rate in the first containing cavity; the beam emitted by the accelerator can pass through the first channel to irradiate the reaction target; A monitor assembly, wherein the monitor assembly is disposed on the shielding portion, and at least a portion of the monitor assembly extends into the first accommodating cavity, and is used to detect a neutron count rate in the first accommodating cavity; a first beam intensity detection device, the first beam intensity detection device comprising a penetrating ionization chamber, the penetrating ionization chamber being arranged between the delayed neutron calibration source and the accelerator along the emission direction of the beam, the penetrating ionization chamber being arranged close to the emission port of the accelerator so that the beam passes through the penetrating ionization chamber; A second beam intensity detection device, the second beam intensity detection device comprises a finger-type ionization chamber, the finger-type ionization chamber is arranged between the delayed neutron calibration source and the accelerator along the emission direction of the beam, the finger-type ionization chamber is arranged close to the first channel, and the finger-type ionization chamber can move along a first direction, wherein the first direction, the emission direction of the beam, and the height direction of the delayed neutron monitor calibration device intersect.

2. The delayed neutron monitor calibration device according to claim 1, characterized in that: The shielding portion has a second channel extending along the height direction of the monitor calibration device, the second channel is connected to the first accommodating cavity, the monitor assembly includes a first driving assembly and a detection member, the detection member passes through the second channel and extends into the first accommodating cavity, and the first driving assembly is used to drive the detection member to extend into or away from the first accommodating cavity along the height direction of the monitor calibration device.

3. The delayed neutron monitor calibration device according to claim 1, characterized in that: The first beam intensity detection device includes a mounting piece and a telescopic arm, one end of the telescopic arm is connected to the mounting piece, and the other end is connected to the penetration type ionization chamber, the mounting piece has an avoidance hole arranged opposite to the emission port of the accelerator, and the telescopic arm can drive the penetration type ionization chamber to approach or move away from the avoidance hole.

4. The delayed neutron monitor calibration device according to claim 3, characterized in that: The telescopic arm includes a first rotating member and a second rotating member, wherein a first end of the first rotating member is rotatably connected to the mounting member, a second end of the first rotating member is rotatably connected to a first end of the second rotating member, and the second rotating member is rotatably connected to the penetration type ionization chamber.

5. The delayed neutron monitor calibration device according to claim 1, characterized in that: The second beam intensity detection device includes a second driving component, and the second driving component can at least drive the finger-type ionization chamber to move along the first direction.

6. The delayed neutron monitor calibration device according to claim 5, characterized in that: The finger-type ionization chamber moves a distance of not less than 300 mm along the first direction.

7. The delayed neutron monitor calibration device according to claim 1, characterized in that: The delayed neutron calibration source comprises a third driving component, the shielding part is arranged on the third driving component, and the third driving component can at least drive the shielding part to move along the height direction of the monitor calibration device, the emission direction of the beam and the first direction.

8. A delayed neutron monitor calibration method, applied to the delayed neutron monitor calibration device according to any one of claims 1 to 7, characterized in that: The detection element includes a calibration detector and a detector to be tested. The delayed neutron monitor calibration method comprises: Adjusting the delayed neutron calibration source to a position of maximum beam intensity; Controlling the operation of the delayed neutron calibration source; Controlling the calibration detector to detect delayed neutrons to obtain a first counting rate; Controlling the detector to be tested to detect delayed neutrons to obtain a second counting rate; The detector under test is calibrated.

9. The delayed neutron monitor calibration method according to claim 8, characterized in that: The step of adjusting the delayed neutron calibration source to a position of maximum beam intensity comprises: Controlling the accelerator to emit a beam; controlling the first beam intensity detection device to measure the intensity of the beam; Controlling the second beam intensity detection device to measure the maximum beam intensity position of the beam; The delayed neutron calibration source is adjusted to move to the maximum beam intensity position.

10. The delayed neutron monitor calibration method according to claim 8, characterized in that: The calibrating the detector to be tested comprises: calculating an emissivity of the delayed neutron calibration source according to the first counting rate; The response value of the detector to be tested is calculated according to the second counting rate and the emission rate.

11. The delayed neutron monitor calibration method according to claim 8, characterized in that: The work of controlling the delayed neutron calibration source includes: Filling the reaction target in the containing device; Setting the beam intensity of the accelerator to a first beam intensity; The beam of the accelerator is controlled to irradiate the reaction target.

12. The delayed neutron monitor calibration method according to claim 11, characterized in that: The step of controlling the beam of the accelerator to irradiate the reaction target comprises: Controlling the beam of the accelerator to irradiate the reaction target to generate precursor nuclei; When the precursor nucleus reaches a saturation state, controlling the beam of the accelerator to stop irradiating the reaction target; The delayed neutron calibration source is left to stand until the prompt neutrons in the containing device disappear.

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