A delayed neutron monitor calibration device and calibration method

Abstract

The embodiment of the application provides a kind of delayed neutron monitor calibration device and calibration method, delayed neutron monitor calibration device.First beam intensity detection device includes penetrating ionization chamber, penetrating ionization chamber is set between delayed neutron calibration source and accelerator along the emission direction of beam, and penetrating ionization chamber is close to the emission port of accelerator, so that beam passes through penetrating ionization chamber;Second beam intensity detection device includes finger ionization chamber, finger ionization chamber is set between delayed neutron calibration source and accelerator along the emission direction of beam, and finger ionization chamber is close to the first channel, and finger ionization chamber can be moved along the first direction.The delayed neutron monitor calibration device provided in the embodiment of the application can realize accurate calibration of delayed neutron calibration source in beam field, improve the stability and efficiency of beam irradiation, and then improve the calibration accuracy of delayed neutron monitor.

Description

Technical Field

[0001] This application relates to delayed neutron monitoring technology, and in particular to a calibration device and calibration method for a delayed neutron monitor. Background Technology

[0002] During nuclear reactor operation, the primary accident risk stems from the leakage of radioactive materials due to structural damage. Monitoring delayed neutrons in the reactor loop water is one of the effective current methods for detecting potential damage to fuel elements. While related technologies use delayed neutron calibration sources to simulate radiation conditions, a calibration device for delayed neutron monitors is lacking for calibrating such monitors. Summary of the Invention

[0003] In view of this, embodiments of this application provide a calibration device and method for a delayed neutron monitor, which can calibrate the delayed neutron monitor in a beam field.

[0004] To achieve the above objectives, a first aspect of this application provides a delayed neutron monitor calibration device, comprising:

[0005] A delayed neutron calibration source includes a shielding section, a containment device, and an accelerator. The shielding section has a first containment cavity and a first channel communicating with the first containment cavity. The first containment cavity is used to contain a reaction target, and the shielding section is capable of shielding radiation. The containment device is disposed in the first containment cavity and is used to contain the reaction target. At least a portion of the detector is disposed in the first containment cavity, and the detector is used to detect the neutron count rate within the first containment cavity. The beam emitted by the accelerator can pass through the first channel and irradiate the reaction target.

[0006] A monitoring device assembly is disposed in the shielding portion, and at least a portion of the monitoring device assembly extends into the first receiving cavity for detecting the neutron count rate within the first receiving cavity.

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

[0008] The second beam intensity detection device includes a finger-shaped ionization chamber, which is disposed between the delayed neutron calibration source and the accelerator along the beam emission direction. The finger-shaped ionization chamber is located close to the first channel and is movable along a first direction, wherein the first direction, the beam emission direction, and the height direction of the delayed neutron monitoring calibration device intersect.

[0009] In one embodiment, the shielding portion has a second channel extending along the height direction of the monitoring calibration device, the second channel communicating with the first receiving cavity, the monitoring assembly including a first driving assembly and a probe, the probe extending through the second channel into the first receiving cavity, and the first driving assembly for driving the probe to extend into or away from the first receiving cavity along the height direction of the monitoring calibration device.

[0010] In one embodiment, the first beam intensity detection device includes a mounting component and a telescopic arm. One end of the telescopic arm is connected to the mounting component, and the other end is connected to the penetrating ionization chamber. The mounting component has a clearance hole disposed opposite to the emission port of the accelerator. The telescopic arm can drive the penetrating ionization chamber to move closer to or away from the clearance hole.

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

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

[0013] In one embodiment, the finger-shaped 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, and the shielding part is disposed on the third driving component. The third driving component is at least capable of driving the shielding part to move along the height direction of the monitoring calibration device, the emission direction of the beam, and the first direction.

[0015] A second aspect of this application provides a method for calibrating a delayed neutron monitor, applicable to the delayed neutron monitor calibration apparatus described in any embodiment of this application, wherein the detector includes a calibration detector and a detector under test.

[0016] The calibration method for the delayed neutron monitor includes:

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

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

[0019] The calibration detector is controlled to detect delayed neutrons to obtain a first count rate;

[0020] The detector under test is controlled to detect delayed neutrons to obtain a second count rate;

[0021] Calibrate the detector under test.

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

[0023] Control the accelerator to emit a beam;

[0024] The first beam intensity detection device is controlled to measure the intensity of the beam;

[0025] The second beam intensity detection device is controlled to measure the location of the maximum beam intensity.

[0026] Adjust the position of the delayed neutron calibration source to the position of maximum beam intensity.

[0027] In one embodiment, calibrating the detector under test includes:

[0028] The emission rate of the delayed neutron calibration source is calculated based on the first count rate;

[0029] The response value of the detector under test is calculated based on the second count rate and the emission rate.

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

[0031] The reaction target is filled into the containing device;

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

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

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

[0035] The beam from the accelerator is controlled to irradiate the reaction target, generating precursor nuclei;

[0036] When the precursor nucleus reaches saturation, the beam from the accelerator is controlled to stop irradiating the reaction target.

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

[0038] The delayed neutron monitor calibration device provided in this application embodiment uses a delayed neutron calibration source as its core to generate delayed neutrons. The monitor component detects the neutron count rate and acquires key calibration data. A first beam intensity detection device and a second beam intensity detection device are located at different positions. The first beam intensity detection device is close to the accelerator transmitter to capture the source beam information, while the second beam intensity detection device can move flexibly to detect the location of the maximum beam. In this way, accurate calibration of the delayed neutron calibration source in the beam field can be achieved, improving the stability and efficiency of beam irradiation, and thus improving the calibration accuracy of the delayed neutron monitor. Attached Figure Description

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

[0040] Figure 2 This is a schematic diagram of the delayed neutron monitor calibration device from another perspective in the embodiments of this application;

[0041] Figure 3 for Figure 1 A schematic diagram of the delayed neutron calibration source and monitoring instrument components in the diagram;

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

[0043] Figure 5 for Figure 1 A schematic diagram of the structure of the second beam intensity detection device in the diagram;

[0044] Figure 6 This is a flowchart of the delayed neutron monitor calibration method in the embodiments of this application.

[0045] Explanation of reference numerals in the attached figures

[0046] 100. Calibration device for delayed neutron monitor; 10. Calibration source for delayed neutron; 1. Shielding part; 11. First receiving cavity; 12. First channel; 13. Second channel; 2. Receiving device; 3. Accelerator; 20. Monitor assembly; 21. First drive assembly; 22. Detector; 30. First beam intensity detection device; 31. Penetrating ionization chamber; 32. Mounting component; 321. Clearance hole; 33. Telescopic arm; 331. First rotating component; 332. Second rotating component; 40. Second beam intensity detection device; 41. Finger-shaped ionization chamber; 42. Second drive assembly. Detailed Implementation

[0047] It should be noted that, unless otherwise specified, the embodiments and technical features in the embodiments of this application can be combined with each other, and the detailed descriptions in the specific implementation should be understood as explanations of the purpose of this application and should not be regarded as undue limitations on this application.

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

[0049] This application provides a delayed neutron monitor calibration device 100. Please refer to [link to relevant documentation]. 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 part 1, a receiving device 2, and a detector. The shielding part 1 has a first receiving cavity 11 and a first channel 12 communicating with it. The first receiving cavity 11 is used to receive a reaction target, and the shielding part 1 can shield radiation. The receiving device 2 is disposed in the first receiving cavity 11 and is used to receive the reaction target. At least a portion of the detector is disposed in the first receiving cavity 11, and the detector is used to detect the neutron count rate within the first receiving 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 disposed in the shielding part 1, and at least a portion of the monitor assembly 20 extends into the first receiving cavity 11 to detect the neutron count rate within the first receiving cavity 11. The first beam intensity detection device 30 includes a penetrating ionization chamber 31, which is disposed between the delayed neutron calibration source 10 and the accelerator 3 along the beam emission direction. The penetrating ionization chamber 31 is positioned close to the emission port of the accelerator 3 so that the beam passes through it. The second beam intensity detection device 40 includes a finger-shaped ionization chamber 41, which is disposed between the delayed neutron calibration source 10 and the accelerator 3 along the beam emission direction. The finger-shaped ionization chamber 41 is positioned close to the first channel 12 and is movable along a first direction, wherein the first direction, the beam emission direction, and the height direction of the delayed neutron monitor calibration device 100 intersect.

[0050] The Delayed Neutron Calibration Source 10 is a device specifically designed for calibrating and testing neutron-related measurement equipment. Delayed neutrons are neutrons emitted during the decay of certain radioactive nuclides in nuclear fission products. Unlike instantaneous neutrons, which are produced at the moment of fission, delayed neutrons are emitted after a certain time delay. The Delayed Neutron Calibration Source 10 accurately provides these neutrons to calibrate the accuracy of detection equipment when measuring delayed neutrons.

[0051] The delayed neutron calibration source 10 includes a shield 1, a containment device 2, a detector, and an accelerator 3.

[0052] The specific material of shielding part 1 is not limited here, but its material has a strong ability to absorb and scatter radiation. Its function is to block internal radiation from leaking outward, preventing harm to the surrounding environment and operators. At the same time, it isolates external interference radiation from entering the interior, ensuring that the calibration source is not disturbed and maintaining a stable radiation environment.

[0053] For example, the shielding part 1 is made of a hydrogen-containing material. For instance, 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 its center to form a first receiving cavity 11.

[0054] The containment device 2 is typically a high-temperature and radiation-resistant container, made of special ceramics or metal alloys. It provides a stable and sealed storage space for the reaction target, ensuring that the target is in the predetermined position so that the accelerator 3 beam can accurately act on the target. It can also contain the reaction products and prevent them from leaking and contaminating the equipment.

[0055] For example, the containing device 2 is a cylindrical cup-shaped structure made of titanium alloy with a 2mm annular bottom surface, a wall thickness of 2mm, an inner diameter of 50mm, an outer diameter of 70mm, and a height of 50mm. Using titanium alloy can reduce the corrosion of the container by the solution and reduce the obstruction effect on the influx of proton beams and the emission of slowed neutrons.

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

[0057] An accelerator is a device that uses electric and magnetic fields to accelerate charged particles (such as protons and electrons) to a high-energy state. The accelerated particle beam has sufficient energy to collide with a reaction target and trigger a nuclear reaction, providing an energy source for the production of delayed neutrons. Common types include linear accelerators and cyclotron accelerators.

[0058] In some embodiments, the accelerator 3 includes a beam deflection magnet that drives the beam to irradiate or deflect from the reactive target.

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

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

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

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

[0063] The reaction target is a key component that enables nuclear reactions to occur under the irradiation of the particle beam generated by accelerator 3. The specific composition of the reaction target is not limited here, but is determined based on the nuclear reaction raw materials used in the actual calibration.

[0064] For example, the reaction target can be a radioactive nuclide such as uranium or plutonium that can undergo a fission reaction. When these nuclides are bombarded by high-energy particles (such as protons and neutrons) generated by accelerator 3, they will undergo a fission reaction 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 easily measured. Taking a uranium-containing solution as an example, the uranium concentration should not be less than 0.01 g / ml, so that a concentration of not less than 10 can be obtained. 4 Slow neutron emission rate on the order of / s.

[0066] For example, the reaction target can be a radioactive nuclide such as uranium or plutonium that can undergo a fission reaction. When these nuclides are bombarded by high-energy particles (such as protons and neutrons) generated by accelerator 3, they will undergo a fission reaction and produce a variety of products, including delayed neutrons.

[0067] A detector is an instrument that interacts with neutrons and converts information such as neutron flux into electrical or counting signals. Common types include scintillation detectors and gas detectors. Scintillation detectors utilize the interaction between neutrons and a scintillator to emit light, which is then converted into an electrical signal by a photoelectric conversion element. Gas detectors record signals by ionizing gas with neutrons to produce ion pairs, and are used to accurately monitor the quantity and energy of neutrons within a containment cavity.

[0068] The monitoring instrument assembly 20 consists of multiple detectors and supporting structures. Some detectors are inserted into the first receiving cavity 11 and are responsible for detecting information such as neutron flux and count rate in the cavity. They convert neutron radiation signals into electrical signals and count signals, 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 works by using radiation to ionize gas. 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, through which the beam passes directly. It monitors parameters such as the intensity and stability of the beam emitted from the accelerator 3 in real time, and provides feedback for adjustment to ensure beam quality.

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

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

[0072] The finger-shaped ionization chamber 41 resembles a finger in shape, with a compact and small structure that allows for flexible movement. During operation, the beam ionizes the internal gas, and with its high sensitivity, it detects minute changes in the beam. By moving along the first direction, it 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 ease of explanation, the first direction in this embodiment is the direction shown in the accompanying drawings.

[0074] The delayed neutron monitor calibration device 100 provided in this application embodiment has a delayed neutron calibration source 10 as its core, which generates delayed neutrons. The monitor component 20 detects the neutron count rate and obtains 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 accelerator 3 emitter to capture the source beam information, while the second beam intensity detection device 40 can move flexibly to detect the position of the maximum beam. In this way, accurate calibration of the delayed neutron calibration source 10 in the beam field can be achieved, improving the stability and efficiency of beam irradiation, and thus improving the calibration accuracy of the delayed neutron monitor.

[0075] In some embodiments, please refer to Figures 1 to 3The shielding part 1 has a second channel 13 extending along the height direction of the monitoring instrument calibration device. The second channel 13 is connected to the first receiving cavity 11. The monitoring instrument assembly 20 includes a first driving assembly 21 and a probe 22. The probe 22 extends into the first receiving cavity 11 through the second channel 13. The first driving assembly 21 is used to drive the probe 22 to extend into or away from the first receiving cavity 11 along the height direction of the monitoring instrument calibration device.

[0076] The second channel 13 is a specially designed tubular passage on the shielding section 1. Its direction is along the height of the monitoring instrument calibration device, and the material is mostly metal or alloy with good radiation shielding performance, such as lead alloy or stainless steel. Its key function is to provide a channel for the detector 22 in the monitoring instrument assembly 20 to enter and exit the first receiving cavity 11, so as to ensure that the internal radiation leakage is minimized while allowing the detector 22 to be smoothly positioned to perform the detection task.

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

[0078] For example, the first drive assembly 21 consists of a motor, a lead screw, a guide rail, and a matching controller. The motor serves as the power source, and through a transmission structure such as a lead screw and nut pair or a gear and rack, combined with the guidance of the guide rail, it precisely drives the detector 22 to move along a set height direction; the controller is responsible for receiving external commands, adjusting the motor's operating state, and achieving flexible position control of the detector 22.

[0079] The detector 22 is the core component in the monitoring instrument assembly 20 that actually interacts with neutrons and collects signals. Common types include scintillation detectors and gas detectors. Scintillation detectors use neutrons to bombard a scintillator to make it emit light, and then the light signal is converted into an electrical signal by a photoelectric conversion element. Gas detectors rely on neutrons to ionize the gas, generate ion pairs, and collect them to form an electrical signal, thereby detecting information such as the flux and energy of neutrons in the first containment cavity 11.

[0080] The shielding part 1 is equipped with a second channel 13 along the height direction, which fits the structure of the monitoring instrument component 20. The detector 22 can enter and exit the first receiving cavity 11 as needed through the second channel 13, while the first driving component 21 gives the detector 22 the ability to dynamically adjust its position. The staff can operate it remotely or locally, so that the detector 22 can detect neutrons at different height positions, meet the diverse experimental and calibration needs, fully capture the neutron distribution characteristics in the first receiving cavity 11, and at the same time help reduce the risk of radiation to the staff.

[0081] In some embodiments, please refer to Figures 1 to 2 , Figure 4The first beam intensity detection device 30 includes a mounting component 32 and a telescopic arm 33. One end of the telescopic arm 33 is connected to the mounting component 32, and the other end is connected to the penetrating ionization chamber 31. The mounting component 32 has a clearance hole 321 that is disposed opposite to the emission port of the accelerator 3. The telescopic arm 33 can drive the penetrating ionization chamber 31 to move closer to or away from the clearance hole 321.

[0082] Mounting component 32 is the basic support and positioning component of the first beam intensity detection device 30. It is usually made of metal (such as aluminum alloy or stainless steel) and has sufficient structural strength and stability. Mounting component 32 provides a stable connection point for telescopic arm 33, ensuring that the entire beam monitoring structure is reliably fixed. The clearance hole 321 is a specially made hole on mounting component 32, which precisely corresponds to the accelerator 3 emission port. Its shape and size are designed according to the beam outlet specifications of accelerator 3, with the purpose of allowing the beam to pass through unobstructed and preventing mounting component 32 from blocking the beam transmission path.

[0083] In some embodiments, a radiation-resistant and high-temperature-resistant ceramic protective ring, such as an alumina ceramic, is added around the edge of the clearance hole 321. This ring prevents beam scattering and absorbs trace amounts of leaked radiation, protecting the mounting component 32 from radiation damage. The surface of the protective ring is polished to reduce the probability of beam reflection and improve beam transmission efficiency.

[0084] The bottom of the mounting component 32 is designed with adjustable height and angle support feet. The support feet use shock-absorbing rubber pads and screw lifting structure to facilitate fine-tuning of the posture of the mounting component 32 during the equipment installation and commissioning stage, ensuring that the clearance hole 321 is precisely aligned with the launch port of the accelerator 3; and reducing vibration transmission during operation to maintain the stability of the monitoring device.

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

[0086] Mounting component 32 provides a stable foundation, while clearance hole 321 ensures smooth beam emission. Telescopic arm 33 flexibly moves the penetrating ionization chamber 31 closer to or further away from the accelerator 3 emission port as needed. Before the experiment begins, the telescopic arm 33 can be manipulated to bring the ionization chamber close to the emission port for precise monitoring of the initial beam; during the experiment, its position can be dynamically adjusted as needed to comprehensively control the beam state under different operating conditions; this aims to provide stable and accurate beam data for delayed neutron calibration, ensuring the reliability of the entire calibration process.

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

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

[0089] The first rotating component 331 serves as a connecting hub, with its first end rotatably connected to the mounting component 32. It can rotate flexibly around a specific axis to achieve angle adjustment. The second end is also rotatably connected to the second rotating component 332, giving the entire telescopic arm 33 a versatile shape adjustment capability, which is beneficial for accurately positioning the penetrating ionization chamber 31.

[0090] The second rotating component 332 bears the important responsibility of connecting the first rotating component 331 and the penetrating ionization chamber 31. Its first end is rotatably connected to the first rotating component 331, forming a flexible joint that can change the relative angle as needed; its second end is stably rotatably connected to the penetrating ionization chamber 31, which can accurately transmit the motion from the first rotating component 331 and work with the first rotating component 331 to control the ionization chamber to move flexibly and orient itself at multiple angles in three-dimensional space, meeting different beam monitoring needs.

[0091] Rotary connections refer to a connection method in which two components 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 components to rotate relative to each other, giving the structure flexibility. In this device, with the help of multiple rotary connections, the telescopic arm 33 breaks away from 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-rotation structure design, using a combination of a first rotating component 331 and a second rotating component 332 connected in series, both of which are rotatably connected, to construct a flexible architecture similar to a robotic arm. During installation, the initial angles of each rotating component can be easily adjusted to fit the spatial layout of the equipment; during operation, as experimental and monitoring needs change, the first and second rotating components 332 cooperate with each other to drive the penetrating ionization chamber 31 to swing and extend in all directions, accurately approaching or moving away from the accelerator 3 emission port, capturing beam information in real time without blind spots, ensuring stable and reliable beam, and providing a solid data foundation for delayed neutron calibration.

[0093] In some embodiments, please refer to Figures 1 to 2 , Figure 5The second beam intensity detection device 40 includes a second drive component 42, which is capable of driving the finger-shaped ionization chamber 41 to move along a first direction.

[0094] The second drive component 42 is the key power and control unit of the second beam intensity detection device 40. The specific type of the second drive component 42 is not limited here.

[0095] For example, the second drive assembly 42 includes a motor, a transmission mechanism, a guide rail, and a controller. The motor serves as a power source, providing driving force; the transmission mechanism is responsible for converting the rotational motion of the motor into linear motion, precisely pushing the finger-shaped ionization chamber 41 to move; the guide rail is used to guide the direction of movement of the ionization chamber, ensuring linearity and stability; the controller receives external commands and regulates the motor's operating state, thereby precisely controlling the movement process of the finger-shaped ionization chamber 41.

[0096] In the delayed neutron calibration process, the beam characteristics vary with operating conditions. With the aid of the second drive assembly 42, the finger-shaped ionization chamber 41 is no longer limited to fixed-point monitoring. The second drive assembly 42 drives the finger-shaped ionization chamber 41 to move dynamically along the first direction, allowing it to move between different positions as needed and detect the location with the highest beam intensity. This provides a positional 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, avoiding the risk of radiation exposure. The specific operating procedure is as follows:

[0097] The finger-shaped ionization chamber 41 is placed within the experimental area, positioned at the front end of the entrance port. The second drive assembly 42 drives the finger-shaped 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 position with the maximum beam current, the second drive assembly 42 drives the finger-shaped ionization chamber 41 away from the position with the maximum beam current.

[0098] In some embodiments, the second drive component 42 can also drive the finger-shaped ionization chamber 41 to move along the height direction.

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

[0100] The lower limit of the movement stroke of the finger-shaped ionization chamber 41 along the first direction is not less than 300mm, which means that it has a sufficiently long range of motion in the given direction and can travel at least 300mm. This ensures that the ionization chamber can cover a large area of ​​the key areas of the equipment, avoid missing important monitoring points due to limited movement range, and fully capture all kinds of changes in the beam transmission process.

[0101] In some embodiments, please refer to Figures 1 to 5The delayed neutron calibration source 10 includes a third driving component, and a shield 1 is disposed on the third driving component. The third driving component is at least capable of driving the shield 1 to move along the height direction of the monitoring calibration device, the beam emission direction and the first direction.

[0102] The third drive component serves as a key power and displacement control unit for the delayed neutron calibration source 10. The specific type of the third drive component is not specified here.

[0103] For example, the third drive component integrates a motor, a transmission mechanism, a guide device, and an intelligent control system. The motor provides the initial power, the transmission mechanism is responsible for accurately converting the rotational motion of the motor into linear motion or displacement drive in a specific direction, and the guide device ensures that the movement trajectory of the shield 1 is accurate and stable. The intelligent control system receives external commands, coordinates the operation of the motor and transmission components, and accurately controls the movement process of the shield 1 in complex three-dimensional space.

[0104] The third driving component allows for free movement in three dimensions, which facilitates the adjustment of the shielding part 1's relative position within the beam field, adapting to different experimental procedures, finding the maximum beam intensity, and improving reaction efficiency. It also provides feasibility for personnel to conduct experimental measurements away from the experimental platform, avoiding the risk of radiation exposure.

[0105] This application provides a method for calibrating a delayed neutron monitor. Please refer to [link to relevant documentation]. Figures 1 to 6 The detector 22 includes a calibration detector and a detector under test. The calibration method for the delayed neutron monitor includes the following steps S101 to S105:

[0106] Step S101: Adjust the delayed neutron calibration source to the position of maximum beam intensity.

[0107] Adjust the delayed neutron calibration source 10 to this position. This is to ensure that the calibration source receives the strongest beam, so as to ensure that the reaction target is efficiently excited and maximize the delayed neutron production efficiency. For example, with the help of the third drive component equipped with the delayed neutron calibration source 1010, precise fine-tuning can be performed along the height direction and the beam emission direction to achieve a perfect match between the calibration source and the strongest beam, thereby improving the nuclear reaction efficiency.

[0108] Step S102: Control the operation of the delayed neutron calibration source.

[0109] The delayed neutron calibration source 10 operates, providing delayed neutron detection conditions for the detector 22, and preparing for subsequent calibration.

[0110] Step S103: Control the calibration detector to detect delayed neutrons and obtain the first count rate.

[0111] A calibration detector is a detector whose response value is known. By placing the calibration detector in a delayed neutron radiation environment, the first count rate can be measured through the calibration detector, and the emissivity of delayed neutrons in the delayed neutron calibration source 10 can be obtained, which prepares for the calibration of the detector under test.

[0112] Step S104: Control the detector under test to detect delayed neutrons and obtain the second count rate.

[0113] A detector under test (DUT) refers to a detector whose response value is currently unknown and requires measurement using a delayed neutron monitor calibration method. Since direct measurement of the response value is very difficult, the response value of the DUT can be measured by combining the second count rate obtained from the DUT measurement with the emissivity calculated from the calibration detector.

[0114] Step S105: Calibrate the detector under test.

[0115] The response value of the detector under test can be calculated based on the first count rate measured by the calibrated detector and the second count rate of the detector under test.

[0116] The delayed neutron monitor calibration device 100 provided in this application embodiment has a delayed neutron calibration source 10 as its core, which generates delayed neutrons. The monitor component 20 detects the neutron count rate and obtains key calibration data. The first beam intensity detection device 30 and the second beam intensity detection device 40 are located in different positions. The first beam intensity detection device 30 is close to the accelerator 3 emitter to capture the source beam information, while the second beam intensity detection device 40 is close to the first channel 12 to control the beam before it enters the calibration source. It can move flexibly and monitor the beam in all directions and dynamically. In this way, the delayed neutron calibration source 10 can be accurately calibrated in the beam field, improving the stability and efficiency of beam irradiation, and thus improving the calibration accuracy of the delayed neutron monitor.

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

[0118] Control the accelerator to emit beams.

[0119] As the key device for generating high-energy particle beams, accelerator 3's beam emission control is the starting point of the entire calibration process. The beam characteristics (such as intensity, energy, and particle type) directly affect subsequent nuclear reaction processes and the production of delayed neutrons. Precisely setting accelerator 3 parameters ensures stable beam emission, laying the foundation for subsequent measurements and calibration. For example, adjusting parameters such as the accelerating voltage and focusing magnetic field of accelerator 3 allows the beam to reach the expected energy and intensity levels, meeting the basic requirements of the experiment.

[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 accelerator 3 and the degree of subsequent nuclear reaction excitation. Stable and accurate beam intensity is essential to ensure reaction repeatability and data reliability. This device uses components such as the penetrating ionization chamber 31 to collect the ion pairs generated by the ionized gas as the beam passes through, converting them into electrical signals to accurately quantify the beam intensity. If the intensity deviates from the preset value, it can provide timely feedback and adjustment to maintain stable experimental conditions.

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

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

[0124] In some embodiments, the second driving component 42 can drive the finger-shaped ionization chamber 41 to move along a first direction, an emission direction, and a height direction. The finger-shaped ionization chamber 41 can move in space under the drive of the second driving component 42 to locate the position with the maximum beam intensity. After the finger-shaped ionization chamber 41 determines the position with the maximum beam intensity, the delayed neutron calibration source 10 moves entirely to that position, allowing the beam to enter from the first channel 12 and irradiate the reaction target. Once the position of the delayed neutron calibration source 10 is fixed, the second driving component 42 drives the finger-shaped ionization chamber 41 away from the first channel 12.

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

[0126] The steps for locating the location of maximum beam intensity in the finger-type ionization chamber 41 are as follows:

[0127] First, the second driving assembly 42 drives the finger-shaped ionization chamber 41 to move along the first direction to the front end of the first channel 12. After aligning with the first channel 12 in the first direction, the relative position of the finger-shaped ionization chamber 41 and the first channel 12 remains constant. Then, 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-shaped ionization chamber 41 finds the position with the maximum beam intensity and stops moving. Finally, the second driving assembly 42 drives the finger-shaped ionization chamber 41 to move along the first direction away from the first channel 12, thus allowing the beam of maximum intensity to enter the first channel 12.

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

[0129] Based on the location of the maximum beam intensity measured in the steps, the delayed neutron calibration source 10 is adjusted and moved to that position. This is to ensure that the calibration source receives the strongest beam, ensuring that the reaction target is efficiently excited and maximizing the delayed neutron production efficiency. For example, by using the third drive component equipped with the delayed neutron calibration source 10, precise fine-tuning can be performed along the height direction and the beam emission direction to achieve a perfect match between the calibration source and the strongest beam, thereby improving the nuclear reaction efficiency.

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

[0131] The 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 emissivity. The response can be considered a constant value; different detectors have different responses. Here, the delayed neutron monitor calibration method involves measuring the response value of an unknown detector (i.e., the detector under test in this paper). The response of the calibration detector is known. By placing the calibration detector in the delayed neutron calibration source 10 of this application, the delayed neutron calibration source 10 provides a stable delayed neutron radiation condition, i.e., the emissivity remains constant. By measuring the first count rate obtained from the calibration detector and the known response of the calibration detector, the neutron emissivity of the delayed neutron calibration source 10 can be obtained.

[0133] The response value of the detector under test is calculated based on the second count rate and the emission rate.

[0134] The detector under test is placed in the delayed neutron calibration source 10. Under the same neutron emissivity, the second count rate of the detector under test is measured. Based on the mathematical relationship between the response value and the ratio of the count rate to the emissivity, the response value of the detector under test can be obtained, thus completing the calibration work. Compared with other calibration methods, this method helps to reduce the calibration difficulty.

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

[0136] The reaction target is filled into the containment device.

[0137] The reaction target, as the key material basis for the nuclear reaction, is filled in the containment device 2. The containment device 2 provides a stable environment for the target, ensuring that the beam from the subsequent accelerator 3 accurately acts on the target, while also containing the reaction products to prevent leakage and contamination of the equipment and the surrounding environment.

[0138] Set the accelerator's beam intensity to the first beam intensity.

[0139] Based on experimental or calibration requirements, the beam intensity of accelerator 3 is precisely set as the first beam intensity. Beam intensity is a key parameter affecting the intensity of nuclear reactions and the amount of delayed neutrons produced. Different beam intensities will induce nuclear reactions of different scales. Setting an appropriate first beam intensity is a prerequisite for obtaining accurate calibration data.

[0140] The beam from the accelerator is controlled to irradiate the reaction target.

[0141] Accelerator 3 is manipulated to stably and accurately irradiate the reaction target with a beam of predetermined intensity. This step is the core operation that triggers the nuclear reaction and promotes the generation of delayed neutrons. The beam interacts with the target, and the atomic nuclei absorb energy to undergo fission, excitation, and other processes, thereby giving birth to delayed neutrons.

[0142] It should be noted that when calibrating the detector and measuring the detector under test, the working environment of the delayed neutron calibration source must remain unchanged to ensure that the emission rate of delayed neutrons is consistent when calibrating the detector and measuring the detector under test.

[0143] In some embodiments, controlling the beam irradiation reaction target of the accelerator includes:

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

[0145] Precursor nuclei are a key intermediate product in nuclear reactions. When the beam from accelerator 3 precisely irradiates the reaction target at a set intensity, the target's atomic nuclei absorb the energy carried by the beam particles, undergoing nuclear reactions such as fission and excitation, thereby generating a series of nuclides in an unstable state—these are the precursor 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, producing numerous fission fragments such as Br-87 and I-137. Some of these fragments further decay into precursor nuclei, which have the potential to subsequently produce delayed neutrons.

[0146] The slow-emitting neutron precursor nucleus undergoes spontaneous decay and fission, producing a certain number of slow-emitting neutrons, which is the emission rate.

[0147] It should be noted that the emission rate of delayed neutrons is related to many factors. Here, we take uranium as an example, assuming the uranium concentration is c (kg·m³). -3 The volume of the reaction solution that participates in the reaction is V(m). 3 The proton beam current intensity is A(A), and the irradiated area is guaranteed to be S(m²). 2 If the size is slightly larger than the beam size, then under the reaction cross section σ, the number of uranium fission particles per unit time is:

[0148]

[0149] Afterward, uranium undergoes fission, and a certain proportion of it is converted into slow-emitting neutron precursor nuclei (K1). These precursor nuclei then pass through a half-life. During decay, a certain proportion of K2 undergoes β-n decay, producing slow-emitting neutrons.

[0150] When the precursor nuclei reach saturation, the beam from the control accelerator stops irradiating the reaction target.

[0151] In some embodiments, before the beam of the accelerator 3 irradiates the reaction target, the first drive assembly drives the probe away from the first receiving cavity along the height direction of the monitor calibration device.

[0152] Before the beam from the accelerator 3 irradiates the reaction target, the first drive assembly 21 drives the detector 22 away from the first receiving cavity 11 along the height direction. This is for the purpose of protecting the detector 22 and ensuring the accuracy of the experiment and the stability of the equipment. Because the beam irradiation of the reaction target will instantly trigger a violent nuclear reaction, producing a large number of neutrons, gamma rays, and a high-temperature and high-pressure environment, if the detector 22 is at close range, it is very easy to be damaged by strong radiation impact, high temperature baking, particle sputtering, etc. Moving away can avoid these risks, and it can be brought closer for detection when the reaction is stable and the radiation environment is suitable to obtain accurate data.

[0153] The above description is merely a preferred embodiment of this application and is not intended to limit the application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this application are included within the scope of protection of this application.

Claims

1. A calibration device for a delayed neutron monitor, characterized in that, include: A delayed neutron calibration source includes a shield, a containment device, a detector, and an accelerator. The shield has a first containment cavity and a first channel communicating with it. The first containment cavity is used to contain a reaction target, and the shield is capable of shielding radiation. The containment device is disposed within the first containment cavity and is used to contain the reaction target. At least a portion of the detector is disposed within the first containment cavity, and the detector is used to detect the neutron count rate within the first containment cavity. The beam emitted by the accelerator can pass through the first channel and irradiate the reaction target. A monitoring device assembly is disposed in the shielding portion, and at least a portion of the monitoring device assembly extends into the first receiving cavity for detecting the neutron count rate within the first receiving cavity. A first beam intensity detection device, comprising a penetrating ionization chamber, wherein the penetrating ionization chamber is disposed between the delayed neutron calibration source and the accelerator along the emission direction of the beam, and the penetrating ionization chamber is disposed close to the emission port of the accelerator so that the beam passes through the penetrating ionization chamber; The second beam intensity detection device includes a finger-shaped ionization chamber, which is disposed between the delayed neutron calibration source and the accelerator along the beam emission direction. The finger-shaped ionization chamber is located close to the first channel and is movable along a first direction, wherein the first direction, the beam emission direction, and the height direction of the delayed neutron monitoring calibration device intersect.

2. The calibration device for a delayed neutron monitor according to claim 1, characterized in that, The shielding portion has a second channel extending along the height direction of the monitoring instrument calibration device. The second channel communicates with the first receiving cavity. The monitoring instrument assembly includes a first driving assembly and a probe. The probe extends into the first receiving cavity through the second channel. The first driving assembly is used to drive the probe to extend into or away from the first receiving cavity along the height direction of the monitoring instrument calibration device.

3. The calibration device for a delayed neutron monitor according to claim 1, characterized in that, The first beam intensity detection device includes a mounting component and a telescopic arm. One end of the telescopic arm is connected to the mounting component, and the other end is connected to the penetrating ionization chamber. The mounting component has a clearance hole that is disposed opposite to the emission port of the accelerator. The telescopic arm can drive the penetrating ionization chamber to move closer to or away from the clearance hole.

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

5. The calibration device for a delayed neutron monitor according to claim 1, characterized in that, The second beam intensity detection device includes a second driving component, which is at least capable of driving the finger-shaped ionization chamber to move along the first direction.

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

7. The calibration device for a delayed neutron monitor according to claim 1, characterized in that, The delayed neutron calibration source includes a third driving component, and the shielding part is disposed on the third driving component. The third driving component is at least capable of driving the shielding part to move along the height direction of the monitoring instrument calibration device, the beam emission direction, and the first direction.

8. A method for calibrating a delayed neutron monitor, applied to the delayed neutron monitor calibration apparatus according to any one of claims 1 to 7, characterized in that, The detector includes a calibration detector and a detector under test. The calibration method for the delayed neutron monitor includes: Adjust the delayed neutron calibration source to the position of maximum beam intensity; Control the operation of the delayed neutron calibration source; The calibration detector is controlled to detect delayed neutrons to obtain a first count rate; The detector under test is controlled to detect delayed neutrons to obtain a second count rate; Calibrate the detector under test.

9. The calibration method for a delayed neutron monitor according to claim 8, characterized in that, Adjusting the delayed neutron calibration source to the position of maximum beam intensity includes: Control the accelerator to emit a beam; The first beam intensity detection device is controlled to measure the intensity of the beam; The second beam intensity detection device is controlled to measure the location of the maximum beam intensity. Adjust the position of the delayed neutron calibration source to the position of maximum beam intensity.

10. The calibration method for a delayed neutron monitor according to claim 8, characterized in that, The calibration of the detector under test includes: The emission rate of the delayed neutron calibration source is calculated based on the first count rate; The response value of the detector under test is calculated based on the second count rate and the emission rate.

11. The calibration method for a delayed neutron monitor according to claim 8, characterized in that, The operation of controlling the delayed neutron calibration source includes: The reaction target is filled into the containing device; Set the beam intensity of the accelerator to a first beam intensity; The beam from the accelerator is controlled to irradiate the reaction target.

12. The calibration method for a delayed neutron monitor according to claim 11, characterized in that, The control of the beam from the accelerator to irradiate the reaction target includes: The beam from the accelerator is controlled to irradiate the reaction target, generating precursor nuclei; When the precursor nucleus reaches saturation, the beam from the accelerator is controlled to stop irradiating the reaction target. The delayed neutron calibration source is left to stand until the instantaneous neutrons in the containment device disappear.

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