A low-scattering mono-energetic neutron generation device and control method

Abstract

The application relates to a low-scattering monochromatic neutron generating device and a control method, which comprise a target, a target tube, a KF-CF flange adapter pipe, a bellows and an electric push rod group; the rear end of the target is connected with one end of the target tube, the other end of the target tube is connected with one end of the bellows through the flange adapter pipe, the other end of the bellows is connected with a beam line of an accelerator, and the electric push rod group is arranged outside the bellows and used for supporting and rotating the KF-CF flange adapter pipe, so as to drive the target tube and the target to rotate; the electric push rod group drives the bellows to bend, the target tube and the target to tilt through periodic extension and contraction, so that the target swings in two directions perpendicular to each other, the swinging in the two directions is combined into a rotating motion, and then the hitting point of the target makes a circular motion around the center of the target. The application has a simple structure, reduces the scattering interference of redundant components on the monochromatic neutrons, effectively guarantees the monochromaticity of the monochromatic neutrons, and prolongs the service life of the equipment.

Description

Technical Field

[0001] This invention relates to the field of monoenergetic neutron generation technology, and more particularly to a low-scattering monoenergetic neutron generation device and control method. Background Technology

[0002] Accelerator-based monoenergetic neutron sources produce monoenergetic neutrons by accelerating charged particles to bombard target materials, resulting in nuclear reactions. They are widely used in nuclear physics research, radiation protection, and other fields. Their core requirements include: first, maintaining a vacuum environment, where the target material must also serve as a vacuum seal to ensure the integrity of the vacuum between the beamline and the target area; second, reducing neutron scattering, where the target and related equipment must be as lightweight and compact as possible to maintain the monochromaticity of the monoenergetic neutrons; and third, achieving target rotation, which allows the charged particle impact point to circulate within the target plane, dispersing energy deposition, mitigating target damage caused by thermal effects, and simultaneously improving the uniformity of neutron production.

[0003] In existing technologies, such as the rotating target scheme disclosed in patent CN 114545487 B, a bellows connects the target and the beamline to maintain a vacuum. A deflection mechanism, consisting of horizontal and vertical motors, transmission mechanisms, and a ground support, drives the target to rotate eccentrically. However, this scheme has significant drawbacks: the deflection mechanism includes multi-directional motors, complex transmission components, and a ground support, resulting in a large overall device mass and size, increasing the risk of neutron scattering and affecting the monochromaticity of monoenergetic neutrons. Furthermore, the complex structure leads to inconvenient operation and high maintenance costs, making it difficult to meet the stringent requirements of monoenergetic neutron sources for portability, low scattering, and stability. Therefore, a simplified structural scheme that can simultaneously meet the requirements of vacuum sealing, low scattering, and efficient rotation is urgently needed, thus requiring a low-scattering monoenergetic neutron generation device and control method. Summary of the Invention

[0004] The purpose of this invention is to provide a low-scattering monoenergetic neutron generating device and a control method.

[0005] To achieve the above objectives, the present invention is implemented according to the following technical solution:

[0006] The present invention includes a target, a target tube, a KF-CF flange adapter, a bellows, and an electric push rod assembly; the rear end of the target is connected to one end of the target tube, the other end of the target tube is connected to one end of the bellows via the flange adapter, the other end of the bellows is connected to the beamline of the accelerator, and the electric push rod assembly is disposed outside the bellows to support and rotate the KF-CF flange adapter, thereby driving the target tube and the target to rotate;

[0007] The electric push rod assembly periodically extends and retracts, causing the bellows to bend and the target tube and target to tilt, so that the target swings in two mutually perpendicular directions. The swings in the two directions combine to form a rotational motion, which in turn causes the target point to make a circular motion around the center of the target.

[0008] Furthermore, the target is a circular thin sheet composed of a target material and a metal substrate, which is welded and fixed to one end of the target tube. It is used to seal the vacuum, block charged particles, and react with the incident particles to produce neutrons.

[0009] Furthermore, the corrugated pipe is a flexible metal tube, and CF flanges are provided at both ends of the corrugated pipe.

[0010] Furthermore, the electric actuator assembly includes four electric actuators, which achieve linear reciprocating motion under electric drive.

[0011] Furthermore, the electric push rods are parallel to the bellows and are evenly distributed around the bellows at 90-degree intervals. Among the four electric push rods, the extension and retraction movements of the two electric push rods on the same axis are opposite in phase.

[0012] In another aspect, a control method for a low-scattering monoenergetic neutron device, used to execute the aforementioned low-scattering monoenergetic neutron generating device, specifically includes:

[0013] (1) Connect the rotating target assembly, consisting of the target, target tube, KF-CF flange adapter, bellows and four electric push rods, to the accelerator beamline to ensure the CF flange at both ends of the bellows is sealed and to maintain the ultra-high vacuum environment of the target area and the beamline.

[0014] (2) Based on the requirements for monoenergetic neutron production, the radius r and period T of the circular motion of the target point around the target center are set. Based on the radius r and period T, the extension and retraction motion parameters of the four electric push rods are calculated. The electric push rods on two mutually perpendicular axes correspond to the x and y directions of the circular motion, respectively. The extension and retraction phases of the two electric push rods on the same axis are opposite.

[0015] (3) Control the four electric push rods to periodically extend and retract according to the set extension and retraction motion parameters, so that the bellows bends and the target tube and target tilt. By combining the sinusoidal motion of the electric push rod in the x direction with the cosine motion of the electric push rod in the y direction, the target point is driven to make a uniform circular motion with a period T around the target center with a radius of r.

[0016] (4) Monitor the neutron scattering intensity of the device in real time. If the scattering intensity exceeds the preset threshold, adjust the extension and retraction range or period of the electric push rod to optimize the uniformity of the target trajectory, reduce the additional scattering caused by the unstable movement of the target and surrounding components, and maintain the monochromaticity of the monoenergetic neutron.

[0017] Furthermore, in step (2), the telescopic motion parameters of the electric push rod include the telescopic amplitude and frequency. The telescopic amplitude is proportional to the radius r of the circular motion of the target point, and the frequency corresponds to the reciprocal of the period T.

[0018] Furthermore, in step (3), the rotational motion of the electric motor is converted into linear extension and retraction motion through the transmission device of the electric push rod. The extension and retraction of the push rod are controlled by the forward and reverse rotation of the electric motor, so as to realize the oscillation synthesis of the target in the x and y directions.

[0019] Furthermore, the radius and period of the circular motion of the firing point around the target center are controlled by adjusting the range of motion and extension / retraction period of the electric push rod end.

[0020] The beneficial effects of this invention are:

[0021] This invention relates to a method for generating low-scattering monoenergetic neutrons. Compared with existing technologies, this invention has the following technical advantages:

[0022] 1. This invention employs four electric push rods arranged around the bellows to simultaneously support and drive the rotation of the target, replacing the complex horizontal and vertical motors, transmission mechanisms, and ground supports in the prior art. This significantly reduces the weight and volume of the equipment, simplifies the structure, reduces the scattering interference of neutrons by redundant components, and effectively ensures the monochromaticity of monoenergetic neutrons.

[0023] 2. This invention utilizes the periodic extension and retraction of an electric actuator to decompose the rotational motion into two mutually perpendicular sine / cosine linear motions. This precisely controls the target point to perform uniform circular motion around the target center, achieving uniform dispersion of energy deposition, extending the target's lifespan, and improving the uniformity of neutron production. The electric actuator assembly has a simple structure and reliable transmission. Furthermore, the target tube can be quickly replaced through the KF flange design, reducing the complexity and cost of equipment maintenance and improving the system's stability and ease of use. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of a low-scattering monoenergetic neutron generating device according to the present invention;

[0025] Figure 2 This is a schematic diagram of a rotating target for a low-scattering monoenergetic neutron generation and method according to the present invention.

[0026] Figure 3 This is a schematic diagram illustrating the circular motion decomposition principle of a low-scattering monoenergetic neutron generation and method according to the present invention. Detailed Implementation

[0027] The present invention will be further described below with reference to specific embodiments. The illustrative embodiments and descriptions herein are used to explain the present invention, but are not intended to limit the present invention.

[0028] like Figure 1 As shown, the present invention includes a target, a target tube, a KF-CF flange adapter, a bellows, and an electric actuator assembly; the rear end of the target is connected to one end of the target tube, the other end of the target tube is connected to one end of the bellows via the flange adapter, the other end of the bellows is connected to the beamline of the accelerator, and the electric actuator assembly is disposed on the outside of the bellows to support and rotate the KF-CF flange adapter, thereby driving the target tube and the target to rotate;

[0029] The electric push rod assembly periodically extends and retracts, causing the bellows to bend and the target tube and target to tilt, so that the target swings in two mutually perpendicular directions. The swings in the two directions combine to form a rotational motion, which in turn causes the target point to make a circular motion around the center of the target.

[0030] The rotating target consists of a target, a target tube, a KF-CF flange adapter, a bellows, and an electric actuator.

[0031] The target undergoes a nuclear reaction with the incident particle to produce neutrons, while simultaneously sealing the vacuum and blocking charged particles. The target is a circular sheet composed of a target material and a metal substrate, welded to the target tube to maintain the vacuum.

[0032] The target tube is used to fix, support, and protect the target. The main body of the target tube is a metal pipe that maintains vacuum and low neutron scattering, with the target and KF flange interfaces at both ends. The KF flange facilitates the replacement of the target and target tube.

[0033] The KF-CF flange adapter is used to connect the target tube and the bellows. The target tube uses a KF flange, while the bellows uses a CF flange for easier welding of the electric actuator. The KF-CF flange adapter connects the two. The main body is a metal pipe that maintains a vacuum, with KF flanges at one end and CF flanges at the other.

[0034] Bellows are used in ultra-high vacuum systems to achieve bending, expansion, and eccentricity, requiring reliable sealing performance and long service life. The main body is a flexible metal tube with CF flanges at both ends. The left flange is used to connect to the KF-CF flange adapter pipe, and the right flange is used to connect to the accelerator beamline.

[0035] The electric actuator assembly is used to support and rotate the KF-CF flange adapter pipe, thereby driving the target tube and target to rotate. The electric actuator mainly consists of a motor, actuators, and a transmission device. The transmission device converts the rotational motion of the motor into linear motion, using the motor's forward and reverse rotation to complete the actuator action. The electric actuator assembly consists of four electric actuators, parallel to the bellows, surrounding it at 90-degree intervals. Both ends are fixed to the flanges on both sides of the bellows, with the left side connected via a universal joint. Since the main body of the bellows is a flexible metal hose, it cannot support other parts. The electric actuator assembly, fixed to the bellows flange with sufficient strength, provides support and fixation. When the electric actuators extend or retract, the bellows flange tilts, causing the target tube and target to deviate from their central position. During the periodic extension and retraction of the electric actuators, the target tube and target oscillate back and forth around the central position with the same period. The oscillation of the target in two mutually perpendicular directions combines to form rotational motion.

[0036] Figure 2 The relationship between the extension and retraction of the electric actuator and the target's motion is illustrated using the target's movement in one direction as an example. The red horizontal line in the diagram represents a charged particle beam hitting the target at point B. When the electric actuator is in its initial position and the bellows is not bent, this line also connects the centers of the target, the target tube, and the bellows. At this time, the target's center is at point B. The red vertical line represents the surface of the bellows where its flange connects to the electric actuator when it is not bent. It is perpendicular to the center line, intersecting at point O, and its distance from the target center is L. There is an electric actuator above and below the center line. When the upper actuator retracts and the lower actuator (its endpoint is located at point A in the diagram, a distance R from point O) extends simultaneously, the bellows flange tilts upwards to the black line OA' (tilt angle θ1), causing the bellows to bend upwards, and the target tube and target to tilt upwards. At this time, the center line connecting the three tilts to the black line OB' (tilt angle θ2), perpendicular to OA'. Since θ1 is usually very small in practical applications, the target's horizontal motion is ignored, and only the target's vertical motion is considered. At this point, the target's center is at point B', while the charged particle beam remains in position. Therefore, the firing point moves to below the target's center. The electric actuator extends and retracts back and forth, causing the firing point to swing up and down around the target's center. This combination with the swing perpendicular to the paper's plane creates a circular motion of the firing point around the target's center, achieving the purpose of this invention. Geometrically, θ1 = θ2, and the relationship between the distances r1 and r2 that point A moves is shown in the following equation.

[0037]

[0038] Therefore, the electric actuator's extension and retraction movement with a distance of 2*r1 causes the target point to move in a circle with a radius of r2 around the target center.

[0039] by Figure 3Let's take two mutually perpendicular linear reciprocating motions as an example to illustrate that they combine to form circular motion. In the diagram, the circle represents the trajectory of the target point's clockwise circular motion. The dashed line represents the starting position, and the solid line represents the target point's current position; the angle between them is φ. Uniform circular motion can be decomposed into two mutually perpendicular linear sinusoidal motions and cosine motions. In the diagram, this is decomposed into a sinusoidal motion in the x-direction and a cosine motion in the y-direction. When the target point moves to the position indicated by φ, the phase of the corresponding x and y direction motions is consistent with φ. If the target point performs uniform circular motion with a period of T, the relationship between its coordinates in the x and y directions and time t is shown in the following equation.

[0040]

[0041] The relationship between the endpoint coordinates of the electric actuators in the x and y directions and time t is shown in the following formula. Two electric actuators opposite each other in the same direction are out of phase.

[0042]

[0043] It can be seen that the period of the circular motion of the firing point is consistent with the period of the electric actuator. By adjusting the range of motion (r1) and period of the electric actuator's endpoint, the radius and period (i.e., speed) of the circular motion of the firing point can be accurately controlled.

[0044] This invention achieves the rotating target function without affecting target firing and vacuum sealing, while maintaining a very small device mass and size, minimal neutron scattering, and no impact on the monoenergetic neutron monochromaticity. Furthermore, it features a simple structure, low cost, and ease of use and maintenance.

[0045] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A low-scattering monoenergetic neutron generating device, characterized in that, It includes a target, a target tube, a KF-CF flange adapter, a bellows, and an electric actuator assembly; the rear end of the target is connected to one end of the target tube, the other end of the target tube is connected to one end of the bellows via the flange adapter, the other end of the bellows is connected to the beamline of the accelerator, and the electric actuator assembly is located outside the bellows to support and rotate the KF-CF flange adapter, thereby driving the target tube and the target to rotate; The electric push rod assembly periodically extends and retracts, causing the bellows to bend and the target tube and target to tilt, so that the target swings in two mutually perpendicular directions. The swings in the two directions combine to form a rotational motion, which in turn causes the target point to make a circular motion around the center of the target.

2. The low-scattering monoenergetic neutron generating device according to claim 1, characterized in that, The target is a circular thin sheet composed of a target material and a metal substrate, which is welded and fixed to one end of the target tube. It is used to seal the vacuum, block charged particles, and react with incident particles to produce neutrons.

3. The low-scattering monoenergetic neutron generating device according to claim 1, characterized in that, The corrugated pipe is a flexible metal tube, and CF flanges are provided at both ends of the corrugated pipe.

4. The low-scattering monoenergetic neutron generating device according to claim 1, characterized in that, The electric actuator assembly includes four electric actuators, which achieve linear reciprocating motion under electric drive.

5. The low-scattering monoenergetic neutron generating device according to claim 4, characterized in that, The electric actuators are parallel to the bellows and are evenly distributed around the bellows at 90-degree intervals. Among the four electric actuators, the extension and retraction movements of the two electric actuators on the same axis are opposite in phase.

6. A control method for a low-scattering monoenergetic neutron device, used to execute the low-scattering monoenergetic neutron generating device according to any one of claims 1-4, characterized in that, Includes the following steps: (1) Connect the rotating target assembly, consisting of the target, target tube, KF-CF flange adapter, bellows and four electric push rods, to the accelerator beamline to ensure the CF flange at both ends of the bellows is sealed and to maintain the ultra-high vacuum environment of the target area and the beamline. (2) Based on the requirements for monoenergetic neutron production, the radius r and period T of the circular motion of the target point around the target center are set. Based on the radius r and period T, the extension and retraction motion parameters of the four electric push rods are calculated. The electric push rods on two mutually perpendicular axes correspond to the x and y directions of the circular motion, respectively. The extension and retraction phases of the two electric push rods on the same axis are opposite. (3) Control the four electric push rods to periodically extend and retract according to the set extension and retraction motion parameters, so that the bellows bends and the target tube and target tilt. By combining the sinusoidal motion of the electric push rod in the x direction with the cosine motion of the electric push rod in the y direction, the target point is driven to make a uniform circular motion with a period T around the target center with a radius of r. (4) Monitor the neutron scattering intensity of the device in real time. If the scattering intensity exceeds the preset threshold, adjust the extension and retraction range or period of the electric push rod to optimize the uniformity of the target trajectory, reduce the additional scattering caused by the unstable movement of the target and surrounding components, and maintain the monochromaticity of the monoenergetic neutron.

7. The control method for the low-scattering monoenergetic neutron device according to claim 5, characterized in that, In step (2), the telescopic motion parameters of the electric push rod include the telescopic amplitude and frequency. The telescopic amplitude is proportional to the radius r of the circular motion of the target point, and the frequency corresponds to the reciprocal of the period T.

8. The control method for the low-scattering monoenergetic neutron device according to claim 5, characterized in that, In step (3), the rotational motion of the electric motor is converted into linear extension and retraction motion through the transmission device of the electric push rod. The extension and retraction of the push rod are controlled by the forward and reverse rotation of the electric motor, so as to realize the oscillation synthesis of the target in the x and y directions.

9. The control method for the low-scattering monoenergetic neutron device according to claim 5, characterized in that, The radius and period of the circular motion of the firing point around the target center are controlled by adjusting the range of motion and extension period of the electric push rod end.

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