Flight tube structure of magnetic confinement fusion fast neutron spectrometer

Abstract

The invention relates to a flight tube structure of a magnetic confinement fusion fast neutron spectrometer, and belongs to the technical field of magnetic confinement fusion fast neutron spectrometers. The invention aims to provide a flight tube structure of a magnetic confinement fusion fast neutron spectrometer aiming at the problems in the prior art, the flight tube structure comprises a plurality of flight tube sections which are connected in sequence, and a plurality of hollow cylindrical collimation blocks are arranged in the flight tube sections and are used for absorbing and collimating neutrons. According to the flight tube structure of the magnetic confinement fusion fast neutron spectrometer, flexible system building can be achieved, the system complexity is low, and the neutron absorption efficiency of different energy sections is higher.

Description

Technical Field

[0001] This invention relates to a flight tube structure for a magnetic confinement fusion fast neutron spectrometer, belonging to the technical field of magnetic confinement fusion fast neutron spectrometers. Background Technology

[0002] Controlled nuclear fusion is considered a clean, safe, and sustainable "ultimate energy source." The linear field inverse fusion device, as an innovative magnetic confinement scheme, primarily produces fast neutrons at 2.45 MeV and 14.1 MeV. A neutron spectrometer is used to measure the neutron energy spectrum and flux produced by the device.

[0003] Defects and shortcomings of existing technology: 1. Existing neutron spectrometers mostly use a single-piece flight tube design, which is not flexible enough when adjusting the neutron flight distance and requires re-manufacturing the flight tube, wasting financial and material resources. The segmented design of this patent can effectively solve this problem and also help reduce the influence of secondary X-rays.

[0004] 2. Existing neutron spectrometer flight tubes are entirely sealed structures, requiring a vacuum in the neutron flight channel to ensure efficient passage of low-energy neutrons. However, this design suffers from complex vacuum structures and high costs. In fusion devices, the primary objective is to measure fast neutrons, which have sufficiently high passage efficiency in air, eliminating the need for vacuuming. The flight tube design of this invention eliminates the need for vacuuming, significantly reducing manufacturing difficulty and costs without compromising measurement results.

[0005] 3. In neutron spectrometer flight tubes, the shielding structure is usually an integral unit, which is costly and difficult to manufacture, and is often made of a single material. This patent uses multiple shielding blocks inside each flight tube, reducing manufacturing difficulty and cost. Furthermore, each shielding block is made of multiple materials, achieving better shielding effect with less material. Summary of the Invention

[0006] The purpose of this invention is to address the problems existing in the prior art by providing a flight tube structure for a magnetic confinement fusion fast neutron spectrometer.

[0007] The technical solution provided by this invention to solve the above-mentioned technical problems is: a flight tube structure for a magnetic confinement fusion fast neutron spectrometer, comprising several flight tube segments connected in sequence, wherein several hollow cylindrical collimating blocks are provided in the flight tube segments for neutron absorption and collimation.

[0008] A further technical solution is that the collimation block is composed of a material capable of absorbing neutrons.

[0009] A further technical solution is that the collimation block includes a fast neutron moderation layer, a fast neutron absorption layer, and a secondary gamma shielding layer arranged sequentially.

[0010] A further technical solution is to place a high-Z metal sheet between two adjacent flight tube sections to reduce the impact of generated gamma rays on the detector.

[0011] A further technical solution is to connect adjacent flight tube sections using flanges.

[0012] A further technical solution is that the flange has a total of six holes, four of which are used for fixing and locking, and two of which are used for laser collimation.

[0013] A further technical solution is to gradually decrease the diameter of several flight tube sections from front to back.

[0014] A further technical solution is to coat the outer wall of the flight tube section with a layer of polyethylene.

[0015] A further technical solution is that the flight tube segment is an aluminum tube segment.

[0016] The present invention has the following beneficial effects: 1. Modular design and maintainability: Abnormal individual flight tube segments can be removed and replaced individually, reducing maintenance costs and difficulty; traditional flight tubes are integral structures, resulting in high maintenance and repair costs. The mounting flanges of the flight tube segments provide conditions for laser alignment and laser mounting holes.

[0017] 2. The collimator features a multi-layered design, specifically optimized for fast neutrons in nuclear fusion. This layered design effectively reduces the weight and volume of the shielding material, achieving optimal fast neutron shielding efficiency for the same mass or volume. The thickness of each layer needs to be tailored to the specific energy spectrum of the fast neutrons.

[0018] 3. The collimation block can be quickly adjusted according to the measurement environment, enabling rapid optimization of the collimation structure. This increases the versatility of the flight tube under different measurement environments and improves the measurement accuracy of the neutron spectrometer. Traditional flight tubes have a single-material, monolithic collimation structure, which is difficult to optimize and adjust, requiring custom fabrication and lacking flexibility.

[0019] 4. Unlike conventional flight tubes with complex structures that require vacuuming, this invention uses non-vacuum components to build the flight tube due to the characteristics of the object being measured. This effectively saves costs and reduces system complexity without affecting the measurement results.

[0020] 5. Composition of the collimator: Each collimator is made of multiple neutron-absorbing materials to absorb neutrons of different energies, which solves the problem that conventional flight tubes have low absorption efficiency for neutrons of a certain energy using a single material. Attached Figure Description

[0021] Figure 1This is a schematic diagram of the structure of the present invention; Figure 2 This is a structural schematic diagram of the flight tube section; Figure 3 This is a schematic diagram of the collimator's structure; Figure 4 This is an exploded view of the collimation block.

[0022] The diagram shows: 1-flight tube section, 2-collimating block, 3-flange, 4-fast neutron moderation layer, 5-fast neutron absorption layer, and 6-secondary gamma shielding layer. Detailed Implementation

[0023] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for 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 invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0025] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can also refer to a mechanical connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0026] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0027] like Figures 1-4As shown, the present invention discloses a flight tube structure for a magnetic confinement fusion fast neutron spectrometer, comprising several flight tube segments 1 connected in sequence. The diameter of each flight tube segment decreases gradually from front to back, thereby reducing potential interference with straight-line neutrons and lowering the probability of weak scattering or absorption of the straight-line neutron beam. Each flight tube segment 1 contains several hollow cylindrical collimating blocks 2 for neutron absorption and collimation. The main body of each flight tube segment 1 is composed of aluminum tubing, and the collimating blocks 2 are composed of a material capable of neutron absorption.

[0028] In this embodiment, the collimator 2 within the flight tube section 1 is composed of multiple multilayer absorbers and composite multilayer heterogeneous absorbers, allowing for more refined blocking optimization for neutrons in different energy ranges. This significantly improves the blocking efficiency for stray neutrons in specific energy ranges, offering high flexibility and enabling optimization of spectrometer performance. Different materials have optimal absorption cross-sections for different energy neutrons (e.g., B-10 for thermal neutrons, Cd for ultrathermal neutrons, and W for fast neutrons), and their combination can efficiently intercept stray neutrons over a wider energy range. This significantly improves the overall shielding performance (neutron + gamma), making it particularly suitable for high-throughput or wide-spectrum neutron source environments, specifically as follows: Figure 3 and Figure 4 As shown, the collimation block includes a fast neutron moderation layer 4, a fast neutron absorption layer 5, and a secondary gamma shielding layer 6 arranged sequentially.

[0029] In this embodiment, the collimating block 2 inside the flight tube section 1, while ensuring the size of the central through hole, is designed with a thicker absorbing wall near the tube wall (the area where stray neutrons are more likely to pass through), and uses a material with higher absorption efficiency to effectively intercept off-axis neutrons.

[0030] In this embodiment, a high-Z metal sheet is provided between two adjacent flight tube sections, which can effectively reduce the influence of secondary gamma rays on the measurement results and significantly improve the signal-to-noise ratio of the measurement results.

[0031] In this embodiment, as Figure 2 As shown, adjacent flight tube sections 1 are connected by flanges 3. There are a total of six holes on the flanges 3, four of which are used for fixing and locking, and two symmetrical holes are reserved for laser collimation.

[0032] In this embodiment, the outer wall of the flight tube section 1 is covered with a layer of polyethylene for slowing down and absorbing scattered neutrons in the environment, so as to reduce the impact of scattered neutrons in the environment on the spectrometer and improve the signal-to-noise ratio of the spectrometer.

[0033] The above description is not intended to limit the present invention in any way. Although the present invention has been disclosed through the above embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A flight tube structure for a magnetic confinement fusion fast neutron spectrometer, characterized in that, It includes several flight tube segments connected in sequence, and each flight tube segment is provided with several hollow cylindrical collimating blocks for neutron absorption and collimation.

2. The flight tube structure of a magnetic confinement fusion fast neutron spectrometer according to claim 1, characterized in that, The collimation block is made of a material capable of absorbing neutrons.

3. The flight tube structure of a magnetic confinement fusion fast neutron spectrometer according to claim 1, characterized in that, The collimation block includes a fast neutron moderation layer, a fast neutron absorption layer, and a secondary gamma shielding layer arranged sequentially.

4. The flight tube structure of a magnetic confinement fusion fast neutron spectrometer according to claim 1, characterized in that, A high-Z metal sheet is installed between two adjacent flight tube sections.

5. The flight tube structure of a magnetic confinement fusion fast neutron spectrometer according to claim 1, characterized in that, Adjacent flight pipe sections are connected by flanges.

6. The flight tube structure of a magnetic confinement fusion fast neutron spectrometer according to claim 1, characterized in that, The flange has a total of six holes, four of which are used for fixing and locking, and two of which are used for laser alignment.

7. The flight tube structure of a magnetic confinement fusion fast neutron spectrometer according to claim 1, characterized in that, The diameter of several flight tube sections decreases gradually from front to back.

8. The flight tube structure of a magnetic confinement fusion fast neutron spectrometer according to claim 1, characterized in that, The outer wall of the flight tube section is covered with a layer of polyethylene.

9. The flight tube structure of a magnetic confinement fusion fast neutron spectrometer according to claim 1, characterized in that, The flight tube section is an aluminum tube section.

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