Single particle neutral particle spectrometer and measurement method

Abstract

The application discloses a single-particle neutral particle spectrometer and a measuring method. The spectrometer comprises a vacuum chamber, a stripping chamber, an analyzing magnet, a detector array and a gas pressure feedback gas supply system. The vacuum chamber is connected with a tokamak device through a connecting pipeline. The stripping chamber is arranged in the vacuum chamber and is used for ionizing incident neutral particles into ions. The stripping chamber is connected with an elongated pipeline at both ends. The analyzing magnet is arranged in the vacuum chamber and is located at an exit end of the stripping chamber, and is used for magnetically deflecting ions exiting from the stripping chamber. The detector array is arranged in the vacuum chamber and is located on an ion deflection track of the analyzing magnet, and is used for detecting the deflected ions. The gas pressure feedback gas supply system is connected with the stripping chamber and is used for maintaining the gas pressure in the stripping chamber constant. The application guarantees that the spectrometer can realize neutral particle energy spectrum measurement with a wide energy range, high signal-to-noise ratio, high precision and high stability in a single-particle measurement scene through integrated design.

Description

Technical Field

[0001] This invention relates to the field of diagnostic technology for magnetic confinement nuclear fusion experiments, specifically to a single-particle neutral particle spectrometer and measurement method. Background Technology

[0002] In the high-temperature plasma of magnetically confined fusion, the neutral particles generated by the resonant charge exchange reaction between ions and neutral particles (such as H atoms) possess almost the same energy as the reacting ions. These neutral particles are uncharged, their trajectories are unaffected by the magnetic field, and they have a certain probability of escaping from the plasma before the next collision. Detecting these neutral particles escaping from the plasma allows for the analysis of ion and neutral particle density information within the plasma. A diagnostic tool specifically designed to measure the energy spectrum of these neutral particles is called a Neutral Particle Analyzer (NPA). The NPA is a key diagnostic tool for high-energy ion physics analysis, ion temperature measurement, neutral particle density measurement, and fusion reactor fuel density ratio (T / D) measurement. In traditional NPA designs, a strong electrostatic field is typically used to deflect ions for energy analysis; to simultaneously achieve mass and energy analysis, a strong magnetic field combined with a strong electrostatic field is generally used to deflect ions. The detection section typically places electron multiplier tubes on different deflection trajectories for counting measurements.

[0003] In many cases, the plasma contains only one isotope of hydrogen. For example, hydrogen-boron fusion plasma contains only hydrogen, and in domestic tokamak devices such as HL-3, the working gas for both the plasma and the neutral beam is deuterium during normal operation. In such situations, a magnetic field combined with an electric field analysis system only utilizes the energy spectrum analysis function of one mass channel, resulting in wasted performance. While electrostatic fields can perform energy analysis of single particles, electric field analysis has a narrow energy range, generally only capable of analyzing low-energy particles. Furthermore, electrostatic plates may experience arcing issues at high voltages and low vacuum levels (e.g., 1E-03 Pa).

[0004] In an NPA system, the outer electrons of neutral particles are stripped in the stripping chamber, transforming them into positively charged ions, which can then be deflected for analysis in the analytical unit. The stripping medium is generally either solid or gaseous. Gas stripping methods are frequently used in NPA devices due to their advantages such as low energy loss, small scattering angle, and high reliability. Typically, the stripping chamber is placed close to the analytical magnet. The stray field in the analytical magnetic field within the stripping chamber causes ions to deflect from the very beginning. This slight deflection caused by the stray field presents two problems: First, the gas stripping chamber typically has narrow, elongated pipes with very small inner diameters installed at both ends for particle collimation and pressure maintenance. The deflection caused by the stray field may cause ions to bombard the walls of these narrow pipes, resulting in ion loss. Second, because gas stripping requires a certain target thickness, the position where neutral particles become ions in the gas stripping chamber is somewhat random. This leads to differences in the starting point of ion deflection, introducing measurement errors.

[0005] The gas stripping chamber of an NPA requires a constant gas pressure. Typically, a pressure reducing valve is installed at the high-pressure gas cylinder, and an adjustable micro-leakage valve is installed at the gas inlet of the stripping chamber to achieve a stable gas supply. However, this supply structure cannot strictly maintain a constant gas pressure. For example, as gas in the high-pressure cylinder is consumed, the pressure decreases, and the pressure downstream of the pressure reducing valve will also decrease to some extent. Summary of the Invention

[0006] This invention provides a single-particle neutral particle energy spectrometer, which solves the problems of wasted system performance, low measurement efficiency, and compromised measurement accuracy caused by redundancy of the analysis system, stray magnetic field interference, and unstable working gas pressure in existing neutral particle analyzers in single-particle measurement scenarios.

[0007] This invention is achieved through the following technical solution:

[0008] In a first aspect, this application provides a single-particle neutral particle energy spectrometer, comprising:

[0009] A vacuum chamber, which is connected to the tokamak device via connecting pipes;

[0010] The stripping chamber, located within the vacuum chamber, is used to ionize incident neutral particles into ions. Both the incident and exit ends of the stripping chamber are connected to elongated pipes for particle collimation and vacuum isolation between the stripping chamber and the external environment.

[0011] An analytical magnet, which is a permanent magnet or an electromagnet, is disposed in the vacuum chamber and located at the exit end of the stripping chamber, for magnetically deflecting ions emitted from the stripping chamber.

[0012] A detector array is disposed within the vacuum chamber and located on the ion deflection trajectory of the analytical magnet, for detecting deflected ions;

[0013] And a pressure feedback air supply system, connected to the stripping chamber, for maintaining a constant air pressure inside the stripping chamber.

[0014] A further optimization is to use a high-permeability material in the stripping chamber, which is used to shield the influence of stray magnetic fields from the analytical magnet on the stripping chamber.

[0015] A further optimization is that the high magnetic permeability material is ferritic or martensitic stainless steel.

[0016] A further optimized solution is that the pressure feedback gas supply system includes:

[0017] A high-precision vacuum gauge is used to monitor the inlet air pressure of the stripping chamber and generate an air pressure signal;

[0018] A solenoid valve, installed on the air supply line, is used to control the air supply to the stripping chamber;

[0019] A feedback controller, connected to the high-precision vacuum gauge and the solenoid valve, is used to receive the air pressure signal and control the opening and closing of the solenoid valve according to the relationship between the air pressure signal and the set air pressure.

[0020] A further optimized solution includes a collimation system, which comprises:

[0021] A collimation window is provided on the wall of the vacuum chamber and is coaxial with the stripping chamber;

[0022] The laser level is mounted on a support platform via a three-dimensional adjustable bracket. The laser beam emitted by the level can pass through the collimation window and the slender pipe of the stripping chamber to achieve line-of-sight calibration during the installation process.

[0023] A further optimization is that the analytical magnet is a neodymium iron boron permanent magnet or an electromagnet.

[0024] Secondly, this application provides a measurement method applied to the above-mentioned single-particle neutral particle spectrometer, the method comprising the following steps:

[0025] The air pressure inside the stripping chamber is maintained constant through an air pressure feedback air supply system.

[0026] Neutral particles escaping from the tokamak device are allowed to enter the stripping chamber and be ionized into ions;

[0027] After the ions are magnetically deflected by the analytical magnet, the signal is collected by the detector array;

[0028] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0029] By using permanent magnets or electromagnets as analysis units, the performance waste of composite analysis systems is effectively avoided in single-particle scenarios, reducing system complexity and maintenance costs; permanent magnets do not require vacuum electrical feedthrough, fundamentally eliminating the potential risk of high-voltage arcing in a vacuum.

[0030] The stripping chamber is made of a high-permeability material, which can effectively shield the stray magnetic field of the analytical magnet, making the magnetic field strength inside the stripping chamber and the connected slender pipe approach zero. This avoids the loss caused by ions accidentally deflecting and hitting the tube wall in the early stage of generation, while ensuring that all ions deflect from the same geometric position, thus improving the accuracy of energy analysis.

[0031] An integrated air pressure feedback supply system monitors and dynamically adjusts the inlet air pressure of the stripping chamber in real time. When the pressure of the front-stage air source fluctuates, the system can quickly compensate through feedback control, thereby maintaining a constant working air pressure in the stripping chamber and ensuring the stability and reliability of the gas stripping process. Attached Figure Description

[0032] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0033] Figure 1 This is a side view of a schematic diagram of a neutral particle spectrometer provided in an embodiment of this application.

[0034] In the picture:

[0035] 1. Vacuum chamber; 2. Signal feed window; 3. Detector array; 4. Collimation window; 5. Permanent magnet; 6. Ion flight trajectory; 7. Stripping chamber; 8. Incident window; 9. Collimation partition; 10. Neutral particle flight trajectory; 11. Connecting pipe; 12. Molecular pump; 13. Vacuum inner gas pipe; 14. Gas supply window; 15. High-precision vacuum gauge; 16. Solenoid valve; 17. Adjustable micro-leakage valve; 18. Vacuum outer gas pipe; 19. Feedback controller; 20. High-precision vacuum gauge; 21. Full-range gauge; 22. Laser level; 23. Three-dimensional adjustable bracket; 24. Support platform; 25. Height adjustment stud. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0037] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0038] First, some of the technical terms used in this application will be explained to help those skilled in the art understand this application.

[0039] NPA: Neutral Particle Analyzer;

[0040] HL-3: The name of a tokamak device developed by the Southwestern Institute of Physics of China's nuclear industry;

[0041] Br: Remanence;

[0042] T / D: Tritium / Deuterium ratio;

[0043] MeV: Mega-electronvolt.

[0044] This application provides a single-particle neutral particle energy spectrometer, such as... Figure 1 As shown, it includes:

[0045] Vacuum chamber 1, which is connected to the tokamak device via connecting pipe 11;

[0046] The stripping chamber 7, disposed within the vacuum chamber 1, is used to ionize incident neutral particles into ions. The stripping chamber 7 includes a stripping chamber and slender pipes disposed at both ends thereof for collimation and vacuum isolation.

[0047] An analytical magnet, which is a permanent magnet 5 or an electromagnet, is disposed in the vacuum chamber 1 and located at the exit end of the stripping chamber 7, for magnetically deflecting ions emitted from the stripping chamber 7.

[0048] Detector array 3 is disposed inside the vacuum chamber 1 and located on the ion deflection trajectory of the analytical magnet, for detecting deflected ions;

[0049] And a pressure feedback air supply system, connected to the stripping chamber 7, for maintaining a constant air pressure in the stripping chamber 7.

[0050] This embodiment uses permanent magnets as the analysis unit, which effectively avoids the performance waste of composite analysis systems in a single particle scenario, and reduces the complexity and maintenance cost of the system; permanent magnets do not require vacuum electrical feed, which fundamentally eliminates the potential risk of high-voltage arcing in a vacuum.

[0051] The stripping chamber is made of a high-permeability material, which can effectively shield the stray magnetic field of the analytical magnet, making the magnetic field strength inside the stripping chamber and the connected slender pipe approach zero. This avoids the loss caused by ions accidentally deflecting and hitting the tube wall in the early stage of generation, while ensuring that all ions deflect from the same geometric position, thus improving the accuracy of energy analysis.

[0052] An integrated air pressure feedback supply system monitors and dynamically adjusts the inlet air pressure of the stripping chamber in real time. When the pressure of the front-stage air source fluctuates, the system can quickly compensate through feedback control, thereby maintaining a constant working air pressure in the stripping chamber and ensuring the stability and reliability of the gas stripping process.

[0053] In one embodiment, the vacuum isolation and particle injection functions between the vacuum chamber 1 and the tokamak device are achieved collaboratively through the injection window 8 and its related structures. The vacuum chamber 1 is provided with the injection window 8 to allow neutral particles escaping from the tokamak device to enter the interior of the vacuum chamber 1. This injection window 8 is a pipe extended to 20 cm to accommodate the slender injection pipe of the stripping chamber 7. To achieve precise particle collimation and maintain vacuum isolation, an isolation plate is installed on the side of the injection window 8 near the connecting pipe 11. A slender pipe with an inner diameter of 2.5-3 mm and a length of 10 cm is installed at the center of this isolation plate. This slender pipe is used for particle collimation, and due to the high flow resistance of the slender pipe to the gas, the vacuum level of the vacuum chamber 1 can be maintained at 1 × 10⁻ when the gas pressure in the stripping chamber 7 is 1 Pa. 4 This structure achieves effective vacuum isolation at the Pa level. It can be effectively used for vacuum isolation between the NPA vacuum chamber 1 and the tokamak device. To ensure system installation accuracy and alignment, the vacuum chamber 1 is connected to the support platform 24 via height adjustment studs 25, allowing for fine-tuning of height and tilt angle.

[0054] In one embodiment, the vacuum chamber 1 integrates a vacuum maintenance system and a collimation system, which work together.

[0055] The vacuum maintenance system achieves graded monitoring of the vacuum level by coordinating a full-scale gauge 21 and a high-precision vacuum gauge 20 within the vacuum chamber 1. The full-scale gauge 21 has lower measurement accuracy and is mainly used to observe the trend of vacuum level changes during evacuation. The high-precision vacuum gauge 20 has higher measurement accuracy and is mainly used to measure the precise value of the vacuum level after vacuum stabilization. To ensure the establishment and continuous maintenance of a high vacuum environment, a circular hole with a diameter of approximately 10 cm is provided in the bottom plate of the vacuum chamber 1, directly below the analytical magnet. This circular hole is connected to a molecular pump 12 via a transition pipe.

[0056] The collimation system has a collimation window 4 on the side of the vacuum chamber 1 away from the connecting pipe 11. This window is strictly coaxial with the stripping chamber 7 and the incident window 8. A laser level 22 is installed on the side of the support platform 24 near the collimation window 4. The laser level 22 is connected to the platform through a rotatable three-dimensional adjustable bracket 23.

[0057] The calibration procedure for this collimation system is as follows:

[0058] When installing the spectrometer onto the tokamak device and calibrating the neutral particle detection line of sight, the operator first opens the collimation window 4 on the vacuum chamber 1. Then, by adjusting the three-dimensional adjustable bracket 23 on the support platform 24, the angle and position of the laser level 22 are precisely adjusted so that the emitted laser beam passes through the collimation window 4 and sequentially passes precisely through the slender pipes at both ends of the stripping chamber 7 and the slender pipe on the partition of the incident window 8. Finally, the laser beam enters the vacuum chamber of the tokamak device. By measuring the spatial coordinates of at least two points of the incident laser beam in the far-field optical path, the neutral particle detection line of the spectrometer can be accurately calculated and calibrated. After calibration, during normal system operation, the collimation window 4 must be sealed with a blind flange to maintain the vacuum integrity of the vacuum chamber 1.

[0059] In one embodiment, both ends of the stripping chamber 7 are provided with slender pipes. To achieve this design, slender pipes with an inner diameter of 1.5 to 2 mm and a length of 40 to 50 mm are installed at the center of both bottom surfaces of the stripping chamber. Furthermore, a slender pipe with an inner diameter of 2.5-3 mm and a length of 10 cm is also installed on the isolation plate located at the entrance window 8 of the vacuum chamber 1. This utilizes the inherent high flow resistance of the slender pipes. When working gas is introduced into the stripping chamber 7 and its working pressure is maintained at approximately 1 Pa, this structure effectively isolates the area of ​​the stripping chamber 7 from the high vacuum environment of the main vacuum chamber 1. When the gas pressure in the stripping chamber 7 is 1 Pa, the vacuum level in the vacuum chamber 1 can reach 1 × 10⁻⁻⁻⁶. 4 The magnitude is on the order of Pa. In terms of spatial layout and magnetic circuit design, the analytical magnet adopts a C-shaped permanent magnet structure, and one side of its magnetic gap must be strictly aligned with the exit pipe of the stripping chamber 7.

[0060] In one embodiment, the stripping chamber 7 is made of a high-permeability material to address the impact of stray magnetic fields from the analytical magnet on measurement accuracy. The high-permeability material is martensitic stainless steel. This magnetic shielding design attenuates the magnetic field strength inside the stripping chamber 7 and its connected elongated pipe region to near-zero levels. This design offers two advantages: first, it prevents ions from being deflected by stray magnetic fields and bombarding the inner wall of the elongated pipe during the initial generation stage, thus reducing particle loss; second, it ensures that the physical position at which all ions begin to deflect is fixed at the exit of the elongated pipe from the stripping chamber, eliminating differences in deflection starting points caused by the randomness of ionization positions and improving the accuracy of energy analysis.

[0061] It should be noted that shielding the stray magnetic field of the analytical magnet is not limited to manufacturing the entire stripping chamber 7 using a high-permeability material. In other feasible implementations, the stripping chamber 7 can be made of austenitic stainless steel with low permeability, which is easy to weld and process; a shell made of a high-permeability material such as permalloy can be used to enclose the stripping chamber 7; or a perforated shielding plate made of a high-permeability material can be installed at an appropriate location between the stripping chamber 7 and the analytical magnet. These alternatives can all effectively attenuate the stray magnetic field, bringing the magnetic field strength within the stripping chamber 7 and the connected pipes close to zero.

[0062] In one embodiment, the analytical magnet preferably uses N54 neodymium iron boron permanent magnet material, which has high remanence (Br) characteristics, with a Br value of 1.45-1.51T. Through an optimized C-shaped magnetic circuit design, a strong magnetic field of not less than 0.9 T can be generated in the magnetic gap, thereby ensuring effective deflection and analysis of high-energy ions (e.g., protons with energies higher than tens of keV), overcoming the limitation of the narrow energy range of electrostatic analyzers. Simultaneously, in single-particle (e.g., only deuterium) measurement scenarios, the permanent magnet 5 scheme eliminates the need for a high-voltage power supply and vacuum power supply components, fundamentally eliminating the potential risk of high-voltage arcing in a vacuum, and reducing system complexity and maintenance costs. Structurally, the analytical magnet adopts a C-shaped permanent magnet structure, with one side of its magnetic gap strictly aligned with the exit pipe of the stripping chamber 7 to ensure that particles can smoothly enter the magnetic gap. In terms of mechanical support, the magnet is rigidly connected to the bottom plate of vacuum chamber 1 by two rectangular stainless steel support members with a cross-sectional dimension of 2 cm (height) × 2.5 cm (width).

[0063] In one embodiment, all detectors are in the form of scintillator-coupled silicon photomultiplier tubes or miniature photomultiplier tubes.

[0064] In one embodiment, the pressure feedback gas supply system is used to precisely maintain the working pressure of the stripping chamber 7, and includes a high-precision vacuum gauge 15, a solenoid valve 16, and a feedback controller 19. The high-precision vacuum gauge 15 is responsible for monitoring the inlet pressure of the stripping chamber 7 in real time and outputting the signal to the feedback controller 19. The feedback controller 19 is used to receive the pressure signal and compare it with a preset set pressure value in real time. Based on the comparison result, it controls the opening and closing state of the solenoid valve 16: if the current pressure is greater than the set pressure, the solenoid valve 16 is kept closed; if the current pressure is less than the set pressure, the solenoid valve 16 is opened until the current pressure reaches the set pressure. The upstream of the solenoid valve 16 is connected to the vacuum external gas pipe 18 through an adjustable micro-leakage valve 17 to achieve fine adjustment of the upstream pressure. In addition, as an equivalent alternative implementation of this pressure feedback gas supply system, the combination of the solenoid valve 16 and the feedback controller 19 can be replaced by a flow meter that can accept a set flow rate and provide real-time feedback adjustment. By monitoring and controlling the gas flow rate entering the stripping chamber 7, the goal of maintaining a constant working gas pressure within the stripping chamber 7 can also be achieved. This integrated design enables the gas supply system to automatically compensate for changes caused by fluctuations in gas source pressure or gas consumption, dynamically maintaining constant working conditions in the stripping chamber 7.

[0065] Furthermore, as an equivalent alternative implementation of this pressure feedback gas supply system, the combination of the solenoid valve 16 and the feedback controller 19 can be replaced by a flow meter capable of accepting a set flow rate and providing real-time feedback adjustment. By monitoring and controlling the gas flow rate entering the stripping chamber 7, the goal of maintaining a constant working gas pressure within the stripping chamber 7 can also be achieved.

[0066] In one specific embodiment, the single-particle neutral particle spectrometer provided in this application includes a stripping chamber 7, an analytical magnet, a detector array 3, a vacuum chamber 1, and a laser level 22 for collimation.

[0067] The stripping chamber 7 is a horizontally placed cylindrical cavity, with slender pipes of 1.5-2 mm inner diameter and 40-50 mm length installed at the center of each of its two bottom surfaces. The stripping chamber 7 is fixed at the connection between the entrance window 8 and the vacuum chamber 1. The pipe section of the entrance window 8 is extended to 20 cm, and a collimation baffle 9 is installed on the side of the pipe near the connecting pipe 11. A slender pipe of 2.5-3 mm inner diameter and 10 cm length is installed at the center of the collimation baffle 9. A circular hole is opened at the top of the stripping chamber 7, which is connected to the pressure feedback gas supply system through a circular hole on the blind plate of the gas supply window 14 and the vacuum inner gas pipe 13.

[0068] The analytical magnet is a C-shaped permanent magnet 5, made of N54 neodymium iron boron material. One side of its magnetic gap faces the exit pipe of the stripping chamber 7, and it is connected to the bottom plate of the vacuum chamber 1 by two rectangular stainless steel supports, each 2 cm high and 2.5 cm wide. The material of the stripping chamber 7 is ferritic or martensitic stainless steel.

[0069] A collimation window 4 is provided on the side of the vacuum chamber 1 away from the connecting pipe 11. A laser level 22 and a three-dimensional adjustable bracket 23 are installed on the support platform 24. The vacuum chamber 1 is equipped with a full-scale gauge 21 and a high-precision vacuum gauge 20, and is evacuated by a molecular pump 12. It is connected to the support platform 24 by a height adjustment stud 25.

[0070] Secondly, this application provides a measurement method applied to a single-particle neutral particle spectrometer as described above, the method comprising the following steps:

[0071] The air pressure inside the stripping chamber 7 is maintained constant through an air pressure feedback supply system.

[0072] Neutral particles are introduced into the stripping chamber 7 and ionized into ions;

[0073] After the ions are magnetically deflected by the analytical magnet, the signals are synchronously acquired by the measurement channel and the background channel of the detector array 3.

[0074] In a more specific embodiment, the measurement method provided in this application includes the following steps:

[0075] A pneumatic feedback gas supply system integrating a high-precision vacuum gauge 15, a solenoid valve 16, and a feedback controller 19 is used to dynamically control the working gas pressure of the stripping chamber 7 in a closed loop. The system continuously monitors the gas pressure status and compares it with the set value, maintaining stable gas pressure by adjusting the gas supply in real time, thus creating constant environmental conditions for the ionization process of neutral particles.

[0076] While maintaining stable gas pressure, neutral particles escaping from the tokamak device enter the energy dispersive spectrometer along a predetermined path. These particles sequentially pass through the collimating baffle 9 structure connecting pipe 11, the entrance window 8, and the slender pipes at both ends of the stripping chamber 7. These pipes not only collimate the particle beam but also maintain the vacuum gradient between vacuum chamber 1 and the tokamak device, and between the stripping chamber 7 region and the main cavity of vacuum chamber 1, through their high flow resistance characteristics. After entering the stripping chamber 7, the neutral particles collide with the working gas inside and are ionized into ions.

[0077] The ionized ions then enter the strong magnetic field region generated by permanent magnet 5 and move along specific ion flight trajectories 6. Under the influence of the magnetic field, the ions are deflected by the Lorentz force. Since the system is optimized for a single particle type, the deflection radius of the ion is only related to its energy, thus achieving spatial separation according to energy level. Ions of different energies will eventually bombard different positions of the detector array 3.

[0078] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A single-particle neutral particle energy spectrometer, characterized in that, include: A vacuum chamber, which is connected to the tokamak device via connecting pipes; The stripping chamber, located within the vacuum chamber, is used to ionize incident neutral particles into ions. Both the incident and exit ends of the stripping chamber are connected to elongated pipes for particle collimation and vacuum isolation between the stripping chamber and the external environment. An analytical magnet is disposed within the vacuum chamber and located at the exit end of the stripping chamber, for magnetically deflecting ions emitted from the stripping chamber; A detector array is disposed within the vacuum chamber and located on the ion deflection trajectory of the analytical magnet, for detecting deflected ions; And a pressure feedback air supply system, connected to the stripping chamber, for maintaining a constant air pressure inside the stripping chamber.

2. The single-particle neutral particle spectrometer according to claim 1, characterized in that, The stripping chamber is made of a high-permeability material, which is used to shield the stray magnetic field of the analytical magnet from the influence of the stripping chamber.

3. The single-particle neutral particle spectrometer according to claim 2, characterized in that, The high magnetic permeability material is ferritic or martensitic stainless steel.

4. The single-particle neutral particle spectrometer according to claim 1, characterized in that, The pressure feedback gas supply system includes: A high-precision vacuum gauge is used to monitor the inlet air pressure of the stripping chamber and generate an air pressure signal; A solenoid valve, installed on the air supply line, is used to control the air supply to the stripping chamber; A feedback controller, connected to the high-precision vacuum gauge and the solenoid valve, is used to receive the air pressure signal and control the opening and closing of the solenoid valve according to the relationship between the air pressure signal and the set air pressure.

5. The single-particle neutral particle spectrometer according to claim 1, characterized in that, It also includes a collimation system, which comprises: A collimation window is provided on the wall of the vacuum chamber and is coaxial with the stripping chamber; The laser level is mounted on a support platform via a three-dimensional adjustable bracket. The laser beam emitted by the level can pass through the collimation window and the slender pipe of the stripping chamber to achieve line-of-sight calibration during the installation process.

6. The single-particle neutral particle spectrometer according to claim 1, characterized in that, The analytical magnets are neodymium iron boron permanent magnets or electromagnets.

7. A measurement method, characterized in that, Applied to a single-particle neutral particle spectrometer according to any one of claims 1 to 6, the method comprises the following steps: The air pressure inside the stripping chamber is maintained constant through an air pressure feedback air supply system. Neutral particles escaping from the tokamak device are allowed to enter the stripping chamber and be ionized into ions; After the ions are magnetically deflected by the analytical magnet, the signals are collected by a one-dimensional detector array.

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