A device and method for diagnosing the spectral radiation distribution of the edge line of a high-temperature plasma

Abstract

The application discloses a kind of high-temperature plasma edge line spectrum radiation distribution diagnostic device and method, the diagnostic device includes lens, optical fiber bundle and spectrometer, the lens is set on the water-cooled plate inside vacuum chamber, the field of view of the lens covers the edge region of plasma, the lens is connected with the front end of the optical fiber bundle, the front end surface of the optical fiber bundle coincides with the focal plane of the lens, the optical fiber bundle is connected with the wall of vacuum chamber by vacuum lead-through structure, and is led to vacuum chamber outside, the tail end of the optical fiber bundle is connected with the spectrometer, to collect the spectrum emitted by plasma.The application places lens in vacuum chamber, the field of view of lens can not be limited by the size and position of observation window, and the flexible characteristics of optical fiber bundle are combined, and then the position of lens can be flexibly placed, and the emission spectrum distribution of different regions of plasma can be directly observed.Meanwhile, special lens structure is designed to weaken the coating of imaging lens when wall processing glow.

Description

Technical Field

[0001] This invention relates to the field of optical diagnostic technology for magnetic confinement nuclear fusion, specifically to a diagnostic device and method for the spectral radiation distribution of the edge line of a high-temperature plasma. Background Technology

[0002] Nuclear fusion energy, with its abundant reserves, environmental friendliness, and inherent safety, holds the promise of solving future human energy needs and environmental problems. Magnetic confinement fusion, which uses a magnetic field to confine plasma, is one of the important pathways to achieve controlled nuclear fusion. Specifically, magnetic confinement fusion refers to using a special type of magnetic field to confine an ultra-high temperature plasma composed of light atomic nuclei such as deuterium and tritium and free electrons, which is in a thermonuclear reaction state, within a limited volume, causing it to undergo a large number of controlled nuclear fusion reactions and release energy. Magnetic confinement fusion devices include tokamas, stellarators, antifield pinch devices, and linear devices, etc., and their main difference lies in the method or configuration of the magnetic field used to confine the plasma.

[0003] In high-temperature plasma, the electron temperature peaks near the magnetic axis. Highly ionized impurity particles are distributed in a shell structure in the core region, while low-ionized particles are distributed in the boundary region. When the electron temperature is much higher than 1 keV, low-Z impurities are completely stripped in most of the core region, while some stripped low-Z particles accumulate in the plasma boundary region. Medium-Z impurity ions are distributed in the plasma core region in a hydrogen-like or helium-like manner, while high-Z ions retain a relatively large number of external electrons in the core region.

[0004] In experimental research on magnetic confinement fusion devices, various optical diagnostic methods are often used to observe plasma in order to obtain basic physical parameters such as electron density, electron temperature, impurity content, and discharge configuration changes during the plasma discharge process. These parameters are crucial for the accurate measurement and control of the plasma state.

[0005] Passive spectroscopy is a diagnostic method that utilizes the radiation of high-temperature plasma itself. It is an important tool for studying the transport behavior of edge plasmas. Visible light diagnostics, due to its ability to easily calibrate absolute radiative intensity, can accurately and conveniently provide measurements of impurity density distribution. In the plasma boundary region, impurity atoms are ionized by electron collisions to form ions in a low-ionization state. These impurity ions are excited by electron collisions and then transition to produce spontaneous line radiation in the visible spectrum. Due to the presence of a steep temperature gradient at the edge, a narrow shell of background impurity ion radiation (such as carbon and oxygen ions) is generated at the boundary. Passive spectroscopy, by intersecting the boundary radiation shell, measures the spatial distribution of sine integral radiative intensity. With high spatial resolution, inversion can provide information on the local radiative intensity distribution and gradient.

[0006] In equilibrium, the intensity of linear radiation caused by electron collisions can be expressed as:

[0007] in, n e For local electron density, The density of impurity ions in the +Z ion state. Let be the photon radiation coefficient. Therefore, the spatiotemporal distribution of impurity particle density in different ionization states can be calculated by using the absolute intensity of the characteristic line radiation of boundary impurity particles.

[0008] In diagnostics of measuring the edge spectral distribution of magnetically confined fusion plasma, the lens is often placed outside the observation window, which is the vacuum interface between the atmosphere and the vacuum chamber. This is a traditional diagnostic method, but the lens's field of view is limited by the size and position of the observation window, making it impossible to directly observe the emission spectral distribution of different regions of the plasma. Summary of the Invention

[0009] The purpose of this invention is to address the problem that in the diagnosis of the edge spectral distribution of magnetically confined fusion plasma, the traditional diagnostic method involves placing the lens outside the observation window, which limits the field of view of the lens due to the size and position of the observation window, making it impossible to observe the emission spectral distribution of different regions of the plasma. This invention provides a diagnostic device and method for the spectral radiation distribution of the edge line of high-temperature plasma. By embedding the lens inside the vacuum chamber, the field of view of the lens is not limited by the size and position of the observation window. Thus, by flexibly placing the lens, the emission spectral distribution of different regions of the plasma can be observed intuitively.

[0010] This invention is achieved through the following technical solution: In a first aspect, the present invention provides a diagnostic device for the spectral radiation distribution of the edge line of a high-temperature plasma, comprising a lens, an optical fiber bundle, and a spectrometer. The lens is disposed inside a vacuum chamber, and the field of view of the lens covers the edge region of the plasma. The lens is connected to the front end of the optical fiber bundle, and the front end face of the optical fiber bundle coincides with the focal plane of the lens. The optical fiber bundle is connected to the wall of the vacuum chamber through a vacuum penetration structure and leads out of the vacuum chamber. The tail end of the optical fiber bundle is connected to the spectrometer to collect the spectrum emitted by the plasma.

[0011] In the above scheme, by placing the lens inside the vacuum chamber, the lens's field of view covers the edge region of the plasma. At the same time, the lens is connected to the front end of the fiber optic bundle, and combined with the vacuum penetration structure, the fiber optic bundle is led out of the vacuum chamber. The tail end of the fiber optic bundle is connected to the spectrometer, leading the light signal emitted by the plasma to the spectrometer outside the vacuum chamber. Since the lens's field of view is not limited by the size and position of the observation window, and combined with the flexible characteristics of the fiber optic bundle, the emission spectrum distribution of different regions of the plasma can be observed intuitively by flexibly placing the lens.

[0012] As a preferred embodiment of the present invention, the lens includes a housing and an imaging lens group disposed within the housing. The housing has an entrance pupil and a protective observation window arranged at intervals at the light incident end, and the imaging lens group is located behind the protective observation window.

[0013] In magnetic confinement devices, methods such as glow discharge cleaning and wall silicide are often used to remove impurities adhering to the vacuum chamber walls to improve plasma quality. However, when a lens is placed inside the vacuum chamber, impurity particles can easily deposit on the surface of the lens's optical elements, forming a coating that reduces the light transmittance of the optical elements.

[0014] In the above scheme, since the imaging lens group is built into the housing and the entrance pupil and protective observation window are arranged sequentially and at intervals at the light incident end, the effect of glow on the coating of the imaging lens group during wall treatment can be reduced.

[0015] As a preferred embodiment of the present invention, the imaging lens group includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged sequentially, wherein the first lens is located at the light incident end and the seventh lens is located at the light emitting end.

[0016] As a preferred embodiment of the present invention, the imaging lens group further includes a total reflection prism, which is located between the first lens and the second lens, so that the optical axis of the lens is bent at a right angle.

[0017] By bending the optical axis of the lens at a right angle, the overall length of the lens can be reduced, making it easier to install and arrange in a vacuum chamber.

[0018] As a preferred embodiment of the present invention, the lens has a focal length of 55 mm, an aperture of f / 2.7, and an image height of 24.58 mm.

[0019] As a preferred embodiment of the present invention, the lens has a field of view of 23.6°, covering the edge region of the plasma.

[0020] As a preferred embodiment of the present invention, the vacuum penetration structure includes a flange connected to the vacuum chamber wall, a vacuum sealing pipe is provided through the center of the flange, and the optical fiber bundle passes through the vacuum sealing pipe and forms a seal with it.

[0021] Because the vacuum chamber is fixedly connected to the vacuum chamber wall via a flange, and the fiber optic bundle passes through the vacuum sealing pipe, forming a seal between the two, air leakage in the vacuum chamber can be avoided.

[0022] As a preferred embodiment of the present invention, the optical fiber bundle has multiple optical fibers, which are arranged in a one-dimensional manner at the front end face of the optical fibers.

[0023] As a preferred embodiment of the present invention, the core diameter of a single fiber in the fiber bundle is 0.44 mm and the numerical aperture is 0.22.

[0024] In a second aspect, the present invention provides a diagnostic method for the spectral radiation distribution of the edge line of a high-temperature plasma, utilizing the diagnostic device for the spectral radiation distribution of the edge line of a high-temperature plasma described in the first aspect, comprising: The lens is positioned inside the vacuum chamber so that its field of view covers the edge region of the plasma; Connect the lens to the front end of the fiber optic bundle, with the front end face of the fiber optic bundle coinciding with the focal plane of the lens. The optical fiber bundle is connected to the wall of the vacuum chamber through a vacuum penetration structure and led out of the vacuum chamber to bring out the light signal emitted by the plasma to the outside of the vacuum chamber. The end of the fiber optic bundle is connected to a spectrometer, and the spectra emitted by the plasma are collected by the spectrometer to obtain the radiation distribution of the plasma edge line spectrum.

[0025] Compared with the prior art, the present invention has the following advantages and beneficial effects: 1. In this invention, the lens is placed inside the vacuum chamber, and the field of view of the lens covers the edge region of the plasma. At the same time, the lens is connected to the front end of the fiber optic bundle, and the fiber optic bundle is led out of the vacuum chamber by a vacuum penetration structure. The tail end of the fiber optic bundle is connected to the spectrometer, and the light signal emitted by the plasma is led out to the spectrometer outside the vacuum chamber. Since the field of view of the lens is not limited by the size and position of the observation window, and combined with the flexible characteristics of the fiber optic bundle, the emission spectrum distribution of different regions of the plasma can be observed intuitively by flexibly placing the lens. 2. The present invention has designed a special lens optical mechanism structure to prevent plasma coating. The imaging lens group is built into the housing, and the entrance pupil and the protective observation window are arranged at intervals at the light incident end. This can reduce the effect of the glow on the coating of the imaging lens group during wall treatment, thereby protecting the imaging lens group. 3. In this invention, after the lens collects the light energy emitted by the plasma, it is transmitted to the spectrometer through an optical fiber bundle. Since the optical fiber bundle is flexible, the direction of the optical fiber bundle can be arranged well according to the position of the lens. Compared with using optical elements to construct the optical path, using an optical fiber bundle makes it easier to adjust the position of the lens. Attached Figure Description

[0026] 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: Figure 1 This is a schematic diagram of the diagnostic device for the spectral radiation distribution of high-temperature plasma edge lines in this invention. Figure 2 This is a schematic diagram of the lens optical mechanism structure in this invention; Figure 3 This is a schematic diagram of the vacuum penetration structure in this invention.

[0027] The attached diagram shows the markings and corresponding component names: 1. Lens, 2. Fiber optic bundle, 3. Vacuum penetration structure, 4. Spectrometer, 5. Plasma, 6. Flange, 7. Vacuum sealed pipe, 8. Entrance pupil, 9. Protective observation window, 10. Total reflection prism, 11-1. First lens, 11-2. Second lens, 11-3. Third lens, 11-4. Fourth lens, 11-5. Fifth lens, 11-6. Sixth lens, 11-7. Seventh lens, 12. Fiber optic head. Detailed Implementation

[0028] 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.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0030] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly indicating the number, specific order, or primary and secondary relationship of the indicated technical features.

[0031] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0032] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A exists, A and B exist simultaneously, and B exists. In addition, the character " / " in this document generally indicates that the related objects before and after it have an "or" relationship.

[0033] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0034] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces), unless otherwise explicitly specified.

[0035] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to 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.

[0036] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0037] Nuclear fusion energy, with its abundant reserves, environmental friendliness, and inherent safety, holds the promise of solving future human energy needs and environmental problems. Magnetic confinement fusion, which uses a magnetic field to confine plasma, is one of the important pathways to achieve controlled nuclear fusion. Specifically, magnetic confinement fusion refers to using a special type of magnetic field to confine an ultra-high temperature plasma composed of light atomic nuclei such as deuterium and tritium and free electrons, which is in a thermonuclear reaction state, within a limited volume, causing it to undergo a large number of controlled nuclear fusion reactions and release energy. Magnetic confinement fusion devices include tokamas, stellarators, antifield pinch devices, and linear devices, etc., and their main difference lies in the method or configuration of the magnetic field used to confine the plasma.

[0038] In experimental research on magnetic confinement fusion devices, various optical diagnostic methods are often used to observe plasma in order to obtain basic physical parameters such as electron density, electron temperature, impurity content, and discharge configuration changes during the plasma discharge process. These parameters are crucial for the accurate measurement and control of the plasma state.

[0039] Currently, in the diagnostics of measuring the edge spectral distribution of magnetically confined fusion plasma, the lens is often placed outside the observation window, and the light emitted by the plasma is collected by the lens through the observation window. However, since the location, size, and number of observation windows in the vacuum chamber are subject to certain requirements, the field of view of the lens in this diagnostic method is limited by the size and position of the observation window, making it impossible to directly observe the emission spectral distribution of different regions of the plasma.

[0040] To address the aforementioned issues, the applicant, after in-depth research, proposed a novel edge-spectral diagnostic device. This device places the lens inside a vacuum chamber and employs a specially designed lens-optical-mechanical structure to prevent plasma coating. A vacuum-guided fiber bundle structure is used to guide the light signal emitted by the plasma to a spectrometer outside the vacuum chamber. With this approach, the lens's field of view is not limited by the size and position of the observation window, allowing for flexible lens placement and direct observation of the emission spectral distribution in different regions of the plasma.

[0041] like Figure 1As shown in the embodiment of this application, a diagnostic device for the edge line spectral radiation distribution of a high-temperature plasma 5 includes a lens 1, an optical fiber bundle 2, and a spectrometer 4. The lens 1 is disposed on a water-cooled plate inside a vacuum chamber, and the field of view of the lens 1 covers the edge region of the plasma 5. The lens 1 is connected to the front end of the optical fiber bundle 2, and the front end face of the optical fiber bundle 2 coincides with the focal plane of the lens 1. The optical fiber bundle 2 is connected to the wall of the vacuum chamber through a vacuum penetration structure 3 and leads out to the outside of the vacuum chamber. The tail end of the optical fiber bundle 2 is connected to the spectrometer 4 to collect the spectrum emitted by the plasma 5.

[0042] This application places lens 1 on a water-cooled plate inside a vacuum chamber, with the field of view of lens 1 covering the edge region of plasma 5. Simultaneously, lens 1 is connected to the front end of fiber bundle 2, and combined with vacuum transmission structure 3, fiber bundle 2 is led out of the vacuum chamber. The tail end of fiber bundle 2 is connected to spectrometer 4, leading the light signal emitted by plasma 5 to spectrometer 4 outside the vacuum chamber. Since the field of view of lens 1 is not limited by the size and position of the observation window, and combined with the flexible characteristics of fiber bundle 2, the emission spectrum distribution of different regions of plasma 5 can be observed intuitively by flexibly placing the position of lens 1.

[0043] According to some embodiments of this application, the lens 1 includes a housing and an imaging lens group disposed within the housing. The housing has an entrance pupil 8 and a protective observation window 9 arranged at intervals at the light incident end. The imaging lens group is located behind the protective observation window 9. By placing the imaging lens group within the lens 1 housing and providing the entrance pupil 8, and placing the protective observation window 9 at a certain distance behind the entrance pupil 8, particles in the plasma can be isolated from the imaging lens group, thereby reducing the coating phenomenon of the imaging lens group.

[0044] It should be noted that, in order to meet the requirements for light transmission from the plasma, the protective observation window 9 needs to have high light transmittance, such as being made of high-transmittance materials like quartz glass or sapphire. The protective observation window 9 is detachably installed inside the lens housing. If the light transmittance of the protective observation window 9 decreases after a period of use and affects the measurement of the plasma edge spectrum, it can be replaced with a new protective observation window 9 by disassembly.

[0045] To improve plasma quality, glow discharge cleaning and wall silicide treatment are commonly used to remove impurities adhering to the vacuum chamber walls. After the lens 1 is placed inside the vacuum chamber, impurity particles from the discharge will deposit on the surface of the optical element of the lens 1 to form a coating. As time goes on, the deposition thickness increases, the light transmittance of the optical element will decrease, and it may even be unable to transmit optical signals, causing problems for the measurement stability of optical diagnostics.

[0046] To prevent damage to the coating of the imaging lens group in lens 1 during glow discharge (wall treatment), lens 1 is designed with an imaging mechanism positioned in front of the entrance pupil 8, the details of which are as follows: Figure 2 As shown in the diagram, there is a certain distance between the entrance pupil 8 and the protective observation window 9 to reduce the effect of glare on the coating of the imaging lens group. In principle, the greater the distance between the entrance pupil 8 and the protective observation window 9, the smaller the coating effect and the stronger the protection for the imaging lens group.

[0047] This application designs a special lens 1 optical mechanism structure to prevent plasma 5 coating, with the imaging lens group built into the housing, and entrance pupil 8 and protective observation window 9 arranged sequentially at intervals at the light incident end. This can reduce the effect of glow on the coating of the imaging lens group during wall treatment, thereby protecting the imaging lens group.

[0048] According to some embodiments of this application, the imaging lens group includes a first lens 11-1, a second lens 11-2, a third lens 11-3, a fourth lens 11-4, a fifth lens 11-5, a sixth lens 11-6, and a seventh lens 11-7 arranged sequentially, with the first lens 11-1 located at the light incident end and the seventh lens 11-7 located at the light emitting end.

[0049] It should be noted that the first lens element 11-1, the second lens element 11-2, the third lens element 11-3, the fourth lens element 11-4, the fifth lens element 11-5, the sixth lens element 11-6, and the seventh lens element 11-7 can be installed and fixed inside the lens housing using a snap-fit ​​limiting method; no special restrictions are imposed here. Furthermore, the specific shape and structure of the lens housing can be designed according to actual conditions to facilitate installation and fixation within the vacuum chamber; no special restrictions are imposed here either.

[0050] The light emitted by plasma 5 enters the first lens 11-1 through the entrance pupil 8 and the protective observation window 9. The fiber optic head 12 at the front end of the fiber optic bundle 2 is placed behind the seventh lens 11-7 to receive the light energy collected by the lens 1.

[0051] According to some embodiments of this application, the imaging lens group further includes a total reflection prism 10, which is located between the first lens 11-1 and the second lens 11-2, so that the optical axis of the lens 1 is bent at a right angle.

[0052] A total internal reflection prism 10 refers to a prism with an isosceles right-angled triangle cross-section. The first lens 11-1 and the second lens 11-2 are located on the two sides of the right angle of the total internal reflection prism 10, respectively. The working principle of a total internal reflection prism is actually based on the laws of reflection and refraction of light. When light is reflected in the same medium, its angle of reflection is equal to its angle of incidence; when light is incident from one medium perpendicular to the plane between the two media into another medium, no deflection or refraction occurs.

[0053] It's important to note that total internal reflection prisms differ from plane mirrors. Ordinary plane mirrors are made by silvering the back surface of glass. The front surface of a plane mirror, the glass surface, also reflects light. The light undergoes multiple reflections through the glass and silver surfaces, resulting in multiple images. The image formed by the first reflection from the silver surface (the primary image) is the brightest, while the others become progressively dimmer and generally go unnoticed. However, for precision optical instruments such as cameras, telescopes, and microscopes, these extraneous images must be removed; therefore, total internal reflection prisms are commonly used.

[0054] Specifically, light is incident on the total internal reflection prism 10 from the first lens 11-1. Since the incident angle is 45°, the light will be totally reflected by the total internal reflection prism 10 to the second lens 11-2, changing the direction of light propagation and causing the optical axis of the lens 1 to be bent at a right angle. This makes the overall length of the lens 1 smaller and also facilitates its arrangement in the vacuum chamber.

[0055] According to some embodiments of this application, the lens 1 is placed on a water-cooled plate inside the vacuum chamber, with a focal length of 55 mm, an aperture of f / 2.7, and an image height of 24.58 mm. It should be noted that in this example, the lens 1 is mounted on a water-cooled plate; however, depending on the measurement location, the lens 1 can also be mounted on other components inside the vacuum chamber.

[0056] According to some embodiments of this application, the field of view of the lens 1 is 23.6°, covering the edge region of the plasma 5, see... Figure 1 As shown in the image.

[0057] Field of view represents the maximum range that a lens can observe, usually expressed in angles. The larger the field of view, the wider the observation range. The relationship between field of view and focal length: Generally, the larger the field of view, the shorter the focal length.

[0058] Here are a few examples: Telephoto lenses have a field of view narrower than 40°. For instance, for a full-frame lens, a 24mm focal length has a field of view of approximately 84°. A 50mm focal length has a field of view of approximately 47°. An 85mm focal length has a field of view of approximately 28°. A 105mm focal length has a field of view of approximately 23°. A 180mm focal length has a field of view of approximately 13°.

[0059] Table I shows the optical design parameters of lens 1.

[0060] Table I: Optical Design Parameters of Lens 1

[0061] According to some embodiments of this application, the vacuum penetration structure 3 includes a flange 6 connected to the vacuum chamber wall, with a vacuum-sealed pipe 7 passing through the center of the flange 6. The optical fiber bundle 2 passes through the vacuum-sealed pipe 7 and forms a seal with it. The optical fiber bundle 2 is led out of the vacuum chamber through the vacuum penetration structure 3, thereby inputting the light energy collected by the lens 1 into the spectrometer 4 via the optical fiber bundle 2.

[0062] The fiber bundle 2 is connected to the wall of the vacuum chamber through the vacuum penetration structure 3 and led out to the outside of the vacuum chamber. Figure 3 A schematic diagram of the vacuum penetration structure 3 is shown. In this structure, the fiber optic bundle 2 is fixedly connected to the vacuum chamber wall via a flange 6, and passes through a vacuum-sealed pipe 7. A sealing element is placed between the two to seal the vacuum-sealed pipe 7 and the fiber optic bundle 2. The sealing element can be a sealant or a sealing ring, etc.

[0063] After the fiber optic bundle 2 is led out of the vacuum chamber, its tail end is connected to the spectrometer 4. The entire system uses the spectrometer 4 to collect the spectrum emitted by the plasma 5 and obtain the radiation distribution of the plasma 5 edge line spectrum. Because the fiber optic bundle 2 is flexible, its direction can be well arranged according to the position of the lens 1. Compared with using optical elements to construct the optical path, using the fiber optic bundle 2 makes it easier to adjust the position of the lens.

[0064] According to some embodiments of this application, the fiber bundle 2 has 49 optical fibers arranged in a one-dimensional manner at the fiber tip face. It should be noted that the number of optical fibers in the fiber bundle 2 can be adjusted according to actual observation needs.

[0065] According to some embodiments of this application, the core diameter of a single fiber in the fiber bundle 2 is 0.44 mm, and the numerical aperture is 0.22. The fiber core diameter refers to the diameter of the core in the optical fiber that transmits optical signals; its size significantly affects its transmission characteristics and application scenarios. The numerical aperture is an important parameter for measuring the light-receiving capability of an optical fiber. It represents the angular range of light received at the fiber end face and is usually defined as the sine of the incident light angle. The numerical aperture of an optical fiber is related to the refractive index of the core and the relative refractive index difference between the core and cladding. A larger numerical aperture results in a stronger light-receiving capability, but an excessively large numerical aperture can lead to mode distortion, affecting the fiber's bandwidth.

[0066] This embodiment provides a diagnostic method for the spectral radiation distribution of the edge line of a high-temperature plasma, utilizing the diagnostic device for the spectral radiation distribution of the edge line of a high-temperature plasma described above, including: Lens 1 was placed on a water-cooled plate inside the vacuum chamber so that its field of view covered the edge region of plasma 5. Connect lens 1 to the front end of fiber bundle 2, and make the front end surface of fiber bundle 2 coincide with the focal plane of lens 1. The optical fiber bundle 2 is connected to the wall of the vacuum chamber through the vacuum penetration structure 3 and led out to the outside of the vacuum chamber so as to lead out the optical signal emitted by the plasma 5 to the outside of the vacuum chamber. The end of the fiber bundle 2 is connected to the spectrometer 4. The spectrometer 4 collects the spectrum emitted by the plasma 5 and obtains the radiation distribution of the edge line spectrum of the plasma 5.

[0067] Because lens 1 is placed on a water-cooled plate inside the vacuum chamber, its field of view covers the edge region of plasma 5. Simultaneously, lens 1 is connected to the front end of fiber bundle 2, and, in conjunction with vacuum penetration structure 3, leads fiber bundle 2 out of the vacuum chamber. The tail end of fiber bundle 2 is connected to spectrometer 4, leading the light signal emitted by plasma 5 to spectrometer 4 outside the vacuum chamber. In this diagnostic method, because the field of view of lens 1 is not limited by the size and position of the observation window, and combined with the flexible characteristics of fiber bundle 2, the emission spectrum distribution of different regions of plasma 5 can be directly observed by flexibly positioning lens 1. Furthermore, the special optomechanical structure of lens 1 reduces the glow effect on the coating of the imaging lens group, thereby protecting the imaging lens group.

[0068] 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 diagnostic device for the spectral radiation distribution of high-temperature plasma edge lines, characterized in that, The system includes a lens, an optical fiber bundle, and a spectrometer. The lens is located inside a vacuum chamber and its field of view covers the edge region of the plasma. The lens is connected to the front end of the optical fiber bundle, and the front end face of the optical fiber bundle coincides with the focal plane of the lens. The optical fiber bundle is connected to the wall of the vacuum chamber through a vacuum penetration structure and leads out of the vacuum chamber. The tail end of the optical fiber bundle is connected to the spectrometer to collect the spectrum emitted by the plasma. The lens includes a housing and an imaging lens group placed inside the housing. The housing has an entrance pupil and a protective observation window arranged at intervals at the light incident end. The imaging lens group is located behind the protective observation window.

2. The diagnostic device for the spectral radiation distribution of high-temperature plasma edge lines according to claim 1, characterized in that, The imaging lens group includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged in sequence. The first lens is located at the light incident end, and the seventh lens is located at the light emitting end.

3. The diagnostic device for the spectral radiation distribution of high-temperature plasma edge lines according to claim 2, characterized in that, The imaging lens group also includes a total reflection prism, which is located between the first lens and the second lens to make the optical axis of the lens bend at a right angle.

4. The diagnostic device for the spectral radiation distribution of high-temperature plasma edge lines according to claim 1, characterized in that, The lens has a focal length of 55 mm, an aperture of f / 2.7, and an image height of 24.58 mm.

5. The diagnostic device for the spectral radiation distribution of high-temperature plasma edge lines according to claim 4, characterized in that, The lens has a field of view of 23.6°, covering the edge region of the plasma.

6. The diagnostic device for the spectral radiation distribution of high-temperature plasma edge lines according to any one of claims 1-5, characterized in that, The vacuum penetration structure includes a flange connected to the vacuum chamber wall, with a vacuum-sealed pipe running through the center of the flange, and the optical fiber bundle passing through the vacuum-sealed pipe and forming a seal with it.

7. The diagnostic device for the spectral radiation distribution of high-temperature plasma edge lines according to any one of claims 1-5, characterized in that, The fiber bundle has multiple optical fibers, which are arranged in a one-dimensional manner at the front end of the optical fibers.

8. The diagnostic device for the spectral radiation distribution of high-temperature plasma edge lines according to claim 7, characterized in that, The core diameter of a single fiber in the fiber bundle is 0.44 mm, and the numerical aperture is 0.

22.

9. A diagnostic method for the spectral radiation distribution of the edge line of a high-temperature plasma, utilizing the diagnostic device for the spectral radiation distribution of the edge line of a high-temperature plasma according to any one of claims 1-8, characterized in that, include: The lens is positioned inside the vacuum chamber so that its field of view covers the edge region of the plasma; Connect the lens to the front end of the fiber optic bundle, with the front end face of the fiber optic bundle coinciding with the focal plane of the lens. The optical fiber bundle is connected to the wall of the vacuum chamber through a vacuum penetration structure and led out of the vacuum chamber to bring out the light signal emitted by the plasma to the outside of the vacuum chamber. The end of the fiber optic bundle is connected to a spectrometer, and the spectra emitted by the plasma are collected by the spectrometer to obtain the radiation distribution of the plasma edge line spectrum.

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