Laser spectrum detection method and device for scanning and analyzing Tokamak wall surface elements

Abstract

The invention discloses a laser spectrum detection method and device for scanning and analyzing Tokamak wall surface elements, and the method comprises the steps: guiding laser into an optical fiber, transmitting the laser transmitted by the optical fiber to a detection box, guiding the laser into a to-be-measured point position through the detection box, the laser guided into the position of the point to be measured interacts with the surface wall component to form laser-induced plasma; and collecting and analyzing the spectrum radiated outwards by the laser-induced plasma to obtain the surface element composition and content information of the measured material. According to the invention, the laser is coupled into the optical fiber, and the bendability of the optical fiber is utilized, so that the detection method for in-situ large-range scanning analysis of Tokamak wall surface elements with large-area (10-meter magnitude) scanning capability is realized, and element distribution of PFCs with special geometrical shapes can be diagnosed.

Description

Technical Field

[0001] The invention relates to the technical field of tokamak wall element detection and analysis, and in particular to a laser spectrum detection method and a detection device for scanning and analyzing tokamak wall surface elements. Background Art

[0002] In a tokamak fusion device, plasma facing wall components (PFCs) are bombarded by steady-state / transient heat and particle flows from the core / edge plasma, and plasma-wall interaction (PWI) inevitably occurs, leading to many problems such as wall etching, impurity deposition, fuel retention, and reduced plasma confinement performance. At the same time, this process will also cause defects in PFCs and affect the stability of the material surface and matrix. Especially in the divertor operation mode, the central plasma entering the boundary layer will form a strong particle flow and heat flow and shoot toward the divertor target along the open magnetic field lines, and produce strong etching, deposition, fuel retention and other interaction processes with it, seriously affecting the service life of the divertor. At the same time, some of the etched materials become impurities, pollute the plasma, cause energy radiation loss and reduce plasma confinement performance, and have a negative impact on the tokamak plasma confinement performance and high-parameter steady-state operation. Diagnosing the surface elements and their changes of Tokamak PFCs over a large area is a direct method to study and deeply understand the PFCs wall etching, impurity deposition, and material migration behavior. It is also an effective way to trace the PWI physical process, understand the PWI physical mechanism, and then develop effective control and mitigation of the impact of fusion plasma on PFCs. In-depth understanding of the above PWI problems is important for improving Tokamak plasma confinement and high-parameter steady-state operation. Optical diagnostic technology based on laser spectroscopy has been applied in Tokamak nuclear fusion devices and has become one of the key technical means to alleviate and solve PWI problems.

[0003] At present, the diagnosis of the surface elements of PFCs in a tokamak fusion device is usually an off-site diagnosis, that is, after the tokamak fusion device is opened, the PFCs are removed and then taken back to the laboratory for analysis. The main off-line analysis methods currently include nuclear reaction analysis, secondary ion mass spectrometry, accelerator mass spectrometry, X-ray electron spectroscopy, glow discharge emission spectroscopy, thermal desorption mass spectrometry and other technologies. Off-site analysis will introduce error sources during the sampling and transportation of samples, thereby affecting the analysis results. At the same time, for PFCs with a water-cooled structure, it is difficult to remove the PFCs for off-site analysis in actual operation, and the cold PFCs of the fusion device are usually large in size, and conventional off-site diagnostic techniques are also difficult to diagnose them. In addition, some off-site diagnostic technologies have expensive and complex equipment, such as accelerator mass spectrometry, secondary ion mass spectrometry and other technologies, and conventional off-site diagnostic analysis technologies are complex to operate and are not suitable for in-situ analysis in a small space such as a tokamak, and are difficult to develop into in-situ diagnostic methods. Laser induced breakdown spectroscopy (LIBS) is based on laser induced plasma combined with emission spectroscopy. Thanks to its advantages in optical diagnostic technology, it has the ability to in situ diagnose the surface elements of tokamak PFCs and has been used for surface element diagnosis of PFCs.

[0004] Generally speaking, the diameter of the vacuum chamber of a medium-sized tokamak fusion device is several meters, so the total length of the PFCs arranged in the field can reach 10 meters or even tens of meters. As mentioned above, diagnosing the surface elements and their changes of tokamak PFCs over a large area is the physical process of tracing the source of PWI, which requires LIBS technology to have the ability to diagnose tokamak PFCs in large spatial areas (on the order of 10 meters).

[0005] At present, conventional LIBS technology for diagnosing PFCs generally uses multiple optical mirrors to transmit the light path. The technical approach of changing the transmission angle between the mirror and the laser beam can be used to achieve spatial scanning diagnosis within a certain area. However, this technology has the following disadvantages:

[0006] First, due to the limitations of the size of the reflector and the laser beam focusing lens, although this technical approach can achieve PFCs scanning diagnosis within a certain spatial area (centimeter to 10 centimeters), it is difficult to achieve PFCs diagnosis at the meter level.

[0007] Second, LIBS using mirrors has difficulty in delivering the laser beam to locations with heterogeneous geometries, making it difficult to perform spatially resolved diagnosis of PFCs with heterogeneous geometries such as divertors.

[0008] Therefore, in view of the need for large-scale wall surface element diagnosis in the Tokamak fusion device and the pain points encountered by the current conventional LIBS technology, it is necessary to develop an in-situ large-scale scanning and analysis method for the detection of Tokamak wall surface elements with large-area (10-meter level) scanning capability. In view of this, this patent application is filed. Summary of the invention

[0009] In order to solve the above problems, the purpose of the present invention is to provide a laser spectroscopy detection method and detection device for scanning and analyzing the elements on the surface of a tokamak wall, realizing an in-situ large-scale scanning and analysis detection method for the surface of a tokamak wall with a large-area (on the order of 10 meters) scanning capability, providing a more effective, convenient and efficient diagnostic technology for the global surface element analysis of PFCs in tokamak fusion devices and PWI physics research.

[0010] The first object of the present invention is to provide a laser spectrum detection method for scanning and analyzing elements on the surface of a tokamak wall, which is implemented by the following technical scheme:

[0011] A laser spectrum detection method for scanning and analyzing elements on a tokamak wall surface, comprising:

[0012] The laser is introduced into the optical fiber, the laser transmitted by the optical fiber is transmitted to the detection box, the laser is introduced to the position of the point to be measured through the detection box, and the laser introduced to the position of the point to be measured interacts with the wall component to form a laser induced plasma;

[0013] The spectrum of outward radiation from the laser-induced plasma is collected and analyzed to obtain information on the elemental composition and content on the surface of the material being tested.

[0014] In the present invention, the laser is coupled to the optical fiber, and the bendability of the optical fiber is utilized to solve the limitation that the existing LIBS technology cannot completely scan the distribution of impurity deposition elements and fuel retention elements on the surface of the entire poloidal and annular PFCs (covering a 10m detection area) of the Tokamak, and obtain the in-situ large-scale scanning capability of a large area (on the order of 10 meters). At the same time, thanks to the bendability and light transmission characteristics of the optical fiber, the present invention can diagnose the element distribution of special geometric PFCs in the Tokamak inner wall devices such as divertors, and the optical fiber can be replaced in length according to demand to achieve scanning measurement of a larger area. The surface element composition and content information of the measured material at different positions can be obtained by moving the detection box to different positions.

[0015] In an optional embodiment, the detection box includes: a laser ablation optical path and a spectrum collection optical path integrated therein, the laser ablation optical path and the spectrum collection optical path adopt a coaxial configuration so that the laser ablation point and the spectrum collection point are fixed during the detection process, so that the spectrum fluctuation obtained from the measured material is reduced when detecting at different positions.

[0016] A necessary condition for the realization of LIBS diagnostic technology is that the point where the LIBS spectrum is collected must coincide with the laser ablation point, so that the spectrum signal stimulated by the LIBS technology can be collected and an effective LIBS signal can be obtained. Therefore, for the conventional LIBS technology to diagnose PFCs, when changing the transmission angle of the reflector and the laser beam to achieve a certain area of ​​diagnostic capability, it is necessary to synchronously modify the overlap of the spectrum collection point and the ablation point while changing the laser ablation point (the size of the ablation point is usually in the order of millimeters or sub-millimeters), which will inevitably increase the difficulty of measurement; in addition, changing the transmission angle of the reflector and the laser beam will cause the spatial morphology of the laser beam irradiated to the PFCs to change, such as changing from a circle to an ellipse, which will make it difficult to obtain a stable LIBS spectrum using this technical approach. More importantly, it is difficult to correlate the LIBS spectra of different measurement points, which makes subsequent data analysis extremely difficult.

[0017] In order to solve this problem, the present invention integrates the ablation optical path and the spectrum collection optical path into a detection box. The laser ablation optical path and the spectrum collection optical path adopt a coaxial configuration, so that the laser ablation point and the spectrum collection point are fixed and overlapped during the detection process, avoiding the spectral instability and incomparability caused by the deviation between the laser ablation point and the spectrum collection area and the change of the laser beam morphology in the conventional LIBS large-range scanning measurement of PFCs, and solving the technical problem that LIBS spectra at different measurement points are difficult to correlate.

[0018] The second object of the present invention is to provide a laser spectrum detection device for scanning and analyzing the elements on the surface of a tokamak wall. First, the laser beam emitted by a high-energy pulse laser is expanded, combined with a focusing lens to focus the laser beam to 600um, and then coupled and introduced into the laser input end of the laser transmission optical fiber; the laser transmission optical fiber transmits the laser to a probe box, and outputs the laser through the laser output end of the laser transmission optical fiber; the output laser is collimated and focused onto the tokamak wall component (the sample to be measured), and interacts with the tokamak wall component to form a laser-induced plasma; in this process, a coaxial collection optical path system in the probe box is used to collect the spectrum radiated outward by the laser-induced plasma, and analyze it to obtain the surface element composition and content information of the material to be measured.

[0019] Specifically, the detection device of the present invention comprises:

[0020] A laser source for generating high-energy pulsed laser;

[0021] A laser transmission optical fiber is connected to the laser source and is used for transmitting the pulsed laser in a bendable and long-distance manner. The laser is connected to the laser inlet of the detection box through the transmission optical fiber for subsequent formation of laser-induced plasma. At the same time, the laser is coupled to the laser transmission optical fiber in the present invention, which also avoids the light hazard in the laser transmission using a reflector;

[0022] The detection box has a laser ablation optical path and a spectrum collection optical path integrated therein. The laser ablation optical path is used to transmit the laser to focus on the surface of the material to be tested and form a laser-induced plasma. The spectrum collection optical path is used to couple the laser-induced plasma radiation light to the optical fiber and transmit it to the spectrometer. The laser transmission optical fiber is connected to the laser inlet of the detection box. The detection box can be moved to different positions to obtain measurement and analysis at different positions.

[0023] The probe is used to contact the surface of the sample to be tested, and the probe is installed at the outlet of the detection box.

[0024] In an optional embodiment, the laser source is a picosecond laser, and a conventional nanosecond laser can also be assembled and used, and the energy of the pulse laser is greater than or equal to 30mJ;

[0025] The probe is conical, and this conical design further improves the system's detection capability for PFCs samples at special geometric structures; the length of the probe is fixed, and the distance between the collimated laser ablation point and the plasma spectrum collection point is fixed. During the measurement process, the probe is slightly in contact with the sample being measured. This design can avoid spectral fluctuations caused by different focusing depths of the lens on the laser beam during large-scale scanning and measurement of PFCs, and has the effect of improving spectral stability.

[0026] In an optional embodiment, a laser ablation optical path and a spectrum collection optical path are provided in the detection box, and the laser ablation optical path includes:

[0027] The optical fiber coupling frame is used to collimate and couple the laser output from the laser transmission optical fiber into the detection box;

[0028] A half-wave plate is used to adjust the polarization degree of the incident laser and is combined with a polarization splitter prism to split the ablation laser after the polarization degree is adjusted;

[0029] The polarization beam splitter prism is used to split the ablation laser after adjusting the polarization degree. A part of the laser light emitted from the beam splitter prism is reflected into the laser energy detector, which is used to detect the energy of the laser light reflected from the polarization beam splitter prism and the energy wavelengths between different laser pulses in situ and in real time; the other part of the laser light is transmitted into the dichroic mirror;

[0030] Laser energy detector, used to detect the energy of the laser reflected by the polarization beam splitter in situ and in real time as well as the energy fluctuation between different laser pulses;

[0031] A dichroic mirror, which is used to transmit the laser light transmitted by the polarization beam splitter prism to the focusing lens on the one hand, and to reflect the plasma emission light into the spectrum collection optical path on the other hand;

[0032] The focusing lens is used to focus the laser transmitted by the dichroic mirror to the surface of the first wall sample to generate laser-induced plasma. The plasma emission light is reflected into the spectrum collection optical path. The focusing lens can be moved forward and backward to change the size of the focused spot, realize diagnostic measurements under different spatial resolutions, and provide material element detection under different energy densities.

[0033] In an optional embodiment, the optical fiber coupling frame is a three-dimensional adjustable frame with a locking function, which is used for the subsequent alignment adjustment of the ablation laser.

[0034] In an optional embodiment, the half-wave plate is provided with two drive motors, and the two drive motors respectively drive the half-wave plate to rotate in different directions. The laser energy detector of the present invention monitors the laser energy in real time and feeds back to the control handle, and the control handle sends instructions to the drive motor to adjust the polarization angle, and the polarization angle can be adjusted in real time, and the laser energy can be precisely controlled without changing the output power of the laser source, and the spatial energy distribution of the laser spot is not changed.

[0035] In an optional embodiment, the spectrum collection optical path includes:

[0036] A reflector, used for reflecting the plasma emitted light to enter the spectrum collecting lens;

[0037] A spectrum collecting lens is used to focus the plasma emission light and make it enter the optical fiber adapter frame;

[0038] The optical fiber adapter frame adopts a three-dimensional adjustable structure to fix and adjust the collection optical fiber;

[0039] A collection optical fiber, used to collect the plasma emission light and couple it into the spectrometer;

[0040] The spectrometer is used to convert the light emitted by the plasma into photoelectricity and to image the output spectrum.

[0041] In an optional embodiment, a rangefinder is provided in the detection box for measuring the distance between the probe and the first wall sample; the rangefinder can detect and feed back the distance fluctuation between the first wall and the conical probe at the isomerism to the control handle, and ensure the stability and repeatability of the spectrum through spectrum correction;

[0042] The detection box is provided with a gas cylinder and a flow controller to provide gases of different atmospheres and different flows; while improving the trace element spectrum signal, the conical probe and the surface of the focusing lens can be cleaned of dust to avoid damage to the surface of the laser focusing device;

[0043] The detection box is provided with a camera for taking plasma images and laser ablation pits to correct the laser spectrum. The camera can also take plasma images and measure the absorption rate of different materials to laser energy to correct the laser spectrum, further ensuring the stability and repeatability of the spectrum.

[0044] In an optional embodiment, a timing controller is provided in the detection box, and the drive motor, laser energy detector, rangefinder, flow controller, camera, and spectrometer are all connected to the timing controller, and the timing controller is connected to the control handle.

[0045] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0046] The detection method and detection device provided by the present invention couples the laser into the optical fiber and utilizes the bendability of the optical fiber to solve the limitation that the existing LIBS technology cannot completely scan the distribution of impurity deposition elements and fuel retention elements on the surface of the entire poloidal and annular PFCs (covering a 10m detection area) of the tokamak, and obtains the in-situ large-scale scanning capability of a large area (on the order of 10 meters). At the same time, thanks to the bendability of the optical fiber, the present invention can diagnose the element distribution of special geometric PFCs in the tokamak inner wall devices such as the divertor and other core components of the tokamak, and the optical fiber can be replaced in length according to demand to achieve scanning measurement of a larger area. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without creative work. In the drawings:

[0048] Figure 1 This is a schematic structural diagram of the all-fiber laser spectrum detection device provided by the present invention.

[0049] Figure 2 It is a schematic diagram of the internal optical path structure of the detection box of the present invention.

[0050] Figure 3 This is an element distribution diagram obtained by using the all-fiber laser spectrum detection device of the present invention.

[0051] In the figure:

[0052] 1-laser, 2-laser transmission optical fiber, 3-detection box, 4-probe, 5-first wall, 6-first control line, 7-second control line, 8-control handle, 9-laser optical fiber coupling frame, 10-half-wave plate, 11-polarization beam splitter, 12-first drive motor, 13-second drive motor, 14-laser energy detector, 15-dichroic mirror, 16-focusing lens, 17-plasma, 18-first wall sample, 19-gas cylinder, 20-flow controller, 21-gas pipe, 22-rangefinder, 23-reflector, 24-spectral collection lens, 25-optical fiber adapter, 26-spectrometer, 27-collecting optical fiber, 28-camera, 29-control line A, 30-control line B, 31-control line C, 32-control line D, 33-control line E, 34-control line F, 35-control line G, 36-timing controller. DETAILED DESCRIPTION

[0053] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0054] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0055] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. In the absence of conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0056] In the description of the embodiments of the present application, the terms "center", "up", "down", "left", "right", "vertical", "longitudinal", "lateral", "horizontal", "inside", "outside", "front", "back", "top", "bottom", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the products of the application are conventionally placed when in use, or are the orientations or positional relationships conventionally understood by those skilled in the art. They are merely for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0057] In the description of the present invention, unless otherwise clearly specified and limited, the terms "disposed", "opened", "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0058] Embodiment 1:

[0059] like Figure 1 As shown, an all-fiber laser spectrum detection device for in-situ large-scale scanning and analysis of tokamak wall surface elements is shown. The detection device includes a laser 1, which generates high-energy pulsed laser. The laser 1 is connected to a laser transmission fiber 2. The laser emitted by the laser 1 is transmitted to a detection box 3 through the laser transmission fiber 2. The front end of the detection box 3 is provided with a probe 4. The probe 4 contacts the first wall 5 to detect the wall surface elements. The laser 1 and the detection box are connected to a control handle 8 through a first control line 6 and a second control line 7, respectively.

[0060] like Figure 2 As shown, a laser fiber coupling frame 9 is installed at the laser inlet of the detection box 3, and a half-wave plate 10 is installed at the rear end of the laser fiber coupling frame 9. The half-wave plate 10 is used to change the laser polarization angle. Two drive motors are installed on the half-wave plate 10, namely a first drive motor 12 and a second drive motor 13. A polarization beam splitter prism 11 is installed behind the half-wave plate 10. The polarization beam splitter prism 11 is used to transmit and reflect laser light and split the ablation laser light after adjusting the polarization degree. The polarization beam splitter prism 11 reflects the laser light and reaches the laser energy detector 14. The laser energy detector 14 is used to monitor the laser energy and feed it back to the control handle 8. The incident laser light from the polarization beam splitter prism 11 reaches the dichroic mirror 15. The laser light transmitted through the dichroic mirror 15 reaches the focusing lens 16. The focusing lens 16 focuses the laser light to the laser outlet of the detection box 3. The probe 4 at the front end of the detection box 3 contacts the first wall sample 18, so that the laser light and the first wall sample 18 interact to generate plasma 17. Thus, a laser ablation optical path is formed. During detection, the laser ablation point is the location where the probe 4 contacts the first wall sample 18 .

[0061] The light emitted by the plasma 17 is reflected by the spectroscope to the reflector 23, and the reflector 23 reflects the light emitted by the plasma 17 to the spectrum collection lens 24, and the spectrum collection lens 24 focuses the light emitted by the plasma 17 to the optical fiber adapter 25, and the optical fiber adapter 25 is connected to the collection optical fiber 27, and the collection optical fiber 27 couples the light emitted by the plasma 17 to the spectrometer 26, and the spectrometer 26 performs photoelectric conversion on the light emitted by the plasma 17. Thus, a spectrum collection optical path is formed. During detection, the spectrum collection point is fixed to the position where the probe 4 contacts the first wall sample 18, which coincides with the laser ablation point. The spectrum at the spectrum collection point is collected by using the spectrum collection lens 24, the optical fiber adapter 25, the collection optical fiber 27 and the spectrometer 26.

[0062] A small gas cylinder 19 is provided in the detection box 3 , and the small gas cylinder 19 provides gases of different atmospheres for the plasma 17 . The small gas cylinder 19 is connected to a flow controller 20 , and the flow controller 20 controls the gas flow. The flow controller 20 is connected to a gas pipe 21 .

[0063] A rangefinder 22 is provided in the detection box 3 for measuring the distance fluctuation between the focusing lens 16 and the first wall sample 18 . The detection box 3 is provided with a camera 28 for capturing images of the plasma 17 and laser ablation pits on the surface of the first wall sample 18 .

[0064] A timing controller 36 is also provided in the detection box 3. The first drive motor 12 and the second drive motor 13 are connected to the timing controller 36 by a control line A29; the laser energy detector 14 is connected to the timing controller 36 by a control line B30; the spectrometer 26 is connected to the timing controller 36 by a control line C31; the rangefinder 22 is connected to the timing controller 36 by a control line D32; the flow controller 20 is connected to the timing controller 36 by a control line E33; the camera 28 is connected to the timing controller 36 by a control line F34, and the timing controller 36 is connected to the control handle 8 by a control line G35.

[0065] Figure 3 This is a longitudinal distribution diagram of the elements of the first wall of the Tokamak obtained by using the detection method of the present invention. The distribution in the diagram is the distribution of the element Cr, the distribution of the element Fe, the distribution of the element C, and the distribution of the element Na.

[0066] In the embodiment of the present invention, the laser ablation optical path and the spectrum collection optical path are integrated in the detection box 3, and the optical fiber coupling frame, half-wave plate 10, polarization splitter prism 11, laser energy detector 14, dichroic mirror 15, and focusing lens 16 are designed to form a laser ablation point at the first wall sample 18. The reflector 23, spectrum collection lens 24, optical fiber adapter frame 25, collection optical fiber 27, and spectrometer 26 are designed to fix the spectrum collection point and overlap it with the laser ablation point to form a coaxial configuration, thereby solving the instability and incomparability of the spectrum and solving the technical problem that LIBS spectra at different measurement points are difficult to correlate.

[0067] At the same time, the plasma excitation optical path and the plasma emission spectrum collection optical path in the detection box of the present invention form a folded optical path, which has the advantages of stable structure, strict design, and small size of the detection box. At the same time, the device has laser energy monitoring and feedback adjustment function, focusing adjustment function, high degree of automation, and the optical fiber can be replaced in length according to needs to achieve scanning measurement of a larger area.

[0068] The above specific implementation methods further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific implementation methods of the present invention and are 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 in the scope of protection of the present invention.

Claims

1. A laser spectrum detection method for scanning and analyzing elements on the surface of a tokamak wall, characterized in that: include: The laser is introduced into the optical fiber, and the laser transmitted by the optical fiber is transmitted to the detection box, and the laser is introduced to the position of the point to be measured through the detection box, and the laser introduced to the position of the point to be measured interacts with the wall component to form a laser induced plasma; The light radiated outward by the laser-induced plasma is collected and analyzed to obtain the element composition and content information on the surface of the material being tested.

2. The laser spectrum detection method for scanning and analyzing elements on the surface of a tokamak wall according to claim 1, characterized in that: include: The detection box integrates a laser ablation optical path and a spectrum collection optical path, and the laser ablation optical path and the spectrum collection optical path adopt a coaxial configuration so that the laser ablation point and the spectrum collection point are fixed during the detection process.

3. A detection device for performing the laser spectrum detection method for scanning and analyzing the elements on the surface of a tokamak wall as claimed in any one of claims 1 to 2, characterized in that: include: A laser source, used for generating pulsed laser; A laser transmission optical fiber connected to the laser source and used for transmitting the pulsed laser; The detection box has a laser ablation optical path and a spectrum collection optical path integrated therein. The laser ablation optical path is used to transmit the laser to focus on the surface of the material to be tested and form a laser-induced plasma. The spectrum collection optical path is used to couple the laser-induced plasma radiation light to the optical fiber and transmit it to the spectrometer. The laser transmission optical fiber is connected to the laser inlet of the detection box. The detection box can be moved to different positions to obtain measurement and analysis at different positions. The probe is used to contact the surface of the sample to be tested, and the probe is installed at the outlet of the detection box.

4. The detection device according to claim 3, characterized in that: The laser source is a picosecond laser, and the energy of the pulsed laser is greater than or equal to 30 mJ; The probe is conical and has a fixed length.

5. The detection device according to claim 3, characterized in that: The detection box is provided with a laser ablation optical path and a spectrum collection optical path, and the laser ablation optical path includes: The optical fiber coupling frame is used to collimate and couple the laser output from the laser transmission optical fiber into the detection box; Half-wave plate, used to adjust the polarization degree of the incident laser; A polarization beam splitter prism, used to split the ablation laser after adjusting the polarization degree; Laser energy detector, used to detect the energy of the laser reflected by the polarization beam splitter in situ and in real time as well as the energy fluctuation between different laser pulses; A dichroic mirror, used for transmitting the laser light transmitted by the polarization beam splitter prism to the focusing lens, and for reflecting the plasma emission light into the spectrum collection optical path; The focusing lens is used to focus the laser transmitted by the dichroic mirror to focus on the surface of the first wall sample to generate laser-induced plasma, and the plasma emission light is reflected into the spectrum collection optical path.

6. The detection device according to claim 5, characterized in that: The optical fiber coupling frame is a three-dimensional adjustable frame, which is used for the collimation adjustment of the subsequent ablation laser.

7. The detection device according to claim 5, characterized in that: The half-wave plate is provided with two driving motors, and the two driving motors respectively drive the half-wave plate to rotate in different directions.

8. The detection device according to claim 5, characterized in that: The spectrum collection optical path comprises: A reflector, used for reflecting the plasma emitted light to enter the spectrum collecting lens; A spectrum collecting lens is used to focus the plasma emission light and make it enter the optical fiber adapter frame; Optical fiber adapter frame, used to fix and adjust the collection optical fiber; A collection optical fiber, used to collect the plasma emission light and couple it into the spectrometer; The spectrometer is used to convert the light emitted by the plasma into photoelectricity and to image the output spectrum.

9. The detection device according to any one of claims 5 to 8, characterized in that: The detection box is provided with a distance meter for measuring the distance between the probe and the first wall sample; The detection box is provided with a gas cylinder and a flow controller to provide gases of different atmospheres and different flows; A camera is arranged in the detection box for taking images of plasma and laser ablation pits to correct the laser spectrum.

10. The detection device according to claim 9, characterized in that: A timing controller is arranged in the detection box, and a driving motor, a laser energy detector, a rangefinder, a flow controller, a camera and a spectrometer are all connected to the timing controller.

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