Vacuum isolation feedthrough cavity structure, diagnostic system, nuclear fusion experimental equipment and method

Abstract

The present application relates to a vacuum isolation feedthrough cavity structure, a diagnostic system, a nuclear fusion experimental device and a method, and belongs to the field of vacuum feedthrough technology. It includes: a second vacuum cavity, one end of which in the first direction abuts against the first end wall of the first vacuum cavity, and the other end in the first direction is sealed with a second end wall to form a second vacuum cavity for the transmission line to pass through; a vacuum pipe joint, which is arranged on any side wall of the second vacuum cavity, and the vacuum pipe joint is used to connect the second vacuum cavity to a vacuum forming mechanism or a vacuum detection mechanism; a transmission line sealing structure, including a first sealing structure and a second sealing structure, the first sealing structure is arranged at the junction where the transmission line passes through the first end wall; the second sealing structure is arranged at the junction where the transmission line passes through the second end wall; the transmission line sealing structure includes a sealing filler, and the sealing filler is filled in the radial gap between the transmission line and the end wall. The technical solution of the present application has a reliable sealing structure, and the structure is simple and the cost is low.

Description

Technical Field

[0001] The present application relates to the field of vacuum feedthrough technology, and in particular to a vacuum isolation feedthrough cavity structure, a diagnostic system, and a nuclear fusion experimental device and method. Background Art

[0002] Energy is one of the important issues facing the development of human society. With the large-scale exploitation of fossil energy discovered on the earth, the remaining available fossil energy is decreasing. Therefore, the exploration and utilization of renewable clean energy is one of the most urgent research topics. The renewable clean energy currently being explored and utilized in the world includes solar energy, hydropower, wind energy, tidal energy, and nuclear energy (including fusion energy and fission energy). Among the above-mentioned clean and renewable energy sources, fusion energy is one of the most challenging and promising clean energy sources.

[0003] Magnetic confinement nuclear fusion is an experimental device that is currently widely studied. It mainly uses a strong magnetic field as a closed "magnetic cage" to surround and confine high-temperature plasma. In the existing technology, different types of experimental devices such as tokamaks, stellarators, magnetic mirrors, reverse fields, and spherical rings have been developed and constructed. The laser Thomson scattering diagnostic system is a reliable means of diagnosing electron temperature and density distribution in fusion research. As a method of actively measuring the temperature and density of plasma electrons, it will not interfere with the plasma; at the same time, by changing the duration of the laser, the time resolution of the diagnosis can be greatly improved; the range of diagnostic parameters is wide, basically covering the density of various types of plasmas, from the density of magnetic confinement fusion plasma to the density of the corona plasma of inertial confinement fusion.

[0004] The Thomson scattering diagnostic system uses a laser to emit Gaussian light, which is focused to the center of the plasma through a lens. The light beam is scattered by plasma free electrons, collected by a lens, and then imaged on a fiber bundle. It is then transmitted to the outside of the experimental device through the optical fiber for photoelectric conversion and signal processing. Large-scale fusion experimental devices, especially superconducting experimental devices, require ultra-high vacuum conditions because their superconducting coils operate in an ultra-low temperature environment in the liquid helium temperature zone, while the plasma is located in a high temperature environment with a strong magnetic field background. The optical fiber near the plasma must adopt a safe and reliable feed-through sealing structure to maintain the vacuum environment of the device body.

[0005] Currently, the feedthrough sealing structure has the problems of low reliability and high cost. Summary of the invention

[0006] In view of this, the present application provides a vacuum isolation feedthrough cavity structure, a diagnostic system, a nuclear fusion experimental device and a method to solve at least one problem existing in the background technology.

[0007] To achieve the above purpose, the technical solution of this application is implemented as follows:

[0008] In a first aspect, an embodiment of the present application provides a vacuum isolation feedthrough cavity structure, which is applied to a Thomson scattering diagnostic system. The Thomson scattering diagnostic system includes a first vacuum cavity and a transmission line that transmits data from the first vacuum cavity to the outside, including:

[0009] A second vacuum cavity, one end of which in the first direction abuts against the first end wall of the first vacuum cavity, and the other end of which in the first direction is sealed with a second end wall, so as to form a second vacuum cavity for the transmission line to pass through; the first direction is the direction in which the transmission line passes out of the first vacuum cavity;

[0010] a vacuum pipe joint, arranged on any side wall of the second vacuum cavity, and used to connect the second vacuum cavity to a vacuum forming mechanism or a vacuum detecting mechanism, so as to form the second vacuum cavity by pumping air or to detect the vacuum degree of the second vacuum cavity;

[0011] A transmission line sealing structure, comprising a first sealing structure and a second sealing structure, wherein the first sealing structure is arranged at a junction where the transmission line passes through the first end wall, so that the transmission line remains sealed at the junction where the transmission line passes through the first end wall;

[0012] The second sealing structure is arranged at the junction where the transmission line passes through the second end wall, so that the transmission line remains sealed when passing through the second end wall; the transmission line sealing structure includes a sealing filler, and the sealing filler is filled in the radial gap between the transmission line and the end wall; the end wall includes the first end wall and the second end wall.

[0013] Optionally, the sealing filler is formed after a welding process is performed.

[0014] Optionally, the transmission line is an optical fiber, and the optical fiber jacket is provided with a metal protective tube; the transmission line sealing structure includes:

[0015] A first filler, which is filled between the radial gap between the optical fiber and the metal protection tube after a welding process is performed;

[0016] The second filler is filled in the radial gap between the metal protection tube and the end wall after the welding process is performed.

[0017] Optionally, the first filler is formed after a brazing process;

[0018] The second filler is formed after performing any one of the following processes: gas shielded welding, plasma arc welding, electron beam welding and laser beam welding.

[0019] Optionally, the first sealing structure and the second sealing structure further include a metal coating plated on the outer surface of the optical fiber.

[0020] Optionally, the second vacuum chamber comprises a side wall, and the side wall and the first end wall are integrally formed.

[0021] Optionally, the side wall and the second end wall are sealed and fixed to make the second vacuum chamber sealed on all sides.

[0022] Optionally, the vacuum isolation feedthrough cavity structure further includes:

[0023] The transmission line fixing plate is fixed on the inner wall of the first vacuum chamber on all sides, and a conduit for the transmission line to pass into the first vacuum chamber is fixed in the middle, and a preset structure for limiting the position of the transmission line is arranged in the conduit.

[0024] In a second aspect, an embodiment of the present application provides a Thomson scattering diagnostic system, comprising:

[0025] A first vacuum chamber having a first vacuum chamber;

[0026] A transmission line, used for transmitting data from the first vacuum chamber to the outside;

[0027] Any of the vacuum isolation feedthrough cavity structures described above.

[0028] In a third aspect, an embodiment of the present application provides a magnetic confinement nuclear fusion experimental device, including the Thomson scattering diagnostic system described above.

[0029] In a fourth aspect, an embodiment of the present application provides a method for manufacturing a transmission line sealing structure in the vacuum isolation feedthrough cavity structure described above, the method comprising:

[0030] The joint where the transmission line passes through the end wall is sealed to form a transmission line sealing structure; wherein:

[0031] Brazing is performed in the radial gap between the transmission line and the metal protection tube, and the welding temperature is lower than or equal to 600 degrees Celsius.

[0032] Optionally, the method further comprises:

[0033] After the transmission line sealing structure is formed, a sealing performance test is performed, and the sealing performance test includes:

[0034] The vacuum isolation feedthrough cavity structure is subjected to at least three hot and cold cycle processes, and a vacuum leak rate test is performed when the temperature during each hot and cold cycle reaches a preset high temperature; the preset high temperature is 240 degrees Celsius.

[0035] The vacuum isolation feedthrough cavity structure, diagnostic system, nuclear fusion experimental equipment and method provided by the embodiment of the present application include: a second vacuum cavity, one end of which in a first direction abuts against a first end wall of the first vacuum cavity, and the other end of which in the first direction is sealed with a second end wall to form a second vacuum cavity for the transmission line to pass through; the first direction is the direction in which the transmission line passes out of the first vacuum cavity; a vacuum pipe joint, which is arranged on any side wall of the second vacuum cavity, and the vacuum pipe joint is used to connect the second vacuum cavity to a vacuum forming mechanism or a vacuum detection mechanism to form the second vacuum cavity by pumping air or to detect the vacuum degree of the second vacuum cavity; a transmission line sealing structure, which includes a first sealing structure and a second sealing structure, wherein the first sealing structure is arranged at the junction where the transmission line passes through the first end wall, so that the transmission line remains sealed at the junction where the transmission line passes through the first end wall; the second sealing structure is arranged at the junction where the transmission line passes through the second end wall, so that the transmission line remains sealed at the junction where the transmission line passes through the second end wall; the transmission line sealing structure includes a sealing filler, and the sealing filler is filled in the radial gap between the transmission line and the end wall; the end wall includes the first end wall and the second end wall. It can be seen that the vacuum isolation feedthrough cavity structure, diagnostic system, nuclear fusion experimental equipment and method of the embodiment of the present application, a second vacuum cavity is arranged at the outer end of the transmission line passing through the first vacuum cavity, the second vacuum cavity forms a second vacuum cavity, and a transmission line sealing structure is arranged at the end wall where the transmission line passes through the first vacuum cavity, and at the end wall where the transmission line passes through the second vacuum cavity, the transmission line sealing structure includes a sealing filler, and the sealing filler is filled in the radial gap between the transmission line and the end wall; since the two end walls through which the transmission line passes are provided with the transmission line sealing structure, a two-level seal is formed, and the second vacuum cavity also protects the vacuum degree of the first vacuum cavity, so the sealing structure is reliable, the structure is simple, and the cost is low. Therefore, the vacuum isolation feedthrough cavity structure, diagnostic system, nuclear fusion experimental equipment and method of the embodiment of the present application have a reliable sealing structure, and the structure is simple and the cost is low.

[0036] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0038] Figure 1 A schematic diagram of a vacuum isolation feedthrough cavity structure provided in an embodiment of the present application;

[0039] Figure 2A schematic diagram of a transmission line sealing structure in a vacuum isolation feedthrough cavity structure provided in an embodiment of the present application;

[0040] Figure 3 A schematic flow chart of a method for manufacturing a transmission line sealing structure in a vacuum isolation feedthrough cavity structure provided in an embodiment of the present application.

[0041] Description of reference numerals:

[0042] 10. First vacuum chamber; 11. First vacuum chamber; 12. First end wall; 13. Transmission line fixing plate; 20. Transmission line; 30. Second vacuum chamber; 31. Second vacuum chamber; 32. Second end wall; 40. Vacuum pipe joint; 50. Transmission line sealing structure; 51. First filler; 52. Second filler; 60. Metal protection tube; 70. Transmission connection cover; 80. Transmission line connector. DETAILED DESCRIPTION

[0043] In order to make the technical solutions and beneficial effects of the present application more obvious and easy to understand, the following is a detailed description by listing specific embodiments. The drawings are not necessarily drawn to scale, and local features may be enlarged or reduced to more clearly show the details of the local features; unless otherwise defined, the technical and scientific terms used herein have the same meanings as those in the technical field to which the present application belongs.

[0044] In the description of the present application, terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "height", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicating orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of simplified description of the present application, and do not indicate that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and should not be understood as a limitation on the present application.

[0045] In this application, the terms "first" and "second" are used only for the purpose of clear description and should not be understood as the relative importance of the indicated features or the number of the indicated technical features. Therefore, the features defined as "first" and "second" can explicitly include at least one of the features. In the description of this application, "multiple" means at least two, such as two, three, etc.; "several" means at least one, such as one, two, three, etc., unless otherwise clearly and specifically defined.

[0046] In this application, unless otherwise clearly defined, the terms "install", "connect", "connect", "fix", "set", etc. should be understood in a broad sense. For example, "connection" 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 an indirect connection through an intermediate medium, or it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0047] In the present application, unless otherwise clearly defined, a first feature being “on”, “above”, “above”, “below”, “below”, “below” or “below” a second feature may mean that the first feature is in direct contact with the second feature, or the first feature and the second feature are in indirect contact with each other through an intermediate medium. Moreover, a first feature being “on”, “above” or “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the horizontal height of the first feature is higher than the horizontal height of the second feature. A first feature being “below”, “below” or “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the horizontal height of the first feature is lower than the horizontal height of the second feature.

[0048] In order to thoroughly understand the present application, detailed steps and detailed structures will be presented in the following description to illustrate the technical solution of the present application. The preferred embodiments of the present application are described in detail below, but in addition to these detailed descriptions, the present application may also have other implementation methods. Embodiment 1

[0049] The present application embodiment provides a vacuum isolation feedthrough cavity structure, which is applied to a Thomson scattering diagnostic system. The Thomson scattering diagnostic system includes a first vacuum cavity 10 and a transmission line 20 for transmitting data from the first vacuum cavity 10 to the outside. Figure 1 and Figure 2 , the vacuum isolation feedthrough cavity structure comprises:

[0050] A second vacuum chamber 30, one end of which in the first direction abuts against the first end wall 12 of the first vacuum chamber 10, and the other end of which in the first direction is sealed with a second end wall 32, so as to form a second vacuum chamber 31 for the transmission line 20 to pass through; the first direction is the direction in which the transmission line 20 passes out of the first vacuum chamber 10;

[0051] A vacuum pipe joint 40 is provided on any side wall of the second vacuum chamber 30, and the vacuum pipe joint 40 is used to connect the second vacuum chamber 31 to a vacuum forming mechanism or a vacuum detecting mechanism, so as to form the second vacuum chamber 31 by pumping air or to detect the vacuum degree of the second vacuum chamber 31;

[0052] The transmission line sealing structure 50 includes a first sealing structure and a second sealing structure, wherein the first sealing structure is disposed at the junction where the transmission line 20 passes through the first end wall 12, so that the transmission line 20 remains sealed when passing through the first end wall 12;

[0053] The second sealing structure is arranged at the junction where the transmission line 20 passes through the second end wall 32, so that the transmission line 20 remains sealed when passing through the second end wall 32; the transmission line sealing structure 50 includes a sealing filler, and the sealing filler is filled in the radial gap between the transmission line 20 and the end wall; the end wall includes the first end wall 12 and the second end wall 32.

[0054] It can be understood that one end of the second vacuum chamber 30 is in contact with the first end wall 12 of the first vacuum chamber 10, which can be considered as adding a vacuum chamber outside the first vacuum chamber 10 to form a two-stage vacuum chamber. In this way, the vacuum environment of the first vacuum chamber 11 can be more stable.

[0055] Specifically, the first vacuum chamber 10 and the second vacuum chamber 30 may be cylindrical in shape, and the first direction may be the axial direction of the first vacuum chamber 10 and the second vacuum chamber 30 .

[0056] It is understandable that the vacuum pipe joint 40 can be an interface for forming a vacuum or an interface for detecting the vacuum degree. For example, when the installation is just completed, the second vacuum chamber 30 is not a vacuum environment yet, and a vacuum needs to be formed by pumping air. After the second vacuum chamber 31 is formed, the vacuum degree of the second vacuum chamber 31 needs to be detected regularly or irregularly.

[0057] Specifically, the vacuum degree requirement of the second vacuum chamber 31 may refer to the vacuum degree requirement of the first vacuum chamber.

[0058] Specifically, the vacuum pipe joint 40 may be provided with a one-way valve to reduce leakage of external gas into the second vacuum chamber 31 .

[0059] It can be understood that the transmission line sealing structure 50 is provided at the end wall where the transmission line 20 passes through the first vacuum chamber 10 and at the end wall where the transmission line 20 passes through the second vacuum chamber 30, thereby forming a two-level seal.

[0060] The sealing filler can be solid or semi-fluid. Among them, the solid can be solidified from the fluid, such as potting glue, electric welding, etc.

[0061] In the vacuum isolation feedthrough cavity structure of the embodiment of the present application, a second vacuum cavity 30 is arranged at the outer end of the first vacuum cavity 10 through which the transmission line 20 passes, and the second vacuum cavity 30 forms a second vacuum cavity 31, and a transmission line sealing structure 50 is arranged at the end wall where the transmission line 20 passes through the first vacuum cavity 10 and the end wall where the transmission line 20 passes through the second vacuum cavity 30, and the transmission line sealing structure 50 includes a sealing filler, and the sealing filler is filled in the radial gap between the transmission line 20 and the end wall; since the two end walls through which the transmission line 20 passes are both provided with the transmission line sealing structure 50, a two-level seal is formed, and the second vacuum cavity 31 also protects the vacuum degree of the first vacuum cavity 11, so the sealing structure is reliable, simple in structure, and low in cost.

[0062] In some other embodiments of the present application, the sealing filler is formed after performing a welding process.

[0063] The sealing filler formed by welding is high in strength, more solid and has a long service life.

[0064] In some other embodiments of the present application, the transmission line 20 is an optical fiber, and the optical fiber jacket is provided with a metal protection tube 60; the transmission line sealing structure 50 includes:

[0065] A first filler 51, which is filled in the radial gap between the optical fiber and the metal protection tube 60 after the welding process;

[0066] The second filler 52 is filled in the radial gap between the metal protection tube 60 and the end wall after the welding process.

[0067] In this way, sealing fillers can be arranged in both radial gaps to comprehensively block possible leakage.

[0068] Furthermore, the axial length of the first filler 51 is greater than the axial length of the second filler 52. Since the optical fiber is relatively soft in the longitudinal direction, it is necessary to increase the axial length to improve the sealing reliability.

[0069] It is understandable that the metal protection tube 60 may not be provided, but the optical fiber may be directly inserted into the end wall. In this way, the sealing reliability can be improved by increasing the thickness of the first end wall 12 and the second end wall 32 .

[0070] Specifically, the metal protection tube 60 can be a nickel tube or a stainless steel tube, so that it has both certain strength and good corrosion resistance.

[0071] In some other embodiments of the present application, the first filler 51 is formed after a brazing process;

[0072] The soldering agent of brazing has stronger permeability, which is suitable for the characteristics that the radial gap between the optical fiber and the metal protection tube 60 is very small, but the axial length is relatively long. In addition, the welding temperature of brazing can also be more accurately controlled to avoid damaging the optical fiber. It can be understood that other similar welding methods that meet the above characteristics are also possible.

[0073] The second filler 52 is formed by performing any one of the following processes: gas shielded welding, plasma arc welding, electron beam welding and laser beam welding.

[0074] The characteristics of the process for forming the second filler 52 are mainly that the welding area can be precisely controlled and the heat is low, etc. It can be understood that other similar welding that meets the above characteristics is also possible.

[0075] In some other embodiments of the present application, the first sealing structure and the second sealing structure further include a metal coating (not shown in the figures) plated on the outer surface of the optical fiber.

[0076] That is, before the welding process of the optical fiber and the metal protection tube 60, a coating is plated on the surface of the optical fiber to increase the rigidity and smoothness of the optical fiber surface and improve the sealing effect.

[0077] In some other embodiments of the present application, the second vacuum chamber 30 includes a side wall, and the side wall and the first end wall 12 are integrally formed.

[0078] One-piece manufacturing can further increase the reliability of sealing.

[0079] In some other embodiments of the present application, the side wall and the second end wall 32 are sealed and fixed so that the second vacuum chamber 31 is sealed on all sides.

[0080] In this way, when the sealing condition of the second vacuum chamber 31 is formed, it is more convenient to assemble with the first vacuum chamber 10 and to set the transmission line sealing structure 50 .

[0081] In some other embodiments of the present application, the vacuum isolation feedthrough cavity structure further includes:

[0082] The transmission line fixing plate 13 is fixed to the inner wall of the first vacuum chamber 10 on all sides, and a conduit for the transmission line 20 to pass into the first vacuum chamber 10 is fixed in the middle, and a preset structure for limiting the position of the transmission line 20 is arranged in the conduit.

[0083] The transmission line fixing plate 13 can better fix the transmission line 20 and reduce damage to the transmission line 20. The preset structure can be an elastic wire clamp or the like.

[0084] Furthermore, the circumferential side of the transmission line fixing plate 13 can be sealed and connected to the inner cavity of the first vacuum chamber 10. In this way, a third vacuum chamber can be formed between the first vacuum chamber 11 and the second vacuum chamber 31, forming a three-level seal, which can further maintain the vacuum state of the first vacuum chamber 11, making the vacuum state of the first vacuum chamber 11 more stable and reliable.

[0085] In some other embodiments of the present application, the vacuum isolation feedthrough cavity structure further includes:

[0086] The transmission connection cover 70 has one end connected to the second end wall 32 and the other end provided with a transmission line connector 80 , and the transmission line connector 80 is used to connect the transmission line 20 to an external device.

[0087] Furthermore, the transmission connection cover 70 can be sealed to the second end wall 32, and the other end is also sealed to the outside. Specifically, the connection between the transmission line 20 and the transmission line connector 80 is sealed, and the connection between the transmission line connector 80 and the transmission connection cover 70 is sealed. In this way, a fourth vacuum chamber can be added outside the second vacuum chamber 31 to form a four-level seal. The vacuum state of the second vacuum chamber 31 can be further maintained, thereby making the vacuum state of the first vacuum chamber 11 more stable and reliable. Embodiment 2

[0088] This embodiment provides a Thomson scattering diagnostic system, including:

[0089] The first vacuum chamber 10 has a first vacuum chamber 11;

[0090] A transmission line 20, used for transmitting data from the first vacuum chamber 11 to the outside;

[0091] The vacuum isolation feedthrough cavity structure described in the first embodiment.

[0092] As described above, the first vacuum chamber 10 may be in the shape of a cylinder, and the transmission line 20 passes through the axial direction of the first vacuum chamber 10 and extends along the axial direction.

[0093] The second vacuum chamber 30 in the vacuum isolation feedthrough chamber structure described in the first embodiment abuts against the first vacuum chamber 10 in the axial direction of the first vacuum chamber 10 . The second vacuum chamber 30 also has a cylindrical shape, which facilitates docking with the first vacuum chamber 10 .

[0094] In the Thomson scattering diagnostic system of the embodiment of the present application, a second vacuum chamber 30 is arranged at the outer end of the first vacuum chamber 10 through which the transmission line 20 passes, and the second vacuum chamber 30 forms a second vacuum chamber 31. A transmission line sealing structure 50 is arranged at the end wall where the transmission line 20 passes through the first vacuum chamber 10 and the end wall where the transmission line 20 passes through the second vacuum chamber 30. The transmission line sealing structure 50 includes a sealing filler, and the sealing filler is filled in the radial gap between the transmission line 20 and the end wall. Since the two end walls through which the transmission line 20 passes are both provided with the transmission line sealing structure 50, a two-level seal is formed, and the second vacuum chamber 31 also protects the vacuum degree of the first vacuum chamber 11, so the sealing structure is reliable, simple in structure, and low in cost. Embodiment 3

[0095] This embodiment provides a magnetic confinement nuclear fusion experimental device, including the Thomson scattering diagnostic system described in the second embodiment.

[0096] In the magnetic confinement nuclear fusion experimental equipment of the embodiment of the present application, a second vacuum chamber 30 is arranged at the outer end of the first vacuum chamber 10 through which the transmission line 20 passes, and the second vacuum chamber 30 forms a second vacuum chamber 31. A transmission line sealing structure 50 is arranged at the end wall where the transmission line 20 passes through the first vacuum chamber 10 and the end wall where the transmission line 20 passes through the second vacuum chamber 30. The transmission line sealing structure 50 includes a sealing filler, and the sealing filler is filled in the radial gap between the transmission line 20 and the end wall. Since the two end walls through which the transmission line 20 passes are both provided with the transmission line sealing structure 50, a two-level seal is formed, and the second vacuum chamber 31 also protects the vacuum degree of the first vacuum chamber 11, so the sealing structure is reliable, simple in structure, and low in cost. Embodiment 4

[0097] This embodiment provides a method for manufacturing a transmission line sealing structure in a vacuum isolation feedthrough cavity structure. Figure 3 , the method comprising:

[0098] Step 801: sealing the joint where the transmission line 20 passes through the end wall to form a transmission line sealing structure 50; wherein:

[0099] A brazing process is performed in the radial gap between the transmission line 20 and the metal protection tube 60, and the welding temperature is lower than or equal to 600 degrees Celsius.

[0100] The control of welding temperature is to reduce the damage of high temperature to optical fiber. It can be understood that 600 degrees Celsius is a conservative control target. In this way, even if there is a deviation in temperature control during the actual manufacturing process, so that the actual welding temperature is slightly higher than 600 degrees Celsius, such as 650 degrees Celsius or 700 degrees Celsius, the optical fiber will not be damaged.

[0101] Specifically, the control of welding temperature can be achieved by controlling welding power.

[0102] In other embodiments of the present application, continue to refer to Figure 3 , the method further comprises:

[0103] Step 802: After the transmission line sealing structure 50 is formed, a sealing performance test is performed, and the sealing performance test includes:

[0104] The vacuum isolation feedthrough cavity structure is subjected to at least three hot and cold cycle processes, and a vacuum leak rate test is performed when the temperature during each hot and cold cycle reaches a preset high temperature; the preset high temperature is 240 degrees Celsius.

[0105] It is understandable that the hot and cold cycles may affect the state of the sealing filler, which may lead to changes in the sealing performance. Therefore, it is necessary to test the sealing performance through hot and cold cycles.

[0106] Specifically, the vacuum leak rate requirement may be 1×10 -10 Pa·m 3 / s. As mentioned above, 1×10 -10 Pa·m 3 / s is a conservative control target. Similarly, 240 degrees Celsius is also a conservative control target.

[0107] The manufacturing method of the transmission line sealing structure in the vacuum isolation feedthrough cavity structure of the embodiment of the present application can obtain a stable and reliable sealing structure and reduce the damage to the optical fiber by controlling the welding temperature and performing sealing performance testing after the transmission line sealing structure 50 is formed.

[0108] It should be understood that the above embodiments are exemplary and are not intended to include all possible implementations included in the claims. Various modifications and changes may be made on the basis of the above embodiments without departing from the scope disclosed in the present application. Similarly, the various technical features of the above embodiments may be arbitrarily combined to form other embodiments of the present application that may not be explicitly described. Therefore, the above embodiments only express several implementations of the present application and do not limit the scope of protection of the patent of this application.

Claims

1. A vacuum-insulated feedthrough cavity structure, applied to a Thomson scattering diagnostic system, wherein the Thomson scattering diagnostic system comprises a first vacuum cavity and a transmission line for transmitting data from the first vacuum cavity to the outside, characterized in that: include: A second vacuum cavity, one end of which in the first direction abuts against the first end wall of the first vacuum cavity, and the other end of which in the first direction is sealed with a second end wall, so as to form a second vacuum cavity for the transmission line to pass through; the first direction is the direction in which the transmission line passes out of the first vacuum cavity; a vacuum pipe joint, arranged on any side wall of the second vacuum cavity, and used to connect the second vacuum cavity to a vacuum forming mechanism or a vacuum detecting mechanism, so as to form the second vacuum cavity by pumping air or to detect the vacuum degree of the second vacuum cavity; A transmission line sealing structure, comprising a first sealing structure and a second sealing structure, wherein the first sealing structure is arranged at a junction where the transmission line passes through the first end wall, so that the transmission line remains sealed at the junction where the transmission line passes through the first end wall; The second sealing structure is arranged at the junction where the transmission line passes through the second end wall, so that the transmission line remains sealed when passing through the second end wall; the transmission line sealing structure includes a sealing filler, and the sealing filler is filled in the radial gap between the transmission line and the end wall; the end wall includes the first end wall and the second end wall.

2. The vacuum isolation feedthrough cavity structure according to claim 1, characterized in that: The sealing filler is formed after a welding process is performed.

3. The vacuum isolation feedthrough cavity structure according to claim 2, characterized in that: The transmission line is an optical fiber, and the optical fiber jacket is provided with a metal protection tube; the transmission line sealing structure includes: A first filler, which is filled between the radial gap between the optical fiber and the metal protection tube after a welding process is performed; The second filler is filled in the radial gap between the metal protection tube and the end wall after the welding process is performed.

4. The vacuum isolation feedthrough cavity structure according to claim 3, characterized in that: The first filler is formed after a brazing process; The second filler is formed after performing any one of the following processes: gas shielded welding, plasma arc welding, electron beam welding and laser beam welding.

5. The vacuum isolation feedthrough cavity structure according to claim 4, characterized in that: The first sealing structure and the second sealing structure further include a metal coating plated on the outer surface of the optical fiber.

6. The vacuum isolation feedthrough cavity structure according to claim 1, characterized in that: The second vacuum chamber includes a side wall, and the side wall is integrally formed with the first end wall.

7. The vacuum isolation feedthrough cavity structure according to claim 6, characterized in that: The side wall and the second end wall are sealed and fixed to make the second vacuum chamber sealed all around.

8. The vacuum isolation feedthrough cavity structure according to claim 1, characterized in that: The vacuum isolation feedthrough cavity structure further comprises: The transmission line fixing plate is fixed on the inner wall of the first vacuum chamber on all sides, and a conduit for the transmission line to pass into the first vacuum chamber is fixed in the middle, and a preset structure for limiting the position of the transmission line is arranged in the conduit.

9. A Thomson scattering diagnostic system, characterized in that: include: A first vacuum chamber having a first vacuum chamber; A transmission line, used for transmitting data from the first vacuum chamber to the outside; The vacuum isolation feedthrough cavity structure according to any one of claims 1 to 8.

10. A magnetic confinement nuclear fusion experimental device, characterized in that: A Thomson scattering diagnostic system comprising the Thomson scattering diagnostic system of claim 9.

11. A method for manufacturing a transmission line sealing structure in a vacuum isolation feedthrough cavity structure according to any one of claims 1 to 8, characterized in that: The method comprises: The joint where the transmission line passes through the end wall is sealed to form a transmission line sealing structure; wherein: Brazing is performed in the radial gap between the transmission line and the metal protection tube, and the welding temperature is lower than or equal to 600 degrees Celsius.

12. The method for manufacturing a transmission line sealing structure in a vacuum isolation feedthrough cavity structure according to claim 11, characterized in that: The method further comprises: After the transmission line sealing structure is formed, a sealing performance test is performed, and the sealing performance test includes: The vacuum isolation feedthrough cavity structure is subjected to at least three hot and cold cycle processes, and a vacuum leak rate test is performed when the temperature during each hot and cold cycle reaches a preset high temperature; the preset high temperature is 240 degrees Celsius.

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