A large flux imaging system applied to flexible bending of a nuclear fusion device

Abstract

The application relates to the technical field of magnetic confinement fusion plasma, and particularly discloses a large-flux imaging system applied to a flexible bending nuclear fusion device, which comprises, from an object side to an image side, a front large-light-flux imaging objective lens, an image transmission fiber bundle, a relay objective lens group and a camera which are sequentially connected; the relay objective lens group comprises two groups of large-aperture lenses which are symmetrically arranged along an optical axis; and the first lenses of the two groups of large-aperture lenses are arranged on the side close to each other. The application is the largest light flux imaging light path based on the image transmission fiber bundle technology in an international magnetic confinement fusion device; and can effectively realize the measurement of fast physical phenomena in high-temperature plasma.

Description

Technical Field

[0001] This invention relates to the field of magnetic confinement fusion plasma technology, and more specifically, to a high-throughput imaging system for flexible bending in nuclear fusion devices. Background Technology

[0002] In the field of magnetic confinement fusion plasma, monitoring the activity of high-temperature plasma is essential for the safe operation of the device. Visible light imaging systems can provide important information on plasma-wall interactions (PWI), such as plasma configuration and boundary changes, hotspot distribution, asymmetric distribution of particle recycling, wall corrosion rate and particle flux (using filters), etc. Therefore, it is a very important diagnostic tool for high-temperature plasma.

[0003] Because fusion plasma possesses strong magnetic fields and intense radiation (neutrons, gamma rays, etc.), to avoid interference from plasma radiation and magnetic field changes on cameras, precision electronic devices such as cameras should be kept away from the facility and outside the radiation shielding wall. Furthermore, due to the operation of many large devices, the space surrounding nuclear fusion facilities is often complex. One imaging scheme uses long-range lenses and mirrors to form an image, but this has extremely stringent spatial requirements; another imaging scheme utilizes a bundle of image-transmitting optical fibers, which can flexibly guide the light emitted by the high-temperature plasma to a distant location.

[0004] Current fiber optic imaging schemes primarily utilize dual telecentric objectives and macro objectives as relay lenses between the fiber optic bundle and the camera. Their numerical aperture is rarely greater than 0.25, thus limiting the overall light throughput of the imaging system. Under these light throughput conditions, measuring fast physical phenomena in high-temperature plasmas (such as plasma large-scale disruption evolution and edge-localized mode bursts) is difficult. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a high-throughput imaging system that can be flexibly bent in nuclear fusion devices. The numerical aperture of the system can reach 0.6, which is the imaging optical path with the largest light throughput based on image transmission fiber bundle technology in international magnetic confinement fusion devices; it can effectively realize the measurement of fast physical phenomena in high-temperature plasma.

[0006] The solution adopted by this invention to solve the technical problem is: A high-throughput imaging system for flexible bending in nuclear fusion devices includes a front-end high-throughput imaging objective, an image transmission fiber bundle, a relay objective group, and a camera connected sequentially from the object side to the image side. The relay objective lens group includes two sets of large-aperture lenses symmetrically arranged along the optical axis. The first lens elements of the two sets of large-aperture lenses are positioned close to each other on one side.

[0007] In some possible implementations, the front-end high-throughput imaging objective has an F-number of 0.8; the relay objective group has an F-number of 0.8; the large-aperture lens has an F-number of 0.8; and the object plane of both large-aperture lenses is set to infinity.

[0008] In some possible implementations, the numerical aperture of the high-throughput imaging system is 0.6.

[0009] In some possible implementations, the image-side numerical aperture of the front-end high-throughput imaging objective is 0.625; the numerical aperture of the image transmission fiber bundle is 0.6; and the image-side numerical aperture of the relay objective group is 0.625.

[0010] In some possible implementations, the large aperture lens includes a cemented doublet convex lens A, a single convex lens A, a cemented doublet convex lens B, a single convex lens B, a cemented doublet concave lens A, a single concave lens A, a single convex lens C, and a single convex lens D arranged sequentially; the focal length of the large aperture lens is 25mm.

[0011] In some possible implementations, the single convex lens D of the two sets of large aperture lenses is positioned close to one side.

[0012] In some possible implementations, the front-end high-throughput imaging objective includes a cemented doublet first, a single convex lens first, a cemented doublet second, a cemented doublet third, a single convex lens second, a cemented doublet fourth, and a single convex lens third arranged sequentially along the optical axis, and an aperture stop disposed between the cemented doublet second and the cemented doublet third, wherein the focal length of the front-end high-throughput imaging objective is 21.75 mm.

[0013] In some possible implementations, the image transmission fiber bundle consists of multiple fiber filaments arranged in a quadrilateral, hexagonal, or circular pattern.

[0014] In some possible implementations, the end face area of ​​the image transmission fiber bundle is 16 × 16 mm. 2 The core diameter of the optical fiber is 16μm.

[0015] In some possible implementations, the image plane of the front-end high-throughput imaging objective coincides with the input end face of the image transmission fiber bundle, the output end face of the image transmission fiber bundle coincides with the object plane of the relay objective group, and the image plane of the relay objective group coincides with the target plane of the camera.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention, through the setup of a front-end high-throughput imaging objective and a relay objective group, enables the numerical aperture of the entire system to reach 0.6, making it the imaging optical path with the highest light throughput based on image transmission fiber bundle technology in international magnetic confinement fusion devices; thereby effectively realizing the measurement of fast physical phenomena in high-temperature plasma (such as plasma large-scale fracture evolution and edge local mode bursts). This invention, through the arrangement of the image transmission fiber bundle, flexibly bends to guide the light emission of high-temperature plasma to a distant end, thus enabling the invention to become a flexible and high-throughput imaging system. At the same time, the image transmission fiber bundle can be used in harsh environments such as high magnetic fields, strong radiation, and high humidity. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the structure of the high-throughput imaging objective lens at the front end in this invention; Figure 3 This is a schematic diagram of the structure of the large aperture lens in this invention; in: 1. High-throughput imaging objective lens at the front end; 11. Cemented doublet lens one; 12. Single convex lens one; 13. Cemented doublet lens two; 14. Cemented doublet lens three; 15. Single convex lens two; 16. Cemented doublet lens four; 17. Single convex lens three; 2. Image transmission fiber bundle; 3. Relay objective lens group; 30. Large aperture lens; 31. Cemented doublet convex lens A; 32. Single convex lens A; 33. Cemented doublet convex lens B; 34. Single convex lens B; 35. Cemented doublet concave lens A; 36. Single concave lens A; 37. Single convex lens C; 38. Single convex lens D; 4. Camera. Detailed Implementation

[0018] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., 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 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. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms "a" or "one," etc., do not indicate a quantity limitation, but rather indicate the presence of at least one.

[0019] In this invention, "and / or" describes the relationship between associated objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0020] In the description of the embodiments of the present invention, unless otherwise stated, "a plurality of" means two or more. For example, a plurality of positioning posts means two or more positioning posts. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0021] The present invention will now be described in detail.

[0022] like Figures 1-3 As shown: A high-throughput imaging system for flexible bending in nuclear fusion devices includes a front-end high-throughput imaging objective lens 1, an image transmission fiber bundle 2, a relay objective lens group 3, and a camera 4 connected sequentially from the object side to the image side. The front-end high-throughput imaging objective lens 1 is used to focus and image the fusion plasma. The image formed enters at the input end face of the image transmission fiber bundle 2 and is transmitted to the output end face of the image transmission fiber bundle 2. The image at the output end face of the image transmission fiber bundle 2 is imaged by the relay objective lens group 3 onto the target surface of the camera 4, and finally captured by the camera 4. The relay objective lens group 3 includes two sets of large-aperture lenses 30 symmetrically arranged along the optical axis; the first lens of the two sets of large-aperture lenses 30 is arranged close to each other, that is, the two sets of identical large-aperture lenses are placed "head to head". By adopting this arrangement, the front-end large-throughput imaging objective lens 1, the image transmission fiber bundle 2, the relay objective lens group 3 and the camera 4 can meet the requirements of large-throughput imaging.

[0023] The image plane of the front-end high-throughput imaging objective 1 coincides with the input end face of the image transmission fiber bundle 2, the output end face of the image transmission fiber bundle 2 coincides with the object plane of the relay objective group 3, and the image plane of the relay objective group 3 coincides with the target plane of the camera 4.

[0024] In some possible implementations, the front-end high-throughput imaging objective 1 has an F-number of 0.8, the relay objective group 3 has an F-number of 0.8, and the large-aperture lens 30 has an F-number of 0.8; the object plane of both large-aperture lenses 30 is set to infinity. The front-end high-throughput imaging objective 1 has an image-side numerical aperture of 0.625; the image transmission fiber bundle 2 has a numerical aperture of 0.6; and the relay objective group 3 has an image-side numerical aperture of 0.625. This results in a numerical aperture of 0.6 for the high-throughput imaging system, making it the imaging optical path with the highest light throughput based on the image transmission fiber bundle 2 technology in international magnetic confinement fusion devices.

[0025] In some possible implementations, the large-aperture lens 30 comprises eleven lens elements in eight groups. Specifically, the eight groups include, sequentially arranged, a cemented doublet convex lens A31, a single convex lens A32, a cemented doublet convex lens B33, a single convex lens B34, a cemented doublet concave lens A35, a single concave lens A36, a single convex lens C37, and a single convex lens D38. The spacing between the eight lens groups is adjusted and fixed by spacers inside the lens barrel. The first lens element described in this invention, the first lens element on the object-side side of the large-aperture lens 30 during conventional use, is the single convex lens D38. The single convex lenses D38 of the two large-aperture lens groups 30 are positioned close to each other. The focal length of the large-aperture lens 30 is 25mm.

[0026] Specifically, when the two sets of large aperture lenses 30 are used together as relay objective lens group 3, the single convex lens D38 of the two sets of large aperture lenses 30 are set on the side close to each other; since the light emitted from different image heights of the image plane of the large aperture lens 30 near the image transmission fiber bundle 2 is parallel light on the object plane of the large aperture lens 30, these parallel lights are collected by another set of large aperture lenses 30 (on the side close to the camera 4) and imaged at the image plane of the large aperture lens 30 on the side close to the camera 4. Since the image plane of the large aperture lens 30 near the camera 4 coincides with the target plane of the camera 4, the image plane of the large aperture lens 30 near the image transmission fiber bundle 2 and the image plane of the large aperture lens 30 near the camera 4 form a pair of conjugate planes.

[0027] In some possible implementations, the front-end high-throughput imaging objective 1 includes seven groups of eleven lenses and an aperture stop; specifically, the seven groups are arranged sequentially along the optical axis: a cemented doublet first lens 11, a single convex lens first lens 12, a cemented doublet second lens 13, a cemented doublet third lens 14, a single convex lens second lens 15, a cemented doublet fourth lens 16, and a single convex lens third lens 17, and an aperture stop disposed between the cemented doublet second lens 13 and the cemented doublet third lens 14; the focal length of the front-end high-throughput imaging objective 1 is 21.75 mm; Furthermore, the seven lens groups and the aperture stop are connected sequentially inside the lens barrel, and the spacing between the seven lens groups is adjusted and fixed by the spacers inside the lens barrel.

[0028] Furthermore, the second convex lens 15 is an aspherical lens with a large curvature surface; the third convex lens 17 is a convex lens with a double aspherical surface.

[0029] In some possible implementations, the image transmission fiber bundle 2 is composed of multiple fiber filaments arranged in a quadrilateral, hexagonal, or circular pattern.

[0030] In some possible implementations, the end face area of ​​the image transmission fiber bundle 2 is 16 × 16 mm. 2The core diameter of the optical fiber is 16μm.

[0031] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. A high-throughput imaging system for flexible bending in nuclear fusion devices, characterized in that, It includes a front-end high-throughput imaging objective lens, an image transmission fiber bundle, a relay objective lens group, and a camera, which are connected sequentially from the object side to the image side; The relay objective lens group includes two sets of large-aperture lenses with a focal length of 25mm, symmetrically arranged along the optical axis. The large aperture lens comprises eleven elements in eight groups. The eight groups include, in sequence, a cemented doublet convex lens A, a single convex lens A, a cemented doublet convex lens B, a single convex lens B, a cemented doublet concave lens A, a single concave lens A, a single convex lens C, and a single convex lens D. The single convex lens D of the two sets of large aperture lenses is set as the first lens element on a side close to each other. The front-end high-throughput imaging objective has an F-number of 0.8; the relay objective group has an F-number of 0.8; the large-aperture lens has an F-number of 0.8; and the object plane of both large-aperture lenses is set to infinity.

2. The high-throughput imaging system for flexible bending in a nuclear fusion device according to claim 1, characterized in that, The numerical aperture of the high-throughput imaging system is 0.

6.

3. A high-throughput imaging system for flexible bending in a nuclear fusion device according to claim 2, characterized in that, The front-end high-throughput imaging objective has an image-side numerical aperture of 0.625; the image transmission fiber bundle has a numerical aperture of 0.6; and the relay objective group has an image-side numerical aperture of 0.

625.

4. The high-throughput imaging system for flexible bending in a nuclear fusion device according to claim 1, characterized in that, The front-end high-throughput imaging objective includes a cemented doublet lens 1, a single convex lens 1, a cemented doublet lens 2, a cemented doublet lens 3, a single convex lens 4, and a single convex lens 5 arranged sequentially along the optical axis, and an aperture stop disposed between the cemented doublet lens 2 and the cemented doublet lens 3. The focal length of the front-end high-throughput imaging objective is 21.75 mm.

5. A high-throughput imaging system for flexible bending in a nuclear fusion device according to claim 1, characterized in that, The image transmission fiber bundle consists of multiple fiber filaments arranged in quadrilateral, hexagonal, or circular patterns.

6. A high-throughput imaging system for flexible bending in a nuclear fusion device according to claim 5, characterized in that, The end face area of ​​the image transmission fiber bundle is 16×16 mm. 2 The core diameter of the optical fiber is 16μm.

7. A high-throughput imaging system for flexible bending in a nuclear fusion device according to any one of claims 1-6, characterized in that, The image plane of the high-throughput imaging objective lens at the front end coincides with the input end face of the image transmission fiber bundle, the output end face of the image transmission fiber bundle coincides with the object plane of the relay objective lens group, and the image plane of the relay objective lens group coincides with the target plane of the camera.

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