A plasma vacuum plume observation device

Abstract

This invention belongs to the field of plume observation, specifically relating to a plasma vacuum plume observation device. Located within a vacuum chamber, it includes a periscope-style pipe assembly composed of multiple sequentially connected tubes, with reflectors positioned between adjacent tubes to alter the optical path. The first end of the periscope-style pipe assembly faces the observation window of the vacuum chamber, and the second end is positioned downstream of the nozzle of a nozzle, so that light rays from the plasma plume incident from the nozzle's nozzle and entering from the second end can have their path altered by the reflectors before exiting from the first end to the observation window. Based on the periscope-style pipe structure, this invention achieves non-contact, optimally positioned plume observation within a vacuum chamber.

Description

Technical Field

[0001] This invention belongs to the field of plume observation, specifically relating to a plasma vacuum plume observation device. Background Technology

[0002] Observing plasma plumes within a vacuum chamber is a crucial method for evaluating the performance of space propulsion devices and studying plasma behavior. Currently, the mainstream approach involves installing one or more fixed optical observation windows on the chamber walls. High-speed cameras or spectrometers positioned outside the chamber are used to image or perform spectral analysis of the light radiation emitted by the plume through these windows. Measurements of fundamental plasma parameters typically rely on a robotic arm that can extend into the chamber, carrying contact sensors such as Langmuir probes, which are positioned to collect data from specific areas of the plume.

[0003] However, the aforementioned existing technical solutions have significant limitations. First, the observation perspective is rigid: the fixed position of the observation window determines that the angle of the observation line cannot be changed, making it difficult to obtain three-dimensional morphological information of the plume from the side or at a specific angle, resulting in partial spatial data, and a single perspective cannot achieve three-dimensional reconstruction of the plume. Second, measurement methods interfere with each other: the introduction of contact probes can disturb the plasma flow field under test, and their support mechanisms may also block the optical observation path, making it difficult for optical and electrical measurements to be coordinated under the same spatiotemporal reference. Third, the system flexibility is severely lacking: when it is necessary to study the spatial distribution or time evolution of plume parameters, existing devices cannot achieve rapid, accurate, and programmed movement of the observation point along the plume axis or around its circumference, resulting in low measurement efficiency. Finally, the equipment faces safety and compatibility challenges: precision optical components directly exposed to the plume environment pose a risk of contamination and damage, while complex motion mechanisms cannot simultaneously meet the stringent requirements of large-scale movement, internal optical path transmission, and ultra-high vacuum sealing.

[0004] Therefore, given the current limitations of observation angles within vacuum chambers and the difficulty in conducting comprehensive and flexible diagnostics of plasma plumes, a novel integrated observation system solution is urgently needed. This solution must overcome the limitations of fixed viewing angles without directly interfering with the plume, enabling remote, precise, and flexible adjustment of the observation position and angle. It should also organically integrate non-contact optical observation with contact probe diagnostic functions, thereby providing reliable technical support for comprehensive, accurate, and in-situ measurements of plasma plumes. Summary of the Invention

[0005] The technical problem to be solved by this invention is to provide a plasma vacuum plume observation device. Based on a periscope-style pipe structure, it enables non-contact, optimally positioned plume observation within a vacuum chamber.

[0006] This invention provides a plasma vacuum plume observation device, disposed in a vacuum chamber, comprising: The periscope pipe assembly consists of multiple tubes connected in sequence, with mirrors between adjacent tubes for changing the optical path; The first end of the periscope-type pipe assembly faces the observation window of the vacuum chamber, and the second end is configured to face downstream of the nozzle, so that light rays from the plasma plume from the nozzle, incident from the second end, can be deflected by the reflector and then emitted from the first end to the observation window. Furthermore, the second end is capable of performing at least one of the following movements: circumferential rotation about the nozzle axis and axial translation along the nozzle axis.

[0007] Furthermore, the periscope-style pipe assembly includes multiple pipes connected in sequence, specifically including: The rotating base section has its axis coaxial with the nozzle axis of the nozzle. The first fixed section of the rotating base section is connected to the vacuum chamber, and its rotating section can rotate around its own axis. A rotary drive mechanism is used to drive the rotary segment to rotate; The first vertical segment is connected at one end to the rotating segment and is connected to the rotating base segment at a 90° angle. A parallel segment is connected to the other end of the first vertical segment and is configured to be parallel to the nozzle axis of the nozzle. The second vertical section, connected to the parallel section, has its outlet forming the second end of the periscope-type pipe assembly and is spaced apart from the nozzle axis.

[0008] Furthermore, the first fixed section and the rotating section of the rotating base segment are hollow tubes that are rotatably connected to each other; The rotary drive mechanism includes an external gear disposed on the outer wall of the rotary section and a drive assembly. The drive assembly includes a first rotary drive member and a drive gear driven thereby. The drive gear meshes with the external gear to drive the rotary section to rotate around its axis.

[0009] Furthermore, the other end of the first fixed section of the rotating base segment extends toward the observation window of the vacuum chamber via one or more tubes.

[0010] Furthermore, the parallel segment includes a second fixed segment and a telescopic segment that is slidably connected to the second fixed segment, wherein both the second fixed segment and the telescopic segment are hollow tubes; It also includes a telescopic drive mechanism for driving the telescopic segment to telescopically move relative to the second fixed segment.

[0011] Furthermore, the telescopic drive mechanism includes a rack disposed on the telescopic section and a telescopic drive assembly disposed on the second fixed section; The telescopic drive assembly includes a second rotary drive member and a drive gear disposed on the output shaft of the second rotary drive member; The drive gear meshes with the rack to drive the telescopic section to translate along its axial direction.

[0012] Furthermore, a sensor mounting bracket is provided on the outer wall of the second end of the periscope pipe assembly for mounting a probe sensor.

[0013] Furthermore, two adjacent tubes are connected by a tube connector, the two ends of which are angled connections for connecting the tubes, and a reflector for changing the optical path is provided in the middle.

[0014] Furthermore, both the first and second ends of the periscope-type pipe assembly are funnel-shaped structures that gradually expand outwards toward their openings.

[0015] The beneficial effects of this invention are that the plasma vacuum plume observation device provided by this invention, through its periscope-style pipe assembly design, successfully solves the technical problems of traditional observation methods, such as the probe's susceptibility to plume contamination and flow field interference, as well as the fixed observation angle and difficulty in fully capturing the three-dimensional morphology of the plume. This device enables flexible, in-situ, and non-invasive optical observation of plasma plumes within a vacuum chamber. It protects delicate optical sensing elements while acquiring observation data from multiple angles and locations, providing stable and reliable hardware support for in-depth research on the plume's diffusion characteristics, parameter distribution, and its interaction with the vacuum environment. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is the front view of the present invention; Figure 3 for Figure 2 Sectional view along line AA; Figure 4 This is a schematic diagram of the plasma vacuum plume observation device in this invention; Figure 5 This is a front view of the plasma vacuum plume observation device in this invention; Figure 6 for Figure 5 Sectional view along the BB direction; Figure 7 for Figure 5 Sectional view along the CC direction.

[0017] In the figure, 1-Plasma vacuum plume observation device; 11-Periscope pipe assembly; 111-Pipe body; 111a-Rotating base section; 111a1-First fixed section; 111a2-Rotating section; 111b-First vertical section; 111c-Parallel section; 111c1-Second fixed section; 111c2-Telescopic section; 111d-Second vertical section; 112-Pipe body connector; 12-Reflector; 13-Rotary drive mechanism; 131-External gear; 132-First rotary drive component; 133-Drive gear; 14-Telescopic drive mechanism; 141-Rack; 142-Second rotary drive component; 143-Drive gear; 15-Sensor mounting bracket; 2-Vacuum chamber; 21-Observation window; 3-Nozzle; 31-Nozzle. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0019] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0020] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0021] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection, an electrical connection, a physical connection, or a wireless communication connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two elements or the interaction between two elements, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0022] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0023] like Figures 1-7 As shown, the present invention provides a plasma vacuum plume observation device 1, which is installed inside a vacuum chamber 2, and includes: The periscope-type pipe assembly 11 is composed of multiple tubes 111 connected in sequence. It is used to construct an internal optical path channel in the vacuum chamber 2. A reflector 12 is set between adjacent tubes 111 to change the optical path. Through the refraction of the reflector 12, the observation optical path is turned multiple times to form a periscope-like structure, thereby bypassing the obstruction of other equipment or structures in the vacuum chamber 2 and flexibly extending the observation point to the target area. The first end of the periscope-type pipe assembly 11 faces the observation window 21 of the vacuum chamber 2, so that the plume optical signal transmitted through the internal optical path can be finally output to the outside of the vacuum chamber 2, which is convenient for docking with external observation and recording equipment such as high-speed cameras and spectrometers to achieve non-contact remote observation. The second end is set to face downstream of the nozzle 31 of the nozzle 3. The second end faces the core diffusion area of ​​the plasma plume, ensuring that the most representative plume morphology and radiation information can be collected, so that the light from the plasma plume from the nozzle 31 of the nozzle 3, which enters from the second end, can change its path through the reflector 12 and then be emitted from the first end to the observation window 21. The plasma vacuum plume observation device 1 provided by this invention, through the design of the periscope-type pipe assembly 11, successfully solves the technical problems of traditional observation methods, such as the probe being easily contaminated by the plume, interference with the flow field, and the fixed observation angle making it difficult to fully capture the three-dimensional morphology of the plume. This device enables flexible, in-situ, and non-invasive optical observation of the plasma plume within the vacuum chamber 2. It protects the delicate optical sensing elements while obtaining observation data from multiple angles and locations, providing stable and reliable hardware support for in-depth research on the plume's diffusion characteristics, parameter distribution, and its interaction with the vacuum environment.

[0024] In one embodiment, the second end can perform at least one of the following movements: The observation point can be rotated circumferentially around the nozzle 31 axis of the nozzle 3, so that it can scan the plume 360 ​​degrees, thereby realizing the all-round acquisition of the asymmetry of the plume cross-section with different angles, brightness and spectral distribution, and providing multi-view data for three-dimensional reconstruction. And by axially translating along the nozzle 31 axis of the nozzle 3, the observation point can be moved along the direction of plume diffusion, thereby systematically studying the evolution of plume parameters (such as temperature, density, and chemical composition) with axial distance and obtaining their spatial distribution and variation characteristics.

[0025] In this embodiment, by granting the second end degrees of freedom to rotate around an axis and move axially, the fixed observation point is upgraded to a dynamic observation point that can be flexibly positioned in both the axial and circumferential directions. This not only greatly expands the spatial range of data that can be acquired in a single experiment, but more importantly, it enables active and precise exploration of the spatial structure of the plasma plume, overcoming the inherent limitations of limited spatial information from traditional fixed observation windows or single probes. This provides a key technical means for accurately revealing the dynamic diffusion process and spatial inhomogeneity of the plume.

[0026] In one embodiment, the periscope-style pipe assembly 11 includes a plurality of sequentially connected pipe bodies 111, specifically including: The rotating base section 111a has its axis coaxial with the nozzle 31 axis of the nozzle 3. The rotating base section 111a establishes a reference axis that is completely consistent with the main axis of the plume diffusion for the rotational movement of the entire observation arm, ensuring that the trajectory of the rotational scan accurately surrounds the core area of ​​the plume being measured. The first fixed section 111a1 of the rotating base section 111a is connected to the vacuum chamber 2, and its rotating section 111a2 can rotate around its own axis. Rotary drive mechanism 13 is used to drive the rotating segment 111a2 to rotate; The first vertical segment 111b is connected at one end to the rotating segment 111a2 and is connected to the rotating base segment 111a at a 90° angle. Parallel segment 111c is connected to the other end of the first vertical segment 111b and is configured to be parallel to the axis of the nozzle 31 of the nozzle 3. The second vertical segment 111d is connected to the parallel segment 111c, and its outlet forms the second end of the periscope pipe assembly 11, and is spaced apart from the axis of the nozzle 31 of the nozzle 3.

[0027] This embodiment, by adding a first vertical segment 111b, a parallel segment 111c, and a second vertical segment 111d that are coaxially rotating with the nozzle 31 of the nozzle 3, to the radial and axial segments 111a, not only achieves a large-scale rotational scanning of the observation end in terms of structure, but more importantly, by strictly constraining the geometric angle (parallel segment 111c is parallel to the axis of the nozzle 31), it ensures the consistency of the observation angle and distance throughout the scanning process. This makes the data collected from different angles highly comparable and accurate, laying a solid hardware foundation for subsequent quantitative analysis and three-dimensional inversion.

[0028] In one embodiment, the first fixed section 111a1 and the rotating section 111a2 of the rotating base section 111a are hollow tubes that are rotatably connected to each other. This structural design ensures that the two can rotate relative to each other while ensuring the continuity of the optical path channel, so as to achieve the motion function without affecting the internal optical transmission. The rotary drive mechanism 13 includes an external gear 131 disposed on the outer wall of the rotating section 111a2 and a drive assembly. The drive assembly includes a first rotary drive member 132 and a drive gear 133 driven by it. The drive gear 133 meshes with the external gear 131 to drive the rotating section 111a2 to rotate around its axis. The gear meshing transmission method has the advantages of precise transmission, smoothness, and large torque, realizing the precise start, stop, and positioning of the observation arm.

[0029] In one embodiment, the other end of the first fixed segment 111a1 of the rotating base segment 111a extends toward the observation window 21 of the vacuum chamber 2 via one or more tubes 111. In this embodiment, an internal optical path is constructed from the rotating base segment 111a back to the fixed observation window 21, thereby reliably exporting the dynamically acquired plume light signal outside the vacuum chamber.

[0030] In one embodiment, the parallel segment 111c includes a second fixed segment 111c1 and a telescopic segment 111c2 that is slidably connected to the second fixed segment 111c1, wherein the second fixed segment 111c1 and the telescopic segment 111c2 are both hollow tubes. It also includes a telescopic drive mechanism 14, which is used to drive the telescopic segment 111c2 to telescopically move relative to the second fixed segment 111c1.

[0031] This embodiment integrates the axial translation function efficiently and reliably into the periscope tube by designing the parallel section 111c as a telescopic structure. This design not only enables flexible positioning of the observation point along the main axis of the plume, making it possible to systematically measure the spatial attenuation profile of plume parameters (such as temperature, electron density, and specific spectral line intensities); it also works in conjunction with the aforementioned rotating mechanism to form a freely movable observation point, thereby achieving point-by-point scanning and comprehensive mapping of the three-dimensional spatial structure of the plasma plume, greatly enhancing the data acquisition capability and scientific research value of the observation device.

[0032] In one embodiment, the telescopic drive mechanism 14 includes a rack 141 disposed on the telescopic section 111c2, and a telescopic drive assembly disposed on the second fixed section 111c1; The telescopic drive assembly includes a second rotary drive component 142 and a drive gear 143 disposed on the output shaft of the second rotary drive component 142. The drive gear 143 meshes with the rack 141 to drive the telescopic section 111c2 to translate along its axial direction.

[0033] The gear-rack drive mechanism in this embodiment is not only compact and easy to integrate into a vacuum pipeline, but also achieves precise control of the axial position of the observation end by accurately converting rotational motion into linear displacement.

[0034] In one embodiment, a sensor mounting bracket 15 is provided on the outer wall of the second end of the periscope pipe assembly 11 for mounting a probe sensor.

[0035] The sensor mounting bracket 15 in this embodiment spatially integrates the non-invasive optical observation path with the contact (or non-contact) probe diagnostic point, ensuring that optical and electrical signals are collected from the same microscopic region of the plume at the same time. This greatly enhances the spatiotemporal correlation and comparability between measurement data of different physical quantities. This design not only avoids the spatial interference, flow field disturbance, and installation difficulties caused by setting up complex positioning mechanisms for the probe separately in the vacuum chamber 2, but also significantly improves the functional density, integration, and experimental efficiency of the entire diagnostic system. It provides strong technical support for the comprehensive and in-depth characterization of the physicochemical properties of plasma plumes, enabling the simultaneous acquisition of multi-dimensional information such as morphology, spectrum, and plasma parameters in a single experiment, greatly improving the value and reliability of scientific data.

[0036] In one embodiment, two adjacent tubes 111 are connected by a tube connector 112, the two ends of which are connecting ends for connecting tubes 111 and are at an angle, and a reflector 12 for changing the optical path is provided in the middle.

[0037] In this embodiment, the reflector 12 is securely integrated into the middle of the tube connector 112, providing optimal protection and positioning and effectively avoiding the risk of misalignment caused by separate installation. This also facilitates the connection and assembly of the tube 111.

[0038] In one embodiment, the first and second ends of the periscope-type pipe assembly 11 are both flared structures that gradually expand outward toward their openings.

[0039] For the second end, which serves as the light acquisition inlet, the flared opening effectively increases its receiving solid angle, thereby capturing radiation from the plasma plume over a larger spatial range and from more angles, significantly improving the collection efficiency of weak light signals. For the first end, which serves as the light outlet, the flared opening facilitates the coupling of internally transmitted light to the observation window 21 of the vacuum chamber 2 in a smoother and more divergent manner. This reduces the stringent alignment requirements when docking with external observation equipment such as high-speed cameras and spectrometers, and improves the compatibility and stability of the optical path output.

[0040] The above description is merely an embodiment and does not constitute any limitation on the present invention. Any person skilled in the art can make many possible variations, modifications, or alterations to the technical solutions of the present invention without departing from the scope of the present invention. Therefore, any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the present invention, should fall within the protection scope of the present invention.

Claims

1. A plasma vacuum plume observation device arranged in a vacuum chamber (2), characterized in that include: The periscope pipe assembly (11) is composed of multiple tubes (111) connected in sequence, and a reflector (12) for changing the optical path is provided between adjacent tubes (111). The first end of the periscope pipe assembly (11) faces the observation window (21) of the vacuum chamber (2), and the second end is set to face downstream of the nozzle (31) of the nozzle (3), so that the light of the plasma plume from the nozzle (31) of the nozzle (3) incident from the second end can be changed by the reflector (12) and then emitted from the first end to the observation window (21).

2. The plasma vacuum plume observation device of claim 1, wherein, The second end is capable of performing at least one of the following movements: circumferential rotation about the nozzle (31) axis of the nozzle (3), and axial translation along the nozzle (31) axis of the nozzle (3).

3. The plasma vacuum plume observation device of claim 2, wherein, The periscope-style pipe assembly (11) includes multiple pipe bodies (111) connected in sequence, specifically including: The rotating base section (111a) has its axis coaxial with the nozzle (31) axis of the nozzle (3). The first fixed section (111a1) of the rotating base section (111a) is connected to the vacuum chamber (2), and its rotating section (111a2) can rotate around its own axis. A rotary drive mechanism (13) is used to drive the rotary segment (111a2) to rotate; The first vertical segment (111b) is connected at one end to the rotating segment (111a2) and is connected at 90° to the rotating base segment (111a); The parallel segment (111c) is connected to the other end of the first vertical segment (111b) and is configured to be parallel to the axis of the nozzle (31) of the nozzle (3); The second vertical section (111d) is connected to the parallel section (111c), and its outlet forms the second end of the periscope pipe assembly (11) and is spaced from the nozzle (31) axis of the nozzle (3).

4. The plasma vacuum plume observation device of claim 3, wherein, The first fixed section (111a1) and the rotating section (111a2) of the rotating base section (111a) are hollow tubes that are rotatably connected to each other; The rotary drive mechanism (13) includes an external gear (131) disposed on the outer wall of the rotary segment (111a2) and a drive assembly. The drive assembly includes a first rotary drive member (132) and a drive gear (133) driven therefrom. The drive gear (133) meshes with the external gear (131) to drive the rotary segment (111a2) to rotate around its axis.

5. The plasma vacuum plume observation device of claim 3, wherein, The other end of the first fixed section (111a1) of the rotating base section (111a) extends toward the observation window (21) of the vacuum chamber (2) through one or more tubes (111).

6. The plasma vacuum plume observation device of claim 3, wherein, The parallel section (111c) includes a second fixed section (111c1) and a telescopic section (111c2) that is slidably connected to the second fixed section (111c1). Both the second fixed section (111c1) and the telescopic section (111c2) are hollow tubes. It also includes a telescopic drive mechanism (14) for driving the telescopic segment (111c2) to telescopically move relative to the second fixed segment (111c1).

7. The plasma vacuum plume observation device of claim 6, wherein, The telescopic drive mechanism (14) includes a rack (141) disposed on the telescopic section (111c2) and a telescopic drive assembly disposed on the second fixed section (111c1); The telescopic drive assembly includes a second rotary drive member (142) and a drive gear (143) disposed on the output shaft of the second rotary drive member (142). The drive gear (143) meshes with the rack (141) to drive the telescopic section (111c2) to translate along its axial direction.

8. A plasma vacuum plume observation device according to any one of claims 1-7, characterized in that The outer wall of the second end of the periscope pipe assembly (11) is provided with a sensor mounting bracket (15), which is used to mount a probe sensor.

9. A plasma vacuum plume observation device according to any one of claims 1-7, characterized in that The two adjacent tubes (111) are connected by tube connectors (112). The two ends of the tube connectors (112) are connecting ends for connecting the tubes (111) and are at an angle. A reflector (12) for changing the optical path is provided in the middle.

10. The plasma vacuum plume observation device of any one of claims 1-7, wherein, The first and second ends of the periscope-type pipe assembly (11) are both funnel-shaped structures that gradually expand outward toward their openings.

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