Neutral atom detection device based on nested detection channels

Abstract

This invention discloses a neutral atom detection device based on nested detection channels, including a detector comprising an ion deflection mechanism and an electrostatic analyzer. The ion deflection mechanism includes multiple deflecting elements and multiple ionizing elements arranged coaxially. A detection channel is formed by the gap between two deflecting elements, and the multiple detection channels are arranged in a ring-shaped detection field of view, spaced out from the inside, to collect neutral atoms incident from the satellite's orbital space. The multiple ionizing elements are nested from the inside out, with neutral atoms introduced into each detection channel entering the ionizing element at a corresponding grazing incidence angle. The electrostatic analyzer includes a first electrode and a second electrode, with a first passage between them, which deflects positively charged ions entering through the multiple detection channels. A turntable is mounted on a satellite platform, configured to rotate, and the detector is mounted on the turntable. The effective area of ​​the nested detection channel is significantly increased.

Description

Technical Field

[0001] This invention relates to the technical field of space environment detection, and in particular to a neutral atom detection device based on nested detection channels. Background Technology

[0002] Charged ions and neutral atoms (ENA) exist everywhere in Earth's space, interplanetary space, and deep space around other planets in the solar system. Charged ions can become neutral atoms through charge exchange (accepting an electron), and neutral atoms can become charged ions through charge exchange (losing an electron). The charge exchange process between charged ions and neutral atoms reflects the fundamental physical mechanisms of energy transfer in space. Therefore, measuring information about charged ions and neutral atoms in space can be used to study fundamental physical questions of interest to humanity, such as how low-energy particles are accelerated to high-energy particles, and how the sun influences the formation and dissipation of planetary atmospheres. Solving these problems helps humanity understand the unknown world and provides a guarantee for the safe conduct of various human space activities.

[0003] Neutral atoms are uncharged and their motion is unaffected by electric and magnetic fields in space, making them useful for retrieving the state of distant plasma regions. Therefore, neutral atom detection is widely used as a remote sensing method in space environment exploration, achieving unique detection results. Currently, neutral atom detectors are deployed on several space science satellites, including the US IMAGE and IBEX, the European Space Agency's Mars Express and JUICE, and China's Tianwen-1 mission, to detect neutral atoms in space.

[0004] The common method for measuring neutral atoms is to first ionize them into charged ions, and then measure them using methods for measuring charged ions. There are two main ionization methods: grazing-incidence ionization plates and penetrating ultrathin films. A typical example of a grazing-incidence ionization plate neutral atom detector is the MINPA (Ion and Neutral Particle Analyzer) on China's Tianwen-1 Mars probe. MINPA integrates both ion and neutral atom detection functions, enabling the detection of low-energy neutral atoms. The efficiency of neutral atoms generated by the interaction between neutral atoms and the ionization plate is typically low (approximately a few percent or less). A larger effective detection area results in higher detection sensitivity, which is more advantageous for detecting low-flux neutral atoms in the environment. However, a drawback of the existing MINPA neutral atom detector is its relatively small effective detection area, which is detrimental to the detection of low-flux neutral atoms. Summary of the Invention

[0005] This invention provides a neutral atom detection device based on nested detection channels, comprising: a detector, which includes an ion deflection mechanism and an electrostatic analyzer; wherein the ion deflection mechanism includes multiple deflecting elements and multiple ionizing elements arranged coaxially; wherein the deflecting elements are cylindrical sleeves, and the multiple deflecting elements are nested sequentially from the inside out, the gap between two deflecting elements forming a detection channel, and the multiple detection channels are annular detection fields of view distributed sequentially from the inside out, used to collect neutral atoms incident from the satellite orbit space, and capable of shielding charged particles incident from the satellite orbit space; the ionizing elements are frustum-shaped sleeves, and the multiple ionizing elements are nested sequentially from the inside out, the neutral atoms introduced into each detection channel enter the ionizing element at a corresponding grazing incidence angle, and are ionized into positively charged ions by the ionizing element. The system includes an electrostatic analyzer comprising a first electrode and a second electrode, with a first passage between the first and second electrodes. The first passage is used to deflect positively charged ions entering through multiple detection channels, and the energy of the positively charged ions entering the first passage is analyzed by a voltage applied by the second electrode. A turntable is mounted on a satellite platform and is configured to rotate. The detector is mounted on the turntable. The ion deflection mechanism is configured to extend axially along a first direction to collect neutral atoms incident along the first direction in the satellite's orbital space. When the turntable rotates, it drives the detector to rotate, thereby detecting neutral atoms incident circumferentially along the detector in the satellite's orbital space. The axes of the multiple detection channels are perpendicular to the axes of the first and second electrodes.

[0006] Furthermore, the ionizing element is configured to gradually tilt along the axis of the detection channel, with the larger end of the ionizing element close to the exit end of the detection channel and the smaller end of the ionizing element close to the electrostatic analyzer; the tilt angle formed by the sidewall of the ionizing element and the axis of the detection channel is set to 10°-15°.

[0007] Furthermore, the deflecting element includes: a first deflecting element, a second deflecting element, a third deflecting element, and a fourth deflecting element arranged sequentially from the inside out, the gap between the first deflecting element and the second deflecting element forming a first detection channel, and the gap between the third deflecting element and the fourth deflecting element forming a second detection channel.

[0008] Furthermore, the ionization element includes a first ionization element and a second ionization element nested sequentially from the inside out. The inner diameter of the larger end of the first ionization element is larger than the outer diameter of the second deflector element, and the inner diameter of the larger end of the second ionization element is larger than the outer diameter of the fourth deflector element; wherein,

[0009] Neutral atoms incident on the first detection channel enter the first ionization element at a grazing incidence angle and are ionized into positively charged ions by the first ionization element;

[0010] Neutral atoms incident on the second detection channel enter the second ionization element at a grazing incidence angle and are ionized into positively charged ions by the second ionization element.

[0011] Furthermore, the voltage polarity between the first deflector and the second deflector is set to be opposite, the voltage polarity between the third deflector and the fourth deflector is set to be opposite, and the voltage polarity between the second deflector and the third deflector is set to be the same.

[0012] The voltage outside the sidewall of the ionization element is higher than the voltage inside the sidewall.

[0013] Furthermore, the neutral atom detection device further includes:

[0014] A lens assembly is located between the ion deflection mechanism and the electrostatic analyzer. The lens assembly includes a first lens and a second lens, with the first lens located between the second lens and the electrostatic analyzer.

[0015] The first lens has a through first hole, and the second lens has a through second hole, the second hole and the first hole are connected to form a second passage;

[0016] Both the first lens and the second lens are connected to a negative voltage to form an electric field distribution. This electric field distribution can accelerate and focus positively charged ions entering the second path via the first and second detection channels so that they can enter the first path.

[0017] Furthermore, the ion deflection mechanism further includes:

[0018] A focusing electrode is used to focus positively charged ions ionized in the first and second ionizing elements onto the second hole of the second lens. The focusing electrode is sleeved on the outside of the second ionizing element, and the voltage of the focusing electrode is greater than the voltage of the sidewall of the second ionizing element.

[0019] Furthermore, the focusing electrode has a protrusion on the side near the second lens. The protrusion is gradually inclined along the axis of the detection channel and gradually contracts in the direction close to the second lens. The inclination angle formed by the protrusion and the axis of the detection channel is less than 60 degrees.

[0020] Furthermore, the neutral atom detection device further includes:

[0021] The time-of-flight system is used to generate the start and end point electrical signals of positively charged ions within a fixed flight distance, output from the electrostatic analyzer.

[0022] The electronics processing unit processes the electrical signals output by the time-of-flight system to obtain information on the direction, energy, and composition of positively charged ions; among which,

[0023] Based on the measured energy of the positively charged ions, combined with the voltage of the first lens and the voltage inside the sidewall of the ionization element, the energy of the neutral atom is calculated according to the following conditional formula:

[0024] E = E0 - C × e × (V2 - V1)

[0025] In the formula, E is the energy of the neutral atom; E0 is the energy of the positively charged ion measured; V1 is the voltage of the first lens; V2 is the voltage inside the ionization element; C is a constant, which is related to the parameters and configuration of the focusing electrode, ionization element and lens assembly; and e is the amount of electron charge.

[0026] Furthermore, the turntable is configured to swing upwards or downwards to detect neutral atoms incident along the pitch direction of the detector within the satellite's orbital space.

[0027] The above-described technical solution of the present invention has the following beneficial technical effects:

[0028] In this embodiment of the invention, each detection channel is a circular detection field of view, and multiple detection channels are nested detection channels arranged sequentially from the inside out. When collecting neutral atoms incident along the first direction in the satellite's orbital space, the effective area of ​​each detection channel is the area of ​​the entire circular ring. Compared with the detection window being multiple fan-shaped holes in the circumferential direction, the effective area of ​​the nested detection channels in this embodiment of the invention is significantly increased, which improves the sensitivity of the detector and is more advantageous for detecting low-flux neutral atoms in the environment. Furthermore, by mounting the detector on a turntable and rotating the turntable 360 ​​degrees circumferentially, neutral atoms incident along the circumference of the detector in the satellite's orbital space can be collected, expanding the detector's detection range in the satellite's orbital space. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the detection principle of the MINPA ion and neutral particle analyzer in related technologies;

[0030] Figure 2 This is a schematic diagram of the structure of a neutral atom detection device based on a nested detection channel according to the first embodiment of the present invention;

[0031] Figure 3 This is a schematic diagram of the structure of a neutral atom detection device based on a nested detection channel according to a second embodiment of the present invention;

[0032] Figure 4 This is a schematic diagram of the structure of a neutral atom detection device based on a nested detection channel according to a third embodiment of the present invention;

[0033] Figure label:

[0034] 1. First deflection plate; 2. Second deflection plate; 3. Ionization plate; 4. Hypertoroidal analyzer; 5. Time-of-flight assessment unit;

[0035] 10. Ion deflection mechanism; 11. Housing; 12. First deflector; 13. Second deflector; 14. Third deflector; 15. Fourth deflector; 16. First ionizer; 17. Second ionizer; 18. First lens; 19. Second lens; 20. Focusing electrode; 21. First detection channel; 22. Second detection channel; 30. Electrostatic analyzer; 31. First electrode; 32. Second electrode; 40. Turntable; 50. Time-of-flight system; 60. Electronics processing unit. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention. In this document, terms such as first, second, and third are used only to distinguish one feature from another and are not intended to require or imply any order or association between these features.

[0037] A typical example of a grazing incidence ionization plate neutral atom detector is the MINPA (Ion and Neutral Particle Analyzer) on China's Tianwen-1 Mars mission. The MINPA analyzer's detection principle is as follows: Figure 1 As shown, the MINPA analyzer integrates both ion and neutral atom detection functions, with a neutral atom detection energy range of 50 eV-3 keV. For neutral atom detection, neutral atoms enter through the side detection window, first passing through the first deflection plate 1 and the second deflection plate 2, and then striking the ionization plate 3 at a grazing incidence. High voltage is applied to the first deflection plate 1 and the second deflection plate 2 to form a deflecting electric field, deflecting the charged particles incident along with the neutral atoms and preventing interference with neutral atom detection. The neutral atoms strike the ionization plate at a 15° grazing incidence angle, and some are ionized into positively charged ions. The ionized ions are deflected by the electric field formed by the voltage applied by the lens and accelerated to the entrance of the toroidal analyzer 4. The toroidal analyzer 4 consists of inner and outer hemispherical shells, with a deflecting electric field formed between the inner and outer hemispheres, allowing only ions with a specific energy-to-charge ratio to pass through. Voltage scanning of the inner hemisphere shell allows for analysis of the energy of the ionized ions. Ions emitted from the supertoroidal analyzer 4 enter the time-of-flight assessment unit 5, where the flight time of the ions over a fixed distance is measured to determine the composition of the ions and the corresponding neutral atom composition information. However, the above... Figure 1The MINPA analyzer in China has a detection field of view for neutral atoms that consists of 16 detection windows distributed in a 360° circumferential direction. Each detection window has a detection field of view of a fan-shaped channel (22.5°×15°). The disadvantage is that the effective detection area is small, which is not conducive to the detection of low-throughput neutral atoms.

[0038] In view of this, embodiments of the present invention provide a neutral atom detection device based on nested detection channels, such as... Figure 2-4 As shown, the system includes a detector and a turntable 40. The detector includes an ion deflection mechanism 10 and an electrostatic analyzer 30. The ion deflection mechanism 10 includes multiple deflecting elements and multiple ionizing elements arranged coaxially. Each deflecting element is a cylindrical sleeve, and the multiple deflecting elements are arranged sequentially from the inside out. The gap between two deflecting elements forms a detection channel. The multiple detection channels form an annular detection field of view, arranged sequentially from the inside out, used to collect neutral atoms incident from the satellite's orbital space and to shield charged particles incident from the satellite's orbital space. Each ionizing element is a frustum-shaped sleeve, and the multiple ionizing elements are arranged sequentially from the inside out. Neutral atoms introduced into each detection channel enter the ionizing element at a grazing incidence angle and are ionized into positively charged ions. The electrostatic analyzer 30 includes a first electrode 31 and a second electrode 32 arranged coaxially from the outside in. The first electrode 31 and the second electrode 32 are arc-shaped plates. The detector has a structure with a first passage between the first electrode 31 and the second electrode 32. The first passage is used to deflect positively charged ions entering through the multiple detection channels. The voltage applied by the second electrode 32 is used to analyze the energy of the positively charged ions entering the first passage. A turntable 40 is mounted on the satellite platform and is configured to rotate. The detector is mounted on the turntable 40. The ion deflection mechanism is configured to extend axially along a first direction to collect neutral atoms incident along the first direction in the satellite's orbital space. When the turntable 40 rotates, it drives the detector to rotate, thereby detecting neutral atoms incident circumferentially along the detector in the satellite's orbital space. The axes of the multiple detection channels are perpendicular to the axes of the first electrode 31 and the second electrode 32, and the axes of the multiple detection channels are perpendicular to the axis of the turntable 40.

[0039] Specifically, the ion deflection mechanism 10 may further include a housing 11, and a plurality of deflection elements and a plurality of ionization elements arranged coaxially may be installed inside the housing 11. The housing 11 may be provided with insulating polyimide material. Figure 3 and Figure 4(Not shown in the image) is used to support and isolate various components. The housing 11 can be grounded. The deflecting element is, for example, a deflecting electrode. The deflecting element can be a cylindrical sleeve. The gap between two deflecting elements forms a detection channel. Applying voltages of opposite polarities to the two deflecting elements will create a ring-shaped electric field perpendicular to the deflecting elements in the detection channel. This field guides neutral atoms incident in the satellite's orbital space and deflects charged particles that are incident with the neutral atoms, preventing the charged particles from passing through the detection channel. The introduced neutral atoms hit the ionizing element at a 15-degree grazing incident angle. Each ionizing element corresponds to a ring-shaped detection channel. The ionizing element is a frustum-shaped sleeve with a smooth inclined inner wall. The surface of the inner wall is coated with an aluminum oxide film to achieve partial ionization of neutral atoms into positively charged ions. The first electrode 31 and the second electrode 32 are coaxially arranged arc-shaped sheet structures. The arc diameter of the first electrode 31 is larger than that of the second electrode 32. For example, the end face of the arc-shaped sheet structure is set as 1 / 4 of a circle, that is, the included angle between the centers of the arc-shaped sheet structure is 90 degrees. Positively charged ions from multiple detection channels converge and enter the first passage between the first electrode 31 and the second electrode 32 of the electrostatic analyzer 30. The voltage applied by the second electrode 32 is used to analyze the energy of the positively charged ions entering the first passage. The turntable 40 is configured to rotate. For example, the turntable 40 may be equipped with a driven wheel, a driving wheel, and a drive motor. The driving wheel may be mounted on the output shaft of the drive motor, and the driven wheel may be mounted on the rotating shaft of the turntable 40. The drive motor drives the driving wheel, and through the meshing transmission of the driving wheel and the driven wheel, the turntable 40 is rotated, thereby causing the detector mounted on the turntable 40 to rotate circumferentially. The ion deflection mechanism 10 may be set on one side of the electrostatic analyzer 30, with the axis of the detection channel aligned with the first electrode 31 and the second electrode 32. The axis of the detector is approximately perpendicular to the axis of the turntable 40. By rotating the turntable 40, neutral atoms incident along the circumference of the detector within the satellite's orbital space can be detected. The first direction can be any direction within the satellite's orbital space. Each detector channel is a circular field of view, and multiple detector channels are nested detector channels arranged alternately from the inside out. When collecting neutral atoms incident along the first direction within the satellite's orbital space, the effective area of ​​each detector channel is the area of ​​the entire circular ring. Compared to multiple fan-shaped holes in the circumferential direction for the detector window, the effective area of ​​the nested detector channels in this embodiment of the invention is significantly increased, improving the detector's sensitivity and making it more advantageous for detecting low-flux neutral atoms in the environment. Furthermore, by mounting the detector on the turntable and rotating the turntable 360 ​​degrees, neutral atoms incident along the circumference of the detector within the satellite's orbital space can be collected, expanding the detector's detection range within the satellite's orbital space.

[0040] In particle detection, a commonly used factor for assessing detection sensitivity is the geometric factor, which is calculated as: Geometric Factor = Detection Area × Detection Solid Angle. The geometric factor represents the combined sensitivity of the detection instrument to area and angle. If the diameter of the smallest inner ring detection channel is equal to the above... Figure 1 In the MINPA detector, the diameter of the circle forming the channel between the first deflection plate 1 and the second deflection plate 2 is the same, and the slit width of the channel is also the same. Therefore, the geometric factor of the inner ring detection channel in this embodiment is as described above. Figure 1 The effective area of ​​the detection channel in this embodiment of the invention is increased by more than 32 times, which is 16 times that of the MINPA detector in the inner ring and more than 16 times that of the outer ring detection channel.

[0041] In this embodiment of the invention, the neutral atom detection device may further include: a time-of-flight system 50, used to generate starting and ending electrical signals within a fixed flight distance based on the ion generation signals output from the electrostatic analyzer 30; and an electronics processing unit 60, used to process the electrical signals output from the time-of-flight system 50 to obtain the direction, energy, and composition information of the positively charged ions and neutral atoms. The electronics processing unit 60 can be installed inside a housing, the electrostatic analyzer 30 and the time-of-flight system 50 can be installed on the top surface of the housing, the housing 11 of the ion deflection mechanism 10 can also be installed on the housing, and the housing can be mounted on a turntable 40. Figure 2 The arrows shown indicate the direction of the electrical signal output from the time-of-flight system 50 to the electronics processing unit 60. The first electrode 31 and the second electrode 32 of the electrostatic analyzer 30 are coaxially arranged arc-shaped sheet structures with an included angle of 90 degrees between their centers. That is, the bottom surface of the arc of the first electrode 31 and the second electrode 32 is parallel to the top surface of the turntable 40. The ion deflection mechanism 10 can be located on one side of the electrostatic analyzer 30, and the time-of-flight system 50 can be located on the other side of the electrostatic analyzer 30. The flight channel carrying positively charged ions into the time-of-flight system 50 is located on the same arc as the first passage, thus shortening the flow path of positively charged ions. Figure 2 The dotted lines represent the incident paths of neutral atoms, and the dashed lines represent the trajectories of positively charged ions after ionization. Figure 2 The arrow shown indicates that the electrical signal output by the time-of-flight system 50 is sent to the electronics processing unit 60.

[0042] In some embodiments, the ionizing element is configured to gradually tilt along the axis of the detection channel, with the larger end of the ionizing element closer to the exit end of the detection channel and the smaller end closer to the electrostatic analyzer 30; the tilt angle formed by the sidewall of the ionizing element and the axis of the detection channel is set to 10°-15°. This allows the introduced neutral atoms to strike the inner sidewall of the ionizing element at a grazing incidence angle. The inner wall of the ionizing element is a smooth inclined surface, and its surface is coated with an aluminum oxide film, which increases the contact area with the introduced neutral atoms, thereby achieving the ionization of more neutral atoms into positively charged ions.

[0043] In some embodiments, the deflecting element includes: a first deflecting element 12, a second deflecting element 13, a third deflecting element 14, and a fourth deflecting element 15, which are sequentially arranged from the inside out. The gap between the first deflecting element 12 and the second deflecting element 13 forms a first detection channel 21, and the gap between the third deflecting element 14 and the fourth deflecting element 15 forms a second detection channel 22. The first deflecting element 12 can be filled with insulating polyimide material, and the space between the second deflecting element 13 and the third deflecting element 14 can also be filled with insulating polyimide material. The space between the fourth deflecting element 15 and the housing 11 can also be filled with insulating polyimide material. The various parts within the housing 11 can be supported by insulating material and then fixed to the housing 11 by insulating material. Therefore, a small amount of polyimide material can be filled between the first deflecting element 12 and the second deflecting element 13 to support the first deflecting element 12; and the first deflecting element 12 and the second deflecting element 13 can be subjected to insulating material. Applying a voltage of opposite polarity creates a ring-shaped electric field perpendicular to the deflector within the first detection channel 21. This field guides neutral atoms incident in the satellite's orbital space and deflects charged particles that are incident along with the neutral atoms, preventing the charged particles from passing through the detection channel. Similarly, a second detection channel 22 can be formed between the third deflector 14 and the fourth deflector 15. To avoid a high electric field between electrodes of opposite polarity that could cause a high-voltage discharge, the voltage polarity between the second deflector 13 and the third deflector 14 can be set to be the same.

[0044] In some embodiments, the ionization element includes a first ionization element 16 and a second ionization element 17 sequentially nested from the inside out. The inner diameter of the large end of the first ionization element 16 is larger than the outer diameter of the second deflector 13, and the inner diameter of the large end of the second ionization element 17 is larger than the outer diameter of the fourth deflector 15. Neutral atoms incident on the first detection channel 21 enter the first ionization element 16 at a grazing incidence angle and are ionized into positively charged ions by the first ionization element 16. Neutral atoms incident on the second detection channel 22 enter the second ionization element 17 at a grazing incidence angle and are ionized into positively charged ions by the second ionization element 17. By setting the first ionizing element 16 and the second ionizing element 17 as a frustum-shaped sleeve, with the inner diameter of the large end of the first ionizing element 16 being larger than the outer diameter of the second deflecting element 13, and the inner diameter of the large end of the second ionizing element 17 being larger than the outer diameter of the fourth deflecting element 15, it is beneficial for neutral atoms to enter the ionizing element at a grazing incidence angle, and the contact area with neutral atoms is increased. Combined with setting the external voltage of the sidewall of the ionizing element to be higher than the internal voltage of the sidewall, the trajectory of the positively charged ions after ionization can be adjusted. In this way, the positively charged ions after ionization can be accelerated and focused in a preset direction.

[0045] In some embodiments, the neutral atom detection device further includes a lens assembly located between the ion deflection mechanism 10 and the electrostatic analyzer 30. The lens assembly includes a first lens 18 and a second lens 19, with the first lens 18 located between the second lens 19 and the electrostatic analyzer 30. The first lens 18 has a through-hole, and the second lens 19 has a through-hole, with the second hole and the first hole connected to form a second passage. Both the first lens 18 and the second lens 19 are connected to a negative voltage to form an electric field distribution. This electric field distribution can accelerate and focus positively charged ions entering the second passage via the first detection channel 21 and the second detection channel 22, so that they enter the first passage. Specifically, the lens assembly can be installed inside the housing 11. The first lens 18 and the second lens 19 can be, for example, cylinders made of metal. Both the first lens 18 and the second lens 19 are connected to a negative voltage to form an electric field distribution. Neutral atoms introduced through the first detection channel 21 and the second detection channel 22 are ionized into positively charged ions, which can then pass through the second lens 19 and the first lens 18 in sequence before entering the electrostatic analyzer 30. In this way, by setting the second lens 19 and the first lens 18 and configuring the voltage polarity, it can be ensured that the positively charged ions ionized by the first ionization element 16 and the second ionization element 17 are accelerated and effectively focused before entering the electrostatic analyzer 30.

[0046] In some embodiments, the ion deflection mechanism 10 further includes a focusing electrode 20, which is used to converge positively charged ions ionized in the first ionizing element 16 and the second ionizing element 17 to the second hole of the second lens 19. The focusing electrode 20 is sleeved on the outside of the second ionizing element 17, and the voltage of the focusing electrode 20 is greater than the sidewall voltage of the second ionizing element 17. Insulating polyimide material can be filled between the focusing electrode 20 and the housing 11 to support the focusing electrode 20. Insulating polyimide material can also be filled between the focusing electrode 20 and the second ionizing element 17 to support the second ionizing element 17. A small amount of polyimide material can be filled between the first ionizing element 16 and the second ionizing element 17 to support the first ionizing element 16. By setting the focusing electrode 20 and setting its voltage to be greater than the sidewall voltage of the ionizing element, the positively charged ions ionized by the formed electric field are accelerated and effectively converged before entering the electrostatic analyzer 30.

[0047] In some embodiments, the focusing electrode 20 has a protrusion on the side near the second lens 19. The protrusion gradually slopes along the axis of the detection channel and gradually narrows towards the second lens 19; wherein the slope angle formed by the protrusion and the axis of the detection channel is less than 60 degrees. By setting the protrusion of the focusing electrode 20 to a constricted structure, and by setting the voltage of the focusing electrode 20 to be greater than the sidewall voltage of the ionizing element, and by setting the voltage of the second lens 19 to be negative, the positively charged ions ionized by the two nested ionizing elements can be accelerated and effectively converged, flowing into the second lens 19 according to a preset trajectory.

[0048] In some embodiments, the energy of the neutral atom is calculated based on the measured energy of the positively charged ions, combined with the voltage of the first lens 18 and the voltage within the sidewall of the ionization element, according to the following conditional formula:

[0049] E = E0 - C × e × (V2 - V1)

[0050] In the formula, E is the energy of the neutral atom; E0 is the measured energy of the positively charged ion; V1 is the voltage of the first lens 18; V2 is the voltage inside the ionization element; C is a constant, which is related to the parameters and configuration of the focusing electrode 20, the first ionization element 16, the second ionization element 17, the first lens 18, and the second lens 19, and is determined based on simulation and experiment; e is an electron charge.

[0051] Specifically, positively charged ions passing through the first path of the electrostatic analyzer 30 enter the time-of-flight system 50. The flight time of the positively charged ions within a fixed distance is measured to obtain their velocity information. Combined with the energy of the positively charged ions measured by the electrostatic analyzer 30, the energy of the neutral atom can be calculated using the aforementioned conditional formula. The composition of the measured positively charged ions corresponds to the composition of the neutral atom. The energy of the neutral atom can be calculated simply using the above conditional formula, and the calculation result is highly accurate.

[0052] In some embodiments, the turntable 40 is configured to swing upwards or downwards to detect neutral atoms incident along the pitch direction of the detector within the satellite's orbital space. The bottom surface of the turntable 40 may be equipped with a drive assembly for driving the turntable 40 to swing upwards or downwards relative to the satellite platform, thereby enabling detection of neutral atoms incident along the pitch direction of the detector within the satellite's orbital space over a wider angular range.

[0053] The specific implementation process of this invention is described as follows:

[0054] The neutral atom detection device provided in this embodiment of the invention has two annular neutral atom detection channels, one inner and one outer. For example, the inner ring is the first detection channel 21. Incident neutral atoms first pass through the first detection channel 21 between the first deflector 12 and the second deflector 13. Applying voltages of opposite polarities to the first deflector 12 and the second deflector 13 creates an electric field perpendicular to the annular surface of the deflector, deflecting charged particles incident with the neutral atoms and preventing them from passing through the first detection channel 21. Simultaneously, the first detection channel 21 can restrict the direction of the incident neutral atoms, with the incident angle of the neutral atoms in the range of approximately 15°. The neutral atoms passing through the first detection channel 21 strike the first ionization element 16. The angle between the surface normal of the first ionization element 16 and the surface normal of the first deflector 12 is approximately 10-15°. The inner wall of the first ionization element 16 is a highly smooth inclined surface, and the surface of the inner wall can be coated with an aluminum oxide thin film. Neutral atoms, at a grazing incidence angle with the surface of the first ionization element 16, interact with the alumina film, and some neutral atoms are ionized into positively charged ions. These positively charged ions converge at the entrance of the second lens under the combined action of the inner and outer voltages of the first ionization element 16 and the voltage of the focusing electrode 20. The inner voltages of the first ionization element 16 and the second ionization element 17 are the same, thus enabling the detection of neutral atoms within the same energy range. The outer voltages of the first ionization element 16 and the second ionization element 17 are higher than their inner voltages, and the voltage of the focusing electrode 20 is greater than the outer voltage of the second ionization element 17. The focusing electrode 20 is designed with a constricted opening added to a cylindrical structure, and its negative voltage, combined with that of the second lens 19, enables effective focusing of positively charged ions in the case of two nested ionization elements.

[0055] The outer ring is the second detection channel 22, and the principle of detecting neutral atoms incident on it is similar to that of detecting neutral atoms incident on the inner ring.

[0056] The first lens 18 and the second lens 19 are both circular metal plates with a hollowed-out center, forming a positively charged ion channel. Both lenses 18 and 19 are subjected to a negative voltage, creating an electric field distribution that accelerates and focuses the positively charged ions. The positively charged ions ionized from the inner and outer annular detection channels are accelerated and focused by the voltages of the first lens 18 and the second lens 19, respectively, before entering the channel of the electrostatic analyzer 30. A negative voltage is applied to the second electrode 32 of the electrostatic analyzer 30, while the first electrode 31 is grounded. A deflection electric field is formed between the first electrode 31 and the second electrode 32, deflecting the incident positively charged ions. The energy of the positively charged ions passing through the first path of the electrostatic analyzer 30 is related to the voltage applied to the second electrode 32. The positively charged ions passing through the first path of the electrostatic analyzer 30 enter the time-of-flight system 50. Positively charged ions penetrate a thin film at the entrance of the time-of-flight system, generating secondary electrons through interaction with the film. These secondary electrons are collected as the initial electrical signal of the ion within the time-of-flight system. The positively charged ions continue their flight, penetrating another thin film at the exit of the time-of-flight system, generating secondary electrons through interaction with the film again. These secondary electrons are collected as the termination electrical signal of the ion within the time-of-flight system. The time difference between the termination electrical signal and the initial electrical signal is measured, which represents the flight time of the positively charged ion over a fixed distance, thus obtaining the ion's velocity information. Combined with the energy information of the positively charged ions measured by the electrostatic analyzer 30, the mass (composition) information of the positively charged ions can be obtained. The composition of the positively charged ions corresponds to the composition of the neutral atoms. The energy E of the neutral atoms is calculated by combining the measured energy E0 of the positively charged ions with the voltage V1 of the first lens 18 and the inner voltage V2 of the ionization element: E = E0 - C × e × (V2 - V1). C and e are both constants. C is related to the parameters and configuration of the focusing electrode 20, the first ionization element 16, the second ionization element 17, the first lens 18, and the second lens 19, and is determined based on simulation and experiment. e is an electron charge.

[0057] For example, when the neutral atom energy E to be detected is 1keV, the voltage difference between the outer and inner voltages of the first ionizing element 16 and the second ionizing element 17 is set to about 400V. The voltage of the focusing electrode 20 is greater than the outer voltage of the ionizing element, and the voltage difference between the two does not exceed 3000V, thus forming a deflection electric field. Finally, the direction of the electric field is along the trajectory of the positively charged ions and points to the entrance of the second lens 19. The voltages applied to each component are as follows: the voltage of the first deflector 12 is -5000V; the voltage of the second deflector 13 is +5000V; the voltage of the third deflector 14 is +5000V; the voltage of the fourth deflector 15 is -5000V; the inner voltage of the first ionizer 16 is the same as the inner voltage of the second ionizer 17, which is +1200V; the outer voltage of the first ionizer 16 is the same as the outer voltage of the second ionizer 17, which is +1600V; the voltage of the focusing electrode 20 is +2600V; the voltage of the first lens 18 is -1000V; and the voltage of the second lens 19 is -1600V.

[0058] The advantages of the technical solution of this invention are:

[0059] (1) Compared with existing detection instruments, the neutral atom detection device of the present invention expands the detection channel from a fan-shaped field of view to two annular detection fields of view with minimal resources, thereby increasing the effective detection area by more than 32 times, greatly improving the detection sensitivity of the detector, which is beneficial for the detection of low-throughput neutral atoms; and the annular detection fields of view can also significantly increase the effective detection area by increasing the number of nested layers.

[0060] (2) To detect neutral atoms in a specific direction in the satellite's orbital space, the effective detection area of ​​the neutral atom detection device in this embodiment of the invention has been greatly improved. In order to expand the detection range of the detector in the satellite's orbital space, the detector is installed on a turntable. The 360-degree circumferential rotation of the turntable and the up-and-down swing of the turntable are used to achieve a wider range of detection of neutral atoms.

[0061] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of the invention and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the invention should be included within the protection scope of the invention. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A neutral atom detection device based on nested detection channels, characterized in that, include: The detector includes an ion deflection mechanism and an electrostatic analyzer; among which, The ion deflection mechanism includes multiple deflecting elements and multiple ionization elements arranged coaxially; among which, The deflector is a cylindrical sleeve, and multiple deflectors are arranged sequentially from the inside to the outside. The gap between two deflectors forms a detection channel. The multiple detection channels are annular detection fields of view that are arranged sequentially from the inside to the outside. They are used to collect neutral atoms incident from the satellite's orbital space and can shield charged particles incident from the satellite's orbital space. The ionization element is a frustum-shaped sleeve, and multiple ionization elements are arranged sequentially from the inside to the outside. Neutral atoms introduced into each detection channel enter the ionization element at a grazing incidence angle and are ionized into positively charged ions. The electrostatic analyzer includes a first electrode and a second electrode arranged coaxially and distributed from the outside to the inside. The first electrode and the second electrode are arc-shaped sheet structures, and there is a first passage between the first electrode and the second electrode. The first passage is used to deflect positively charged ions that enter through the multiple detection channels. The voltage applied by the second electrode is used to perform energy analysis on the positively charged ions that enter the first passage. A turntable, mounted on a satellite platform, is configured to rotate, and the detector is mounted on the turntable; wherein... The ion deflection mechanism is designed to extend axially along the first direction to collect neutral atoms incident along the first direction in the satellite's orbital space. When the turntable rotates, it drives the detector to rotate, so as to detect neutral atoms incident along the circumference of the detector in the satellite's orbital space. The axes of the plurality of detection channels are perpendicular to the axes of the first electrode and the second electrode.

2. The neutral atom detection device according to claim 1, characterized in that, The ionizing element is configured to gradually tilt along the axis of the detection channel, with the large end of the ionizing element close to the emission end of the detection channel and the small end of the ionizing element close to the electrostatic analyzer. The inclination angle between the sidewall of the ionization device and the axis of the detection channel is set to 10°-15°.

3. The neutral atom detection device according to claim 2, characterized in that, The deflector includes: The first deflector, the second deflector, the third deflector, and the fourth deflector are sequentially arranged from the inside out. The gap between the first deflector and the second deflector forms the first detection channel, and the gap between the third deflector and the fourth deflector forms the second detection channel.

4. The neutral atom detection device according to claim 3, characterized in that, The ionization element includes a first ionization element and a second ionization element nested sequentially from the inside out. The inner diameter of the larger end of the first ionization element is larger than the outer diameter of the second deflector element, and the inner diameter of the larger end of the second ionization element is larger than the outer diameter of the fourth deflector element. Neutral atoms incident on the first detection channel enter the first ionization element at a grazing incidence angle and are ionized into positively charged ions by the first ionization element; Neutral atoms incident on the second detection channel enter the second ionization element at a grazing incidence angle and are ionized into positively charged ions by the second ionization element.

5. The neutral atom detection device according to claim 3, characterized in that, The voltage polarity between the first deflector and the second deflector is set to be opposite, the voltage polarity between the third deflector and the fourth deflector is set to be opposite, and the voltage polarity between the second deflector and the third deflector is set to be the same. The voltage outside the sidewall of the ionization element is higher than the voltage inside the sidewall.

6. The neutral atom detection device according to claim 5, characterized in that, The detector also includes: A lens assembly is located between the ion deflection mechanism and the electrostatic analyzer. The lens assembly includes a first lens and a second lens, with the first lens located between the second lens and the electrostatic analyzer. The first lens has a through first hole, and the second lens has a through second hole, the second hole and the first hole are connected to form a second passage; Both the first lens and the second lens are connected to a negative voltage to form an electric field distribution. This electric field distribution can accelerate and focus positively charged ions entering the second path via the first and second detection channels so that they can enter the first path.

7. The neutral atom detection device according to claim 6, characterized in that, The ion deflection mechanism further includes: A focusing electrode is used to focus positively charged ions ionized in the first and second ionizing elements onto the second hole of the second lens. The focusing electrode is sleeved on the outside of the second ionizing element, and the voltage of the focusing electrode is greater than the voltage of the sidewall of the second ionizing element.

8. The neutral atom detection device according to claim 7, characterized in that, The focusing electrode has a protrusion on the side near the second lens. This protrusion gradually slopes along the axis of the detection channel and gradually tapers towards the second lens. The angle of inclination between the protrusion and the axis of the detection channel is less than 60 degrees.

9. The neutral atom detection device according to claim 6, characterized in that, The detector also includes: The time-of-flight system is used to generate the start and end point electrical signals of positively charged ions within a fixed flight distance, output from the electrostatic analyzer. The electronics processing unit processes the electrical signals output by the time-of-flight system to obtain information on the direction, energy, and composition of positively charged ions; among which, Based on the measured energy of the positively charged ions, combined with the voltage of the first lens and the voltage inside the sidewall of the ionization element, the energy of the neutral atom is calculated according to the following conditional formula: E = E0 - C × e × (V2 - V1) In the formula, E is the energy of the neutral atom; E0 is the energy of the positively charged ion measured; V1 is the voltage of the first lens; V2 is the voltage inside the ionization element; C is a constant, which is related to the parameters and configuration of the focusing electrode, ionization element and lens assembly; and e is the amount of electron charge.

10. The neutral atom detection device according to claim 1, characterized in that, The turntable is configured to swing upwards or downwards to detect neutral atoms incident along the pitch direction of the detector within the satellite's orbital space.

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