Neutral atom detection device based on nested detection channel

Abstract

The invention discloses a neutral atom detection device based on a nested detection channel, and the device comprises a detector which comprises an ion deflection mechanism and an electrostatic analyzer, and the ion deflection mechanism comprises a plurality of deflection members and a plurality of ionization members which are coaxially arranged; a gap between the two deflection pieces forms a detection channel, and the multiple detection channels are annular detection view fields which are sequentially distributed at intervals from inside to outside so as to collect neutral atoms incident in a satellite operation orbit space; the plurality of ionization pieces are sequentially sleeved from inside to outside, and neutral atoms introduced into each detection channel correspondingly enter the ionization pieces at a grazing incidence angle; the electrostatic analyzer comprises a first electrode and a second electrode, a first passage is arranged between the first electrode and the second electrode, and the first passage deflects the positively charged ions entering through the plurality of detection channels; the rotary table is installed on the satellite platform, the rotary table is configured to be capable of rotating, and the detector is installed on the rotary table. The effective area of the nested detection channel is greatly increased.

Description

Technical Field

[0001] The present 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 Art

[0002] Charged ions and uncharged neutral atoms (ENA) are ubiquitous in deep space, including Earth's space, the interplanetary system, and other planetary regions of the solar system. Charged ions can become uncharged neutral atoms through charge exchange (accepting an electron). Uncharged neutral atoms can also become charged ions through charge exchange (losing an electron). The charge exchange process between charged ions and neutral atoms reflects the fundamental physical mechanism of energy transfer in space. Therefore, measuring information about charged ions and neutral atoms in space can be used to study fundamental physics problems of human interest, such as how low-energy particles are accelerated to high-energy particles and how the Sun influences the formation and dissipation of planetary atmospheres. Addressing these issues will help humanity understand the unknown and ensure 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. This allows them to be used to invert the state of distant plasma regions. Therefore, neutral atom detection is widely used as a remote sensing method in space environmental monitoring, achieving unique detection results. Currently, neutral atom detectors are being deployed on satellites such as the US space science satellites IMAGE and IBEX, the European Space Agency's Mars Express and JUICE, and China's Tianwen-1, to detect neutral atoms in space.

[0004] Currently, the common method for measuring neutral atoms is to first ionize them into charged ions, and then measure them using charged ion measurement methods. There are two main ionization methods: grazing incidence ionization plate and penetrating ultra-thin film. A typical representative of grazing incidence ionization plate neutral atom detectors is China's Tianwen-1 Mars Ion and Neutral Particle Analyzer (MINPA). MINPA integrates both ion and neutral atom detection functions, enabling the detection of lower-energy neutral atoms. The efficiency of neutral atom generation through the interaction of neutral atoms with the ionization plate is typically low (less than a few percent). A larger effective detection area of ​​the detector increases the detection sensitivity, making it more effective for detecting low-flux neutral atoms in the environment. However, existing neutral atom detectors (MINPAs) suffer from a small effective detection area, making them less suitable for low-flux neutral atom detection. Summary of the Invention

[0005] An embodiment of the present invention provides a neutral atom detection device based on a nested detection channel, comprising: a detector, which includes an ion deflection mechanism and an electrostatic analyzer; wherein the ion deflection mechanism includes a plurality of deflection members and a plurality of ionization members arranged coaxially; wherein the deflection member is a cylindrical sleeve, and the plurality of deflection members are sequentially arranged from the inside to the outside, and the gap between the two deflection members forms a detection channel, and the plurality of detection channels are circular detection fields spaced apart from each other from the inside to the outside, which are used to collect neutral atoms incident from the satellite orbit space and can shield charged particles incident from the satellite orbit space; the ionization member is a truncated cone-shaped sleeve, and the plurality of ionization members are sequentially arranged from the inside to the outside, and the neutral atoms introduced into each detection channel enter the ionization member at a corresponding grazing incidence angle, and are ionized into positively charged ions by the ionization member. an electrostatic analyzer comprising a first electrode and a second electrode, wherein a first path is provided between the first electrode and the second electrode, wherein the first path is used to deflect the positively charged ions entering through the plurality of detection channels, and perform energy analysis on the positively charged ions entering the first path by applying a voltage through the second electrode; a turntable mounted on a satellite platform, wherein the turntable is configured to be rotatable, and the detector is mounted on the turntable; wherein the ion deflection mechanism is configured to extend axially along a first direction to collect neutral atoms incident along a first direction in the satellite orbit space, and when the turntable rotates, the detector is driven to rotate to detect neutral atoms incident along a circumferential direction of the detector in the satellite orbit space; the axes of the plurality of detection channels are perpendicular to the axes of the first electrode and the second electrode.

[0006] Furthermore, the ionization element is configured to be gradually inclined along the axis of the detection channel, with the large end of the ionization element close to the exit end of the detection channel and the small end of the ionization element close to the electrostatic analyzer; the inclination angle formed by the side wall of the ionization element and the axis of the detection channel is set to 10°-15°.

[0007] Furthermore, the deflection member includes: a first deflection member, a second deflection member, a third deflection member and a fourth deflection member arranged in sequence from the inside to the outside, the gap between the first deflection member and the second deflection member forms a first detection channel, and the gap between the third deflection member and the fourth deflection member forms a second detection channel.

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

[0009] Furthermore, the voltage polarities between the first deflection element and the second deflection element are set to be opposite, the voltage polarities between the third deflection element and the fourth deflection element are set to be opposite, and the voltage polarities between the second deflection element and the third deflection element are set to be the same; The voltage outside the side wall of the ionization element is higher than the voltage inside the side wall.

[0010] Furthermore, the neutral atom detection device further comprises: a lens assembly located between the ion deflection mechanism and the electrostatic analyzer, the lens assembly comprising a first lens and a second lens, the first lens being located between the second lens and the electrostatic analyzer; A first hole is provided in the first lens, a second hole is provided in the second lens, and the second hole is connected to the first hole to form a second passage; The first lens and the second lens are both connected to a negative voltage to form an electric field distribution, which can accelerate and focus the positively charged ions entering the second path through the first detection channel and the second detection channel to enter the first path.

[0011] Furthermore, the ion deflection mechanism further comprises: The focusing electrode is used to converge the positively charged ions ionized in the first ionization element and the second ionization element to the second hole of the second lens. The focusing electrode is sleeved on the outside of the second ionization element, and the voltage of the focusing electrode is greater than the voltage outside the side wall of the second ionization element.

[0012] Furthermore, a protrusion is provided on the side of the focusing electrode close to the second lens, the protrusion is gradually inclined along the axis of the detection channel, and the protrusion gradually shrinks along the direction close to the second lens; wherein, the inclination angle formed by the protrusion and the axis of the detection channel is less than 60 degrees.

[0013] Furthermore, the neutral atom detection device further comprises: A time-of-flight system for generating a starting point electrical signal and an ending point electrical signal of positively charged ions output from the electrostatic analyzer within a fixed flight distance; The electronic processing unit is used to process the electrical signal output by the time-of-flight system to obtain the direction, energy and composition information of the positively charged ions; wherein, The energy of the neutral atom is calculated based on the measured energy of the positively charged ions, the voltage of the first lens, and the voltage inside the sidewall of the ionizer according to the following conditional equation; the conditional equation is as follows: E=E0-C×e×(V2-V1) Wherein, E is the energy of neutral atoms; E0 is the measured energy of positively charged ions; 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 charge of an electron.

[0014] Furthermore, the turntable is configured to be able to swing upward or downward so as to detect neutral atoms incident along the pitch direction of the detector in the satellite orbit space.

[0015] The above technical solution of the present invention has the following beneficial technical effects: In an embodiment of the present invention, each detection channel is a circular detection field of view, and multiple detection channels are nested detection channels spaced from the inside to the outside. When collecting neutral atoms incident along a first direction in the satellite orbit 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 the embodiment of the present invention is greatly increased, thereby improving the sensitivity of the detector and being more beneficial for detecting low-flux neutral atoms in the environment. In addition, the detector is installed on a turntable, and the 360-degree circumferential rotation of the turntable can collect neutral atoms incident along the circumference of the detector in the satellite orbit space, thereby expanding the detection range of the detector in the satellite orbit space. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the detection principle of the ion and neutral particle analyzer MINPA in the related art; Figure 2 is a schematic structural diagram of a neutral atom detection device based on nested detection channels according to a first embodiment of the present invention; Figure 3 is a schematic structural diagram of a neutral atom detection device based on nested detection channels according to a second embodiment of the present invention; Figure 4 is a schematic structural diagram of a neutral atom detection device based on nested detection channels according to a third embodiment of the present invention; Reference numerals: 1. First deflection plate; 2. Second deflection plate; 3. Ionization plate; 4. Toroidal analyzer; 5. Time of flight evaluation unit; 10. Ion deflection mechanism; 11. Shell; 12. First deflection member; 13. Second deflection member; 14. Third deflection member; 15. Fourth deflection member; 16. First ionization member; 17. Second ionization member; 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. Electronic processing unit. DETAILED DESCRIPTION

[0017] To make the objects, technical solutions and advantages of the present invention more clear, the present invention will be described in further detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present invention. In this article, terms such as first, second, and third are only used to distinguish one feature from another, and do not require or imply any order or relationship between these features.

[0018] A typical representative model of grazing incidence ionization plate neutral atom detector is China's Tianwen-1 Mars Ion and Neutral Particle Analyzer (MINPA). The detection principle of the analyzer MINPA is as follows: Figure 1 As shown, the analyzer MINPA integrates both ion and neutral atom detection functions, with a neutral atom detection energy range of 50 eV to 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 before striking the ionization plate 3 at grazing incidence. High voltage is applied to the first and second deflection plates 1 and 2 to form a deflection electric field, which deflects charged particles incident along with the neutral atoms to prevent interference with neutral atom detection. Neutral atoms strike the ionization plate at a 15° grazing incidence angle, partially ionizing them into positively charged ions. The ionized ions are deflected by the electric field created by the voltage applied by the lens and accelerated to the entrance of the toroidal analyzer 4. The toroidal analyzer 4 consists of two inner and outer hemispheres, forming a deflection electric field that only allows ions with a specific energy-to-charge ratio to pass through. By scanning the voltage in the inner hemisphere, the energy of the ionized ions can be analyzed. The ions emitted from the toroidal analyzer 4 enter the flight time evaluation unit 5, which measures the flight time of the ions within a fixed distance and determines the composition of the ions, which corresponds to the composition information of the neutral atoms. Figure 1 The detection field of neutral atoms of the analyzer MINPA is 16 detection windows distributed in a 360° circumferential direction. The detection field of each detection window is 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-flux neutral atoms.

[0019] In view of this, an embodiment of the present invention provides a neutral atom detection device based on a nested detection channel, such as Figure 2-4 As shown, it 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 a plurality of deflection members and a plurality of ionization members coaxially arranged; wherein the deflection member is a cylindrical sleeve, and the plurality of deflection members are sequentially arranged from the inside to the outside, and the gap between the two deflection members forms a detection channel, and the plurality of detection channels are circular detection fields spaced sequentially from the inside to the outside, which are used to collect neutral atoms incident from the satellite orbit space and can shield charged particles incident from the satellite orbit space; the ionization member is a truncated cone-shaped sleeve, and the plurality of ionization members are sequentially arranged from the inside to the outside, and the neutral atoms introduced into each detection channel enter the ionization member at a corresponding grazing incidence angle, and are ionized into positively charged ions by the ionization member; the electrostatic analyzer 30 includes a first electrode 31 and a second electrode 32 coaxially arranged and sequentially distributed from the outside to the inside, and the first electrode 31 and the second electrode 32 are arc plates shaped structure, and there is a first path between the first electrode 31 and the second electrode 32, the first path is used to deflect the positively charged ions entering through the multiple detection channels, and perform energy analysis on the positively charged ions entering the first path by the voltage applied by the second electrode 32; a turntable 40, which is installed on the satellite platform, the turntable 40 is configured to be able to rotate, and the detector is installed on the turntable 40; the ion deflection mechanism is configured to extend axially along the first direction to collect neutral atoms incident along the first direction in the satellite orbit space, and when the turntable 40 rotates, it drives the detector to rotate to realize the detection of neutral atoms incident along the circumference of the detector in the satellite orbit space; wherein, 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.

[0020] Specifically, the ion deflection mechanism 10 may further include a housing 11, wherein a plurality of coaxially arranged deflection elements and a plurality of ionization elements may be installed in the housing 11, and an insulating polyimide material ( Figure 3 and Figure 4), which is used to support and isolate various components. The shell 11 can be set to be grounded; the deflection member is, for example, a deflection electrode. The deflection member can be set to a cylindrical sleeve. The gap between the two deflection members forms a detection channel. When voltages of opposite polarity are applied to the two deflection members, a circular electric field perpendicular to the deflection member can be formed in the detection channel to introduce neutral atoms incident from the satellite orbit space, and deflect charged particles incident with the neutral atoms so that the charged particles cannot pass through the detection channel. The introduced neutral atoms hit the ionization member at a grazing incidence angle of 15 degrees. Each ionization member corresponds to a circular detection channel. The ionization member is a truncated cone-shaped sleeve. The inner wall of the ionization member is a smooth inclined surface. 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 sheet structures, the arc diameter of the first electrode 31 is larger than the arc diameter of the second electrode 32, and the arc sheet structure has an end face set to 1 / 4 circle, that is, the center angle of the arc sheet structure is 90 degrees. The positively charged ions passing through multiple detection channels converge and enter the first path between the first electrode 31 and the second electrode 32 of the electrostatic analyzer 30, and the voltage applied by the second electrode 32 is used to perform energy analysis on the positively charged ions entering the first path; the turntable 40 is configured to be rotatable, for example, the turntable 40 may be provided with a driven wheel, a driving wheel and a driving motor, the driving wheel may be installed on the output shaft of the driving motor, and the driven wheel may be installed on the rotating shaft of the turntable 40, the driving motor drives the driving wheel, and the meshing transmission of the driving wheel and the driven wheel drives the turntable 40 to rotate, thereby driving the detector installed on the turntable 40 to rotate circumferentially; the ion deflection mechanism 10 may be arranged on one side of the electrostatic analyzer 30, and the axis of the detection channel is aligned with the first electrode 31 and the second electrode 32 The axis of the detection channel is roughly perpendicular to the axis of the turntable 40. Through the rotation of the turntable 40, the neutral atoms incident along the circumference of the detector in the satellite orbit space can be detected; wherein, the first direction can be, for example, any direction in the satellite orbit space, each detection channel is a circular detection field of view, and multiple detection channels are nested detection channels spaced from the inside to the outside. When collecting neutral atoms incident along the first direction in the satellite orbit space, the effective area of ​​each detection channel is the area of ​​the entire circular ring. Compared with the detection window being a plurality of fan-shaped holes in the circumferential direction, the effective area of ​​the nested detection channel in the embodiment of the present invention is greatly increased, so that the sensitivity of the detector is improved, which is more beneficial to the detection of low-flux neutral atoms in the environment, and the detector is installed on the turntable. Through the 360-degree circumferential rotation of the turntable, the neutral atoms incident along the circumference of the detector in the satellite orbit space can be collected, thereby expanding the detection range of the detector in the satellite orbit space.

[0021] Among them, a commonly used factor used to consider the detection sensitivity in particle detection is the geometric factor, which is the detection area × detection solid angle. The geometric factor represents the comprehensive amount of the detection instrument's area and angle acceptance. If the smallest diameter of the inner ring detection channel is the same as the above Figure 1 The diameter of the circle where the channel is formed between the first deflection plate 1 and the second deflection plate 2 of the MINPA detector is the same, and the width of the channel slits of the two are also the same. Then the geometric factor of the inner ring detection channel of the embodiment of the present application is the above Figure 1 The geometric factor of the detection channel of the outer ring is greater than 16 times. In general, the effective area of ​​the detection channel of the embodiment of the present invention is increased by more than 32 times.

[0022] In an embodiment of the present invention, the neutral atom detection device may further include: a time-of-flight system 50 for generating starting and ending electrical signals within a fixed flight distance based on the ions output from the electrostatic analyzer 30; and an electronic processing unit 60 for processing the electrical signals output by the time-of-flight system 50 to obtain information on the direction, energy, and composition of the positively charged ions and neutral atoms. The electronic processing unit 60 may be mounted within a housing, the electrostatic analyzer 30 and the time-of-flight system 50 may be mounted on the top surface of the housing, the housing 11 of the ion deflection mechanism 10 may also be mounted on the housing, and the housing may be mounted on the turntable 40. Figure 2 The direction of the arrow shown in the figure is the direction of the electrical signal output by the time-of-flight system 50 to the electronic processing unit 60. The first electrode 31 and the second electrode 32 of the electrostatic analyzer 30 are coaxially arranged arc-shaped sheet structures. The angle between the centers of the arc-shaped sheet structures is 90 degrees, that is, the arc bottom surfaces of the first electrode 31 and the second electrode 32 are parallel to the top surface of the turntable 40. The ion deflection mechanism 10 can be arranged on one side of the electrostatic analyzer 30, and the time-of-flight system 50 can be arranged on the other side of the electrostatic analyzer 30. The flight path for positively charged ions to enter the time-of-flight system 50 is located on the same arc as the first path, thereby shortening the flow path of the positively charged ions. Figure 2 The dotted line in the figure is the incident path of the neutral atom, and the dotted line is the trajectory of the positively charged ions after ionization. Figure 2 The direction of the arrow shown in FIG is the direction in which the electrical signal output by the time-of-flight system 50 is sent to the electronic processing unit 60 .

[0023] In some embodiments, the ionization element is configured to gradually tilt along the axis of the detection channel, with the larger end of the ionization element proximate the emission end of the detection channel and the smaller end of the ionization element proximate the electrostatic analyzer 30. The angle formed by the sidewall of the ionization element and the axis of the detection channel is set to 10°-15°. In this way, the introduced neutral atoms strike the inner sidewall of the ionization element at a grazing incidence angle. The inner wall of the ionization element is a smooth, inclined surface coated with an aluminum oxide film, which increases the contact area with the introduced neutral atoms, thereby ionizing more neutral atoms into positively charged ions.

[0024] In some embodiments, the deflection member includes: a first deflection member 12, a second deflection member 13, a third deflection member 14 and a fourth deflection member 15 which are sequentially arranged from the inside out. The gap between the first deflection member 12 and the second deflection member 13 forms a first detection channel 21, and the gap between the third deflection member 14 and the fourth deflection member 15 forms a second detection channel 22. The first deflection member 12 can be filled with an insulating polyimide material, and the space between the second deflection member 13 and the third deflection member 14 can also be filled with an insulating polyimide material. The space between the fourth deflection member 15 and the shell 11 can also be filled with an insulating polyimide material. The various parts in the shell 11 can be supported by insulating materials and then fixed to the shell 11 by insulating materials. Therefore, a small amount of polyimide material can be filled between the first deflection member 12 and the second deflection member 13 to achieve support for the first deflection member 12; the first deflection member 12 and the second deflection member 13 are subjected to insulation. By applying a voltage of opposite polarity, a circular electric field perpendicular to the deflection element can be formed in the first detection channel 21, which can introduce neutral atoms incident from the satellite orbit space and deflect charged particles incident with the neutral atoms, so that the charged particles cannot pass through the detection channel; similarly, a second detection channel 22 can be formed between the third deflection element 14 and the fourth deflection element 15, wherein, in order to avoid the high electric field formed between electrodes of opposite polarity and cause high voltage discharge, the voltage polarity between the second deflection element 13 and the third deflection element 14 can be set to the same.

[0025] In some embodiments, the ionization element includes a first ionization element 16 and a second ionization element 17 which are sequentially arranged from the inside to the outside, the inner diameter of the large end of the first ionization element 16 is larger than the outer diameter of the second deflection element 13, and the inner diameter of the large end of the second ionization element 17 is larger than the outer diameter of the fourth deflection element 15; wherein, the 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; the 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 ionization element 16 and the second ionization element 17 as truncated cone-shaped sleeves, and the inner diameter of the large end of the first ionization element 16 is larger than the outer diameter of the second deflection element 13, and the inner diameter of the large end of the second ionization element 17 is larger than the outer diameter of the fourth deflection element 15, it is beneficial for neutral atoms to enter the ionization element at a grazing incidence angle, and the contact area with the neutral atoms is increased. Combined with setting the external voltage of the side wall of the ionization element to be higher than the internal voltage of the side wall, the motion trajectory of the positively charged ions after ionization is adjusted, so that the positively charged ions after ionization can be accelerated and focused in a preset direction.

[0026] In some embodiments, the neutral atom detection device further includes: a lens assembly, which is located between the ion deflection mechanism 10 and the electrostatic analyzer 30, the lens assembly including a first lens 18 and a second lens 19, the first lens 18 being located between the second lens 19 and the electrostatic analyzer 30; a first through hole is provided in the first lens 18, and a second through hole is provided in the second lens 19, the second hole and the first hole are connected to form a second path; the first lens 18 and the second lens 19 are both connected to a negative voltage to form an electric field distribution, and the electric field distribution can accelerate and focus the positively charged ions entering the second path through the first detection channel 21 and the second detection channel 22 to enter the first path. Specifically, the lens assembly can be installed in the shell 11, and the first lens 18 and the second lens 19 can be, for example, cylinders made of metal. The first lens 18 and the second lens 19 are both connected to a negative voltage to form an electric field distribution. The neutral atoms introduced through the first detection channel 21 and the second detection channel 22 are ionized to become positively charged ions, which can pass through the second lens 19 and the first lens 18 in turn and then enter 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 converged before entering the electrostatic analyzer 30.

[0027] In some embodiments, the ion deflection mechanism 10 further includes a focusing electrode 20 for converging positively charged ions ionized in the first ionization element 16 and the second ionization element 17 to the second aperture of the second lens 19. The focusing electrode 20 is disposed outside the second ionization element 17, and the voltage of the focusing electrode 20 is greater than the voltage outside the sidewall of the second ionization element 17. An insulating polyimide material may be filled between the focusing electrode 20 and the housing 11 to support the focusing electrode 20. An insulating polyimide material may also be filled between the focusing electrode 20 and the second ionization element 17 to support the second ionization element 17. A small amount of polyimide material may be filled between the first ionization element 16 and the second ionization element 17 to support the first ionization element 16. By providing the focusing electrode 20 and setting the voltage of the focusing electrode 20 to be greater than the voltage outside the sidewall of the ionization element, the positively charged ions ionized by the generated electric field are accelerated and effectively converged before entering the electrostatic analyzer 30.

[0028] In some embodiments, the focusing electrode 20 has a protrusion on the side proximal to the second lens 19. The protrusion is gradually inclined along the axis of the detection channel and gradually shrinks in the direction approaching the second lens 19; the inclination angle formed by the protrusion and the axis of the detection channel is less than 60 degrees. By configuring the protrusion of the focusing electrode 20 as a closed-end structure, combining the voltage of the focusing electrode 20 with a voltage greater than the voltage outside the sidewall of the ionization element, and the voltage of the second lens 19 being negative, the positively charged ions ionized by the two nested ionization elements can be accelerated and effectively converged, flowing into the second lens 19 along a predetermined motion trajectory.

[0029] In some embodiments, the energy of the neutral atom is calculated based on the measured energy of the positively charged ions, the voltage of the first lens 18, and the voltage inside the sidewall of the ionization element according to the following conditional equation; the conditional equation is as follows: E=E0-C×e×(V2-V1) Wherein, 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 experiments; e is the charge of an electron.

[0030] 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 velocity information of the positively charged ions. Combined with the energy of the positively charged ions measured by the electrostatic analyzer 30, the energy of the neutral atoms can be calculated using the above-mentioned conditional equation. The measured composition of the positively charged ions corresponds to the composition of the neutral atoms. This conditional equation simplifies the calculation of the energy of the neutral atoms and provides a highly accurate result.

[0031] In some embodiments, the turntable 40 is configured to swing upward or downward to detect neutral atoms incident along the detector's pitch direction within the satellite's orbital space. A drive assembly may be provided on the bottom surface of the turntable 40 to drive the turntable 40 to swing upward or downward relative to the satellite platform, thereby enabling detection of neutral atoms incident along the detector's pitch direction within the satellite's orbital space over a wider angular range.

[0032] The specific implementation process of the present invention is described as follows: The neutral atom detection device provided in an embodiment of the present invention has two annular neutral atom detection channels, one inside and one outside. For example, the inner channel is the first detection channel 21. Incident neutral atoms first pass through the first detection channel 21, which is located between the first deflector 12 and the second deflector 13. Voltages of opposite polarity are applied to the first and second deflector 12, 13, respectively. This creates an electric field perpendicular to the deflector annular surface, deflecting charged particles incident with the neutral atoms, preventing them from passing through the first detection channel 21. Furthermore, the first detection channel 21 can restrict the direction of incident neutral atoms, limiting the angle of incidence to approximately 15°. Neutral atoms passing through the first detection channel 21 strike the first ionizer 16, where the surface normal of the first ionizer 16 forms an angle of approximately 10-15° with the surface normal of the first deflector 12. The inner sidewall of the first ionizer 16 is a highly smooth, beveled surface, which can be coated with an aluminum oxide film. Neutral atoms are incident on the surface of the first ionization element 16 at a grazing incidence angle, interacting with the aluminum oxide film. Some of the neutral atoms are ionized into positively charged ions. The ionized positively charged ions converge to the entrance of the second lens under the combined action of the inner voltage, outer voltage, and voltage of the focusing electrode 20 of the first ionization element 16. The inner voltages of the first ionization element 16 and the second ionization element 17 are the same, which enables the detection of neutral atoms in the same energy range. The outer voltages of the first ionization element 16 and the second ionization element 17 are higher than the 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 a cylindrical structure with a closed-end design, and cooperates with the negative voltage of the second lens 19 to achieve effective convergence of positively charged ions in the case of two nested ionization elements.

[0033] The outer ring is the second detection channel 22, and the detection principle of the incident neutral atoms is similar to that of the inner ring.

[0034] The first lens 18 and the second lens 19 are respectively circular plates made of metal, with the center of the circular plates hollowed out to form a channel for positively charged ions. Negative voltage is applied to both the first lens 18 and the second lens 19, forming an electric field distribution that accelerates and focuses the positively charged ions. The positively charged ions ionized in the inner and outer annular detection channels can be accelerated and focused by the voltages of the first lens 18 and the second lens 19, respectively, and then enter the channel of the electrostatic analyzer 30. A negative voltage is applied to the second electrode 32 of the electrostatic analyzer 30, and the first electrode 31 is grounded. A deflection electric field is formed between the first electrode 31 and the second electrode 32 to deflect the incident positively charged ions. The energy of the positively charged ions passing through the first channel of the electrostatic analyzer 30 is related to the voltage applied to the second electrode 32. The positively charged ions passing through the first channel of the electrostatic analyzer 30 enter the time-of-flight system 50. Positively charged ions penetrate a thin film at the entrance of the TOF system, generating secondary electrons through interaction with the film. These secondary electrons are collected as the ion's starting electrical signal within the TOF system. The positively charged ions continue their flight and penetrate another thin film at the exit of the TOF system, generating secondary electrons through interaction with the film. These secondary electrons are collected as the ion's ending electrical signal within the TOF system. The time difference between the ending electrical signal and the starting electrical signal is measured, representing the flight time of the positively charged ions within a fixed distance. This information is then used to determine the ion's velocity. Combined with the positive ion energy information measured by the electrostatic analyzer 30, the mass (composition) of the positively charged ions can be determined. The composition of the positively charged ions corresponds to the composition of the neutral atoms. The neutral atom energy E is calculated by combining the measured positive ion energy E0 with the voltage V1 of the first lens 18 and the voltage V2 inside the ionizer: E = E0 - C × e × (V2 - V1). Wherein C and e are both constants, C is related to the parameters and configurations 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 experiments, and e is the charge of an electron.

[0035] For example, when the energy E of the neutral atom to be detected is 1 keV, the voltage difference between the outer voltage and the inner voltage of the first ionization element 16 and the second ionization element 17 is set to about 400 V, the voltage of the focusing electrode 20 is greater than the outer voltage of the ionization element, and the voltage difference between the two does not exceed 3000 V, forming a deflection electric field. The direction of the electric field finally formed points to the entrance of the second lens 19 along the movement trajectory of the positively charged ions. Among them, the voltages applied to each component are as follows: the voltage of the first deflection element 12 is -5000V; the voltage of the second deflection element 13 is +5000V; the voltage of the third deflection element 14 is +5000V; the voltage of the fourth deflection element 15 is -5000V; the inner voltage of the first ionization element 16 is the same as the inner voltage of the second ionization element 17, which is +1200V; the outer voltage of the first ionization element 16 is the same as the outer voltage of the second ionization element 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.

[0036] The advantages of the technical solution of the present invention are: (1) Compared with existing detection instruments, the neutral atom detection device of the embodiment of the present invention expands the detection channel from a fan-shaped field of view to two annular detection fields of view with minimized resources, thereby increasing the effective detection area by more than 32 times, greatly improving the detection sensitivity of the detector, and facilitating the detection of low-flux neutral atoms; and the annular detection field of view can also significantly increase the effective detection area by increasing the number of nested layers.

[0037] (2) Neutral atom detection is performed in a specific direction in the satellite orbit space. The effective detection area of ​​the neutral atom detection device in the embodiment of the present invention has been greatly improved. In order to expand the detection range of the detector in the satellite orbit 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 can realize the detection of neutral atoms in a wider range.

[0038] It should be understood that the above-described specific embodiments of the present invention are merely illustrative or illustrative of the principles of the present invention and do not constitute limitations of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present invention should be included within the scope of protection of the present invention. In addition, the appended claims are intended to cover all variations and modifications that fall within the scope and metes and bounds of the appended claims, or equivalents thereof.

Claims

1. A neutral atom detection device based on nested detection channels, characterized in that: include: A detector comprising an ion deflection mechanism and an electrostatic analyzer; wherein, The ion deflection mechanism includes a plurality of deflection elements and a plurality of ionization elements arranged coaxially; wherein, The deflector is a cylindrical sleeve, and multiple deflector members are arranged in sequence from the inside out. The gap between the two deflector members forms a detection channel. The multiple detection channels are circular detection fields that are spaced from the inside out and are used to collect neutral atoms incident from the satellite orbit space and can shield charged particles incident from the satellite orbit space. The ionization element is a truncated cone-shaped sleeve, and multiple ionization elements are arranged in sequence from the inside out. Neutral atoms introduced into each detection channel enter the ionization element at a corresponding grazing incidence angle and are ionized into positively charged ions by the ionization element. The electrostatic analyzer includes a first electrode and a second electrode coaxially arranged and sequentially distributed from the outside to the inside. The first electrode and the second electrode are circular arc sheet structures, and a first passage is provided between the first electrode and the second electrode. The first passage is used to deflect positively charged ions entering through the plurality of detection channels, and the voltage applied by the second electrode is used to perform energy analysis on the positively charged ions entering the first passage. A turntable is mounted on the satellite platform, the turntable is configured to be rotatable, and the detector is mounted on the turntable; wherein, The ion deflection mechanism is configured to extend axially in a first direction to collect neutral atoms incident along the first direction in the satellite orbital space. When the turntable rotates, the detector is driven to rotate to detect neutral atoms incident along a circumferential direction of the detector in the satellite 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 ionization element is configured to be gradually inclined along the axis of the detection channel, with the large end of the ionization element close to the exit end of the detection channel and the small end of the ionization element close to the electrostatic analyzer; The inclination angle formed by the side wall of the ionization component 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 deflecting member comprises: The first deflecting member, the second deflecting member, the third deflecting member and the fourth deflecting member are sequentially arranged from the inside out. The gap between the first deflecting member and the second deflecting member forms a first detection channel, and the gap between the third deflecting member and the fourth deflecting member forms a 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 which are sequentially sleeved from the inside out. The inner diameter of the large end of the first ionization element is larger than the outer diameter of the second deflection element. The inner diameter of the large end of the second ionization element is larger than the outer diameter of the fourth deflection 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; The 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 polarities between the first deflection element and the second deflection element are set to be opposite, the voltage polarities between the third deflection element and the fourth deflection element are set to be opposite, and the voltage polarities between the second deflection element and the third deflection element are set to be the same; The voltage outside the side wall of the ionization element is higher than the voltage inside the side wall.

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

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

8. The neutral atom detection device according to claim 7, characterized in that: A convex portion is provided on one side of the focusing electrode close to the second lens, the convex portion is gradually inclined along the axis of the detection channel, and the convex portion gradually shrinks along the direction close to the second lens; wherein, An inclination angle formed by 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: A time-of-flight system for generating a starting point electrical signal and an ending point electrical signal of positively charged ions output from the electrostatic analyzer within a fixed flight distance; The electronic processing unit is used to process the electrical signal output by the time-of-flight system to obtain the direction, energy and composition information of the positively charged ions; wherein, The energy of the neutral atom is calculated based on the measured energy of the positively charged ions, the voltage of the first lens, and the voltage inside the sidewall of the ionizer according to the following conditional equation; the conditional equation is as follows: E=E0-C×e×(V2-V1) Wherein, 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; 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 charge of an electron.

10. The neutral atom detection device according to claim 1, characterized in that: The turntable is configured to be able to swing upward or downward so as to detect neutral atoms incident along the pitch direction of the detector in the satellite orbit space.

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