Neutral gas ionization source mechanism with multiple channels and detection device

Abstract

The application discloses a neutral gas ionization source mechanism with multiple channels and a detection device. The neutral gas ionization source mechanism comprises multiple grid electrodes connected and enclosed to form a polyhedral structure. The inner cavity of the polyhedral structure constitutes an ionization area. Corresponding voltages are applied to the multiple grid electrodes, so that an ion storage potential well is formed in the central region of the ionization area. The grid electrode structure has oppositely arranged first and second side surfaces and a connecting peripheral surface. One side of the peripheral surface is provided with a gating grid electrode. By changing the voltage of the gating grid electrode, the ions after ionization enter a time-of-flight measurement system through the gating grid electrode. Two electron beam emission mechanisms are arranged on opposite sides of the grid electrode structure. Multiple detection channels are located on the outer side of the peripheral surface. One of the multiple detection channels is arranged on the outer side of the opposite side of the gating grid electrode. The application can meet the requirements of low-density, high-sensitivity detection of neutral particles and long-time operation.

Description

Technical Field

[0001] This invention relates to the technical field of space environment detection, and in particular to a neutral gas ionization source mechanism and detection device with multiple channels. Background Technology

[0002] Neutral gases are an important component of Earth's atmosphere. They are also widely present in outer space and around other celestial bodies, making them crucial for deep space exploration and understanding stellar evolution and habitability. Conventional methods for neutral gas detection include remote sensing and in-situ detection. In-situ detection, with its high precision, has always played a vital role in neutral gas detection. Most domestic and international Earth and deep space exploration missions are equipped with in-situ neutral gas detection payloads.

[0003] In existing in-situ detection techniques for neutral gases, there is only one neutral gas injection channel. This results in a relatively small flow rate of neutral gas entering the ionization space. This is especially problematic when detecting celestial bodies with extremely low neutral gas density, such as the Moon and asteroid surfaces, making it difficult to meet the requirements for low-density, high-sensitivity measurements. Summary of the Invention

[0004] The purpose of this invention is to provide a neutral gas ionization source mechanism and detection device with multiple channels.

[0005] A first aspect of the present invention provides a multi-channel neutral gas ionization source mechanism, including a grid electrode structure, an electron beam emission mechanism, and multiple detection channels. The grid electrode structure includes multiple grid electrodes connected and enclosing a polyhedral structure. The inner cavity of the polyhedral structure constitutes an ionization region. Applying a corresponding voltage to the multiple grid electrodes causes an ion storage potential well to be formed in the central region of the ionization region for storing ionized ions. The grid electrode structure has a first side and a second side arranged opposite to each other, and a peripheral surface connecting the first side and the second side. One side of the peripheral surface is provided with a gated grid electrode. By changing the voltage of the gated grid electrode, ionized ions are allowed to pass through the gate. The gated grid electrode enters the time-of-flight measurement system; the electron beam emitting mechanism includes two electron beam emitting mechanisms, which are respectively disposed on opposite sides of the gated grid electrode structure. The electron beam emitting mechanism is used to emit electron beams, which enter the ionization region from the first side and the second side respectively, so as to ionize neutral particles incident through multiple detection channels in the ionization region; the multiple detection channels are located on the outer side of the circumferential surface, and the multiple detection channels are used to deflect charged particles incident in the spacecraft's orbital space, so that the incident neutral particles enter the ionization region through the side of the circumferential surface, and one of the multiple detection channels is disposed on the outer side of the opposite side of the gated grid electrode.

[0006] Furthermore, the grid electrode structure includes multiple channel inlet grid electrodes, two electron beam inlet grid electrodes, and the gated grid electrode. Each channel inlet grid electrode and the gated grid electrode are respectively located on one side of the circumferential surface, and each channel inlet grid electrode is located between each detection channel and the ionization region. The two electron beam inlet grid electrodes are respectively disposed on the first side and the second side, and the electron beam inlet grid electrode is located between the electron beam emission mechanism and the ionization region. A corresponding set negative voltage is applied to the multiple channel inlet grid electrodes, the electron beam inlet grid electrodes, and the gated grid electrode, so that an ion storage potential trap is formed in the central region of the ionization region to achieve the binding of ionized ions.

[0007] Furthermore, the plurality of detection channels include a first detection channel, a second detection channel, and a third detection channel. The first detection channel and the gated grid electrode are respectively disposed on both sides of the grid electrode structure along a first direction. The second detection channel and the third detection channel are respectively disposed on both sides of the grid electrode structure along a second direction. Two electron beam emission mechanisms are disposed opposite to each other on both sides of the grid electrode structure along a third direction. The first direction, the second direction, and the third direction are approximately perpendicular to each other.

[0008] Further, the channel inlet grid electrode includes a first channel inlet grid electrode, a second channel inlet grid electrode, and a third channel inlet grid electrode disposed opposite to each other, wherein the first channel inlet grid electrode is disposed opposite to the gated grid electrode. If a first set voltage is applied to the first channel inlet gate electrode and the gated gate electrode, a second set voltage is applied to the second channel inlet gate electrode and the third channel inlet gate electrode, and a third set voltage is applied to the two electron beam inlet gate electrodes arranged opposite to each other, an ion storage potential trap is formed in the central region of the ionization region to bind the ionized ions. The absolute value of the third set voltage is greater than the absolute value of the first set voltage, and the absolute value of the first set voltage is greater than the absolute value of the second set voltage.

[0009] Furthermore, if a fourth set voltage is applied to the gated grid electrode, causing ionized ions to enter the time-of-flight measurement system via the gated grid electrode; wherein the absolute value of the fourth set voltage is greater than the absolute value of the third set voltage; The third set voltage has a value of -5V to -1V, and the fourth set voltage has a value of -600V to -100V.

[0010] Furthermore, the electron beam emitting mechanism includes an emission source and a storage lens electrode assembly, wherein, The emission source is used to generate an emitted electron beam, and the storage lens electrode group is used to modulate the trajectory and focusing characteristics of the emitted electron beam; the two electron beam emission mechanisms are symmetrically arranged with respect to the ionization region, and the two emission sources adopt a time-sharing intermittent working system to extend the working time of the emission sources.

[0011] Furthermore, by applying an appropriate voltage to the storage lens electrode group located on both sides of the ionization region, the trajectory and focusing characteristics of the emitted electron beam are modulated, thereby forming a space charge effect of the electron beam in the ionization region, so as to reduce the potential of the central region of the ionization region.

[0012] Furthermore, the detection channel is configured to consist of a gap formed between two oppositely arranged deflection plates, and the voltage polarity between the two deflection plates is set to be opposite.

[0013] Furthermore, the detection channel is suitable for neutral particle densities in the spacecraft's orbital space ranging from 1 to 10. 10 cm -3 .

[0014] A second aspect of the present invention provides a detection device, comprising: the aforementioned neutral gas ionization source mechanism and a time-of-flight measurement system, wherein ionized ions output from the neutral gas ionization source mechanism enter the time-of-flight measurement system via a gated grid electrode, and the time-of-flight measurement system is used to detect the composition resolution and flux intensity of the ionized ions, so as to obtain the density and composition information of neutral particles in the spacecraft's orbital space incident through the detection channel.

[0015] The above-described technical solution of the present invention has the following beneficial technical effects: The neutral gas ionization source mechanism provided in this embodiment of the invention has multiple detection channels and integrates two backup electron beam emission mechanisms. The grid electrode structure formed by connecting and enclosing multiple grid electrodes is designed as a polyhedral structure. The multiple detection channels and the two electron beam emission mechanisms correspond to different sides of the grid electrode structure. By flexibly controlling the corresponding voltage of the grid electrodes on each side of the grid electrode structure, an ion storage potential trap is formed in the central region of the ionization region. This provides high flexibility in potential control and makes the overall structure of the neutral gas ionization source mechanism compact and rationally distributed. It can meet the low-density and high-sensitivity measurement requirements for detecting celestial bodies with extremely low neutral gas density, such as the moon and asteroid surfaces, and can also meet the requirements for long-term operation. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of a neutral gas ionization and detection instrument in related technologies; Figure 2This is a schematic diagram of a multi-channel neutral gas ionization source mechanism according to the first embodiment of the present invention; Figure 3 This is a schematic diagram of a multi-channel neutral gas ionization source mechanism according to a second embodiment of the present invention; Figure 4 This is a schematic diagram of a multi-channel neutral gas ionization source mechanism according to a third embodiment of the present invention; Figure 5 This is a schematic diagram of a multi-channel neutral gas ionization source mechanism according to a fourth embodiment of the present invention. Figure 6 A schematic diagram of the potential distribution of the ionization region in the YZ plane is shown. Figure 7 This is a schematic diagram showing the change of Ar+ density over time in the central region of the ionization zone under conditions where there is no ion storage potential trap. Figure 8 This is a schematic diagram showing the change of Ar+ density over time in the central region of the ionization region under the condition of an ion storage potential trap. Figure 9 This is a schematic diagram of the detection device according to the fifth embodiment of the present invention; Figure label: 1. Ionization source; 2. First drift region; 3. Ion reflection region; 4. Second drift region; 5. Detection assembly; 101. Filament; 102. Upper electrode assembly; 103. First electrode; 104. Second electrode; 105. Lower electrode assembly; 20. Neutral gas ionization source mechanism; 21. Gated grid electrode; 22. Electron beam inlet grid electrode; 23. First detection channel; 24. Second detection channel; 25. Third detection channel; 26. First channel inlet grid electrode; 27. Second channel inlet grid electrode; 28. Third channel inlet grid electrode; 29. ​​Emission source; 30. Storage lens electrode group; 31. Deflection plate; 40. Time-of-flight measurement system. Detailed Implementation

[0017] 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.

[0018] In related technologies, a neutral gas ionization and detection instrument, such as Figure 1As shown in the cross-sectional view, the device may include: an ionization source 1 and a time-of-flight system. The time-of-flight system may include a first drift region 2, an ion reflection region 3, a second drift region 4, and a detection component 5. The gray arrows represent the flow direction of the neutral gas stream, and the red arrows represent the electron beam. That is, the neutral gas stream enters from the left window and enters the ionization region, which is the space between the first electrode 103 and the second electrode 104 (i.e., Figure 1 Within the area defined by the two vertical dashed lines, filament 101 is positioned perpendicular to the neutral gas flow. A filament 101 is positioned above the ionization region, emitting an electron beam (red arrow) to ionize the incident neutral gas, forming low-energy ions. Applying a negative extraction voltage to the first electrode 103 on the right side can pull the ions out of the ionization region and into the subsequent time-of-flight system. If a potential well is formed within the ionization region to store the ionized ions, the voltages of the upper electrode group 102, lower electrode group 105, first electrode 103, and second electrode 104 need to be controlled to form the potential well.

[0019] Therefore, Figure 1 The ionization source shown may have the following defects and deficiencies: (1) The ionization source design adopts a single filament ionization scheme. The working life of the filament is limited. Especially in the high current working scenario, the filament life will be greatly reduced. Therefore, the single filament scheme is difficult to meet the requirements of long-term operation of the ionization source; (2) The neutral gas injection channel of the ionization source is one. The flow rate of neutral gas entering the ionization region is relatively small. Especially when detecting celestial bodies with extremely low neutral gas density, such as the moon and asteroid surfaces, it is difficult to meet the measurement requirements of low density and high sensitivity; (3) The potential trap in the ionization region is achieved by relying on the voltage control of the upper and lower electrode groups plus the first and second electrodes on the left and right sides. The flexibility of potential control is not high enough.

[0020] Therefore, embodiments of the present invention provide a neutral gas ionization source mechanism with multiple channels, referencing... Figures 2-5The system includes a grid electrode structure, an electron beam emission mechanism, and multiple detection channels. The grid electrode structure comprises multiple grid electrodes connected and enclosing a polyhedral structure. The interior of the polyhedral structure constitutes an ionization region. Applying a corresponding voltage to the multiple grid electrodes creates an ion storage potential well in the central region of the ionization region for storing ionized ions. The grid electrode structure has a first side and a second side arranged opposite to each other, and a peripheral surface connecting the first side and the second side. One side of the peripheral surface is equipped with a gated grid electrode 21. By changing the voltage of the gated grid electrode 21, ionized ions enter the time-of-flight measurement system through the gated grid electrode 21. The electron beam emission... The mechanism includes two electron beam emitting mechanisms, which are respectively disposed on opposite sides of the gated grid electrode structure. The electron beam emitting mechanisms are used to emit electron beams, which enter the ionization region from the first side and the second side, respectively, to ionize neutral particles incident through multiple detection channels in the ionization region. The multiple detection channels are located on the outer side of the circumferential surface. The multiple detection channels are used to deflect charged particles incident from the spacecraft's orbital space, so that the incident neutral particles enter the ionization region through the side of the circumferential surface. One of the multiple detection channels is disposed on the outer side of the opposite side of the gated grid electrode.

[0021] Specifically, each grid electrode can be designed as a sheet structure. For example, if there are six grid electrodes, each pair can be arranged opposite and parallel to each other, spaced apart in the vertical, horizontal, or front-back directions. The six grid electrodes are then connected sequentially and enclosed to form a cuboid structure, with the inner cavity of the cuboid structure constituting the ionization region. Appropriate voltages are applied to each grid electrode, and by flexibly adjusting the voltage of each grid electrode, an ion storage potential well is formed in the central region of the ionization region. That is, the potential is high near each grid electrode, resulting in an ion storage potential well with a high potential around the perimeter and a low potential in the center. This is beneficial for confining ionized ions and storing them. The electron beam emission mechanism can be located on opposite sides of the grid electrode structure in the vertical direction. The emitted electron beam passes through the grid electrodes located on the first and second sides and enters the ionization region. The electron beam ionizes the incident neutral particles in the ionization region, yielding ionized ions. The two electron beam emission mechanisms can operate intermittently in shifts, forming a backup for each other and increasing the service life of the ionization source mechanism. Multiple detection channels are located on the outer periphery of the grid electrode structure, for example, on the left, right and front, and back directions of the cuboid structure. Neutral particles incident through multiple detection channels pass through the grid electrodes located on the left, right and front, and back sides of the cuboid structure and enter the ionization region. When the gated grid electrode 21 is located on one of the sides, a detection channel can be set on the other three sides to increase the flux of neutral particles incident in the spacecraft's orbital space into the ionization region and improve detection sensitivity. After the ionized ions are stored in the ion storage potential well for a period of time, the voltage of the gated grid electrode 21 is changed to pull the ionized ions stored in the ion storage potential well out and enter the time-of-flight measurement system at the back end. The time-of-flight measurement system performs component resolution and flux intensity detection on the ionized ions to obtain the density and composition information of the neutral particles incident through the detection channels. Therefore, the neutral gas ionization source mechanism provided in this embodiment of the invention has multiple detection channels and integrates two backup electron beam emission mechanisms. The grid electrode structure formed by connecting and enclosing multiple grid electrodes is designed as a polyhedral structure. The multiple detection channels and the two electron beam emission mechanisms correspond to different sides of the grid electrode structure. By flexibly controlling the corresponding voltage of the grid electrode on each side of the grid electrode structure, an ion storage potential trap is formed in the central region of the ionization region. This provides high flexibility in potential control and makes the overall structure of the neutral gas ionization source mechanism compact and rationally distributed. It can meet the low-density and high-sensitivity measurement requirements for detecting celestial bodies with extremely low neutral gas density, such as the moon and asteroid surfaces, and can also meet the requirements for long-term operation.

[0022] In some embodiments, the grid electrode structure includes multiple channel inlet grid electrodes, two electron beam inlet grid electrodes 22, and the gated grid electrode 21. Each channel inlet grid electrode and the gated grid electrode 21 are respectively located on one side of the peripheral surface, and each channel inlet grid electrode is located between each detection channel and the ionization region. The two electron beam inlet grid electrodes 22 are respectively disposed on the first side and the second side, and the electron beam inlet grid electrodes 22 are located between the electron beam emission mechanism and the ionization region. A corresponding set negative voltage is applied to the multiple channel inlet grid electrodes, the electron beam inlet grid electrodes 22, and the gated grid electrode 21, so that an ion storage potential trap is formed in the central region of the ionization region to achieve the binding of ionized ions.

[0023] Specifically, for example, multiple channel inlet grid electrodes, two electron beam inlet grid electrodes 22, and the gated grid electrode 21 can be enclosed to form a cuboid structure or other cylindrical structure. Corresponding set negative voltages are applied to the multiple channel inlet grid electrodes, electron beam inlet grid electrodes 22, and gated grid electrodes 21, and the voltage of each grid electrode can be flexibly adjusted, so that an ion storage potential trap is formed in the central region of the ionization region. This provides high flexibility in potential control. The electron beam inlet grid electrodes 22, located on the first and second sides respectively, can be provided with corresponding light-transmitting holes to facilitate the inflow of the emitted electron beam into the ionization region. The electron beam ionizes the incident neutral particles in the ionization region, resulting in ionized ions. Transmission holes can be provided on the multiple channel inlet grid electrodes to facilitate the entry of incident neutral particles into the ionization region. Penetration holes can also be provided on the gated grid electrode 21. By changing the voltage applied to the gated grid electrode 21, the ionized ions stored for a period of time can enter the time-of-flight measurement system at the back end through the penetration holes. The transmission aperture and the penetration aperture can be set on the same horizontal plane, the axis of the light-transmitting aperture can be perpendicular to the horizontal plane, and the axes of the light-transmitting aperture, the transmission aperture and the penetration aperture can intersect in the central region of the ionization region.

[0024] In some embodiments, the plurality of detection channels include a first detection channel 23, a second detection channel 24, and a third detection channel 25. The first detection channel 23 and the gated grid electrode 21 are respectively disposed on both sides of the grid electrode structure along a first direction. The second detection channel 24 and the third detection channel 25 are respectively disposed on both sides of the grid electrode structure along a second direction. Two electron beam emitting mechanisms are disposed opposite to each other on both sides of the grid electrode structure along a third direction. The first direction, the second direction, and the third direction are approximately perpendicular to each other.

[0025] The first direction is, for example, any direction in the spacecraft's orbital space. If the first direction is set as the X direction in the coordinate system, it corresponds to the left-right direction of the neutral gas ionization source mechanism provided in this embodiment of the invention. The second direction is set as the Z direction in the coordinate system, which corresponds to the front-back direction of the neutral gas ionization source mechanism. The third direction is set as the Y direction in the coordinate system, which corresponds to the up-down direction of the neutral gas ionization source mechanism. The first detection channel 23, the second detection channel 24, and the third detection channel 25 are all located on the same horizontal plane. The flow direction of neutral particles incident through the first detection channel 23, the second detection channel 24, and the third detection channel 25 is perpendicular to the electron beam emitted by the electron beam emission mechanism. This ensures that the area where the neutral particles intersect with the electron beam is located exactly in the central region of the ionization region. This central region is an ion storage potential well, where the ions after the neutral particles are ionized are stored.

[0026] In some embodiments, the channel inlet grid electrode includes a first channel inlet grid electrode 26, a second channel inlet grid electrode 27 and a third channel inlet grid electrode 28 disposed opposite to each other. The first channel inlet grid electrode 26 is disposed opposite to the gated grid electrode 21. If a first set voltage is applied to the first channel inlet grid electrode 26 and the gated grid electrode 21, a second set voltage is applied to the second channel inlet grid electrode 27 and the third channel inlet grid electrode 28, and a third set voltage is applied to the two electron beam inlet grid electrodes 22 disposed opposite to each other, an ion storage potential trap is formed in the central region of the ionization region to trap ionized ions. The absolute value of the third set voltage is greater than the absolute value of the first set voltage, and the absolute value of the first set voltage is greater than the absolute value of the second set voltage.

[0027] The first channel inlet grid electrode 26 and the gated grid electrode 21 are subjected to the same first set voltage, the second channel inlet grid electrode 27 and the third channel inlet grid electrode 28 are subjected to the same second set voltage, and the two electron beam inlet grid electrodes 22 are subjected to the same third set voltage. This simplifies the voltage control of the grid electrodes. The six grid electrodes can be enclosed to form a cuboid structure. By controlling the voltage of the six grid electrodes, the potential formed in the ionization region can be flexibly controlled, thereby obtaining an ion storage potential trap with a high surrounding potential and a low intermediate potential.

[0028] In some embodiments, if a fourth set voltage is applied to the gated grid electrode 21, the ionized ions enter the time-of-flight measurement system through the gated grid electrode 21; wherein the absolute value of the fourth set voltage is greater than the absolute value of the third set voltage; in an exemplary embodiment, the voltage value of the third set voltage is -5V to -1V, and the voltage value of the fourth set voltage is -600V to -100V.

[0029] For example, if a voltage of -0.8V is applied to the first channel inlet grid electrode 26 and the gated grid electrode 21, a voltage of -1V is applied to the two electron beam inlet grid electrodes 22, and a voltage of -0.6V is applied to the second channel inlet grid electrode 27 and the third channel inlet grid electrode 28, an ion storage potential trap can be formed in the central region of the ionization region. The voltage values ​​applied to each grid electrode are relatively small, making them easy to control and operate. If a voltage of -400V is applied to the gated grid electrode 21, the ionized ions stored in the ion storage potential trap can be pulled out and enter the downstream time-of-flight measurement system. When the voltage applied to the gated grid electrode 21 returns to -0.8V, an ion storage potential trap can be formed in the central region of the ionization region. By working in this cyclical manner, neutral particles incident on multiple detection channels can be ionized and the ionized ions stored, thereby achieving highly sensitive detection.

[0030] In some embodiments, the electron beam emitting mechanism includes an emission source 29 and a storage lens electrode group 30, wherein the emission source 29 is used to generate an emitted electron beam, and the storage lens electrode group 30 is used to modulate the trajectory and focusing characteristics of the emitted electron beam; the two electron beam emitting mechanisms are symmetrically arranged with respect to the ionization region, and the two emission sources 29 adopt a time-sharing intermittent working system to extend the working time of the emission source 29.

[0031] The emission source 29 is, for example, a filament, which may include a tungsten filament or a LaB6 filament. The storage lens electrode group 30 may include a first lens electrode, a second lens electrode, and a third lens electrode arranged at intervals along the vertical direction. The first lens electrode, the second lens electrode, and the third lens electrode are arranged to move sequentially from the emission source 29 toward the electron beam inlet grid electrode 22. By adjusting the first lens electrode, the second lens electrode, and the third lens electrode, the trajectory of the emitted electron beam can be modulated, and the electron beam can be focused on the central region of the ionization region. When a large current is applied to the filament, the filament's lifespan is reduced due to continuous heating, thus limiting the filament's working life. Therefore, the two symmetrically arranged emission sources 29 adopt a time-sharing intermittent working system to avoid continuous heating during operation, thereby extending the working time of the emission sources 29 and thus extending the overall service life of the neutral gas ionization source mechanism provided in this embodiment of the invention.

[0032] In some embodiments, the storage lens electrode group 30 located on both sides of the ionization region is subjected to an appropriate voltage to modulate the trajectory and focusing characteristics of the emitted electron beam, thereby forming a space charge effect of the electron beam in the ionization region to reduce the potential of the central region of the ionization region.

[0033] The space charge effect refers to the collective phenomenon where the self-consistent electric (and magnetic) fields generated by the charge density of a charged particle beam influence the motion of particles within the beam. In an electron beam, this effect manifests as the electron beam charge density altering the original potential field distribution through the Poisson equation, thus generating an additional field superimposed on the applied electric field. By applying a suitable voltage to the storage lens electrode group 30, the modulated electron beam can form a space charge effect in the ionization region. This further reduces the potential in the central region of the ionization region. Combined with applying corresponding voltages to multiple grid electrodes, the potential in the ionization region is more easily controlled, resulting in a better ion storage potential trap in the central region of the ionization region, which can better confine ionized ions.

[0034] In some embodiments, the detection channel is configured as a gap formed between two opposing deflection plates 31, with the voltage polarities of the two deflection plates 31 being opposite. Specifically, by applying a high voltage with opposite polarities to the two deflection plates 31, a deflection electric field can be formed within the detection channel, deflecting charged particles incident along with neutral particles and avoiding interference with the detection of neutral particles.

[0035] In some embodiments, the detection channel is suitable for spacecraft orbital spaces with neutral particle densities ranging from 1 to 10. 10 cm -3 Preferably, the detection channel is suitable for neutral particles with even lower densities, especially for probing celestial bodies such as the Moon and asteroid surfaces where the density of neutral gas is extremely low. The detection channel is suitable for neutral particle densities ranging from 1 to 10. 6 cm -3 The neutral gas ionization source mechanism provided in this embodiment of the invention integrates multiple detection channels, which can increase the flux of neutral particles entering the ionization region and improve detection sensitivity.

[0036] The implementation methods and advantages of the embodiments of this application have been described above through multiple examples. The following describes in detail a specific processing procedure of an embodiment of the present invention with reference to the accompanying drawings and specific examples.

[0037] This invention provides a multi-channel neutral gas ionization source mechanism, including a first detection channel 23, a second detection channel 24, and a third detection channel 25. The first detection channel 23 and the gated grid electrode 21 are respectively disposed on both sides of the grid electrode structure along the X direction (left-right direction). The detection channel includes a set of deflection electrode plates, the main function of which is to apply a deflection electric field perpendicular to the incident direction of the neutral particles, deflecting the charged particles that are incident with the neutral particles, so that the charged particles cannot enter the ionization region and avoid interference with the measurement of neutral particles. Two sets of symmetrical electron beam emission mechanisms are respectively arranged along the Y direction (up-down direction) of the ionization region. The electron beam emission mechanism includes an emission source 29 and a storage lens electrode group 30. The emission source 29 is a hot filament, which can be a tungsten filament or a LaB6 filament. The emission source 29 is used to generate an emitted electron beam to ionize the neutral particles. Figure 2 The dashed arrows indicate the emission direction of the electron beam. The upper and lower filaments form an effective backup, and during use, the two filaments can be operated sequentially in a time-sharing manner to increase the lifespan of the ionization source. The function of the storage lens electrode group is to modulate the electron beam trajectory and focusing characteristics. On the left side of the ionization region is the first channel entrance grid electrode 26, and on the right side is the gated grid electrode 21. The upper and lower sides of the ionization region are both electron beam entrance grid electrodes 22, and the front and rear sides of the ionization region are the second channel entrance grid electrode 27 and the third channel entrance grid electrode 28, respectively. Applying corresponding voltages to the six grid electrodes respectively forms an ion storage potential trap within the ionization region to confine the ionized ions. By applying a suitable voltage to the storage lens electrode assembly 30, the trajectory and focusing characteristics of the emitted electron beam are modulated. The modulated electron beam can form a space charge effect in the ionization region, which further reduces the potential in the central region of the ionization region. Combined with applying corresponding voltages to multiple grid electrodes, the potential in the ionization region is more easily controlled, resulting in a better ion storage potential trap in the central region of the ionization region, which can better confine the ionized ions. After the ionized ions are stored in the ion storage potential trap for a period of time, the voltage of the gated grid electrode 21 is changed, for example, by applying a negative voltage of several hundred volts to the gated grid electrode 21, the ions in the ion storage potential trap are accelerated out. After the ionized ions are pulled out, the voltage of the gated grid electrode will return to its previous state (for example, applying a voltage of -0.8V to the gated grid electrode 21 at this time), thus achieving the storage of the ionized ions. This cyclical operation can ionize neutral particles incident on multiple detection channels and store the ionized ions, thereby achieving high-sensitivity detection. Figures 2-3 The solid arrow in the figure indicates the incident direction of the neutral particles. They are ionized in the ionization region to form ionized ions. The ionized ions are emitted through the gated grid electrode 21 and can enter the time-of-flight measurement system 40 at the back end.

[0038] Based on the multi-channel neutral gas ionization source mechanism in the above embodiments, a corresponding simulation model of the neutral gas ionization source mechanism is constructed in finite element simulation software. A -1V voltage is simulated to be applied to the electron beam inlet grid electrode 22, a -0.8V voltage is simulated to be applied to the first channel inlet grid electrode 26 and the gated grid electrode 21, and a -0.6V voltage is simulated to be applied to the second channel inlet grid electrode 27 and the third channel inlet grid electrode 28. The six grid electrodes work together, and the space charge effect of the electron beam forms an ion storage potential trap in the central region of the ionization region, confining the ionized ions. A -70V voltage is simulated to be applied to the emission source 29, and the first, second, and third lens electrodes in the storage lens electrode group 30 are simulated to be applied with -65V, 0V, and +2V voltages respectively, modulating the trajectory and focusing characteristics of the emitted electron beam. The modulated electron beam can form a space charge effect in the ionization region. At this time, the ionization region is cut along the X-axis to obtain... Figure 6 The diagram shows the potential distribution of the ionization region in the ZY plane. From the diagram, it can be seen that the potential is high at the outer periphery of the ionization region near the second channel inlet grid electrode 27 and the third channel inlet grid electrode 28 along the Z direction. At this time, the potential at the outer periphery is about -0.78V, and the potential at the center is about -0.84V. It can be seen that the potential is high at the periphery and low at the center of the ionization region, which can form an ion storage potential trap and store the ionized ions well.

[0039] Figure 7 The diagram shows the change in Ar+ density in the central region of the ionization region over time without an ion storage potential trap. It is evident that the Ar+ density is approximately 1 × 10⁻⁶. -5 It quickly decreased to 0 within s. Figure 8 This shows the change in Ar+ density at the center of the ionization region over time in the presence of an ion storage potential trap, at approximately 2.5 × 10⁻⁶. -4 The Ar+ density within s can be maintained at 0.7-0.9×10 12 m -3 ,contrast Figure 7 In the central region of the ionization region, Ar+ ions can be stored for a longer time after ionization, provided there is an ion storage potential trap. Figure 7 and Figure 8 The horizontal axis represents time in seconds, and the vertical axis represents the number density of Ar+ ions in m³. -3 .

[0040] This invention also provides a detection device, with reference to... Figure 9The system includes: a neutral gas ionization source mechanism 20 and a time-of-flight measurement system 40 as described in the above embodiments. The ionized ions output by the neutral gas ionization source mechanism 20 enter the time-of-flight measurement system 40 through the gated grid electrode 21. The time-of-flight measurement system 40 is used to perform composition resolution and flux intensity detection on the ionized ions in order to obtain the density and composition information of neutral particles in the spacecraft's orbital space incident through the detection channel.

[0041] The voltage application time of the gated grid electrode 21 at the inlet of the time-of-flight measurement system 40 serves as the initial electrical signal for the ionized ions to enter the time-of-flight system. The ionized ions, for example, are positively charged ions. These positively charged ions continue to fly within the flight zone of the time-of-flight measurement system 40, and at the outlet of the system, they strike a microchannel plate (MCP), generating a termination electrical signal for ion flight. Measuring the time difference between the termination signal and the initial electrical signal yields the flight time of the positively charged ion over a specific distance, thus obtaining the ion's velocity information. Combined with the positively charged ion's energy information, the mass (composition) information of the positively charged ion can be obtained. The composition of the positively charged ion corresponds to the composition of neutral particles. The positively charged ion's energy information includes the initial energy and the accelerated energy of the ion after ionization.

[0042] The advantages of the technical solution of this invention are: (1) By setting two filaments as the emission source, the two filaments serve as backups for each other and can work in a time-sharing manner, which can effectively increase the service life of the ionization source mechanism; (2) By setting up multiple detection channels, the flux of neutral particles entering the ionization region in the spacecraft's orbital space is increased, thereby improving the detection sensitivity of the equipment; (3) By setting adjustable voltage detection channel inlet grid electrode, electron beam inlet grid electrode, gated grid electrode and storage lens electrode group, a better ion storage potential trap can be achieved, and thus long-term storage of ions can be achieved. (4) Deflection electrode groups are set at the entrance of the detection channel, which can effectively suppress charged particles that are incident at the same time and reduce the interference of charged particles on neutral particles. This is especially important for the detection of low-density neutral particles in the spacecraft's orbital space.

[0043] 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 gas ionization source mechanism with multiple channels, characterized in that, It includes a grid electrode structure, an electron beam emission mechanism, and multiple detection channels, among which, The grid electrode structure includes multiple grid electrodes connected and enclosed to form a polyhedral structure. The inner cavity of the polyhedral structure constitutes an ionization region. Applying a corresponding voltage to the multiple grid electrodes causes the central region of the ionization region to form an ion storage potential trap for storing ionized ions. The grid electrode structure has a first side and a second side arranged opposite to each other, as well as a peripheral surface connecting the first side and the second side. A gated grid electrode is provided on one side of the peripheral surface. By changing the voltage of the gated grid electrode, ionized ions can enter the time-of-flight measurement system through the gated grid electrode. The electron beam emitting mechanism includes two electron beam emitting mechanisms, which are disposed on opposite sides of the grid electrode structure along the first direction. The electron beam emitting mechanism is used to emit an electron beam. The emitted electron beam enters the ionization region from the first side and the second side, respectively, so as to ionize neutral particles incident through multiple detection channels in the ionization region. The plurality of detection channels are located on the outer side of the circumferential surface. The plurality of detection channels are used to deflect charged particles incident in the spacecraft's orbital space, so that incident neutral particles enter the ionization region via the side of the circumferential surface. One of the plurality of detection channels is located on the outer side of the side opposite to the gated grid electrode.

2. The neutral gas ionization source mechanism according to claim 1, characterized in that, The grid electrode structure includes multiple channel inlet grid electrodes, two electron beam inlet grid electrodes, and the gated grid electrode. Each channel inlet grid electrode and the gated grid electrode are respectively located on one side of the circumferential surface, and each channel inlet grid electrode is located between each detection channel and the ionization region. The two electron beam inlet grid electrodes are respectively disposed on the first side and the second side, and the electron beam inlet grid electrode is located between the electron beam emission mechanism and the ionization region. A corresponding set negative voltage is applied to the multiple channel inlet grid electrodes, electron beam inlet grid electrodes and gated grid electrodes respectively, so that an ion storage potential trap is formed in the central region of the ionization region to bind the ionized ions.

3. The neutral gas ionization source mechanism according to claim 2, characterized in that, The plurality of detection channels include a first detection channel, a second detection channel and a third detection channel. The first detection channel and the gated grid electrode are respectively disposed on both sides of the grid electrode structure along a first direction. The second detection channel and the third detection channel are respectively disposed on both sides of the grid electrode structure along a second direction. Two electron beam emission mechanisms are disposed opposite to each other on both sides of the grid electrode structure along a third direction. The first, second, and third directions are roughly perpendicular to each other.

4. The neutral gas ionization source mechanism according to claim 3, characterized in that, The channel inlet grid electrode includes a first channel inlet grid electrode, a second channel inlet grid electrode, and a third channel inlet grid electrode disposed opposite to each other. The first channel inlet grid electrode is disposed opposite to the gated grid electrode. If a first predetermined voltage is applied to the first channel inlet gate electrode and the gated gate electrode, a second predetermined voltage is applied to the second channel inlet gate electrode and the third channel inlet gate electrode, and a third predetermined voltage is applied to the two opposing electron beam inlet gate electrodes, an ion storage potential trap is formed in the central region of the ionization region to confine the ionized ions. The absolute value of the third set voltage is greater than the absolute value of the first set voltage, and the absolute value of the first set voltage is greater than the absolute value of the second set voltage.

5. The neutral gas ionization source mechanism according to claim 4, characterized in that, If a fourth preset voltage is applied to the gated grid electrode, causing ionized ions to enter the time-of-flight measurement system via the gated grid electrode; wherein... The absolute value of the fourth set voltage is greater than the absolute value of the third set voltage; The third set voltage has a value of -5V to -1V, and the fourth set voltage has a value of -600V to -100V.

6. The neutral gas ionization source mechanism according to claim 1, characterized in that, The electron beam emitting mechanism includes an emission source and a storage lens electrode assembly, wherein... The emission source is used to generate an emitted electron beam, and the storage lens electrode group is used to modulate the trajectory and focusing characteristics of the emitted electron beam. Two electron beam emitting mechanisms are symmetrically arranged around the ionization region, and the two emission sources operate in a time-sharing intermittent mode to extend the operating time of the emission sources.

7. The neutral gas ionization source mechanism according to claim 6, characterized in that, By applying an appropriate voltage to the storage lens electrode group located on both sides of the ionization region, the trajectory and focusing characteristics of the emitted electron beam are modulated, thereby forming a space charge effect of the electron beam in the ionization region, so as to reduce the potential of the central region of the ionization region.

8. The neutral gas ionization source mechanism according to claim 1, characterized in that, The detection channel is configured to consist of a gap formed between two oppositely positioned deflection plates, with the voltage polarities between the two deflection plates being opposite.

9. The neutral gas ionization source mechanism according to any one of claims 1-8, characterized in that, The detection channel is suitable for neutral particle densities in the spacecraft's orbital space ranging from 1 to 10. 10 cm -3 .

10. A detection device, characterized in that, include: The neutral gas ionization source mechanism and time-of-flight measurement system as described in any one of claims 1-9, wherein, The ionized ions output from the neutral gas ionization source mechanism enter the time-of-flight measurement system through the gated grid electrode. The time-of-flight measurement system is used to perform composition resolution and flux intensity detection on the ionized ions in order to obtain the density and composition information of neutral particles in the spacecraft's orbital space that is incident on the detection channel.

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