Arresting potential energy analysis device

Abstract

The application discloses a retarding potential analysis device, which is characterized in that a plurality of retarding structure units are arranged between an entrance electrode and a retarding electrode, each of the retarding structure units forms a spherical equipotential surface with the entrance as the center at the entrance thereof, the flying direction of the incoming high-energy charged particles is always the same as the direction of the electric field, and the spherical equipotential surface is obtained on the basis of a planar assembly structure. Compared with a planar RPA, the measuring error caused by the inconsistency between the flying direction of the charged particles and the direction of the retarding electric field is greatly reduced, and compared with a spherical RPA, since the spherical center of the equipotential surface is located in the interior of the retarding structure unit, the distance between the RPA and the initial position of the charged particle source can be selected at will, and the measurement is more flexible. By arranging a plurality of retarding structure unit arrays, the measurement cross-sectional area of the plume can be increased. In addition, all the components can be realized by using traditional processing modes, and the cost is low.

Description

Technical Field

[0001] This invention relates to the field of space electric thruster technology, and in particular, to a device for analyzing hindrance potential energy. Background Technology

[0002] The energy distribution of heavy ions is a crucial characteristic of electric thruster plumes, indirectly reflecting fundamental performance aspects such as the specific impulse of the thruster. Furthermore, because the thruster beam is emitted radially, the angle between the thruster and the spacecraft determines whether the plume can reach sensitive surfaces, thus affecting spacecraft performance. Therefore, space applications of thrusters must address the compatibility issue between the plume and the spacecraft, with heavy ion energy distribution being the most critical evaluation parameter. A hindrance potential energy analyzer (RPA) is a commonly used device for measuring the heavy ion energy distribution of plumes. Meanwhile, as... Figure 1 As shown, in an electrospray thruster using ionic liquid as the propellant, ions are extracted and accelerated under the action of an applied electric field of corresponding polarity to form an ion beam. Due to the working physical mechanism of the ionic liquid electrospray thruster and the properties of the ionic liquid, the ions in the beam are polydisperse, containing monomers and ion clusters (dimers, trimers, and even other polymers). Under the action of the electric field between the extraction gate and the emitter, the ion clusters will break up with a certain probability to form new ions / ion clusters and neutral molecules. Understanding the breakup rate of ion clusters in the acceleration region is of great significance for propellant selection and thruster optimization design. Using a hindrance potential energy analyzer (RPA) to accurately measure the energy of charged particles in the beam is an effective method to obtain the ion cluster breakup rate.

[0003] like Figure 2 As shown, a conventional resistive potential energy analyzer (RPA) has a planar structure, consisting of at least four planar grids and one collector. Grid I is suspended to reduce the RPA's disturbance to the plasma; Grid II is connected to a negative bias voltage (V2) to repel electrons in the plasma; Grid III is connected to a scanning voltage (V3) to selectively transmit ions; Grid IV is connected to a negative bias voltage to suppress upstream electrons from reaching the collector and to suppress secondary electrons generated by high-energy ions bombarding the collector. During measurement, the RPA is placed in the beam. The voltage on Grid III and Grid II establish a resistive electric field perpendicular to the normal direction of the grid surface, allowing only ions with energy E≥q(V3-V2) to pass through and eventually reach the collector, where q represents the ion charge number. By scanning the bias voltage on Grid III, the current collected by the collector and the corresponding resistive grid scanning voltage form an IV curve. Analysis of this curve yields the ion energy distribution.

[0004] However, because the beam of the electric thruster is radial and has a certain divergence angle, the flight direction of charged particles deviates from the thruster's exit normal direction. In a planar RPA configuration, the direction of the blocking electric field between the grids is the same as the grid normal direction. In actual measurements, after a charged particle enters the RPA, its flight direction forms an angle with the direction of the blocking electric field. The electric field can only block the velocity component of the charged particle along the electric field direction; the velocity component perpendicular to the electric field direction remains unchanged. Therefore, the actual cutoff energy of the charged particle is related to its incident angle, resulting in a measurement error related to the incident angle. If the incident angle of each ion is known, the measurement results can be corrected. However, the actual direction of the charged particles exhibits certain distribution characteristics, and their incident direction cannot be accurately measured.

[0005] Considering that the electric field in RPA is related to the gate configuration, such as Figure 3 As shown, a concentric spherical gate structure has emerged, which can form an electric field distribution pointing towards the center of the gate sphere between the gates. If the initial position of the charged particle's flight is located at the center of the gate sphere, the incident direction of the charged particle will always be consistent with the direction of the blocking electric field, which can reduce or even eliminate the error introduced by beam divergence. However, once the curvature of the spherical gate is determined, in order to improve measurement accuracy, the distance between the spherical RPA and the initial position of the charged particle source (i.e., the outlet of the thruster under test) will be fixed, resulting in poor measurement flexibility. Furthermore, high-precision spherical gates are difficult to manufacture. To ensure high particle transmittance, the gate is generally made of a thin conductor material with a thickness on the order of tens to hundreds of micrometers. The axis of the gate apertures on it must be consistent with the normal direction of the sphere, and the linewidth between the gate apertures is on the order of tens of micrometers. The commonly used method for manufacturing curved gates is to first perform planar gate aperture processing, and then shape the planar gate into a spherical gate with a certain curvature. While forming vias in planar gates is relatively simple, the method of first forming the vias and then shaping the gate into a spherical gate is prone to breakage between the gate vias, resulting in extremely low yield. Furthermore, due to inelastic deformation during the shaping process, the cross-sectional dimensions of the gate vias will change compared to the unformed planar gate. During gate assembly, it is difficult to ensure high coaxial assembly accuracy for the vias at the same positions on each gate. If the method of first shaping the planar gate into a spherical gate and then performing via forming is adopted, in order to ensure high via forming accuracy, the via forming process requires the use of non-traditional processing technologies such as ultrafast laser processing, which is extremely expensive. Summary of the Invention

[0006] This invention provides a hindrance potential energy analysis device to solve the technical problems of large measurement error in existing planar RPAs and difficult and costly gate processing in spherical RPAs.

[0007] According to one aspect of the present invention, a hindrance potential energy analysis device is provided, comprising an inlet electrode, a hindrance electrode, a first grid, a second grid, and a collector electrode arranged sequentially along the incoming flow direction of the plume to be measured. Insulating pads are provided between the inlet electrode and the hindrance electrode, between the first grid and the second grid, and between the second grid and the collector electrode. The hindrance electrode is in close contact with the first grid. The inlet electrode is grounded, the second grid is connected to a negative potential, and the hindrance electrode and the first grid are connected to a scanning voltage. The inlet electrode is used to repel electrons in the plume to be measured. A hindrance electric field is formed between the hindrance electrode and the inlet electrode to select charged particles of corresponding energy to pass through. The second grid is used to suppress high-energy charged particles from bombarding the collector electrode to generate secondary electrons. The collector electrode is connected to a power supply reference ground to collect ions. A plurality of hindrance structure units are arranged between the inlet electrode and the hindrance electrode. Each hindrance structure unit forms a spherical equipotential surface centered on the inlet at its inlet, so that the flight direction of high-energy charged particles entering the hindrance structure unit is always the same as the direction of the electric field within the hindrance structure unit.

[0008] Furthermore, the blocking electrode is provided with a plurality of cylindrical cavity arrays, each cylindrical cavity having an open downstream end and a coaxial micropore at its upstream end. The inlet electrode is provided with a plurality of through-type conical inlet arrays, the array parameters and number of which are the same as those of the cylindrical cavity arrays. Each conical inlet is coaxially arranged with each micropore. A conical protrusion is provided on the side of the conical inlet near the blocking electrode, the bottom end of which extends into the micropore, or the bottom end of which is flush with the top end of the micropore. Each conical inlet and the cylindrical cavity constitute a blocking structure unit.

[0009] Furthermore, the ratio of the diameter of the cylindrical cavity to the diameter of the small end face of the conical inlet is greater than 5, and its diameter-to-depth ratio is greater than 1.5 and less than 3.

[0010] Furthermore, the tapered inlet has a taper of 90° and a small end face diameter of 0.8 mm, while the cylindrical cavity has a diameter of 6 mm and a depth of 3 mm.

[0011] Furthermore, it also includes a third gate located upstream of the inlet electrode, with an insulating pad between the third gate and the inlet electrode, and the third gate being in a suspended state.

[0012] Furthermore, each gate includes an outer frame and a gate aperture region. The outer frame has a thick-walled structure, and the gate aperture region has a thin-walled structure. The gate aperture region is provided with a number of arrayed gate apertures. The array arrangement of the gate apertures adopts the same block-type gate aperture array group as the cylindrical cavity array, or adopts a single array arrangement in which the gate aperture region surrounds all the cylindrical cavity regions.

[0013] Furthermore, the gate holes are either round or square.

[0014] Furthermore, the collecting electrode adopts a conical cavity structure made of a particle-resistant material, or the collecting electrode adopts a flat plate structure made of a particle-resistant material.

[0015] Furthermore, the inlet electrode, blocking electrode, insulating pad, and collector electrode are obtained by mechanical processing, while the gate electrode is obtained by electrochemical etching or mechanical processing.

[0016] Furthermore, it also includes a grounded shielding enclosure for shielding against interference.

[0017] The present invention has the following effects:

[0018] The hindrance potential energy analysis device of the present invention comprises several hindrance structure units arranged between the inlet electrode and the hindrance electrode. Each hindrance structure unit forms a spherical equipotential surface centered at its inlet, ensuring that the flight direction of high-energy charged particles entering the hindrance structure unit is always the same as the direction of the electric field within the hindrance structure unit. This achieves a spherical equipotential surface based on a planar assembly structure. Compared to planar RPAs, this significantly reduces measurement errors caused by the inconsistency between the flight direction of charged particles and the direction of the hindrance electric field. Compared to spherical RPAs, since the center of the equipotential surface is located inside the hindrance structure unit, it eliminates the need to consider the grid curvature to determine the placement of the RPA relative to the measured particle source (i.e., the thruster). The distance between the RPA and the initial position of the charged particle source (i.e., the outlet of the measured thruster) can be arbitrarily selected, making the measurement more flexible. Furthermore, by arranging multiple hindrance structure unit arrays, the measurement cross-sectional area of ​​the plume can be increased, increasing the number of charged particles entering the RPA and improving the detection signal strength. In addition, all components in the structure of the present invention can be manufactured using conventional processing methods, resulting in low cost.

[0019] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0020] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0021] Figure 1 This is a schematic diagram illustrating the working principle of an existing electro-spray thruster.

[0022] Figure 2 This is a schematic diagram of the principle of existing planar RPA.

[0023] Figure 3 This is a schematic diagram of the principle of an existing spherical RPA.

[0024] Figure 4 This is a cross-sectional structural schematic diagram of the hindrance potential energy analysis device according to a preferred embodiment of the present invention.

[0025] Figure 5 This is a schematic diagram of the blocking electrode according to a preferred embodiment of the present invention.

[0026] Figure 6 This is a schematic diagram of the inlet electrode structure of a preferred embodiment of the present invention.

[0027] Figure 7 This is a schematic diagram of the blocking structure unit of a preferred embodiment of the present invention.

[0028] Figure 8 This is a schematic diagram of the potential distribution within the blocking structure unit of a preferred embodiment of the present invention.

[0029] Figure 9 This is a schematic diagram of a preferred embodiment of the present invention, showing that the gate adopts a segmented gate hole array arrangement.

[0030] Figure 10 This is a schematic diagram of a preferred embodiment of the present invention, showing a gate array arrangement.

[0031] Figure 11 This is a schematic diagram of a preferred embodiment of the present invention, showing that the circular gate holes on the gate are arranged in a hexagonal array. Detailed Implementation

[0032] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0033] like Figure 4As shown, a preferred embodiment of the present invention provides a hindrance potential energy analysis device, comprising an inlet electrode, a hindrance electrode, a first gate, a second gate, and a collector electrode arranged sequentially along the incoming flow direction of the plume being measured. Insulating pads are provided between the inlet electrode and the hindrance electrode, between the first gate and the second gate, and between the second gate and the collector electrode to achieve electrical isolation. The hindrance electrode is in close contact with the first gate. The inlet electrode is grounded, the second gate is connected to a negative potential, and the hindrance electrode and the first gate are connected to a scanning voltage. Except for the insulating pads, the inlet electrode, hindrance electrode, first gate, second gate, and collector electrode are all made of conductive material. The inlet electrode repels electrons in the plume being measured. A hindrance electric field is formed between the hindrance electrode and the inlet electrode to select charged particles of corresponding energy for passage. The second gate suppresses the generation of secondary electrons by high-energy charged particles bombarding the collector electrode. The collector electrode is connected to a power supply reference ground for collecting ions. Several retardation structure units are arranged between the inlet electrode and the retardation electrode. Each retardation structure unit forms a spherical equipotential surface centered at its inlet, ensuring that the flight direction of high-energy charged particles entering the retardation structure unit is always the same as the direction of the electric field within the retardation structure unit. This significantly reduces measurement errors caused by the inconsistency between the flight direction of charged particles and the direction of the retardation electric field, greatly improving measurement accuracy. It can be understood that by scanning the bias voltage on the retardation electrode and the first gate, and collecting the current on the collector electrode, an IV curve is formed. Analysis of the IV curve yields the ion energy distribution.

[0034] It is understood that the hindrance potential energy analysis device of this embodiment, by setting several hindrance structure units between the inlet electrode and the hindrance electrode, and each hindrance structure unit forming a spherical equipotential surface centered at its inlet, ensures that the flight direction of high-energy charged particles entering the hindrance structure unit is always the same as the electric field direction within the hindrance structure unit, thus obtaining a spherical equipotential surface based on a planar assembly structure. Compared to planar RPA, this greatly reduces the measurement error caused by the inconsistency between the flight direction of charged particles and the direction of the hindrance electric field. Compared to spherical RPA, since the center of the equipotential surface is located inside the hindrance structure unit, it is not necessary to consider the gate curvature to determine the placement position of the RPA relative to the measured particle source (i.e., the thruster). The distance between the RPA and the initial position of the charged particle source (i.e., the outlet of the measured thruster) can be arbitrarily selected, making the measurement more flexible. At the same time, by setting multiple hindrance structure unit arrays, the measurement cross-sectional area of ​​the plume can be increased, the number of charged particles entering the RPA can be increased, and the detection signal strength can be improved. In addition, all components in the structure of this invention can be realized using conventional processing methods, resulting in low cost.

[0035] Specifically, such as Figure 5As shown, the blocking electrode is provided with a plurality of cylindrical cavity arrays, each cylindrical cavity being open downstream and having coaxial micropores upstream. Figure 6 As shown, the inlet electrode is located upstream of the blocking electrode. The inlet electrode has a through-type array of several conical inlets. The array parameters and number of the conical inlets are the same as those of the cylindrical cavity array, and each conical inlet is coaxially arranged with each micropore. Each conical inlet has a conical protrusion on the side near the blocking electrode. When the inlet electrode and the blocking electrode are assembled, the bottom end of the conical protrusion slightly extends into the micropore, or the bottom end of the conical protrusion is flush with the top end of the micropore. Each conical inlet and the cylindrical cavity constitute a blocking structure unit, such as... Figure 7 As shown.

[0036] It is understandable that, since the blocking electrode and the first gate are connected to a high potential, if the influence of the inlet electrode potential is not considered, the potential in each cylindrical cavity will be equal. When the inlet electrode is connected to a low potential, because the conical inlet is relatively small compared to the cylindrical cavity, an electric field pointing towards the inlet electrode will be generated in the cylindrical cavity, which can form an approximately spherical blocking potential distribution in the cylindrical cavity, such as... Figure 8 As shown, a spherical equipotential surface centered on the entrance of the retardation structure unit is formed near the entrance, ensuring that the flight direction of high-energy charged ions entering the retardation structure unit from the conical entrance is always the same as the direction of the retardation electric field within the retardation structure unit. The entrance of the retardation structure unit refers to the junction between the conical entrance of the entrance electrode and the micropore of the retardation electrode.

[0037] Optionally, the shape of the equipotential surface in the blocking structure unit is mainly related to its inlet size, the diameter of the cylindrical cavity, and its depth. To ensure that the blocking potential distribution within the cylindrical cavity is closer to that of a sphere, the ratio of the diameter of the cylindrical cavity to the diameter of the small end face of the conical inlet is greater than 5, and its diameter-to-depth ratio is greater than 1.5 and less than 3. Preferably, the conical inlet has a taper of 90° and a small end face diameter of 0.8 mm, and the cylindrical cavity has a diameter of 6 mm and a depth of 3 mm.

[0038] Optionally, when the plume being measured contains only charged particles of a single polarity, such as for measuring the beam ion energy of an ion liquid electrospray thruster, the inlet electrode has the same potential as the extraction grid of the ion liquid electrospray thruster to avoid interference from the inlet electrode to the plume being measured, which is beneficial to further improve the measurement accuracy.

[0039] In addition, the hindrance potential energy analysis device also includes a third gate located upstream of the inlet electrode. An insulating pad is provided between the third gate and the inlet electrode. The third gate is in a suspended state to avoid interfering with the measured plume, thereby further improving the measurement accuracy.

[0040] Understandable, such as Figure 9 and Figure 10 As shown, each gate includes an outer frame and a gate aperture region. The outer frame has a thick-walled structure, which greatly improves the overall rigidity of the gate and facilitates installation and positioning. The gate aperture region has a thin-walled structure, which improves particle throughput. The gate aperture region contains several arrayed gate apertures. The array arrangement of the gate apertures adopts the same segmented gate aperture array group as the cylindrical cavity array, that is, each gate aperture array group corresponds to one cylindrical cavity, or the gate apertures adopt a single array arrangement and the gate aperture region surrounds all the cylindrical cavity regions. The structures of the first gate, second gate, and third gate can be the same or different. For example, the first gate adopts a segmented gate aperture array group, while the second and third gates adopt a single array arrangement. However, the gate apertures of the first and second gates must be aligned to improve particle throughput.

[0041] Furthermore, the gate vias on each gate can be either circular or square. Considering the limitations of linewidth in actual manufacturing, square vias are preferred, as they can improve the overall transmittance of the gate for the same linewidth. When the gate vias are designed as circular, a hexagonal array arrangement is preferred, such as... Figure 11 As shown, this is done to improve particle transmittance. The size of the gate aperture should not be too large, and it is necessary to ensure that the potential at the center of the aperture is not less than 90% of the gate potential.

[0042] Furthermore, the collecting electrode employs a conical internal cavity structure, which avoids direct impact from passing high-energy particles and reduces the emission of secondary electrons. Alternatively, the collecting electrode can be a flat plate structure made of particle-resistant materials such as tungsten, molybdenum, or high-density graphite, which can also reduce the emission of secondary electrons. The present invention preferably uses a conical internal cavity structure, which is beneficial for cost reduction.

[0043] In addition, the inlet electrode, blocking electrode, insulating pad and collector electrode are obtained by mechanical processing, and the gate is obtained by electrochemical etching or mechanical processing. All parts are obtained by traditional processing methods, which greatly reduces the manufacturing cost.

[0044] In addition, the hindrance potential energy analysis device also includes a grounded shielded shell for shielding interference. The shielded shell partially surrounds the outside of the inlet electrode, the hindrance electrode, the first gate, the second gate, and the collector electrode, providing a structure for mounting and positioning the various components.

[0045] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A device for analyzing the energy of a hindrance potential, characterized in that, The device includes an inlet electrode, a blocking electrode, a first grid, a second grid, and a collector, arranged sequentially along the incoming flow direction of the plume being measured. Insulating pads are provided between the inlet electrode and the blocking electrode, between the first grid and the second grid, and between the second grid and the collector. The blocking electrode and the first grid are in close contact. The inlet electrode is grounded, the second grid is connected to a negative potential, and the blocking electrode and the first grid are connected to a scanning voltage. The inlet electrode is used to repel electrons in the plume being measured. A blocking electric field is formed between the blocking electrode and the inlet electrode to select charged particles of corresponding energy to pass through. The second grid is used to suppress the secondary electrons generated by high-energy charged particles bombarding the collector. The collector is connected to the power supply reference ground to collect charged particles. Several blocking structure units are arranged between the inlet electrode and the blocking electrode. Each blocking structure unit forms a spherical equipotential surface centered on the inlet at its inlet, so that the flight direction of high-energy charged particles entering the blocking structure unit is always the same as the direction of the electric field within the blocking structure unit. The blocking electrode is provided with a plurality of cylindrical cavity arrays, each cylindrical cavity having an open downstream end and a coaxial micropore at its upstream end. The inlet electrode is provided with a plurality of through-type conical inlet arrays, the array parameters and number of which are the same as those of the cylindrical cavity arrays. Each conical inlet is coaxially arranged with each micropore. A conical protrusion is provided on the side of the conical inlet near the blocking electrode, the bottom end of which extends into the micropore, or the bottom end of which is flush with the top end of the micropore. Each conical inlet and the cylindrical cavity constitute a blocking structure unit.

2. The hindrance potential energy analysis device as described in claim 1, characterized in that, The ratio of the diameter of the cylindrical cavity to the diameter of the small end face of the conical inlet is greater than 5, and the diameter-to-depth ratio is greater than 1.5 and less than 3.

3. The hindrance potential energy analysis device as described in claim 1, characterized in that, The tapered inlet has a taper of 90° and a small end face diameter of 0.8 mm, while the cylindrical cavity has a diameter of 6 mm and a depth of 3 mm.

4. The hindrance potential energy analysis device as described in claim 1, characterized in that, It also includes a third gate located upstream of the inlet electrode, with an insulating pad between the third gate and the inlet electrode, and the third gate is in a floating state.

5. The hindrance potential energy analysis device as described in claim 1, characterized in that, Each gate includes an outer frame and a gate aperture region. The outer frame has a thick-walled structure, and the gate aperture region has a thin-walled structure. The gate aperture region is provided with a number of arrayed gate apertures. The array arrangement of the gate apertures adopts the same block-type gate aperture array group as the cylindrical cavity array, or adopts a single array arrangement in which the gate aperture region surrounds all the cylindrical cavity regions.

6. The hindrance potential energy analysis device as described in claim 5, characterized in that, The grid holes can be round or square.

7. The hindrance potential energy analysis device as described in claim 1, characterized in that, The collecting electrode adopts a conical cavity structure made of a particle-resistant material, or the collecting electrode adopts a flat plate structure made of a particle-resistant material.

8. The hindrance potential energy analysis device as described in claim 1, characterized in that, The inlet electrode, blocking electrode, insulating pad, and collector electrode are obtained by mechanical processing, while the gate electrode is obtained by electrochemical etching or mechanical processing.

9. The hindrance potential energy analysis device as described in claim 1, characterized in that, It also includes a grounded shielding enclosure for shielding against interference.

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