CN-116381383-B - Retarding potential energy analysis device

CN116381383BCN 116381383 BCN116381383 BCN 116381383BCN-116381383-B

Abstract

The invention discloses a retarding potential energy analysis device, which is characterized in that a plurality of retarding structure units are arranged between an inlet electrode and a retarding electrode, each retarding structure unit forms a spherical equipotential surface taking the inlet as the center at the inlet, so that the flying direction of high-energy charged particles entering the retarding structure unit is always the same as the direction of an electric field, and the spherical equipotential surface is obtained on the basis of a planar assembly structure. Compared with the plane RPA, the method greatly reduces the measurement error caused by inconsistent flying direction of the charged particles and the direction of the blocking electric field, and compared with the spherical RPA, the method has the advantages that 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 because the spherical center of the equipotential surface is positioned in the blocking structural unit. By providing a plurality of blocking structure unit arrays, the measured cross-sectional area of the plume can be increased. In addition, all parts can be realized by adopting a traditional processing mode, and the cost is low.

Inventors

ZHANG YING
GUO DAWEI
CHENG MOUSEN
YANG XIONG
LI XIAOKANG
Che Bixuan

Assignees

中国人民解放军国防科技大学

Dates

Publication Date: 20260505
Application Date: 20230329

Claims (9)

1. The blocking potential energy analysis device is characterized by comprising an inlet electrode, a blocking electrode, a first grid, a second grid and a collector which are sequentially arranged along the incoming flow direction of a detected plume, insulating pads are arranged 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 is tightly contacted with the first grid, the inlet electrode is grounded, the second grid is connected with negative potential, the blocking electrode and the first grid are connected with scanning voltage, the inlet electrode is used for repelling electrons in the detected plume, a blocking electric field is formed between the blocking electrode and the inlet electrode and used for selecting charged particles with corresponding energy to permeate, the second grid is used for inhibiting the high-energy charged particles from bombarding the collector to generate secondary electrons, the collector is connected with a power supply reference ground and used for collecting the charged particles, and a plurality of blocking structure units are arranged between the inlet electrode and the blocking structure units, and each blocking structure unit forms a spherical equipotential surface taking the inlet as a center at the inlet, so that the flying direction of the high-energy charged particles entering the blocking structure unit is always the same as the flying direction in the blocking structure unit; The device is characterized in that a plurality of cylindrical cavity arrays are arranged on the retarding electrode, coaxial micropores are formed in the downstream opening and the upstream opening of each cylindrical cavity, a plurality of penetrating conical inlet arrays are arranged on the inlet electrode, the array parameters and the number of the conical inlet arrays are the same as those of the cylindrical cavity arrays, each conical inlet is coaxially arranged with each micropore, a conical bulge is arranged on one side, close to the retarding electrode, of each conical inlet, the bottom end of each conical bulge extends into each micropore, or the bottom end of each conical bulge is flush with the top end of each micropore, and each conical inlet and each cylindrical cavity form a retarding structural unit.
2. The retarding potential energy analyzing device as set forth in claim 1, wherein the ratio of the diameter of the cylindrical cavity to the diameter of the small end face of the tapered inlet is greater than 5 and the ratio of the diameter to the depth is greater than 1.5 and less than 3.
3. The retarding potential energy analyzing device as set forth in claim 1, wherein the taper of the tapered inlet is 90 °, the diameter of the small end face is 0.8mm, and the diameter of the cylindrical cavity is 6mm and the depth is 3mm.
4. The device of claim 1, further comprising a third grid disposed upstream of the inlet electrode, an insulating pad disposed between the third grid and the inlet electrode, the third grid being in a suspended state.
5. The device for analyzing the retardation potential energy as claimed in claim 1, wherein each grid electrode comprises an outer frame and a grid hole area, the outer frame is of a thick-wall structure, the grid hole area is of a thin-wall structure, a plurality of grid holes distributed in an array are arranged in the grid hole area, wherein the array arrangement mode of the grid holes adopts a block grid hole array group which is the same as that of the cylindrical cavity array, or the grid holes are arranged in a single array mode, and all the cylindrical cavity areas are surrounded by the grid hole area.
6. The device for analyzing retardation potential energy of claim 5, wherein the gate hole is a round hole or a square hole.
7. The device of claim 1, wherein the collector is a conical cavity structure made of a material resistant to particle erosion, or a flat plate structure made of a material resistant to particle erosion.
8. The device for analyzing retarding energy of claim 1, wherein said inlet electrode, retarding electrode, insulating pad and collector are machined and said grid is machined by electrochemical etching or machining.
9. The device for analyzing retarding potential energy of claim 1, further comprising a grounded shielding housing for shielding the disturbance.

Description

Retarding potential energy analysis device Technical Field The invention relates to the technical field of space electric thrusters, in particular to a retarding potential energy analysis device. Background The energy distribution of heavy ions is an important characteristic of the plume of the electric thruster, and can indirectly reflect basic performances such as specific impulse of the electric thruster. Meanwhile, the beam of the thruster is radially sprayed out, so that the angle between the thruster and the spacecraft body determines that the plume can reach the sensitive surface of the spacecraft, and further the performance of the spacecraft is affected. Therefore, the spatial application of thrusters must solve the problem of plume-spacecraft compatibility, where heavy ion energy distribution is the most important evaluation parameter, and the blocking potential energy analyzer (RPA) is a common device used to measure plume heavy ion energy distribution. Meanwhile, as shown in fig. 1, in an electrospray thruster using ionic liquid as a propellant working medium, ions are extracted and accelerated to form ion beam current under the action of an external electric field with corresponding polarity, and the ions in the beam current have polydispersion and comprise monomers and ion clusters (dimers, trimers and even other polymers) which are crushed with certain probability to form new ion/ion clusters and neutral molecules under the action of an electric field between an extraction grid and an emitter. The control of the crushing rate of the ion clusters in the accelerating area has important significance for propellant selection and thruster optimization design, and the adoption of a blocking potential energy analyzer (RPA) for accurately measuring the energy of charged particles in the beam is an effective method for obtaining the crushing rate of the ion clusters. As shown in fig. 2, the conventional retardation potential energy analyzer (RPA) is a planar structure consisting of at least 4 planar gates and 1 collector. The grid I is suspended to reduce disturbance of RPA to plasma, the grid II is connected with negative bias voltage (V 2) to repel electrons in the plasma, the grid III is connected with scanning voltage (V 3) to selectively pass through ions, and the grid IV is connected with negative bias voltage to inhibit upstream electrons from reaching the collector and inhibit high-energy ions from bombarding the collector to generate secondary electrons. During measurement, RPA is placed in a beam, a blocking electric field perpendicular to the normal direction of the surface of the grid is established between the voltage on the grid III and the grid II, and only ions with energy E not less than q (V 3-V2) are allowed to pass through and finally reach a collector, wherein q represents the charge number of the ions. The bias voltage on the grid III is scanned, the current collected by the collector and the corresponding blocking grid scanning voltage form an I-V curve, and the ion energy distribution can be obtained by analyzing the curve. However, the beam of the electric thruster is radial, and has a certain divergence angle, so that the flying direction of the charged particles deviates from the normal direction of the outlet of the thruster. Whereas in the planar RPA configuration, the blocking electric field direction between the gates is the same as the gate normal direction. In actual measurement, after the charged particles enter the RPA, an included angle exists between the flight direction and the blocking electric field direction, the electric field can only block the velocity component of the charged particles along the electric field direction, and the velocity component of the charged particles perpendicular to the electric field direction is not changed. Therefore, the actual cutoff energy of the charged particles is related to the incident angle thereof, resulting in a measurement error related to the incident angle, and if the incident angle of each ion is known, the measurement result can be corrected, but the actual charged particle direction exhibits a certain distribution characteristic, and the incident direction thereof cannot be accurately measured. Considering that the electric field in the RPA is related to the grid configuration, as shown in fig. 3, a concentric spherical grid structure is present, and an electric field distribution pointing to the center of the grid can be formed between the grids, if the flight start position of the charged particles is located at the center of the grid, the incident direction of the charged particles will always be consistent with the direction of the blocking electric field, so that the error caused by beam divergence can be reduced or even eliminated. However, once the curvature of the spherical grid is determined, the distance between the spherical RPA and the initial position of the charged particle source (i.e., the measured