CN216902792U

CN216902792U - Uniform defocusing electron gun for space electron beam simulation device

Info

Publication number: CN216902792U
Application number: CN202123419469.3U
Authority: CN
Inventors: 牛文斗; 曹永升; 柴彦科; 赵杰; 马正军; 穆建中; 李小琴
Original assignee: Gansu Hongguang Electronic Co ltd
Current assignee: Gansu Hongguang Electronic Co ltd
Priority date: 2021-12-31
Filing date: 2021-12-31
Publication date: 2022-07-05
Anticipated expiration: 2031-12-31

Abstract

The utility model provides a uniform defocusing electron gun for a space electron beam simulating device, wherein a high-voltage ceramic component comprises: the high-voltage ceramic tube, the cathode lead rod, the filament lead rod, the cathode supporting seat, the high-voltage ceramic tube connecting flange and the cap sealing ring; the anode assembly includes: an anode ring, an anode ceramic cylinder, an anode lead and an anode sealing flange; the cathode assembly includes: the high-voltage ceramic lamp comprises an upper cathode cover, a lower cathode cover, a filament base I, a filament base II and a coiled filament, wherein a high-voltage ceramic cylinder is divided into an upper body and a lower body; the vacuum flange plate is connected with the high-pressure ceramic cylinder connecting flange by argon arc welding; the anode sealing flange is connected with the vacuum flange plate through screws; an anode lead is placed in a cavity inside the anode ceramic cylinder; a defocusing permanent magnet is fixed outside the anode ceramic cylinder; the upper part of the cathode cover and the lower part of the cathode cover are buckled and fixed with a grid mesh, and the end surface of the coiled filament is spaced from the grid mesh; the roughness of the outer surface of the cathode cover is less than or equal to 0.4. The effect is as follows: uniform defocusing and large defocusing section. Has good insulation, air tightness and firmness.

Description

Uniform defocusing electron gun for space electron beam simulation device

Technical Field

The utility model belongs to a simulated cosmic space electron beam irradiation device, and relates to an electron gun for irradiation.

Background

The high-energy electron beams from the universe space affect the surface materials of the spacecraft (such as artificial satellites, star finders, space stations and the like) and even affect the internal instruments and key components of the spacecraft. The spacecraft space electron beam shielding equipment is optimized and improved by researching the interaction between space electrons, the influence mechanism of electron beams on a spacecraft and quantitative electron beam intensity measurement, and a laboratory simulates the physical process by simulating a space electron beam irradiation device.

The electron beam model generated by the test device should be as close to the high-energy electron beam in the cosmic space as possible. For this reason, the quality of the performance of the electron gun, which is the main component in the test apparatus, determines to some extent the authenticity and reliability of the physical model formed. The existing electron beam irradiation gun has large volume and inconvenient carrying, and has the phenomenon of creepage and sparking under high voltage.

SUMMERY OF THE UTILITY MODEL

The utility model provides a uniform defocusing electron gun for a space electron beam simulating device, which is mainly applied to small-power portable electron beam irradiation equipment and aims to solve the problems in the background art.

The technical scheme of the utility model is as follows: the utility model provides a uniform defocusing electron gun for simulating space electron beam device, includes high-pressure ceramic subassembly, anode assembly, negative pole subassembly, vacuum flange dish, and the vacuum flange dish is standard vacuum flange, and wherein the high-pressure ceramic subassembly includes: the high-voltage ceramic tube, the cathode lead rod, the filament lead rod, the cathode supporting seat, the high-voltage ceramic tube connecting flange and the cap sealing ring; the anode assembly includes: an anode ring, an anode ceramic cylinder, an anode lead and an anode sealing flange; the cathode assembly includes: the high-voltage ceramic cylinder is divided into an upper body and a lower body which are respectively arranged on the upper side and the lower side of a high-voltage ceramic cylinder connecting flange, and the outer surface of the lower body of the high-voltage ceramic cylinder is corrugated; the vacuum flange plate is connected with a high-pressure ceramic cylinder connecting flange of the high-pressure ceramic component through argon arc welding; the anode sealing flange of the anode assembly is connected with the vacuum flange plate through a fixing screw; a defocusing permanent magnet is fixed outside the anode ceramic cylinder; a cavity is arranged in the anode ceramic cylinder, an anode lead is arranged in the cavity, the upper end of the anode lead penetrates through the anode ring, the lower end of the anode lead penetrates through the anode sealing flange, and the anode ring and the vacuum flange are connected together through the anode lead; the upper part of the cathode cover and the lower part of the cathode cover are buckled, a grid mesh is fixed at the buckling part, the coiled filament extends out of two legs which are respectively attached to the filament seat I and the filament seat II and are fixed with the filament seat I and the filament seat II through a pressing plate and screws, the end surface of the coiled filament is parallel to the upper end surface of the cathode cover, the pitch of the coiled filament is uniform, the size of the grid mesh is consistent, and a spacing distance is reserved between the end surface of the coiled filament and the grid mesh; the outer surfaces of the cathode cover and the cathode cover in the cathode assembly are polished surfaces, and the surface roughness is not higher than 0.4.

The grid mesh is a honeycomb hexagonal grid mesh.

The cathode assembly adopts a directly-heated pure tungsten cathode.

The cathode assembly and the high-voltage ceramic assembly are connected together through screws.

Preferably, the distance between the end face of the coiled-coil filament and the grid is 0.3-0.5 mm.

The anode ceramic cylinder and the anode sealing flange are in a step type matching structure.

The utility model has the beneficial effects that: and a standard vacuum flange is adopted, so that the device is convenient to be matched with equipment for use. The filament can conveniently be changed among the negative pole subassembly, and to a great extent reduces use cost. And a control electrode of the cathode component, namely a cathode cover, focuses the electron beam, defocuses the electron beam through the defocusing permanent magnet, and accelerates the electron beam through an accelerating electric field provided by the anode ring to form an electron beam with electron energy of 40-60 keV, laminar flow, uniform defocusing and large defocusing section. The metal ceramic structure is adopted, so that the metal ceramic material has the characteristics of good insulativity, air tightness and firmness, uniform electron beam emission, convenience in maintenance and replacement and the like, and is widely applied to the related fields of electron beam irradiation, scientific research and the like. The ceramic surface is polished, and the creepage and sparking phenomena do not exist under high pressure. On the basis of ensuring the performance of the electron gun, the electron beam current generating device generates the electron beam current with stable electron beam current intensity and large defocusing area by adopting the pure metal cathode, the honeycomb metal grid mesh and the defocusing permanent magnet, and provides guarantee for the accuracy of scientific experiments.

Drawings

FIG. 1 is an assembly view of an embodiment of the present invention;

FIG. 2 is a diagram of a high pressure ceramic assembly according to an embodiment of the present invention;

FIG. 3 is a diagram of an anode assembly according to an embodiment of the present invention;

FIG. 4 is a diagram of a cathode assembly according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of a grid in accordance with an embodiment of the present invention;

fig. 6 is a schematic view of a coiled coil filament according to an embodiment of the present invention.

Description of reference numerals: 11-a high voltage ceramic component; 12-an anode assembly; 13-cathode assembly diagram; 14-vacuum flange; 111-high pressure ceramic cylinder; 112-cathode lead bar; 113-filament lead rods; 114-cathode support base; 115-high-voltage porcelain cylinder connecting flange; 116-cap sealing ring; 121-anode ring; 122-anode ceramic cylinder; 123-anode lead; 124-anode sealing flange; 125-defocused permanent magnet; 131-cathode cover; 132-under the cathode cap; 133-filament seat I; 134-filament base II; 135-a grid; 136-coil type filament; 137-filament base insulating ceramic plate; 15-set screw.

Detailed Description

The utility model will be further explained with reference to the drawings.

As shown in the figure, a uniform defocusing electron gun for a device simulating a space electron beam current comprises a high-voltage ceramic component 11, an anode component 12, a cathode component 13 and a vacuum flange 14, wherein the vacuum flange 14 is a standard vacuum flange, wherein the high-voltage ceramic component 11 comprises: a high-voltage ceramic cylinder 111, a cathode lead rod 112, a filament lead rod 113, a cathode support seat 114, a high-voltage ceramic cylinder connecting flange 115 and a cap sealing ring 116; the anode assembly 12 includes: an anode ring 121, an anode ceramic cylinder 122, an anode lead 123, an anode sealing flange 124 and a defocusing permanent magnet 125; the cathode assembly 13 includes: the cathode comprises a cathode cover upper 131, a cathode cover lower 132, a filament base I133, a filament base II 134, a grid 135 and a coiled filament 136.

The vacuum flange plate 14 adopts a standard vacuum flange which is used as a medium for vacuum connection with equipment, so that the vacuum flange plate is convenient to replace integrally or individually; the high-voltage ceramic cylinder 111 is made of corrugated porcelain, and the stability of the electron gun is ensured to be between 50kV and 100 kV.

The cathode assembly 13 is connected with the high-voltage ceramic assembly 11 through a screw, so that the disassembly and the maintenance are convenient; the current density required by the analog space electron beam device is generally in a grade of nA to muA, and the input power of the filament is not too large, so that the temperature of a cathode component is too high, and the performance of an electron gun is influenced.

The vacuum flange plate 14 and the high-pressure ceramic cylinder connecting flange 115 of the high-pressure ceramic component 11 are connected together through argon arc welding, so that good air tightness and mechanical strength are ensured.

The vacuum flange 14 is connected to the anode assembly 12 by means of fixing screws 15, which on the one hand facilitate the removal of the anode assembly and on the other hand provide conditions for grounding the anode.

An anode lead 123 in the wall of the anode ceramic cylinder 122 connects the anode ring 121 and the vacuum flange 14, and places the anode ring 121 at a ground zero potential to form an electron accelerating electric field with the negative high voltage of the cathode assembly 13.

The magnetic induction intensity of the defocusing permanent magnet 125 is at least 0.5-0.8T. The defocusing permanent magnet is not too close to the filament so as to avoid excessive scattering of electrons and serious influence on the laminar flow of the electron beam, and the thickness of the defocusing permanent magnet is generally kept between 15 mm and 20 mm; too far away results in poor defocusing.

A hexagonal grid 135 is assembled in the cathode assembly 13 and fixed by a cathode cover upper 131 and a cathode cover lower 132, and the grid with the corresponding size can be replaced according to the actual current density; meanwhile, the openings of the grid mesh are uniform, and high-temperature resistant materials (such as molybdenum) are generally adopted. The processed thickness of the grid is 0.5mm in consideration of heat conduction and strength.

The distance between the coiled-coil-type filament 136 and the grid 135 in the cathode assembly 13 is kept between 0.3 mm and 0.5mm, the height of the distance can be adjusted according to actual use test conditions, and the end face of the coiled-coil-type filament 136 before and after adjustment is ensured to be parallel to the end face of the cathode cover upper 131.

Coil odor type filament 136 stretches out two legs, and two legs are laminated respectively on filament seat I133 and filament seat II 134 to it is fixed mutually with two legs and filament seat I, filament seat II through clamp plate and screw, and this kind of mechanical system installation, the convenient change, the filament coiling becomes mosquito odor type, provides circular cross-section electron beam. The grid mesh at the upper end of the cathode improves the laminar flow of the electron beam to a great extent. The cathode cover 131 of the cathode assembly focuses the electron beam first, providing conditions for uniform defocusing of the defocused permanent magnet and acceleration of electrons by the anode ring. In order to ensure the safety and the beauty of the anode assembly, the anode lead is arranged inside the anode ceramic cylinder, and the motion trail of the electron beam is ensured under the condition of not influencing the electric field distribution of the cathode and the anode as far as possible.

Because the electron irradiation equipment can work for a long time, in addition, the grid net for adjusting the laminar flow property of the electron beam is arranged at the upper end of the cathode, a large amount of electrons can return to the surface of the cathode, if a reserve cathode (such as a barium-tungsten cathode, an oxide cathode and the like) is adopted, although the emission current density is high, the working condition is harsh, a high vacuum environment is required at any moment, the anti-return capability is poor, the electron beam density in the space is very small, the requirement on the emission current of an electron gun is very small, and the consumption of the grid net is considered, so that the emission requirement is generally 0.5-1 mA. Meanwhile, in order to facilitate replacement and save cost, the cathode of the utility model adopts a direct-heating pure tungsten cathode. Because the cathode emission current is very small, the influence of the generated heat radiation on other parts of the electron gun is small when the cathode works, and the working stability and the service life of the electron gun are ensured.

The utility model comprises the following steps: first, the high voltage ceramic assembly 11 and the anode assembly 12 are sealed.

The specific steps for sealing the high-voltage ceramic component 11 in this example are:

1) in order to reduce the stress between the high-voltage ceramic cylinder 111 and the cathode support seat 114 during sealing, the high-voltage ceramic cylinder 111 is divided into an upper body and a lower body which are respectively arranged on the upper side and the lower side of a high-voltage ceramic cylinder connecting flange 115;

2) the sealing is finished in two steps: firstly, assembling a lower half part of a high-voltage ceramic cylinder 111, a cathode lead rod 112, a filament lead rod 113, a cathode supporting seat 114 and a cap sealing ring 116 according to the position shown in figure 2, and placing pure silver welding wires at positions A2, A3, A4 and A5 shown in figure 2;

3) placing the silver solder into a hydrogen furnace, slowly raising the temperature to 960 ℃, preserving the heat for 8 minutes, then reducing the temperature to normal temperature, melting the pure silver solder wire into connection seal, and taking out the pure silver solder wire for leak detection;

4) assembling the assembly welded in the step 3) with the high-pressure ceramic cylinder connecting flange 115 and the upper half part of the high-pressure ceramic cylinder 111 according to the method shown in fig. 2, placing a pure silver welding wire at a position A1 shown in fig. 2, and welding a position A1 according to the method described in the step 3), namely, completing the welding of the whole high-pressure ceramic assembly 11.

The steps for sealing the anode assembly 12 in this example are:

the anode lead 123 is placed into the cavity of the anode ceramic cylinder 122, the step at the bottom of the anode ceramic cylinder 122 is closely attached to the step of the anode sealing flange 124, the upper part of the anode ceramic cylinder 122 is closely attached to the anode ring 121, the upper end of the anode lead 123 penetrates through the anode ring 121, and the lower end of the anode lead 123 penetrates through the anode sealing flange 124. The gaps between the components of the anode assembly 12 are also welded by pure silver welding wires in a melting way, so that the sealing effect is achieved.

The cathode assembly 13 in this example is assembled mechanically as shown in figure 4. The filament base II 134 is sleeved with the cathode cover lower 132 through threads, the cathode cover lower 132 is sleeved with the cathode cover upper 131 through threads, the coiled filament 136 is pressed and fixed by the cathode cover lower 132 and the cathode cover upper 131, and the filament base insulating porcelain plate 137 is sleeved with the filament base I133.

It should be noted that the pitch of the coil-type filament 136 in the cathode assembly 13 must be uniform to ensure uniform current density and an effective emitting surface.

The grid size of the grid 135 must be consistent to ensure good electron beam laminar flow.

The outer surfaces of the upper 131 and lower 132 cathode covers of the cathode assembly 13 must be polished to a surface roughness of 0.4 or less to ensure that the electron gun does not ignite when operating under a DC high voltage.

The three parts of components are assembled by referring to fig. 1, and the high-pressure porcelain cylinder connecting flange 115 and the vacuum flange 14 are connected by argon arc welding, so that all assembling processes of the electron gun are completed.

Claims

1. A uniform defocusing electron gun for a device simulating a space electron beam current comprises a high-voltage ceramic component (11), an anode component (12), a cathode component (13) and a vacuum flange plate (14), wherein the vacuum flange plate (14) is a standard vacuum flange, and the high-voltage ceramic component (11) comprises: the high-voltage ceramic lamp comprises a high-voltage ceramic cylinder (111), a cathode lead rod (112), a filament lead rod (113), a cathode support seat (114), a high-voltage ceramic cylinder connecting flange (115) and a cap sealing ring (116); the anode assembly (12) includes: an anode ring (121), an anode ceramic cylinder (122), an anode lead (123) and an anode sealing flange (124); the cathode assembly (13) comprises: the negative pole covers (131), under the negative pole lid (132), filament seat I (133), filament seat II (134), coiled incense type filament (136), characterized by: the high-pressure ceramic cylinder (111) is divided into an upper body and a lower body which are respectively arranged on the upper side and the lower side of the high-pressure ceramic cylinder connecting flange (115), and the outer surface of the lower body of the high-pressure ceramic cylinder (111) is corrugated; the vacuum flange plate (14) is connected with a high-pressure ceramic cylinder connecting flange (115) of the high-pressure ceramic component (11) through argon arc welding; the anode sealing flange (124) of the anode assembly (12) is connected with the vacuum flange plate (14) through a connecting piece; a defocusing permanent magnet (125) is fixed outside the anode ceramic cylinder (122); a cavity is arranged in the anode ceramic cylinder (122), an anode lead (123) is arranged in the cavity, the upper end of the anode lead (123) penetrates through the anode ring (121), the lower end of the anode lead (123) penetrates through the anode sealing flange (124), and the anode ring (121) and the vacuum flange plate (14) are connected together through the anode lead (123); the upper cathode cover (131) and the lower cathode cover (132) are buckled and fixed with a grid mesh (135) at the buckling position, the coiled filament (136) is fixed on the filament seat I (133) and the filament seat II (134), the end surface of the coiled filament (136) is parallel to the end surface of the upper cathode cover (131), the thread pitch of the coiled filament (136) is uniform, the size and the dimension of grids of the grid mesh (135) are consistent, and a spacing distance is reserved between the end surface of the coiled filament (136) and the grid mesh (135); the outer surfaces of the upper cathode cover (131) and the lower cathode cover (132) in the cathode assembly (13) are polished surfaces, and the surface roughness is not higher than 0.4.

2. A uniform defocusing electron gun for an analog space electron beam current device, as claimed in claim 1, wherein: the grid mesh (135) is a honeycomb hexagonal grid mesh.

3. A uniform defocusing electron gun for an analog space electron beam current device, as claimed in claim 1, wherein: the cathode component (13) adopts a direct heating type pure tungsten cathode.

4. A uniform defocusing electron gun for an analog space electron beam current device, as claimed in claim 1, wherein: the cathode assembly (13) and the high-voltage ceramic assembly (11) are connected together through screws.

5. A uniform defocusing electron gun for an analog space electron beam current device, as claimed in claim 1, wherein: the distance between the end face of the coiled filament (136) and the grid mesh (135) is 0.3-0.5 mm.

6. A uniform defocusing electron gun for an analog space electron beam current device, as claimed in claim 1, wherein: the anode ceramic cylinder (122) and the anode sealing flange (124) are in a step-type matching structure.

7. A uniform defocusing electron gun for an analog spatial electron beam current device, as defined in claim 1, wherein: the magnetic induction intensity of the defocusing permanent magnet (125) is 0.5-0.8T, and the vertical distance between the defocusing permanent magnet (125) and the coiled filament (136) is 15-20 mm.

8. A uniform defocusing electron gun for an analog spatial electron beam current device, as defined in claim 1, wherein: the thickness of the grid mesh (135) is 0.5 mm.