CN110196362A - The test macro and method of electron gun emitting performance - Google Patents

Abstract

An electron gun emission performance testing system and method, the system includes: a first vacuum chamber, a second vacuum chamber, a vacuum system, an electrode system and an electrical control system; the first vacuum chamber and the second vacuum chamber are used for placing electron guns, wherein the first vacuum chamber and the second vacuum chamber The vacuum chamber is provided with an anode; the vacuum system is used to evacuate the first vacuum chamber and the second vacuum chamber; the electrode system is used to provide current and voltage for the electron gun; the electrical control system is used to control the action of the vacuum system and the electrode system, To test the gun firing performance of electrons. The system has the advantages of compact structure, high reliability, and complete measurement parameters, which can effectively shorten the development cycle of electron guns and microwave tubes, and is convenient for mass production applications.

Description

Test system and method for electron gun launch performance

technical field

The invention relates to the technical field of vacuum electronics, in particular to a system and method for testing the emission performance of an electron gun.

Background technique

The electron gun is the heart of the microwave tube, which is composed of the cathode-thermal subassembly, the cathode support cylinder, the control electrode and the hot sub-lead assembly, etc. Its function is to generate and form a certain shape of electron injection. In the process of microwave tube development, the assembly and welding accuracy of electron gun components can be tested by contact or non-contact measurement methods to determine whether the geometry of the electron gun is qualified; It can be verified in the thermal measurement link after the whole tube is formed. If the electrical performance index of the electron gun is unqualified, the whole tube can only be reworked, and the process parameters are adjusted to prepare the electron gun assembly again. There are two main problems faced by the electron gun during the development of the microwave tube: First, the expansion of the electron gun's focusing pole determines the distance between the cathode and the anode. The larger or smaller distance will affect the emission performance of the electron gun and the electrical performance of the entire tube. . At present, the distance is calculated based on the amount of expansion, and the working state of the cathode and anode cannot be simulated. Second, there is no relevant means to test the cathode emission performance and conductance coefficient of the electron gun before forming the whole tube, and the emission current of the electron gun cathode is large or small. The electron gun in the tube fires. In order to ensure the reliability and stability of the microwave tube, it is necessary to test the emission performance of the electron gun.

SUMMARY OF THE INVENTION

(1) Technical problems to be solved

In view of the existing technical problems, the present invention provides a system and method for testing the emission performance of an electron gun, which are used to solve the problem of simulating the working state of the cathode-anode in the prior art and testing the emission performance of the electron gun and the conductivity coefficient before forming the whole tube. Unmeasured problem.

(2) Technical solutions

The invention provides an electron gun emission performance testing system, comprising: a first vacuum chamber, a second vacuum chamber, a vacuum system, an electrode system and an electrical control system; the first vacuum chamber and the second vacuum chamber are used for placing the electron gun, wherein the first vacuum chamber and the second vacuum chamber are used for placing the electron gun. The vacuum chamber is provided with an anode; the vacuum system is used to evacuate the first vacuum chamber and the second vacuum chamber; the electrode system is used to provide current and voltage for the electron gun; the electrical control system is used to control the action of the vacuum system and the electrode system to test The gun firing performance of electrons.

Optionally, the vacuum system includes an ion pump 1, a mechanical pump 59, a molecular pump 60 and a vacuum pipeline 3; the air inlet of the ion pump 1 is connected to the first vacuum chamber; the air inlet of the mechanical pump 59 is connected to the air outlet of the molecular pump 60 , the air inlet of the molecular pump 60 is connected to the second vacuum chamber; the air inlet of the molecular pump 60 is connected with the air inlet of the ion pump 1 through the vacuum pipe 3 .

Optionally, the vacuum pipeline 3 includes a first port, a second port, a third port and a fourth port; the air inlet of the ion pump 1 is connected to the first port, and the second port is connected to the first vacuum chamber; The gas port is connected to the fourth port, and the third port is connected to the second vacuum chamber.

Optionally, the electrode system includes a first electrode 8 , a second electrode 10 and a third electrode 22 , one end of the three electrodes is connected to the vacuum system, and the other end is connected to the electrical control system.

Optionally, the first port and the second port are on the same vertical line, and the third port and the fourth port are on the same vertical line.

Optionally, the vacuum system further includes a first pneumatic high vacuum baffle valve 4, a second pneumatic high vacuum baffle valve 9, a third pneumatic high vacuum baffle valve 23, a fourth pneumatic high vacuum baffle valve 30, a fifth pneumatic high vacuum baffle valve 30, and a fifth pneumatic high vacuum baffle valve. Pneumatic high vacuum flapper valve 35, three-way connecting pipe 36, blind flange 37, sixth pneumatic high vacuum flapper valve 38, seventh pneumatic high vacuum flapper valve 39, vacuum connection pipe 40 and third bellows 41 The air inlet of the mechanical pump 59 is connected with the air outlet of the molecular pump 60 through the fifth pneumatic high vacuum baffle valve 35, the three-way connecting pipe 36 and the third bellows 41; The vacuum baffle valve 35 and the vacuum connecting pipe 40 are connected with the sixth pneumatic high vacuum baffle valve 38 and the seventh pneumatic high vacuum baffle valve 39; the blind flange 37 is arranged beside the fourth port.

Optionally, a first flapper valve 2 is arranged between the air inlet of the ion pump 1 and the first port, and a second flapper valve 7 is arranged between the second port and the first vacuum chamber; A fourth plug valve 31 is provided between the air port and the fourth port, and a third plug valve 24 is provided between the third port and the second vacuum chamber.

Optionally, the electron gun emission performance testing system also includes a vacuum gauge 42, a first resistance gauge 34, a second resistance gauge 61 and an ionization gauge 62; the first resistance gauge 34 is connected to the vacuum gauge 42 for measuring the intake air of the mechanical pump 59. The vacuum degree of the mouth; the second resistance gauge 61 is connected to the vacuum gauge 42 for measuring the low vacuum degree of the first vacuum chamber and the second vacuum chamber; the ionization gauge 62 is connected to the vacuum gauge 42 for measuring the first vacuum chamber and the second vacuum chamber. High vacuum of the second vacuum chamber.

Optionally, the starting condition of the ion pump is that the vacuum degree of the air inlet is better than 5×10 ^-4 Pa, and the starting condition of the molecular pump is that the vacuum degree of the air inlet is not lower than 10 Pa.

Another aspect of the present invention provides a method for testing the emission performance of an electron gun. In the chamber, the electrode of the electron gun is connected with the electrode of the system; S3, start the mechanical pump, open the second, third and fourth pneumatic high-vacuum flapper valves, and wait until the vacuum degree of the air inlet of the mechanical pump is better than the first preset value , start the molecular pump, and open the second, third, and fourth plug-in valves connected to the molecular pump; S4, when the vacuum degree of the air inlet of the molecular pump is better than the second preset value, open the first plug-in valve; S5, The electron gun is heated, and the emission current, conductivity coefficient and surface temperature of the electron gun are tested.

(3) Beneficial effects

The present invention provides a system and method for testing the emission performance of an electron gun, and the beneficial effects are as follows:

(1) The performance testing system and method obtain ultra-high vacuum through a vacuum system and an electrical system, and the ultimate vacuum degree is better than 2×10 ^-7 Pa.

(2) The performance testing system and method can conveniently and quickly test the emission performance of the electron gun, effectively shorten the development cycle of the electron gun and the microwave tube, and improve the reliability and stability of the electron gun;

(3) The performance testing system and method can test the temperature, voltage and other experimental data of the electron gun under different currents and times to provide a basis for the subsequent procedures of the microwave tube;

(4) The double-station test system has a compact structure, small footprint, convenient operation, and is convenient for mass production applications.

Description of drawings

FIG. 1 schematically shows a schematic diagram of a system for testing the emission performance of a microwave tube electron gun according to an embodiment of the present invention.

FIG. 2 schematically shows a right side view of a microwave tube electron gun emission performance testing system according to an embodiment of the present invention.

FIG. 3 schematically shows a schematic diagram of an electrical control system in a microwave tube electron gun emission performance testing system according to an embodiment of the present invention.

FIG. 4 schematically shows a flow chart of a method for testing the emission performance of a microwave tube electron gun according to an embodiment of the present invention.

[reference number]

1-Ion pump; 2-The first flapper valve; 3-Vacuum pipeline;

4-The first pneumatic high vacuum flapper valve; 5-The first clamp; 6-The first three-way;

7--the second flapper valve; 8--the first electrode; 9--the second pneumatic high-vacuum flapper valve;

10-Second electrode; 11-Water-cooled anode; 12-Lifting mechanism;

13-The first observation window CF63; 14-Stainless steel bell jar; 15-The second observation window CF63;

16-bracket; 17-knife flange CF150; 18-quartz bell;

19-material tray; 20-rubber sealing ring; 21-bench;

22-The third electrode; 23-The third pneumatic high vacuum flapper valve; 24-The third flapper valve;

25-reducer pipe; 26-second tee; 27-first corrugated pipe; 28-second clamp;

29-The third clamp; 30-The fourth pneumatic high vacuum flapper valve;

31- the fourth plug valve; 32- elbow; 33- the second bellows;

34- The first resistance gauge; 35- The fifth pneumatic high vacuum flapper valve; 36- Three-way connecting pipe;

37-blind flange; 38-sixth pneumatic high vacuum flapper valve;

39-the seventh pneumatic high vacuum flapper valve; 40-vacuum connecting pipe; 41-the third bellows;

42-vacuum gauge; 43-cabinet; 44-display; 45-bell rise button;

46-bell jar down button; 47-bell jar release button; 48-compressed air abnormal button;

49- Vacuum abnormal button; 50- Water shortage button; 51- Molecular pump abnormal button;

52-Mechanical pump abnormal button; 53-Alarm reset button; 54-First filament power supply;

55-second filament power supply; 56-high voltage power supply; 57-ion pump power supply;

58-UPS power supply; 59-Mechanical pump; 60-Molecular pump; 61-Second resistance gauge; 62-Ionization gauge.

Detailed ways

The invention provides a microwave tube electron gun emission performance testing system and method, which has the advantages of compact structure, high reliability, and complete measurement parameters, and can effectively shorten the development cycle of the electron gun and the microwave tube.

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

An embodiment of the present invention provides an electron gun emission performance testing system, including:

The first vacuum chamber, the second vacuum chamber, the vacuum system, the electrode system and the electrical control system.

The first vacuum chamber and the second vacuum chamber are used to place the electron gun, wherein the first vacuum chamber is provided with an anode; the vacuum system is used to evacuate the first vacuum chamber and the second vacuum chamber; the electrode system is used to provide current and voltage for the electron gun ; The electrical control system is used to control the action of the vacuum system and the electrode system, so as to realize the test of the gun emission performance of the electrons placed in the two vacuum chambers. The schematic diagram of the specific structure is shown in Figure 1 and Figure 2 .

1 and FIG. 2, a first vacuum chamber (stainless steel bell 14) and a second vacuum chamber (quartz bell 18) are symmetrically arranged on the stainless steel work surface of the stand 21. The stainless steel bell 14 is connected with the lifting mechanism 12 to realize the lifting of the bell; the electron gun and the water-cooled anode 11 form an electron gun performance test structure to simulate the working state of the cathode-anode; the first observation window 13 and the second observation window 15 realize the internal Observation; the stainless steel bell 14 is installed and removed for maintenance through the bracket 16 ; vacuum sealing is achieved through the knife-edge flange 17 .

The quartz bell 18 is sealed and connected with the lower worktable by an L-shaped fluororubber sealing ring 20 to form a sealed worktable. A vacuum pipe 3 and an electrode terminal are arranged below the workbench, which are used for vacuum connection between the workbench and the vacuum system, and electrical connection with the electrode system. The quartz bell 18 is required to withstand a certain pressure and temperature, so the main body is an upright cylindrical revolving body, the bottom port is a circular plane, and the top is a hemisphere. The material tray 19 is placed inside the quartz bell for installation and fixation of the electron gun.

The vacuum system includes: an ion pump 1 , a mechanical pump 59 , a molecular pump 60 , a valve and a vacuum pipeline 3 . The ion pump 1 is located at the lower part of the workbench of the stainless steel bell 14 , and the molecular pump 60 is located at the lower part of the workbench of the quartz bell 18 .

The air inlet of the mechanical pump 59 is connected to the air outlet of the molecular pump 60 ; the air inlet of the molecular pump 60 is connected to the workbench of the quartz bell 18 . The air inlet of the ion pump 1 is connected to the stainless steel bell 14 table. The air inlet of the molecular pump 60 and the air inlet of the ion pump 1 are connected through the vacuum pipe 3 . In actual work, the corresponding vacuum pump can be turned on as required to evacuate the stainless steel bell 14 and the quartz bell 18 .

The vacuum pipe 3 is an "H" type vacuum pipe. The air inlet of the ion pump 1 is connected to the first port of the vacuum pipeline 3 through the first flapper valve 2 , and the second port of the vacuum pipeline 3 is connected to the stainless steel bell 14 workbench via the second flapper valve 7 . Wherein, the first port and the second port are ports on the same vertical line.

The air inlet of the molecular pump 60 is connected to the fourth port of the vacuum pipe 3 through the fourth plug valve 31 . The third port of the vacuum pipe 3 is connected to the workbench of the quartz bell 18 through the third plug valve 24 . Wherein, the third port and the fourth port are ports on the same vertical line.

The first plug valve 2, the second plug valve 7, the third plug valve 24 and the fourth plug valve 31 are all pneumatic ultra-high vacuum plug valve. When the stainless steel bell workbench works independently, open the first plug valve 2, the second plug valve 7 and the fourth plug valve 31; when the quartz bell workbench works independently, open the first plug valve 2 and the third plug valve 31. Plate valve 24 and fourth plate valve 31; when the two workbenches work at the same time, open the first plate valve 2, the second plate valve 7, the third plate valve 24 and the fourth plate valve 31.

Further, the vacuum system also includes: a first pneumatic high vacuum baffle valve 4, a second pneumatic high vacuum baffle valve 9, a third pneumatic high vacuum baffle valve 23, a fourth pneumatic high vacuum baffle valve 30, a fifth pneumatic high vacuum baffle valve 30, and a fifth pneumatic high vacuum baffle valve 30. Pneumatic high vacuum flapper valve 35, three-way connecting pipe 36, blind flange 37, sixth pneumatic high vacuum flapper valve 38, seventh pneumatic high vacuum flapper valve 39, vacuum connection pipe 40 and third bellows 41 . The air inlet of the mechanical pump 59 is connected to the air outlet of the molecular pump 60 through the fifth pneumatic high vacuum baffle valve 35, the three-way connecting pipe 36 and the third bellows 41; the air inlet of the mechanical pump 59 is connected to the air outlet of the molecular pump 60 through the fifth pneumatic high vacuum The flapper valve 35 and the vacuum connection pipe 40 are connected to the sixth pneumatic high vacuum flapper valve 38 and the seventh pneumatic high vacuum flapper valve 39 . The blind flange 37 is arranged near the fourth port of the vacuum pipeline 3 to achieve vacuum sealing and can be used for expanding the interface.

Mechanical pump 59, second bellows 33, first resistance gauge 34, tee connecting pipe 36, first bellows 27, first tee 6, second tee 26, clamps 5, 28, 29, elbow 32, reducing pipe 25, first pneumatic high vacuum flapper valve 4, fifth pneumatic high vacuum flapper valve 35, sixth pneumatic high vacuum flapper valve 38, seventh pneumatic high vacuum flapper valve 39, vacuum connecting pipe 40. The second pneumatic high vacuum baffle valve 9, the third pneumatic high vacuum baffle valve 23, and the fourth pneumatic high vacuum baffle valve 30 are respectively connected with the two workbenches to form the bypass system of the vacuum system. The opening and closing of the vacuum baffle valve realizes the pre-evacuation and vacuum release of the two workbenches.

The electrode system is arranged under the stage 21 and corresponds to the first electrode 8 , the second electrode 10 and the third electrode 22 of the stage electrodes. The microwave tube electron gun placed on the workbench is electrically connected to the corresponding electrodes under the workbench. The front end of the three electrodes is connected to the vacuum system, and the back end is connected to the electrical control system to provide current and voltage for the microwave tube electron gun in a vacuum state.

The electron gun emission performance testing system is also provided with an ionization gauge 62 and a second resistance gauge 61, and the degree of vacuum of the vacuum system is measured through the conversion of the four plug-in valves. The two workbenches can work independently or at the same time, and after one workbench is aerated, the vacuum degree of the other is not less than 6×10 ^-6 Pa.

3, the electrical control system is a PLC control system, and the cabinet 43 is provided with a composite vacuum gauge 42, a display screen 44, a bell up button 45, a bell down button 47, a first filament power supply 54, and a second filament power supply 55. High voltage power supply 56, ion pump power supply 57, UPS power supply 58, in order to prevent misoperation, the cabinet 43 is equipped with fault prompt buttons, including compressed air abnormal button 48, vacuum abnormal button 49, water shortage button 50, molecular pump abnormal button 51, the mechanical pump abnormal button 52, and the alarm reset button 53. Mechanical pump 59, molecular pump 60, pneumatic high vacuum flapper valve, flapper valve, ion pump power supply 57, electron gun filament power supply 54 and 55, high voltage power supply 55, UPS power supply 58, compound vacuum gauge 42, bell lift button 45, Bell down button 46, bell release button 47, compressed air abnormal button 48, vacuum abnormal button 49, water shortage button 50, molecular pump abnormal button 51, mechanical pump abnormal button 52, and alarm reset button 53 all pass through the control circuit Connect with the electrical control system.

The molecular pump power supply and the molecular pump 60 are connected to the electrical control system for controlling the startup and shutdown of the molecular pump 60; the ion pump power supply 57 is connected to the ion pump 1 for controlling the startup and shutdown of the ion pump 1, wherein the startup of the ion pump The conditions are that the degree of vacuum is better than 5×10 ^-4 Pa, and the vacuum pipes and vacuum chambers are fully baked and degassed; two sets of filament power sources 54, 55 and high-voltage power sources 56 are respectively connected to the electrodes, and control the two workbenches respectively. The current and voltage of the electron gun.

The composite vacuum gauge 42 is connected to the first resistance gauge 34 , the second resistance gauge 61 and the ionization gauge 62 for monitoring the vacuum degree of the vacuum system. In order to measure low vacuum and high vacuum at the same time, the vacuum gauge adopts a composite vacuum gauge. The first resistance gauge 34 is used to measure the vacuum degree of the air inlet of the mechanical pump 59 to meet the start-up requirements of the molecular pump 60 .

The second resistance gauge 61 and the ionization gauge 62 are respectively connected to the vacuum line 3 . Wherein, the second resistance gauge 61 is connected to the vacuum gauge 42, and is used to measure the vacuum degree (10 ⁵ Pa to 1×10 ^-1 Pa) of the two workbenches when the vacuum is low. The ionization gauge 62 is connected to the vacuum gauge 42, and is used for measuring the vacuum degree (1×10 ^-1 Pa to 2×10 ^-7 Pa) of the two workbenches under high vacuum.

The two workbenches share a set of digital vacuum gauge 42 , a mechanical pump 59 and its power supply, a molecular pump 60 and its power supply, and an ion pump 1 and its power supply 57 .

The abnormality 51 of the molecular pump is related to the vacuum degree. When the vacuum degree is lower than 10 Pa, the molecular pump power supply does not allow the molecular pump 60 to start.

The filament power supply is related to the vacuum degree. When the vacuum degree is lower than 3.0×10 ^-4 Pa, the filament current remains constant; when the vacuum degree is higher than 3.0×10 ^-4 Pa, the filament current value gradually increases.

Through the setting of the vacuum degree startup conditions such as the above-mentioned ion pump 1 and molecular pump 60, the microwave tube electron gun emission performance test system can obtain ultra-high vacuum through the vacuum system and electrical system, and the ultimate vacuum degree is better than 2 × 10 ^-7 Pa, and the measurement is reliable. Sex is high. By designing two stations, not only the emission performance and conductivity of the electron gun can be tested, but also the temperature of the electron gun under different currents and times. All measurement parameters. Through the design of the two-station symmetrical structure and the design of the connection between each device, the system has a compact structure, small footprint, convenient operation, and is convenient for mass production.

Based on the above-mentioned microwave tube electron gun emission performance testing system, another embodiment of the present invention proposes a method for testing the emission performance of an electron gun. The method is based on the simultaneous operation of two stations. The process is shown in Figure 4, including:

S1, close all flapper valves, and open the first pneumatic high vacuum flapper valve.

Before performing the performance test, it is necessary to check whether the water circuit and circuit of the system are normal. If all the flapper valves (2, 7, 24, 31) are normally closed, and the first pneumatic high vacuum flapper valve 4 is opened, the vacuum system will be vented. , open the bell jar on the station.

S2, place the electron gun in the bell jar, connect the two poles of the electron gun filament to the electrodes respectively, pay attention to tighten the wiring, cover the bell jar, and close the first pneumatic high vacuum baffle valve 4.

S3 , start the mechanical pump 59 , and open the second pneumatic high vacuum flapper valve 9 , the third pneumatic high vacuum flapper valve 23 and the fourth pneumatic high vacuum flapper valve 30 . When the vacuum degree of the air inlet of the mechanical pump 59 is better than the first preset value (for example, 10Pa), turn on the power supply of the molecular pump 60 and start it, and open the fourth plug valve 31, the second plug valve 7 and the first plug valve 31 connected to the molecular pump 60. Three-plate valve 24.

S4, the molecular pump 2 works normally, and when the vacuum degree of the air inlet of the molecular pump 60 is better than the second preset value (for example, 2.0× ^{10 −3 Pa} ), open the first plug valve 2 connected to the ion pump, and start the ion pump 1.

S5, heating the electron gun, and testing the emission current, conductivity coefficient and surface temperature of the electron gun.

When the vacuum degree in the vacuum chamber is better than 3.0×10 ^-4 Pa, press the "ON" button of the heating power to start heating the electron guns on the two stations, the electron guns are heated slowly, and the vacuum degree is better than 1×10 ^-4 Pa The current is gradually applied to 1A-2A, and the vacuum gauge shows that the vacuum degree of the system is better than 2 × 10 ^-4 Pa during the heating process of the component. During the heating process of the electron gun, performance tests such as electron gun emission current, conductivity coefficient and surface temperature can be carried out. At the same time, the electron gun can be degassed by vacuum to fully remove the gas and volatile substances adsorbed on the surface and inside of the two-station electron gun; after the electron gun is heated, turn the filament current knob to "0", and the test process is over.

After the test, close the plug valve connected to the ion pump and molecular pump, and then press the "stop" button of the ion pump and molecular pump. valve.

In addition, it should be noted that, in the accompanying drawings or the text of the description, the implementations that are not shown or described are in the form known to those of ordinary skill in the art, and are not described in detail. In addition, the above definitions of each element and method are not limited to various specific structures, shapes or manners mentioned in the embodiments, and those of ordinary skill in the art can simply modify or replace them, for example:

(1) The mechanical pump can be replaced by a dry pump;

(2) The pneumatic high vacuum flapper valve can be replaced by a manual high vacuum metal angle valve;

(3) The plug-in valve can be replaced by the ultra-high vacuum plug-in valve by hand;

(4) Directional terms mentioned in the embodiments, such as "up", "down", "front", etc., only refer to the directions of the drawings, and are not used to limit the protection scope of the present invention.

In summary, the present invention provides a system and method for testing the emission performance of a microwave tube electron gun with a dual-station worktable, which has the advantages of compact structure, high reliability, and complete measurement parameters, and can effectively shorten the development cycle of the electron gun. It has good promotion and application value.

The specific embodiments described above further describe the purpose, technical solutions and beneficial effects of the present invention in further detail. It should be understood that the above descriptions are only specific embodiments of the present invention, and are not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. an electron gun launch performance testing system, is characterized in that, comprises: The first vacuum chamber, the second vacuum chamber, the vacuum system, the electrode system and the electrical control system; The first vacuum chamber and the second vacuum chamber are used for placing the electron gun, wherein the first vacuum chamber is provided with an anode; the vacuum system is used for evacuating the first vacuum chamber and the second vacuum chamber; the electrode system is used to provide current and voltage to the electron gun; The electrical control system is used to control the action of the vacuum system and the electrode system, so as to test the gun emission performance of the electrons. 2. The electron gun emission performance testing system according to claim 1, wherein the vacuum system comprises an ion pump (1), a mechanical pump (59), a molecular pump (60) and a vacuum pipeline (3); The air inlet of the ion pump (1) is connected to the first vacuum chamber; The air inlet of the mechanical pump (59) is connected to the air outlet of the molecular pump (60), and the air inlet of the molecular pump (60) is connected to the second vacuum chamber; The air inlet of the molecular pump (60) is connected with the air inlet of the ion pump (1) through the vacuum pipeline (3). 3. The electron gun emission performance testing system according to claim 2, wherein the vacuum pipeline (3) comprises a first port, a second port, a third port and a fourth port; The air inlet of the ion pump (1) is connected to the first port, and the second port is connected to the first vacuum chamber; The air inlet of the molecular pump (60) is connected to the fourth port, and the third port is connected to the second vacuum chamber. 4. The electron gun emission performance testing system according to claim 1, wherein the electrode system comprises a first electrode (8), a second electrode (10) and a third electrode (22), and one end of the three electrodes is connected to The other end of the vacuum system is connected to the electrical control system. 5. The electron gun emission performance testing system according to claim 3, wherein the first port and the second port are on the same vertical line, and the third port and the fourth port are on the same vertical line on-line. 6. The electron gun emission performance testing system according to claim 3, wherein the vacuum system further comprises a first pneumatic high vacuum baffle valve (4), a second pneumatic high vacuum baffle valve (9), a third pneumatic high vacuum baffle valve (9), a third Pneumatic high vacuum flapper valve (23), fourth pneumatic high vacuum flapper valve (30), fifth pneumatic high vacuum flapper valve (35), three-way connecting pipe (36), blind flange (37), the sixth pneumatic high vacuum flapper valve (38), the seventh pneumatic high vacuum flapper valve (39), the vacuum connecting pipe (40) and the third bellows (41); The air inlet of the mechanical pump (59) communicates with the molecular pump (60) through the fifth pneumatic high vacuum baffle valve (35), the three-way connecting pipe (36), and the third bellows (41). air outlet connection; The air inlet of the mechanical pump (59) passes through the fifth pneumatic high vacuum baffle valve (35), the vacuum connecting pipe (40) and the sixth pneumatic high vacuum baffle valve (38), the seventh pneumatic high vacuum baffle valve (38), and the seventh pneumatic high vacuum baffle valve (38). The vacuum flapper valve (39) is connected; The blind flange (37) is arranged beside the fourth port. 7. The electron gun emission performance testing system according to claim 3, wherein a first plug valve (2) is provided between the air inlet of the ion pump (1) and the first port, so A second plug-in valve (7) is arranged between the second port and the first vacuum chamber; A fourth insert valve (31) is arranged between the air inlet of the molecular pump (60) and the fourth port, and a third insert valve is arranged between the third port and the second vacuum chamber valve (24). 8. The electron gun emission performance testing system according to claim 1, wherein the electron gun emission performance testing system further comprises a vacuum gauge (42), a first resistance gauge (34), a second resistance gauge (61) and ionization gauge(62); The first resistance gauge (34) is connected to the vacuum gauge (42) for measuring the vacuum degree of the air inlet of the mechanical pump (59); The second resistance gauge (61) is connected to the vacuum gauge (42) for measuring the low vacuum degree of the first vacuum chamber and the second vacuum chamber; The ionization gauge (62) is connected to the vacuum gauge (42) for measuring the high vacuum degree of the first vacuum chamber and the second vacuum chamber. 9 . The electron gun emission performance testing system according to claim 8 , wherein the starting condition of the ion pump is that the vacuum degree of the air inlet is better than 5×10 ⁻⁴ pa, and the starting condition of the molecular pump is the The vacuum degree of the air port is not less than 10Pa. 10. A method for testing electron gun launch performance based on the electron gun launch performance test system described in any one of claims 1-9, characterized in that, comprising: S1, close all flapper valves, and open the first pneumatic high vacuum flapper valve; S2, placing the electron gun in the first vacuum chamber or the second vacuum chamber, so that the electrode of the electron gun is connected to the electrode of the system; S3, start the mechanical pump, and open the second, third, and fourth pneumatic high-vacuum flapper valves. When the vacuum degree at the air inlet of the mechanical pump is better than the first preset value, start the molecular pump, and open the third valve connected to the molecular pump. Second, third, fourth plug valve; S4, when the vacuum degree of the air inlet of the molecular pump is better than the second preset value, open the first flapper valve, and start the ion pump; S5, heating the electron gun, and testing the emission current, conductivity coefficient and surface temperature of the electron gun.