Cathode Anti-evaporation device and electronic gun

Abstract

A cathode anti-evaporation device and an electronic gun. The cathode anti-evaporation device comprises a first vacuum chamber (10), a second vacuum chamber (20), molecular pumps and mechanical pumps, wherein a cathode is arranged inside the first vacuum chamber (10); the second vacuum chamber (20) is in communication with the first vacuum chamber (10) to form a differential vacuum system, the vacuum degree of the first vacuum chamber (10) can increase as the vacuum degree of the second vacuum chamber (20) increases, and the vacuum degree of the first vacuum chamber (10) is greater than the vacuum degree of the second vacuum chamber (20); the molecular pumps comprise a first molecular pump (31) and a second molecular pump (32), the first molecular pump (31) being configured to be in selective communication with the first vacuum chamber (10), and the second molecular pump (32) being configured to be in selective communication with the second vacuum chamber (20); and the mechanical pumps comprise a first mechanical pump (41) and a second mechanical pump (42), the first molecular pump (31) being cascaded with the first mechanical pump (41), and the second molecular pump (32) being cascaded with the second mechanical pump (42).

Description

Cathode anti-evaporation device and electron gun

[0001] This application claims priority to the Chinese patent application No. 202410647955.X filed on May 23, 2024 with the Chinese Patent Office, the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the technical field of electron guns, for example to a cathode anti-evaporation device and electron gun. BACKGROUND

[0003] In an electron gun, tungsten, lanthanum hexaboride (LaB_6) or tantalum and other materials are generally used as cathodes. As an emitter, the cathode generates a large number of hot electrons on the surface after heating to work. Due to the high temperature of the cathode during the operation of the electron gun, long-term operation at high temperature will cause the cathode to evaporate and erode, resulting in poor electron beam quality.

[0004] In related technologies, a flow channel is usually provided on the cathode, and then the flow of liquid or gas is used to exchange heat with the cathode. In this method, the material and manufacturing costs are large, and the heat exchange efficiency is lost in the flow channel, resulting in poor heat exchange effect.

[0005] SUMMARY

[0006] The present application provides a cathode anti-evaporation device and electron gun, which can solve the problems of using the flow of liquid or gas to exchange heat with the cathode in related technologies, large material and manufacturing costs, and poor heat exchange effect, reduce the cost of cathode anti-evaporation, improve the efficiency of cathode anti-evaporation, and improve the service life of the cathode.

[0007] An embodiment of the present application provides a cathode anti-evaporation device, comprising:

[0008] A first vacuum chamber, a second vacuum chamber, a molecular pump and a mechanical pump, the cathode is arranged in the first vacuum chamber; the second vacuum chamber is in communication with the first vacuum chamber and forms a differential vacuum system, the vacuum degree of the first vacuum chamber can be increased with the increase of the vacuum degree of the second vacuum chamber, and the vacuum degree of the first vacuum chamber is greater than that of the second vacuum chamber; the molecular pump comprises a first molecular pump and a second molecular pump, the first molecular pump is arranged to be selectively in communication with the first vacuum chamber, and the second molecular pump is arranged to be selectively in communication with the second vacuum chamber; the mechanical pump comprises a first mechanical pump and a second mechanical pump, the first molecular pump and the first mechanical pump are cascaded, and the second molecular pump and the second mechanical pump are cascaded.

[0009] In an embodiment, the first mechanical pump is arranged to be selectively in communication with the first vacuum chamber, and the second mechanical pump is arranged to be selectively in communication with the second vacuum chamber.

[0010] In an embodiment, the cathode anti-evaporation device further comprises a roughing valve, the roughing valve is arranged between the second mechanical pump and the second vacuum chamber, and the roughing valve is configured to selectively communicate or not communicate the second mechanical pump and the second vacuum chamber.

[0011] In an embodiment, the front-stage valve further comprises a second front-stage valve, the second front-stage valve is arranged between the second mechanical pump and the second molecular pump, and the second front-stage valve is configured to selectively communicate or not communicate the second molecular pump and the second mechanical pump.

[0012] In an embodiment, the cathode anti-evaporation device further comprises a roughing valve, the roughing valve is arranged between the second mechanical pump and the second vacuum chamber, and the roughing valve is configured to selectively communicate or not communicate the second mechanical pump and the second vacuum chamber.

[0013] In an embodiment, the cathode anti-evaporation device further comprises a high vacuum valve, the high vacuum valve is arranged between the second molecular pump and the second vacuum chamber, and the high vacuum valve is configured to selectively communicate or not communicate the second molecular pump and the second vacuum chamber.

[0014] In an embodiment, the cathode anti-evaporation device further comprises an exhaust valve, the exhaust valve comprises a first exhaust valve, the first exhaust valve is arranged on the first molecular pump, and the first exhaust valve is configured to selectively communicate the first molecular pump with the outside to communicate the first vacuum chamber with the outside.

[0015] In an embodiment, the exhaust valve further comprises a second exhaust valve, the second exhaust valve is arranged on the second vacuum chamber, and the second exhaust valve is configured to selectively communicate the second vacuum chamber with the outside.

[0016] In an embodiment, the cathode anti-evaporation device further comprises a programmable logic controller, the logic controller is configured to control the first molecular pump and the second molecular pump to work or not work.

[0017] An embodiment of the present application further provides an electron gun, comprising the cathode anti-evaporation device. BRIEF DESCRIPTION OF DRAWINGS

[0018] FIG. 1 is a schematic view of a cathode anti-evaporation device provided by an embodiment of the present application.

[0019] In the figure: 100, cathode; 10, first vacuum chamber; 20, second vacuum chamber; 31, first molecular pump; 32, second molecular pump; 41, first mechanical pump; 42, second mechanical pump; 51, first forevacuum valve; 52, second forevacuum valve; 60, roughing valve; 70, high vacuum valve; 81, first exhaust valve; 82, second exhaust valve. DETAILED DESCRIPTION

[0020] In the description of the present application, unless otherwise explicitly specified and limited, the terms "connected", "connected", "fixed" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0021] In the present application, unless otherwise explicitly specified and limited, the first feature "on" or "under" the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the first feature "on", "above" and "above" the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "under", "below" and "below" the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0022] In the description of the present embodiment, the terms "up", "down", "right", and other orientation or position relationships are based on the orientation or position relationship shown in the drawings, and are only for the convenience of description and simplification of operation, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0023] In the related art, a flow channel is usually provided on the cathode, and the flow of liquid or gas is used to exchange heat with the cathode; in this method, the material and manufacturing cost is large, and the heat exchange efficiency is lost in the flow channel, and the heat exchange effect is poor.

[0024] To solve the above problems, the embodiment provides an electron gun, which comprises a cathode anti-evaporation device. Referring to FIG. 1, the cathode anti-evaporation device comprises a first vacuum chamber 10, a second vacuum chamber 20, a molecular pump and a mechanical pump, and a cathode 100 is arranged in the first vacuum chamber 10; the second vacuum chamber 20 is in communication with the first vacuum chamber 10 and forms a differential vacuum system, the vacuum degree of the first vacuum chamber 10 can be increased along with the increase of the vacuum degree of the second vacuum chamber 20, and the vacuum degree of the first vacuum chamber 10 is greater than that of the second vacuum chamber 20; the molecular pump comprises a first molecular pump 31 and a second molecular pump 32, the first molecular pump 31 can selectively communicate with the first vacuum chamber 10, and the second molecular pump 32 can selectively communicate with the second vacuum chamber 20; the mechanical pump comprises a first mechanical pump 41 and a second mechanical pump 42, the first molecular pump 31 is connected in cascade with the first mechanical pump 41, and the second molecular pump 32 is connected in cascade with the second mechanical pump 42. The second vacuum chamber 20 reaches a medium vacuum degree through the second molecular pump 32, so that the first vacuum chamber 10 reaches a high vacuum state through the first molecular pump 31, thereby avoiding evaporation of the cathode 100; and the differential vacuum system avoids using a high vacuum device, reduces the cost of anti-evaporation of the cathode 100, improves the efficiency of anti-evaporation of the cathode 100, prolongs the service life of the cathode 100, and thus improves the stability of the beam current density of the electron gun.

[0025] In an embodiment, in order to gradually increase the vacuum degrees in the first vacuum chamber 10 and the second vacuum chamber 20, the first mechanical pump 41 can selectively communicate with the first vacuum chamber 10, and the second mechanical pump 42 can selectively communicate with the second vacuum chamber 20. The first mechanical pump 41 and the second mechanical pump 42 can make the first vacuum chamber 10 and the second vacuum chamber 20 reach a low vacuum state from a rough vacuum state, about 10 Pa.

[0026] In an embodiment, the cathode anti-evaporation device further comprises a front-stage valve, the front-stage valve comprises a first front-stage valve 51 and a second front-stage valve 52, the first front-stage valve 51 is arranged between the first mechanical pump 41 and the first vacuum chamber 10, and the first front-stage valve 51 can selectively make the first mechanical pump 41 and the first vacuum chamber 10 communicate or not communicate. The second front-stage valve 52 is arranged between the second mechanical pump 42 and the second molecular pump 32, and the second front-stage valve 52 can selectively make the second molecular pump 32 and the second mechanical pump 42 communicate or not communicate.

[0027] In order to further increase the vacuum degree of the second vacuum chamber 20, the cathode anti-evaporation device further comprises a rough vacuum valve 60, the rough vacuum valve 60 is arranged between the second mechanical pump 42 and the second vacuum chamber 20, and the rough vacuum valve 60 can selectively make the second mechanical pump 42 and the second vacuum chamber 20 communicate or not communicate.

[0028] When the second mechanical pump 42 and the second molecular pump 32 are independent, the second mechanical pump 42 is arranged to make the second vacuum chamber 20 reach a low vacuum state, and the second molecular pump 32 is arranged to make the second vacuum chamber 20 reach a medium vacuum state; when the second mechanical pump 42 and the second molecular pump 32 are connected in parallel, the second mechanical pump 42 and the second molecular pump 32 jointly act to make the second vacuum chamber 20 reach a high vacuum state, about 10-1Pa-10-6Pa; when the second vacuum chamber 20 reaches the high vacuum state, due to the differential vacuum system, the first vacuum chamber 10 can reach a higher vacuum state through the first molecular pump 31, so that the cathode 100 is in a high vacuum environment, avoiding evaporation.

[0029] In an embodiment, when the second vacuum chamber 20 is 10-3Pa, the first vacuum chamber 10 can reach 10-5Pa-10-6Pa.

[0030] In an embodiment, the cathode evaporation-proof device further comprises a high vacuum valve 70, which is arranged between the second molecular pump 32 and the second vacuum chamber 20, and the high vacuum valve 70 can selectively make the second molecular pump 32 and the second vacuum chamber 20 communicate or not communicate.

[0031] In an embodiment, when the second vacuum chamber 20 needs to reach a low vacuum state, the second front-stage valve 52 and the high vacuum valve 70 are closed, and the rough vacuum valve 60 is opened; when the second vacuum chamber 20 needs to reach a medium vacuum state, the second front-stage valve 52 and the rough vacuum valve 60 are closed, and the high vacuum valve 70 is opened; when the second vacuum chamber 20 needs to reach a high vacuum state, one of the high vacuum valve 70 or the rough vacuum valve 60 is closed, and the other and the second front-stage valve 52 are opened.

[0032] In an embodiment, the cathode evaporation-proof device further comprises an exhaust valve, which comprises a first exhaust valve 81, the first exhaust valve 81 is arranged on the first molecular pump 31, and the first exhaust valve 81 can selectively make the first molecular pump 31 communicate with the outside, so that the first vacuum chamber 10 communicates with the outside. The first exhaust valve 81 is arranged to release the vacuum state of the first vacuum chamber 10.

[0033] In an embodiment, the exhaust valve further comprises a second exhaust valve 82, the second exhaust valve 82 is arranged on the second vacuum chamber 20, and the second exhaust valve 82 can selectively make the second vacuum chamber 20 communicate with the outside. The second exhaust valve 82 is arranged to release the vacuum state of the second vacuum chamber 20.

[0034] In one embodiment, the cathode evaporation resistant device further comprises a programmable logic controller configured to control the first and second molecular pumps 31, 32 to be on or off. In one embodiment, the logic controller is configured to control the opening and closing of the backing valve, roughing valve 60, high vacuum valve 70 and exhaust valve to avoid damage to the device from human error (miscontrol of the valves) during the process of increasing the vacuum in the first and second vacuum chambers 10, 20.

Claims

1. A cathode evaporation resistant apparatus, comprising: a first vacuum chamber (10) in which a cathode (100) is disposed; a second vacuum chamber (20) in communication with the first vacuum chamber (10) and forming a differential vacuum system, the vacuum level of the first vacuum chamber (10) being capable of being increased as the vacuum level of the second vacuum chamber (20) is increased, and the vacuum level of the first vacuum chamber (10) being greater than the vacuum level of the second vacuum chamber (20); molecular pumps, including a first molecular pump (31) disposed in selective communication with the first vacuum chamber (10) and a second molecular pump (32) disposed in selective communication with the second vacuum chamber (20); and mechanical pumps, including a first mechanical pump (41) in cascade with the first molecular pump (31) and a second mechanical pump (42) in cascade with the second molecular pump (32).

2. The cathode anti-evaporation device according to claim 1, wherein The first mechanical pump (41) is disposed in selective communication with the first vacuum chamber (10) and the second mechanical pump (42) is disposed in selective communication with the second vacuum chamber (20).

3. The cathode evaporation resistant apparatus of claim 2, further comprising a backing valve, the backing valve including a first backing valve (51) disposed between the first mechanical pump (41) and the first vacuum chamber (10), the first backing valve (51) being disposed in selective communication or non-communication between the first mechanical pump (41) and the first vacuum chamber (10).

4. The cathode anti-evaporation device according to claim 3, wherein The backing valve further includes a second backing valve (52) disposed between the second mechanical pump (42) and the second molecular pump (32), the second backing valve (52) being disposed in selective communication or non-communication between the second molecular pump (32) and the second mechanical pump (42).

5. The cathode evaporation resistant apparatus of claim 2, further comprising a roughing valve (60) disposed between the second mechanical pump (42) and the second vacuum chamber (20), the roughing valve (60) being disposed in selective communication or non-communication between the second mechanical pump (42) and the second vacuum chamber (20).

6. The cathode evaporation resistant apparatus of any one of claims 1-5, further comprising a high vacuum valve (70) disposed between the second molecular pump (32) and the second vacuum chamber (20), the high vacuum valve (70) being disposed in selective communication or non-communication between the second molecular pump (32) and the second vacuum chamber (20).

7. The cathode anti-evaporation device according to any of claims 1-5, further comprising an exhaust valve, said exhaust valve comprising a first exhaust valve (81) arranged on said first molecular pump (31), said first exhaust valve (81) being arranged to selectively communicate said first molecular pump (31) with the outside, so as to communicate said first vacuum chamber (10) with the outside.

8. The cathode anti-evaporation device according to claim 7, wherein Said exhaust valve further comprises a second exhaust valve (82) arranged on said second vacuum chamber (20), said second exhaust valve (82) being arranged to selectively communicate said second vacuum chamber (20) with the outside.

9. The cathode anti-evaporation device according to any of claims 1-5, further comprising a programmable logic controller arranged to control said first molecular pump (31) and said second molecular pump (32) to work or not to work.

10. Electron gun comprising a cathode anti-evaporation device according to any of claims 1-9.

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