Ultrahigh vacuum micro-leakage valve structure

Abstract

The invention discloses an ultrahigh vacuum micro-leakage valve structure which comprises a shell structure, a valve element plate and a differential importer, and the differential importer is connected with the shell structure through a flange used for being connected to an ultrahigh vacuum cavity. The bottom end of the valve core plate is connected with the differential importer, so that the differential importer drives the valve core plate to move up and down; the valve element plate is provided with a micropore array composed of multiple rows of micropores, so that the row number of the micropores, exposed out of the flange, of the micropore array is linearly changed in the moving process of the valve element plate. The method has general significance for realizing accurate control of the gas exposure amount under the high vacuum condition, and can be particularly applied to a gas molecular beam source which needs to accurately control the gas leakage amount, or an ion beam source which is based on gas ionization and requires the ion beam to have extremely high stability.

Description

Technical Field

[0001] The present invention relates to the technical field of ultra-high vacuum, and particularly to a structure of an ultra-high vacuum micro leak valve. Background Art

[0002] Currently, an ultra-high vacuum micro leak valve is usually used to introduce a certain amount of gas into an ultra-high vacuum chamber. The valve generally includes a movable piston, an optically smooth sapphire end face and a matching metal gasket. By adjusting the adjustment knob, the screw shaft and the lever mechanism control the up and down movement of the piston, and a controlled gap is formed between the metal gasket and the sapphire itself, and the gas flow through them can be adjusted accordingly. However, for this type of valve structure, in the high vacuum section, the metal gasket is under a certain pressure acting on the sapphire end face, and it will undergo a certain deformation due to the elastic modulus of the metal itself. Therefore, when the screw shaft drives the piston to move up and down, the actual displacement to generate a void should subtract the recovery amount of the elastic deformation of the metal itself. This reason results in that when fine-tuning the gas flow rate of this type of valve core, the gas leakage amount and the driving distance of the screw shaft are not linear in the high vacuum stage ( Figure 1 ). This makes it difficult to precisely and controllably adjust the gas leakage amount in the high vacuum section. In addition, the adjustment repeatability of the valve core depends on the unchanged elastic modulus of the metal sealing gasket. When exposed to high-temperature baking or corrosive gases, the material mechanical properties of the metal sealing ring are changed, which will also cause the adjustment accuracy of the micro leak valve to decrease, and even reduce its service life.

[0003] In view of this, the present invention is specifically proposed. Summary of the Invention

[0004] The purpose of the present invention is to overcome the above technical deficiencies and provide a structure of an ultra-high vacuum micro leak valve to achieve the purpose of linearly controlling gas leakage.

[0005] To achieve the above technical purpose, the present invention adopts the following technical solutions:

[0006] According to one aspect of the present invention, there is provided a structure of an ultra-high vacuum micro leak valve, including a housing structure, a valve core plate and a differential introducer. The differential introducer is connected to the housing structure through a flange for connecting to an ultra-high vacuum chamber; the bottom end of the valve core plate is connected to the differential introducer so that the differential introducer drives the valve core plate to move up and down; the valve core plate has a micropore array composed of multiple rows of micropores, so that the number of micropore rows of the micropore array exposed from the flange is linearly changed during the movement of the valve core plate.

[0007] Optionally, a sealing gasket is provided between the valve core plate and the flange so that the micropore array is blocked or opened row by row by the sealing gasket during the movement of the valve core plate.

[0008] Optionally, the gasket is a fluororubber gasket.

[0009] Optionally, four corners of the valve core plate are further provided with ball positioning beads for tightly pressing the valve core plate against the inner side of the housing structure.

[0010] Optionally, the micropores of the micropore array have a diameter of 10 μm.

[0011] Optionally, the differential introducer includes a vertically arranged driving mandrel, and the upper end of the driving mandrel is fixed to the valve core plate by screws.

[0012] Optionally, the edge of the valve core plate is configured with a concave space, and bearings for enabling the valve core plate to move up and down along the inner side of the flange are arranged in the concave space.

[0013] Optionally, the flange is a CF double-edge flange.

[0014] Optionally, the valve core plate includes a quartz micropore plate.

[0015] A structure of an ultra-high vacuum micro-leak valve provided by the present invention can realize micro gas exposure to a vacuum chamber and realize linear control of the introduced gas volume. This invention has general significance for realizing precise control of gas exposure amount under high vacuum conditions, and can be particularly applied to a gas molecular beam source that requires precise control of gas leakage amount, or an ion beam source based on gas ionization and requiring extremely high stability of ion beam current. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic diagram of the gas leakage amount and the driving distance of the threaded shaft in the prior art at the high vacuum stage;

[0017] Figure 2 is a schematic structural diagram of a structure of an ultra-high vacuum micro-leak valve provided by an embodiment of the present invention (with flange and flange-removed states);

[0018] Figure 3 is a schematic side-sectional structural diagram of a structure of an ultra-high vacuum micro-leak valve provided by an embodiment of the present invention;

[0019] Figure 4 is Figure 3 a schematic enlarged side-sectional structural diagram at the micropore array;

[0020] Figure 5 is a schematic structural diagram of a valve core plate of a structure of an ultra-high vacuum micro-leak valve provided by an embodiment of the present invention;

[0021] In the figure:

[0022] 1 - housing structure; 2 - CF double-edge flange; 3 - differential introducer; 4 - valve core plate; 5 - driving mandrel; 6 - fluororubber gasket; 7 - quartz microporous plate; 8 - micropore array; 9 - ball positioning bead; 10 - bearing. Detailed implementation mode

[0023] In order to enable those skilled in the art to better understand the solution of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0024] A structure of an ultra-high vacuum micro-leak valve provided by an embodiment of the present invention, in combination with Figure 2-5 , includes a housing structure 1, a valve core plate 4 and a differential introducer 3. The differential introducer 3 is connected to the housing structure 1 through a flange for connecting to an ultra-high vacuum chamber; in this embodiment, the flange is a CF double-edge flange 2. The bottom end of the valve core plate 4 is connected to the differential introducer 3 so that the differential introducer 3 drives the valve core plate 4 to move up and down; the valve core plate 4 has a micropore array 8 composed of multiple rows of micropores, so that the number of micropore rows exposed from the flange of the micropore array can be linearly changed during the movement of the valve core plate.

[0025] The differential introducer 3 is a device with a bellows seal that drives a linear motion inside the vacuum through a rotary motion outside the vacuum. On the front end of the driving mandrel 5 of the differential introducer 3, the driving mandrel 5 is fixed to the valve core plate 4 by screws. Therefore, the movement of the driving mandrel 5 of the differential introducer 3 can drive the valve core plate 4 to perform up and down movement.

[0026] As an example, the valve core plate 4 includes a quartz microporous plate 7. The upper end of the plate has a rectangular micropore array 8 of 100×100, and the diameter of the micropores is 10 μm. A gasket is provided between the valve core plate and the flange to isolate the two end chambers, so that the micropore array is blocked or opened row by row by the gasket during the movement of the valve core plate. In this embodiment, the gasket is a fluororubber gasket 6.

[0027] The valve core plate 4 can move up and down through the bearings 10 on the side. In this embodiment, the bearings 10 can be arranged in the concave space constructed at the edge of the valve core plate 4. Ball positioning beads 9 are also provided at the four corners of the valve core plate 4 to tightly press the valve core plate 4 against the inside of the housing structure 1. Under the mutual tight pressing and extrusion of the ball positioning beads 9 and the fluorine rubber gasket 6, gas can only be transmitted through the matrix microholes 8. By moving the valve core plate 4, the microhole array 8 will be blocked or opened row by row by the fluorine rubber gasket 6. When the valve core plate 4 is moved until the microhole array 8 is blocked by the fluorine rubber gasket 6 for N rows of microholes, the gas throughput is the leakage of (100 - N) × 100 microholes. Based on this principle, through the linear adjustment of the differential introducer 3, a linear change in the gas exposure amount can be achieved, and the adjustment graduation is 1% in this configuration. By increasing the density of the microhole array, a finer adjustment graduation can also be achieved. At this time, by using the differential introducer 3 to drive the valve core plate 4 to move up and down to block the conduction and cut-off of the microholes, the linear control of the gas leakage amount on both sides of the chamber can be realized. According to calculations, due to the extremely low conductance of the quartz microholes, when the inlet pressure is 1 atmospheric pressure and the pumping speed of the main chamber is 100 L / s, this micro-leak valve can accurately control the chamber vacuum to vary between 10-9 mbar and 10-7 mbar.

[0028] The above are only the preferred embodiments of the present application. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present application, several improvements and refinements can still be made, and these improvements and refinements should also be regarded as the protection scope of the present application.

Claims

1. A structure of an ultra-high vacuum micro leak valve, characterized in that, It includes a housing structure, a valve core plate, and a differential introducer. The differential introducer is connected to the housing structure through a flange for connecting to an ultra-high vacuum chamber. The bottom end of the valve core plate is connected to the differential introducer so that the differential introducer drives the valve core plate to move up and down. The valve core plate has a microporous array composed of multiple rows of micropores, so that the number of micropore rows of the microporous array exposed from the flange is linearly changed during the movement of the valve core plate.

2. The structure of the ultra-high vacuum micro-leak valve according to claim 1, wherein A gasket is provided between the valve core plate and the flange so that the microporous array is blocked or opened row by row by the gasket during the movement of the valve core plate.

3. The structure of the ultra-high vacuum micro-leak valve according to claim 2, characterized in that, The gasket is a fluororubber gasket.

4. The structure of the ultra-high vacuum micro-leak valve according to claim 2, wherein, Ball positioning beads are also provided at the four corners of the valve core plate for pressing the valve core plate tightly against the inner side of the housing structure.

5. The structure of the ultra-high vacuum micro-leak valve according to claim 1, characterized in that, The micropores of the microporous array have a diameter of 10 μm.

6. The structure of the ultra-high vacuum micro-leak valve according to claim 1, characterized in that, The differential introducer includes a vertically arranged driving mandrel, and the upper end of the driving mandrel is fixed to the valve core plate by screws.

7. The structure of the ultra-high vacuum micro-leak valve according to claim 1, characterized in that, A concave space is formed at the edge of the valve core plate, and bearings are provided in the concave space to enable the valve core plate to move up and down along the inner side of the flange.

8. The structure of the ultra-high vacuum micro-leak valve according to any one of claims 1-7, characterized in that, The flange is a CF double-edge flange.

9. The ultra-high vacuum micro-leak valve structure according to any one of claims 1-7, characterized in that, The valve core plate includes a quartz microporous plate.

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