Preparation method of distributed micro-focus X-ray beam

Abstract

The invention relates to a preparation method of a distributed micro-focus X-ray beam, belongs to the technical field of static CT (Computed Tomography), and solves the problems of poor electron beam consistency and difficulty in control of an existing distributed micro-focus X-ray source. The method comprises the following steps: introducing inert gas into a gas discharge chamber, and applying preset power supply voltage to an electrode of the gas discharge chamber, so that the inert gas discharges to generate plasma; a lead-out plate with a plurality of lead-out holes is arranged at the outlet of the gas discharge chamber, and preset lead-out voltage is applied to the lead-out plate, so that the plasma is led out from the lead-out holes to form a plurality of electron beams; a focusing electrode plate and a target are sequentially arranged below the leading-out plate, a preset focusing voltage with the potential lower than the leading-out voltage is applied to the focusing electrode plate, all the focused electron beams bombard the target, and therefore the distributed micro-focus X-ray beam is generated. The prepared distributed micro-focus X-ray beam base is high in consistency, convenient to control, good in stability and long in service life.

Description

Technical Field

[0001] The invention relates to the technical field of static CT, and in particular to a method for preparing a distributed micro-focus X-ray beam. Background Art

[0002] Static CT uses a high spatial density distributed X-ray source to replace the mechanical rotating structure of spiral CT. It can scan the object to be inspected from all angles to obtain its imaging data. It has the advantages of fast scanning speed and high detection efficiency. It also overcomes the shortcomings of traditional CT machines such as large size and high cost. Static CT technology has great application prospects in both industrial non-destructive testing and medical CT imaging. Therefore, many researchers have invested a lot of energy in the study of the key core component of static CT - distributed X-ray source.

[0003] At present, there are two ways to obtain distributed X-ray sources: one is a micro-focus X-ray source based on electron beam deflection scanning array; the second is an X-ray source using a distributed electron emission source. The distributed X-ray sources obtained by these two ways have achieved certain results in static CT applications, but there are still some unresolved problems. Specifically, the micro-focus X-ray source based on electron beam deflection scanning array has problems such as complex magnetic deflection system, low light source intensity, poor focus repeatability, projection data truncation and redundancy, and high price. There are mainly two ways of existing distributed electron emission source X-ray sources. One is a distributed electron emission source X-ray source based on carbon nanotube field emission cathode. This type of X-ray source has problems such as poor consistency of electron beam intensity, short life and poor stability. The other is a distributed electron emission source X-ray source based on thermal emission cathode. This type of X-ray source has problems such as high output power, difficult anode thermal management and high voltage ignition. Summary of the invention

[0004] In view of the above analysis, an embodiment of the present invention aims to provide a method for preparing a distributed micro-focus X-ray beam, so as to solve the problem that the electron beam of the existing distributed micro-focus ray source has poor consistency and is difficult to control.

[0005] In one aspect, an embodiment of the present invention provides a method for preparing a distributed micro-focus X-ray beam, the method comprising:

[0006] Introducing an inert gas into a gas discharge chamber, and applying a preset power supply voltage to electrodes of the gas discharge chamber, so that the inert gas discharges to generate plasma;

[0007] An extraction plate is arranged at the outlet of the gas discharge chamber, and a plurality of extraction holes are arranged on the extraction plate. By applying a preset extraction voltage on the extraction plate, the plasma is extracted from the extraction holes to form a plurality of electron beams;

[0008] A focusing electrode plate is arranged below the extraction plate, and a focusing voltage with a preset potential lower than the extraction voltage is applied to the focusing electrode plate, so that each electron beam is focused through the focusing electrode plate;

[0009] A target is arranged below the focusing electrode plate so that all focused electron beams bombard the target, thereby generating a distributed micro-focus X-ray beam.

[0010] Based on the further improvement of the above method, the method further includes:

[0011] The intensity of the generated distributed micro-focus X-ray beam is controlled by controlling the flow rate of the inert gas introduced into the gas discharge chamber.

[0012] Based on the further improvement of the above method, the method further includes:

[0013] The intensity of the generated distributed micro-focus X-ray beam is controlled by controlling a preset extraction voltage applied to the extraction plate.

[0014] Based on further improvement of the above method, the extraction voltage has a value range of -1000V to -5V.

[0015] Based on the further improvement of the above method, the method comprises:

[0016] The focus size of the generated distributed micro-focus X-ray beam is controlled by adjusting the number of the focusing electrode plates and / or the focusing voltage applied to the focusing electrode plates.

[0017] Based on the further improvement of the above method, the number of the focusing electrode plate is one, and the value range of the focusing voltage applied to the focusing electrode plate is -2000-0V.

[0018] Based on the further improvement of the above method, the number of the focusing electrode plates is set to three, namely a first focusing electrode plate, a second focusing electrode plate and a third focusing electrode plate; the first focusing electrode plate, the second focusing electrode plate and the third focusing electrode plate are sequentially arranged below the lead-out plate, and the first focusing electrode plate, the second focusing electrode plate and the third focusing electrode plate are arranged in parallel with equal spacing;

[0019] The focusing voltage applied to the first focusing electrode plate has a value range of -1800-0V;

[0020] The focusing voltage applied to the second focusing electrode plate has a value range of -2000-0V;

[0021] The focus voltage applied on the third focus electrode plate has a value range of -1200-0V.

[0022] Based on the further improvement of the above method, the method further includes:

[0023] The position of each X-ray of the distributed micro-focus X-ray beam is controlled by adjusting the position of each of the lead-out holes on the lead-out plate.

[0024] Based on the further improvement of the above method, the method further includes:

[0025] The spot shape and size of the distributed micro-focus X-ray beam are controlled respectively by adjusting the shape and size of the lead-out hole.

[0026] Based on the further improvement of the above method, the method comprises:

[0027] Selecting a power source type and a discharge mode of the gas discharge chamber, and preparing the gas discharge chamber according to the power source type and the discharge mode;

[0028] The power supply types include: DC power supply, AC power supply and high frequency power supply;

[0029] The discharge modes include glow discharge, radio frequency discharge and microwave discharge.

[0030] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0031] 1. In the present invention, plasma is generated in a gas discharge chamber, and a preset extraction voltage is applied to the extraction holes, so that multiple electron beams can be simultaneously extracted from the multiple extraction holes at different positions. The multiple focused electron beams bombard the target, thereby generating a distributed micro-focus X-ray beam. The consistency of each electron beam is high, and thus a distributed micro-focus X-ray beam with high consistency can be obtained. The distributed micro-focus X-ray beam of the present invention is obtained based on a plasma cathode, has a long service life, is not limited by thermal management, and has the advantages of good stability, good focus repeatability, and high light source intensity.

[0032] 2. In the present invention, by controlling the flow rate of the inert gas introduced into the gas discharge chamber, or by controlling the preset extraction voltage applied to the extraction plate, the intensity of the distributed microfocus X-ray beam can be controlled in a large range, and the controllability is strong.

[0033] 3. In the present invention, a plasma cathode is used, and by setting the position, shape, size and number of lead-out holes on the lead-out plate, the position, spacing, shape and number of rays of the microfocus X-ray beam can be controlled, and the controllability is high.

[0034] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0036] Figure 1 A flow chart of a method for preparing a distributed micro-focus X-ray beam according to an embodiment of the present invention;

[0037] Figure 2 A schematic diagram of the structure of an X-ray source according to an embodiment of the present invention;

[0038] Figure 3 A schematic structural diagram of a cavity wall of a gas discharge chamber according to an embodiment of the present invention;

[0039] Figure 4 It is a structural schematic diagram of the lead-out board of the first embodiment of the present invention;

[0040] Figure 5 It is a structural schematic diagram of the lead-out board of the second embodiment of the present invention;

[0041] Figure 6 This is a schematic diagram of the structure of the lead-out board of the third embodiment of the utility model;

[0042] Figure 7 It is a schematic structural diagram of the lead-out plate of the fourth embodiment of the utility model.

[0043] Reference numerals:

[0044] 1-gas discharge chamber; 1a-gas delivery hole;

[0045] 2-lead plate; 2a, 2b, 2c, 2d-lead holes;

[0046] 3-focusing electrode plate; 4-target; 5-plasma;

[0047] 6-Electron beam; 7-Microfocus X-ray beam. DETAILED DESCRIPTION

[0048] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0049] A specific embodiment of the present invention discloses a method for preparing a distributed micro-focus X-ray beam, such as Figure 1 The method comprises:

[0050] Inert gas is introduced into the gas discharge chamber 1, and a preset power supply voltage is applied to the electrodes of the gas discharge chamber 1, so that the inert gas discharges to generate plasma 5;

[0051] An extraction plate 2 is provided at the outlet of the gas discharge chamber 1, and a plurality of extraction holes are provided on the extraction plate 2. By applying a preset extraction voltage on the extraction plate 2, the plasma 5 is extracted from the extraction holes to form a plurality of electron beams 6;

[0052] A focusing electrode plate 3 is arranged below the extraction plate 2, and a focusing voltage with a preset potential lower than the extraction voltage is applied to the focusing electrode plate 3, so that each electron beam 6 is focused through the focusing electrode plate 3;

[0053] A target 4 is arranged below the focusing electrode plate so that all focused electron beams 6 bombard the target 4 , thereby generating a distributed micro-focus X-ray beam 7 .

[0054] During implementation, the gas discharge chamber 1 works on the principle of gas discharge. When the voltage applied to the two electrode ends of the gas discharge chamber 1 reaches the point where the gas in the gas discharge chamber 1 breaks down, the gas discharge chamber 1 starts to discharge, and the gas generates plasma 5 during the discharge process. The generated plasma 5 is led out by the lead-out plate 2 to form an electron beam 6. The focusing electrode plate 3 affects the electron beam 6 by generating an electric field, so that the electron beam 6 is focused. After the electron beam 6 is focused, it bombards the target 4, which can improve the efficiency and effect of the interaction between the electron beam 6 and the target 4 material. The electron beam 6 interacts with the atomic nuclei of the target 4 material, thereby generating a micro-focus X-ray beam 7.

[0055] In the distributed X-ray source of the prior art, multiple independent carbon nanotube field emission cathodes or thermal emission cathodes are configured at different positions in an X-ray tube to generate X-rays. These cathodes can be controlled individually, but there are certain technical challenges in achieving precise synchronous control between them. In addition, since the cathodes may have differences in structure or material, these differences may cause the electron beam 6 characteristics they generate to be inconsistent, which in turn affects the consistency and uniformity of the final microfocus X-ray beam 7. This inconsistency may have an adverse effect on the quality of X-ray imaging.

[0056] Compared with the prior art, in the embodiment of the present invention, a plasma 5 is generated by a gas discharge chamber 1, and a preset extraction voltage is applied to the extraction hole, so that multiple electron beams 6 can be simultaneously extracted from the multiple extraction holes at different positions, and the multiple focused electron beams 6 bombard the target 4, thereby generating a distributed micro-focus X-ray beam 7, and the consistency of each electron beam 6 is high, thereby obtaining a distributed micro-focus X-ray beam 7 with high consistency, and the distributed micro-focus X-ray beam 7 of the present invention is obtained based on the plasma 5 cathode, has a long service life, is not limited by thermal management, and has the advantages of good stability, good focus repeatability, and high light source intensity.

[0057] Specifically, the gas in the gas discharge chamber 1 is argon or neon. Argon or neon is a commonly used inert gas, which can generate a high-energy micro-focus X-ray beam 7 during discharge. In addition, the gas in the gas discharge chamber 1 can be other inert gases such as krypton.

[0058] Specifically, the target 4 is a reflective target 4 or a transmissive target 4 , preferably a reflective target 4 .

[0059] In one embodiment, the method further comprises: controlling the intensity of the generated distributed micro-focus X-ray beam 7 by controlling the flow rate of the inert gas introduced into the gas discharge chamber 1 .

[0060] The intensity of the electron beam 6 can be changed by adjusting the flow rate of the introduced inert gas, thereby changing the intensity of the generated distributed micro-focus X-ray beam 7.

[0061] During implementation, the inert gas is introduced into the gas discharge chamber 1 at a uniform flow rate / flow velocity to ensure the stability of the distributed micro-focus X-ray beam 7 .

[0062] Specifically, the cavity wall of the gas discharge chamber 1 is provided with a plurality of evenly distributed gas delivery holes 1a, such as Figure 3 as shown in .

[0063] Specifically, the method further includes: controlling the intensity of the generated distributed micro-focus X-ray beam 7 by applying a preset extraction voltage on the extraction plate 2 .

[0064] The extraction voltage has a value range of -1000V to -5V.

[0065] In the present invention, by controlling the flow rate of the inert gas introduced into the gas discharge chamber 1, or by controlling the preset extraction voltage applied to the extraction plate 2, the intensity of the distributed microfocus X-ray beam 7 can be controlled within a larger range, and the controllability is strong.

[0066] In one embodiment, the method comprises:

[0067] The focus size of the generated distributed micro-focus X-ray beam 7 is controlled by adjusting the number of the focusing electrode plates 3 and / or the focusing voltage applied to the focusing electrode plates 3 .

[0068] In the embodiment of the present invention, the electrostatic focusing of the electron beam 6 can adopt monopole focusing or multipole focusing, preferably multi-stage focusing, wherein a better focusing effect can be obtained by multi-stage focusing, making the focus smaller. When multiple focusing electrode plates 3 are provided, the voltage adjustment of each focusing electrode plate 3 can affect the size of the focus. In the embodiment of the present invention, the voltage of each focusing electrode is allowed to be adjusted independently, thereby achieving fine control.

[0069] Specifically, the number of the focusing electrode plate 3 is one, and the value range of the focusing voltage applied to the focusing electrode plate 3 is -2000-0V.

[0070] Specifically, the number of the focusing electrode plates 3 is set to three, namely, a first focusing electrode plate, a second focusing electrode plate and a third focusing electrode plate; the first focusing electrode plate, the second focusing electrode plate and the third focusing electrode plate are sequentially arranged below the lead-out plate 2, and the first focusing electrode plate, the second focusing electrode plate and the third focusing electrode plate are arranged in parallel with equal spacing;

[0071] The focusing voltage applied to the first focusing electrode plate has a value range of -1800-0V;

[0072] The focusing voltage applied to the second focusing electrode plate has a value range of -2000-0V;

[0073] The focus voltage applied on the third focus electrode plate has a value range of -1200-0V.

[0074] During implementation, focusing voltages of different potentials are applied to the three focusing electrode plates 3, wherein the potential of the third focusing electrode plate is slightly lower than that of the lead-out plate 2, and the potentials of the first focusing electrode plate and the second focusing electrode plate between the lead-out plate 2 and the third focusing electrode plate are several hundred volts lower than that of the lead-out electrode.

[0075] In one embodiment, the method further comprises: controlling the position of each X-ray of the distributed micro-focus X-ray beam 7 by adjusting the position of each of the lead-out holes on the lead-out plate 2 .

[0076] Specifically, the method further includes: controlling the spot shape and size of the distributed micro-focus X-ray beam 7 by adjusting the shape and size of the lead-out hole.

[0077] In the embodiment of the present invention, a plasma cathode is used, and by setting the position, shape, size and number of the lead-out holes on the lead-out plate 2, the position, spacing, shape and number of rays of the microfocus X-ray beam 7 can be controlled, and the controllability is high.

[0078] Specifically, the lead-out hole is in a circular, triangular, rectangular or linear shape.

[0079] Specifically, the plurality of lead-out holes are arranged in an array on the lead-out plate 2 , such as a circular array, a rectangular array, a triangular array, a linear array, or a plurality of linear arrays (orthogonal array).

[0080] Specifically, the distance between two adjacent lead-out holes is 0.5 mm to 10 mm.

[0081] Specifically, the inner diameter of the lead-out hole is 100 μm to 1000 μm.

[0082] During implementation, the focal size of the micro-focus X-ray beam 7 prepared by the method of the embodiment of the present invention is 5 μm to 100 μm, preferably 5 μm. The smaller the focal size of the micro-focus X-ray beam 7, the more concentrated the projection of the X-rays is, which is conducive to improving the imaging quality and obtaining better detail recognition capabilities.

[0083] In one embodiment, the method comprises:

[0084] Selecting a power source type and a discharge mode of the gas discharge chamber 1, and designing the gas discharge chamber 1 according to the power source type and the discharge mode;

[0085] The power supply types include: DC power supply, AC power supply and high frequency power supply;

[0086] The discharge modes include glow discharge, radio frequency discharge and microwave discharge.

[0087] When designing the gas discharge chamber 1, it is crucial to select the power type and discharge mode. Among them, the three power modes of DC discharge, AC discharge and high frequency discharge (including radio frequency discharge and microwave discharge) can be combined with the three discharge forms of glow discharge, radio frequency discharge and microwave discharge to meet different application requirements. Each combination has its specific application and advantages. When designing the discharge chamber, it is necessary to select the appropriate discharge mode and parameters according to the specific application requirements.

[0088] In the embodiment of the present invention, the power supply type of the gas discharge chamber 1 is preferably a direct current power supply, and the discharge mode is preferably microwave discharge. The direct current power supply provides a stable voltage source, while the microwave discharge allows high-energy plasma 5 to be generated in the gas, thereby facilitating the generation of a stable, high-intensity distributed micro-focus X-ray beam 7.

[0089] In addition, the material of the lead-out plate 2 is designed according to the discharge mode of the gas discharge chamber 1. Different discharge modes have different requirements on the tolerance, conductivity, thermal stability and chemical stability of the lead-out plate 2 material. The lead-out electrode material generally includes metal materials such as molybdenum, tungsten or other high-performance alloys.

[0090] Specifically, the cross section of the gas discharge chamber 1 is circular or rectangular. The shape of the gas discharge chamber 1 is one of the key factors for achieving efficient, stable and uniform discharge. Setting the cross section of the gas discharge chamber 1 to a circular or rectangular shape is conducive to ensuring the discharge efficiency and discharge stability of the plasma 5.

[0091] Embodiment 1

[0092] The X-ray source of this embodiment includes a discharge chamber, an extraction plate 2, a focusing electrode plate 3 and a target 4. The cross section of the gas discharge chamber 1 is rectangular. Figure 4 As shown, the lead plate 2 has lead holes 2a arranged in a linear array, the lead holes 2a are circular in shape, with a diameter of 100 μm, the number of lead holes is set according to actual needs, and the hole spacing is 0.5 mm. A focusing electrode plate 3 is arranged below the lead plate 2, and the number is one.

[0093] Preparation of gas discharge chamber: Using a DC power supply and glow discharge method, design the anode layer gas discharge chamber 1.

[0094] An extraction voltage of -50V is applied to the extraction plate 2 to extract the array electron beam 6. A focusing voltage of -300V is applied to the focusing electrode plate 3 to perform focusing.

[0095] Embodiment 2

[0096] The X-ray source of this embodiment includes a discharge chamber, an extraction plate 2, a focusing electrode plate 3 and a target 4. The cross section of the gas discharge chamber 1 is circular. Figure 5 As shown, the lead plate 2 has lead holes 2b arranged in a circular array, the lead holes 2b are circular in shape, with a diameter of 200 μm, the number of lead holes is set according to actual needs, and the hole spacing is 1 mm. The focusing electrode plate 3 is set below the lead plate 2, and the number is three.

[0097] Preparation of gas discharge chamber: Using AC power supply and glow discharge method, design the anode layer gas discharge chamber 1.

[0098] A -100V extraction voltage is applied to the extraction plate 2 to extract the array electron beam 6. A -500V focusing voltage is applied to the first focusing electrode plate 3, a -300V focusing voltage is applied to the second focusing electrode plate 3, and a -105V focusing voltage is applied to the third focusing electrode plate 3 for focusing.

[0099] Embodiment 3

[0100] The X-ray source of this embodiment includes a discharge chamber, an extraction plate 2, a group of focusing electrode plates 3 and a target 4. The cross section of the gas discharge chamber 1 is rectangular. Figure 6 As shown, the lead plate 2 has lead holes 2c arranged in a rectangular array, the lead holes 2c are circular in shape, with a diameter of 500 μm, the number of lead holes is set according to actual needs, and the hole spacing is 5 mm. The focusing electrode plate 3 is set below the lead plate 2, and the number is three.

[0101] Preparation of gas discharge chamber: A microwave gas discharge chamber 1 is designed using high-frequency discharge and microwave discharge.

[0102] A -500V extraction voltage is applied to the extraction plate 2 to extract the array electron beam 6. A -1000V focusing voltage is applied to the first focusing electrode plate 3, a -800V focusing voltage is applied to the second focusing electrode plate 3, and a -510V focusing voltage is applied to the third focusing electrode plate 3 for focusing.

[0103] Embodiment 4

[0104] The X-ray source of this embodiment includes a discharge chamber, an extraction plate 2, a focusing electrode plate 3 and a target 4. The cross section of the gas discharge chamber 1 is circular. Figure 7 As shown, the lead plate 2 has lead holes 2d arranged in a triangular array, the lead holes 2d are triangular in shape, the side length is 1000 μm, the number of lead holes is set according to actual needs, and the hole spacing is 10 mm. The focusing electrode plate 3 is set below the lead plate 2, and the number is three.

[0105] Preparation of gas discharge chamber: High frequency discharge and radio frequency discharge are adopted to design radio frequency gas discharge chamber 1.

[0106] A negative high voltage of -1000 is applied to the lead-out plate 2 to lead out the array electron beam 6. A focus voltage of -1500V is applied to the first focus electrode plate 3, a focus voltage of -1200V is applied to the second focus electrode plate 3, and a focus voltage of -1050V is applied to the third focus electrode plate 3 for focusing.

[0107] Those skilled in the art will appreciate that all or part of the processes of the above-mentioned embodiments can be implemented by instructing related hardware through a computer program, and the program can be stored in a computer-readable storage medium, wherein the computer-readable storage medium is a disk, an optical disk, a read-only storage memory, or a random access memory, etc.

[0108] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for preparing a distributed micro-focus X-ray beam, characterized in that: The method comprises: Introducing an inert gas into a gas discharge chamber, and applying a preset power supply voltage to electrodes of the gas discharge chamber, so that the inert gas discharges to generate plasma; An extraction plate is arranged at the outlet of the gas discharge chamber, and a plurality of extraction holes are arranged on the extraction plate. By applying a preset extraction voltage on the extraction plate, the plasma is extracted from the extraction holes to form a plurality of electron beams; A focusing electrode plate is arranged below the extraction plate, and a focusing voltage with a preset potential lower than the extraction voltage is applied to the focusing electrode plate, so that each electron beam is focused through the focusing electrode plate; A target is arranged below the focusing electrode plate so that all focused electron beams bombard the target, thereby generating a distributed micro-focus X-ray beam.

2. The method according to claim 1, characterized in that The method further comprises: The intensity of the generated distributed micro-focus X-ray beam is controlled by controlling the flow rate of the inert gas introduced into the gas discharge chamber.

3. The method according to claim 1 or 2, characterized in that: The method further comprises: The intensity of the generated distributed micro-focus X-ray beam is controlled by controlling a preset extraction voltage applied to the extraction plate.

4. The method according to claim 3, characterized in that The extraction voltage has a value range of -1000V to -5V.

5. The method according to claim 1 or 2, characterized in that: The method comprises: The focus size of the generated distributed micro-focus X-ray beam is controlled by adjusting the number of the focusing electrode plates and / or the focusing voltage applied to the focusing electrode plates.

6. The method according to claim 5, characterized in that The number of the focusing electrode plate is one, and the focusing voltage applied to the focusing electrode plate has a value range of -2000-0V.

7. The method according to claim 5, characterized in that The number of the focusing electrode plates is set to three, namely a first focusing electrode plate, a second focusing electrode plate and a third focusing electrode plate; the first focusing electrode plate, the second focusing electrode plate and the third focusing electrode plate are sequentially arranged below the lead-out plate, and the first focusing electrode plate, the second focusing electrode plate and the third focusing electrode plate are arranged in parallel with equal spacing; The focusing voltage applied to the first focusing electrode plate has a value range of -1800-0V; The focusing voltage applied to the second focusing electrode plate has a value range of -2000-0V; The focus voltage applied on the third focus electrode plate has a value range of -1200-0V.

8. The method according to claim 1 or 2, characterized in that: The method further comprises: The position of each X-ray of the distributed micro-focus X-ray beam is controlled by adjusting the position of each of the lead-out holes on the lead-out plate.

9. The method according to claim 1 or 2, characterized in that: The method further comprises: The spot shape and size of the distributed micro-focus X-ray beam are controlled respectively by adjusting the shape and size of the lead-out hole.

10. The method according to claim 1 or 2, characterized in that: The method comprises: Selecting a power source type and a discharge mode of the gas discharge chamber, and designing the gas discharge chamber according to the power source type and the discharge mode; The power supply types include: DC power supply, AC power supply and high frequency power supply; The discharge modes include glow discharge, radio frequency discharge and microwave discharge.

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