A kind of anti-sputtering faraday cup and its preparation method

Abstract

The present invention relates to an anti-sputtering Faraday cage, comprising a bias electrode, a collecting electrode, an aperture and a shielding cylinder. The bias electrode is formed into a cylindrical shape with two ends open, and a first flange extending outward is formed on the top of the bias electrode. The collecting electrode is formed into a cylindrical shape, with an open top and a closed bottom. The aperture is cylindrical, and the aperture is sleeved on the outside of the bias electrode, and the bias electrode is fixed to the inner wall of the aperture through the first flange. The bottom end of the shielding cylinder is closed, and the shielding cylinder is sleeved on the outside of the collecting electrode. The collecting electrode is fixed to the inner wall of the shielding cylinder through the second electrode, and the bottom of the shielding cylinder is separated from the bottom end of the collecting electrode. The bias electrode and the collecting electrode and the ground are insulated by vacuum, and only a small part of the ceramic is away from the beam itself and the sputtering beam path, thereby effectively solving the ceramic pollution problem.

Description

Technical Field

[0001] The invention relates to the field of charged particle beam measurement, and in particular to an anti-sputtering Faraday cage and a preparation method thereof. Background Art

[0002] A Faraday cage is a basic device for measuring the intensity of a charged particle beam. Its purpose is to measure the intensity of the beam by intercepting a charged ion beam and collecting its charge.

[0003] The bias electrode and the collecting electrode of the existing Faraday cup are insulated from each other and from the ground by insulating ceramics. The main problem with this technology is that the insulating ceramics are easily contaminated by the particle beam itself and the sputtering beam it generates, which causes the insulation performance between the bias electrode and the collecting electrode and the insulation performance to the ground to decrease, resulting in difficulty in bias loading and inaccurate beam intensity measurement, which is also the main bottleneck affecting the measurement accuracy of this Faraday cup. Summary of the invention

[0004] In view of the above problems, the purpose of the present invention is to provide a sputtering-proof Faraday cage that does not require a large area of ​​insulating ceramics. The bias electrode and the collecting electrode and the ground are insulated by vacuum, and only a small part of the ceramics is away from the beam itself and the sputtering beam path, thereby effectively solving the ceramic contamination problem.

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

[0006] One aspect of the present invention provides a sputtering-proof Faraday cage, comprising:

[0007] A bias electrode, wherein the bias electrode is formed into a cylindrical shape with two ends opened, and a first flange extending outward is formed on the top of the bias electrode;

[0008] A collecting electrode, the collecting electrode is formed in a cylindrical shape, the top end of the collecting electrode is open, the bottom end is closed, a second flange extending outward is formed at the bottom of the collecting electrode, the collecting electrode is located directly below the bias electrode, and the top end of the collecting electrode is separated from the bottom end of the bias electrode to form a vacuum insulation layer;

[0009] An aperture, the aperture is cylindrical, the aperture is sleeved on the outside of the bias electrode, and the bias electrode is fixed to the inner wall of the aperture through the first flange;

[0010] A support electrode, wherein the bias electrode is fixedly mounted on the top of the support electrode through a first ceramic and a first screw;

[0011] A shielding cylinder, the bottom end of which is closed, the shielding cylinder is sleeved on the outside of the collecting electrode, the collecting electrode is fixed to the inner wall of the shielding cylinder through the supporting electrode, and the bottom of the shielding cylinder is separated from the bottom end of the collecting electrode.

[0012] Furthermore, it also includes a supporting electrode, which is cylindrical and is sleeved on the outside of the bias electrode and the collecting electrode. The first flange and the top of the supporting electrode are separated and fixedly connected by a first ceramic, and the second flange and the bottom of the supporting electrode are separated and fixedly connected by a second ceramic. The top and bottom of the supporting electrode are respectively fixedly mounted on the inner sides of the aperture and the shielding tube.

[0013] Furthermore, the first flange is connected to the top of the supporting electrode via a first screw, the first screw passes through the first flange, the first ceramic and the top of the supporting electrode are fixedly connected, and the first ceramic and the vacuum insulation layer are staggered.

[0014] Furthermore, the second flange is connected to the bottom of the supporting electrode via a second screw, the second screw passes through the second flange, the second ceramic is fixedly connected to the bottom of the supporting electrode, and the second ceramic is staggered with the vacuum insulation layer.

[0015] Furthermore, the bottom of the supporting electrode is fixedly connected to the shielding tube via a third screw, the top of the supporting electrode is fixedly connected to the aperture via a fourth screw, and the bottom of the shielding tube is separated from the bottom end of the collecting electrode.

[0016] Furthermore, a beam inflow hole is formed at the top of the aperture.

[0017] Furthermore, the bias electrode and the collecting electrode are both made of oxygen-free copper material.

[0018] Furthermore, the supporting electrode, the aperture and the shielding tube are all made of stainless steel.

[0019] Furthermore, the width between the vacuum insulation layers is 5 mm, and the interval between the bottom end of the collecting electrode and the shielding cylinder is 5 mm.

[0020] Another aspect of the present invention further provides a method for preparing the sputtering-proof Faraday cage, comprising the steps of:

[0021] The bias electrode is fixedly mounted on the top of the support electrode through the first ceramic and the first screw;

[0022] The collecting electrode is fixedly mounted on the bottom of the supporting electrode through the second ceramic and the second screw, so that the bias electrode and the collecting electrode are separated;

[0023] The shielding cylinder is sleeved outside the collecting electrode and fixedly mounted on the bottom of the supporting electrode by the third screw, so that the bottom end of the shielding cylinder is separated from the bottom end of the collecting electrode;

[0024] The aperture is sleeved outside the bias electrode and fixedly mounted on the top of the supporting electrode by the fourth screw.

[0025] The present invention adopts the above technical solution, which has the following advantages:

[0026] The bias electrode and the collecting electrode in the present invention are separated to form a vacuum insulation layer, and the vacuum insulation makes the insulation resistance value between the two high voltage 100MΩ; the collecting electrode and the shielding tube are separated to form a vacuum insulation, and the insulation resistance value between the two is higher than 100MΩ.

[0027] The entire device does not require a large area of ​​insulating ceramics. Only a small part of the ceramics is far away from the beam itself and the sputtering beam path, which can improve the measurement accuracy of the Faraday cup. There is no need to frequently replace the insulating ceramics, making the Faraday cup more durable.

[0028] The sputter-proof Faraday cup device of the present invention can be applied in the field of particle beam cancer treatment for beam adjustment before treatment. The Faraday cup device is easy to operate, easy to maintain, durable and has accurate measurement, so that it can be used as a fast and accurate beam adjustment device. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the following detailed description of the preferred embodiment.The drawings are only for the purpose of illustrating the preferred embodiments and are not to be construed as limiting the invention.

[0030] Throughout the drawings, the same reference numerals are used to denote the same components. In the drawings:

[0031] Figure 1 It is a schematic diagram of the structure of the sputter-proof Faraday cage;

[0032] The symbols in the accompanying drawings are as follows:

[0033] 101 - bias electrode, 102 - collecting electrode, 103 - supporting electrode, 104 - aperture, 105 - shielding tube, 201 - first ceramic, 202 - second ceramic, 301 - first screw, 302 - second screw, 303 - third screw, 304 - fourth screw. DETAILED DESCRIPTION

[0034] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0035] An embodiment of the present invention provides a sputtering-proof Faraday cage, comprising a bias electrode, a collecting electrode, an aperture and a shielding cylinder. The bias electrode is formed into a cylindrical shape with two ends open, and a first flange extending outward is formed on the top of the bias electrode. The collecting electrode is formed into a cylindrical shape, with an open top and a closed bottom, and a second flange extending outward is formed on the bottom of the collecting electrode. The collecting electrode is located directly below the bias electrode, and a vacuum insulation layer is formed between the top of the collecting electrode and the bottom of the bias electrode. The aperture is cylindrical, and the aperture is sleeved on the outside of the bias electrode, and the bias electrode is fixed to the inner wall of the aperture through the first flange. The bottom end of the shielding cylinder is closed, and the shielding cylinder is sleeved on the outside of the collecting electrode. The collecting electrode is fixed to the inner wall of the shielding cylinder through the supporting electrode, and the bottom of the shielding cylinder is separated from the bottom end of the collecting electrode. The bias electrode and the collecting electrode and the ground are insulated by vacuum, and only a small part of the ceramic is away from the beam itself and the sputtering beam path, thereby effectively solving the ceramic pollution problem.

[0036] Example 1

[0037] like Figure 1 The sputter-proof Faraday cage provided in Example 1 of the present invention includes a bias electrode 101, a collecting electrode 102, an aperture 104 and a shielding tube 105. The bias electrode 101 suppresses secondary electrons by loading a bias voltage, thereby making the current intensity measurement more accurate. The collecting electrode 102 is used to block and collect all incident beams and export the charge to the data acquisition device. The aperture 104 is used to protect the bias electrode 101 to prevent the beam from directly bombarding the bias electrode 101. The shielding tube 105 is used to isolate the complex external electromagnetic environment to ensure that the measurement value is accurate and the noise is small. The bias electrode 101 includes a cylindrical shape with openings at both ends and a first flange extending outward from the top. A first threaded hole is provided on the front, back, left and right sides of the first flange. The bias electrode 101 is preferably made of oxygen-free copper material, and the inner diameter of the bias electrode is 60 mm, and the outer diameter of the first flange is 80 mm.

[0038] The collecting electrode 102 is formed in a cylindrical shape, with an open top and a closed bottom. A second flange extending outward is formed at the bottom of the collecting electrode 102. The collecting electrode 102 is located directly below the bias electrode 101. When installed, the top of the collecting electrode 102 is separated from the bottom of the bias electrode 101 to form a vacuum insulation layer. The width of the vacuum insulation layer is preferably 5 mm. The collecting electrode 102 is preferably made of oxygen-free copper material. The inner diameter of the collecting electrode 102 is 60 mm, and the outer diameter of the second flange is 80 mm. A second threaded hole is provided at the front, back, left, and right sides of the second flange.

[0039] In the present invention, a vacuum insulation layer is formed by separating the top of the collecting electrode 102 from the bottom of the bias electrode 101. The vacuum insulation method can reduce the use of ceramics, avoid sputtering contamination of ceramics, and improve the measurement accuracy of the beam.

[0040] The support electrode 103 is cylindrical and is sleeved on the outside of the bias electrode 101 and the collecting electrode 102. The first flange is separated and fixedly connected to the top of the support electrode 103 by the first ceramic 201, and the second flange is separated and fixedly connected to the support electrode 103 by the second ceramic 202. The top and bottom of the support electrode 103 are respectively formed with a third flange and a fourth flange extending outward. The support electrode 103 is preferably made of stainless steel. The inner diameter of the support electrode 103 is 72 mm, and the outer diameters of the third flange and the fourth flange are 80 mm. The bias electrode 101 is fixedly connected to the third flange by the first screw 301 passing through the first threaded hole and the first ceramic 201 in sequence. The collecting electrode 102 is fixedly connected to the second ceramic 202 and the fourth flange by the second screw 302 passing through the second threaded hole in turn. At the same time, a gap of 5 mm is made between the bottom of the bias electrode 101 and the top of the collecting electrode 102 to form a vacuum insulation layer. The use of vacuum insulation can reduce the use of ceramics, avoid sputtering contamination of ceramics, and improve the measurement accuracy of the beam.

[0041] It should be noted that the first flange, the third flange and the first ceramic 201 are not limited to being connected by screws, but may also be connected by bonding or other connection methods well known in the art.

[0042] The aperture 104 is cylindrical and is sleeved on the outside of the bias electrode 101. The top of the aperture 104 is provided with an incident hole. The aperture 104 is preferably made of stainless steel, with an inner diameter of 50 mm for the incident hole and an inner diameter of 85 mm for the tube. The side walls of the aperture 104 are each provided with a threaded hole.

[0043] The bottom end of the shielding tube 105 is closed, and the shielding tube 105 is sleeved on the outside of the collecting electrode 102. The collecting electrode 102 is fixed to the inner wall of the shielding tube 105 through the supporting electrode. The bottom of the shielding tube 105 is separated from the bottom end of the collecting electrode 102 by a distance of 5 mm. The shielding tube 105 is preferably made of stainless steel, and the inner diameter of the tube is 85 mm. The bottom of the supporting electrode 103 is fixedly connected to the shielding tube 105 by a third screw 303, and the top of the supporting electrode 103 is fixedly connected to the aperture 104 by a fourth screw 304. The bottom of the shielding tube 105 is separated from the bottom end of the collecting electrode 102.

[0044] The bias electrode 101 and the collecting electrode 102 in the present invention are separated to form a vacuum insulation layer, and the insulation resistance value between the two is high 100MΩ through vacuum insulation; the collecting electrode 102 and the shielding tube 105 are separated to form vacuum insulation, and the insulation resistance value between the two is higher than 100MΩ.

[0045] The entire device does not require a large area of ​​insulating ceramics, only a small part of ceramics, and the ceramic parts are far away from the beam itself and the sputtering beam path, which can improve the measurement accuracy of the Faraday cup. There is no need to frequently replace the insulating ceramics, making the Faraday cup more durable.

[0046] The method for preparing the sputtering-proof Faraday cage comprises the steps of:

[0047] The bias electrode 101 is fixedly mounted on the top of the support electrode 103 through the first ceramic 201 and the first screw;

[0048] The collecting electrode 102 is fixedly mounted on the bottom of the supporting electrode 103 through the second ceramic 202 and the second screw, so that the bias electrode 101 and the collecting electrode 102 are separated;

[0049] The shielding tube 105 is sleeved outside the collecting electrode 102 and fixedly mounted on the bottom of the supporting electrode 103 by the third screw, so that the bottom end of the shielding tube 105 is separated from the bottom end of the collecting electrode 102;

[0050] The aperture 104 is sleeved outside the bias electrode 101 and fixed on the top of the supporting electrode 103 by the fourth screw.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A sputtering-proof Faraday cage, characterized in that: include: A bias electrode, wherein the bias electrode is formed into a cylindrical shape with two ends opened, and a first flange extending outward is formed on the top of the bias electrode; A collecting electrode, the collecting electrode is formed in a cylindrical shape, the top end of the collecting electrode is open, the bottom end is closed, a second flange extending outward is formed at the bottom of the collecting electrode, the collecting electrode is located directly below the bias electrode, and the top end of the collecting electrode is separated from the bottom end of the bias electrode to form a vacuum insulation layer; An aperture, wherein the aperture is cylindrical and is sleeved on the outer side of the bias electrode, and the bias electrode is fixed to the inner wall of the aperture through the first flange; A support electrode, wherein the bias electrode is fixedly mounted on the top of the support electrode through a first ceramic and a first screw; A shielding cylinder, the bottom end of which is closed, the shielding cylinder is sleeved on the outside of the collecting electrode, the collecting electrode is fixed to the inner wall of the shielding cylinder through the second flange, and the bottom of the shielding cylinder is separated from the bottom end of the collecting electrode; The bias electrode and the collecting electrode are both made of oxygen-free copper material; The supporting electrode, the aperture and the shielding tube are all made of stainless steel.

2. The anti-sputtering Faraday cage according to claim 1, characterized in that: The supporting electrode is cylindrical and is sleeved on the outside of the bias electrode and the collecting electrode. The first flange is separated and fixedly connected to the top of the supporting electrode by a first ceramic, and the second flange is separated and fixedly connected to the bottom of the supporting electrode by a second ceramic. The top and bottom of the supporting electrode are respectively fixedly mounted on the inner sides of the aperture and the shielding tube.

3. The anti-sputtering Faraday cage according to claim 2, characterized in that: The first flange is connected to the top of the supporting electrode via a first screw. The first screw passes through the first flange and the first ceramic is fixedly connected to the top of the supporting electrode. The first ceramic is staggered with the vacuum insulation layer.

4. The anti-sputtering Faraday cage according to claim 2, characterized in that: The second flange is connected to the bottom of the supporting electrode via a second screw. The second screw passes through the second flange and the second ceramic is fixedly connected to the bottom of the supporting electrode. The second ceramic is staggered with the vacuum insulation layer.

5. The anti-sputtering Faraday cage according to claim 2, characterized in that: The bottom of the supporting electrode is fixedly connected to the shielding cylinder via a third screw, and the top of the supporting electrode is fixedly connected to the aperture via a fourth screw.

6. The anti-sputtering Faraday cage according to claim 1, characterized in that: A beam inlet aperture is formed at the top of the aperture.

7. The sputtering-proof Faraday cage according to claim 1, characterized in that: The width between the vacuum insulation layers is 5 mm, and the interval between the bottom end of the collecting electrode and the shielding cylinder is 5 mm.

8. A method for preparing the sputtering-proof Faraday cage according to claim 5, characterized in that: Includes steps: The collecting electrode is fixedly mounted on the bottom of the supporting electrode through the second ceramic and the second screw, so that the bias electrode and the collecting electrode are separated; The shielding cylinder is sleeved outside the collecting electrode and fixedly mounted on the bottom of the supporting electrode by the third screw, so that the bottom end of the shielding cylinder is separated from the bottom end of the collecting electrode; The aperture is sleeved outside the bias electrode and fixedly mounted on the top of the supporting electrode by the fourth screw.

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