CN213482465U - Non-bias Faraday cylinder device used in atmospheric environment - Google Patents

Abstract

The utility model belongs to the technical field of charged particle beam detects, a no bias voltage Faraday's section of thick bamboo device that uses under atmospheric environment is related to, include: the beam current collecting device comprises a film electrode, a grounding fastening ring, a signal collecting electrode, a three-coaxial connector and a grounding electrode, wherein the film electrode is fixed on the signal collecting electrode through the grounding fastening ring and is tightly attached to the signal collecting electrode, a beam current incident surface and a beam current emergent surface of the film electrode are insulated, a signal output end of the signal collecting electrode is connected with a signal end of the three-coaxial connector, and the grounding fastening ring is connected with a grounding end of the three-coaxial connector through the grounding electrode. The beam current detector can be directly used in the atmospheric environment, vacuum and bias equipment are not needed, the cost is low, the size is small, the beam current is not easy to leak, and the detection result is more accurate.

Description

Non-bias Faraday cylinder device used in atmospheric environment

Technical Field

The utility model relates to a no bias voltage Faraday cage device that uses under atmospheric environment belongs to charged particle beam and detects technical field.

Background

The Faraday cup is a basic device for measuring the beam current intensity of charged particles, and aims to realize the beam current intensity measurement by intercepting charged ion beams and collecting charges of the charged ion beams.

The existing faraday cages are all used in a high vacuum environment, and a bias device is also needed to inhibit the escape of secondary electrons. The prior art faraday cages typically include: the vacuum pump comprises a sealing flange, a vacuum conduction device, a bias ring and a bias power supply. Because of the need for a relatively high vacuum environment, conventional faraday cup assemblies are generally complex in construction, bulky in size, and expensive to manufacture. Meanwhile, the introduction of a bias power supply causes bias current to leak into beam current intensity, so that the measured value is inaccurate, especially for low-energy high-intensity beams, the sputtering effect is serious, so that insulating ceramics between the bias ring and the signal electrode are polluted, and the leakage current is larger.

Disclosure of Invention

To the above problem, the utility model aims at providing a no bias voltage Faraday cylinder device of using under atmospheric environment, it can directly use in atmospheric environment, need not vacuum and bias voltage equipment, and is with low costs, small, and the beam current is difficult for revealing, and the testing result is more accurate.

In order to achieve the purpose, the utility model adopts the following technical proposal: an unbiased faraday cup apparatus for use in an atmospheric environment, comprising: the beam current collecting device comprises a film electrode, a grounding fastening ring, a signal collecting electrode, a three-coaxial connector and a grounding electrode, wherein the film electrode is fixed on the signal collecting electrode through the grounding fastening ring and is tightly attached to the signal collecting electrode, a beam current incident surface and a beam current emergent surface of the film electrode are insulated, a signal output end of the signal collecting electrode is connected with a signal end of the three-coaxial connector, and the grounding fastening ring is connected with a grounding end of the three-coaxial connector through the grounding electrode.

Furthermore, the beam incident surface of the film electrode is plated with a conductive material, and the beam emergent surface is made of an insulating material.

Furthermore, the beam emergent surface is also plated with a conductive material, but the conductive material on the beam emergent surface is not conducted with the conductive material on the beam incident surface.

Further, the grounding electrode is arranged coaxially with the signal collecting electrode, and the grounding electrode is arranged outside the signal collecting electrode and is spaced from the signal collecting electrode.

Furthermore, a protective electrode is arranged between the grounding electrode and the signal collecting electrode, the protective electrode and the signal collecting electrode are coaxially arranged, and the output end of the protective electrode is connected with the protective grounding end of the three-coaxial connector.

Further, the guard electrode and the signal collection electrode are equal in potential.

Further, coaxial insulating rings are arranged among the grounding electrode, the signal collecting electrode and the protective electrode, so that mutual insulation among the three electrodes is guaranteed.

Further, the chamfer of the one end of the signal collecting electrode in contact with the film is a fillet, and one side of the grounding fastening ring in contact with the film electrode is arranged to be arc-shaped matched with the radian of the fillet so as to ensure that the film electrode is attached to the signal collecting electrode.

Further, the faraday cup apparatus can be used for particle beam cancer therapy.

The utility model also discloses a no bias voltage Faraday's section of thick bamboo device's installation method of using under atmospheric environment for any kind of no bias voltage Faraday's section of thick bamboo device of using under atmospheric environment of installation above-mentioned, including following step: s1 inserting a first polyethylene ring into the bottom of the ground electrode, then inserting a guard electrode into the first polyethylene ring, inserting a second polyethylene ring into the guard electrode, and fastening the second polyethylene ring to the ground electrode; s2 inserting the signal collecting electrode into the second polyethylene ring, laying the film electrode on the signal collecting electrode, covering the grounding fastening ring, and fixing the grounding fastening ring on the top of the grounding electrode; s3, welding the lead-out signal wire of the signal collecting electrode with the signal end of the three-coaxial connector, welding the lead-out wire of the protective electrode with the protective ground end of the three-coaxial connector, and welding the lead-out wire of the ground electrode with the ground end of the three-coaxial connector to obtain the non-bias Faraday cylinder device used in the atmospheric environment.

The utility model discloses owing to take above technical scheme, it has following advantage:

1. the utility model discloses well device can be used for measuring charged particle beam intensity under the atmospheric environment, removal that can be very convenient, consequently can put on the route of any beam process, and need not to install on the mounting flange mouth like the Faraday cylinder for the vacuum.

2. The utility model discloses well device does not need extra biasing ring design and bias voltage equipment, can show the economic cost who reduces Faraday's section of thick bamboo.

3. The utility model discloses well device can measure energy and be less than 400MeV/u, and the number of particles per second is at the charged particle beam of 1E6 ~ 1E8 scope.

4. The utility model discloses well device can use in the particle beam field of treating cancer for dose verification before the treatment begins, low cost, easy operation, easy maintenance make this Faraday cylinder device can regard as a quick, accurate dose verification means.

Drawings

Fig. 1 is a schematic structural diagram of a non-biased faraday cup apparatus used in an atmospheric environment according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a triple coaxial connector according to an embodiment of the present invention.

Reference numerals:

1-a thin film electrode; 2-a ground fastening ring; 3-a signal collecting electrode; 4-three coaxial connectors; 41-signal terminal; 42-ground; 43-protection of ground; 5-a ground electrode; 6-a guard electrode; 7-a first polyethylene ring; 8-second polyethylene ring.

Detailed Description

The present invention is described in detail by way of specific embodiments in order to enable those skilled in the art to better understand the technical direction of the present invention. It should be understood, however, that the detailed description is provided for a better understanding of the invention only and that they should not be taken as limiting the invention. In describing the present invention, it is to be understood that the terminology used is for the purpose of description only and is not intended to be interpreted as indicating or implying any relative importance.

The embodiment discloses a non-bias faraday cup device used in atmospheric environment, as shown in fig. 1 and 2, comprising: the thin film electrode 1 is fixed on the signal collecting electrode 3 through the grounding fastening ring 2 and is tightly attached to the signal collecting electrode 3, a beam incident surface and a beam emergent surface of the thin film electrode 1 are insulated, a signal output end of the signal collecting electrode 3 is connected with a signal end 41 of the three-coaxial connector 4, the grounding fastening ring 2 is connected with a grounding end 42 of the three-coaxial connector 4 through the grounding electrode 5, and the three-coaxial connector 4 is used for leading out signals. The thin film electrode 1 can isolate the entry of secondary charged particles contained in the atmosphere ionized by the charged particles, and ensure the accuracy of flow intensity measurement. Meanwhile, the thin film electrode 1 can suppress secondary electrons generated by the signal collecting electrode 3, as well as the faraday cage bias effect used in a high vacuum environment.

The beam incident surface of the film electrode 1 is plated with a conductive material, and the beam emergent surface is made of an insulating material. The beam emergent surface can also be plated with a conductive material, but the conductive material on the beam emergent surface is not conducted with the conductive material on the beam incident surface. The thin film electrode 1 used in this example is a kempton film with a single aluminum-plated surface, the film thickness is 50um, the aluminum layer thickness is 1um, and the diameter is 85 mm.

The grounding fastening ring 2 is supported by oxygen-free copper, the diameter of the particle beam incident aperture is 62.5mm, the outer diameter is 100mm, and the top of the particle beam incident aperture is provided with four M4 threaded holes which are used for fixing the grounding electrode 5 on the grounding fastening ring 2 through screws. One side of the grounding fastening ring 2 contacting the film electrode 1 is set to be arc-shaped and tightly matched with the circular arc radian so as to ensure that the film electrode 1 is attached to the signal collecting electrode 3 and play a role in tightening the film electrode 1. Wherein the radius of the circular arc is 5 mm.

The signal collecting electrode 3, which is used to block the charged particle beam, therefore needs to be thicker than the range of the particle beam in the material. For 400MeV/u of carbon ions (12C6+), the electrode was 120mm thick and 75mm in diameter. The electrode material is oxygen-free copper. The chamfer of one side of cover film electrode 1 is the fillet, and this fillet radius is 5mm, and this fillet design is used for cooperating ground connection tighrening ring 2, thereby both tighten and flatten film electrode 1 through the press fit. The bottom of the signal collecting electrode 3 is provided with a threaded hole M4 for leading out a signal wire, and the led out signal wire is welded with the signal end 41 of the three-coaxial connector 4.

The ground electrode 5 is disposed coaxially with the signal collecting electrode 3, and the ground electrode 5 is disposed outside the signal collecting electrode 3 and spaced apart from the signal collecting electrode 3. A protective electrode 6 is arranged between the grounding electrode 5 and the signal collecting electrode 3, the protective electrode 6 and the signal collecting electrode 3 are coaxially arranged, and the output end of the protective electrode is connected with a protective grounding end 43 of the three-coaxial connector 4. The protective electrode 6 is at the same potential as the signal collecting electrode 3, so that the accuracy of the technology for weak current intensity measurement is ensured. The material of the guard electrode 6 is stainless steel, the inner diameter is 38.25mm, the outer diameter is 39.25mm, the height is 125mm, and the gap between the guard electrode and the signal collecting electrode 3 is 3 mm. Coaxial insulating rings are arranged among the grounding electrode 5, the signal collecting electrode 3 and the protective electrode 6 so as to ensure that the three electrodes are mutually insulated. The insulating ring is preferably a polyethylene ring.

The grounding electrode 5 is made of aluminum, has an inner diameter of 45mm, an outer diameter of 48mm and a height of 153mm, is separated from the guard electrode 6 by 4.75mm, and is fastened with the guard electrode 6 through M4 screws.

The utility model discloses well Faraday's section of thick bamboo device's theory of operation does: when the charged particles are incident into the atmosphere, the charged particles ionize the atmosphere to generate electron ion pairs, namely secondary particles, and if the secondary particles are not excluded, the accuracy of the Faraday cage on beam intensity measurement is affected. The faraday cup used in the vacuum environment reduces the generation of secondary particles to the maximum possible by the high vacuum environment. Under atmospheric environment, the utility model provides a film electrode can block secondary particle entering Faraday cup collecting electrode, because film electrode is conducting material and switches on with telluric electricity field at the beam incident surface, therefore these electrified secondary particles can not flow in the collector, ensure that atmospheric environment can not cause the influence to the measurement. Meanwhile, the thin film electrode can also inhibit secondary electrons generated by the signal collecting electrode. The film electrode is tightly attached to the signal collecting electrode, and the tightly attached surface is an insulator or a conductor. In the case of an insulator, secondary electrons generated when a beam is incident on the signal collecting electrode drift to the insulating layer with very low energy, accumulate on the surface of the insulating layer for a short time, and are then quickly conducted away by the signal collecting electrode, thereby playing a role in suppressing the secondary electrons. A certain amount of secondary electrons are generated on the surface of the insulating layer and drift to the signal collecting electrode, but due to the non-conductivity of the insulating layer, the escape of the secondary electrons will inevitably cause the insulating layer to present positive electricity, at the moment, the electrons of the signal collecting electrode will be transferred to the insulating layer, and the insulating layer will recover to be electrically neutral again, the electric charges transferred in two directions are equal, and it can be seen that the secondary electrons generated on the surface of the insulating layer will not affect the measurement. In the case of a thin film electrode being a conductor, the conductor and the signal collecting electrode can be considered as being integral, and therefore, this case can also be considered as a special case of a thin film electrode being an insulator on the close contact surface, and there is no principle difference between the two cases. In use, the faraday cup assembly is positioned in a beam passing region, such as a beam cancer treatment terminal, with the beam center as aligned as possible with the axis of the faraday cup. And then connecting the three-coaxial interface on the Faraday cylinder with the three-coaxial interface of the measuring instrument through a three-coaxial cable. The user can monitor the beam current intensity in real time through the measuring instrument.

All the components in the embodiment can be directly used in the atmospheric environment, the Faraday cylinder device can be used for particle beam cancer treatment, vacuumizing is not needed, the use cost of the Faraday cylinder device is reduced, the problem of current leakage is avoided because bias equipment is not needed, and the detection precision is improved.

Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications and equivalents of the embodiments of the invention may be made without departing from the spirit and scope of the invention, which should be construed as falling within the scope of the claims of the invention. The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims (9)

1. An unbiased faraday cup apparatus for use in an atmospheric environment, comprising: a film electrode, a grounding fastening ring, a signal collecting electrode, a three-coaxial connector and a grounding electrode,

the thin film electrode is fixed on the signal collecting electrode through the grounding fastening ring and is tightly attached to the signal collecting electrode, the beam incident surface and the beam emergent surface of the thin film electrode are insulated, the signal output end of the signal collecting electrode is connected with the signal end of the three-coaxial connector, and the grounding fastening ring is connected with the grounding end of the three-coaxial connector through the grounding electrode.

2. The unbiased faraday cup device for use in atmospheric conditions as in claim 1, wherein the beam incident surface of the thin film electrode is coated with a conductive material and the beam exit surface is an insulating material.

3. The unbiased faraday cup device for use in atmospheric conditions as in claim 2, wherein the beam exit face is also plated with a conductive material, but the conductive material on the beam exit face is not in conductive communication with the conductive material on the beam entrance face.

4. The unbiased faraday cage device for use in atmospheric conditions as claimed in claim 1, wherein said ground electrode is disposed coaxially with said signal collection electrode, said ground electrode being disposed outside of, and spaced from, said signal collection electrode.

5. The unbiased faraday cage device for use in atmospheric conditions as claimed in claim 4, wherein a guard electrode is disposed between the ground electrode and the signal collection electrode, the guard electrode being disposed coaxially with the signal collection electrode and having an output terminal connected to a guard terminal of the triple-coaxial joint.

6. The unbiased faraday cup device for use in atmospheric conditions as in claim 5, wherein the guard electrode and the signal collection electrode are at equal potential.

7. The unbiased faraday cage device for use in atmospheric conditions as claimed in claim 6, wherein coaxial insulating rings are provided between the grounding electrode, the signal collecting electrode and the shielding electrode to ensure mutual insulation between the three electrodes.

8. The unbiased faraday cup device for use in atmospheric conditions as claimed in claim 1, wherein an end of the signal collecting electrode in contact with the thin film electrode is chamfered with a rounded corner.

9. The unbiased faraday cup device for use in atmospheric conditions as claimed in claim 8, wherein a side of the grounding fastening ring in contact with the film electrode is configured as a circular arc matching the rounded arc to ensure that the film electrode is in contact with the signal collecting electrode.

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