JP3868322B2 - Ceramic acceleration cavity, accelerator equipped with the acceleration cavity, and method of manufacturing a ceramic acceleration cavity - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an acceleration cavity used in high energy physics or medical equipment, an accelerator including the acceleration cavity, and a method for manufacturing the acceleration cavity.
[0002]
[Prior art]
An accelerator is an apparatus that accelerates electrons, protons, and various ion-charged particles to produce high-energy particles by using electromagnetic force. The nature of nuclei and elementary particles can be investigated by colliding the beam of high-speed particles produced by this accelerator with nuclei and causing nuclear reactions or making elementary particles. In addition, the high-speed particles obtained using this accelerator are not only used in academic experiments on the nuclei and elementary particles, but also applied in various fields such as application to radiotherapy in the medical field. .
[0003]
In an experiment using an acceleration cavity, particles such as electrons are accelerated to a high energy state. Therefore, high surface conductivity is required for the acceleration cavity. The accelerator is used for experiments in which particles collide with a target. Therefore, the acceleration cavity needs to be manufactured and installed with extremely high accuracy in order to realize an accurate collision.
[0004]
[Problems to be solved by the invention]
An accelerating cavity that has a basic structure of a conventional oxygen-free copper forging has a high surface conductivity. However, since metal is a basic material, there are several factors that affect the stable acceleration of the beam.
[0005]
For example, a single electron accelerator tube has a large weight of about 100 kg, and the acceleration cavity itself has a large deflection. In addition, since the metal has the basic structure, the accuracy of the apparatus may be reduced by expansion due to temperature, and thermal stability is lacking.
[0006]
[Means for Solving the Problems]
The present invention has been made in view of the above circumstances, and aims to provide a lightweight and thermally stable acceleration cavity having high conductivity, an accelerator having the acceleration cavity, and a method for manufacturing the acceleration cavity. Yes.
[0007]
According to a first aspect of the present invention, there is provided a basic cavity that extends in a direction of acceleration of charged particles and surrounds a space for accelerating the charged particles, and a disk that gives a perturbation effect to the accelerated charged particles. Accelerating cavities in which a plurality of cells for accelerating the charged particles are formed, the accelerating cavities having an outer wall layer made of copper electroforming, and each of the basic cavities Has a tubular ceramic cavity, an active silver brazing material layer formed on the surface of the ceramic cavity, and a copper electroformed layer formed on the surface of the active silver brazing material layer, Each disk has a ceramic disk, an active silver brazing material layer formed on the surface of the ceramic disk, and a copper electroformed layer formed on the surface of the active silver brazing material layer. The basic cavity and each of the disks are the outer wall layer and Serial that are integrated by being joined with each copper electroformed layer, an acceleration cavity, wherein.
[0008]
A second aspect of the present invention is an acceleration cavity according to the first aspect, characterized in that a dummy load made of a ceramic cavity is formed at least at one end.
[0009]
The 3rd viewpoint of this invention is a high frequency accelerator which comprises the acceleration cavity which concerns on a 1st viewpoint or a 2nd viewpoint.
[0010]
A fourth aspect of the present invention is to form a basic cavity by forming an active silver brazing material layer on the surface of a tubular ceramic cavity and then forming a copper electroformed layer on the surface of the active silver brazing material layer. A disk for imparting a perturbation effect to charged particles that are accelerated by forming a copper electroforming layer on the surface of the active silver brazing material layer after forming an active silver brazing material layer on the surface of the ceramic disc And alternately connecting the basic cavity and the disk along the acceleration direction, and integrating the basic cavity and the disk by forming a copper electroformed layer on the outer wall; An acceleration cavity manufacturing method characterized by comprising:
[0011]
According to such a configuration, it is possible to provide an acceleration cavity having high conductivity, light weight and thermal stability, an accelerator having the acceleration cavity, and a method for manufacturing the acceleration cavity.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. The acceleration cavity according to the present invention can be applied to both a linear accelerator and a circular accelerator, but in the following description, a standing wave type high frequency linear accelerator will be described as an example. In the following description, components having substantially the same functions and configurations are denoted by the same reference numerals, and redundant description will be provided only when necessary.
[0013]
FIG. 1 shows a cross-sectional view of an acceleration cavity 20 constituting the high-frequency linear accelerator 10 (see FIG. 2) as seen from the side.
[0014]
In FIG. 1, the acceleration cavity 20 has a basic cavity 23, a disk 21, and an outer layer 24 made of a copper electroformed layer. That is, the acceleration cavity 20 has a structure in which basic cavities 23 and disks 21 alternately arranged along the particle acceleration direction are integrally joined by a copper electroformed layer formed on the outer wall.
[0015]
The basic cavity 23 has a ceramic cavity 200 made of SiC (silicon carbide) as its basic skeleton, and has a metal layer (hereinafter referred to as a brazing filler metal layer 201) of an active silver brazing material added with titanium on the surface thereof. Further, an oxygen-free copper layer (hereinafter, oxygen-free copper layer 202) is laminated.
[0016]
By installing the disk 21 together with the opening edge of the basic cavity 23, the inside of the acceleration cavity 20 is partitioned into n cells. This disk 21 also has a ceramic skeleton 210 made of SiC (silicon carbide) as a basic skeleton, and has a metal layer (hereinafter referred to as a brazing filler metal layer 201) of an active silver brazing material added with titanium on the surface thereof. Further, an oxygen-free copper layer (hereinafter, oxygen-free copper layer 202) is laminated. The interval between the disks 21 (that is, the length of each cell) is designed to apply a π-mode high frequency. The disk 21 gives a perturbation effect to the electromagnetic wave resonating in the acceleration cavity 20, and the inner diameter of the hole of the disk 21 affects the convergence of an accelerated particle beam incident from an injector (not shown).
[0017]
FIG. 2 is a bird's-eye view showing a part of the standing wave type high frequency linear accelerator 10 according to the present embodiment. Although the high-frequency linear accelerator 10 is slightly different depending on the required acceleration characteristics, the acceleration cavity 20 having a length of about 1 to 3 m, which is a circular tube-shaped cavity shown in FIG. 1, is provided in the axial direction (particle acceleration direction). It has a configuration with multiple connections. Although not shown in FIG. 1, the main-line accelerator includes components included in a known linear accelerator 10 such as a beam injector, a beam buncher, and a beam focusing magnet (such as a quadrupole magnet).
[0018]
Next, the principle of operation of the linear accelerator 10 will be briefly described with reference to FIGS. 1 and 2.
[0019]
A plurality of accelerating cavities 20 mounted with the centers of the holes of the disk 21 arranged coaxially are connected to form a linear accelerator 10, and the inside thereof is evacuated. This is because if there is residual gas in the beam trajectory, it collides with the beam, causing the beam to deviate from the ideal trajectory, resulting in a reduction in the number of particles in the beam and shortening the beam life. Because it will do. When a π-mode high frequency (microwave) is supplied into the linear accelerator, the high frequency causes a cavity resonance in the linear accelerator 10 as a standing wave.
[0020]
In such a setting, for example, a beam of charged particles is emitted so as to pass through the center of each disk 21 from the beam incident side to the emission side in FIG. The beam is then accelerated by the electric field generated in each cell as it passes through each cell. The length of each cell is adjusted according to the electromagnetic wave mode (in this case, π mode) in which the direction of the high frequency resonating when the accelerated beam passes through each disk 21 is just reversed. The
[0021]
By the way, in the acceleration cavity using the acceleration cavity by the conventional oxygen-free copper forging material, a peripheral device called a dummy load is separately required. The dummy load is an absorber that takes out excess high-frequency power used for particle acceleration outside the acceleration cavity and absorbs it as Joule heat. The dummy load is electrically connected to the applied high frequency, and is provided, for example, on the side surface of the acceleration cavity.
[0022]
Unlike the conventional acceleration cavity made of oxygen-free copper forging, the acceleration cavity 20 according to the present invention does not require a dummy load as a peripheral device. That is, by exposing silicon carbide in the ceramic cavity 200, which is the basic structure, at an appropriate location and using it as a dummy load, an accelerator that does not require a dummy load as the peripheral device can be realized. For example, in the acceleration cavity 20 according to the present invention, as shown in FIG. 3, a portion where the active silver brazing material layer and the copper electroforming layer are not formed can be formed in the acceleration cavity 20 to form a dummy load. . The surplus high frequency power is absorbed by the exposed SiC (silicon carbide) as the radio wave absorber.
[0023]
According to such a configuration, it is not necessary to separately provide a dummy load as a peripheral device, and the configuration of the apparatus can be simplified. In addition, since a part of SiC (silicon carbide) in the acceleration cavity 20 is used as a dummy load, the weight of the apparatus can be reduced.
[0024]
Next, a method for manufacturing the acceleration cavity 20 will be described.
[0025]
An important point of the manufacturing method according to the present invention is that the active silver brazing material layer 201 is formed between the copper electroformed layer 202 and the ceramic cavity 200, thereby manufacturing the acceleration cavity 20 in which separation does not occur at the SiC interface. In the idea to do. That is, when the copper electroformed layer 202 is formed directly on the surface of the ceramic cavity 200 by, for example, a metal vapor deposition method, the adhesive strength is insufficient at the interface of the ceramic cavity 200. Separation may occur at the interface between the cast layer 202 and the ceramic cavity 200. By this peeling, the conduction efficiency of the acceleration cavity is lowered, and the experimental accuracy is lowered.
[0026]
However, like the accelerated cavity manufacturing method according to the present invention, an accelerated cavity 20 that does not cause peeling of the copper electroformed layer is manufactured by performing the active silver brazing material application / reaction layer forming process before the copper coating process. Is possible. This is because the titanium added to the active silver brazing material causes a chemical reaction with the carbon in the SiC, thereby strengthening the adhesion between the active silver brazing material and the SiC base material surface, and peeling on the SiC base material surface. This is because no longer occurs.
[0027]
Specific means will be described below.
[0028]
The acceleration cavity 20 according to the present embodiment shown in FIG. 1 is integrally welded with a copper electroforming layer formed on the outer wall by basic cavities 23 and disks 21 arranged alternately along the particle acceleration direction. It has a structure.
[0029]
First, a manufacturing method of each basic cavity 23 and each disk 21 having the above-described layer structure will be described.
[0030]
An active silver brazing material sheet or powder to which titanium or the like is added is applied to the surface of a ceramic cavity 200 manufactured according to a predetermined design to form a layer. The thickness of the layer at this time is about 100 μm, for example. The ratio of added titanium is, for example, 1.5 to 2%.
[0031]
Next, the ceramic cavity 200 coated with the active silver brazing material is subjected to a vacuum heat treatment at a melting temperature corresponding to the brazing material component at approximately 850 ° C. for about 5 minutes in a vacuum heat treatment furnace, and the brazing material layer 201. Form. As a result, a reaction layer such as TiC between the ceramic cavity 200 and the active silver brazing material 201 is formed to ensure the interface bonding strength. The formation of the brazing filler metal layer 201 by this vacuum heat treatment is generally performed at 700 to 900.degree.
[0032]
Thereafter, the surface of the brazing material layer 201 formed by the above-described process is subjected to initial layer plating and copper electroforming treatment having a film thickness necessary for the formation of the acceleration cavity, so that the surface of the ceramic cavity 200 having the basic structure and the copper electroforming are formed. The basic cavity 23 having a configuration in which the active silver brazing material layer 201 is formed between the layer 202 and the layer 202 can be obtained.
[0033]
The disk 21 can be manufactured by the same method as the acceleration cavity 20 described above. Therefore, the description is omitted.
[0034]
Next, a process for manufacturing the acceleration cavity 20 from the basic cavity 23 and the disk 21 will be described.
[0035]
The basic cavities 23 and the disks 21 obtained as described above are alternately arranged along the particle acceleration direction while aligning with high accuracy. By performing a copper electroforming process on the outside, a copper electroformed layer 24 integrated with each copper electroformed layer 202 formed in the basic cavity 23 and the disk 21 is formed.
[0036]
Through the above steps, an acceleration cavity having a structure in which an active brazing filler metal layer and an oxygen-free copper electroformed layer are formed on the surface of the SiC substrate can be obtained.
[0037]
According to the acceleration cavity having such a configuration, it is possible to realize an acceleration cavity and an accelerator that have high electrical conductivity and are lighter than conventional acceleration cavities made of oxygen-free copper forging. For example, according to experiments by the inventors, when comparing the weight of an acceleration cavity 20 having a basic structure of SiC and a conventional acceleration cavity made of oxygen-free copper forging having the same structure as the acceleration cavity 20, The acceleration cavity 20 was 1/8 the weight of the conventional one.
[0038]
Acceleration cavity 20 has a basic structure of SiC (silicon carbide). Therefore, the expansion due to heat is less than that of an acceleration cavity formed by a conventional oxygen-free copper forging material, and a more accurate experiment can be performed.
[0039]
Further, the acceleration cavity 20 has an active silver brazing material layer between the surface of SiC (silicon carbide) and the copper electroformed layer. Therefore, it is possible to prevent peeling at the SiC interface.
[0040]
Further, as the acceleration cavity 20, a basic cavity in which SiC (silicon carbide) is exposed only on the inner side can be used as a dummy load. Therefore, it is not necessary to provide a dummy load as a separate peripheral device, and the apparatus can be simplified and reduced in weight.
[0041]
Although the present invention has been described based on the embodiments, those skilled in the art can come up with various changes and modifications within the scope of the idea of the present invention. It is understood that it belongs to the scope of the present invention. For example, as shown below, various modifications can be made without changing the gist thereof.
[0042]
In the above-described embodiment, a configuration in which the dummy load 25 exposing the ceramic in the basic cavity is provided (see FIG. 3). On the other hand, the ceramics are also exposed on the dummy load side surfaces of the disks 21 forming the cells together with the dummy load 25 (that is, the first and second disks 21 counted from the emission side in FIG. 3). May be.
[0043]
According to such a configuration, it is possible to further increase the absorption efficiency of surplus high frequencies.
[0044]
The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the invention in the implementation stage. Further, the embodiments may be combined as appropriate as possible, and in that case, the combined effect can be obtained. Furthermore, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and the effect described in the column of the effect of the invention If at least one of the following is obtained, a configuration in which this configuration requirement is deleted can be extracted as an invention.
[0045]
【The invention's effect】
As described above, according to the present invention, it is possible to realize an acceleration cavity having high electrical conductivity and being light and thermally stable, an accelerator having the acceleration cavity, and a method for manufacturing the acceleration cavity.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an acceleration cavity 20 constituting a high-frequency linear accelerator 10 as viewed from the side.
FIG. 2 is a bird's eye view showing a part of the high-frequency linear accelerator 10. FIG.
FIG. 3 shows an acceleration cavity 20 with a dummy load.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Linear accelerator 20 ... Acceleration cavity 21 ... Disk 23 ... Basic cavity 24 ... Outer layer (copper electroformed layer)
25 ... Dummy load 200 ... Ceramic cavity (SiC cavity)
201 ... Active silver brazing material layer 202 ... Copper electroformed layer 210 ... Ceramic disc

Claims (4)

By alternately arranging basic cavities extending in the acceleration direction of the charged particles and surrounding a space for accelerating the charged particles, and disks giving a perturbation effect to the accelerating charged particles along the acceleration direction An acceleration cavity formed with a plurality of cells for accelerating the charged particles,
The acceleration cavity has an outer wall layer made of copper electroforming,
Each of the basic cavities includes a tube-shaped ceramic cavity, an active silver brazing material layer formed on the surface of the ceramic cavity, and a copper electroforming layer formed on the surface of the active silver brazing material layer. Have
Each of the disks includes a ceramic disk, an active silver brazing material layer formed on the surface of the ceramic disk, and a copper electroformed layer formed on the surface of the active silver brazing material layer,
Each of the basic cavities and each of the disks are integrated by being joined by the outer wall layer and each of the copper electroformed layers,
Acceleration cavity characterized by. The acceleration cavity according to claim 1, wherein a dummy load comprising a ceramic cavity is formed at least at one end. A high-frequency accelerator comprising the acceleration cavity according to claim 1. After forming an active silver brazing material layer on the surface of the tube-shaped ceramic cavity, forming a basic cavity by forming a copper electroformed layer on the surface of the active silver brazing material layer, and a surface of the ceramic disk Forming a disk for giving a perturbation effect to charged particles that are accelerated by forming a copper electroformed layer on the surface of the active silver brazing material layer after forming the active silver brazing material layer on
Connecting the basic cavity and the disk alternately along the acceleration direction, and integrating the basic cavity and the disk by forming a copper electroformed layer on the outer wall;
An accelerating cavity manufacturing method comprising:

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