JPH07111197A - Connection structure for vacuum chamber in particle accelerator - Google Patents

Abstract

PURPOSE:To provide an effective connection structure to connect vacuum chambers comprising copper material to each other. CONSTITUTION:In connecting vacuum chambers 20, 20 comprising copper material to each other, a groove 32 is formed in an outer circumferential surface of a forward end part of a tubular coupling main body 31 formed of the same copper material as that of the vacuum chambers, and a ring body 33 comprising stainless material is engaged in the groove. A flange 34 comprising stainless material similarly is fixed to the ring body to obtain a coupling 30. Base ends of the couplings 30 are welded to be jointed with connection ends of the subject vacuum chambers to be connected to each other respectively, and the flanges 34 of the couplings 30 are fastened to each other to connect the vacuum chambers to each other. Otherwise, the coupling is provided with a circular rib instead of the flange, so by welding the ribs with each other, the vacuum chambers are connected to each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for connecting vacuum chambers in a particle accelerator such as a synchrotron.

[0002]

2. Description of the Related Art In recent years, SOR light (synchrotron radiation) emitted from a particle accelerator such as a synchrotron is extracted and used as a light source, for example, in the manufacture of VLSI, diagnosis in the medical field, molecular analysis, structural analysis, etc. There is momentum to use it in various fields, and facilities for it are being developed.

FIG. 3 shows an outline of a small synchrotron for utilizing SOR light. In this synchrotron, electrons generated by an electron generator 1 such as an electron gun are accelerated by a linear accelerator (linac) 2 to near the speed of light, deflected by a deflecting electromagnet 3, and accumulated by an incident path 4 via an inflector 5. It is incident on the ring 6. The electrons that have entered the storage ring 6 are converged by the converging electromagnet 8 while being given energy by the high-frequency acceleration cavity 7, are deflected by the deflection electromagnet 9, and continue to orbit the storage ring 6. Then, when deflected by the deflecting electromagnet 9, SOR light is emitted in the tangential direction thereof, and the SOR light is emitted to the exposure device 11 through the beam line 10 which is a light extraction line for use.

The storage ring 6 is formed in an annular shape by connecting a number of vacuum chambers of a predetermined length. Aluminum alloy has been generally used as a material of the vacuum chamber for forming the storage ring 6, and the connection between the vacuum chambers sufficiently secures the vacuum sealing performance of the connection portion, and It has heretofore been common practice to directly weld one end of a vacuum chamber to one another in order to minimize steps and gaps that are unavoidably generated on the inner surface side of the vacuum chamber.

[0005]

By the way, recently, a large-scale and high-power particle accelerator has been developed, and in such a particle accelerator, copper, which is superior in heat resistance and electric characteristics to an aluminum alloy, is used. It is considered to use the material as the material of the vacuum chamber,
In order to enable the adoption of such a vacuum chamber, it was essential to develop an effective connection structure for connecting the vacuum chambers made of those copper materials.

That is, as described above, it is possible to directly weld and connect the aluminum alloy vacuum chambers to each other without any problem, but to weld the copper materials, the aluminum alloys are welded to each other. A higher temperature is required than in the case, and when welding is simply performed in the atmosphere, the periphery of the welded portion (in particular, the inner surface of the vacuum chamber) is oxidized and the performance as a vacuum chamber cannot be ensured. Therefore, when welding is intentionally performed, it is inevitable to maintain the vacuum in the entire periphery of the welded part including the inner surface side of the vacuum chamber in order to prevent oxidation. It is not possible to perform the work of connecting and forming a large-scale annular storage ring in a vacuum atmosphere, and after welding, it is impossible to perform post-treatment on the inner surface of the weld. As such, such things are almost unrealistic.

Therefore, as a practical method, a flange 21 made of a stainless material is attached to the vacuum chamber 20 made of a copper material and the flanges 21 and 21 are fastened to each other by the structure shown in FIG. 4 or 5. By doing so, it is considered that the vacuum chambers 20, 20 are connected to each other.

In the structure shown in FIG. 4, an intermediate layer 22 is formed by depositing Inconel or the like on the outer surface of a vacuum chamber 20 made of a copper material, and a flange 21 made of a stainless material is welded on the surface. It is a thing.

Further, in the structure shown in FIG. 5, the base portion 24 made of a copper material and the tip portion 25 made of a stainless material are joined by, for example, crimping, and the tip portion 25 is also made of the above-mentioned flange 2 made of a stainless material.
A dissimilar material joint 26 formed by welding 1
6 is welded to the tip of the vacuum chamber 20 for use. Vacuum chamber 2 of this dissimilar material joint 26
Since joining to 0 is performed by welding copper materials to each other, the welding is performed in a vacuum atmosphere, for example, in a vacuum vessel, and post-treatment is performed on the inner surface of the welded portion after welding if necessary.

However, in the structure shown in FIG. 4, the strength of the joint surface between the intermediate layer 22 such as Inconel and the vacuum chamber 20 is not always sufficient, and a baking treatment (accumulation) is caused by the difference in the coefficient of thermal expansion between them. In order to make the inside of the ring 6 an ultra-high vacuum, the whole is heated to a high temperature to evacuate while vacuuming the impurities adhering to the inner surface of the ring 6), and microcracks may be generated at the interface between them. was there.

Further, when the dissimilar material joint 26 as shown in FIG. 5 is used, a stainless material, which is a dissimilar material to the copper material, intervenes in the connecting portion between the vacuum chambers 20 and 20, There is a problem that the electrical characteristics and the thermal characteristics change in that part, and the effectiveness is not always sufficiently satisfactory.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an effective connection structure for connecting vacuum chambers made of a copper material.

[0013]

The invention according to claim 1 is a structure for connecting vacuum chambers made of copper materials, which are used to be connected to each other to form an orbit of charged particles in a particle accelerator. Then, a groove is formed over the entire circumference on the outer peripheral surface of the tip end of the tubular joint body made of a copper material, a ring body made of a stainless material is fitted in the groove, and a flange made of a stainless material is attached to the ring body. By using a fixed joint, the base ends of the joints are welded and joined to the connection ends of both vacuum chambers to be connected, and the vacuum chambers are connected by fastening the flanges of the joints. It is characterized by that.

According to a second aspect of the present invention, a joint provided with an annular rib in place of the flange in the joint is used, and the two vacuum chambers are connected to each other by welding the ribs. It is a feature.

[0015]

According to the present invention, vacuum chambers made of a copper material are connected to each other through a joint. As the joint, a joint body made of the same copper material as the vacuum chamber to be connected is connected to a flange or a ring body. Use the one with ribs attached. The ring body in the joint is formed of a stainless material, and the ring body is attached to the joint body by fitting the ring body into the groove formed at the tip of the joint body by, for example, crimping, press fitting, welding, brazing, or the like. Done in. The flanges and ribs are made of the same stainless steel material as the ring body, and the flanges and ribs are attached to the ring body by fixing them, for example, by welding. Furthermore, the connection of this joint to the vacuum chamber is made by directly welding the base end of the joint body to the tip of the vacuum chamber, but this is welding of copper materials, so to prevent oxidation of the welded portion, for example, Perform in a vacuum atmosphere in a vacuum container.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment. In the first embodiment, a vacuum chamber 20 made of a copper material,
When connecting 20 to each other, those vacuum chambers 2
The vacuum chambers 20 and 20 are connected to each other by joining the joints 30 and 30 to the ends of the vacuum chambers 0 and 20 and fastening the joints 30 and 30 with bolts and nuts.

In the joint 30 of the first embodiment, a groove 32 is formed all around the outer peripheral surface of the tip end of a tubular joint body 31 made of the same copper material as the vacuum chamber 20, and the groove 32 is formed in the groove 32. A ring body 33 made of a stainless material is fitted and a flange 34 also made of a stainless material is welded to the ring body 33.

Ring body 3 with respect to groove 32 of joint body 31
The fitting of No. 3 may be performed by pressure bonding using a hot isostatic pressing method, or may be performed by press fitting or welding or brazing. In addition, the ring body 33
Since the flanges 34 are welded to each other by using stainless steel materials, they can be easily and smoothly performed by a known method. Further, since welding of the joint 30 to the vacuum chamber 20 is welding of copper materials to each other, as described above, it is performed in a vacuum atmosphere, for example, in a vacuum container, and post-treatment is performed on the inner surface of the welded portion if necessary. And good.

In this joint 30, the flange 34 is welded through the ring body 33 fitted to the joint body 31, so that there is a concern in the case of the conventional connection structure shown in FIG. 4, for example. It is possible to sufficiently secure the attachment strength of the flange 34 to the joint body 31 without causing microcracks. Further, the inner surface side of the joint body 31 is entirely made of copper material, and unlike the case where the joint shown in FIG. 5 is used, different materials do not intervene in the joint portion, so electrical characteristics and thermal properties at the joint portion are eliminated. The characteristics do not change.

FIG. 2 shows a second embodiment of the present invention. In the second embodiment, the joint 3 in the first embodiment is used.
The joint 40 is provided with a rib 44 in place of the flange 34 of 0, and the vacuum chambers 20, 20 are connected by welding the ribs 44, 44 of the joints 40, 40 together.

That is, the joint 40 used in the second embodiment is similar to the joint 30 of the first embodiment in that a groove 42 is formed at the tip of a tubular joint body 41 made of a copper material, and the groove 42 is formed in the groove 42. , A ring body 43 made of a stainless material is attached by, for example, pressure bonding, and the ring body 43
An annular rib 44 made of a stainless steel material is welded to the above. Then, in the second embodiment, the ribs 44, 44 of the joints 40, 40 are butted against each other and closely adhered to each other, and the outer peripheral edge portions thereof are welded over the entire circumference, so that the vacuum chambers are connected via the joints 40, 40. Two
0 and 20 are connected together. Since the ribs 44 are made of a stainless steel material, the ribs 44, 44 can be welded to each other without any trouble even in the atmosphere, and the ribs 44 can be welded at a relatively low temperature. Since it largely projects to the outside of the joint body 41, the heat of welding performed at the outer peripheral portion of the rib 44 does not adversely affect the inner surface side of the joint body 41, and the inner surface side of the connection portion may be oxidized. There is no.

According to the structure of the second embodiment, not only the same excellent connection strength as in the first embodiment can be obtained, but also the first embodiment in which the flanges 34 and 34 are fastened with each other by using the bolt and the nut. As compared with the case of the example, the space required for the connecting portion can be reduced, and the step and the gap that are unavoidably generated on the inner surface side of the connecting portion can be further reduced. Further, as shown by a chain line in FIG. 5, the welded portions of the ribs 44, 44, that is, the outer peripheral edge portions of both ribs 44, 44 may be cut off to disconnect them and dismantle the storage ring. After the disassembly, the ribs 44, 44 can be re-welded together to be reconnected.

[0023]

As described above, according to the first aspect of the present invention, a ring body made of a stainless material is fitted in a groove formed at the tip of a joint body made of a copper material, and the ring body is formed. A joint made up of a stainless steel material and a flange made of stainless steel is also used, and the joint is welded to a vacuum chamber made of copper material, and the flanges of these joints are fastened together to connect the two vacuum chambers. As a result, the vacuum chambers made of copper material can be firmly connected to each other, and the electrical characteristics and thermal characteristics may change because different materials do not intervene in the connection part. As a result, it is possible to use a vacuum chamber made of a copper material as the storage ring of the particle accelerator. Further, the invention according to claim 2 uses a joint provided with ribs in place of the flanges, and connects the vacuum chambers by welding the ribs to each other, so that the same effect as the above can be obtained. In addition to this, there is an advantage that the space required for the connecting portion can be further reduced and the step and the gap on the inner surface side of the connecting portion can be made smaller.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of a connection structure of the present invention.

FIG. 2 is a sectional view showing a second embodiment of the connection structure of the present invention.

FIG. 3 is a diagram showing an outline of a small synchrotron.

FIG. 4 is a cross-sectional view showing an example of a conventional connection structure.

FIG. 5 is a cross-sectional view showing another example of a conventional connection structure.

[Explanation of symbols]

 20 vacuum chamber 30 joint 31 joint body 32 groove 33 ring body 34 flange 40 joint 41 joint body 42 groove 43 ring body 44 rib.

Claims (2)

[Claims] 1. A structure for connecting vacuum chambers made of copper material, which are connected to each other and used to form a trajectory of charged particles in a particle accelerator, and a tip of a tubular joint body made of copper material. A groove is formed all around the outer peripheral surface of the portion, a ring body made of a stainless material is fitted in the groove, and a flange made of a stainless material is fixed to the ring body. Welding and joining the base ends of the joints to the connecting ends of the vacuum chambers, and connecting the two vacuum chambers by fastening the flanges of the joints, the vacuum chamber of the particle accelerator characterized in that Connection structure. 2. A structure for connecting vacuum chambers made of copper material, which are used to be connected to each other to form a trajectory of charged particles in a particle accelerator, wherein the tip of a tubular joint body made of copper material. A groove should be formed over the entire outer peripheral surface of the portion, a ring body made of a stainless material should be fitted in the groove, and an annular rib made of a stainless material should be fixed to the ring body for connection. Welding and joining the base ends of the joints to the connecting ends of both vacuum chambers, respectively, the ribs of the joints are brought into close contact with each other, and their outer peripheral edge portions are welded over the entire circumference, so that the two vacuum chambers are joined together. A structure for connecting a vacuum chamber in a particle accelerator, characterized by being connected.