JPH0850999A - Beam duct - Google Patents

Abstract

PURPOSE:To reduce the number of weld parts so as to improve reliability and also to decrease the thickness of the weld parts the axial direction, so as to suppress an eddy current due to a magnetic field by forming a bellows duct on the end of a vacuum container to in one body with the vacuum container. CONSTITUTION:Reinforcing ribs 8 are mounted by brazing at suitable intervals on the other peripheral surface of a cylindrical vacuum container 7 which has a thin wall and is made of a high electric resistance nonmagnetic material. A connecting flange 1 is welded to one end of the vacuum container 7, bellows 6 for absorbing an axial elongation caused by baking are formed integrally with the other end of the vacuum container 7 at the same time when the vacuum container 7 is formed, and a holding plate 5 for adjustment is mounted by a silver-allow brazing on both boundary surfaces. Thus, troubles resulting from the welding the bellows duct 6 to the vacuum container 7 are overcome, and wall thickness can be made thin by providing the reinforcement ribs 8, therefore the overcurrent generated from the magnetic field of a deflection electromagnet can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a beam duct used in an accelerator such as a synchrotron for accelerating electrons and ions, particularly in a portion where a deflection electromagnet has a high start-up speed.

[0002]

2. Description of the Related Art In an accelerator such as a synchrotron for accelerating electrons or ions, a beam duct is provided at a portion where a rising speed of a deflection electromagnet is high when low incident energy is used with high energy.

Therefore, in the beam duct, a large eddy current is generated due to the magnetic flux from the deflection electromagnet, and the beam is bent by the magnetic field formed by this eddy current and deviates from the target trajectory.

Therefore, as a conventional beam duct, in order to suppress eddy current, a bellows having a high resistance and a thin wall structure or a connection bellows having a welded structure are formed.

FIG. 4 shows the structure of the molded bellows 6, and the connection flanges 1 are attached to both ends thereof.
Further, FIG. 5 shows a structure of the welded bellows 10, and connection flanges 1 are attached to both ends thereof.

However, it is difficult to manufacture the above-described beam duct using the molded bellows or the welded bellows when a long distance is required. Therefore, conventionally, as shown in FIG. 6, a connecting flange 1 is attached by welding or the like to one end of a thin vacuum container 7 having brazing ribs 8 provided at appropriate intervals on the outer peripheral surface thereof. One end of the bellows duct 6 is joined by welding to the other end of the vacuum container 7 via a holding plate 5 for adjustment, and the other end is attached to the connecting flange 1 by welding.

[0007]

Generally, whether the beam duct is thick or thin, the beam duct is expanded and contracted in the beam axial direction during the entire assembly. In addition, baking is performed to increase the degree of vacuum, but at this time there is expansion and contraction due to the heat generated in the duct.

Therefore, the expansion and contraction of the duct is absorbed by the bellows 6 joined to the end of the duct, so that the external force acting on the connecting flange side is reduced. However, in the beam duct having such a structure, there are many welded portions for connecting the adjusting presser plate 5 for adjusting the expansion and contraction, the vacuum container 7, the connecting flange and the like to the bellows portion, so that a welding defect is likely to occur. There are many.

When the beam energy is large and the eddy current generated in the beam duct is large, the vacuum container 7
Although the adjusting presser plate 5 is attached to one end or both ends, from the viewpoint of suppressing the generation of the eddy current, there is a problem in the method of attaching and reinforcing the adjusting presser plate.

As described above, the large number of welding points and the provision of the adjusting pressing plate pose various problems in improving the quality of the beam duct. The present invention has been made to solve the above problems, and an object of the present invention is to provide a beam duct in which a vacuum container can be easily incorporated and baking can be easily performed to improve reliability.

[0011]

In order to achieve the above object, the present invention constitutes a beam duct by the following means. The invention corresponding to claim 1 is a beam duct in which reinforcing ribs are attached to the outer surface of a thin-walled cylindrical vacuum container through which an electron or ion beam is passed, and at least one end of the vacuum container is adjusted in length. A bellows duct for use is provided, and this bellows duct is formed integrally with the vacuum container.

According to a second aspect of the present invention, a length adjusting holding plate is attached to the boundary surface between the vacuum container and the bellows duct with a silver braze. The invention corresponding to claim 3 is a beam duct in which reinforcing ribs are attached to an outer surface of a thin-walled cylindrical vacuum container through which an electron or ion beam is passed.
A bellows duct for length adjustment is provided at at least one end of the vacuum container, the bellows duct is formed integrally with the vacuum container, and a ring-shaped insulator is connected to the end of the bellows duct inside the connection flange. Install and install.

[0013]

In the beam duct of the invention corresponding to the above claims 1 and 2, the thin walled vacuum container and the bellows are brazed with reinforcing ribs on the outer peripheral surface at appropriate intervals. Since it is processed at the same time and integrally molded, the same function as in the past is maintained and the number of welds for joining is reduced,
It is possible to reduce defects due to welding defects,
The reliability can be increased.

Further, since the adjusting pressing plate is brazed only for the purpose of adjusting the length of the bellows, the thickness in the axial direction can be reduced and the generation of eddy current due to the influence of the magnetic field of the deflection electromagnet can be suppressed. It will be possible.

In the beam duct of the invention corresponding to the third aspect, the same operational effect as described above can be obtained, and the ring-shaped insulator joined to the end of the bellows duct is connected and connected to the flange. Since it is provided inside, the eddy current due to the influence of the magnetic field of the deflection electromagnet, the image current generated by the beam, and the like can be effectively cut off.

In addition, in the beam duct of the invention according to claims 1 to 3, since the inner surface area of the vacuum container is small, it is possible to obtain advantages such as easy vacuum evacuation.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a first embodiment of a beam duct according to the present invention. In FIG. 1, 7 is a thin wall (for example, 0.2 to 0.5 mm) having a high electric resistance and made of a non-magnetic material.
A cylindrical vacuum container having a wall thickness), and reinforcing ribs 8 are attached by brazing to the outer peripheral surface of the vacuum container 7 at appropriate intervals so as to withstand the pressure difference between the inside and the outside. In this case, a ring-shaped bulging portion for fixing the reinforcing rib 8 is formed on the outer peripheral surface of the vacuum container 7.

A connecting flange 1 is attached to one end of the vacuum container 7 by welding, and a bellows duct 6 for absorbing axial extension due to baking is attached to the other end.
Is integrally molded, and the adjusting holding plate 5 is attached to the boundary surface between the vacuum container 7 and the bellows duct 6.

In this case, the bellows duct 6 provided at the end of the vacuum container 7 is formed by simultaneously processing the vacuum container 7 when forming the vacuum container 7. Further, the pressing plate 5 for adjusting the expansion and contraction of the bellows duct 6 is also attached at the same time when the vacuum container 7 is formed by using silver brazing.

On the other hand, the connection flange 1 attached to the end of the bellows duct 6 has an annular groove 1a formed on the bellows duct side of the hole at the center as shown in FIG. 2, and the annular groove 1a has a ring shape. The ceramic 3 is inserted, the sealing metal 2 is inserted from both axial ends of the ceramic 3 to the inner peripheral surface of the hole, and the ceramic retainer 11 is provided on the opening side of the annular groove 1a. Annular groove 1a
A disk-shaped insulating material 4 is inserted with the sealing metal 2 extending toward the bellows duct side as a central axis. Then, the end portion of the bellows duct 6 is attached to the insulating material 4 via the metallic joint 9.

In this case, it is possible to weld the bellows duct 6 and the joint 5 and simultaneously form the joint between the ceramic 3 and the ceramic retainer 11 and the sealing metal 2 and braze them. Therefore, by mounting the bellows duct 6 on the connecting flange 1 in this manner, the bellows duct 6 is coupled to the connecting flange 1 in an axially insulated state.

In the beam duct having such a structure, the thin-walled vacuum container 7 and the bellows duct 6 which are brazed with reinforcing ribs 8 at appropriate intervals on the outer peripheral surface are simultaneously processed to be integrated. Since it is formed in the above-described manner, it is possible to prevent problems that would occur when the vacuum container 7 and the bellows duct 6 are joined by welding as in the conventional case.

Therefore, it can be applied to a large or small particle accelerating ring using a vacuum container. In particular, in the case of downsizing, since the polarities of the bending electromagnets are reduced, a design matching the curvature of the vacuum container 7 is required. However, a small ring shape for fixing the reinforcing rib 8 attached to the vacuum container 7 is required. Since there is a bulge, the bending can be performed freely.

Further, the pressing plate 5 for adjusting the expansion and contraction of the bellows duct 6 at the time of forming the vacuum container 7 can be simultaneously silver brazed, and when the bellows duct 6 is attached to the connection flange 1 via the insulating material 4, the connection flange The sealing metal 2 is inserted into both end faces of the ceramic 3 axially pressed by the ceramic presser 11 in the annular groove 1a formed in the axial direction 1 and joined by brazing to provide axial insulation. Therefore, it is possible to cut off the eddy current generated in the connection portion between the bellows duct 6 and the connection flange 1 and the current generated by the beam when the magnetic field is raised by the deflection electromagnet.

Furthermore, since the ceramic 3 is provided inside the connection flange 1, welding such as vacuum sealing is facilitated. FIG. 3 is a sectional view showing a second embodiment of the beam duct according to the present invention. Here, the points different from FIG. 1 will be described.

In the second embodiment, as shown in FIG. 3, the bellows duct 6 formed integrally with the vacuum container 7 is formed.
Of the ring-shaped ceramic, the ends of which are joined to the connection flange 1 by welding, and both ends in the axial direction of the annular hole 1b provided in the outer periphery of the central hole of the connection flange 1 are brazed and held by the sealing metal 2. 3 is provided with insulation in the radial direction.

Even with such a structure, the same operational effect as that of the first embodiment described above can be obtained. In addition, in the said 1st Example and 2nd Example, although the case where the bellows duct was integrally molded at one end side of the vacuum container 7 was described, the bellows duct is integrally molded at both end sides of the vacuum container. You may do it.

[0028]

As described above, according to the present invention, it is possible to provide a beam duct in which a vacuum container can be easily incorporated and baking can be easily performed and reliability can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of a beam duct according to the present invention.

FIG. 2 is an enlarged cross-sectional view showing a joint portion between a connection flange portion and a beam duct in the embodiment.

FIG. 3 is a cross-sectional view of a beam duct showing a second embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a beam duct using a conventional bellows duct.

FIG. 5 is a cross-sectional view showing a beam duct using a conventional welded bellows duct.

FIG. 6 is a sectional view showing a beam duct in which a conventional vacuum container and a bellows duct are joined.

[Explanation of symbols]

1 ... Connection flange, 2 ... Sealing metal, 3 ... Ceramic, 4 ... Insulation material, 5 ... Adjusting holding plate, 6 ... Bellows duct, 7 ... Vacuum container, 8 ... Reinforcing rib, 9: Joint.

Claims (3)

[Claims] 1. A beam duct in which reinforcing ribs are attached to an outer peripheral surface of a thin-walled tubular vacuum container through which an electron or ion beam is passed, and a bellows duct for length adjustment is provided at least at one end of the vacuum container. The beam duct is characterized in that the bellows duct is formed integrally with a vacuum container. 2. The beam duct according to claim 1, wherein
A beam duct characterized in that a pressing plate for length adjustment is attached to the boundary surface between the vacuum container and the bellows duct by means of silver brazing. 3. A beam duct in which reinforcing ribs are attached to the outer surface of a thin-walled tubular vacuum container through which an electron or ion beam is passed, a bellows duct for length adjustment being provided at least at one end of the vacuum container. A beam duct, wherein the bellows duct is formed integrally with the vacuum container, and a ring-shaped insulator is provided inside the connection flange at the end of the bellows duct.