JPH08250298A - Input coupler for superconductor accelerating cavity system - Google Patents

Abstract

PURPOSE: To heighten sealing property by providing a rectangular parallelepiped hollow rectangular part whose one end is opened and a cylindrical flange part which can be connected with a circular wave guide tube and installing a hollow joining part to join the open end of the rectangular part integrally with the flange part. CONSTITUTION: A rectangular part 1a has a rectangular shape, its transverse cross section is square, a hollow part whose one end is opened is formed in the part, and the end part becomes an installation part for a superconductor accelerating hollow system 14. On the other hand, a flange part 1c has a cylindrical shape and is made possible to be connected with a circular wave guide tube. That is, a joining part 1b covers from the open end of the rectangular part 1a to the flange part 1c and forms a hollow part to join both integrally. In other words, of the joining part 1b the transverse cross-section in the edge part in the rectangular part 1a side has a rectangular shape and the transverse cross-section in the edge part in the flange part 1c side has a circular shape. Consequently, the circular flange part can be installed in the tip of an input coupler and a circular wave guide tube can be connected, so that sealing property can be improved and the thickness of the rectangular part can be made thin and the size can be miniaturized and the sealing property can be heightened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an input coupler for a superconducting accelerating cavity system, and is particularly useful when applied to the case where the sealing performance is improved to maintain the vacuum degree of the superconducting accelerating cavity.

[0002]

2. Description of the Related Art FIG. 3 is an explanatory view showing an example of a superconducting accelerated cavity system. The superconducting accelerating cavity system shown in the figure includes a waveguide 12, an input coupler 11, a helium liquefier 20, a high frequency generator 13, a vacuum tank 18, a liquid helium tank 16, a nitrogen shield plate 17, and pipes 15a, 15.
b, 19a, 19b and the superconducting acceleration cavity 14.

Of these, the superconducting accelerating cavity 14 is a hollow member whose left and right ends are open.
It is provided inside the liquid helium tank 16 filled with. The liquid helium tank 16 is provided inside the nitrogen shield plate 17. Further, the nitrogen shield plate 17 is provided inside the vacuum chamber 18.

One end of each of the pipes 15a and 15b is connected to each of the left and right ends of the superconducting acceleration cavity 14, and the liquid helium tank 16, the nitrogen shield plate 17 and the vacuum tank 1 are connected.
8 and the other ends thereof communicate with the outside of the vacuum chamber 18, respectively. The helium liquefying device 20 liquefies helium and circulates the liquefied liquid helium 21 through pipes 19 a and 19 b connected to the liquid helium tank 16.

The input coupler 11 is attached to the right end portion of the superconducting acceleration cavity 14 and has its tip end connected to the lower end portion of the waveguide 12 to superconduct the high frequency wave propagated by the waveguide 12. It is introduced inside the acceleration cavity 14. Further, the waveguide 12 penetrates the liquid helium tank 16, the nitrogen shield plate 17, and the vacuum tank 18, and
The upper end of the high frequency generator 13 is connected to the outside.

According to the superconducting accelerating cavity system described above, the liquid helium 2 circulated by the helium liquefier 20 is circulated.
The charged particle beam 22a flows into the superconducting acceleration cavity 14 cooled by 1 through the pipe 15a,
At the same time, the high frequency generated by the high frequency generator 13 is propagated by the waveguide 12 and then guided by the input coupler 11 into the superconducting acceleration cavity 14. Therefore, the charged particle beam 22a is accelerated in synchronization with the high frequency. The accelerated charged particle beam 22b flows out of the vacuum chamber 18 through the pipe 15b.

The input coupler 11 used in the superconducting accelerating cavity system as described above is an important member that influences the performance of the superconducting accelerating cavity, and has conventionally been classified into a coaxial type coupler and a rectangular waveguide type coupler. There were types. FIG. 4 is an explanatory view showing a rectangular waveguide type coupler and a coaxial type coupler according to the related art.

As shown in FIG. 1 (a), a rectangular waveguide type coupler 31 has a rectangular parallelepiped shape and a rectangular cross section, and has a hollow main body 31a having an open upper end, and is provided at the upper end. It has a square flange portion 31b. According to this rectangular waveguide type coupler 31, a high frequency wave is generated in the hollow portion 31c.
And is guided into the superconducting acceleration cavity 14.

Further, as shown in FIG. 1B, a coaxial type coupler 41 has an outer conductor 41a and an inner conductor 41b which are provided so as to have concentric cross sections, and between the outer conductor 41a and the inner conductor 41b. Has a dielectric 41c provided in. According to the coaxial type coupler 41, the high frequency propagates through the dielectric 41c and is guided into the superconducting acceleration cavity 14.

[0010]

Among the input couplers according to the prior art as described above, the rectangular waveguide type coupler 31 is less likely to cause discharge, and the thickness a ₂ of the main body 31a is reduced within a range where the discharge does not occur. By doing so, it is possible to increase the ratio of the length of the acceleration contribution 14a to the total length of the superconducting acceleration cavity 14 and to shorten the total length, so that the entire superconducting acceleration cavity system can be downsized accordingly. Although it has an advantage, it has a problem that the sealing performance is relatively poor because the flange portion 31b is square. That is, the superconducting accelerating cavity 14 must be kept in a high vacuum (about 1 × 10 ^-10 Torr) for the purpose of maintaining its performance and accelerating the charged particle beam 22a in a stable manner. Therefore, when connecting the rectangular waveguide type coupler 31 and the rectangular waveguide, a sealing member usually made of indium or the like is sandwiched between the flange portion 31b and the flange portion (square) of the rectangular waveguide, Seal between both flanges. However, since it is difficult to apply a uniform load to the seal member at the rectangular flange portion 31b, the collapse of the seal member tends to cause deviation, which easily causes a leak.

Further, the coaxial type coupler 41 includes an outer conductor 41.
Although there is an advantage that the size can be reduced by adjusting the sizes of a and the inner conductor 41b, on the other hand, there is a problem that the structure is complicated and the electric field is likely to be concentrated so that discharge easily occurs. Have.

In view of the above-mentioned prior art, it is an object of the present invention to provide an input coupler for a superconducting accelerating cavity system which can shorten the total length of the superconducting accelerating cavity and has good sealing performance.

[0013]

The structure of the present invention which achieves the above object is a high frequency wave which is attached to a superconducting accelerating cavity and whose tip is connected to a waveguide and propagates in the waveguide. An input coupler of a superconducting accelerating cavity system for introducing into the superconducting accelerating cavity,
It is attached to a superconducting accelerating cavity, and has a rectangular parallelepiped shape and a hollow rectangular portion whose one end is open, a cylindrical flange portion, and an opening end of the rectangular portion that continues to the flange portion to integrally connect the two. And a hollow connecting portion.

[0014]

According to the present invention having the above-mentioned structure, when the flange portion of the input coupler and the flange portion of the waveguide are connected to each other, since both the flange portions are circular, the sealing member sandwiched between the both flanges is provided. As a result, a uniform load is applied from the both flange portions to seal between the both flange portions.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings. The same parts as those in FIG. 3 are designated by the same reference numerals and the duplicate description will be omitted.

FIG. 1 is an explanatory view showing an input coupler of a superconducting accelerating cavity system according to an embodiment of the present invention. As shown in the figure, the input coupler 1 according to the present embodiment is
It has a rectangular portion 1a, a connecting portion 1b, and a flange portion 1c.

Of these, the rectangular portion 1a is a portion having the same shape as the main body 31a of the rectangular waveguide type coupler 31 shown in FIG. 4, that is, a rectangular parallelepiped shape and a rectangular cross section.
It is a hollow portion having one end opened, and is a mounting portion to the superconducting acceleration cavity 14. Also, the thickness a of the rectangular portion 1a
_As with the rectangular waveguide type coupler 31, the value of 1 can be reduced within the range where no discharge occurs.

The flange portion 1c has a cylindrical shape and therefore can be connected to a circular waveguide. FIG. 2 is an explanatory diagram showing an example of a circular waveguide. As shown in the figure, the circular waveguide 42 has a cylindrical main body 42a and circular flange portions 42b and 42c provided at both ends of the main body 42a.

The connecting portion 1b is a hollow portion which continues from the open end of the rectangular portion 1a to the flange portion 1c and integrally connects the both. That is, the connecting portion 1b has a rectangular cross section at the end on the side of the rectangular portion 1a and a circular cross section at the end on the side of the flange portion 1c.

According to the above embodiment, the input coupler 1
Flange portion 1c of the circular waveguide 42 and the flange portion 42b of the circular waveguide 42
When connecting with, both flange portions 1c, 42b have a circular shape, and therefore the sealing members made of indium or the like sandwiched between the both flange portions 1c, 42b are different from the flange portions 1c, 42b.
A uniform load is relatively easily applied from 42b to seal between the flange portions 1c and 42b.

[0021]

As described above in detail with the embodiments, the present invention provides a circular flange portion at the tip of the input coupler and enables connection with a circular waveguide, thus improving the sealing performance. A high vacuum can be maintained inside the superconducting acceleration cavity.

Further, since the rectangular portion, which is a portion to be attached to the superconducting accelerating cavity, has a rectangular cross section, electric field concentration is small and discharge is unlikely to occur. Therefore, since the thickness of the rectangular portion can be reduced within the range where the discharge does not occur, it is possible to increase the ratio of the length of the acceleration contribution portion to the total length of the superconducting acceleration cavity, and to shorten the total length. Therefore, the entire superconducting accelerating cavity system can be downsized accordingly.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an input coupler of a superconducting acceleration cavity system according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a circular waveguide.

FIG. 3 is an explanatory diagram showing an example of a superconducting accelerated cavity system.

FIG. 4 is an explanatory diagram showing an input coupler of a superconducting accelerating cavity system according to the related art.

[Explanation of symbols]

 1, 11 Input coupler 1a Square part 1b Connection part 1c Flange part 12 Waveguide 14 Superconducting acceleration cavity 42 Circular waveguide 42a Main body 42b, 42c Flange part

Claims (1)

[Claims] 1. A superconducting accelerating cavity which is attached to a superconducting accelerating cavity and whose tip is connected to a waveguide to introduce high frequency waves propagating in the waveguide into the superconducting accelerating cavity. An input coupler of the system, which is attached to the superconducting acceleration cavity and has a rectangular parallelepiped hollow rectangular portion with one end open, a cylindrical flange portion, and an opening end of the rectangular portion to the flange portion. An input coupler for a superconducting accelerating cavity system, which further comprises a hollow connecting portion that integrally connects the both.