High-frequency transparent window structure

Abstract

To provide a high-frequency transparent window structure capable of suppressing discharge generation.SOLUTION: A high-frequency transparent window structure 12 includes an outer conductor 21, an inner conductor 22 positioned inside the outer conductor 21 and forming a coaxial line 20 that transmits high-frequency waves together with the outer conductor 21, and a high-frequency transparent window 25 fixed between the outer conductor 21 and the inner conductor 22, separating the coaxial line 20 into a vacuum side 23 and an atmospheric side 24. The coaxial line 20 includes a discharge generation portion 26 caused by discharges generated due to high-frequency transmission, and an electrical insulating material 27 is provided covering the discharge generation portion 26.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION An embodiment of the present invention relates to a radio frequency transparent window assembly. [Background technology]

[0002] A high-frequency airtight window structure separates, for example, a coaxial line that transmits high frequencies into a vacuum side and an atmospheric side by a high-frequency transparent window, and is used in output lines for klystrons and couplers for linear accelerators.

[0003] Because radio frequency transparent window structures have a complex structure and must be airtight, they are manufactured using welding, brazing, etc. During manufacturing, leak tests can be conducted to confirm vacuum tightness, but because they cannot transmit radio frequency waves, it is difficult to detect defects in areas unrelated to airtightness.

[0004] Therefore, when high-power radio frequency waves are transmitted through the radio frequency transmitting window structure after completion of a product such as a klystron or coupler, one of the main problems that can occur is that a discharge occurs in the coaxial line. If a discharge occurs, performance may be reduced, and since the discharge generating part where a discharge has occurred once can become the starting point of a new discharge, it is desirable to repair it to suppress the discharge, but it may be difficult to disassemble and reassemble the coaxial radio frequency transmitting window structure that is manufactured using welding or brazing. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-257501 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a radio frequency transparent window structure capable of suppressing the occurrence of discharge. [Means for solving the problem]

[0007] The radio-frequency transmitting structure of this embodiment includes an outer conductor, an inner conductor located inside the outer conductor and constituting a coaxial line for transmitting radio frequency waves together with the outer conductor, and a radio-frequency transmitting window fixed between the outer conductor and the inner conductor and separating the coaxial line into a vacuum side and an atmosphere side. The inner conductor has a discharge generating portion that generates a discharge due to the transmission of radio frequency waves, and an electrical insulating material is provided to cover the discharge generating portion. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a configuration diagram of a high-frequency amplifier that uses a high-frequency transparent window structure according to an embodiment. [Figure 2] 1A and 1B show the same high frequency transmitting window structure, in which FIG. 1A is a cross-sectional view of a normal high frequency transmitting window structure, and FIG. 1B is a cross-sectional view of a high frequency transmitting window structure in which a discharge generating portion is present. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment will be described below with reference to the drawings.

[0010] Fig. 1 shows a high-frequency amplifier 10. The high-frequency amplifier 10 is, for example, a vacuum tube such as a klystron. The high-frequency amplifier 10 includes a high-frequency amplifier main body 11 that amplifies high-frequency waves, and a high-frequency transparent window structure 12 that is connected to the output section of the high-frequency amplifier main body 11 and outputs the amplified high-power high-frequency waves to the outside.

[0011] 2(a) and (b) show the radio-frequency-transmitting window structure 12. The radio-frequency-transmitting window structure 12 includes an outer conductor (outer sleeve) 21 that forms a coaxial line 20, which is a radio-frequency transmission line, an inner conductor (inner sleeve) 22 that is located inside the outer conductor 21, and a radio-frequency-transmitting window 25 that is fixed between the outer conductor 21 and the inner conductor 22 and separates the coaxial line 20 into a vacuum side 23 and an atmosphere side 24.

[0012] The outer conductor 21 is made of a metal such as copper and is formed in a cylindrical shape. The inner conductor 22 is made of a metal such as copper and is formed in a cylindrical shape. The outer conductor 21 and the inner conductor 22 are arranged coaxially, and a coaxial line 20 for transmitting high frequency waves is formed between the outer conductor 21 and the inner conductor 22.

[0013] The radio frequency transparent window 25 is made of a dielectric ceramic such as alumina and is formed in the shape of a circular disk. The outer peripheral surface of the radio frequency transparent window 25 is airtightly joined to the inner peripheral surface of the outer conductor 21, for example, by soldering or welding. The radio frequency transparent window 25 separates the coaxial line 20 into a vacuum side 23 on the side of the radio frequency amplifier main body 11 and an atmosphere side 24 opposite the radio frequency amplifier main body 11, and allows radio frequency waves output from the radio frequency amplifier main body 11 to pass from the vacuum side 23 to the atmosphere side 24 while maintaining airtightness between the vacuum side 23 and the atmosphere side 24.

[0014] The high-frequency transmitting window structure 12 shown in FIG. 2( a ) shows a normal state in which no discharge occurs when a high-frequency wave is transmitted through the coaxial line 20 .

[0015] 2(b) shows the case where a discharge occurs in the radio-frequency transmitting window structure 12 when a high frequency is transmitted through the coaxial line 20. The discharge occurs on the atmosphere side 24 of the radio-frequency transmitting window 25, on the surface of the inner conductor 22 a short distance from the radio-frequency transmitting window 25, and a discharge generation part 26 remains as a discharge mark on the surface of the inner conductor 22. If a discharge generation part 26 exists on the surface of the inner conductor 22, it becomes easier for further discharges to occur, with the discharge generation part 26 serving as the starting point.

[0016] Therefore, in the radio frequency transparent window structure 12 of this embodiment, an electrical insulating material 27 is provided on the surface of the inner conductor 22 to cover the discharge generating portion 26. The electrical insulating material 27 can be made of an electrically insulating material such as polytetrafluoroethylene such as Teflon (registered trademark), polyimide film such as Kapton (registered trademark), or PEEK resin, and is provided so as to cover the discharge generating portion 26 by means of coating or the like.

[0017] If the discharge generating portion 26 is also present on the surface (inner surface) of the outer conductor 21 , the discharge generating portion 26 of the outer conductor 21 may be covered with an electrical insulating material 27 .

[0018] In this way, in the radio frequency transparent window structure 12 of this embodiment, by covering the discharge generating portion 26 with the electrical insulating material 27, discharge in the discharge generating portion 26 can be prevented.

[0019] Discharge is suppressed by covering the discharge generating portion 26 caused by discharge on the surface of the inner conductor 22 on the atmospheric side 24 with an electrical insulating material 27, so discharge can be suppressed more easily than when repairs are performed that require disassembly of the high-frequency transparent window structure 12.

[0020] The high frequency transparent window structure 12 can be used not only for the output line of the klystron but also for a coupler of a linear accelerator.

[0021] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0022] 12 High frequency transparent window structure 20 coaxial line 21 outer conductor 22 Inner conductor 23 Vacuum side 24 Atmospheric side 25 High frequency transparent window 26 Discharge generating unit 27 Electrical insulation materials

Claims

1. A radio frequency transparent structure comprising: an outer conductor; an inner conductor located inside the outer conductor and constituting a coaxial line for transmitting radio frequency waves together with the outer conductor; and a radio frequency transparent window fixed between the outer conductor and the inner conductor and separating the coaxial line into a vacuum side and an atmosphere side, The inner conductor has a discharge generating portion where discharge occurs due to the transmission of high frequency waves, and an electrical insulating material is provided to cover this discharge generating portion. A high frequency transparent window structure.

2. The electrical insulating material covers the discharge generating portion on the atmosphere side.

2. The high frequency transparent window structure according to claim 1.

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