High Frequency Input Coupler

Abstract

To provide a high-frequency input coupler that can prevent a gap from being generated between a dielectric substrate and a high-frequency window structure.SOLUTION: The high-frequency input coupler is installed between a waveguide and an acceleration cavity and inputs a high-frequency wave from the waveguide to the acceleration cavity. The high-frequency input coupler includes an inner conductor, an outer conductor provided around the periphery of the inner conductor, a high-frequency transmission window structure having a high-frequency transmission window, and a dielectric substrate provided on a high-frequency input side of the high-frequency transmission window. The dielectric substrate is fixed to the high-frequency transmission window structure by brazing.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] SUMMARY OF THE DISCLOSURE The present invention relates to a high frequency input coupler. [Background technology]

[0002] RF input couplers are used in charged particle (electron, ion, proton) accelerators to input RF (microwave) waves emitted from a RF amplifier such as a klystron into an accelerating cavity.

[0003] When injecting high frequency (microwave) waves into an accelerating cavity, a high frequency input coupler with a structure that can provide good coupling to the accelerating cavity is required. The high frequency input coupler is mainly composed of a high frequency transparent window structure with a high frequency transparent window, an outer conductor, and an inner conductor (antenna), and the outer conductor and the inner conductor form a coaxial structure. In such a high-frequency input coupler, a dielectric substrate may be disposed on the high-frequency input side of a high-frequency transparent window structure, and a waveguide having a coaxial-waveguide conversion structure for converting a high-frequency wave transmitted from a high-frequency source is attached to the high-frequency transparent window structure on the high-frequency inlet side. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 02-295023 Summary of the Invention [Problem to be solved by the invention]

[0005] Conventionally, the dielectric substrate is fixed by being sandwiched between the waveguide side end of the inner sleeve (inner conductor) of the high frequency transparent window structure and the other end of the waveguide side inner conductor, one end of which is fixed to the coaxial waveguide conversion part (doorknob) with a bolt. However, when the dielectric substrate is sandwiched and fixed between the bolted waveguide side inner conductor and the inner sleeve (inner conductor), the bolt may become loose, for example, after long-term use. In that case, a gap may be generated in the sandwiched part of the dielectric substrate, and discharge may occur when high frequency is input, causing operation problems. In addition, the same problem may occur when a gap is generated between the dielectric substrate and the sandwiched part of the dielectric substrate, even if the bolt is not loosened.

[0006] An object of this embodiment is to provide a high-frequency input coupler that can prevent a gap from occurring between the dielectric substrate and the high-frequency window structure. [Means for solving the problem]

[0007] One embodiment is a radio-frequency input coupler that is provided between a waveguide and an accelerating cavity and inputs radio frequency from the waveguide to the accelerating cavity, the radio-frequency input coupler comprising an inner conductor, an outer conductor provided on the outer periphery of the inner conductor, a radio-frequency transparent window structure having a radio-frequency transparent window, and a dielectric substrate provided on the radio-frequency input side of the radio-frequency transparent window, the dielectric substrate being fixed to the radio-frequency transparent window structure by brazing. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a vertical cross-sectional view showing a state in which a high-frequency input coupler according to a first embodiment is provided between a waveguide and an accelerating cavity. [Diagram 2] FIG. 2 is a vertical cross-sectional view showing a state in which a high-frequency input coupler according to a second embodiment is provided between a waveguide and an accelerating cavity. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] An embodiment will be described in detail below with reference to the drawings. In addition, in order to clarify the description, the width, thickness, shape, etc. of each part may be shown in a schematic manner compared to the actual embodiment, but this is merely an example and does not limit the interpretation of the present invention. In this specification and each drawing, components that perform the same or similar functions as those described above with respect to the previous drawings are given the same reference numerals, and duplicate detailed descriptions may be omitted as appropriate.

[0010] The first embodiment will be described with reference to FIG. As shown in FIG. 1, a high-frequency input coupler 1 according to the first embodiment is provided between a waveguide 3 and an accelerating cavity 5 , and inputs a high-frequency wave from the waveguide 3 to the accelerating cavity 5 . This high-frequency input coupler 1 comprises an inner conductor 7, an outer conductor 9 provided around the outer periphery of the inner conductor 7, a high-frequency transparent window structure 13 having a high-frequency transparent window 11, and a dielectric substrate 14 provided on the high-frequency input side of the high-frequency transparent window 11. The waveguide 3 is assembled mainly by welding. In addition, a coaxial-waveguide converter 15 called a doorknob is connected to the waveguide 3 by welding.

[0011] The inner conductor 7 is provided so as to penetrate the high frequency transparent window structure 13, and a waveguide side inner conductor 8 continuous with the inner conductor 7 is provided in the coaxial-waveguide conversion section 15 of the waveguide 3. One end 8a of the waveguide side inner conductor 8 is fixed to the coaxial-waveguide conversion section 15 by a bolt 18 via a waveguide side inner conductor presser 17. One end of the inner conductor 7 has an antenna portion 7 a that is disposed so as to protrude into the accelerating cavity 5 .

[0012] The high frequency input side end 7b of the inner conductor 7 and the other end (the end on the high frequency transmitting window structure 13 side) 8b of the waveguide side inner conductor 8 abut against each other and are continuous with each other.

[0013] The outer conductor 9 is provided coaxially with the inner conductor 7, and its end on the acceleration cavity 5 side is connected to the acceleration cavity 5 via a vacuum side flange 21, while its inner peripheral side is fixed to an outer sleeve 23 (described later) of the radio frequency transparent window structure 13. The inner conductor 7, the vacuum side flange 21 and the outer conductor 9 are assembled by brazing, welding or the like after assembling the radio frequency transparent window structure 13 (described later) by brazing.

[0014] The radio frequency transparent window structure 13 includes a radio frequency transparent window 11 that maintains airtightness and transmits radio frequency, and an outer sleeve 23 and an inner sleeve 25 that form a transmission path. The radio frequency transparent window 11 is formed in an annular shape, and the inner sleeve 25 is inserted into the annular shape to separate the vacuum side and the atmosphere side between the inner sleeve 25 and the outer sleeve 23. The radio frequency transparent window 11 is made of a ceramic such as alumina.

[0015] The outer sleeve 23 and the inner sleeve 25 are made of copper. The inner sleeve 25 is continuous with the inner conductor 7, and in this embodiment, the inner sleeve 25 and the inner conductor 7 are made of the same material.

[0016] The dielectric substrate 14 is provided in the radio frequency transmitting window structure 13 on the radio frequency input side of the radio frequency transmitting window 11. The dielectric substrate 14 is fixed to the radio frequency transmitting window structure 13 by brazing, as described later. The dielectric substrate 14 is made of alumina and is formed in a ring shape.

[0017] The dielectric substrate 14 has an inner peripheral edge 14a brazed to an inner sleeve 25 of the radio frequency transmitting window structure 13 and an outer peripheral edge 14b brazed to an outer sleeve 23 of the radio frequency transmitting window structure 13. Each brazing is performed using a first brazing material 27a arranged between the inner peripheral edge 14a of the dielectric substrate 14 and the outer peripheral surface of the inner sleeve 25, and a second brazing material 27b arranged between the outer peripheral edge 14b of the dielectric substrate 14 and the inner peripheral surface of the outer sleeve 23. 1, the dashed lines indicate the arrangement of the brazing filler metals 27a and 27b. The first brazing filler metal 27a and the second brazing filler metal 27b are ribbon-shaped (thin strip-shaped) brazing filler metals.

[0018] In the waveguide 3, a radio frequency transparent window structure connecting portion 29 is provided at a position facing the coaxial-waveguide conversion portion 15. In the radio frequency transparent window structure connecting part 29, an atmosphere side flange 31 brazed to the outer sleeve 23 of the radio frequency transparent window structure 13 is sandwiched between a fastened part 29a and a fastening part 29b of the radio frequency transparent window structure connecting part 29, and the fastened part 29a and the fastening part 29b are fixed with a bolt 32. The atmosphere side flange 31 also functions as a flange for centering the radio frequency transparent window structure 13.

[0019] The high-frequency input coupler 1 according to the first embodiment is attached by fixing the waveguide-side inner conductor 8 to the coaxial-waveguide conversion portion 15 via the waveguide-side inner conductor retainer 17 with bolts 18. It is even more preferable to further fix the inner conductor end portion 7b with a bolt. Meanwhile, the dielectric substrate 14 is fixed between the outer sleeve 23 and the inner sleeve 25 of the radio frequency transparent window structure 13 by brazing, and at the radio frequency transparent window structure connecting portion 29, the radio frequency transparent window structure 13 with the dielectric substrate 14 fixed thereto is centered with the atmosphere side flange 31 while the bolts 32 are tightened to fasten the fastened portion 29a to the fastening portion 29b.

[0020] The effects of this embodiment will be described. Since the dielectric substrate 14 is fixed to the radio frequency transmitting window structure 13 by brazing, it is possible to prevent a gap from being formed between the dielectric substrate 14 and the radio frequency transmitting window structure 13. That is, as in the conventional technology, when the dielectric substrate 14 is fixed by being sandwiched between the radio frequency input side end 7b of the inner sleeve (inner conductor) 25 of the radio frequency transmitting window structure 13 and the other end 8b of the waveguide side inner conductor 8, one end of which is fixed to the coaxial waveguide conversion section (doorknob) by a bolt 18, there was a risk of a gap being formed between the dielectric substrate 14 and the sandwiched portion. However, in this embodiment, since the dielectric substrate 14 is fixed to the radio frequency transmitting window structure 13 by brazing, it is possible to prevent a gap from being formed between the dielectric substrate 14 and the radio frequency transmitting window structure 13.

[0021] Furthermore, the annular dielectric substrate 14 has its inner peripheral edge 14a brazed to the inner sleeve 25 of the radio frequency transparent window structure 13 and its outer peripheral edge 14b brazed to the outer sleeve 23 of the radio frequency transparent window structure 13, thereby preventing gaps from occurring at both the inner peripheral edge 14a and the outer peripheral edge 14b of the dielectric substrate 14 and enabling the dielectric substrate 14 to be firmly fixed. The dielectric substrate 14 is brazed with a first brazing material 27a arranged between its inner peripheral edge 14a and the outer peripheral surface of the inner sleeve 25, and with a second brazing material 27b arranged between its outer peripheral edge 14b and the inner peripheral surface of the outer sleeve 23, making it easy to manufacture. The first brazing filler metal 27a and the second brazing filler metal 27b are ribbon-shaped brazing filler metals and are therefore easy to arrange.

[0022] Other embodiments will be described below. In the embodiments described below, the parts that have the same effect as the first embodiment described above will be given the same reference numerals, and detailed descriptions of those parts will be omitted. The second embodiment will be described with reference to FIG. In the second embodiment, the method of fixing the dielectric substrate 14 to the high frequency transmitting window structure 13 is different. An inner peripheral edge receiving portion 25a is formed on the inner sleeve 25 of the high frequency transmitting window structure 13 to receive the inner peripheral edge 14a of the dielectric substrate 14. The inner peripheral edge receiving portion 25a is a recessed step portion. The inner peripheral edge 14a of the dielectric substrate 14 is brazed to the inner sleeve 25 by a third brazing material 27c placed on the inner peripheral edge receiving portion 25a. Further, an outer peripheral edge receiving portion 23a for receiving the outer peripheral edge 14b of the dielectric substrate 14 is formed on the outer sleeve 23 of the high frequency transmitting window structure 13. The outer peripheral edge receiving portion 23a is a recessed step portion. The outer periphery 14b of the dielectric substrate 14 is brazed to the inner sleeve 25 by means of a fourth brazing material 27d placed on the outer periphery receiving portion 23a.

[0023] An inner peripheral presser 33 that presses from the high frequency input side is provided on the inner peripheral edge of the dielectric substrate 14. Similarly, an outer peripheral presser 35 that presses from the high frequency input side is provided on the outer peripheral edge of the dielectric substrate 14. The inner peripheral presser 33 has its high frequency input side abutted against the other end 8b of the waveguide side inner conductor 8, and the outer peripheral presser 35 has its high frequency input side abutted against the fastened portion (waveguide side member) 29a. The inner peripheral holder 33 and the outer peripheral holder 35 each have an L-shaped cross section, and are disposed so as to fit into the edge of the corresponding dielectric substrate 14 from the high frequency input side. The inner peripheral presser 33 is brazed to the inner peripheral edge 14a of the dielectric substrate 14 by a fifth brazing material 27e placed on the high frequency input side. The outer periphery presser 35 is brazed to the outer periphery 14b of the dielectric substrate 14 by a sixth brazing material 27f placed on the high frequency input side.

[0024] The high-frequency input coupler 1 according to the second embodiment is attached by fixing the waveguide-side inner conductor 8 to the coaxial-waveguide conversion portion 15 via the waveguide-side inner conductor holder 18 with bolts 18 . On the other hand, the dielectric substrate 14, the inner peripheral holder 33 and the outer peripheral holder 35 are fixed to the radio frequency transparent window structure 13 by brazing between the outer sleeve 23 and the inner sleeve 25, and the high frequency transparent window structure 13 to which the dielectric substrate 14, the inner peripheral holder 33 and the outer peripheral holder 35 are fixed is centered with the atmosphere side flange 31 at the radio frequency transparent window structure connecting portion 29, and the bolts 32 are tightened to fasten the fastened portion 29a and the fastening portion 29b. As a result, the outer peripheral holder 35 brazed to the dielectric substrate 14 is pressed against the fastened portion 29 and fixed to the outer peripheral side of the dielectric substrate 14. On the other hand, an inner peripheral presser 33 brazed to the inner peripheral edge 14a of the dielectric substrate 14 is pressed against the other end 8b of the waveguide side inner conductor 8 and fixed.

[0025] The effects of the second embodiment will be described. According to the second embodiment, similarly to the first embodiment, the dielectric substrate 14 is fixed to the radio frequency transmitting window structure 13 by brazing, thereby preventing the formation of a gap between the dielectric substrate 14 and the radio frequency transmitting window structure 13. The third brazing material 27c used to braze the dielectric substrate 14 is placed on the stepped inner peripheral edge receiving portion 25a formed on the inner sleeve 25, and the fourth brazing material 27d can be placed on the stepped outer peripheral edge receiving portion 23a formed on the outer sleeve 23, making it easy to install the third brazing material 27c and the fourth brazing material 27d when brazing. The inner peripheral pressure member 33 is brazed using the fifth brazing material 27e placed on the high frequency input side of the inner peripheral edge 14a of the dielectric substrate 14, and the outer peripheral pressure member 35 is brazed using the sixth brazing material 27f placed on the high frequency input side of the outer peripheral edge 14b of the dielectric substrate 14, so that the brazing materials 27e, 27f can be easily positioned when brazing.

[0026] The above-described embodiment is presented as an example and is not intended to limit the scope of the invention. These novel embodiments can be implemented 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 in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0027] 1...high frequency input coupler, 3...waveguide, 5...accelerating cavity, 7...inner conductor, 9...outer conductor, 11...high frequency transparent window, 13...high frequency transparent window structure, 14...dielectric substrate, 14a...inner peripheral edge, 14b...outer peripheral edge, 23...outer sleeve, 23a...outer peripheral edge support portion, 25...inner sleeve, 25a...inner peripheral edge support portion, 27a...first soldering material, 27b...second soldering material, 27c...third soldering material, 27d...fourth soldering material, 27e...fifth soldering material, 27f...sixth soldering material, 33...inner peripheral clamp, 35...outer peripheral clamp.

Claims

1. A radio frequency input coupler is provided between a waveguide and an accelerating cavity for inputting radio frequency waves from the waveguide to the accelerating cavity, the radio frequency input coupler comprising: an inner conductor; an outer conductor provided on an outer periphery of the inner conductor; a radio frequency transparent window structure having a radio frequency transparent window; and a dielectric substrate provided on a radio frequency input side of the radio frequency transparent window; the dielectric substrate has an annular shape, an inner peripheral edge of the dielectric substrate being disposed in an inner sleeve of the radio frequency transmitting window structure, and an outer peripheral edge of the dielectric substrate being disposed in an outer sleeve of the radio frequency transmitting window structure; A high-frequency input coupler in which the inner sleeve is formed with a stepped inner edge support portion that receives the inner edge of the dielectric substrate, and the outer sleeve is formed with a stepped outer edge support portion that receives the outer edge of the dielectric substrate, and the dielectric substrate is brazed to the inner sleeve and outer sleeve with brazing material placed on the inner edge support portion and the outer edge support portion.

2. an inner peripheral holder that presses the inner peripheral edge of the dielectric substrate from the high frequency input side, and an outer peripheral holder that presses the outer peripheral edge of the dielectric substrate from the high frequency input side, the inner peripheral holder abutting the high frequency input side surface against a waveguide side inner conductor, and the outer peripheral holder abutting the high frequency input side surface against a waveguide side member, 2. The high-frequency input coupler according to claim 1, wherein the inner peripheral clamp and the outer peripheral clamp are brazed to the dielectric substrate by brazing material arranged on the high-frequency input side at positions corresponding to the inner peripheral clamp and the outer peripheral clamp.

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