JPH0438448Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention relates to an improvement in the output section of a microwave electron tube such as a klystron.

[Technical background of the invention and its problems]

The structure of the output section of a microwave electron tube such as a klystron is such that a coaxial line is connected to the output cavity, and a rectangular waveguide is coupled to the tip of the coaxial line. A vacuum-tight window made of ceramic dielectric is provided in a part of the waveguide. Alternatively, a dielectric airtight wall may be provided in the middle of the coaxial line section. However, these methods have the disadvantage that the inside of the waveguide must be evacuated, and the coupling characteristics between the coaxial line and the waveguide cannot be adjusted after the tube is evacuated. Furthermore, if the output waveguide is formed integrally with the tube body, for example, the output coupling structure to an external device is restricted.

[Purpose of invention]

This idea eliminates the above-mentioned disadvantages, keeps the vacuum area of the output section to the minimum necessary, and
Any thing can be connected as an output waveguide,
Moreover, the present invention provides a structure for the output section of a microwave electron tube that allows the coupling characteristics between the coaxial line and the output waveguide to be easily adjusted as desired after the tube body is evacuated, and that is easy to assemble.

[Summary of the idea]

This invention is based on a microcomputer comprising an output cavity, such as a klystron, which is coupled to the output cavity and whose interior is kept in a vacuum, and a coaxial line section having an inner conductor and an outer conductor coupled to the output cavity. In the output section of the wave electron tube, one end of the inner and outer conductors of the coaxial line section are vacuum-tightly joined to the output cavity wall, and a dielectric airtight ring is provided between the outer circumferential wall of the inner conductor and the inner circumferential wall of the outer conductor. is vacuum-tightly sealed, and the tip of the inner conductor is split on the part at the outer end of the dielectric airtight ring's sealing position, which can be installed or replaced after the tube body is evacuated. The output section is characterized in that the output section is connected to each other.

This allows the tube body to be evacuated in the minimum necessary vacuum area. After the tube body is evacuated, the tip of the inner conductor can be attached or replaced as desired without performing any processing on the tube body, and arbitrary output coupling characteristics can be obtained. Therefore, the output waveguide coupled to this output section can be of any shape and size to obtain desired output coupling characteristics.

[Example of idea]

Examples of this invention will be described below with reference to the drawings. Note that the same parts are represented by the same symbols.

First, a schematic configuration of an example in which the present invention is applied to a linear klystron will be explained with reference to FIG. Intermediate resonant cavity 1 forming part of the klystron tube body
1. A drift tube 12, an output cavity 13, and a collector section 14 are arranged in a vertical line along the tube axis. A coaxial line section 1 consisting of an inner conductor 15 and an outer conductor 16 is provided on a part of the cavity wall of the output cavity 13.
7 is coupled, and cooling water is circulated through the inner conductor 15 as shown by arrow C. The diameters of both the inner and outer conductors are expanded from the middle and are converted into an inner conductor large diameter portion 18 and an outer conductor large diameter portion 19,
A dielectric airtight ring 20 is vacuum-tightly joined between both conductors at these large-diameter portions. As will be described later, both conductors are divided in the axial direction on the part at a dividing part 21 located inward from the position of the airtight ring 20, and when the pipe is completed, they are electrically and vacuum-tightly connected. Become. For example, a rectangular output waveguide 22 connected to an external load is connected to the output section of such a klystron. That is, the wide surface 23 of the short waveguide 22 is connected to the tip flange of the large diameter outer conductor 19, and the large diameter inner conductor 1
8 is inserted into the waveguide by a predetermined length. A movable short plate 2 is provided at one end of the output waveguide 22.
6 is provided, and the other end opening 27 is adapted to be connected to an external high frequency circuit.

Therefore, the inner conductor large diameter portion 18 is provided with an inner conductor divided portion 28 at a position outward from the airtight joint position of the dielectric airtight ring 20, that is, at a position closer to the tip of the inner conductor.
Here, the inner conductor tip 25 is provided with a structure that can be installed or replaced after the tube body is evacuated. In this way, the output cavity 13 and the internal space of the coaxial line section 17 up to the dielectric airtight ring 20 are made into a vacuum region. Cooling water is also circulated within the integrated inner conductor 15 and its large diameter portion 18. The outer conductor also has a structure in which cooling water is circulated inside the outer conductor, as will be described later.

Next, with reference to FIGS. 2 and 3, the structure of the output section of this invention and the coupling structure with the output waveguide connected to an external load will be explained in accordance with the preferred assembly order. FIG. 2 is an exploded half-sectional view of a main part for explaining the assembly sequence, and FIG. 3 is a longitudinal sectional view showing the completed structure. First, the coaxial line section 17 connected to the output cavity of the klystron
The outer conductor 16 is extended with a constant diameter and is converted into an outer conductor funnel-shaped portion 19 with a larger diameter.
1, and a first flange 3 at its large diameter opening end.
2. The outer conductor first to-be-welded thin ring 33 is soldered, and an outer conductor connection step portion 34 is formed on the end surface. The inner conductor 15 is provided coaxially inside the outer conductor, and is composed of an outer inner conductor tube 35 and an inner inner conductor tube 36, and has a refrigerant passage 37 formed therein. An inner conductor funnel-shaped portion 38 is joined to the inner conductor outer tube 35, and an inner conductor connecting ring 39 is joined to the tip thereof. An inner conductor first thin-walled ring 41 having a U-shaped half-section 40 is joined to the inner periphery of the inner conductor connecting ring 39, and a tapered portion 42 is formed at the tip. The inner conductor funnel-shaped part 38 also has an outer cylinder 4 in which a number of oblique slits 43 are bored in a part thereof.
4 are joined, and a plurality of screw holes 45 are formed at the tips thereof. An inner tube threaded cylinder 46 having a female thread is joined to the tip of the inner conductor inner tube 36 . The above structure is preassembled and integrally fixed to the output cavity.

On the other hand, the dielectric airtight ring 20 is assembled as a separate structure as follows. That is, the thin outer wall 48 of the outer conductor bonding ring 47 is hermetically bonded to the outer peripheral surface of the dielectric airtight ring 20 made of ceramic, and a plurality of
An outer reinforcing ring 49 made of Mo is wound around it.
An outer conductor connecting tapered portion 50 is attached to the lower end surface of the outer conductor joining ring 47, and an outer conductor second thin ring 51 to be welded and a second flange 52 are soldered to the outer periphery of the tapered portion 50. An outer conductor tip cylinder 54 is also joined to the outer conductor joining ring 47 so that an annular refrigerant chamber 53 is formed around the outer periphery of the thin outer wall 48, and a cooling pipe 55 is attached to a part of the outer conductor end cylinder 54. A third flange 56 is fixed to the tip of the cylinder 54. A thin inner wall 58 joined to an inner conductor connecting ring 57 is hermetically sealed to the inner circumferential surface of the dielectric airtight ring 20, and a reinforcing ring 59 made of Mo is arranged on the inner circumferential wall. A cylindrical inner conductor second thin ring 60 to be welded is soldered to the inner circumference of the inner conductor connecting ring 57, and the thin inner wall 5
An inner conductor first welding ring 61 is joined to the upper end of the inner conductor 8 . Note that the inner surface of the dielectric airtight ring 20 is coated with a coating layer 20a for preventing multipactors.
is covered. As mentioned above, these structures are assembled individually. In this way, the structure of the dielectric airtight ring part that is airtightly joined between the inner and outer conductors can be assembled independently from the tube body, so these airtight joints can be assembled into an extremely reliable joining structure. It can be easily done. In particular, the airtight joints on the inner and outer surfaces of dielectric airtight rings,
And it is easy to make the application of the anti-multipactor coating layer extremely reliable. Furthermore, no high frequency current flows through the airtight joints between the thin rings of the outer conductor and the thin rings of the inner conductor, so there is little risk of damage to these joints. Then, the outer conductor wall is constituted by the electrically short-circuited outer conductor connecting step, the outer conductor joining ring, the inner conductor connecting ring, and the inner conductor connecting ring, in which a high frequency current flows. It can withstand high power microwave transmission. Furthermore, cooling of the airtight joints of the inner conductor by each welded thin ring and the joints of the dielectric airtight rings is reliably achieved, resulting in excellent reliability. Furthermore, since the dielectric airtight ring is bonded to the large diameter part of the coaxial line, the high frequency electric field density of the dielectric airtight ring is relaxed, damage caused by heating and thermal stress is prevented, and electrons to the dielectric airtight ring are prevented from being damaged. Part of the beam is also reliably prevented from reaching the beam.

A presser ring 62 is prepared separately from the above structure. This presser ring 62 has a large number of diagonal slits 63 and bolt holes 65 through which a plurality of bolts 64 are inserted. In addition, parts constituting the large diameter portion 18 of the inner conductor, that is, an inner tube cylinder 66 for a refrigerant passage and an inner conductor tip portion 25 having an outer tube cylinder 67 are separately prepared. Inner tube cylinder 66
An inner tube funnel-shaped portion 68 is joined to the lower end of the tube, and an inner tube threaded cylinder 69 having a male thread is connected thereto. The lower end of the outer cylinder 67 has a second inner conductor.
A welding ring 70 is joined, and the inner conductor tip 25 is liquid-tightly joined to the upper end of the outer cylinder 67 at an outer pipe joint 71 by soldering.

Now, in assembling the tube, first, as mentioned above, the coaxial line section 17 is placed in the output cavity of the klystron.
The structures up to the inner and outer conductor funnel-shaped parts 31 and 38 are integrally assembled, and the structure of the dielectric airtight ring 20 is bonded thereto. That is, in the outer conductor large diameter portion 19, the outer conductor funnel-shaped portion 3
The outer conductor first welded thin ring 33 of No. 1 and the outer conductor second weld thin ring 51 provided on the outer conductor joining ring 47 are aligned, and the inner conductor large diameter portion
8, fitting the inner conductor first thin ring to be welded 41 of the inner conductor funnel-shaped part 38 and the inner conductor second thin ring to be welded 60 of the inner conductor connecting ring 57,
The outer peripheries of these tips are heliarc welded. These airtight welded portions are indicated by reference numerals 72 and 73, respectively. Then, the first flange 32 and the second flange 52 of the outer conductor are fastened with a plurality of tightening bolts 74, and the holding ring 62 is inserted from above on the inner conductor side and applied to the inner conductor connecting ring 57, and the bolts 64 are
into the screw hole 45 of the outer tube cylinder 44,
Tighten each. As a result, the outer conductor has its outer conductor connecting stepped portion 34 and the outer conductor connecting tapered portion 50 at its large diameter portion, and the inner conductor has its tapered portion 42 and its inner conductor connecting ring 57 at its large diameter portion. are in contact over the entire circumference and electrically short-circuited. The outer diameter of the inner conductor 15 is made larger than the inner diameter of the outer conductor 16 so that the dielectric airtight ring 20 cannot be seen directly from the electron beam path of the output cavity 13. This prevents some of the electrons from passing through the coaxial line portion 17 and reaching the dielectric hermetic ring 20.

In this state, the space from the output cavity to the outer conductor funnel-shaped part 31, inner conductor funnel-shaped part 38 and dielectric airtight ring 20 of the coaxial line section 17 forms a vacuum-tight container. Therefore, in this state, the klystron tube body is exhausted. After that, the inner tube cylinder 66 is attached to the inner tube screw tube 46 of the inner conductor.
Then, attach the outer tube cylinder 67, which forms a part of the large diameter portion of the inner conductor, to the second welding ring 7 of the inner conductor.
0 is fitted into the inner conductor first welding ring 61 and joined at its arc welded portion 75. In this way, the output section is assembled.

When connecting to the output waveguide, the third flange 56 of the outer conductor tip cylinder 54 is aligned with the coupling hole 24 of the output waveguide 22, and the connection is made with a plurality of bolts 76. In operation, the refrigerant passage 77 of the outer conductor and the refrigerant passage 3 of the inner conductor
7, and the refrigerant chamber 53 around the dielectric airtight ring 20, as shown by arrows C, respectively. In particular, in the inner conductor, the refrigerant mainly passes through the slit 43 of the outer tube cylinder 44 to cool the welded thin rings 41 and 60 of both inner conductors, and further passes through the slit 63 of the holding ring 62 to cool the thin inner wall 5.
8. The outer tube cylinder 67 and the inner conductor tip 25 are cooled, and the coolant flows into the inner tube cylinder 66 and is drained to the outside through the inner tube 36 of the inner conductor.

Alternatively, the inner conductor may be divided outside the position of the dielectric airtight ring 20 without forming a large-diameter portion in the coaxial line portion 17, and the tip of the inner conductor may be attached or replaced as necessary. good. However, in that case, it is desirable that a part of the coaxial line portion 17 be bent into an L-shape, for example, so that electrons do not reach the dielectric airtight ring 20.

In the embodiment shown in FIG. 4, a cup-shaped inner conductor tip 25 is screwed in with a threaded portion 81 at a position outward from the dielectric airtight ring 20, and is removably joined. An O-ring 82 is provided inside for liquid-tight sealing. Thereby, the inner conductor tip 25 can be easily replaced from the threaded portion 81 in order to change the protrusion length L and diameter D from the outer conductor tip as desired.

In the embodiment shown in FIG. 5, the outer cylinder 67 of the inner conductor tip 25 is made longer, and pipes 83 and 84 for introducing and discharging refrigerant are provided at the tip. The outer tube cylinder 67 is joined by welding at a position 75 outside the position of the dielectric airtight ring 20. For this output section, an inner conductor tip 25 is provided on the opposite surface of the output waveguide 22.
A coaxial waveguide section 85 protrudes coaxially surrounding the outer tube 67, and the bottom surface of the coaxial waveguide section 85 is electrically coupled to the tip of the outer tube cylinder 67. 86,
86... indicates a bolt for that purpose. In this case as well, the inner conductor tip 25 can be of any length and thickness (the diameter may change halfway) depending on the characteristics of the output waveguide after the tube main body is evacuated.

[Effect of idea]

In this invention having the above configuration, the coaxial line portion is located at the tip of the inner conductor at a position outward from the position of the dielectric airtight ring that is hermetically sealed between the outer circumferential wall of the inner conductor and the inner circumferential wall of the outer conductor. Since the tube has a removable structure, the tube body can be evacuated in the minimum necessary vacuum area, resulting in high exhaust efficiency and easy handling. Further, after the tube main body is evacuated, the length, thickness, and shape of the inner conductor tip can be connected depending on the characteristics of the output waveguide, and the coupling characteristics can be easily finely adjusted. In particular, even with electron tubes such as high-power klystrons, where the tube body is difficult to assemble and exhaust, and the output section cannot be easily changed after completion, the microwave power load, i.e., the external waveguide or oven, is difficult to assemble and exhaust. The output coupling structure to is hardly constrained. That is, since the tip of the inner conductor is configured to be attachable or replaceable after evacuation at a position outward from the position of the dielectric airtight ring, any output waveguide or oven can be adapted. In particular, the present invention can be applied to capacitive coupling as shown in FIG. 3, or inductive coupling structure as shown in FIG. 5, by simply replacing the tip of the inner conductor. As mentioned above, this idea has excellent practicality.

[Brief explanation of drawings]

Figure 1 is a schematic diagram showing an embodiment of this invention;
The figure is an exploded half sectional view of the main part, FIG. 3 is a longitudinal sectional view of the main part, and FIGS. 4 and 5 are sectional views of the main part showing other embodiments of this invention. 13... Output cavity, 15... Inner conductor, 16...
Outer conductor, 17...Coaxial line section, 18...Inner conductor large diameter part, 19...Outer conductor large diameter part, 20...Dielectric airtight ring, 25...Inner conductor tip, 22...Output waveguide Pipe, 28...Inner conductor division part, 67...Inner conductor outer tube cylinder, 81...Threaded part, 85...Coaxial waveguide part.

Claims (1)

[Claims for Utility Model Registration] The outer conductor at one end of the coaxial line section is electrically and vacuum-tightly coupled to the output cavity whose interior is kept in vacuum, and the inner conductor is high-frequency coupled to the output cavity, the interior of which is kept in a vacuum. In the output section of a microwave electron tube, the outer conductor at the other end of the line portion is electrically coupled to the tube wall of the rectangular output waveguide, and the inner conductor is protruded into the inside of the rectangular output waveguide. In the coaxial line section, both the inner conductor and the outer conductor are enlarged to a large diameter near the outer end connected to the short output waveguide, and a dielectric airtight ring is formed between the two conductors at the large diameter portion. The outer conductor portion is vacuum-tightly sealed, and an outer conductor portion extending further outward from the position where the dielectric airtight ring is sealed is removably coupled to the tube wall of the rectangular output waveguide, and An output section of a microwave electron tube characterized in that a tip portion of an inner conductor protruding into the inside of the rectangular output waveguide is connected in a replaceable manner near the outside of a position where the dielectric airtight ring is sealed. .