JPH0453063B2 - - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION This invention relates to improvements in the output section of microwave electron tubes such as klystrons.

[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, in the former case, it is necessary to evacuate the inside of the waveguide, and there is also the disadvantage that it is almost impossible to adjust the coupling characteristics between the coaxial line and the waveguide after the tube is evacuated. In the latter case, it is extremely difficult to assemble a structure that can sufficiently withstand thermal stress on the dielectric airtight wall, multipactor phenomenon, and the like. For this reason, the conventional structure has been limited in that it cannot handle very large amounts of power.

[Purpose of the invention]

The present invention solves the above-mentioned disadvantages, and provides a structure for the output section of a microwave electron tube that minimizes the vacuum area of the output section, sufficiently withstands high power, and is easy to assemble. be.

[Summary of the invention]

This invention relates to a coaxial line section having an inner conductor and an outer conductor coupled to an output cavity of a klystron, for example, and a vacuum-tight seal between an outer circumferential wall of the inner conductor and an inner circumferential wall of the outer conductor of the coaxial line section. In the output section of a microwave electron tube equipped with a dielectric airtight ring, the coaxial line section has an inner conductor and an outer conductor each divided in the line axis direction inward from the sealing position of the dielectric airtight ring. , a thin ring to be welded is joined to each conductor wall of these divided parts, and these thin rings to be welded are hermetically welded to each other, and the conductor walls of these divided parts are electrically short-circuited to each other. It is said that

As a result, the dielectric airtight ring that airtightly connects the inner and outer conductors can be manufactured by itself, and can be assembled into a highly reliable structure.
In addition, the tube body can be evacuated in the minimum necessary vacuum area. Therefore, it is also possible to obtain an output section of the microwave tube and electron tube that can sufficiently withstand relatively high power.

[Embodiments of the invention]

Embodiments of the present 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 in the completed state of the tube, they are electrically and vacuum-tightly connected. Become. A wide surface 23 of a rectangular waveguide 22 is provided at the tip flange portion of the large diameter portion 19 of the outer conductor.
is connected to the coupling hole 24 formed in this waveguide.
From there, the tip portion 25 of the large-diameter inner conductor portion 18 is inserted into the waveguide by a predetermined length. A movable shorting plate 26 is provided at one end of the waveguide 22, and the other end opening 27 is connected to an external high frequency circuit.
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, the structure of the output section will be explained in accordance with its preferred assembly order with reference to FIGS. 2 and 3. 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 outer conductor 16 of the coaxial line section 17 connected to the output cavity of the klystron is extended with a constant diameter and has an outer conductor funnel-shaped section 31 that is converted into an outer conductor large diameter section 19. A first flange 32 and a first welded outer conductor thin ring 33 are soldered to the large opening end, and an outer conductor connecting step 34 is formed on the end surface. An inner conductor 15 is provided coaxially inside this outer conductor, and is composed of an inner conductor outer tube 35 and an inner conductor inner tube 36,
A refrigerant passage 37 is formed inside it. An inner conductor funnel-shaped portion 38 is joined to the inner conductor outer tube 35,
An inner conductor connecting ring 39 is coupled to its tip. 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 4 is attached to the tip of the inner conductor connecting ring 39.
2 is formed. Also connected to the inner conductor funnel-shaped portion 38 is an outer tube cylinder 44 in which a number of diagonal slits 43 are bored.
A plurality of screw holes 45 are formed at its tip. 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 provided at the tip of the cylinder 54.
is fixed. 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 second cylindrical inner conductor is provided on the inner circumference of the inner conductor connecting ring 57.
A thin ring 60 to be welded is soldered, and an inner conductor first weld ring 61 is joined to the upper end of the thin inner wall 58. 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.

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, the inner tube cylinder 66,
and an inner conductor tip 2 having an outer tube cylinder 67
5 are prepared separately. An inner funnel-shaped portion 68 is joined to the lower end of the inner cylinder 66, and an inner threaded tube 69 having a male thread is coupled thereto.
An inner conductor second weld ring 70 is joined to the lower end of the outer cylinder 67. Outer tube cylinder 67
and the inner conductor tip 25 may be joined at the outer tube joint 71 in this state, or if the axial length of the inner conductor tip 25 needs to be adjusted later, After assembly, the outer tube joint portion 71 may be separated in advance so as to be connected liquid-tightly and electrically.

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.
Next, the outer tube cylinder 67 is fitted with its inner conductor second welding ring 70 into the inner conductor first welding ring 61 and joined at the arc welding part 75, and the inner conductor tip 25 is attached to the inner conductor. Install in one piece. and the third one of the outer conductor tip cylinder 54.
The coupling hole 24 portion of the waveguide 22 is matched with the flange 56 and coupled with a plurality of bolts 76 . In this way, the output section is assembled. In operation, refrigerant is circulated through the refrigerant passage 77 of the outer conductor, the refrigerant passage 37 of the inner conductor, and the refrigerant chamber 53 around the dielectric airtight ring 20, as indicated 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.

Note that the coaxial line section 17 may have a structure in which the coaxial line section 17 is divided inward from the position of the dielectric airtight ring 20 without forming a large diameter section. It is desirable that a part of the coaxial line portion 17 is bent into an L-shape, for example, so that the coaxial line portion 17 does not reach there.

〔Effect of the invention〕

In the present invention having the above configuration, the coaxial line portion is located inward from the position of the dielectric airtight ring hermetically sealed between the outer circumferential wall of the inner conductor and the inner circumferential wall of the outer conductor, that is, on the side of the output cavity. Each thin ring to be welded is divided in the axial direction of the line and joined to each conductor wall at this divided portion, and is hermetically welded.
Since the structure of the dielectric airtight ring portion that is airtightly joined between the inner and outer conductors can be assembled independently from the tube body, the airtight joint can have an extremely reliable joining structure. It's easy to do.
In particular, it is easy to make the airtight joint portions on the inner and outer peripheral surfaces of the dielectric airtight ring and the coating layer for preventing multipactors 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 overheating and thermal stress is prevented, and electrons to the dielectric airtight ring are prevented from being damaged due to overheating or thermal stress. Part of the beam is also reliably prevented from reaching the beam. Therefore, in this case, since the coaxial line portion can be constructed in a straight line, the shape of each component is simple and assembly is easy. Furthermore, the tube body can be evacuated without connecting the waveguide and in the minimum necessary vacuum area.
It has good exhaust efficiency and is easy to handle. Furthermore, the tip of the inner conductor of any length can be connected or replaced after the tube is evacuated, and the output conversion characteristics can be easily fine-tuned. As described above, it has an excellent advantage especially as an output part of a microwave electron tube that handles a large amount of power.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an embodiment of the present invention, and FIG.
The figure is an exploded half sectional view of the main part, and FIG. 3 is a longitudinal sectional view of the main part. 13... Output cavity, 15... Inner conductor, 16...
Outer conductor, 17... Coaxial line section, 21... Division section,
18...Inner conductor large diameter part, 19...Outer conductor large diameter part,
20...Dielectric airtight ring, 25...Inner conductor tip, 22...Waveguide, 33...Outer conductor first welded thin ring, 37...Refrigerant passage, 41...Inner conductor first welded target Thin ring, 51... Outer conductor second welded thin ring, 60... Inner conductor second welded thin ring, 66... Inner tube cylinder, 67... Outer tube cylinder, 77... Outer conductor refrigerant passage.

Claims (1)

[Claims] 1. An output cavity whose interior is kept in a vacuum, a coaxial line section having an inner conductor and an outer conductor coupled to this output cavity, and an outer peripheral wall of the inner conductor of this coaxial line section. In the output section of the microwave electron tube, which is equipped with a dielectric airtight ring vacuum-tightly sealed between the inner peripheral wall of the outer conductor and the inner peripheral wall of the outer conductor, the coaxial line section is located above the sealing position of the dielectric airtight ring. The inner conductor and the outer conductor are each divided in the line axis direction on the output cavity side, and a thin ring to be welded is joined to each conductor wall of these divided parts, and these thin rings to be welded are hermetically welded to each other. An output section of a microwave electron tube, characterized in that each conductor wall of the divided section is electrically short-circuited to each other. 2. The coaxial line portion has an inner conductor having a hollow cylindrical shape, and a thin ring to be welded provided on the inner conductor is hermetically welded to the inner periphery of the hollow cylindrical inner conductor, as set forth in claim 1. The output section of the microwave electron tube. 3. The coaxial line section has an inner conductor and an outer conductor each enlarged to a large diameter, and a dielectric airtight ring and a thin ring to be welded at the divided section are hermetically sealed to the large diameter portions, respectively. An output section of the microwave electron tube according to item 1 or 2. 4. The output section of the microwave electron tube according to claim 1, 2, or 3, wherein the inner conductor is configured such that a refrigerant is circulated inside the inner conductor.