JP2003209402A - Air-tight window body structure for microwave - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air-tight window body structure for microwave in which the corrosions of a cylindrical conductor thermal expansion suppressor and a copper cylindrical conductor in a cooling brath are prevented. <P>SOLUTION: A high frequency current passes through a disk-shaped dielectric air- tight window 13 such that the disk-shaped dielectric air-tight window 13 is overheated to high temperature by a dielectric loss. A cylindrical conductor 12 is forcibly cooled by supplying cooling water to a cooling groove 15, the disk-shaped dielectric air-tight window 13 is cooled as well and the thermal destruction of the disk-shaped dielectric air-tight window 13 is prevented. When a cylindrical conductor thermal expansion suppressor 16 comes into contact with the demineralized water of the cooling water in the state of exposing molybdenum in the periphery, the cylindrical conductor thermal expansion suppressor 16 is oxidized and corroded by the lack of cooling during the production process and the operation of an air-tight window body structure 4 for microwave and it is also possible for a cylindrical conductor 12 to be corroded by long-time exposure in the cooling water. The surface of the cylindrical conductor thermal expansion suppressor 16 of molybdenum is covered with a protecting layer 17 of nickel such that the cylindrical conductor thermal expansion suppressor 16 can be shielded from the cooling water and can be protected from the corrosion caused by water. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave hermetic window structure having a cooling jacket for cooling a dielectric hermetic window.

[0002]

2. Description of the Related Art Heretofore, as a microwave tube using this type of airtight window structure for microwaves, for example, Japanese Patent Publication No.
The klystron device described in Japanese Patent No. 27541 is known. The klystron device disclosed in Japanese Patent Publication No. 1-27541 has an electron gun for irradiating an electron beam, the electron beam irradiated by the electron gun is amplified by a high frequency amplifier, and the amplified electron beam is It is guided to the output waveguide, and is output from a hermetic window made of a dielectric material which is provided in the output waveguide and airtightly separates the atmosphere and the vacuum in the tube.

In general, the hermetic window is made of a disk-shaped dielectric and the output waveguide is made of copper. Since the thermal expansion coefficient of these airtight windows and the copper of the output waveguide are different,
The output waveguide has a thin structure so that it can follow a slight contraction of the hermetic window. Furthermore, in order to allow the output waveguide to follow even a slight contraction of the airtight window, thermal expansion of the output waveguide is suppressed around the output waveguide in the portion where the airtight window is located, for example, molybdenum ( A ring-shaped copper cylindrical conductor thermal expansion suppressor made of Mo) is attached.

On the other hand, since a very large high-frequency power passes through the airtight window of the output waveguide, the airtight window is overheated to a high temperature due to dielectric loss, which adversely affects the frequency characteristics. For this reason, a cooling groove serving as a cooling tank in which cooling water flows is formed around the output waveguide in a portion where the airtight window is located, and the airtight window is forcibly cooled.

[0005]

However, the copper cylindrical conductor thermal expansion suppressor is corroded by oxidation due to insufficient cooling during the manufacturing process or operation of the output waveguide, and the output waveguide itself is cooled for a long time as well. It has a problem that it may be exposed to water and cause corrosion.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a microwave hermetic window structure in which corrosion of a tubular conductor thermal expansion suppressor and a copper tubular conductor is prevented in a cooling tank. To aim.

[0007]

SUMMARY OF THE INVENTION The present invention is directed to a plate-like airtight window formed of a dielectric material, a copper tube conductor airtightly connected to the outer peripheral surface of the window, and an airtight window of the tube conductor. A cooling jacket having a cooling tank formed around a portion having a cooling liquid and containing a cooling liquid; and a cooling jacket provided on the outer periphery of a portion around the airtight window of the tubular conductor and positioned in the cooling tank of the cooling jacket. A tubular conductor thermal expansion suppressor made of metal that suppresses thermal expansion of the tubular conductor, and at least a portion of the tubular conductor thermal expansion suppressor that is in contact with the cooling liquid in the cooling tank of the tubular conductor is covered with an ionization tendency than the tubular conductor thermal expansion suppressor. A protective layer formed of a low metal or at least one of a substance layer of a non-water-soluble sealant that covers at least a portion of the cylindrical conductor thermal expansion suppressor in contact with the cooling liquid in the cooling tank and has a cylindrical conductor thermal expansion coefficient. In the cooling tank of the suppressor By covering at least the part in contact with the cooling liquid with a protective layer formed of a metal having a lower ionization tendency than the tubular conductor thermal expansion suppressor, the protective layer is corroded by the cooling liquid because it has a lower ionization tendency than the tubular conductor thermal expansion suppressor. It is difficult to cool the cylinder conductor thermal expansion suppressor from being cooled, or by covering at least a portion of the cylinder conductor thermal expansion suppressor that is in contact with the cooling liquid with a substance layer of a non-water-soluble sealant, the cooling liquid Since the cylindrical conductor thermal expansion suppressor is covered with the material layer, the cylindrical conductor thermal expansion suppressor is shielded from the cooling water and is less likely to be corroded by the cooling liquid.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION A klystron device according to an embodiment of an airtight window structure for microwaves of the present invention will be described below with reference to the drawings.

A klystron device of an ultra-high power straight line type having an output of, for example, 1 MW has a tube body 1 as shown in FIG. 2, and the tube body 1 is provided with an electron gun 2 for generating an electron beam at its base end. Next to the electron gun 2, a high-frequency amplifier 3 having a cavity for amplifying an electron beam from the electron gun 2 and converting the electron beam into a microwave is disposed. A microwave airtight window structure 4, which is a high-frequency airtight window structure that serves as an output waveguide portion that outputs a high frequency wave such as microwaves to the outside of the tube, is provided, and on the straight line of the high-frequency amplification section 3. The collector section 5 receives the electron beam that has not been converted to microwaves.
Is provided.

Around the electron gun 2, an insulating oil filling tank 6 for accommodating the electron gun 2 and the insulating oil in which the electron gun 2 is dipped is arranged, and adjacent to the insulating oil filling tank 6. A converging magnet device 8 to which the electromagnet 7 is attached is arranged, and an evaporative cooling boiler 9 for accommodating and cooling the collector portion 5 is arranged adjacent to the converging magnet device 8.

Now, the hermetic window structure 4 for microwaves will be described with reference to FIG.

As shown in FIG. 1, a waveguide 11 for introducing microwaves from the high frequency amplifier 3 is provided, and a cylindrical conductor 12 made of copper is hermetically brazed to the waveguide 11, 12
An outer peripheral surface of a disk-shaped dielectric airtight window 13 made of ceramic, which is a dielectric, is attached to the inner periphery of the airtightly in a brazed manner. And, by this disk-shaped dielectric airtight window 13,
The vacuum on the waveguide 11 side and the atmosphere on the output side are partitioned. Since the disk-shaped dielectric airtight window 13 has a smaller coefficient of thermal expansion than the cylindrical conductor 12, when the disk-shaped dielectric airtight window 13 slightly contracts during cooling after brazing to a high temperature. The cylindrical conductor 12 has a thin structure so that the cylindrical conductor 12 can follow.
Also, a cylindrical conductor located around the disk-shaped dielectric airtight window 13
The reason why copper is used for 12 is that copper is well sealed with ceramics, and the high-frequency resistance of the surface is small so that it is difficult to generate heat. A cooling jacket 14 that cools the disk-shaped dielectric airtight window 13 by forcibly cooling the cylindrical conductor 12 that also serves as a support frame is provided around the cylindrical conductor 12 in which the disk-shaped dielectric airtight window 13 is located. Inside the cooling jacket 14, a cooling groove 15 is formed which forms a cooling water passage as a cooling tank through which pure water cooling water flows.

Further, a ring-shaped cylindrical conductor thermal expansion suppressing member 16 made of molybdenum (Mo) is mounted on the outer periphery of the cylindrical conductor 12 in which the disk-shaped dielectric airtight window 13 is located in the cooling groove 15. The cylindrical conductor thermal expansion suppressor 16 is a metal different from molybdenum, and is closely covered with a protective layer 17 made of nickel (Ni) having a smaller ionization tendency than molybdenum. The cylindrical conductor thermal expansion suppressor 16 is provided on the outer peripheral surface of the cylindrical conductor 12 so that the cylindrical conductor 12 can follow the slight thermal expansion of the disk-shaped dielectric airtight window 13 during heating before brazing. Further, the protective layer 17 is resistant to brazing and has no adverse effect on the cylindrical conductor thermal expansion suppressor 16 of molybdenum as a base material, and nickel or nickel alloy is used as a metal having a low possibility of corrosion by water. The thickness of the nickel to be adhered is set so as not to impair the mechanical properties of the cylindrical conductor thermal expansion suppressor 16 of the base material.

A microwave tube output section 18 for output is formed on the output end side of the cylindrical conductor 12.

Next, the operation of the above embodiment will be described.

First, when an electron beam is emitted from the electron gun 2, the high frequency amplifier 3 amplifies the electron beam, converts the electron beam into a microwave, and guides it to the microwave hermetic window structure 4.

In the microwave airtight window structure 4, the microwave is taken out of the tube through the disk-shaped dielectric airtight window 13 and output from the microwave tube output section 18.

Since this klystron device has a large electric power, a very large high-frequency current passes through the disk-shaped dielectric airtight window 13, so that the disk-shaped dielectric airtight window 13 is damaged by dielectric loss. If it is overheated to a high temperature, the disk-shaped dielectric airtight window 13 may be adversely affected and the output frequency characteristics may be adversely affected. However, by supplying cooling water to the cooling groove 15, the cylindrical conductor 12 is forcibly cooled, and the cylindrical conductor 12
The disk-shaped dielectric airtight window
13 is also cooled to prevent thermal destruction of the disk-shaped dielectric airtight window 13.

On the other hand, when the cylindrical conductor thermal expansion suppressor 16 is in direct contact with the cooling water with molybdenum being exposed to the surroundings, due to insufficient cooling during the manufacturing process and operation of the microwave hermetic window structure 4, etc. , The cylindrical conductor thermal expansion suppressor 16 oxidizes and corrodes, and similarly, the cylindrical conductor 12 may be corroded by being exposed to cooling water for a long time. By covering the surface of the expansion suppressing body 16, the cylindrical conductor thermal expansion suppressing body 16 can be shielded from the cooling water and protected from corrosion by water.

Further, the protective layer 17 is a cylindrical conductor thermal expansion suppressor.
Since the mechanical properties of 16 are not impaired, the trackability of the cylindrical conductor 12 with respect to the disk-shaped dielectric airtight window 13 is not impaired, and the disk-shaped dielectric airtightness is maintained when the microwave airtight window structure 4 operates. Even if the window 13 becomes high temperature and is cooled, the vacuum-sealed joint between the disk-shaped dielectric airtight window 13 and the cylindrical conductor 12 is not destroyed.

Next, another embodiment will be described with reference to FIG.

The microwave airtight window structure 4 of the embodiment shown in FIG. 3 is a cylindrical conductor in which the protective layer 17 is formed in the microwave airtight window structure 4 of the embodiment shown in FIG. Cooling groove 15 in which cooling water flows including thermal expansion suppressor 16
The material layer 21 of a silica-based glass paste having heat resistance and airtightness of an inorganic protective film that is highly fluid and not water-soluble but serves as a sealant is applied to the inner peripheral surface of the.

As described above, even when the material layer 21 is formed, the material layer 21 can be shielded from the cooling water, so that it can be protected from corrosion by the cooling water.

In this case, the same effect can be obtained without forming the protective layer 17.

Further, although the cylindrical conductor thermal expansion suppressor 16 is formed in a ring shape in the above embodiment, the same effect can be obtained by forming it in a C shape or a wire shape.

Further, the protective layer 17 is formed on the entire periphery of the cylindrical conductor thermal expansion suppressor 16, and the protective layer 17 or the material layer is formed.
21 may be formed at least only in a portion that comes into contact with the cooling water.

[0027]

According to the present invention, since the protective layer has a lower ionization tendency than the tubular conductor thermal expansion suppressor, it is less likely to be corroded by the cooling liquid, and is blocked by the tubular conductor thermal expansion suppressor for cooling, or By covering at least the portion of the cylindrical conductor thermal expansion suppressor that is in contact with the cooling liquid in the cooling tank with a material layer of a non-water-soluble sealing agent, the material layer covers the cylindrical conductor thermal expansion suppressor so that it is shielded from the cooling water. As a result, the cooling liquid is less likely to be corroded, and corrosion of the tubular conductor thermal expansion suppressor and the copper tubular conductor in the cooling tank can be prevented.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view showing an embodiment of an airtight window structure for microwaves of the present invention.

FIG. 2 is a sectional view showing a klystron device using the above microwave hermetic window structure.

FIG. 3 is a cross-sectional view showing a microwave hermetic window structure of another embodiment of the same as above.

[Explanation of symbols]

4 Airtight window structure for microwave 12 Cylindrical conductor 13 Disc-shaped dielectric airtight window 14 Cooling jacket 15 Cooling groove as a cooling tank 16 Cylindrical conductor thermal expansion suppressor 17 Protective layer 21 Material Layer

Claims (5)

[Claims] 1. A plate-shaped airtight window formed of a dielectric material, a copper tubular conductor airtightly connected to an outer peripheral surface of the airtight window, and a tubular conductor formed around a portion of the tubular conductor having the airtight window. A cooling jacket having a cooling tank in which a cooling liquid is stored; and a thermal expansion of the tubular conductor, which is provided on the outer periphery of a portion around the airtight window of the tubular conductor and is located in the cooling tank of the cooling jacket. A tubular conductor thermal expansion suppressor made of metal, and a protective layer formed of a metal that covers at least a portion of the tubular conductor thermal expansion suppressor that contacts the cooling liquid in the cooling tank and has a lower ionization tendency than the tubular conductor thermal expansion suppressor. An airtight window structure for microwaves, comprising: 2. An airtight window for microwaves as set forth in claim 1, further comprising a substance layer of a non-water-soluble sealant which covers at least a portion of the cylindrical conductor thermal expansion suppressor in contact with the cooling liquid in the cooling tank. Structure. 3. A plate-like airtight window made of a dielectric material, a copper tubular conductor airtightly connected to an outer peripheral surface of the airtight window, and a tubular conductor formed around a portion of the tubular conductor having the airtight window. A cooling jacket having a cooling tank in which a cooling liquid is stored; and a thermal expansion of the tubular conductor, which is provided on the outer periphery of a portion around the airtight window of the tubular conductor and is located in the cooling tank of the cooling jacket. A microwave, comprising: a metal tubular conductor thermal expansion suppressor; and a material layer of a water-insoluble sealing agent that covers at least a portion of the tubular conductor thermal expansion suppressor that contacts the cooling liquid in a cooling tank. Airtight window structure. 4. The hermetic window structure for microwaves according to claim 1, wherein the protective layer is formed of a metal containing at least nickel. 5. The hermetic window structure for microwaves according to claim 2, wherein the material layer is a silica-based inorganic protective film.