JPH03293801A - Waveguide airtight window - Google Patents

Abstract

PURPOSE:To obtain a compact waveguide superior in airtightness by using ceramics as the material of an airtight window and using copper as the material of the waveguide and using stainless steel as the material of an extended waveguide joined to this waveguide. CONSTITUTION:An airtight window main body 15 is made of ceramics, and copper is used as the material of an airtight window waveguide 16. Though it is rectangle, the joinability to the airtight window main body 15 and the productivity are good. Nonmagnetic stainless steel is used as the material of am airtight window extended waveguide 17. Consequently, the joinability to a vacuum-side waveguide 12 and an air or gaseous atmosphere-side waveguide 13 is improved. Thus, compact arrangement is possible, and the reliability of the airtight window is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an airtight window of a waveguide for transmitting microwave power in a heating device for a nuclear fusion reactor or the like.

(Prior Art) Generally, microwaves are oscillated by an oscillation tube such as a talistron, and transmitted to a required location by a waveguide.

Normally, when handling high-output microwaves, the inside of the klystron tube is in a high vacuum, the inside of the waveguide is filled with insulating gas, the microwave antenna section is in the required atmosphere, for example, in the atmosphere or vacuum, and each section in the transmission circuit is placed in a high vacuum. A different atmosphere is maintained each time.

For this reason, a waveguide airtight window is provided at the boundary between each section to allow microwaves to pass through while maintaining airtightness to isolate different atmospheres. Examples of the use of such waveguide airtight windows include accelerators and heating devices for nuclear fusion reactors.

Hereinafter, an outline of a conventional waveguide airtight window will be explained with reference to FIGS. 3 to 5, taking a heating device for a nuclear fusion reactor as an example.

There are several types of heating devices for fusion reactors, but the antenna of the heating device called a reduced hybrid waveband heating device (hereinafter referred to as LHRF heating device) is a bundle of many waveguides that connect directly to the plasma side. It is said to be a grill antenna with an opening.

Figure 3 is a system diagram for one of the waveguides. The microwave ■ oscillated in the klystron ■, which is one oscillation tube, is transmitted through the waveguide airtight window ■ on the ω side of the oscillation tube, and the control unit (I). ) and is guided to the waveguide airtight window ■ on the antenna side.
From the waveguide opening ■ that forms part of the grill antenna,
Injects into plasma ■.

This plasma (1) is held in a toroidal shape within the vacuum container (30) by magnetic force. In addition.

In the figure, ■ is the intermediate waveguide, and ■ is the waveguide airtight window.

This is an insulating gas cylinder that supplies insulating gas into the waveguide between 0 and 0. Furthermore, (10) indicates the area kept in vacuum.
1) indicates a region filled with insulating gas.

Generally, microwaves used for heating plasma etc. often have high output, so in the intermediate waveguide ■,
Insulating gas is supplied from an insulating gas cylinder ■ into the intermediate waveguide (c) in order to prevent discharge phenomena that cause microwave transmission loss and heat generation, etc., but when this is not particularly necessary. The region (11) may be in the atmosphere, and the waveguide airtight windows (1) and (2) cut off the insulating gas or the atmosphere from the vacuum atmosphere inside the klystron (1) or around the plasma (2).

As shown in Figure 4, since it is difficult to manufacture an airtight window with a rectangular cross section, the airtight window (C) is shaped like a disk, and the airtight window body (1
5), the airtight window waveguide (22) that is directly joined to the waveguide (22) is naturally cylindrical. Since a rectangular cross section is required for the waveguide, a flange (19) with a rectangular hole is used to convert the circular shape into a rectangular shape.
, vacuum flanges (20) must be placed on both sides; this configuration requires a significant amount of extra space relative to the original waveguide footprint.

Further, although the airtight window (C) in FIG. 5 has a rectangular cross section, the airtight window waveguide (22) is made of Kovar material for ease of manufacture with the airtight window body (15). Since the Kovar material is a magnetic material, it is affected by the surrounding magnetic field and also has the effect of influencing the magnetic field.

Also, the airtight window main body (15) and the airtight window waveguide (22) are joined.

This material is likely to cause defects when joining the hermetic window waveguide (22), vacuum side waveguide (12), gas atmosphere or atmosphere side waveguide (13).

(Problem to be solved by the invention) Now, it goes without saying that the airtight windows ■ and ■ play an important role in blocking the atmosphere on both sides. Although there is ample space in the configuration and from the perspective of being affected by the magnetic field, the airtight window (c) is located in the area where the waveguides are bundled and is close to the plasma. Because it exists in a region (highly affected by magnetic fields),
It requires no extra space and is required to be constructed of non-magnetic material. Also, as the name suggests, it is an airtight window.

Due to the need for excellent airtightness, reliable manufacture is required.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a waveguide airtight window that is compact and has excellent airtightness without being affected by magnetic fields.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, in the waveguide airtight window of the present invention, the airtight window material is ceramic, and the waveguide material directly bonded to the airtight window to maintain airtightness is copper. The extended waveguide material that is connected to this waveguide is made of stainless steel.

(Function) By creating such an airtight window, the constituent members can be made non-magnetic,
It is possible to manufacture a waveguide airtight window that matches the shape of a rectangular cross-sectional waveguide, and to achieve highly reliable manufacturing.

(Example) FIG. 1 shows an embodiment of the airtight window (1) of the present invention.

The airtight window ■ is located between the vacuum side waveguide (12) and the air or gas atmosphere side waveguide (13), and the airtight window body (15)
.

It consists of an airtight window waveguide (16) and an airtight window extension waveguide (17). The airtight window body (15) is made of ceramic.

Copper is used for the hermetic window waveguide (16). Airtight window body (1
5) The shape may be rectangular in terms of bondability and manufacturability.

In addition, by using non-magnetic stainless steel for the airtight window extension waveguide (17), the bondability with the vacuum side waveguide (12) and the air or gas atmosphere side waveguide (13) is improved. .

FIG. 2 also shows an embodiment of the present invention. As in Fig. 1, the airtight window ■ is located between the vacuum side waveguide (12) and the air or gas atmosphere side waveguide (13), and the airtight window body (15)
, hermetic window waveguide (16), hermetic window extension waveguide (17)
), the airtight window body (15) is made of ceramic;
The hermetic window waveguide (16) uses copper. The difference from FIG. 1 is that the airtight window waveguide (16) is arranged in two halves at both ends of the airtight window body (15), which is a real feature. By dividing the airtight window waveguide (16) into two, the airtight window body (
15), the waveguide shape is reliable and easy regardless of whether it is circular or rectangular.

In addition, regarding the metal coating (18) necessary to prevent microwaves from leaking to the outside of the airtight window body (15) and the required thickness of the coating, the metallized layer applied to the outer periphery of the airtight window body (15) is also considered. In addition, it is a structure that can be adequately covered with a silver brazing material coated with silver brazing that is applied when forming an airtight window. Also, as explained in Fig. 1, by using non-magnetic stainless steel for the airtight extension waveguide (17), the vacuum side waveguide (
12) The bondability with the waveguide (13) on the air or gas atmosphere side is improved.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to obtain a waveguide airtight window having a shape that matches a rectangular cross-section waveguide. By using this material, it is not affected by the magnetic field and has no effect on the magnetic field, and due to the characteristics of the material, the reliability of producing airtight windows is high.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a waveguide airtight window according to one embodiment of the present invention, FIG. 2 is a diagram showing another embodiment, and FIG. 3 is a system diagram of a waveguide of a heating device for a fusion reactor. 4 and 5 are cross-sectional views of conventional waveguide airtight windows. 1... Talaistron 2... Microwave 3.5.
... Airtight window 4 ... Control section 6 ... Waveguide opening 7 ... Plasma 8 ... Intermediate waveguide 9 ...
・Gas cylinder 10...Vacuum region 11...Gas atmosphere or atmosphere 12...Vacuum side waveguide 13...Gas atmosphere or atmosphere side waveguide 15...Airtight window body 16.22... Airtight window waveguide 17...
Extension waveguide 18...Metal coating 19...Flange 20...Vacuum flange 21...Packing

Claims (1)

[Claims] A waveguide airtight window characterized in that a ceramic plate is bonded to the inside of a copper tube, and a stainless steel extension tube is bonded to the end of the copper tube.