JPH0286031A - gyrotron - Google Patents

Abstract

PURPOSE:To suppress the leakage of microwaves and efficiently perform the exhaust of an output window section by connecting the inside gap of an insulating ring between a collector section and the output window section to a vacuum chamber and communicating it to the space in an output side wave guide with slits. CONSTITUTION:A gap 34 inside a ceramic insulating ring 26 between a collector section 15 and an output window section 16 is communicated to a vacuum chamber 35 around a collector section wave guide wall 18b. Ventilating slits 37 are provided at the end section of this wave guide wall 18b to face the wave guide wall 18c of the output window section at a gap G, and a connecting flange 23b with high mechanical strength and welding thin flanges 23c and 23d are integrally provided on the outer periphery of the wave guide wall 18c. Sealing rings 27 and 28 are brazed on both faces of the insulating ring 26. Flanges 23a and 23b are connected with the insulating ring 26, a bolt 31 and a nut 32. The exhaust of the inside gap of the insulating ring is efficiently performed with such a simple structure, and the mechanical strength can be thoroughly maintained.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) This invention relates to a gyrotron, and particularly to a gyrotron having a structure in which an output waveguide wall is electrically divided into a plurality of parts along the tube axis. Regarding Tron.

(Prior Art) As is well known, a gyrotron is an electron tube whose operating principle is cyclotron maser action, and is being used as a high-frequency high-power source in the millimeter wave to submillimeter wave band. A type of gyrotron consists of a cylindrical electron beam formed by a group of electrons in cyclotron motion, and an electromagnetic wave that interacts with this electron beam in a single resonant circuit such as a resonant cavity, and is accumulated in the resonant circuit. The gyromonotron, which generates oscillation when the energy of the electron beam is lost due to the electromagnetic energy generated by the electromagnetic wave, the gyroklystron, which uses a similar electron beam and multiple resonant cavities to amplify electromagnetic waves, and the similar electron beam and transmission circuit. Examples include a gyro traveling wave tube that interacts with a traveling wave in the transmission circuit, and a backward wave gyrotron that combines with a backward wave in a transmission circuit.

The operating frequency of the gyrotron is approximately several tens of IIZ.
to 100s) Iz is common, and when converted to wavelength, it is about 21 to several I. Therefore, compared to klystrons and traveling wave tubes, the wavelength is two to three orders of magnitude shorter, and the gyrotron's high-frequency circuit requires extremely high dimensional accuracy for each part.

Such a gyrotron usually consists of an electron gun section, a tapered electron beam introduction section, a resonant cavity section, a tapered guide section, a collector section, an output window section, and the like.

By the way, in the gyrotron, the inner diameter of the resonant cavity that generates microwaves or the cut-off tunnel on the electron gun side is very thin, and the range from the above-mentioned tens of GHz to more than 100 G11z.
In the case of a band, although there are differences depending on the oscillation mode, the number is approximately 1- to lha. Therefore, the electron gun part and the collector part are separated at this part, and the exhaust conductance is extremely low. For this reason, exhaust pipes are generally provided on the electron gun side and the collector side, respectively, and an ion pump is connected to them. In a structure in which an exhaust pipe is connected to a part of the collector section, that is, a part of the output waveguide, a slit for ventilation is formed in a part of the waveguide wall, a vacuum chamber is provided around the periphery, and the exhaust pipe is connected to this. A structure that does this is disclosed in, for example, Japanese Patent Application Laid-Open No. Sho H-13238.

On the other hand, among the output side waveguides, the collector part waveguide and the output window part waveguide are divided into multiple parts by insulating rings and electrically separated, and the amount of captured electron beam in each part can be measured and output In some cases, the waveguide in the window section is configured to have a lower potential than the collector section to suppress the electron beam from flowing into the output window. FIG. 6 is a schematic configuration diagram of the same, in which reference numeral 11 is an electron gun section that generates a hollow electron beam, 12 is a tapered electron beam introduction section that is disposed downstream of the electron beam and whose diameter gradually becomes smaller, and 13 14 is a resonant cavity portion continuously provided downstream thereof; 14 is a tapered guide portion continuously provided downstream thereof and gradually increases in diameter; 15 is a cylindrical collector portion disposed downstream thereof; 1G is an output window portion located downstream thereof and has a ceramic airtight window; 17 is a waveguide coupling flange; L8a, 18b, and Hlc are copper waveguide walls through which electron beams or high-frequency waves pass and are transmitted; Solenoid of the magnetic field device, 20.21 is a waveguide separation part, 22 is an insulating ring, 23 is a connecting flange, 2
4 represents a fastening bolt/nut. In this way, the waveguide separation section brings the two waveguide walls close to each other with a predetermined small gap G through the ceramic insulating ring 22, thereby electrically insulating and separating them, and at the same time preventing high frequency waves. We are trying to prevent it from leaking to the outside.

(Problems to be Solved by the Invention) The conventional techniques described above are capable of maintaining the degree of vacuum inside the tube,
Alternatively, it is effective in achieving the purpose of electrically separating the output side waveguide. Therefore, if we consider a configuration in which these are combined, the waveguide separation section, the ventilation slit, and the vacuum chamber will be provided independently, making the structure complex and increasing the length in the tube axis direction. Extra consideration must also be given to mechanical strength.

This invention integrates the separation section on the output waveguide side, the exhaust slit section, and the chamber section, and provides a highly reliable gyrotron that maintains sufficient mechanical strength with a relatively simple structure. The purpose is to

[Structure of the Invention] (Means for Solving the Problems) The present invention provides vacuum chambers provided on the outer periphery of output waveguides that are electrically isolated by an insulating ring, facing each other in close proximity with a predetermined gap between them. The gap between the collector waveguide and the output window waveguide and the inner gap of the insulating ring are connected to each other, and the ventilation slit is adjacent to the gap between the separated waveguides. The gyrotron is formed on at least one of a wave tube wall and an output window waveguide wall.

(Function) According to the present invention, the mutual gap between the waveguides that communicate with the inner gap of the insulating ring provided between the collector part waveguide and the output window part waveguide on the output side and are separated from each other and A vacuum chamber and an exhaust pipe are provided that communicate with the inside of the waveguide through a ventilation slit provided adjacent to it, so that the pipe does not become undesirably long in the axial direction, and mechanical strength is maintained. This makes it possible to suppress microwave leakage and efficiently exhaust air from the collector section and the output window section, thus making it possible to obtain a highly reliable gyrotron.

(Embodiment) Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Note that the same parts are represented by the same symbols.

The main parts will be explained with reference to FIGS. 1 to 4.

A ceramic insulating ring 2B is interposed between the collector section 15 and the output window section 16 to electrically isolate them. A gap 34 is formed along the inside of this insulating ring 26, and this gap 34 communicates with a vacuum chamber 35 provided on the outer periphery of the waveguide wall 18b of the collector section. The chamber 35 includes a collector waveguide wall 18b1, a disk wall 35a1, a cylindrical wall 35b1, and one connecting flange 2.
An exhaust pipe 36 is connected to a part of the cylindrical wall 35b, and a vacuum pump and an ion pump (not shown) during manufacturing are connected to the exhaust pipe 36.

A plurality of ventilation slits 37 are provided at the end of the waveguide wall 18b of the collector section. This ventilation slit 3
7 is constructed by laminating and soldering a plurality of metal rings 3B, 38 and a metal ring 39 at the end as shown in FIGS. 3 and 4.

The metal ring 38 has stepped protrusions 38a formed on the outer periphery at 90'' intervals, and by sequentially stacking them on the end of the waveguide wall 18b, the areas where there are no protrusions 38a are vented in the circumferential direction. Thus, the waveguide wall of the collector section terminates at the end inside the chamber 35, and a plurality of ventilation slits are formed there.

On the other hand, the beam upstream end surface of the waveguide wall 18c of the output window section provided with an output window (not shown) is located at the collector section waveguide wall 1.
It faces the end face of 8b with a predetermined gap G therebetween. On the outer periphery of the output window waveguide wall 18C, a connecting flange 23b having high mechanical strength such as thick-walled stainless steel is provided.
are fixed by soldering. Both flanges 23a 2
A thin flange 23c for welding is provided on the opposing surfaces of 3b.
, 23d are integrally provided. Sealing rings 27 and 28 are provided on both sides of the insulating ring 2B, respectively.
are hermetically soldered. Also each sealing ring 27.28
are attached to the sealing bodies 29 and 30, and their tips are hermetically welded to the respective thin flanges 23c and 123d at the outer periphery welds B and B.

Both flanges 23a, 23b are connected by a plurality of fastening bolts ai, 31... and nuts 32, 32... provided across the outside of the insulating ring 26 and the sealing ring 27, 28. , mechanically coupled with adjustable mutual spacing. Note that an insulating washer 33 is fitted to one flange 23b, thereby electrically insulating both flanges 22 and 23. Thereby, both waveguides 18b and 18c are electrically insulated and separated.

In this way, the vacuum chamber 35 has a plurality of ventilation slits 37 formed in the waveguide wall, and a space between the waveguides facing each other. 12G, it communicates with the inner space of the waveguide, and at the same time communicates with the inner cavity 34 of the insulating ring 26. Thereby, the inside of the waveguide and the inner gap of the insulating ring can be efficiently evacuated with a relatively simple configuration, and sufficient mechanical strength can be maintained. Therefore, the tube can be constructed without becoming undesirably long in the tube axis direction.

Furthermore, the width g in the axial direction of the ventilation slit 37 and the gap G is an integral multiple of about 1/2 of the wavelength λ of the operating center frequency of this gyrotron (g is about nλ/2, n The dimensions are set to correspond to 1, 2, 3...).

Note that this dimension g is desirably set within the range of λ/2, ±20%. Further, the depth d of the slit extending outward from the inner circumferential surface of the waveguide wall 18b due to the protrusion 38a of the metal ring forming the slit 37 is at least 1/1O of the wavelength λ (d≧λ/10 ). As a result, on the inner circumferential surface of the waveguide, the areas with and without slits in the circumferential direction are substantially eliminated and become equivalent to the case of slits, so that no disturbance of high frequency current occurs. Therefore, there is almost no high frequency leakage to the chamber side, and there is no possibility that an electromagnetic field of an undesired mode will be generated within the waveguide.

Setting the slit dimensions like this is suitable for a gyrotron with a relatively short operating wavelength, and is particularly suitable for a gyrotron with a frequency of 100 (dlz or more), for example.The width g of each slit depends on the processing accuracy of the metal ring. Furthermore, the dimension g of the gap G can be easily set to a predetermined dimension by adjusting the amount of adjustment when the connecting flanges are fastened.In the embodiment shown in FIG. It is extended and fixed to the outer periphery of the collector portion waveguide wall 18b by soldering.A plurality of relatively large diameter holes are provided along the circumferential direction between this joint portion 42 and the flange inner peripheral wall 41. A ventilation hole 43 is formed to communicate the chamber 35 and the auxiliary chamber 44.A metal ring 3g is attached to the tip of the waveguide wall 18b that projects into the area of the auxiliary chamber 44.
, 39 are laminated and soldered together, and a plurality of slits 37 and gaps G are formed to allow ventilation. The sealing rings 27 and 28, which are hermetically sealed to the insulating ring 26, have diaphragm parts 27a and 28a that can be expanded and contracted in the axial direction.
is provided.

With this configuration, the dimensions of the gap G can be set easily and with high precision, and since the slit and the gap G are fixed at the adjacent waveguide wall portions via fastening bolts and nuts, the waveguide wall during operation can be easily set. Even if there is thermal expansion, there is almost no change in the width g of the slits and gaps, and deterioration of operating characteristics can be suppressed.

In the above embodiment, the ventilation slit is formed at the downstream end of the beam of the waveguide wall of the collector section, but the ventilation slit is not limited to this. You may. Further, ventilation slits may be formed in both waveguide walls, respectively.

Then, the vacuum chamber may be configured in a region immediately inside the insulating ring, and both separated waveguide walls may be directly fixed to the respective connecting flanges.

Thereby, changes in the width dimensions of the slit and the gap G during operation can be made even smaller to the extent that they can be ignored.

In this manner, a vacuum chamber integrally communicated with the divided portion of the waveguide through the slit can be provided, and an efficient evacuation effect can be obtained without substantially increasing the length in the tube axis direction. Also, almost no high frequency leakage occurs.

[Effects of the Invention] As explained above, according to the present invention, a vacuum chamber is provided on the outer periphery of the collector portion and communicates with the inner gap of the insulating ring provided between the collector portion and the output window portion, and the slit Since it communicates with the output-side waveguide internal space, leakage of microwaves is suppressed, and the collector portion and output window portion are efficiently exhausted, resulting in stable operation.

As a result, a highly reliable gyrotron can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view showing the main parts of a gyrotron according to an embodiment of the present invention, FIG. 2 is an enlarged view of the main parts, FIG. 3 is a sectional view of the main parts, and FIG. 4 is a side view thereof. , FIG. 5 is a half sectional view of a main part showing another embodiment of the present invention, and FIG. 6 is a schematic vertical sectional view showing a conventional structure. 15... Collector part, 16... Output window part, 18b... Collector part waveguide wall, 18c... Output window part waveguide wall, 23a, 23b... Connection flange, 2B...・Insulating ring, 34...Gap, 35...Chamber, 3B...Exhaust pipe, 37...Slit for ventilation, G...Gap between division parts, 38.39...Metal ring. Applicant's agent Patent attorney Takehiko Suzue 3V Figure Figure

Claims (1)

[Claims] The waveguide wall of the collector section and the waveguide wall of the output window section are electrically separated by an insulating ring, and an exhaust pipe is connected to the outer periphery of the waveguide wall of the collector section. In a gyrotron, a vacuum chamber is provided, and the chamber and a waveguide internal space are communicated with each other through a plurality of ventilation slits formed in a wall of the waveguide, and the chambers are spaced apart from each other by a predetermined gap. communicates with the waveguide internal space through the gap between the collector part waveguide wall and the output window part waveguide wall that are close to each other, and
The ventilation slit is also in communication with the inner cavity of the insulating ring, and the ventilation slit is formed in at least one of the collector waveguide wall or the output window waveguide wall adjacent to the waveguide mutual gap. A gyrotron that is characterized by the ability to