JPS5847817B2 - microwave tube device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electron beam rectilinear microwave tube device such as a traveling wave tube or a klystron, and particularly relates to an improvement of a periodic magnetic field generating device thereof.

Generally known traveling wave tubes are, for example,
As shown in Japanese Patent No. 425, etc., a periodic magnetic field generator is provided in which donut-shaped permanent magnets are arranged along the axis around the outer periphery of a slow wave circuit.

Then, there is a ferrule (ferrule) that houses the partition disk made of a magnetic material that is magnetically coupled to the magnet and the electron beam path.
u & ) forms a periodic magnetic field and focuses the electron beam.

Such a conventional periodic magnetic field generator has a large amount of leakage magnetic flux from the magnet, and therefore has no choice but to be large and heavy.

For this reason, it could not be used satisfactorily for purposes such as mounting on artificial satellites.

Also, since the magnet protrudes outside the slow wave circuit, it is susceptible to external magnetic influences.

The present invention has been made in view of the above-mentioned circumstances, and is an improvement of a straight-beam microwave tube that can be extremely miniaturized, and in particular, its periodic magnetic field generator.

Examples thereof will be described below with reference to the drawings.

Note that the same parts are given the same symbols.

The microwave tube device shown in FIGS. 1 and 2 is a high-power traveling wave tube device having a cavity-coupled slow-wave circuit.
Only the slow wave circuit part is shown in the figure.

That is, this slow wave circuit 11 has an outer circumferential wall 13 which also serves as a wall of a vacuum envelope, and a plurality of partition plates, such as partition disks 14, 14, arranged regularly in the axial direction.

The partition disk 14 is made of a magnetic material, and coupling slots 15, 15, . . . are formed in a part thereof.

The cavity outer peripheral wall 13 is made of a non-magnetic material, and the partition disk 14
is airtightly joined.

Therefore, a through hole 16 is formed in the center of the partition disk 14 through which the electron beam e shown by the dotted line passes.

Cylindrical permanent magnets 17, 17, .
・ are mounted so that their magnetic poles are aligned along the axial direction.

For one partition disk 14, a magnetic pole of the same polarity, for example S
The poles are connected, and the adjacent partition disk is connected to a magnetic pole of another polarity, ie, a north pole.

As a result, a strong magnetic field that extends to the electron beam path is formed near the mutual gap between the magnets connected to adjacent partition disks.

This magnetic field becomes a periodic magnetic field that is formed along the path of the electron beam as shown by the arrow.

Now, the permanent magnets 17, 17, . . . are also made of a material with good conductivity.

In this way, the cavity resonator 12 is formed by the outer peripheral wall 13, the adjacent partition disks 14, 14, and the adjacent permanent magnets 17, 17.
is configured.

This high frequency interaction between the cavity resonator 12 and the electron beam e takes place in the gap, and the permanent magnet 1
7, 17, . . . also serve as so-called ferrules for forming a high frequency electric field in the gap of the resonator.

In addition, in order to adjust the distribution of the periodic magnetic field as necessary, the partition disks 14 that are adjacent to each other on the outside of the cavity outer peripheral wall 13 are
, 14 are provided with nine inter-disk magnetic resistance adjusting pieces 18, 1B, .

That is, if adjacent partition disks are magnetically short-circuited, the magnetic resistance of a magnetic circuit including two adjacent magnets is minimized, and the magnetic flux density in the electron beam path is increased.

In this way, the magnetic flux density or magnetic field distribution can be changed locally.

The permanent magnet 17 used is one that is small, has sufficient coercive force, releases little gas, and has at least good electrical conductivity on its surface as described above.

Suitable magnets for this purpose include rare earth magnets such as samarium-cobalt magnets, which have recently been developed as high-energy products, or spinodal magnets.

The inner diameter of the through hole 16 in the partition disk is made larger than the inner diameter of the magnet 17 to reduce the leakage magnetic flux that goes around the inside of the magnet itself.

In the microwave tube device of the present invention having the above structure, the magnet is placed as the periodic magnetic field generating device at the ferrule in the inner center of the partition disk. The magnetic flux utilization efficiency is high, so the device can be made smaller.

Furthermore, since the magnet is completely housed inside the vacuum envelope, it is less susceptible to external magnetic influences, and a stable periodic magnetic field distribution can be maintained.

The embodiment shown in FIG. 3 uses a magnet 17 as a magnetic field generator.
The magnetic pole pieces 21, 21, . . . are connected to the magnetic pole faces of the magnetic pole pieces 21, 21, .

The pole piece 21 is coupled to the inside of the magnetic pole face so that the magnetic flux is efficiently guided into the electron beam path, and the inner diameter of the through hole 16 of the partition disk 14 is set to the inner diameter of the magnet. It is made smaller so that the leakage magnetic field that forms between this and the pole piece can also be actively used to focus the electron beam.

This further increases the efficiency with which the magnet is used, and allows the periodic magnetic field to be strongly distributed in the electron beam path.

Furthermore, as shown in FIG. 4, the pole piece 21 can be bent along the inner wall of the magnet.

This allows the magnetic field to extend further into the electron beam path,
Moreover, the magnet and the pole piece and the magnet and the partition disk can be easily fixed.

In the device shown in FIG. 5, one cylindrical magnet 17 is fixed to the center of the partition disk 14 to form a ferrule of a cavity resonator and arranged alternately in the axial direction.

The partition disk is made of non-magnetic material.

In this case, it is not possible to adjust the magnetic field distribution externally, but if you set the magnetization strength and spacing of the magnets appropriately in advance and eliminate the need for adjustment, the structure becomes extremely simple. It is especially suitable for small traveling wave tubes and other devices where the complexity of the structure needs to be reduced.

In the device of the embodiment shown in FIG. 6, a conductive layer 22 made of a non-magnetic material and having better electrical conductivity and thermal conductivity than the material of the magnets and good heat resistance is formed on the outer surface of the magnets 17, 17, . . . This is what I did.

Suitable materials for this conductive layer include copper, nickel, and the like.

As a result, while satisfying the electrical characteristics of the cavity resonator,
For example, even if a portion of the electron beam hits the ferrule portion, ie, the magnet, outgassing and melting can be prevented.

At the same time, by adopting this structure, it is possible to use a magnet having poor conductivity, such as a ferrite magnet.

In addition, if a so-called magnetic shunt material is used as the partition disk that is coupled to the magnet and serves as a magnetic flux path, or as a magnetic material for adjusting magnetic resistance, the magnetic resistance decreases as the temperature rises. Even if the temperature of the magnet increases and the magnetomotive force decreases as the microwave tube operates, the magnetic flux density in the electron beam path can be automatically kept constant.

In the embodiment shown in FIG. 7, a non-magnetic ferrule 23 is fixed to the center of a partition disk 14 made of a magnetic material, and a cylindrical permanent magnet 17.17 is fitted on the outer periphery of this ferrule 23. It is.

Since this device also has a permanent magnet placed at the ferrule, it is possible to obtain the same effect as the above-mentioned embodiment.

As described above, in the microwave tube device of the present invention, the permanent magnet is placed at the ferrule of the cavity resonator constituting the slow wave circuit, so the efficiency of magnetic flux utilization is high, and the device can be made significantly smaller. , it can be made lighter.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of a main part showing an embodiment of the present invention, FIG. 2 is a cross-sectional view taken at 2-2 in FIG. 1, and FIGS.
The figures are longitudinal sectional views of main parts showing other embodiments of the present invention. e...Electron beam, 12...Cavity resonator, 13...
・Cavity outer peripheral wall, 14... Partition disk, 17... Magnet,
18...Magnetic material for adjustment, 15...Coupling window, 21...
- Pole piece 22...conductive layer, 23...ferrule.

Claims (1)

[Claims] 1. An electron beam passage in which a plurality of cavity resonators each having a ferrule and a partition plate are arranged around an electron beam passage, and the electron beam passes through a central hole in the ferrule and partition plate. In the microwave tube device, the magnetic field generating device is provided with a magnetic field generating device for forming a periodic magnetic field for electron beam focusing in the channel, and the magnetic field generating device has the ferrule in the central through-hole of the partition plate of each cavity resonator. A microwave tube device characterized in that a cylindrical permanent magnet that also serves as a magnet is fixed coaxially around an electron beam path. 2. The microwave tube device according to claim 1, wherein the magnetic field generating device is such that the permanent magnet has a conductive layer formed on its outer surface made of a material having higher conductivity than the magnetic material. 3. A plurality of cavity resonators each having a ferrule and a partition plate are arranged around an electron beam path, and an electron beam is focused on the electron beam passage through which the electron beam passes through a central hole in the ferrule and partition plate. In the microwave tube device, the magnetic field generating device includes a partition plate of each cavity resonator formed of a magnetic material, and a center of the partition plate. A cylindrical permanent magnet that also serves as a ferrule is fixed coaxially around the electron beam path in the through-hole part, and a magnetic body that adjusts magnetic resistance is magnetically connected to the external magnetic flux path of the adjacent partition plate. A microwave tube device characterized by: 4. The microwave tube device according to claim 3, wherein the magnetic body is made of a magnetically shunt material whose magnetic resistance decreases as the temperature rises.