JP2570168Y2 - Gyrotron device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gyrotron device, and more particularly, to an improvement in a ferromagnetic cylinder disposed around a collector.

[0002]

2. Description of the Related Art As is well known, a gyrotron device is an electron tube whose operation principle is a cyclotron mesas, and is used as a high-frequency high-power source in the millimeter wave to submillimeter wave band.

[0003] Such a gyrotron device has an electron gun section for generating a hollow electron beam, and a tapered electron beam introduction section which is arranged downstream of the electron gun section and has a gradually decreasing diameter. A resonant cavity provided downstream of the tapered electron beam introduction portion and interacting with the helically moving electron beam; and a gradually increasing diameter provided downstream of the resonant cavity. A tapered guide portion, a cylindrical collector portion disposed downstream of the tapered guide portion for capturing the electron beam after the interaction, and a device for taking out the electromagnetic waves to the outside and also providing the inside of the tube. It comprises an output window having a dielectric electromagnetic wave transmission window hermetically sealed so as to maintain a vacuum, a magnet for giving a helical motion to the hollow electron beam, and the like.

In operation, downstream of the resonant cavity,
The electron beam is diffused mainly by the action of a magnetic field that decreases from the resonant cavity toward the collector, is captured by the inner wall surface of the collector, and converts kinetic energy to heat energy (heat loss). . At the same time, the oscillating high-frequency output propagates through the collector, passes through the output window, and is taken out.

By the way, in order to form a magnetic field component crossing the tube axis of the gyrotron device in the collector so that the electron beam collides with the collector in parallel, a magnet is placed near the entrance of the collector. Those arranged (Japanese Unexamined Patent Publication No.
No.-27035) or a ferromagnetic cylinder disposed around a collector (Japanese Utility Model Laid-Open No. 2-1485).
No. 51).

[0006]

The above conventional gyrotron apparatus has the following disadvantages.

That is, in the gyrotron device, the electron beam
The electron orbit is determined mainly by the lines of magnetic force because electrons orbit around the lines of magnetic force. Since the flatness of the magnetic field in the resonance cavity is required to stabilize the oscillation, the main magnetic field magnet needs to have a certain length in the axial direction.

For this reason, when the total length of the gyrotron device is limited, the magnetic field does not become sufficiently weak at the collector portion, and the electron beam reaches the airtight window of the output portion without sufficiently diverging. As a result, the hermetic window is heated and may be damaged by discharge due to charge-up. Placing a ferromagnetic cylinder around the collector to prevent this is known as described above, but if the magnetic field is shielded by a ferromagnetic cylinder of uniform thickness, the collector There is the disadvantage that only a part of the part is heated.

This invention has been made in view of the above circumstances, and the used electron beam is made to enter a wider area of the inner wall of the collector to reduce the heat load of the collector and to output a large power. It is an object of the present invention to provide a gyrotron device capable of performing the following.

[0010]

The present invention is a gyrotron device in which a ferromagnetic cylinder disposed around a collector section has a gradually decreasing magnetic permeability as it goes downstream of the beam.

[0011]

According to this invention, the magnetic permeability gradually decreases as the ferromagnetic cylinder goes downstream of the beam.
Lines of magnetic force are diffused near the end of the tapered guide portion and near the entrance of the collector portion, and electrons are trapped on the inner wall of the collector from this vicinity. The ferromagnetic cylinder becomes thinner as the main magnetic field decreases toward the downstream of the beam, so that the magnetic flux density becomes almost uniform up to the middle of the collector portion, and the diffusion of electrons is somewhat suppressed. Further, by selecting the thickness of the ferromagnetic cylinder so that the magnetic flux density decreases as the main magnetic field decreases toward the end of the collector, the electron beam incident range in the collector can be expanded, and the local area can be reduced. A small gyrotron device with a large output can be obtained.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

The gyrotron device according to the present invention is configured as shown in FIG. 1, and reference numeral 1 in the figure denotes an electron gun for generating an electron beam. Downstream of the electron beam from the electron gun section 1, a tapered electron beam introduction section 2 having a gradually decreasing diameter is arranged. Downstream of the electron beam introduction section 2, a resonance cavity is provided. The part 3 is provided continuously. Downstream of the resonant cavity 3, a tapered guide 4 having a gradually increasing diameter for guiding the electromagnetic wave and the electron beam 11 is continuously provided.

Further, downstream of the tapered guide portion 4,
A cylindrical collector portion 5 is disposed, and an output window portion 6 having a ceramic airtight window 12 is provided downstream of the collector portion 5.
Is arranged. A magnetic field generator (cryostat) 8 including an external magnet 7 is disposed outside from the electron gun 1 to the tapered guide 4, and applies a predetermined main magnetic field to the resonance cavity 3. . The tapered guide 4, the collector 5 and the output window 6 are made of circular waveguides.
Is a waveguide separating portion having a gap.

Further, in the present invention, the ferromagnetic cylinder 13 is disposed around the collector 5 and the ferromagnetic cylinder 13
Is gradually reduced in thickness as it goes downstream of the beam. In this embodiment, the ferromagnetic cylinder 13 is tapered in the downstream direction of the beam. Thereby, the magnetic permeability of the ferromagnetic cylinder 13 is large on the upstream side of the beam, and gradually decreases toward the downstream side of the beam.

In operation, the electron beam 11 emitted from the electron gun unit 1 is rotated by a main magnetic field generated by the external magnet 7 and an electric field applied between the anode and the cathode, having a cyclotron frequency. Start exercising. Due to the adiabatic compression effect of the mirror magnetic field that gradually increases from the electron gun 1 toward the resonance cavity 3, the light enters the resonance cavity 3 while increasing the turning motion. Interacts with the excited high-frequency electromagnetic field in the resonant cavity 3,
The energy of the electrons is converted to high frequency energy. The electron beam that has completed the interaction in the resonance cavity 3 collides with the inner wall surface of the collector 5 guided by the external magnetic field, and is converted into heat. The high frequency generated in the resonance cavity 3 is guided to an external circuit through the output window 6.

By the way, in this invention, since the ferromagnetic cylinder 13 formed in the shape of a tape in the downstream direction of the beam is arranged around the collector section 5, FIGS. 2 (a) and 2 (b) show. As shown, near the downstream end of the tapered guide portion 4 and near the upstream end of the collector portion 5, the magnetic flux density distribution temporarily decreases, and the electron beam is diffused and starts to be captured by the inner wall of the collector portion 5. On the downstream side of the beam, the thickness of the ferromagnetic cylinder 13 is reduced, so that the magnetic flux density distribution does not decrease so much and is kept substantially constant. Go. This makes it possible to capture the electron beam over a wide range of the collector section 5 without affecting the main magnetic field of the resonant cavity 3. Also, the collector part 5
The magnetic field on the upstream side of the electron beam can be sufficiently weakened, and the electron beam can be reliably captured by the collector section 5.

As a result, the local thermal load on the collector section 5 is reduced, and the electron beam is dispersed and can be captured by the collector section 5, so that the electron beam reaches the ceramic hermetic window 12. It is possible to prevent the battery from being locally heated, charged up, discharged, and damaged.

FIG. 3 shows another embodiment of the present invention, and the same effects as in the above embodiment can be obtained. That is, although the ferromagnetic cylinder 13 of the above embodiment was tapered, FIG.
The cross section of the ferromagnetic cylinder 14 shown in FIG. 1 is gradually reduced as it goes down the beam in a stepped shape.

Further, the ferromagnetic cylinder may be constituted by arranging a plurality of cylinders made of a material whose relative permeability is sequentially smaller from the upstream side of the beam. Thus, the beam is higher than the beam upstream side.
The downstream side of the system may be configured as a ferromagnetic cylinder having a gradually smaller magnetic permeability.

[0021]

According to the present invention, the ferromagnetic cylinder disposed around the collector gradually decreases in magnetic permeability as it goes downstream of the beam, so that electrons can flow near the entrance of the collector. Is reliably captured from The spread of electrons is slightly suppressed near the middle of the collector, and the magnetic flux density is sufficiently weakened at the downstream end of the collector. As described above, the gyrotron device capable of outputting a large amount of power can be obtained because the collector portion can be reliably captured over a wide range of the collector portion.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a gyrotron device according to an embodiment of the present invention.

FIG. 2 is a characteristic curve diagram and a vertical sectional view of a main part showing a relationship between a magnetic flux density distribution and a position of a ferromagnetic cylinder in the gyrotron device of the present invention and a conventional gyrotron device.

FIG. 3 is a longitudinal sectional view showing a gyrotron device according to another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electron gun part, 2 ... Electron beam introduction part, 3 ... Resonance cavity part, 4 ... Tape-shaped guide part, 5 ... Collector part, 6 ... Output window part, 13,14 ... Ferromagnetic cylinder .

Claims (1)

(57) [Scope of request for utility model registration] An electron gun for generating a hollow electron beam;
A tape that is located downstream of this electron gun and has a gradually decreasing diameter
A beam-shaped electron beam introduction part, a resonant cavity provided downstream of the tapered electron beam introduction part, and a taper having a gradually increasing diameter provided downstream of the resonance cavity. A cylindrical guide portion disposed downstream of the tapered guide portion, the tapered guide portion, and a ferromagnetic cylinder disposed around the collector portion;
A magnetic field generating device disposed outside from the electron gun section to the tapered guide section, wherein the ferromagnetic cylinder is arranged at a position higher than the beam upstream side. A gyrotron device wherein the magnetic permeability gradually decreases toward the downstream of the beam.