JPH01276541A - gyrotron device - Google Patents

Abstract

PURPOSE:To reduce the heat flux applied to a collector by generating the magnetic field in the opposite direction to the main magnetic field of a resonant cavity section on a solenoid near the resonant cavity section and generating the magnetic field in the same direction as the main magnetic field of the resonant cavity section on a solenoid near an output window section. CONSTITUTION:Solenoids 9-11 of an auxiliary magnetic field device are arranged on the outside of a tapered guide section 4 and a collector section 5, the solenoid 9 generating the magnetic field in the opposite direction to the main magnetic field of a resonant cavity section 3 is arranged in the most upstream direction of an electron beam, the solenoids 10 and 11 generating the magnetic field in the same direction as the main magnetic field are arranged at the downstream from it. The magnetic flux density distribution is once largely decreased near the downstream end of the tapered guide section 4 and near the upstream end of the collector section 5, the magnetic flux density distribution is increased at the downstream on the contrary, thereby the electron beam 12 can be captured by the collector section 5 over a wide range without giving any effect to the main magnetic field of the resonant cavity section 3. The local heat load on the collector section 5 can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a gyrotron device, and particularly to its magnetic field generating means.

(Prior Art) As is well known, a gyrotron device 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.

Such a gyrotron device consists of an electron gun section that generates an electron beam, a resonant cavity section that interacts with the spirally moving electron beam, a collector section that captures the electron beam after the interaction, and a collector section that captures the electron beam after the interaction. A dielectric electromagnetic wave transmitting window (airtight window) which is hermetically sealed to take out the electron beam and maintain a vacuum inside the tube, and a magnet etc. which give a spiral motion to the electron beam (I) are formed.

During operation, downstream of the resonant cavity, the electron beam is mainly diffused by the magnetic field that decreases from the resonant cavity toward the collector, and is captured by the inner wall of the collector, converting kinetic energy into thermal energy. Convert to It is known to place a magnet near the entrance of the collector section in order to form a magnetic field component that crosses the tube axis of the gyrotron inside the collector section so that the electron beam collides with the collector section on average. (Japanese Unexamined Patent Publication No. 61-27035).

(Problems to be Solved by the Invention) In the conventional gyrotron device as described above, the electron beam trajectory is mainly determined by the magnetic lines of force because the electrons move in a spiral manner while being wrapped around the lines of magnetic force. In recent years, a gyrotron that uses a TEmn (m>n) mode called a whispering gear rally mode type that can output a large amount of power has been developed.

In this type of gyrotron, the electric field peak within the resonant cavity exists near the cavity wall, so the position at which the electron beam is implanted into the resonant cavity also needs to be close to the cavity wall.

Therefore, the magnetic flux density of the magnetic field at the electron beam position rapidly decreases from the resonant cavity toward the collector, heating only a portion of the collector, and there is a risk of damaging the collector.

In order to reduce the heat flux in the collector, it is effective to increase the collector diameter, but in a gyrotron, the collector also serves as the microwave output waveguide, so increasing the size requires mode conversion. Constraints from points.

An object of the present invention is to provide a gyrotron device that can eliminate the above-mentioned disadvantages, prevent electron beams from being locally incident on the collector wall, and reduce the heat flux applied to the collector. .

[Structure of the Invention] (Means for Solving the Problems) This invention provides a tapered guide section and a collector section with a
Of these solenoids, the solenoid near the resonant cavity receives a magnetic field in the opposite direction to the main magnetic field of the resonant cavity, and the solenoid near the output window receives the main magnetic field of the resonant cavity. It is a gyrotron device that generates a magnetic field in the same direction as the magnetic field (1-! configuration).

(Function) According to the present invention, the lines of magnetic force are more strongly diffused near the end of the tapered guide portion and near the sunset of the collector portion, and electrons are reliably captured by the collector wall from these areas, and furthermore, in the middle portion of the collector portion. The magnetic flux density increases in the vicinity of the downstream side, and the diffusion of electrons is somewhat suppressed, so that electrons are captured more evenly over the entire region of the collector section. In this way, the range of electron beam incidence on the collector section is further widened, local heat generation can be alleviated, and a gyrotron device with high power output can be obtained.

(Embodiment) Hereinafter, one embodiment of the present invention will be described in detail (4) with reference to the drawings.
explain.

The gyrotron device of the present invention is constructed as shown in FIG. 1, and reference numeral 1 in the figure is an electron gun section that generates a hollow electron beam. Downstream of the electron beam of this electron gun section 1,
A tapered electron beam introducing section 2 whose diameter gradually becomes smaller is arranged, and a resonant cavity section 3 is disposed downstream of this electron beam introducing section 2.
are provided continuously. A tapered guide section 4 whose diameter gradually increases is continuously provided downstream of the resonant cavity section 3 for guiding electromagnetic waves and electron beams.

Furthermore, a cylindrical collector part 5 is arranged downstream of this tapered guide part 4, and an output window part 6 having a ceramic airtight window is arranged downstream of this collector part 5. Further, a cryostat 8 consisting of an external magnet 7 is arranged outside from the electron gun section 1 to the tapered guide section 4, and applies a predetermined main magnetic field to the resonant cavity section 3.

Therefore, in the present invention, a solenoid of the auxiliary magnetic field device is arranged outside the tapered guide section 4 and the collector section 5. This solenoid consists of a combination of a solenoid that generates a magnetic field in the opposite direction to the main magnetic field by the external magnet 7 downstream of the tapered guide part 4 and near the upper end of the collector part 5, and a solenoid that generates a magnetic field in the same direction. There is.

For example, as shown in the figure, the solenoid 9 that generates a magnetic field in the opposite direction to the main magnetic field of the resonant cavity 3 is placed in the most upstream direction of the electron beam among the three solenoids, and the solenoid 9 that generates a magnetic field in the opposite direction to the main magnetic field of the resonance cavity 3 is placed downstream A solenoid 10.11 is arranged to generate a magnetic field in the same direction as the main magnetic field.

These solenoids 9.10.11 are each driven by a DC power supply, and depending on the operating conditions, the solenoid 9.1
It is possible to vary the polarity and strength of the generated magnetic field of 0.11.

In addition, a solenoid 10 that generates a magnetic field in the same direction as the main magnetic field
．． The solenoid 11 on the downstream side of the electron beam 12 generates a stronger magnetic field (magnetic flux density) than the solenoid 10 on the upstream side.

Now, during operation, the electron beam 1 emitted from the electron gun section 1
2 is the main magnetic field generated by the external magnet 7 and the anode.
The electric field applied between the cathodes causes a swirling motion with a cyclotron frequency. Due to the adiabatic compression effect of the mirror magnetic field that gradually increases from the electron gun section 1 toward the resonant cavity section 5, the electrons enter the resonant cavity section 3 while increasing the rotation speed. In the resonant cavity 3, the electrons interact with the excited high-frequency electromagnetic field, and the energy of the electrons is converted into high-frequency energy. After completing the interaction in the resonant cavity 5, the electron beam collides with the inner wall surface of the collector section 5 guided by an external magnetic field and is converted into heat. The high frequency waves generated in the resonant cavity 3 are guided to an external circuit through the output window 6.

In the above case, in this invention, the solenoids 9, 10, and 11 are disposed outside the tapered guide section 4 and the collector section 5, so that the A magnetic flux density distribution (a+) is shown that once drops significantly near the upstream end of the collector portion 5, and a magnetic flux density distribution (a2) is conversely high downstream. Thereby, the resonant cavity 3
The electron beam 12 can be captured over a wide range by the collector section 5 without having the same effect on the main magnetic field. As a result, the local heat load on the collector section 5 can be reduced. Moreover, it becomes possible to lengthen the tapered guide portion 4, and it also becomes possible to reduce mode conversion.

[Effects of the Invention] As explained above, according to the present invention, the lines of magnetic force are more strongly diffused near the end of the tapered guide section and near the entrance of the collector section, and the 7-strand beam is reliably captured on the collector wall from this vicinity. In addition, the magnetic flux density is rather increased near the middle part of the collector part and downstream thereof, and the diffusion of electrons is somewhat suppressed, so that electrons are captured more evenly over the entire area of the collector part. In this way, the range of electron beam incidence on the collector section is further widened, local heat generation can be alleviated, and a gyrotron device with high power output can be obtained.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a schematic vertical cross-sectional view showing a gyrotron device according to an embodiment of the present invention, and Fig. 2 shows magnetic flux density characteristics and solenoid positions in the gyrotron device of the present invention and the conventional gyrotron device. FIG. 2 is a characteristic curve diagram and a schematic vertical cross-sectional view of main parts showing the relationship between the two. 1... Electron gun section, 2... Electron beam introduction section, 3...
- Resonance cavity part, 4... Tapered guide part, 5... Collector part, 6... Output window part, 7... External magnet, 8...
・Cryostat, 9.10.11...Solenoid. Applicant's agent Patent attorney Takehiko Suzue

Claims (1)

[Claims] An electron gun section that generates a hollow electron beam, a tapered electron beam introduction section that is arranged downstream of the electron gun section and whose diameter gradually becomes smaller, and a tapered electron beam introduction section downstream of the tapered electron beam introduction section. A resonant cavity section provided, a tapered guide section provided downstream of the resonant cavity section whose diameter gradually increases, and a cylindrical collector section disposed downstream of the tapered guide section. In the gyrotron device, a plurality of solenoids are arranged outside the tapered guide section and the collector section, and among these solenoids, the solenoid near the resonant cavity section has a magnetic field opposite to the main magnetic field of the resonant cavity section. A gyrotron device characterized in that the solenoid near the output window generates a magnetic field in the same direction as the main magnetic field of the resonant cavity.