Gyrotron

Abstract

This suppresses the decrease in the output efficiency of the gyrotron. [Solution] The gyrotron 10 comprises a cavity resonator 16 that interacts with an electron beam 28 to generate electromagnetic waves 30, a collector 26 into which the electron beam 28 that has passed through the cavity resonator 16 is incident, a main body container 40 having an output window 24 located between the cavity resonator 16 and the collector 26, an output mirror 22 (or first mirror) disposed inside the main body container 40 that reflects the electromagnetic waves 30 toward the output window 24, a transmission mirror 20 (or second mirror) disposed inside the main body container 40 that reflects the electromagnetic waves toward the output mirror 22, and a shield 42 disposed inside the main body container 40 that extends cylindrically in the direction of propagation of the electron beam 28 on the outer periphery of a range including the region through which the electron beam 28 passes and the transmission mirror 20, and has the same potential as the transmission mirror 20.

Description

Technical Field

[0001] The present disclosure relates to a gyrotron.

Background Art

[0002] As a means for heating plasma in a fusion reactor, the use of a gyrotron that outputs electromagnetic waves such as millimeter waves and microwaves has been considered. The gyrotron causes an electron beam emitted from an electron gun to perform a spiral motion by a magnetic field, and converts the energy of the electron's swirling motion into electromagnetic waves by a cavity resonator and extracts it. The electromagnetic waves generated in the cavity resonator are taken out to the outside through a mode converter and a mirror. The electron beam that has passed through the cavity resonator is captured by a collector. In order to reduce the heat load on the collector and recover the power of the electron beam to improve efficiency, a deceleration voltage may be applied between the main body that houses the cavity resonator and the collector.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When there is a potential difference between the main body of the gyrotron and the collector, an electric field is generated between the member housed in the main body and the collector. When this electric field has a component orthogonal to the magnetic field, so-called E×B drift occurs, in which the turning center of the spiraling electrons drifts. When the electron beam drifts and the electron beam hits a member other than the collector, it causes loss and becomes a factor that reduces the output efficiency of the gyrotron.

[0005] The present disclosure has been made in view of such a situation, and an object thereof is to provide a technique for suppressing a decrease in the output efficiency of a gyrotron.

Means for Solving the Problems

[0006] A gyrotron in one aspect of the present disclosure includes: a cavity resonator that interacts with an electron beam to generate electromagnetic waves; a collector into which the electron beam that has passed through the cavity resonator is incident; a main body container having an output window located between the cavity resonator and the collector; an output mirror disposed inside the main body container and reflecting electromagnetic waves toward the output window; a transmission mirror disposed inside the main body container and transmitting electromagnetic waves toward the output mirror; and a shield disposed inside the main body container, extending cylindrically in the direction of electron beam propagation on the outer periphery of a region including the area through which the electron beam passes and the transmission mirror, and having the same potential as the transmission mirror. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic cross-sectional view showing the configuration of a gyrotron according to an embodiment. [Figure 2] This is a schematic cross-sectional view showing the configuration of a gyrotron according to an embodiment. [Figure 3] This figure schematically shows the E×B drift of electrons occurring in a gyrotron related to a comparative example. [Figure 4] This is a schematic cross-sectional view showing the configuration of a gyrotron according to another embodiment. [Modes for carrying out the invention]

[0008] The embodiments for carrying out the present invention will be described in detail below. The configurations described below are illustrative and do not limit the scope of the present invention in any way. Furthermore, the same elements are denoted by the same reference numerals in the drawings, and redundant explanations are omitted as appropriate. Also, the sizes and thicknesses of the components in the drawings referenced in the following description are for illustrative purposes only and do not necessarily represent actual dimensions or proportions.

[0009] Figure 1 is a schematic cross-sectional view showing the configuration of a gyrotron 10 according to an embodiment. The gyrotron 10 comprises an electron gun 12, a beam tunnel 14, a cavity resonator 16, a mode converter 18, a transmission mirror 20, an output mirror 22, an output window 24, and a collector 26.

[0010] In this specification, the side closer to the electron gun 12 and the side closer to the collector 26 may be referred to as the upstream side and the downstream side, respectively, with reference to the direction of propagation of the electron beam 28 from the electron gun 12 toward the collector 26. The direction toward the collector 26 from the electron gun 12 may be referred to as the axial direction. The direction of propagation of the electron beam 28 is approximately along the axial direction.

[0011] The electron gun 12 generates an electron beam 28. The electron gun 12 is, for example, a magnetron injection electron gun (MIG) and generates, for example, a cylindrical electron beam or a hollow swirling electron beam. The electron gun 12 is connected to a main power supply 32, to which a negative voltage is applied. The applied voltage of the main power supply 32 is not particularly limited, but is, for example, -10kV to -100kV.

[0012] The beam tunnel 14 is located downstream of the electron gun 12. The beam tunnel 14 guides the electron beam 28 emitted from the electron gun 12 to the cavity resonator 16. The beam tunnel 14 has a tapered shape, with its aperture diameter gradually decreasing towards the cavity resonator 16. The beam tunnel 14 is connected to a body power supply 34, which applies a positive voltage, the body potential. The applied voltage of the body power supply 34 is not particularly limited, but is, for example, +10kV to +50kV. The electron beam 28 emitted from the electron gun 12 is accelerated by the potential difference between the electron gun 12 and the beam tunnel 14.

[0013] The cavity resonator 16 is located downstream of the beam tunnel 14. The cavity resonator 16 interacts with the electron beam 28 passing through it to generate electromagnetic waves 30. An axial magnetic field, indicated by arrow Z, is applied to the cavity resonator 16 by a magnetic device 36 such as a superconducting magnet. The electron beam 28 passing through the cavity resonator 16 undergoes helical motion, wrapping around the axial magnetic field. The swirling kinetic energy of the electron beam 28 is converted into electromagnetic waves 30, such as millimeter waves or microwaves, in the cavity resonator 16 by the cyclotron resonance maser effect. The cavity resonator 16 has a body potential.

[0014] The mode converter 18 is located downstream of the cavity resonator 16. The mode converter 18 separates the electron beam 28 passing through the cavity resonator 16 from the electromagnetic wave 30 generated in the cavity resonator 16. The mode converter 18 is, for example, a Vlasov-type radiator and has an exit end that is helical or obliquely cut to have a shape corresponding to the propagation mode of the electromagnetic wave 30. The electromagnetic wave 30 emitted from the mode converter 18 is, for example, emitted obliquely with respect to the axial direction and heads toward the transmission mirror 20. The electron beam 28 passing through the mode converter 18 propagates in the axial direction. The mode converter 18 has a body potential.

[0015] The transmission mirror 20 is located downstream of the mode converter 18. The transmission mirror 20 transmits electromagnetic waves 30 from the cavity resonator 16 toward the output mirror 22. The transmission mirror 20 shapes the electromagnetic waves 30 emitted from the mode converter 18 into quasi-optical modes and transmits them. The transmission mirror 20 has a body potential.

[0016] The transmission mirror 20 may include multiple mirrors, for example, a first transmission mirror 20a facing the mode converter 18 and a second transmission mirror 20b facing the output mirror 22. The first transmission mirror 20a is, for example, a parabolic cylindrical mirror. The second transmission mirror 20b is, for example, a plane mirror. The transmission mirror 20 may include three or more mirrors, and may include an additional mirror positioned between the first transmission mirror 20a and the second transmission mirror 20b.

[0017] The output mirror 22 is located on the downstream side of the transmission mirror 20. The output mirror 22 reflects the electromagnetic wave 30 from the transmission mirror 20 toward the output window 24. The output mirror 22 is, for example, a parabolic cylinder mirror. The output mirror 22 can be provided with a drive mechanism (not shown) for making the orientation of the output mirror 22 variable in order to adjust the deviation of the optical axis of the electromagnetic wave 30 toward the output window 24. The output mirror 22 is arranged, for example, such that the electromagnetic wave 30 emitted from the output mirror 22 travels in a direction orthogonal to the axial direction. The output mirror 22 has a ground potential.

[0018] The output window 24 transmits the electromagnetic wave 30 from the output mirror 22 to the outside. The output window 24 is composed of a material that transmits the electromagnetic wave 30 and is made of, for example, alumina, sapphire, diamond, or the like. In FIG. 1, the case where only one output window 24 is provided in the output direction of the electromagnetic wave 30 is shown, but the output window 24 may be constituted by a combination of two or more window members having different thicknesses.

[0019] The collector 26 is located on the downstream side of the output mirror 22 and the output window 24. The collector 26 captures the electron beam 28 that has passed through the cavity resonator 16. The collector 26 has a shape that extends cylindrically in the axial direction. The collector 26 has, for example, a ground potential and a negative potential with respect to the cavity resonator 16. Therefore, the electron beam 28 traveling from the cavity resonator 16 toward the collector 26 is decelerated by the potential difference between the cavity resonator 16 and the collector 26. A cooling tank 38 for cooling the collector 26 heated by the incidence of the electron beam 28 is provided outside the collector 26.

[0020] The gyrotron 10 further includes a main body container 40. The main body container 40 functions as a part of a vacuum container for maintaining the region through which the electron beam 28 passes in a vacuum. The main body container 40 is located between the electron gun 12 and the collector 26 and has the output window 24. The main body container 40 can include an upstream container 40a and a downstream container 40b.

[0021] The upstream container 40a is a portion that extends cylindrically in the axial direction outside the cavity resonator 16. Inside the upstream container 40a, the beam tunnel 14, the cavity resonator 16, and the mode converter 18 are arranged. The upstream container 40a may accommodate at least a part of the transmission mirror 20. For example, the upstream container 40a may accommodate at least a part of the first transmission mirror 20a.

[0022] The downstream container 40b is a portion having a larger inner diameter than the upstream container 40a. The downstream container 40b has an output window 24. Inside the downstream container 40b, the transmission mirror 20 and the output mirror 22 are arranged. A collector 26 is attached to the downstream side of the downstream container 40b. The downstream container 40b may accommodate only a part of the transmission mirror 20. The downstream container 40b may accommodate the second transmission mirror 20b. The downstream container 40b may accommodate a part of the first transmission mirror 20a.

[0023] The main body container 40 has a ground potential. By having the main body container 40 at the ground potential, there is no need to consider the potential difference between the main body container 40 and the support structure for supporting the main body container 40 from the outside. The collector 26 can have the same potential as the main body container 40 and can have a ground potential.

[0024] The gyrotron 10 further includes a shield 42. The shield 42 is arranged inside the main body container 40 and extends cylindrically in the axial direction. The shield 42 is connected to the body power supply 34 and has a positive body potential with respect to the main body container 40. Therefore, the shield 42 has a potential different from that of the main body container 40.

[0025] The shield 42 is positioned on the outer periphery of a component having a body potential. In other words, the shield 42 is positioned between the main body container 40 and a component having a body potential different from that of the main body container 40. The shield 42 is made of a conductive material, for example, a metallic material such as copper. The shield 42 has the function of shielding the electric field so that the electric field caused by the potential difference with the main body container 40 does not act on the electron beam 28. The component having a body potential is at least one of the beam tunnel 14, cavity resonator 16, mode converter 18, and transmission mirror 20.

[0026] The shield 42 may have an upstream shield portion 42a, a downstream shield portion 42b, a connecting portion 42c, and a flange 42d.

[0027] The upstream shield section 42a is a portion located inside the upstream container 40a and has a first inner diameter d1. Inside the upstream shield section 42a are the beam tunnel 14, cavity resonator 16, mode converter 18, and first transmission mirror 20a. The second transmission mirror 20b is located outside the upstream shield section 42a.

[0028] The downstream shield portion 42b is a part located inside the downstream container 40b and has a second inner diameter d2 that is larger than the first inner diameter d1. The second transmission mirror 20b is located inside the downstream shield portion 42b.

[0029] The connecting portion 42c is the part that connects the upstream shield portion 42a and the downstream shield portion 42b. The connecting portion 42c is, for example, a ring-shaped member that extends radially perpendicular to the axial direction from the downstream end of the upstream shield portion 42a toward the upstream end of the downstream shield portion 42b.

[0030] The flange 42d is the portion that extends radially outward from the upstream shield portion 42a. The flange 42d is located between the electron gun 12 and the beam tunnel 14. The flange 42d is located downstream of the electron gun 12 and upstream of the beam tunnel 14.

[0031] The downstream end 42e of the shield 42 is located downstream of the components to which the body potential is applied. For example, the downstream end 42e of the shield 42 is located downstream of the transmission mirror 20 (e.g., the second transmission mirror 20b). The downstream end 42e of the shield 42 is located upstream of the components that have ground potential. For example, the downstream end 42e of the shield 42 is located upstream of the output mirror 22.

[0032] A notch (not shown) may be provided in a portion of the downstream end 42e of the shield 42. The notch provided in the downstream end 42e of the shield 42 can be, for example, provided at a position where the electromagnetic wave 30 traveling from the transmission mirror 20 (e.g., the second transmission mirror 20b) toward the output mirror 22 intersects with the shield 42.

[0033] The shield 42 also functions as a support structure that supports components having a body potential within the main body container 40. At least one of the beam tunnel 14, cavity resonator 16, mode converter 18, and transmission mirror 20, which have a body potential, can be fixed to and supported by the shield 42.

[0034] The gyrotron 10 further comprises at least one insulating member positioned between the main body container 40 and the shield 42. The shield 42 can be fixed to the main body container 40 via at least one insulating member. The gyrotron 10 may comprise, for example, at least one of a first insulating member 44a, a second insulating member 44b, and a third insulating member 44c.

[0035] The first insulating member 44a is positioned between the upstream end 40c of the main container 40 and the flange 42d of the shield 42. The first insulating member 44a is sandwiched axially between the main container 40 and the shield 42. The first insulating member 44a functions as a so-called DC break. The second insulating member 44b is positioned between the inner circumferential surface of the upstream container 40a and the outer circumferential surface of the upstream shield portion 42a. The second insulating member 44b is sandwiched radially between the main container 40 and the shield 42. The third insulating member 44c is positioned between the inner surface of the downstream container 40b and the connection portion 42c. The third insulating member 44c is sandwiched axially between the main container 40 and the shield 42.

[0036] The electron gun 12 can be fixed to the shield 42 via an insulating member 46. The insulating member 46 supporting the electron gun 12 can be attached to the upstream end 42f of the shield 42. The upstream end 42f of the shield 42 is located upstream of the upstream end 40c of the main body container 40 and is exposed to the outside of the main body container 40.

[0037] The gyrotron 10 may further include an electromagnetic wave absorber 48 positioned between the main body container 40 and the shield 42. The electromagnetic wave absorber 48 is positioned between the downstream container 40b and the downstream shield section 42b. The electromagnetic wave absorber 48 is configured in a cylindrical shape on the outer circumference of the downstream shield section 42b. The electromagnetic wave absorber 48 can be attached to the inner surface of the main body container 40. The electromagnetic wave absorber 48 may also be attached to the outer surface of the shield 42.

[0038] Figure 2 is a cross-sectional view of the gyrotron 10 according to the embodiment, viewed in the axial direction, and shows the AA cross-sectional view of Figure 1. The region 50 shown by the dashed line in the center of Figure 2 is the region through which the electron beam 28 passes toward the collector 26. The electron beam 28 mainly passes near the boundary of region 50, that is, along the circumference shown by the dashed line. The shield 42 is positioned to surround the outer periphery of the area including the region 50 through which the electron beam 28 passes and the transmission mirror 20. Since the shield 42 has the same potential as the transmission mirror 20, the potential inside the shield 42 can be kept constant. As a result, an electric field with a component perpendicular to the axial direction can not be generated inside the shield 42. As a result, electrons traveling inside the shield 42, as indicated by reference numeral 52, rotate to wrap around the magnetic field B applied axially by the magnet device 36, and almost no drift occurs in the direction perpendicular to the axial direction. As a result, most of the electron beam 28 travels inside the region 50 through which the electron beam 28 is designed to pass.

[0039] Figure 3 schematically shows the E×B drift of electrons occurring in the gyrotron 10A according to the comparative example. The comparative example differs from the embodiment described above in that a shield 42 is not placed inside the main body container 40. In the comparative example, because there is no shield 42, there is an electric field E that flows from the transmission mirror 20, which has a positive body potential, to the main body container 40, which has a ground potential. Since the electric field E is perpendicular to the axial magnetic field B, an E×B drift occurs in electrons traveling inside the shield 42. As a result, electrons traveling inside the shield 42 drift in the direction along the reflective surface 56 of the transmission mirror 20, as indicated by reference numeral 54. If the amount of drift is large, electrons deviate outside the region 50 through which the electron beam 28 is designed to pass.

[0040] Inside the gyrotron 10A, there are not only electrons traveling downstream from the electron gun 12 towards the collector 26, but also electrons reflected by the collector 26 and traveling upstream. When electrons traveling upstream drift and deviate outside the region 50, they enter components with body potential (e.g., the beam tunnel 14, the cavity resonator 16, the mode converter 18, or the transmission mirror 20), leading to an increase in body current. An increase in body current means an increase in electrons that are not captured by the collector 26 and are lost, reducing the efficiency of the gyrotron 10A.

[0041] Furthermore, while the body power supply 34 can output high voltage, it is often a power supply with a low rated current. If drifting electrons enter unintended locations and increase the body current, it will exceed the rating of the body power supply 34, making operation impossible, and thus the output of the gyrotron 10A must be reduced. Moreover, adopting a power supply with a higher rated current would lead to a significant increase in equipment size and cost, as well as a decrease in efficiency.

[0042] According to this embodiment, since the shield 42 is placed between the main body container 40 and the transmission mirror 20, drift of the electron beam 28 passing near the transmission mirror 20 can be prevented or suppressed. As a result, the proportion of the electron beam 28 that is lost without entering the collector 26 can be suppressed, and the output efficiency of the gyrotron 10 can be improved.

[0043] According to this embodiment, the entire main container 40 is at ground potential, eliminating the need to consider insulation between the main container 40 and the support structure for supporting it. For example, the main container 40 can be directly fixed to the upper surface of the magnet device 36 by a flange 40d provided on the main container 40.

[0044] According to this embodiment, since the main body container 40 and the collector 26 have the same potential, there is no need to provide an insulating member called a DC break between the main body container 40 and the collector 26. Therefore, the axial size of the downstream container 40b that houses the transmission mirror 20 and the output mirror 22 can be reduced, and the axial size of the entire gyrotron 10 device can be suppressed. For example, it becomes possible to increase the axial length of the collector 26 in order to increase the output power while maintaining the axial size of the entire gyrotron 10 device.

[0045] Figure 4 is a schematic cross-sectional view showing the configuration of a gyrotron 60 according to another embodiment. Hereinafter, the gyrotron 60 according to this other embodiment will be described, focusing on the differences from the embodiment shown in Figure 1, while the similarities will be omitted as appropriate.

[0046] The gyrotron 60 comprises an electron gun 12, a beam tunnel 14, a cavity resonator 16, a mode converter 18, a transmission mirror 20, an output mirror 22, an output window 24, and a collector 26. The gyrotron 60 may further include a main power supply 32, a body power supply 34, a magnet device 36, and a cooling tank 38. These are the same as those in the embodiment shown in Figure 1 above.

[0047] The transmission mirror 20 may include a third transmission mirror 20c in addition to the first transmission mirror 20a and the second transmission mirror 20b. The third transmission mirror 20c is located between the first transmission mirror 20a and the second transmission mirror 20b and reflects the electromagnetic waves reflected by the first transmission mirror 20a toward the second transmission mirror 20b. The third transmission mirror 20c is, for example, a plane mirror.

[0048] The gyrotron 60 further comprises a main body container 62, a body container 64, and an insulating member 66. The main body container 62, the body container 64, and the insulating member 66 function as vacuum vessels for maintaining a vacuum in the region through which the electron beam 28 passes.

[0049] The main body casing 62 is located between the transmission mirror 20 and the collector 26 and has an output window 24. The main body casing 62 houses the output mirror 22. The main body casing 62 has ground potential. The body casing 64 is located between the electron gun 12 and the transmission mirror 20 and houses the beam tunnel 14, cavity resonator 16, and mode converter 18. The body casing 64 has body potential due to the body power supply 34. The insulating member 66 is located between the main body casing 62 and the body casing 64 and extends cylindrically to connect them. The insulating member 66 is a DC break for electrically insulating the main body casing 62 and the body casing 64. The insulating member 66 is located, for example, on the outer circumference of the transmission mirror 20.

[0050] The gyrotron 60 further comprises a shield 68. The shield 68 is located at least inside the main body casing 62 and extends axially in a cylindrical shape. The shield 68 is attached to the body casing 64 and has the same body potential as the body casing 64. The shield 68 can be located between the transmission mirror 20 and the insulating member 66.

[0051] The shield 68 has an upstream end 68a and a downstream end 68b. The upstream end 68a of the shield 68 is attached to a component to which the body potential is applied, for example, to the body container 64. The downstream end 68e of the shield 68 is located downstream of the component to which the body potential is applied. For example, the downstream end 68e of the shield 68 is located downstream of the transmission mirror 20 (for example, the second transmission mirror 20b). The downstream end 68e of the shield 68 is located upstream of the component that has the ground potential. For example, the downstream end 68e of the shield 68 is located upstream of the output mirror 22.

[0052] A notch (not shown) may be provided in a portion of the downstream end 68e of the shield 68. The notch provided in the downstream end 68e of the shield 68 can be provided, for example, at a position where the electromagnetic wave 30 traveling from the transmission mirror 20 (e.g., the second transmission mirror 20b) toward the output mirror 22 intersects with the shield 68.

[0053] The shield 68 can achieve the same effects as the shield 42 in the embodiment shown in Figure 1. Similar to the shield 42 shown in Figure 2, the shield 68 is positioned to surround the outer periphery of the area including the region 50 through which the electron beam 28 passes and the transmission mirror 20. By positioning such a shield 68, drift of the electron beam 28 passing near the transmission mirror 20 can be prevented or suppressed. As a result, the proportion of the electron beam 28 that is lost without entering the collector 26 can be suppressed, and the output efficiency of the gyrotron 60 can be improved.

[0054] The present disclosure has been described above based on embodiments. Various modifications are possible for each component and each combination of processes in the exemplary embodiments, and it will be obvious to those skilled in the art that such modifications are included in the scope of the present disclosure. [Explanation of symbols]

[0055] 10...Gyrotron, 12...Electron gun, 16...Cavity resonator, 20...Transmission mirror, 20a...First transmission mirror, 20b...Second transmission mirror, 22...Output mirror, 24...Output window, 26...Collector, 28...Electron beam, 30...Electromagnetic wave, 40...Main container, 42...Shield, 42a...Upstream shield section, 42b...Downstream shield section, 42c...Connection section, 44a...First insulating member, 44b...Second insulating member, 44c...Third insulating member, 46...Insulating member, 48...Electromagnetic wave absorber.

Claims

1. A cavity resonator that interacts with an electron beam to generate electromagnetic waves, A collector that captures the electron beam that has passed through the cavity resonator, A main body container having a window located between the cavity resonator and the collector, A first mirror is placed inside the main body container and reflects electromagnetic waves toward the window, A second mirror is placed inside the main body container and reflects electromagnetic waves toward the first mirror, The shield is disposed inside the main body container and extends cylindrically in the direction of electron beam propagation on the outer circumference of the area including the region through which the electron beam passes and the second mirror, and has the same potential as the second mirror. Gyrotron.

2. The end of the shield is located downstream of the second mirror in the direction of electron beam propagation. The gyrotron according to claim 1.

3. The end of the shield is located upstream of the first mirror in the direction of electron beam propagation. The gyrotron according to claim 2.

4. The shield has a different potential from the main container. A gyrotron according to any one of claims 1 to 3.

5. The system further comprises an insulating member disposed between the main body container and the shield. The gyrotron according to claim 4.

6. The system further comprises an electromagnetic wave absorber positioned between the main body container and the shield. The gyrotron according to claim 5.

7. The shield comprises an upstream shield portion, a downstream shield portion having a larger inner diameter than the upstream shield portion, and a connecting portion connecting the upstream shield portion and the downstream shield portion. A gyrotron according to any one of claims 1 to 3.

8. The second mirror is positioned outside the upstream shield portion and inside the downstream shield portion. The gyrotron according to claim 7.

9. The system further comprises a third mirror positioned inside the upstream shield section and reflecting electromagnetic waves toward the second mirror. The gyrotron according to claim 8.

10. The system further comprises an insulating member disposed between the main body container and the connection portion of the shield. The gyrotron according to claim 7.

11. The main body container has a portion that extends cylindrically in the direction of electron beam propagation on the outer circumference of the cavity resonator, The shield has a portion that extends cylindrically in the direction of the electron beam's propagation between the inner surface of the main body container and the cavity resonator. A gyrotron according to any one of claims 1 to 3.

12. The system further comprises an insulating member positioned between the main body container and the shield, and located upstream of the cavity resonator in the direction of electron beam propagation. The gyrotron according to claim 11.

13. A body container housing the aforementioned cavity resonator, The system further comprises an insulating member connecting the main body container and the body container, The shield is attached to the body container and positioned between the second mirror and the insulating member. A gyrotron according to any one of claims 1 to 3.

14. The system further comprises an electron gun that emits the electron beam toward the aforementioned cavity resonator, The electron gun is fixed to the shield via an insulating member. A gyrotron according to any one of claims 1 to 3.

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