vacuum tubes

Abstract

An electron tube (100) comprises: a cathode (3) which emits thermoelectrons; an anode which comprises a plurality of anode pieces (4) arranged in an anode cylinder (2) inside an anode cylinder structure (1) so as to surround the cathode (3) to thereby form a cavity resonator; an input part in which a cathode lead (5) for applying an input voltage is disposed; an output part which emits microwaves to the outside; and a waveguide (W1) which transmits the microwaves. A hermetically closable shield case (9) that surrounds part of the cathode lead (5) has been bonded to an input-part-side outer surface of the anode cylinder structure (1). The waveguide (W1), which is hermetically closable, has been bonded to an output-part-side outer surface of the anode cylinder structure (1). The anode cylinder structure has a through-hole (12) having a first opening (10), which is open to the region surrounded by the shield case (9), and a second opening (11), which is open to the inside of the waveguide (W1).

Description

Technical Field

[0001] The present invention relates to an electron tube, and more particularly to an electron tube that outputs high-power microwaves.

Background Art

[0002] In order to achieve higher power in medical and non-destructive inspection Linac (linear accelerator) systems, etc., it is necessary to improve the insulation breakdown voltage of the electron tube that is the microwave oscillation source and the transmission path that transmits the microwave output from the electron tube. For example, it is necessary to improve the breakdown voltage of the input part where a high input voltage is applied in a magnetron that is the microwave oscillation source, and it is necessary to improve the breakdown voltage (high-frequency breakdown voltage against the occurrence of internal arcing in the waveguide) in the waveguide that transmits the microwave output from the magnetron.

[0003] In order to improve the breakdown voltage of the input part of the magnetron, for example, Patent Document 1 discloses a structure in which a rod-shaped conductor (corresponding to the cathode lead) to which a high voltage is applied is covered with an insulator such as silicon rubber. Also, in order to improve the breakdown voltage of the waveguide that transmits microwaves, for example, Patent Document 2 discloses a technique for maintaining the inside of the waveguide in an atmosphere such as sulfur hexafluoride (SF6) gas or a high vacuum.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] As described above, by covering the input section of the magnetron with an insulator and improving the insulation between the voltage-bearing terminals, it becomes possible to increase the input voltage to about 20kV. As a result, the output power of the electron tube can be increased to about 80kW.

[0006] However, with the demand for even higher power output from electron tubes, for example, it is required to increase the output power of magnetrons to 3 MW or more. In this case, the input voltage of the magnetron needs to be, for example, around 46 kV. Such high-power microwaves can be transmitted by filling the waveguide with pressurized dry air or highly insulating sulfur hexafluoride gas, or by maintaining a vacuum inside the waveguide. However, such high-power magnetrons cannot be covered with insulating materials such as silicone rubber due to heat conduction and heat radiation from the cathode and anode, which become hot during operation. Therefore, it is necessary to improve the voltage withstand capability of the magnetron's input section using an alternative insulating structure.

[0007] To improve the voltage withstand capability of the magnetron's input section, one might consider a structure that encloses the input section in a sealed case and fills the case with insulating oil or a highly insulating gas. However, since the input section becomes hot, there is a risk of insulating oil or gas leaking from the case due to thermal expansion, and a complex structure to absorb the pressure caused by expansion would be necessary to prevent leakage. Furthermore, a structure that fills the case with gas would require an inlet for injecting the gas, and a complex structure would be needed to maintain a pressurized state after gas injection and to detect that pressurized state, making such a structure difficult to adopt.

[0008] Therefore, the object of the present invention is to provide an electron tube that can improve the voltage withstand capability of the input section and achieve higher output power without requiring a complex structure. [Means for solving the problem]

[0009] One embodiment of the electron tube of the present invention comprises a cathode that emits thermionic electrons, an anode in which a plurality of anode pieces are arranged in an anode cylinder inside an anode cylindrical structure so as to surround the cathode and a cavity resonator is formed between the anode pieces, an input section from which a cathode lead is drawn out for applying an input voltage to the cathode, an output section that emits microwaves excited by the cavity resonator to the outside, and a waveguide that transmits microwaves emitted from the output section, wherein a sealable shield case surrounding a part of the cathode lead is joined to the outer surface of the anode cylindrical structure on the input section side, and a sealable waveguide is joined to the outer surface of the anode cylindrical structure on the output section side, and the anode cylindrical structure is configured to have a communication hole having a first opening that opens into the region surrounded by the shield case and a second opening that opens into the waveguide. [Effects of the Invention]

[0010] The electron tube of the present invention has a configuration in which a communication hole is provided with an opening in the region surrounded by a shielding case that covers a part of the cathode lead to which an input voltage is applied to the cathode, and in the waveguide that transmits microwaves emitted from the output section. As a result, the inside of the waveguide that transmits high-power microwaves and the inside of the shielding case are in communication, the voltage withstand capability of the input section is improved, and it becomes possible to provide a high-power electron tube. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic cross-sectional view of an electron tube (Embodiment 1), which is one embodiment of the present invention. [Figure 2] This is a schematic cross-sectional view of an electron tube (Embodiment 2), which is another embodiment of the present invention. [Figure 3] This is a schematic cross-sectional view of an electron tube (Embodiment 3), which is yet another embodiment of the present invention. [Figure 4] This is a schematic cross-sectional view of an electron tube (Embodiment 4), which is yet another embodiment of the present invention. [Figure 5] This is a schematic cross-sectional view of an electron tube (Embodiment 5), which is yet another embodiment of the present invention. [Figure 6] This is a partially enlarged view of the joint portion between the third hole and the second hole that constitute the communication hole in Embodiment 5. [Figure 7] This is a schematic cross-sectional view of an electron tube (Embodiment 6), which is yet another embodiment of the present invention. [Figure 8] This is a partially enlarged view of the joint portion between the fourth hole and the second hole that constitute the communication hole in Embodiment 6. [Modes for carrying out the invention]

[0012] The electron tubes of the present invention will be described with reference to the drawings, but the present invention is not limited to these forms, and the components described below can be modified in various ways within the scope of the spirit of the present invention. In addition, the same reference numerals in the drawings indicate equivalent or identical components, and the sizes and positional relationships between each component are for convenience only and do not strictly reflect the actual situation.

[0013] The electron tube of the present invention has a sealed shielding case joined to the outer surface of the anode cylindrical structure on the input side, surrounding a portion of the cathode lead that is drawn out from the anode cylindrical structure and exposed, and a sealed waveguide joined to the outer surface of the anode cylindrical structure on the output side. Furthermore, the anode cylindrical structure is configured to have a communication hole having a first opening that opens into the area surrounded by the shielding case and a second opening that opens into the waveguide.

[0014] In this configuration, the inside of the waveguide and the inside of the shielding case can be connected. For example, when the waveguide is filled with pressurized dry air, or with highly insulating sulfur hexafluoride gas, or when the waveguide is kept under vacuum to transmit high-power microwaves, the inside of the shielding case connected by the connecting hole can also be filled with pressurized dry air or sulfur hexafluoride gas, or kept under vacuum, thereby improving the voltage withstand capability of the input section and, as a result, enabling higher output power for the electron tube.

[0015] (Embodiment 1) First, Embodiment 1 of the electron tube of the present invention will be described. FIG. 1 is a schematic cross-sectional view for explaining Embodiment 1 of the electron tube of the present invention, and is a schematic cross-sectional view perpendicular to the tube axis direction of the anode cylinder. As shown in FIG. 1, the electron tube 100 of the present embodiment is configured such that a waveguide W1 is joined to the output portion of a magnetron M1. The magnetron M1, like a general magnetron, has a cylindrical anode cylinder 2 formed inside an anode cylinder structure 1, and a plurality of anode pieces 4 are arranged radially. One end of each anode piece 4 is joined to the inner wall of the anode cylinder 2, forming an anode at ground potential. A cathode 3 is arranged at the center of the radially arranged anode pieces 4. The anode piece 4 may be integrated with the anode cylinder 2, and any structure may be adopted as long as a cavity resonator is formed in the space surrounded by the anode piece and the anode cylinder 2.

[0016] A negative voltage corresponding to the anode voltage as an input voltage is applied to the cathode 3 from the cathode lead 5 drawn out to the input portion. Further, the cathode 3 is heated by a heater (not shown) and emits thermoelectrons. The cathode 3 shown in FIG. 1 is supported at both ends from a direction perpendicular to the central axis of the cathode 3 by the cathode leads 5, and two cathode leads 5 are drawn out to the input portion. The side surface of the anode cylinder structure 1 from which the cathode lead 5 is drawn out becomes the "outer surface of the anode cylinder structure on the input portion side".

[0017] Magnetic circuits (not shown) are arranged on both side surfaces of the anode cylinder structure 1 in the tube axis direction of the anode cylinder 2, and a magnetic field is formed along the axial direction of the cathode 3 in the anode cylinder 2 by these magnetic circuits. Electrons emitted from the cathode 3 having a negative voltage with respect to the anode at ground potential start a circular motion in the action space between the cathode 3 and the tip of the anode piece 4 under the action of an electric field and a magnetic field, resonate in the cavity resonator formed between the anode pieces 4, and microwaves are excited. These microwaves are output from the antenna 6 at the output portion to the waveguide W1. The antenna 6 covered with the antenna cap 7 protrudes, and the side surface of the anode cylinder structure 1 to which the waveguide W1 is joined becomes the "outer surface of the anode cylinder structure on the output portion side".

[0018] In a high-power electron tube 100, it is necessary to improve the withstand voltage between the cathode lead 5 of the magnetron M1 to which a negative high voltage is applied as an input voltage and the anode cylindrical structure 1 having a ground potential. As shown in FIG. 1, the cathode lead 5 connected to the cathode 3 is fixed to the anode cylindrical structure 1 by an insulating member 8. The anode cylindrical structure 1 is sealed by the insulating member 8, and the cathode lead 5 is exposed from the vacuum vessel including the anode cylinder 2. In the magnetron M1 having such a structure, discharge or the like is likely to occur between the cathode lead 5 exposed from the insulating member 8 and the anode cylindrical structure 1. Therefore, in the electron tube 100 of the present embodiment, a shield case 9 is hermetically joined to the outer surface of the anode cylindrical structure 1 on the input portion side so as to surround a part of the cathode lead 5 exposed from the vacuum vessel. By configuring in this way, a part of the cathode lead 5 and a part of the anode cylindrical structure 1 where discharge or the like is likely to occur originally can be surrounded by the shield case 9. Further, the anode cylindrical structure 1 includes a communication hole 12 having a first opening 10 that opens in a region surrounded by the shield case 9 and a second opening 11 that opens in the waveguide W1.

[0019] The electron tube 100 of this embodiment, shown in Figure 1, is configured such that the input section from which the cathode lead 5 of the magnetron M1 is drawn out and the output section from which the antenna 6 is located and which emits microwaves to the outside are arranged perpendicular to the tube axis direction of the anode cylinder 2, with the anode cylinder 2 in between. Furthermore, the antenna 6, which is covered by the antenna cap 7, is inserted into the waveguide from the end face of the circular waveguide or the E-plane of the rectangular waveguide.Therefore, the communication hole 12, which has a first opening 10 that opens into the area surrounded by the shield case 9 on the outer surface of the anode cylinder structure 1 on the input section side and a second opening 11 that opens into the waveguide W1 on the outer surface of the anode cylinder structure 1 on the output section side, is configured such that the first hole portion 12a having the first opening 10 and the second hole portion 12b having the second opening 11 are directly connected. With this configuration, the communication holes 12 can be placed without increasing the area of ​​the anode cylindrical structure 1 surrounded by the shield case 9 or the area of ​​the anode cylindrical structure 1 surrounded by the waveguide W1. Furthermore, the communication holes 12 in this configuration can be easily formed by forming a linear first hole 12a from the outer surface of the anode cylindrical structure 1 on the input side, and then forming a linear second hole 12b from the outer surface of the anode cylindrical structure 1 on the output side.

[0020] The electron tube 100 of this embodiment, which can be used as a microwave oscillation source, is used, for example, by connecting a waveguide W1 that transmits microwaves to a Linac system. To improve the power handling capacity of the waveguide that transmits high-power microwaves, the waveguide, including the waveguide W1, is filled with pressurized dry air or highly insulating sulfur hexafluoride gas, or the inside of the waveguide is kept under vacuum. In this usage configuration, the electron tube 100 of this embodiment has communication holes 12 that connect the inside of the waveguide W1 to the inside of the shield case 9, and the shield case 9 is sealed to the outer surface of the anode cylindrical structure 1. As a result, the inside of the shield case 9 is also filled with pressurized dry air or highly insulating sulfur hexafluoride gas, or kept under vacuum.

[0021] As an example, the waveguide W1 and the shield case 9 are filled with dry air at a pressure of 2.5 kg / cm². 2 In this case, it became possible to form an electron tube with an input voltage of 46V and an output power of 3MW.

[0022] (Embodiment 2) Next, Embodiment 2 of the electron tube of the present invention will be described. Figure 2 is a schematic cross-sectional view illustrating Embodiment 2 of the electron tube of the present invention, and is a schematic cross-sectional view of the anode cylinder 2 along the tube axis direction. As shown in Figure 2, the electron tube 200 of this embodiment is configured such that a waveguide W2 is joined to the output section of a magnetron M2. Similar to the magnetron M1 described in Embodiment 1 above, the magnetron M2 has a cathode 3 and anode piece 4 arranged inside an anode cylinder 2 formed inside a rectangular anode cylinder structure 1. Below, the configuration of the input section, output section and communication hole 12 of the magnetron M2 will be described in detail.

[0023] In this embodiment, the electron tube 200 shown in Figure 2 has an input section from which the cathode lead 5 of the magnetron M2 is drawn out, which is positioned in the axial direction of the anode cylinder 2, and an output section from which the antenna 6 is located and which emits microwaves to the outside is positioned perpendicular to the axial direction of the anode cylinder 2. Furthermore, the antenna 6, which is covered by an antenna cap 7, is inserted into the waveguide from the end face of the circular waveguide or the E-plane of the rectangular waveguide.

[0024] A pair of ring-shaped magnets 13a and 13b and a yoke (not shown) are positioned on both sides of the anode cylindrical structure 1 at both ends of the anode cylinder 2 in the axial direction, forming a magnetic circuit. The magnetic forces of the magnets 13a and 13b in this magnetic circuit are applied to the working space between the cathode 3 and the tip of the anode piece 4 by pole pieces 14a and 14b, respectively.

[0025] The cathode 3 shown in Figure 2 is supported from the central axis direction by a cathode lead 5, and the cathode lead 5 is led out to the input section. The side of the anode cylindrical structure 1 from which the cathode lead 5 is led out becomes the "outer surface of the anode cylindrical structure on the input side." The side of the anode cylindrical structure 1 from which the antenna 6, covered by the antenna cap 7, protrudes and to which the waveguide W2 is joined becomes the "outer surface of the anode cylindrical structure on the output side."

[0026] As shown in Figure 2, the cathode lead 5 connected to the cathode 3 is fixed to the anode cylindrical structure 1 by an insulating member 8. The anode cylindrical structure 1 is sealed by the insulating member 8, and the cathode lead 5 is exposed from the vacuum vessel including the anode cylinder 2. In order to prevent discharge between the cathode lead 5 exposed from the insulating member 8 and the anode cylindrical structure 1, in the electron tube 200 of this embodiment, a shield case 9 is sealed and joined to the outer surface of the anode cylindrical structure 1 on the input side so as to surround a portion of the cathode lead 5 exposed from the vacuum vessel. With this configuration, a portion of the cathode lead 5 and a portion of the anode cylindrical structure 1, which are inherently prone to discharge, can be surrounded by the shield case 9. Furthermore, the anode cylindrical structure 1 is provided with a communication hole 12 having a first opening 10 that opens into the area surrounded by the shield case 9 and a second opening 11 that opens into the waveguide W2.

[0027] In this embodiment, the electron tube 200 shown in Figure 2 has an input section from which the cathode lead 5 of the magnetron M2 is drawn out, which is arranged along the tube axis direction of the anode cylinder 2. The output section, from which the antenna 6 is located and which emits microwaves to the outside, is arranged perpendicular to the tube axis direction of the anode cylinder 2, and the antenna 6, which is covered by an antenna cap 7, is inserted into the waveguide from the end face of the circular waveguide or the E-plane of the rectangular waveguide. In this configuration, the communication hole 12, which has a first opening 10 that opens into the area surrounded by the shield case 9 on the outer surface of the anode cylinder structure 1 on the input section side, and a second opening 11 that opens into the waveguide W2 on the outer surface of the anode cylinder structure 1 on the output section side, is configured such that the first hole portion 12a having the first opening 10 and the second hole portion 12b having the second opening 11 are directly connected. A communication hole 12 with this configuration can be easily formed by forming a linear first hole 12a from the outer surface of the anode cylindrical structure 1 on the input side, and further forming a linear second hole 12b from the outer surface of the anode cylindrical structure 1 on the output side. In this embodiment, it is possible to provide the communication hole 12 using only a relatively small area of ​​the anode cylindrical structure 1. Therefore, other structures provided in the anode cylindrical structure 1, such as cooling water passages, do not pose a problem when providing the communication hole 12.

[0028] In the electron tube 200 of this embodiment, which can be used as a microwave oscillation source, in order to improve the power withstand capability of the waveguide that transmits high-power microwaves, for example, pressurized dry air or highly insulating sulfur hexafluoride gas is filled inside the waveguide including the waveguide W2, or the inside of the waveguide is kept under vacuum. In this usage configuration, the electron tube 200 of this embodiment has communication holes 12 that connect the inside of the waveguide W2 to the inside of the shield case 9, and the shield case 9 is sealed to the outer surface of the anode cylindrical structure 1. As a result, the inside of the shield case 9 is also filled with pressurized dry air or highly insulating sulfur hexafluoride gas, or kept under vacuum.

[0029] (Embodiment 3) Next, Embodiment 3 of the electron tube of the present invention will be described. Figure 3 is a schematic cross-sectional view illustrating Embodiment 3 of the electron tube of the present invention, and is a schematic cross-sectional view of the anode cylinder 2 along the tube axis direction. As shown in Figure 3, the electron tube 300 of this embodiment is configured such that a waveguide W3 is joined to the output section of the magnetron M3. Similar to the magnetron M1 described in Embodiment 1 above, the magnetron M3 has a cathode 3 and an anode piece 4 arranged inside an anode cylinder 2 formed inside a rectangular anode cylinder structure 1. Below, the configuration of the input section, output section, and communication hole 12 of the magnetron M3 will be described in detail.

[0030] In this embodiment, the electron tube 300 shown in Figure 3 has an input section from which the cathode lead 5 of the magnetron M3 is drawn out, positioned perpendicular to the tube axis direction of the anode cylinder 2, and an output section from which the antenna 6 is positioned and microwaves are emitted to the outside, positioned in the tube axis direction of the anode cylinder 2. Furthermore, the antenna 6, which is covered by an antenna cap 7, is inserted into the waveguide from the E-plane of the rectangular waveguide.

[0031] A pair of ring-shaped magnets 13a and 13b and a yoke (not shown) are positioned on both sides of the anode cylindrical structure 1 at both ends of the anode cylinder 2 in the axial direction, forming a magnetic circuit. The magnetic forces of the magnets 13a and 13b in this magnetic circuit are applied to the working space between the cathode 3 and the tip of the anode piece 4 by pole pieces 14a and 14b, respectively.

[0032] The cathode 3 shown in Figure 3 is supported at both ends by cathode leads 5 from a direction perpendicular to the central axis of the cathode 3, similar to the support structure of the cathode 3 described in Embodiment 1 above, and the two cathode leads 5 are drawn out to the input section. The side of the anode cylindrical structure 1 from which the cathode leads 5 are drawn out becomes the "outer surface of the anode cylindrical structure on the input section side". The side of the anode cylindrical structure 1 from which the antenna 6, covered by the antenna cap 7, protrudes and to which the waveguide W3 is joined becomes the "outer surface of the anode cylindrical structure on the output section side".

[0033] As shown in Figure 3, the cathode lead 5 connected to the cathode 3 is fixed to the anode cylindrical structure 1 by an insulating member 8. The anode cylindrical structure 1 is sealed by the insulating member 8, and the cathode lead 5 is exposed from the vacuum vessel containing the anode cylinder 2. In order to prevent discharge between the cathode lead 5 exposed from the insulating member 8 and the anode cylindrical structure 1, in the electron tube 300 of this embodiment, a shield case 9 is sealed and joined to the outer surface of the anode cylindrical structure 1 on the input side so as to surround a portion of the cathode lead 5 exposed from inside the vacuum vessel. With this configuration, a portion of the cathode lead 5 and a portion of the anode cylindrical structure 1, which are inherently prone to discharge, can be surrounded by the shield case 9. Furthermore, the anode cylindrical structure 1 is provided with a communication hole 12 having a first opening 10 that opens into the area surrounded by the shield case 9 and a second opening 11 that opens into the waveguide W3. The second opening 11 is configured to open into the waveguide W3 by being placed in a through hole 15 formed on the E surface of the waveguide W3.

[0034] In this embodiment, the electron tube 300 shown in Figure 3 is configured such that the input section, from which the cathode lead 5 of the magnetron M3 is drawn out, is positioned perpendicular to the tube axis direction of the anode cylinder 2. The output section, from which the antenna 6 is positioned and which emits microwaves to the outside, is positioned along the tube axis direction of the anode cylinder 2, and the antenna 6, covered by the antenna cap 7, is inserted into the waveguide from the E-plane of the rectangular waveguide. Thus, the communication hole 12, which has a first opening 10 that opens into the region surrounded by the shield case 9 on the outer surface of the anode cylinder structure 1 on the input section side, and a second opening 11 that opens into the waveguide W3 through a through hole 15 formed in the waveguide W3 on the outer surface of the anode cylinder structure 1 on the output section side, is configured such that the first hole portion 12a having the first opening 10 and the second hole portion 12b having the second opening 11 are directly connected. A communication hole 12 with this configuration can be easily formed by forming a linear first hole 12a from the outer surface of the anode cylindrical structure 1 on the input side, and then forming a linear second hole 12b from the outer surface of the anode cylindrical structure 1 on the output side. In this embodiment, it is necessary to form a through hole in the waveguide W3 for inserting the output section of the magnetron M3 and a through hole 15 for opening the second opening 11, but these through holes can be easily formed in the normal waveguide manufacturing process. Furthermore, it is possible to provide the communication hole 12 using only a relatively small area of ​​the anode cylindrical structure 1. Therefore, other structures provided in the anode cylindrical structure 1, such as cooling water passages, do not pose a problem when providing the communication hole 12.

[0035] In the electron tube 300 of this embodiment, which can be used as a microwave oscillation source, in order to improve the power withstand capability of the waveguide that transmits high-power microwaves, for example, pressurized dry air or highly insulating sulfur hexafluoride gas is filled inside the waveguide including the waveguide W3, or the inside of the waveguide is kept in a vacuum state. In this usage configuration, in the electron tube 300 of this embodiment, the inside of the waveguide W3 and the inside of the shield case 9 are in communication through the communication hole 12, and the shield case 9 is sealed to the outer surface of the anode cylindrical structure 1, so the inside of the shield case 9 is also filled with pressurized dry air or highly insulating sulfur hexafluoride gas, or kept in a vacuum state. As a result, discharge between the cathode lead 5 exposed from the insulating member 8 and the anode cylindrical structure 1 is prevented, and it becomes possible to increase the voltage withstand capability of the input section.

[0036] (Embodiment 4) Next, Embodiment 4 of the electron tube of the present invention will be described. Figure 4 is a schematic cross-sectional view illustrating Embodiment 4 of the electron tube of the present invention, and is a cross-sectional view of the anode cylinder 2 along the tube axis direction. As shown in Figure 4, the electron tube 400 of this embodiment is configured such that a waveguide W4 is joined to the output section of a magnetron M4. Similar to the magnetron M1 described in Embodiment 1 above, the magnetron M4 has a cathode 3 and an anode piece 4 arranged inside an anode cylinder 2 formed inside a rectangular anode cylinder structure 1. Below, the configuration of the input section, output section, and communication hole 12 of the magnetron M4 will be described in detail.

[0037] The electron tube 400 of this embodiment, shown in Figure 4, has an input section from which the cathode lead 5 of the magnetron M4 is drawn out, and an output section where the antenna 6 is located and microwaves are emitted to the outside, both arranged in the direction of the tube axis of the anode cylinder 2, with the anode cylinder 2 in between. Furthermore, the antenna 6, which is covered by an antenna cap 7, is inserted into the waveguide from the E-plane of the rectangular waveguide.

[0038] A pair of ring-shaped magnets 13a and 13b and a yoke (not shown) are positioned on both sides of the anode cylindrical structure 1 at both ends of the anode cylinder 2 in the axial direction, forming a magnetic circuit. The magnetic forces of the magnets 13a and 13b in this magnetic circuit are applied to the working space between the cathode 3 and the tip of the anode piece 4 by pole pieces 14a and 14b, respectively.

[0039] The cathode 3 shown in Figure 4 is supported from the central axis direction by a cathode lead 5, similar to the support structure of the cathode 3 described in Embodiment 2 above, and the cathode lead 5 is led out to the input section. The side of the anode cylindrical structure 1 from which the cathode lead 5 is led out becomes the "outer surface of the anode cylindrical structure on the input section side". The side of the anode cylindrical structure 1 from which the antenna 6, covered by the antenna cap 7, protrudes and to which the waveguide W4 is joined becomes the "outer surface of the anode cylindrical structure on the output section side".

[0040] As shown in Figure 4, the cathode lead 5 connected to the cathode 3 is fixed to the anode cylindrical structure 1 by an insulating member 8. The anode cylindrical structure 1 is sealed by the insulating member 8, and the cathode lead 5 is exposed from the vacuum vessel containing the anode cylinder 2. In order to prevent discharge between the cathode lead 5 exposed from the insulating member 8 and the anode cylindrical structure 1, in the electron tube 400 of this embodiment, a shield case 9 is sealed and joined to the outer surface of the anode cylindrical structure 1 on the input side so as to surround a portion of the cathode lead 5 exposed from inside the vacuum vessel. With this configuration, a portion of the cathode lead 5 and a portion of the anode cylindrical structure 1, which are inherently prone to discharge, can be surrounded by the shield case 9. Furthermore, the anode cylindrical structure 1 is provided with a communication hole 12 having a first opening 10 that opens into the area surrounded by the shield case 9 and a second opening 11 that opens into the waveguide W4. The second opening 11 is configured to open into the waveguide W4 by being placed in a through hole 15 formed on the E surface of the waveguide W4.

[0041] The electron tube 400 of this embodiment, shown in Figure 4, is configured such that the input section, from which the cathode lead 5 of the magnetron M4 is drawn out, and the output section, from which the antenna 6 is located and which emits microwaves to the outside, are arranged in the direction of the tube axis of the anode cylinder 2, with the anode cylinder 2 in between. Furthermore, the antenna 6, which is covered by an antenna cap 7, is inserted into the waveguide from the E-plane of the rectangular waveguide.Therefore, the configuration includes a communication hole 12 having a first opening 10 that opens into the area surrounded by the shield case 9 on the outer surface of the anode cylinder structure 1 on the input section side, and a second opening 11 that opens into the waveguide W4 through a through hole 15 formed in the waveguide W4 on the outer surface of the anode cylinder structure 1 on the output section side.The communication hole 12 with this configuration can be easily formed by creating a linear through hole in a single process from the outer surface of the anode cylinder structure 1 on the input section side or the output section side, resulting in good workability.In addition, the position of the through hole can be easily selected. In this embodiment, it is necessary to form a through-hole in the waveguide W4 for inserting the output section of the magnetron M4 and a through-hole 15 for opening the second opening 11. These through-holes can be easily formed using the normal waveguide manufacturing process. Furthermore, it is possible to provide the communication hole 12 using only a very small area of ​​the anode cylindrical structure 1. Therefore, other structures such as cooling water passages do not pose a problem.

[0042] In the electron tube 400 of this embodiment, which can be used as a microwave oscillation source, in order to improve the power withstand capability of the waveguide that transmits high-power microwaves, pressurized dry air or highly insulating sulfur hexafluoride gas is filled inside the waveguide, including the waveguide W4, or the inside of the waveguide is kept under vacuum. In this usage configuration, the electron tube 400 of this embodiment has communication holes 12 that connect the inside of the waveguide W4 to the inside of the shield case 9, and the shield case 9 is sealed to the outer surface of the anode cylindrical structure 1. As a result, the inside of the shield case 9 is also filled with pressurized dry air or highly insulating sulfur hexafluoride gas, or kept under vacuum.

[0043] (Embodiment 5) Next, Embodiment 5 of the electron tube of the present invention will be described. Figure 5 is a schematic cross-sectional view illustrating Embodiment 5 of the electron tube of the present invention, and is a cross-sectional view perpendicular to the tube axis direction of the anode cylinder 2. As shown in Figure 5, the electron tube 500 of this embodiment is configured such that a waveguide W5 is joined to the output section of a magnetron M5. Similar to the magnetron M1 described in Embodiment 1 above, the magnetron M5 has a cathode 3 and anode piece 4 arranged inside an anode cylinder 2 formed inside a rectangular anode cylinder structure 1. In addition, a shield case 9 is sealed and joined to the outer surface of the anode cylinder structure 1 on the input side so as to surround a part of the cathode lead 5 that is exposed from inside the vacuum vessel. Furthermore, in this embodiment, a cooling water passage 16 for passing cooling water through the anode cylinder structure 1 is arranged along the tube axis direction of the anode cylinder 2. Below, the configuration of the input section, output section and communication hole 12 of the magnetron M5 will be described in detail.

[0044] In this embodiment, the electron tube 500 shown in Figure 5 has an input section from which the cathode lead 5 of the magnetron M5 is drawn out, and an output section where the antenna 6 is located and microwaves are emitted to the outside, both arranged perpendicular to the tube axis direction of the anode cylinder 2, with the anode cylinder 2 in between. Furthermore, the antenna 6, which is covered by an antenna cap 7, is inserted into the waveguide from the end face of the circular waveguide or the E-plane of the rectangular waveguide. In this embodiment, since a cooling water passage 16 is located in the anode cylinder structure 1, it is not possible to form a communication hole 12 in which the first hole 12a and the second hole 12b described in Figure 1 are directly connected.

[0045] Therefore, the communication hole 12, which has a first opening 10 that opens into the region surrounded by the shield case 9 on the outer surface of the anode cylindrical structure 1 on the input side, and a second opening 11 that opens into the waveguide W5 on the outer surface of the anode cylindrical structure 1 on the output side, is configured such that the first hole portion 12a having the first opening 10 and the second hole portion 12b having the second opening 11 are connected via the third hole portion 12c. Figure 6 is a partially enlarged view of the joint portion between the third hole portion 12c and the second hole portion 12b that constitute the communication hole 12 formed in the anode cylindrical structure 1. As shown in Figures 5 and 6, a recess 17 is formed on the outer surface of the anode cylindrical structure 1 in a direction perpendicular to the tube axis direction of the anode cylinder 2, and the third hole portion 12c is formed by covering the opening of this recess 17 with a lid portion 18. An internal recess opening 19 is opened inside the recess 17. The hole portion having this internal recess opening 19 and the second opening 11 becomes the second hole portion 12b. Although not shown in Figure 6, another recessed opening 19 is formed within the recess 17, and the hole having this recessed opening 19 and the first opening 10 becomes the first hole 12a. The communication hole 12, composed of the first to third holes 12a to 12c, can be easily formed by forming a recess 17 on the outer surface of the anode cylindrical structure 1, forming a linear first hole 12a so that it reaches the recess 17 from the outer surface of the anode cylindrical structure 1 on the input side and forms the recessed opening 19, and further forming a linear second hole 12b so that it reaches the recess 17 from the outer surface of the anode cylindrical structure 1 on the output side and forms the recessed opening 19, and covering the opening of the recess 17 with a cover portion 18. The cover portion 18 may be formed before or after the formation of the first hole portion 12a, etc.

[0046] In the electron tube 500 of this embodiment, which can be used as a microwave oscillation source, in order to improve the power withstand capability of the waveguide that transmits high-power microwaves, for example, pressurized dry air or highly insulating sulfur hexafluoride gas is filled inside the waveguide including the waveguide W5, or the inside of the waveguide is kept under vacuum. In this usage configuration, in the electron tube 500 of this embodiment, the inside of the waveguide W5 and the inside of the shield case 9 are connected by a communication hole 12, and the shield case 9 is sealed within the anode cylindrical structure 1. Therefore, the inside of the shield case 9 is also filled with pressurized dry air or highly insulating sulfur hexafluoride gas, or kept under vacuum. As a result, discharge between the cathode lead 5 exposed from the insulating member 8 and the anode cylindrical structure 1 is prevented, making it possible to increase the voltage withstand capability of the input section. In this embodiment, the third hole 12c is covered by the lid 18. The joint between the lid 18 and the anode cylindrical structure 1 is configured to have sufficient sealing strength to be maintained under the pressure of the air or gas filling the shield case 9 and the waveguide including the waveguide W5, or under a vacuum.

[0047] (Embodiment 6) Next, Embodiment 6 of the electron tube of the present invention will be described. Figure 7 is a schematic cross-sectional view illustrating Embodiment 6 of the electron tube of the present invention, and is a cross-sectional view perpendicular to the tube axis direction of the anode cylinder. As shown in Figure 6, the electron tube 600 of this embodiment is configured such that a waveguide W6 is joined to the output section of a magnetron M6. The magnetron M6 shown in Figure 7, like the magnetron M1 described in Embodiment 1 above, has a cathode 3 and anode piece 4 arranged inside an anode cylinder 2 formed inside a rectangular anode cylinder structure 1. Furthermore, a shield case 9 is sealed and joined to the outer surface of the anode cylinder structure 1 on the input side so as to surround a part of the cathode lead 5 that is exposed from inside the vacuum vessel. Furthermore, like Embodiment 5 above, a cooling water passage 16 for passing cooling water through the anode cylinder structure 1 is arranged along the tube axis direction of the anode cylinder 2. Below, the configuration of the input section, output section and communication hole 12 of the magnetron M6 will be described in detail.

[0048] In this embodiment, the electron tube 600 shown in Figure 7 has an input section from which the cathode lead 5 of the magnetron M6 is drawn out, and an output section where the antenna 6 is located and microwaves are emitted to the outside, both arranged perpendicular to the tube axis direction of the anode cylinder 2, with the anode cylinder 2 in between. Furthermore, the antenna 6, which is covered by an antenna cap 7, is inserted into the waveguide from the end face of the circular waveguide or the E-plane of the rectangular waveguide. In this embodiment as well, since a cooling water passage 16 is located in the anode cylinder structure 1, it is not possible to form a communication hole 12 in which the first hole 12a and the second hole 12b are directly connected, as described in Figure 1.

[0049] Therefore, the communication hole 12, which has a first opening 10 that opens into the region surrounded by the shield case 9 on the outer surface of the anode cylindrical structure 1 on the input side, and a second opening 11 that opens into the waveguide W6 on the outer surface of the anode cylindrical structure 1 on the output side, is configured such that the first hole portion 12a having the first opening 10 and the second hole portion 12b having the second opening 11 are connected via the fourth hole portion 12d. Figure 8 is a partially enlarged view of the joint portion between the fourth hole portion 12d and the second hole portion 12b that constitute the communication hole 12 formed in the anode cylindrical structure 1. As shown in Figures 7 and 8, a through hole 20 extending in a direction perpendicular to the tube axis direction of the anode cylinder 2 is formed near the surface of the anode cylindrical structure 1, and the fourth hole portion 12d is formed by closing both ends of this through hole 20 with a cover portion 21. An internal through hole opening 22 is opened in the through hole 20. The hole having the through-hole opening 22 and the second opening 11 becomes the second hole portion 12b. Although not shown in Figure 8, another through-hole opening 22 is formed within the through-hole opening 22 of the through-hole 20, and the hole having this through-hole opening 22 and the first opening 10 becomes the first hole portion 12a. The communication hole 12, composed of the first hole portion 12a, the second hole portion 12b, and the fourth hole portion 12d, can be easily formed by forming a through-hole 20 near the surface of the anode cylindrical structure 1, forming a linear first hole portion 12a that reaches the through-hole 20 from the outer surface of the anode cylindrical structure 1 on the input side and forms the through-hole opening 22, and further forming a linear second hole portion 12b that reaches the through-hole 20 from the outer surface of the anode cylindrical structure 1 on the output side and forms the through-hole opening 22, and closing the openings at both ends of the through-hole 20 with the cover portion 21. The lid portion 21 may be formed before or after the formation of the first hole portion 12a, etc.

[0050] In the electron tube 600 of this embodiment, which can be used as a microwave oscillation source, in order to improve the power withstand capability of the waveguide that transmits high-power microwaves, the waveguide, including the waveguide W6, is filled with pressurized dry air or sulfur hexafluoride gas with high insulating properties, or the inside of the waveguide is kept under vacuum. In this usage configuration, the electron tube 600 of this embodiment has communication holes 12 that connect the inside of the waveguide W6 to the inside of the shield case 9, and the shield case 9 is sealed within the anode cylindrical structure 1. As a result, the inside of the shield case 9 is also filled with pressurized dry air or sulfur hexafluoride gas with high insulating properties, or is kept under vacuum. In this embodiment, the fourth hole 12d is closed by the lid 21. The joint between the lid 21 and the anode cylindrical structure 1 is configured to have sufficient sealing strength to be maintained under the pressure of the air or gas filling the shield case 9 and the waveguide including the waveguide W6, or under a vacuum.

[0051] As explained above, since the electron tubes 100 to 600 of this embodiment do not use any materials that deteriorate at high temperatures, there is no problem even if the anode cylindrical structure 1 or the shield case 9 becomes hot. Furthermore, even if the gas inside the shield case 9 expands due to heat, the inside of the shield case 9 is in communication with the waveguide W2, which has a relatively large volume, through the communication hole 12, so the pressure inside the shield case 9 does not increase, and the joint strength between the shield case 9 and the anode cylindrical structure 1, or the joint strength between the lid 21 and the anode cylindrical structure 1, does not deteriorate.

[0052] Therefore, in this embodiment, the electron tubes 100 to 600 prevent discharge within the shield case 9 without requiring a complex structure, allowing for the application of a high input voltage and enabling higher output power of the electron tubes. Furthermore, they can be used in high-altitude areas where discharge is likely to occur.

[0053] Although embodiments of the electron tube of the present invention have been described above, it goes without saying that the present invention is not limited to the above embodiments. For example, the connection structure between the magnetron and the waveguide, the arrangement of the input and output sections of the magnetron, etc., can be changed as appropriate. The communication hole 12 can be changed as appropriate as long as it has a configuration having at least a first opening 10 that opens into the area surrounded by the shield case 9 and a second opening 11 that opens into the waveguide. The anode cylindrical structure 1 can be configured to include, for example, a part of a member that does not constitute an anode, such as a spacer. Furthermore, the anode cylindrical structure 1 is not limited to a rectangle as long as it can be sealed and joined to the shield case 9 and the waveguide.

[0054] (summary) (1) One embodiment of the electron tube of the present invention comprises a cathode that emits thermionic electrons, an anode in which a plurality of anode pieces are arranged in an anode cylinder inside an anode cylindrical structure so as to surround the cathode and a cavity resonator is formed between the anode pieces, an input section from which a cathode lead is drawn out for applying an input voltage to the cathode, an output section that emits microwaves excited by the cavity resonator to the outside, and a waveguide that transmits microwaves emitted from the output section, wherein a sealable shield case surrounding a part of the cathode lead is joined to the outer surface of the anode cylindrical structure on the input section side, and a sealable waveguide is joined to the outer surface of the anode cylindrical structure on the output section side, and the anode cylindrical structure is configured to have a communication hole having a first opening that opens into the region surrounded by the shield case and a second opening that opens into the waveguide.

[0055] In the electron tube of the embodiment described in (1) above, a communication hole is provided with an opening in the region surrounded by a shielding case that covers a part of the cathode lead to which an input voltage is applied to the cathode, and in the waveguide that transmits microwaves emitted from the output section. As a result, the inside of the waveguide that transmits high-power microwaves and the inside of the shielding case are in communication, improving the voltage withstand capability of the input section and making it possible to provide a high-power electron tube.

[0056] (2) According to another embodiment, in the electron tube of (1) above, the second opening is located in a through hole formed in the wall surface of the waveguide.

[0057] (3) In yet another embodiment, in the electron tube of (1) or (2) above, the communication hole is configured such that a first hole portion having the first opening and a second hole portion having the second opening are directly connected.

[0058] (4) According to yet another embodiment, in the electron tube of (1) or (2) above, the anode cylindrical structure has a third hole portion comprising a recess formed in the anode cylindrical structure and a lid portion covering the opening of the recess, and the communication hole is configured such that a first hole portion having the first opening and a second hole portion having the second opening are connected via the third hole portion.

[0059] (5) According to yet another embodiment, in the electron tube of (1) or (2) above, the anode cylindrical structure has a fourth hole portion comprising a through hole penetrating the anode cylindrical structure and a lid portion covering the opening of the through hole, and the communication hole is configured such that a first hole portion having the first opening and a second hole portion having the second opening are connected via the fourth hole portion.

[0060] (6) According to yet another embodiment, in the electron tube of (1) or (2) above, the waveguide and the shield case communicating through the communication hole are sealed, and the inside of the waveguide and the inside of the shield case are configured to be at equal pressure and / or atmosphere. [Explanation of symbols]

[0061] 100~600 electron tube M1~M6 Magnetron W1~W6 Waveguide 1. Anode cylindrical structure 2 Anode cylinders 3 Cathode 4 anodes 5 Cathode Leads 6 Antennas 7 Antenna cap 8. Insulating material 9 Shield Case 10. First opening 11. Second opening 12 Communication hole 12a~12d 1st~4th hole 13a, 13b Magnets 14a, 14b pole pieces 15, 20 through holes 16 Cooling water passage 17 recess 18, 21 Lid 19 Recessed inner opening 22 Through hole opening

Claims

1. A cathode that emits thermionic electrons, An anode in which a plurality of anode pieces are arranged around the cathode in an anode cylinder inside an anode cylindrical structure, and a cavity resonator is formed between the anode pieces, An input section from which a cathode lead is drawn out to apply an input voltage to the cathode, An output unit that emits microwaves excited by the aforementioned cavity resonator to the outside, A waveguide for transmitting microwaves emitted from the output unit and An electron tube comprising, A sealable shield case surrounding a portion of the cathode lead is joined to the outer surface of the anode cylindrical structure on the input side. A sealable waveguide is joined to the outer surface of the anode cylindrical structure on the output side. The anode cylindrical structure is provided with a communication hole having a first opening that opens into the region surrounded by the shield case and a second opening that opens into the waveguide. electron tube.

2. The second opening is located within a through-hole formed in the wall surface of the waveguide. The electron tube according to claim 1.

3. The communication hole is formed by directly connecting a first hole portion having the first opening and a second hole portion having the second opening. The electron tube according to claim 1 or 2.

4. The anode cylindrical structure has a third hole portion which is composed of a recess formed in the anode cylindrical structure and a lid portion which covers the opening of the recess. The communication hole is configured such that the first hole having the first opening and the second hole having the second opening are connected via the third hole. The electron tube according to claim 1 or 2.

5. The anode cylindrical structure has a fourth hole portion which is composed of a through hole that penetrates the anode cylindrical structure and a lid portion that covers the opening of the through hole. The communication hole is configured such that the first hole having the first opening and the second hole having the second opening are connected via the fourth hole. The electron tube according to claim 1 or 2.

6. The waveguide and the shield case communicating through the communication hole are sealed, and the inside of the waveguide and the inside of the shield case are under equal pressure and / or atmosphere. The electron tube according to claim 1 or 2.

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