CN116997987A

CN116997987A - Klystron device

Info

Publication number: CN116997987A
Application number: CN202280021566.5A
Authority: CN
Inventors: 藤井令史; 大久保良久
Original assignee: Toshiba Electron Tubes and Devices Co Ltd
Current assignee: Canon Electron Tubes and Devices Co Ltd
Priority date: 2021-03-17
Filing date: 2022-03-14
Publication date: 2023-11-03

Abstract

Provided is a klystron device capable of improving output conversion efficiency. The klystron device comprises a klystron body and a focusing magnetic field device. The klystron body has an electron gun section, a collector section, a plurality of cavity resonators, and a plurality of drift tubes. The cavity resonator has end portions that are axially opposed to each other to form a gap portion that communicates with the drift tube. At least one of the cavity resonators has an electric field correction section at a part of the end section, the electric field correction section making a spacing of the gap section different from a spacing at the end section.

Description

Klystron device

Technical Field

Embodiments of the present invention relate to a klystron device that amplifies high frequencies.

Background

The klystron device, i.e. the multibeam klystron, comprises: an electron gun section that generates an electron beam; a collector portion that captures an electron beam; a plurality of cavity resonators disposed between the electron gun section and the collector section; a plurality of klystron bodies having a plurality of drift tubes in axial communication with a plurality of cavity resonators; and a focusing magnetic field device that focuses the electron beam. The plurality of cavity resonators constitute an input cavity into which high frequencies are input, a plurality of intermediate cavities, and an output cavity into which amplified high frequencies are output.

In addition, the electron beam enters the input cavity from the electron gun part, the high frequency phase inputted to the input cavity accelerates and decelerates the electrons to perform velocity modulation, density modulation in which the electrons are respectively concentrated by the accelerated electrons and the decelerated electrons occurs during traveling in a uniform electric field, so that the electrons are clustered, the clustered electrons become gradually stronger due to the self-induced high frequency electric field in the intermediate cavity, and the clustered electrons induce a strong alternating current electric field when passing through the output cavity, thereby outputting amplified high power high frequency from the output cavity to the outside.

In the klystron device described above, when there is an electron beam in a region where the change in the electric field intensity distribution is small, electrons are accelerated and decelerated in a substantially uniform electric field, but when the electron beam reaches a region where the change in the electric field intensity distribution is large, the electric field for accelerating and decelerating electrons is no longer axisymmetric with respect to the axis of the electron beam, and therefore, the electron bunching becomes non-axisymmetric, resulting in fluctuation of the trajectory of the electron beam and a reduction in the operation efficiency, and thus in a reduction in the output conversion efficiency.

Alternatively, in the above-described klystron device, when the cavity voltages in the radial direction and the circumferential direction at the cavity resonator are substantially uniform, electrons are accelerated and decelerated by the substantially uniform cavity resonator voltages, but when the cavity voltages in the radial direction and the circumferential direction at the cavity resonator are non-uniform, the cavity resonator voltages for accelerating and decelerating electrons are no longer axisymmetric with respect to the axis of the electron beam, and therefore, energy dispersion in the cluster of the electron beam increases, resulting in a fluctuation in the trajectory of the electron beam and a reduction in the operation efficiency, and a reduction in the output conversion efficiency.

Prior art literature

Patent literature

Patent document 1: japanese patent No. 4653649

Disclosure of Invention

Technical problem to be solved by the invention

The present embodiment provides a klystron device capable of improving output conversion efficiency.

Technical proposal adopted for solving the technical problems

The klystron device of an embodiment comprises a klystron body and a focusing magnetic field device for focusing an electron beam. The klystron body has: an electron gun section that generates an electron beam; a collector portion that captures an electron beam; a plurality of cavity resonators disposed between the electron gun section and the collector section; and a plurality of drift tubes that communicate with the plurality of cavity resonators in the axial direction. The cavity resonator has end portions that are axially opposed to each other to form a gap portion that communicates with the drift tube. At least one cavity resonator has an electric field correction portion at a portion of the end portion, the electric field correction portion making a spacing of the gap portion different from a spacing at the end portion.

In addition, the klystron device of an embodiment comprises a klystron body and a focusing magnetic field device that focuses the electron beam. The klystron body has: an electron gun section that generates an electron beam; a collector portion that captures an electron beam; a plurality of cavity resonators disposed between the electron gun section and the collector section; and a plurality of drift tubes that communicate with the plurality of cavity resonators in the axial direction. The cavity resonator has end portions that are axially opposed to each other to form a gap portion that communicates with the drift tube. At least one cavity resonator has a cavity resonator voltage correction section provided at a position corresponding to an end in a circumferential direction of the cavity resonator so that an interval of the gap section becomes large.

Drawings

Fig. 1 is a sectional view showing a klystron device of a first embodiment.

Fig. 2A is a cross-sectional view showing a cavity resonator of the upper klystron device and in a direction intersecting the axial direction.

Fig. 2B is an enlarged sectional view showing a cavity resonator of the same as the upper klystron device and in an axial direction.

Fig. 3 is a perspective view of a portion of the same upper cavity resonator.

Fig. 4 is a graph showing a relationship between a normalized radius centered on the axis of the drift tube of the upper cavity resonator and an electric field intensity in the normalized axis direction.

Fig. 5 is an electric field intensity distribution diagram of the periphery of the drift tube of the upper cavity resonator.

Fig. 6 is a perspective view showing a part of a cavity resonator of a klystron device of the second embodiment.

Fig. 7 is a graph showing a relationship between a normalized radius centered on the axis of the drift tube of the upper cavity resonator and an electric field intensity in the normalized axis direction.

Fig. 8 is an electric field intensity distribution diagram of the periphery of the drift tube of the upper cavity resonator.

Fig. 9 is a perspective view showing a part of a cavity resonator of the third embodiment.

Fig. 10 is a graph showing a relationship between a normalized radius centered on the axis of the drift tube of the upper cavity resonator and an electric field intensity in the normalized axis direction.

Fig. 11 is an electric field intensity distribution diagram of the periphery of the drift tube of the upper cavity resonator.

Fig. 12 is a perspective view showing a part of a cavity resonator of the fourth embodiment.

Fig. 13 is a graph showing a relationship between a normalized radius centered on the axis of the drift tube of the upper cavity resonator and an electric field intensity in the normalized axis direction.

Fig. 14 is an electric field intensity distribution diagram of the periphery of the drift tube of the upper cavity resonator.

Fig. 15 is a perspective view of a part of the cavity resonator of the first comparative example.

Fig. 16 is a graph showing a relationship between a normalized radius centered on the axis of the drift tube of the cavity resonator of the first comparative example and an electric field strength in the normalized axis direction.

Fig. 17 is an electric field intensity distribution diagram of the periphery of the drift tube of the cavity resonator of the comparative example.

Fig. 18 is a sectional view showing a klystron device of the fifth embodiment.

Fig. 19A is a cross-sectional view showing a cavity resonator of the klystron device of the fifth embodiment and in a direction intersecting the axial direction.

Fig. 19B is an enlarged sectional view in the axial direction showing a cavity resonator of the klystron device of the fifth embodiment.

Fig. 20 is a perspective view of a part of the cavity resonator of the fifth embodiment.

Fig. 21 is an electric field intensity distribution diagram around the drift tube of the cavity resonator according to the fifth embodiment.

Fig. 22 is a graph showing a relationship between a normalized radius centered on the axis of the drift tube of the cavity resonator according to the fifth embodiment and an electric field intensity in the normalized axis direction.

Fig. 23 is a graph showing the relationship between the on-axis position of each cavity voltage evaluation axis of the cavity resonator according to the fifth embodiment and the normalized axial electric field intensity.

Fig. 24 is a table of normalized cavity resonator voltages regarding the fifth embodiment and comparative example two considering the beam coupling coefficient of each cavity resonator voltage evaluation axis of the cavity resonator.

Fig. 25 is a perspective view showing a part of a cavity resonator of a klystron device of the sixth embodiment.

Fig. 26 is an electric field intensity distribution diagram around the drift tube of the cavity resonator according to the sixth embodiment.

Fig. 27 is a graph showing a relationship between a normalized radius centered on the axis of the drift tube of the cavity resonator according to the sixth embodiment and an electric field intensity in the normalized axis direction.

Fig. 28 is a graph showing the relationship between the on-axis position of each cavity voltage evaluation axis of the cavity resonator according to the sixth embodiment and the normalized axial electric field intensity.

Fig. 29 is a table of normalized cavity resonator voltages regarding the sixth embodiment and comparative example three in consideration of the beam coupling coefficient of each cavity resonator voltage evaluation axis of the cavity resonator.

Fig. 30 is a perspective view of a part of the cavity resonator of the second comparative example.

Fig. 31 is a graph showing a relationship between a normalized radius centered on the axis of the drift tube of the cavity resonator of the second comparative example and an electric field strength in the normalized axis direction.

Fig. 32 is a graph showing the relationship between the on-axis position of the voltage evaluation axis of each cavity resonator of the second comparative example and the electric field intensity in the normalized axis direction.

Fig. 33 is a perspective view of a part of the cavity resonator of the fourth comparative example.

Fig. 34 is a graph showing a relationship between a normalized radius centered on the axis of the drift tube of the cavity resonator of the fourth comparative example and the electric field intensity in the normalized axis direction.

Fig. 35 is a graph showing the relationship between the on-axis position of the voltage evaluation axis of each cavity resonator of the fourth comparative example and the electric field intensity in the normalized axis direction.

Fig. 36 is a table of normalized cavity resonator voltages regarding the second and fourth comparative examples in consideration of the beam coupling coefficient of each cavity resonator voltage evaluation axis of the cavity resonator.

Fig. 37 is a perspective view of a part of the cavity resonator of the fifth comparative example.

Fig. 38 is a perspective view of a part of the cavity resonator of the sixth comparative example.

Fig. 39 is a table of normalized cavity resonator voltages regarding comparative example five and comparative example six in consideration of the beam coupling coefficient of each cavity resonator voltage evaluation axis of the cavity resonator.

Detailed Description

A first embodiment will be described below with reference to fig. 1 to 5.

An example of a multiple beam klystron 10 as a klystron device is shown in fig. 1.

The multibeam klystron 10 includes a klystron body 11 and a focusing magnetic field device 13 disposed around a central axis 12, which is a tube axis of the klystron body 11.

The klystron main body 11 includes an electron gun section 20, an interaction section 21, a collector section 22, and an input circuit section 23 and an output circuit section 24 connected to the interaction section 21.

The electron gun portion 20 includes a plurality of cathodes 27 and a plurality of anodes 28 respectively opposing the cathodes 27. The plurality of cathodes 27 and the plurality of anodes 28 are arranged at equal intervals on the same circumference having a predetermined radius from the central axis 12 of the klystron body 11, and generate a plurality of electron beams in the axial direction.

The interaction portion 21 includes a plurality of cavity resonators 31 arranged in the axial direction between the electron gun portion 20 and the collector portion 22, and a plurality of drift tubes (drift holes) 32 that axially communicate the plurality of cavity resonators 31. The cavity resonator 31 is a coaxial cylinder TMmn0 mode (m.gtoreq.0, n.gtoreq.1), and in this embodiment, a coaxial cylinder TM010 mode is used. That is, the plurality of drift tubes 32 communicating with the cavity resonator 31 are arranged so as to face each other on the central axes of the plurality of cathodes 27 of the electron gun section 20 and so as to be aligned at equal intervals on the same circumference of a predetermined radius from the central axis 12 of the klystron main body 11, and pass through the electron beams from the cathodes 27.

The plurality of cavity resonators 31 are each configured with an input cavity 33 for inputting a high frequency from the input circuit unit 23, a plurality of intermediate cavities 34, and an output cavity 35 for outputting an amplified high frequency to the output circuit unit 24, in order from the electron gun unit 20 toward the collector unit 22.

As shown in fig. 1 to 3, the cavity resonator 31 has a cylindrical or annular cavity 36 centered on the central axis 12. End portions 37 (Japanese: a thickness portion 37) protrude from inner surfaces of the cavity 36 facing each other in the axial direction, and the end portions 37 communicate with the plurality of drift tubes 32. The end 37 is provided in a ring shape protruding in the circumferential direction of the cavity 36 at a radially central position of the cavity 36. A gap portion 38 is formed between axially opposite end portions 37 at a predetermined interval d communicating with the drift tube 32.

The axially opposite end portions 37 are provided with electric field correction portions 39 for correcting the electric field strength. The electric field correction portion 39 is formed of protrusions 40 that are located at both radial side positions with respect to the center of the drift tube 32 and protrude from both inner and outer diameter side positions of the end portion 37. The electric field correction portion 39 protrudes in a ring shape along the circumferential direction of the end portion 37 at a position where the surface of the end portion 37 is separated from the position of the drift tube 32. An inclined surface 41 is formed on a side surface of the protrusion 40 opposite to the drift tube 32 and facing the cavity 36. The gap portion 38 between the protrusions 40 of the axially opposed electric field correction portions 39 has a smaller interval d1 than the interval d between the end portions 37, and constitutes a radial electric field correction gap portion.

A magnetic body 43 for forming a plurality of magnetic field sections is disposed around the klystron body 11 between the anode 28 and the collector pole piece 42 on the collector portion 22 side.

Further, the focusing magnetic field means 13 generates a magnetic field for focusing the electron beam, for example, constituted by an electromagnet. The focusing magnetic field device 13 includes a magnetic frame 50 for forming a plurality of magnetic field sections together with the plurality of magnetic bodies 43 of the klystron main body 11, and a plurality of coils 51 arranged in each magnetic field section.

The focusing magnetic field device 13 generates a magnetic field parallel to the tube axis of the klystron body 11 at different magnetic field strengths in each magnetic field section. Two magnetic field intervals are provided from the anode 28 of the klystron body 11 to the input cavity 33. These two magnetic field intervals are matching sections for focusing the electron beam from the cathode 27 and making the electron beam parallel to the tube axis of the klystron body 11 after the electron beam is inputted into the cavity 33.

Furthermore, the electron beam, which becomes a desired diameter through the matching section, enters the input cavity 33. The high frequency phase input to the input cavity 33 accelerates and decelerates electrons to perform velocity modulation, and density modulation in which electrons are accelerated and decelerated during traveling in a uniform electric field are respectively collected so that electrons are clustered. The clustered electrons are gradually intensified by the self-induced high frequency electric field in the plurality of intermediate cavities 34. The clustered electrons induce a strong alternating electric field while passing through the output cavity 35, thereby outputting amplified high power high frequency from the output cavity 35 to the outside.

The input circuit unit 23 includes an input window 60 for inputting a high frequency from the outside, and an input waveguide 61 for guiding the high frequency input from the input window 60 to the input cavity 33.

The output circuit portion 24 includes an output window 62 for outputting the amplified high frequency to the outside, and an output waveguide 63 for guiding the high frequency output from the output cavity 35 to the output window 62.

In general, in a multibeam klystron, the ratio of beam current to beam voltage, which is called the coefficient of conductivity per single electron beam, can be controlled to be low by a plurality of cathodes and a plurality of drift tubes, and the total coefficient of conductivity can be set to a large value. It is known in the art that the smaller the coefficient of deflection per single electron beam, the higher the output conversion efficiency of the multibeam klystron. The multiple beam klystron design enables operation at low voltages and high efficiency compared to single beam klystron designs.

For example, in a multibeam klystron having a peak output exceeding megawatts, there is an L-band 10MW klystron having a coaxial cylinder in which cathodes are arranged at equal intervals on a circumference, a drift tube is provided on a central axis of each cathode, and a cavity resonator is arranged so as to have a diameter concentric with the circle on which the cathode of TM010 mode is arranged, and an electric field strength in an axial direction in a cavity is maximized on an axis of the drift tube (i.e., an axis of an electron beam).

The multibeam klystron design is characterized in that the electric field intensity distribution is axisymmetric with respect to the axis of each electron beam, and high-efficiency operation is realized by the interaction between the electron beam and the electric field having the electric field intensity distribution which is equal and axisymmetric with respect to the axis of each electron beam.

By applying this method for designing a multibeam klystron to a pulse klystron having a peak output of several megawatts or more, the pulse klystron can be operated efficiently at the same operating voltage, and thus, improvement of performance such as halving the operating voltage at the same operating efficiency can be expected.

The multi-beam klystron for lowering the operating voltage can achieve a design for improving the total inductance by setting the inductance of each single electron beam to a relatively high value and using a large number of electron beams. The interaction part of the multi-beam klystron design is shortened, so that the multi-beam klystron design has the advantage of miniaturization.

The multibeam klystron design increases the current per single electron beam compared to a low coefficient of flow multibeam klystron, and therefore, increases the focused magnetic field strength of the focused electron beam. To improve this, it is effective to increase the diameter of the electron beam so as to reduce the current density of the electron beam.

In the case of the cavity resonator being in the TM0n0 mode of the coaxial, the electric field strength varies in the radial direction but is constant in the axial direction. The axis of the electron beam is typically placed at a radial position where the electric field strength in the axial direction is maximum. If an electron beam exists in a region where there is little change in the electric field intensity in the axial direction, electrons are accelerated and decelerated in a substantially uniform electric field. However, when the electron beam exists in a region where the variation of the electric field intensity distribution is large, that is, when the diameter of the drift tube is large relative to the radial dimension of the cavity, the electric field for accelerating and decelerating the electrons is no longer axisymmetric relative to the axis of the electron beam, and the group fusion of the electrons becomes non-axisymmetric, resulting in a fluctuation of the orbit of the electron beam and a decrease in the operation efficiency. In the case of a C-band or X-band of a multibeam klystron in which the diameter of the drift tube of the cavity resonator is large relative to the wavelength at the resonance frequency, for example, the peak output power of several megawatts, this tendency becomes remarkable when the diameter of the drift tube exceeds about 0.2 times the cutoff diameter of the TE11 mode at the resonance frequency of the cavity as a criterion of the relation between the cavity and the diameter of the drift tube.

Therefore, in the present embodiment, even when the drift tube 32 has a large diameter with respect to the wavelength at the resonance frequency, the non-axisymmetry of the electric field intensity distribution in the circumferential direction and the radial direction at the cavity 36 of the cavity resonator 31 can be corrected so that the electric field intensity distribution is axisymmetric with respect to the axis of the electron beam. Accordingly, the energy dispersion in the cluster of electrons accelerated and decelerated by the electric field is reduced, and the reduction in the operation efficiency is suppressed, thereby providing the multibeam klystron 10 with improved conversion efficiency.

In order to operate the multibeam klystron 10 efficiently, it is effective to accelerate and decelerate electrons in a distribution in which the electric field of the cavity resonator 31 interacting with the electron beam is uniform with respect to the electron beam, that is, in a distribution in which the difference between the maximum electric field intensity and the average electric field intensity interacting with the electron beam is small.

In the case where the cavity resonator 31 is a TM010 mode of a coaxial cylinder, the electric field intensity distribution in the circumferential direction at the same radial position is the same value regardless of the circumferential phase, and therefore, the electric field intensity distribution at each of the drift tubes 3 arranged on the coaxial circumference is the same. On the other hand, since the electric field intensity distribution at the radial position has a mountain-shaped distribution having a peak of the electric field intensity, the change in the electric field intensity interacting with the electron beam increases according to the relationship between the resonance frequency in the cavity 36 and the diameter dimension of the drift tube 32, and an electric field intensity distribution different from the circumferential direction is formed.

To solve this problem, in the present embodiment, an electric field correction section 39 is included. The cavity shape and the electric field intensity distribution of the present embodiment including the electric field correction portion 39 are shown in fig. 3 to 5, and the cavity shape and the electric field intensity distribution of the first comparative example not including the electric field correction portion 39 are shown in fig. 15 to 17. Fig. 3 and 15 are perspective views of a part of the cavity resonator 31, fig. 4 and 16 are graphs showing the relationship between the normalized radius and the normalized axial electric field intensity about the axis of the drift tube 32 of the cavity resonator 31, and fig. 5 and 17 show electric field intensity distribution diagrams around the drift tube 32 of the cavity resonator 31. The broken line in fig. 7 shows the electric field intensity distribution of the first comparative example, and the solid line in fig. 7 shows the electric field intensity distribution of the present embodiment.

First, in the case of the first comparative example, as described above, the electric field intensity distribution is non-axisymmetric with respect to the axis of the electron beam in the circumferential direction and the radial direction, and the energy dispersion in the cluster of electrons accelerated and decelerated by the non-axisymmetric electric field increases, and the operation efficiency decreases, resulting in a decrease in the output conversion efficiency.

In the case of the present embodiment, the protrusion 40 of the electric field correction portion 39 narrows the interval of the gap portion 38, thereby increasing the electric field intensity in the radial direction and making the electric field intensity distribution axisymmetric in the circumferential direction and the radial direction with respect to the axis of the electron beam. In the normal design, the electric field intensity at about 70% of the diameter of the drift tube 32, which is the outermost diameter of the electron beam, is 15% different between the circumferential direction and the radial direction in the first comparative example, and this difference can be improved to about 3% in the present embodiment.

In this way, by correcting the non-axisymmetry of the electric field intensity distribution in the circumferential direction and the radial direction at the cavity 36 of the cavity resonator 31 to axisymmetric the electric field intensity distribution with respect to the axis of the electron beam, the energy dispersion in the cluster of electrons accelerated and decelerated by the electric field can be reduced, and the output conversion efficiency can be improved while suppressing the reduction in the operation efficiency.

Further, in the case where there is a tendency that the electric field intensity distribution is not axisymmetric with respect to the axis of the electron beam, that is, the diameter of the drift tube 32 is 0.2 times or more the cutoff diameter of the TE11 mode at the resonance frequency of the cavity resonator 31 and the diameter of the drift tube 32 is relatively large with respect to the wavelength at the resonance frequency, it is possible to correct the non-axisymmetry of the electric field intensity distribution in the circumferential direction and the radial direction at the cavity 36 of the cavity resonator 31 and axisymmetric the electric field intensity distribution with respect to the axis of the electron beam.

The electric field correction unit 39 is provided on the surface of the end 37 at a position separated from the position of the drift tube 32, so that the radial electric field intensity distribution in the cavity 36 of the cavity resonator 31 can be made close to the circumferential electric field intensity distribution.

Next, a second embodiment is shown in fig. 6 to 8.

As shown in fig. 6, the electric field correction portion 39 includes concave portions 70, the concave portions 70 being provided at both side positions in the circumferential direction with respect to the drift tube 32 on the surfaces of the end portions 37 axially opposite to each other. The recess 70 is formed in a circular concave shape, for example, so as to be recessed from the surface of the end 37 at a position separated from the position of the drift tube 32 on the surface of the end 37. The gap portions 38 between the axially opposite concave portions 70 have a spacing wider than the spacing d between the end portions 37 and constitute circumferential electric field correction gap portions.

Further, the gap 38 is widened by the concave portion 70 of the electric field correction portion 39, so that the electric field intensity in the circumferential direction with respect to the axis of the drift tube 32 is reduced, and the electric field intensity distribution can be made axisymmetric with respect to the axis of the electron beam by bringing the electric field intensities in the circumferential direction and the radial direction closer to each other.

The provision of only the concave portion 70 of the electric field correction portion 39 in the cavity resonator 31 has the effect of bringing the electric field intensity distribution in the circumferential direction and the radial direction close to each other, but by including both the radial direction protruding portion 40 and the circumferential direction concave portion 70 as the electric field correction portion 39, it is possible to easily achieve the balance between the electric field intensity distribution in the circumferential direction and the electric field intensity distribution in the radial direction, and to control the shape of the electric field intensity distribution to a certain extent while achieving the axisymmetry with respect to the axis of the electron beam.

Next, fig. 9 to 11 show a third embodiment.

As in the second embodiment, the electric field correction portion 39 includes the concave portions 70 provided at both side positions in the circumferential direction with respect to the drift tube 32 on the surfaces of the axially opposite end portions 37, but the range of the concave portions 70 is further enlarged. For example, two circular recesses 70 are provided in such a manner as to partially overlap each other.

Further, the range in which the gap portion 38 is widened is enlarged by the concave portion 70 of the electric field correction portion 39, so that the electric field intensity in the circumferential direction with respect to the axis of the drift tube 32 is further reduced, and the electric field intensity in the circumferential direction and the electric field intensity in the radial direction are brought close to each other, whereby the electric field intensity distribution can be axisymmetric with respect to the axis of the electron beam.

Next, fig. 12 to 14 show a fourth embodiment.

The end portion 37 is provided in a cylindrical shape protruding from the periphery of the drift tube 32 with respect to each drift tube 32.

The electric field correction portion 39 is constituted by protrusions 40 protruding from both side positions in the radial direction around the drift tube 32.

Further, the protrusion 40 of the electric field correction portion 39 makes the interval of the gap portion 38 narrower than the interval at the end portion 37, thereby increasing the electric field intensity in the radial direction with respect to the axis of the drift tube 32, and making the electric field intensity distribution axisymmetric with respect to the axis of the electron beam by making the electric field intensity in the circumferential direction and the radial direction close.

Embodiment 5 will be described below with reference to fig. 18 to 24.

An example of a multiple beam klystron 110 as a klystron device is shown in fig. 18.

The multibeam klystron 110 includes a klystron body 111 and a focusing magnetic field device 113 disposed around a central axis 112, which is a tube axis of the klystron body 111.

The klystron main body 111 includes an electron gun section 120, an interaction section 121, a collector section 122, and an input circuit section 123 and an output circuit section 124 connected to the interaction section 121.

The electron gun portion 120 includes a plurality of cathodes 127 and a plurality of anodes 128 respectively facing the cathodes 127. The plurality of cathodes 127 and the plurality of anodes 128 are arranged at equal intervals on the same circumference having a predetermined radius from the central axis 112 of the klystron body 111, and generate a plurality of electron beams in the axial direction.

The interaction unit 121 includes a plurality of cavity resonators 131 arranged in the axial direction between the electron gun unit 120 and the collector unit 122, and a plurality of drift tubes (drift holes) 132 that axially communicate the plurality of cavity resonators 131. The cavity resonator 131 is a coaxial cylinder TMmn0 mode (m.gtoreq.0, n.gtoreq.1), and in this embodiment, a coaxial cylinder TM010 mode is used. That is, the plurality of drift tubes 132 communicating with the cavity resonator 131 are arranged so as to face each other on the central axes of the plurality of cathodes 127 of the electron gun section 120 and so as to be aligned at equal intervals on the same circumference having a predetermined radius from the central axis 112 of the klystron main body 111, and pass through the electron beams from the cathodes 127. Further, the center of the drift tube 132 is provided at the peak position of the electric field intensity in the radial direction of the cavity resonator 131.

The plurality of cavity resonators 131 are each configured with an input cavity 133 into which a high frequency is input from the input circuit portion 123, a plurality of intermediate cavities 134, and an output cavity 135 into which an amplified high frequency is output to the output circuit portion 124, in order from the electron gun portion 120 toward the collector portion 122. The intermediate cavity 134 includes an intermediate cavity 134 of a fundamental cavity resonator structure (rd/rc=0.23) and at least one intermediate cavity 134 of a coaxial harmonic cavity resonator structure (rd/rc=0.47) having a double resonant frequency. The coaxial harmonic cavity resonator structure (rd/rc=0.47) having the resonance frequency of twice improves the quality of the bunching and improves the conversion efficiency to high frequencies without extending the length of the interaction portion 121 by efficiently gathering electrons located outside the bunching of electron beams.

Fig. 19A, 19B, and 20 show a cavity resonator 131 as a harmonic cavity resonator. The cavity resonator 131 has a cylindrical or annular cavity 136 centered on the central axis 112. The inner surfaces of the cavity 136, which are opposite to each other in the axial direction, protrude with end portions 137, respectively, and the end portions 137 communicate with the plurality of drift tubes 132. The end 137 is provided in a ring shape protruding in the circumferential direction of the cavity 136 at a radially central position of the cavity 136. A gap portion 138 of a predetermined interval d11 communicating with the drift tube 132 is formed between axially opposite end portions 137.

The axially opposite end 137 is provided with a cavity voltage correction portion 139 for correcting the cavity voltage. The cavity voltage correction portion 139 is provided at a position of the end 137 corresponding to the circumferential direction of the cavity 131. The cavity resonator voltage correction section 139 is formed of groove sections 140 recessed from the surface of the end section 137 at both side positions in the circumferential direction around the drift tube 132. The groove 140 is provided along the circumferential direction of the cavity resonator 131 so as to communicate with the drift tube 132 and to communicate with the drift tube 132 adjacent in the circumferential direction. The gaps d12, d13, and d14 of the gap portions 138 at the positions of the end portions 137 corresponding to the circumferential direction of the cavity resonator 131 are made larger than the gap d11 of the gap portions 138 at the positions of the end portions 137 corresponding to the radial direction of the cavity resonator 131 by the cavity resonator voltage correction portion 139.

The recess amount of the groove 140 is largest at a position in the circumferential direction passing through the center of the drift tube 132, and gradually decreases at positions on the radial center side and the outer side of the cavity resonator 131 than at a position in the circumferential direction passing through the center of the drift tube 132. The interval of the gap portions 138 between the groove portions 140 of the cavity resonator voltage correction portions 139 facing each other in the axial direction is larger than the interval d11 of the gap portions 138 between the end portions 137, and the intervals d13, d12 of the gap portions 138 gradually decrease as moving from the position in the circumferential direction passing through the center of the drift tube 132 to the position on the radial center side and the outer side of the cavity resonator 131 so that the interval d14 of the gap portions 138 is largest at the position passing through the center of the drift tube 132. Accordingly, the intervals d12, d13, and d14 of the gap portion 138 are changed stepwise, that is, stepwise, by the cavity voltage correction portion 139 provided at the position of the end portion 137 corresponding to the circumferential direction of the cavity 131. The interval between the gap portions 138 may be continuously variable.

A magnetic body 143 for forming a plurality of magnetic field sections is disposed around the klystron body 111 between the anode 128 and the collector pole piece 142 on the collector portion 122 side.

Further, the focusing magnetic field device 113 generates a magnetic field for focusing the electron beam, and is constituted by an electromagnet, for example. The focusing magnetic field device 113 includes a magnetic frame 150 for forming a plurality of magnetic field sections together with the plurality of magnetic bodies 143 of the klystron main body 111, and a plurality of coils 151 arranged in each magnetic field section.

The focusing magnetic field device 113 generates a magnetic field parallel to the tube axis of the klystron body 111 at different magnetic field strengths at respective magnetic field intervals. Two magnetic field intervals are provided from the anode 128 of the klystron body 111 to the input cavity 133. The two magnetic field intervals are matching sections for focusing the electron beam from the cathode 127 and making the electron beam parallel to the tube axis of the klystron body 111 after the electron beam is inputted into the cavity 133.

In addition, the electron beam, which becomes a desired diameter through the matching section, enters the input cavity 133. The phase of the high frequency input to the input cavity 133 accelerates and decelerates electrons to perform velocity modulation, and density modulation in which electrons are accelerated and decelerated during traveling in a uniform electric field are respectively accumulated, so that electrons are clustered. The clustered electrons are gradually intensified by the self-induced high frequency electric field in the plurality of intermediate cavities 134. The clustered electrons induce a strong alternating electric field while passing through the output cavity 135, thereby outputting amplified high power high frequency from the output cavity 135 to the outside.

In addition, the input circuit portion 123 inputs and guides a high frequency from the outside to the input cavity 133.

The output circuit portion 124 includes an output window 162 for outputting the amplified high frequency to the outside, and an output waveguide 163 for guiding the high frequency output from the output cavity 135 to the output window 162.

In general, in a multibeam klystron, the ratio of beam current to beam voltage, which is called the coefficient of conductivity per single electron beam, can be controlled to be low by a plurality of cathodes and a plurality of drift tubes, and the total coefficient of conductivity can be set to a large value. It is known in the art that the smaller the coefficient of flow conductivity per single electron beam, the higher the output conversion efficiency of the multibeam klystron, and that the multibeam klystron can achieve high operating efficiency operation at low operating voltages as compared to the single beam klystron.

For example, in a multibeam klystron having a peak output exceeding megawatts, cathodes are arranged at equal intervals on a circumference around the klystron tube axis, holes (drift holes) as drift tubes are provided on the center axis of each cathode, and by arranging cavity resonators as cylinders concentric with the circle on which the TM010 mode cathode is arranged, there is an L-band 10MW klystron which is a coaxial cavity resonator in which the electric field strength in the axial direction in the cavity resonator on the axis of the drift tube (i.e., the axis of the electron beam) is maximized.

The multibeam klystron design is characterized by axisymmetric electromagnetic field distribution with respect to the axis of each electron beam, and by interaction of the electromagnetic field with the electron beam, which is equal and axisymmetric with respect to each electron beam, high efficiency operation is achieved.

As a design of a multi-beam klystron for reducing the operating voltage, it is considered to use a plurality of electron beams having relatively high inductance per single electron beam, thereby increasing the total inductance. The low operating voltage design can shorten the insulation distance at the electron gun electrode, and further, since the traveling speed of electrons becomes slow, the length of the electron gun section and the length of the interaction section become short, there is also an advantage of downsizing.

The multi-beam klystron having a high inductance per single electron beam increases the current per single electron beam as compared to the multi-beam klystron having a low inductance, and thus the focusing magnetic field strength for focusing the electron beam increases. To improve this, it is effective to increase the diameter of the electron beam so as to reduce the current density of the electron beam.

The TM0n0 mode in the coaxial cavity resonator varies in electric field strength in the radial direction but is constant in electric field strength in the circumferential direction in the cavity resonator in the absence of the drift tube. The drift tube through which the electron beam passes is typically placed at a radial position at a position where the electric field strength in the axial direction is maximum.

The acceleration and deceleration of the electron beam are performed by taking into account the cavity resonator voltage of the beam coupling coefficient, which is a value obtained by multiplying the voltage obtained by integrating the electric field intensity on the axis of travel of the electron beam by the beam coupling coefficient obtained by the travel angle of the electron beam.

The electric field intensity distribution has the same tendency as described above even in the presence of the drift hole, and the cavity resonator voltage in the circumferential direction of the cavity resonator is substantially constant, but the cavity resonator voltage decreases when it is separated from the peak position of the electric field in the radial direction. Therefore, when the diameter of the drift tube is small relative to the wavelength of the resonance frequency of the cavity resonator, electrons are accelerated and decelerated by the substantially uniform cavity resonator voltage, but when the diameter of the drift tube is large and the variation of the radial cavity resonator voltage is large, acceleration and deceleration of electrons are uneven, the electron beam bunching becomes uneven and asymmetric, and the orbit of the electron beam is changed and the operation efficiency is lowered. This effect becomes remarkable when the ratio (rd/rc) of the diameter of the drift tube to the cutoff diameter of the TE11 mode of the resonance frequency of the cavity resonator exceeds about 0.2 based on the relationship between the diameters of the cavity resonator and the drift tube, and may occur in the cavity resonator above the S-band for a multibeam klystron outputting several megawatts of electric power.

Therefore, in the present embodiment, the distribution of the cavity resonator voltage is equalized in consideration of the coupling coefficient with the electron beam, which is an essential parameter concerning the electron beam grouping, rather than the electric field intensity in the gap portion 138 of the cavity resonator 131.

In addition, the following equation 1 represents a cavity voltage including a coupling coefficient of the cavity 131. Equation 2 below represents the coupling coefficient k. Here, fc is the resonance frequency of the cavity resonator 131, and ve is the electron velocity.

[ mathematics 1]

V _{cav·e，line} ＝∫ _line E _z (r, z). Cos (kz) dz … formula 1

[ math figure 2]

The fifth embodiment can realize equalization of the distribution of the cavity resonator voltage by the cavity resonator voltage correction section 139. Regarding the fifth embodiment including the cavity resonator voltage correction section 139, a perspective view of a part of the cavity resonator 131 is shown in fig. 20, an electric field intensity distribution diagram around the drift tube 132 of the cavity resonator 131 is shown in fig. 21, a graph showing a relationship between a normalized radius centered on the axis of the drift tube 132 of the cavity resonator 131 and a normalized axial electric field intensity is shown in fig. 22, a graph showing a relationship between an on-axis position of each cavity resonator voltage evaluation axis of the cavity resonator 131 and a normalized axial electric field intensity is shown in fig. 23, and a graph showing normalized cavity resonator voltages taking into consideration the beam coupling coefficients of the cavity resonator 131 with respect to the fifth embodiment and the comparative example two is shown in fig. 24. Further, regarding the second comparative example in which the surface of the end 137 is completely flat and does not include the cavity resonator voltage correction section 139, a perspective view of a part of the cavity resonator 131 is shown in fig. 30, a graph showing a relationship between the normalized radius and the normalized axial electric field intensity centered on the axis of the drift tube 132 of the cavity resonator 131 is shown in fig. 31, and a graph showing a relationship between the on-axis position of each cavity resonator voltage evaluation axis of the cavity resonator 131 and the normalized axial electric field intensity is shown in fig. 32. In fig. 22, the electric field intensity distribution of the fifth embodiment is shown by a solid line, and the electric field intensity distribution of the second comparative example is shown by a broken line. The cavity resonator voltage evaluation axes of fig. 23 and 32 include an axis at the center of the drift tube 132, an axis on the circumference of 70% of the diameter of the drift tube 132, which is the outermost diameter of the electron beam, an axis on the diameter side of 70% of the diameter of the drift tube 132, and an axis between the circumference and the diameter side of 70% of the diameter of the drift tube 132.

In the case of the second comparative example, as shown in fig. 24, the distribution of the cavity resonator voltages on the peripheral side and the radial side was non-axisymmetric with respect to the axis of the electron beam, and the variation of the cavity resonator voltages on the peripheral side and the radial side was 31%. The energy dispersion in the electron clusters accelerated and decelerated by the cavity resonator voltage having a large variation increases, and the operation efficiency decreases, resulting in a decrease in the output conversion efficiency.

In order to operate the multibeam klystron 110 efficiently, it is effective to accelerate and decelerate electrons with respect to the cavity voltage of the cavity resonator 131 that interacts with the electron beam being equal to the electron beam (a distribution in which the deviation of the cavity resonator voltage, which includes the effect of the traveling angle of the electron beam that interacts with the electron beam, is small in the region where the electron beam passes through at the space between the empty resonators).

In the in-line TM010 mode, in the absence of a drift hole, the electric field intensity at the same radial position is the same value regardless of the circumferential phase, but the radial distribution is a mountain-shaped distribution having a peak electric field intensity.

Therefore, the value of the distribution of the cavity resonator voltage on the circumference of the electron beam diameter concentric with the drift tube 132, which is the range of each electron beam, in the radial direction of the cavity resonator 131 is lower than the value in the circumferential direction. When the ratio of the diameter of the drift tube 132 to the wavelength of the cavity resonance frequency increases, the difference between the cavity resonator voltage in the circumferential direction and the cavity resonator voltage in the radial direction of the cavity resonator 131 that interacts with the electron beam increases.

In order to correct the uneven distribution of the cavity voltage at the cavity 131 (harmonic cavity resonator), it is effective to widen the interval of the gap portion 138 on the higher voltage side, narrow the interval of the gap portion 138 on the lower voltage side, and change the distribution of the cavity voltage taking into consideration the coupling coefficient with the electron beam in the drift tube 132.

The electric field intensity distribution in the axial direction of the electron beam is changed by the difference in the interval of the gap portions 138 of the cavity resonator 131, whereby the traveling angle of electrons is adjusted so that the cavity resonator voltage can be controlled.

In the case of the fifth embodiment, the gap 138 in the region of the drift tube 132 where the cavity voltage is high is widened by the cavity voltage correction unit 139, and therefore, the electric field intensity distribution in the axial direction of the electron beam is controlled so that the cavity voltage distribution is approximately axisymmetric with respect to the central axis of the drift tube 132. Therefore, as shown in fig. 24, the variation in the cavity resonator voltage can be improved from 31% to 9% in the second comparative example. By accelerating and decelerating electrons by the cavity resonator voltage with small deviation, efficiency degradation can be prevented.

In this way, by correcting the non-axisymmetry of the cavity voltage in the circumferential direction and the radial direction of the cavity resonator 131 so that the distribution of the cavity resonator voltage approaches axisymmetry with respect to the axis of the electron beam, it is possible to reduce energy dispersion in the cluster of electrons accelerated and decelerated by the cavity resonator voltage, suppress a decrease in the operation efficiency, and improve the output conversion efficiency.

Next, a sixth embodiment is shown in fig. 25 to 29.

Fig. 25 shows a perspective view of a part of the cavity resonator 31, fig. 26 shows an electric field intensity distribution diagram around the drift tube 132 of the cavity resonator 131, fig. 27 shows a graph showing a relationship between a normalized radius centered on the axis of the drift tube 132 of the cavity resonator 131 and a normalized axial electric field intensity, fig. 28 shows a graph showing a relationship between an on-axis position of each cavity resonator voltage evaluation axis of the cavity resonator 131 and a normalized axial electric field intensity, and fig. 29 shows a graph showing normalized cavity resonator voltages taking into consideration beam coupling coefficients of each cavity resonator voltage evaluation axis of the cavity resonator 131 with respect to the sixth embodiment and the third comparative example. In fig. 27, the electric field intensity distribution of the present embodiment is shown by a solid line, and the electric field intensity distribution of the third comparative example is shown by a broken line. Further, the cavity resonator voltage evaluation axis of fig. 28 is as described above.

As shown in fig. 25, the cavity resonator 131 is a coaxial harmonic cavity resonator structure (rd/rc=0.47). The end 137 of the cavity resonator 131 is provided for each drift tube 132 in a cylindrical shape protruding from the periphery of the drift tube 132 into the cavity.

The cavity voltage correction unit 139 is formed of groove portions 140 provided at the end portions 137 corresponding to the positions on both sides in the circumferential direction around the drift tube 132.

Further, the gap portion 138 is formed to have a larger interval than the end portion 137 by the groove portion 140 of the electric field correction portion 139, so that the cavity voltage in the circumferential direction with respect to the axis of the drift tube 132 is increased, and the cavity voltages in the circumferential direction and the radial direction are brought close to each other, whereby the distribution of the cavity voltages can be axisymmetric with respect to the axis of the electron beam.

In the case where the groove 140 of the cavity voltage correction portion 139 is not provided in the end portion 137, as shown in fig. 29, the distribution of the cavity voltage on the peripheral side and the radial side is non-axisymmetric with respect to the axis of the electron beam, and the deviation of the cavity voltage on the peripheral side and the radial side is 25%. The large deviation of the cavity resonator voltage increases energy dispersion in the clusters of electrons accelerated and decelerated, and the operation efficiency decreases, resulting in a decrease in output conversion efficiency.

In the case of the sixth embodiment, the variation in the cavity resonator voltage can be improved from 25% to 6% in the third comparative example. By accelerating and decelerating electrons by the cavity resonator voltage with small deviation, efficiency degradation can be prevented.

Further, fig. 33 to 36 show a comparative example four. Fig. 33 shows a perspective view of a part of the cavity resonator 131, fig. 34 shows a graph showing a relationship between normalized radius and normalized axial electric field intensity centered on the axis of the drift tube 132 of the cavity resonator 131, fig. 35 shows a graph showing a relationship between the on-axis position of each cavity resonator voltage evaluation axis of the cavity resonator 131 and normalized axial electric field intensity, and fig. 36 shows a graph showing normalized cavity resonator voltages taking into consideration the beam coupling coefficient of each cavity resonator voltage evaluation axis of the cavity resonator 131 with respect to comparative examples two and four. Further, the cavity resonator voltage evaluation axis of fig. 35 is as described above.

The cavity resonator 131 of the fourth comparative example is a coaxial harmonic cavity resonator structure (rd/rc=0.47).

The electric field correction portion 170 protrudes from the end portion 137 in the radial direction of the cavity resonator 131, and makes the interval of the gap portion 138 smaller and increases the electric field intensity distribution so that the electric field intensity distribution becomes axisymmetric with respect to the axis of the electron beam.

When the ratio (rd/rc) of the diameter of the drift tube 132 to the cutoff diameter in the TE11 mode at the resonance frequency of the cavity resonance exceeds about 0.35 times, preferably exceeds 0.4 times, the drop in the cavity resonator voltage at the both radial end sides of the drift tube 132 is large, and therefore, if the electric field strength at only the center of the gap portion 138 is set to the same extent as in comparative example four, the effect of improving the mass of the electron beam cluster is insufficient. Further, an example in which the ratio of the diameter of the drift tube 132 to the cut-off diameter exceeds 0.35 times, preferably exceeds 0.4 times, may be found in a case where a harmonic cavity resonator is used in a multibeam klystron having an S-band or higher, a cavity resonator in a multibeam klystron having an X-band or higher, or the like.

As shown in fig. 36, in the fourth comparative example, the variation in the cavity resonator voltage between the peripheral side and the radial side can be improved from 31% to 27% in the second comparative example, but the improvement effect is low. In the fifth embodiment, the variation in the cavity resonator voltage is greatly improved from 31% of the second comparative example to 9%. By accelerating and decelerating electrons by the cavity resonator voltage with small deviation, efficiency degradation can be prevented.

Further, a perspective view of a part of the cavity resonator 131 of the comparative example five is shown in fig. 37, a perspective view of a part of the cavity resonator 131 of the comparative example six is shown in fig. 38, and a table of normalized cavity resonator voltages regarding the beam coupling coefficients of each cavity resonator voltage evaluation axis of the cavity resonator 131 of the comparative example five and the comparative example six is shown in fig. 39. Further, the cavity resonator voltage evaluation axis of fig. 39 is as described above.

The cavity resonator 131 of the fifth comparative example in fig. 37 is a structure in which electric field intensity is not corrected, and is a fundamental cavity resonator structure (rd/rc=0.23), like the second comparative example in fig. 30. The cavity resonator 131 of the sixth comparative example in fig. 38 has the electric field correction unit 170 in the same manner as the fourth comparative example in fig. 33, and has a fundamental cavity resonator structure (rd/rc=0.23).

In the fundamental cavity resonator in which the diameter ratio rd/rc of the drift tube 132 is about 0.2 as in the fifth and sixth comparative examples, the electric field intensity at the center of the gap portion 138 is substantially equalized by the correction of the electric field correction portion 170, and the variation in the cavity resonator voltage between the peripheral side and the radial side is 6% and 5%, but in the harmonic cavity resonator in which rd/rc is more than 0.35 times and preferably more than 0.4 times as in the fourth comparative example, the variation in the cavity resonator voltage between the peripheral side and the radial side is as large as 27% even when the correction is performed by the electric field correction portion 170.

Therefore, as in the fifth and sixth embodiments, by correcting the non-axisymmetry of the cavity voltage in the circumferential and radial directions of the cavity resonator 131 so that the distribution of the cavity resonator voltage approaches axisymmetry with respect to the axis of the electron beam, it is possible to reduce the energy dispersion in the cluster of electrons accelerated and decelerated by the cavity resonator voltage, suppress the reduction in the operation efficiency, and improve the output conversion efficiency.

Further, in the case where there is a tendency that the electric field intensity distribution is not axisymmetric with respect to the axis of the electron beam, that is, the diameter of the drift tube 132 is 0.35 times or more the cutoff diameter of the TE11 mode at the resonance frequency of the cavity resonator 131 and the diameter of the drift tube 132 is relatively large with respect to the wavelength at the resonance frequency, it is possible to correct the non-axisymmetry of the distribution of the cavity resonator voltage in the circumferential direction and the radial direction of the cavity resonator 131 and axisymmetric the cavity resonator voltage with respect to the axis of the electron beam.

While the embodiments of the present invention have been described above, these embodiments are merely examples and are not intended to limit the scope of the present invention. These novel embodiments can be implemented in various other ways, and various omissions, substitutions, changes, and the like can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and their equivalents.

Claim (modification according to treaty 19)

1. A klystron device comprising:

a klystron body having an electron gun section that generates an electron beam, a collector section that captures the electron beam, a plurality of cavity resonators disposed between the electron gun section and the collector section, and a plurality of drift tubes that communicate with the plurality of cavity resonators in an axial direction; and a focusing magnetic field device which focuses the electron beam, characterized in that,

the cavity resonator has end portions that are axially opposed to each other to form a gap portion that communicates with the drift tube,

at least one of the cavity resonators has an electric field correction section at a part of the end section, the electric field correction section making a spacing of the gap section different from a spacing at the end section,

the electric field correction part

The gap portion is made smaller by protruding from the end portion in the radial direction of the cavity resonator, or,

the gap portion is recessed from the end portion in the circumferential direction of the cavity resonator so that the interval of the gap portion becomes larger, or,

The gap portion is made smaller in a radial direction of the cavity resonator by protruding from the end portion, and is made larger in a circumferential direction of the cavity resonator by being recessed from the end portion.

2. A klystron device as defined in claim 1, wherein:

the electric field correction unit is provided at a position of the end portion separated from the drift tube.

3. A klystron device as defined in claim 1, wherein:

the cavity resonator is a coaxial TM010 mode, and a plurality of the drift tubes are located on a circumference concentric with the cavity resonator.

4. A klystron device as defined in claim 3, wherein:

the diameter of the drift tube is 0.2 times or more of the cutoff diameter of the TE11 mode at the resonance frequency of the cavity resonator.

5. A klystron device comprising:

at least one of the cavity resonators has a cavity resonator voltage correction section provided at a position of the end section corresponding to a circumferential direction of the cavity resonator so that a gap of the gap section becomes larger.

6. A klystron device as defined in claim 5, wherein:

the cavity resonator voltage correction section maximizes the interval of the gap sections at positions in the circumferential direction passing through the center of the drift tube, and makes the interval of the gap sections at positions on the radial center side and the outer side of the cavity resonator smaller than the interval of the gap sections at positions in the circumferential direction passing through the center of the drift tube.

7. A klystron device as defined in claim 6, wherein:

the cavity resonator voltage correction section changes the interval of the gap section stepwise.

8. A klystron device as defined in claim 7, wherein:

9. A klystron device as defined in claim 8, wherein:

the diameter of the drift tube is 0.35 times or more of the cutoff diameter of the TE11 mode at the resonance frequency of the cavity resonator.

10. A klystron device as defined in claim 5, wherein:

11. A klystron device as defined in claim 10, wherein:

Claims

1. A klystron device comprising:

at least one of the cavity resonators has an electric field correction section at a part of the end section, the electric field correction section making a spacing of the gap section different from a spacing at the end section.

2. A klystron device as defined in claim 1, wherein:

3. A klystron device as defined in claim 2, wherein:

the electric field correction portion protrudes from the end portion in a radial direction of the cavity resonator so that a gap between the gap portions is reduced.

4. A klystron device as defined in claim 2, wherein:

the electric field correction portion is recessed from the end portion in a circumferential direction of the cavity resonator so that a spacing of the gap portion becomes larger.

5. A klystron device as defined in claim 2, wherein:

the electric field correction portion protrudes from the end portion in a radial direction of the cavity resonator so that an interval of the gap portion becomes smaller, and is recessed from the end portion in a circumferential direction of the cavity resonator so that an interval of the gap portion becomes larger.

6. A klystron device as defined in claim 1, wherein:

7. A klystron device as defined in claim 1, wherein:

8. A klystron device as defined in claim 1, wherein:

9. A klystron device as defined in claim 1, wherein:

10. A klystron device as defined in claim 9, wherein:

11. A klystron device comprising:

12. A klystron device as defined in claim 11, wherein:

13. A klystron device as defined in claim 12, wherein:

14. A klystron device as defined in claim 13, wherein:

15. A klystron device as defined in claim 14, wherein:

16. A klystron device as defined in claim 11, wherein:

17. A klystron device as defined in claim 16, wherein: