JP2005063894A - Radiological linac and electron beam generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small linac for radiotherapy capable of continuously changing the energy of an electron beam and a radiotherapy apparatus using the same.
SOLUTION: Two acceleration tubes 6 and 7 connected in series for accelerating an electron beam are provided, and energy of the electron beam is adjusted by adjusting a relative phase of a high frequency input to the acceleration tubes 6 and 7. A linac 4 is configured by providing a phase shifter 11 for adjusting the angle. At this time, the accelerating tubes 6 and 7 are configured to operate at a high frequency in the frequency of the X band, and are composed of permanent magnets for deflecting the electron beam trajectory 180 degrees between the accelerating tubes 6 and 7. The electron beam deflection unit 8 is provided to reduce the size.
[Selection] Figure 1

Description

  The present invention relates to an electron beam generating device that generates an electron beam, and radiation that includes the electron beam generating device and generates an X-ray by irradiating an X-ray target with the electron beam generated by the electron beam generating device. The present invention relates to a small radiotherapy linac suitable for use in therapy.

Conventionally, in radiotherapy, X-rays generated by irradiating an X-ray target with electrons accelerated using an electron beam accelerator are irradiated to an affected area, or electrons accelerated using an electron beam accelerator are used. Treatment is performed by irradiating the affected area directly. As such an accelerator for radiation therapy, a linac (linear accelerator) is often used.
Many radiotherapy linacs have been used in which the high frequency input to the accelerating tube is included in the S-band of about 3 GHz. However, these linacs have been disclosed in Non-Patent Document 1 and Non-Patent Document 2 in recent years. As described above, attempts have been made to reduce the size of the linac by using a higher frequency in the C-band or X-band. A conventional linac for radiotherapy having a frequency in the S-band is, for example, a linac body that is placed parallel to the rotation axis, rotates around the rotation axis while being parallel to the rotation axis, and is placed on a bed laid near the rotation center. An electron beam or an X-ray is irradiated from all directions toward an affected part of a lying patient. However, since the rotation axis is fixed at this time, radiation irradiation is limited to a plane perpendicular to the rotation axis. The radiotherapy apparatus having such a configuration is also called a rotating gantry. In contrast, for example, the linac for radiation therapy disclosed in Non-Patent Document 2 is miniaturized by a high frequency whose frequency is in the X band, and the linac is attached to the tip of an arm of an industrial robot. However, the present invention is not limited to a single plane as in the prior art, and X-rays can be irradiated from various directions.
E. Tanabe, “Medical application of ultra-small linac” Linac Study Group, 1998 Takehiro Inoue, Toshihiko Inoue “Narrow Beam Radiation Therapy” Cancer Clinical 43, 221-225, 1997

  However, the conventional linac for radiotherapy has a problem that the energy can be adjusted only in stages. In other words, in these linacs, the resonance state of the accelerating cell of the accelerating tube is controlled, and the energy of the electrons accelerated depending on which accelerating cell is used among a plurality of accelerating cells is set. Therefore, for example, in order to obtain X-rays that match the depth of the affected area, even if the energy of the accelerated electrons is changed, the energy is only in the unit of energy corresponding to one acceleration cell when the acceleration cell is turned on / off. Cannot be increased or decreased.

  In view of the above circumstances, the present invention provides an electron beam generator capable of continuously changing the energy of an electron beam and an X-ray generator using the electron beam generator, particularly a linac for radiotherapy. It is in. At this time, the linac for radiotherapy must be small in size so that it can be used around the affected area.

  In order to solve this problem, a radiotherapy linac according to a first aspect of the present invention for generating an electron beam for radiotherapy has a plurality of accelerating tubes connected in series for accelerating the electron beam. The electron beam energy adjusting means adjusts the energy of the electron beam by adjusting the relative phase of the high frequency input to at least two of the plurality of accelerator tubes. .

  With this configuration, the energy of the electron beam is continuously adjusted by continuously adjusting the relative phase of the high frequency input to the at least two accelerator tubes using the electron beam energy adjusting means. Can be adjusted. That is, the phase of the high frequency input to the at least two accelerator tubes is relatively adjusted so that the phase angle between the electron beam bunch and the electric field in the accelerator tube is different. The electric field received when this electron beam bunch passes through the other acceleration tube can be set continuously against the electric field received in the acceleration cavity when passing through one of the acceleration tubes. The energy of the electron beam accelerated by these electric fields can be set continuously.

As an example, consider a case where the relative phase of a high frequency input to, for example, two accelerator tubes among a plurality of accelerator tubes is adjusted. When the phase angle between the electron beam and the electric field is θ ₁ in one of the two accelerating tubes, the electron beam has this accelerating tube (the length L ₁ of the accelerating tube and the maximum electric field strength E ₁ . The energy gain V ₁ obtained when passing through

When the phase angle between the electron beam and the electric field is θ ₂ in the other accelerator tube, this electron beam passes through this accelerator tube (the length L _{2 of the} accelerator tube and the maximum electric field strength E ₂ ). energy gain V ₂ obtained when the generally:

Therefore, the energy gain V ₁ + V ₂ that the electron beam obtains when passing through the two accelerator tubes continuously changes the values of the phase angles θ ₁ and θ ₂ as can be seen from the above formula. Can be adjusted to take a continuous value. As an example only, when changing the energy gain V ₁ + V ₂ , the phase of either θ ₁ or θ ₂ is fixed to be, for example, cos θ ₁ = 1 (or cos θ ₂ = 1). Thus, the other phase may be changed and adjusted. In particular, when the same high frequency power supply is used for the two accelerator tubes, the high frequency is branched and the high frequency is introduced into each of the two accelerator tubes. At this time, the lead is input to the accelerator tube whose phase is to be changed. A phase shifter (also referred to as a phase shifter in the present specification) for continuously adjusting the phase is inserted into the wave tube, and a relative phase or phase angle difference (θ ₁ −θ ₂ ) is inserted. ) May be adjusted continuously. In this case, the phase shifter substantially serves as an electron beam energy adjusting means. The electron beam energy adjusting means is not limited to such a phase shifter, and includes any means that can be easily implemented by those skilled in the art, such as adjusting the phase angle between the electron beam and the electric field in the two accelerator tubes. Needless to say,

  As described above, the case where the relative phase of the high frequency input to the two accelerator tubes is adjusted has been described here. However, the present invention is not limited to the two accelerator tubes, and an arbitrary number of accelerator tubes among the plurality of accelerator tubes. It is also possible to adjust the phase of the electron beam bunch and the electric field in these accelerating tubes to be different by relatively adjusting the phase of the high frequency input to It is possible for the same reason.

  According to a preferred embodiment of the radiological linac according to the first aspect of the present invention, between the at least two accelerating tubes of the plurality of accelerating tubes in order to reduce the size of the radiotherapy linac having a plurality of accelerating tubes. On the orbit of the electron beam, an electron beam deflecting unit that deflects the orbit of the electron beam by a magnetic field is provided. Since the electron trajectory in the accelerating tube is substantially straight, connecting a plurality of accelerating tubes in series results in a structure in which the accelerating tubes are arranged in a straight line, and an increase in length is unavoidable. Therefore, according to the present invention, an electron beam deflecting unit that deflects the orbit of the electron beam by a magnetic field is provided between at least two accelerator tubes, so that the overall length can be shortened as much as possible. At this time, the electron beam deflection unit disposed between the accelerating tubes may be configured to deflect the electron beam trajectory at a predetermined angle once, or may be configured to deflect a predetermined angle a plurality of times. May be.

  In the radiological linac according to the first aspect of the present invention, the electron beam deflection section is preferably provided so as to deflect the trajectory of the electron beam by 180 °. With this configuration, at least two long accelerating tubes can be arranged in parallel so as to draw a trajectory in which the electron beam makes a U-turn, and the radiotherapy linac can be effectively downsized. .

  According to a particularly preferred embodiment of the radiological linac according to the first aspect of the present invention, the electron beam deflecting unit is configured using a permanent magnet utilizing the remanent magnetization of a ferromagnetic material having a large coercive force. . Therefore, unlike a case where an electromagnet that winds a coil around a magnetic path with a gap and magnetizes the magnetic path by a current flowing through the coil to create a magnetic field in the gap is used for the electron beam deflection unit, a power source and a coil for flowing a current through the coil This eliminates the need for water cooling equipment for coil cooling that suppresses heat generation. Thereby, size reduction of the linac for radiotherapy can be achieved.

  The permanent magnet is preferably a rare earth permanent magnet mainly composed of neodymium (Nd), iron (Fe), and boron (B). As a result, the magnetic field strength is increased, and the radius of curvature of the orbit of the electron beam when deflecting the electron beam can be reduced, so that the linac for radiotherapy can be miniaturized. In particular, when NEOMAX (trademark) of Sumitomo Special Metals is used as an anisotropic sintered magnet mainly composed of neodymium, iron and boron, a magnetic field strength of 4.4 T can be obtained.

  According to the present invention, the linac for radiation therapy having the simplest configuration has only two acceleration tubes. With this configuration, the smallest linac can be obtained while the energy of the electron beam can be continuously changed.

  In particular, according to the present invention, when the high-frequency frequency input to the accelerator tube is a C-band or X-band frequency, the linac is smaller than the conventional accelerator tube having the S-band high-frequency frequency. It is possible to In particular, when the high frequency of the frequency in the X band is used, the size of the acceleration tube can be reduced to about half compared to the case of using the high frequency of the frequency in the S band, so that the high frequency power source and the acceleration tube are integrated. It becomes possible to assemble with. In the case of the conventional S-band accelerator tube, since the high-frequency power source is installed separately from the accelerator tube, the structure of the waveguide between the fixed high-frequency power source and the movable accelerator tube becomes complicated. Although the movable range was limited, according to the present invention, the acceleration tube and the high-frequency power source can be assembled together, and the movable range of the acceleration tube can be expanded.

  In this specification, the electron beam for radiation therapy is not limited to the case where the affected part is irradiated with an X-ray obtained by irradiating the X-ray target such as a metal thin film, but the case where the affected part is directly irradiated with the electron beam. Is also included.

  If the linac for radiotherapy is considered as an electron beam generator for generating an electron beam for irradiating a target for X-ray generation, the present invention is not limited to radiotherapy. Accordingly, the present invention according to the second aspect provides an electron beam generator for generating an electron beam for irradiating a target for X-ray generation, and a plurality of accelerator tubes connected in series for accelerating the electron beam. And an electron beam energy adjusting means for adjusting the energy of the electron beam by adjusting a relative phase of a high frequency input to at least two of the plurality of accelerator tubes. A characteristic electron beam generation apparatus is also included. With this configuration, the energy of the electron beam for irradiating the target for X-ray generation can be continuously changed.

  Further, the configuration of the present invention according to the first aspect described above for reducing the size of the radiotherapy linac is the electron of the present invention according to the second aspect of generating an electron beam for irradiating a target for X-ray generation. It can also be used to reduce the size of the line generator.

  According to a third aspect of the present invention, there is provided an X-ray generation apparatus further comprising: an electron beam generation apparatus that generates an electron beam; and an X-ray target that generates X-rays by irradiation of the electron beam. There is also provided an X-ray generation apparatus characterized in that the generation apparatus is an electron beam generation apparatus according to the second aspect of the present invention. According to such an X-ray generation apparatus, the energy of the electron beam for X-ray generation can be continuously changed and / or the size of the apparatus can be reduced.

  The X-ray generation apparatus according to the third aspect of the present invention can be used for radiotherapy if the wavelength range of X-rays to be generated is set to the X-ray wavelength range used for radiotherapy.

  The present invention further includes, as a fourth aspect, a radiotherapy apparatus for radiotherapy using an electron beam directly or indirectly, including the electron beam generator that generates the electron beam, and the electron beam generator Provides a radiotherapy apparatus which is a radiotherapy linac according to the first aspect of the present invention. According to such a radiotherapy device, the energy of the electron beam can be continuously changed and / or the size of the device can be reduced.

As described above, according to the linac for radiotherapy of the present invention, the energy of the electron beam can be continuously changed and / or the size of the apparatus can be reduced.
Moreover, according to the electron beam generating apparatus of the present invention that generates an electron beam for irradiating the target for X-ray generation, the energy of the electron beam can be continuously changed and / or the size of the apparatus can be reduced. can do.
Further, according to the X-ray generation apparatus of the present invention, the energy of the electron beam for irradiating the X-ray generation target can be continuously changed and / or the size of the apparatus can be reduced.
Further, according to the radiotherapy apparatus of the present invention, the energy of the electron beam can be continuously changed and / or the size of the apparatus can be reduced.

  Hereinafter, the present invention will be described with reference to the drawings.

  FIG. 1 is a view showing a radiotherapy apparatus according to the present invention. The radiotherapy apparatus 1 includes an irradiation head unit 2 that emits X-rays X as radiation, and a robot unit 3 to which the irradiation head unit 2 is attached. In the radiotherapy apparatus 1, the robot unit 3 is arranged on the side of the medical table B where the patient P to be treated lies, and the irradiation head unit 2 is moved by the robot unit 3 so that the patient P is directed from a free direction. X-ray X is configured to be irradiated.

  Here, the robot unit 3 includes an arm unit 3a that supports the irradiation head unit 2, and a robot unit body that drives and controls the arm unit 3a so as to freely set the position of the irradiation head unit 2 by operating the arm unit 3a. 3b. The robot unit 3 has the same configuration as that of an industrial robot, and those skilled in the art can use the robot unit 3 to irradiate the affected part of the patient P with X-rays X from various angles. Since it is obvious that the robot unit 3 is operated, the robot unit 3 will not be described in further detail in this specification. However, it goes without saying that the radiotherapy apparatus according to the present invention includes a configuration in which the robot unit 3 is modified to such an extent that a person skilled in the art can easily conceive.

  The irradiation head unit 2 includes a linac 4 (radiotherapy linac as an electron beam generating apparatus) according to the present invention and a housing 2a that stores the linac 4 and blocks radiation other than that irradiated to the affected area. Yes. The linac 4 includes an electron gun 5 that emits electrons, a first acceleration tube 6 that accelerates electrons emitted from the electron gun 5 to a predetermined energy of about 6 MeV, and the first acceleration tube 6. A second accelerating tube 7 for further accelerating the accelerated electrons, an electron beam deflecting portion 8 provided between the first accelerating tube 6 and the second accelerating tube 7, A high frequency power source 9 for supplying a high frequency to the second acceleration tube 7, a waveguide 10 for guiding a high frequency from the high frequency power source 9 to the first acceleration tube 6 and the second acceleration tube 7, and a high frequency power source 9 A phase shifter 11 (electron beam energy adjusting means) that is inserted into the waveguide leading to the second accelerating tube 7 and shifts the phase of the high frequency is schematically configured.

  Although not shown in detail here, the electron gun 5 has a configuration including an electron gun using a hot cathode type cathode or photocathode, a prebuncher, a buncher, or the like, or uses a high frequency from the hot cathode type cathode or photocathode. It is configured as a high-frequency electron gun that extracts electrons.

  The first acceleration tube 6 for accelerating electrons supplied from the electron gun 5 has an acceleration cavity to which a high frequency having a frequency in the X band is input, and accelerates the electrons to a predetermined energy of about 6 MeV. Is configured to do. A high frequency is sent from the high frequency power supply 9 to the first acceleration tube 6 through the waveguide 10a, and a high frequency is input into the first acceleration tube 6 from a coupling portion (not shown).

  The electron beam deflecting unit 8 provided on the downstream side of the first acceleration tube 6 in the traveling direction of the electron beam is an S pole of a rare earth permanent magnet mainly composed of neodymium (Nd), iron (Fe), and boron (B). And N poles are arranged so as to face each other so that a gap through which an electron beam passes is formed. The electron beam deflecting unit 8 is provided with a size that deflects the trajectory of the electron beam from the first acceleration tube 6 by 180 ° at a time. That is, the electron beam deflecting unit 8 has the first curvature when the radius of curvature of the electron beam orbit determined by the magnetic field strength of the rare earth permanent magnet used and the energy of the electron beam exiting the first accelerator tube is r. The semicircle with the radius r passing through the incident position where the electron beam from the accelerating tube 6 is incident is provided so as to be entirely inside the electron beam deflecting unit 8. Although not shown, a slit is provided on the ideal orbit of the electron beam near the center of the electron beam deflecting unit 8 so that an electron beam having a predetermined energy cannot pass. Further, on the upstream side and the downstream side of the electron beam deflection unit 8 in the traveling direction of the electron beam, for example, beam focusing magnets 8a and 8b for electron beam transfer such as a quadrupole magnet and a deflection electromagnet similarly using permanent magnets, A beam monitor or the like is provided.

  The second accelerating tube 7 is installed so that it is parallel to the first accelerating tube 6 and its center line passes through the electron beam emitting position of the electron beam deflecting unit 8. The second accelerating tube 7 has substantially the same configuration as the first accelerating tube 6 and has an accelerating cavity into which a high frequency having a frequency in the X band is input, and further increases the energy of electrons by about 6 MeV at the maximum. It is configured to let you. A high frequency is sent from the high frequency power supply 9 to the second acceleration tube 7 through the waveguide 10b, and a high frequency is input into the second acceleration tube 7 from a coupling portion (not shown).

  A phase shifter 11 is inserted in the middle of the waveguide 10b, and the electron beams in the first and second accelerator tubes 6 and 7 are taken into consideration while taking into account the difference in length between the waveguide 10a and the waveguide 10b. The relative phase of the high frequency input to the first and second accelerator tubes 6 and 7 is adjusted so that the phase angle between the bunch and the electric field is adjusted. That is, when the phase angle between the electron beam and the electric field in the first accelerating tube 6 is set to θ, the phase shifter 11 changes the phase of the high frequency input to the second accelerating tube 7 to the first acceleration. The phase angle between the electron beam and the electric field in the second accelerating tube 7 is set to θ + Δθ by a continuous arbitrary value Δθ. ing.

  The radiotherapy apparatus 1 of the present invention configured as described above is arranged at a predetermined position by the robot unit 3 so that the X-ray X is appropriately applied to the affected part of the patient P. The electron beam generated from the electron gun 5 is accelerated to a predetermined energy in the first accelerating tube 6 and transferred to the incident position of the electron beam deflecting unit 8 by the beam focusing magnet 8a. Is deflected 180 °. At this time, the electron beam other than the predetermined energy is removed by the slit S. In the initial adjustment stage, the slit S is also used to adjust the energy of the electron beam from the first acceleration tube 6 to a predetermined energy. The electron beam emitted from the electron beam deflecting unit 8 is then transferred to the second acceleration tube 7 by the beam focusing magnet 8b, and is incident on the second acceleration tube. The phase of the high frequency input to the second accelerating tube is shifted relative to the phase of the high frequency input to the first accelerating tube by the phase shifter 11. The phase angle between the electron beam and the electric field is adjusted to be different from the phase angle between the electron beam and the electric field in the first accelerating tube. For example, when the phase angle between the electron beam and the electric field in the first acceleration tube 6 is θ, the phase angle between the electron beam and the electric field in the second acceleration tube 7 is θ + Δθ (Δθ continuous arbitrary Can be adjusted). The energy of the electron beam accelerated by the first accelerating tube 6 depends on cos θ, and the energy of the electron beam further accelerated by the second accelerating tube 7 depends on cos (θ + Δθ). By changing the value of Δθ, the energy of the electron beam accelerated by the first and second acceleration tubes 6 and 7 can be freely adjusted. For example, if Δθ = 0, the electron beam can be accelerated in the second acceleration tube 7 as much as the first acceleration tube 6, and the electron beam is accelerated to 6 MeV by the first acceleration tube 6. In the case of the present embodiment, the final energy of the electron beam is about 12 MeV. If adjusted to θ + Δθ = π / 2, acceleration is not performed in the second accelerating tube 7 and the final electron beam energy is about 6 MeV.

  As described above, the electron beam R is generated by the linac 4, and the electron beam R is irradiated onto the X-ray generation target 12 made of a thin film metal, thereby generating the X-ray X used for radiation therapy. The X-ray X is shaped into a beam shape appropriately matched to the size of the affected part by a collimator or the like not shown here.

  As described above, according to the present embodiment, the energy of an electron beam for generating X-rays used for radiation therapy can be freely adjusted. And since the high frequency used for the 1st and 2nd acceleration tubes 6 and 7 is made into the frequency of X band zone, the 1st and 2nd acceleration tubes 6 and 7 can be miniaturized. Therefore, the first and second acceleration tubes 6 and 7 and the high-frequency power source 9 can be integrated into the irradiation head unit 2, and the irradiation head can be compared with the conventional configuration in which the high-frequency power source is provided separately. The movable range of the part 2 can be expanded. In addition, since the electron beam trajectory 8 is configured to deflect the electron beam trajectory by 180 °, the first and second acceleration tubes 6 and 7 can be arranged in parallel, and the linac 4 can be made compact. Can do. At this time, the electron beam deflecting unit 8 is composed of a rare earth permanent magnet mainly composed of neodymium (Nd), iron (Fe), and boron (B), has a large magnetic field strength, and makes the electron beam deflecting unit 8 small. In addition to being able to be manufactured, a power source, a cooling system, and the like necessary for a conventional electromagnet are unnecessary, which is effective for downsizing the linac.

  In addition, in the radiotherapy apparatus 1 by this invention shown in FIG. 1, although it was set as the structure which uses the X-ray X as a radiation, it can also be comprised so that an electron beam may be used for treatment auxiliary.

  In addition, the number of acceleration tubes is not limited to two as in the present embodiment, and a plurality of three or more acceleration tubes are used, or the electron beam deflection unit is configured of a plurality of deflection magnets in consideration of electron beam optics. The above-described radiation therapy apparatus, in particular, the linac can be modified within a range that can be easily conceived by those skilled in the art.

  In the present embodiment, the radiotherapy apparatus is configured to irradiate the patient P with the X-ray X. However, an electron beam or an X-ray other than the patient can be easily conceived by those skilled in the art. You may change an apparatus so that it may irradiate. Thus, although the present invention is most preferably used for therapy, it should be understood that the present invention need not be limited to use only for therapy.

  The energy of the electron beam can be freely adjusted by the electron beam energy adjusting means, and can be effectively used particularly for radiation therapy. Moreover, it can be configured in a small size, and the handling is simple due to the small turning.

It is the schematic block diagram which showed the radiotherapy apparatus and linac by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Radiation therapy apparatus 2 ... Irradiation head part 2a ... Housing 3 ... Robot part 3a ... Arm part 3b ... Robot part main body 4 ... Linac (electron beam generator)
5 ... Electron gun 6 ... First accelerator tube (including electron gun)
DESCRIPTION OF SYMBOLS 7 ... 2nd acceleration tube 8 ... Electron beam deflection | deviation part 8a, 8b ... Beam focusing magnet 9 ... High frequency power supply 10 ... Waveguide 10a ... It connects with a 1st acceleration tube Waveguide 10b ... Waveguide connected to the second acceleration tube 11 ... Phase shifter 12 ... Target B ... Medical table P ... Patient R ... Electron beam X ... X-ray

Claims (14)

  A radiotherapy linac for generating X-rays and electron beams for radiation therapy, comprising a plurality of accelerator tubes connected in series for accelerating the electron beams, and at least two of the plurality of accelerator tubes A radiotherapy linac comprising an electron beam energy adjusting means for adjusting energy of the electron beam by adjusting a relative phase of a high frequency inputted to the radio frequency. The radiotherapy linac according to claim 1,
An radiac for radiotherapy, wherein an electron beam deflecting section for deflecting the trajectory of the electron beam by a magnetic field is provided between at least two of the plurality of accelerator tubes.   3. The radiotherapy linac according to claim 2, wherein the electron beam deflection unit is provided so as to deflect a trajectory of the electron beam by 180 degrees. In the linac for radiotherapy according to claim 2 or 3,
The electron beam deflecting unit is configured by using a permanent magnet. The linac for radiotherapy according to claim 4,
A linac for radiotherapy characterized in that the permanent magnet of the electron beam deflection section is a rare earth permanent magnet mainly composed of neodymium, iron, and boron.   The linac for radiotherapy according to any one of claims 1 to 5, wherein the linac for radiotherapy has two acceleration tubes. The linac for radiation therapy according to any one of claims 1 to 6,
A radiotherapy linac characterized in that the frequency of the high frequency input to the accelerating tube is a C-band or X-band frequency. In an electron beam generator for generating an electron beam for irradiating a target for X-ray generation,
A plurality of accelerating tubes connected in series for accelerating the electron beam, and adjusting the relative phase of a high frequency input to at least two of the accelerating tubes; And an electron beam energy adjusting means for adjusting the energy of the electron beam. In the electron beam generating apparatus according to claim 8,
An electron beam generating apparatus characterized in that an electron beam deflecting unit that deflects the orbit of the electron beam by a magnetic field is provided between at least two of the plurality of accelerator tubes. In the electron beam generating apparatus according to claim 9,
The electron beam generating apparatus according to claim 1, wherein the electron beam deflecting unit is provided to deflect a trajectory of the electron beam by 180 °. In the electron beam generating apparatus according to claim 9 or 10,
The electron beam generator is configured by using a permanent magnet. The electron beam generating apparatus according to claim 11,
The electron beam generator according to claim 1, wherein the permanent magnet of the electron beam deflection unit is a rare earth permanent magnet mainly composed of neodymium, iron, and boron. In the electron beam generating device according to any one of claims 8 to 12,
An electron beam generator having two acceleration tubes. The electron beam generating apparatus according to any one of claims 8 to 13,
2. The electron beam generating apparatus according to claim 1, wherein the high frequency is a frequency in a C band or an X band.

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