Superconducting cryomodule

Abstract

To provide a superconduction cryo-module which can be downsized.SOLUTION: A superconduction cryo-module 1 according to the present disclosure includes: a superconduction acceleration hollow 12 having a cell unit 122 for accelerating an electron, a beam pipe unit 121A extending to an incidence side of the electron from the cell unit 122, and a discharge unit for discharging the electron accelerated by the cell unit 122; and an electronic gun 11 located in the beam pipe unit 121A of the superconduction acceleration hollow 12 and also on the same axis as a beam axis BA of the superconduction acceleration hollow 12, the electron gun discharging the electron to the cell unit 122.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a superconducting cryomodule.

Background Art

[0002] Superconducting accelerators enable 4K operation by forming a superconducting thin film on the inner cavity wall of a superconducting accelerating cavity, eliminating the need for a large-scale cryogenic cooling system. As a result, reductions in introduction cost, downsizing of the apparatus, and the like can be achieved. For example, Patent Document 1 discloses a superconducting accelerating radio-frequency cryomodule that employs a heat transfer cooling system in which the cooling stage of a Gifford-McMahon refrigerator and the superconducting accelerating cavity are connected by a heat transfer member for cooling.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the superconducting accelerating radio-frequency cryomodule described in Patent Document 1, the size of the superconducting accelerating radio-frequency cryomodule is large because the incident beam tube and the exit beam tube are provided outside the superconducting accelerating cavity. In view of the above problem, the present disclosure aims to provide a superconducting cryomodule capable of achieving downsizing.

Means for Solving the Problems

[0005] To solve the above-mentioned problems and achieve the objectives, the superconducting cryomodule according to the present disclosure comprises a superconducting accelerating cavity having a cell section for accelerating electrons, a beam pipe section extending from the cell section toward the electron inlet side, and an emission section for emitting electrons accelerated in the cell section, and an electron gun located inside the beam pipe section of the superconducting accelerating cavity and coaxial with the beam axis of the superconducting accelerating cavity, for emitting electrons to the cell section. [Effects of the Invention]

[0006] According to this disclosure, it is possible to provide a superconducting cryomodule that can be miniaturized. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is an overall view of the superconducting accelerating cavity of the superconducting cryomodule according to this disclosure. [Figure 2] Figure 2 is a cross-sectional view AA of the superconducting accelerating cavity of the superconducting cryomodule according to this disclosure, as shown in Figure 1. [Figure 3] Figure 3 is a schematic diagram showing an example of the configuration of the electron gun of the superconducting cryomodule according to this disclosure. [Modes for carrying out the invention]

[0008] Embodiments of this disclosure will be described in detail below with reference to the drawings. However, the embodiments described below will not limit this disclosure.

[0009] (First Embodiment) (Configuration of a superconducting cryomodule) Figure 1 is a schematic diagram showing an example configuration of a superconducting cryomodule according to the present disclosure. As shown in Figure 1, the superconducting cryomodule 1 comprises an electron gun 11, a superconducting accelerating cavity 12, a thermal shield 13, a magnetic shield 14, a vacuum chamber 15, an RF (Radio Frequency) input coupler 16, a vacuum valve 17, and a cooler 18.

[0010] The electron gun 11 is located inside the beam pipe section 121 of the superconducting accelerating cavity 12 and is coaxial with the beam axis BA of the superconducting accelerating cavity 12, and emits electrons into the cell section 122. In this embodiment, the beam axis BA is the central axis of the superconducting accelerating cavity 12. In the superconducting accelerating cavity 12, electrons move along the beam axis BA. In the superconducting cryomodule 1 according to the first embodiment, a thermionic emission electron gun is used for the electron gun 11. Thermionic emission electron gun emits electrons by heating the cathode, which releases free electrons from the metal forming the cathode, and then drawing out the emitted electrons by applying a potential to the anode. The configuration of the electron gun 11 will be described later.

[0011] The superconducting accelerating cavity 12 is a cavity formed from a superconducting material that accelerates electrons using an electric field formed by the application of high-frequency power. The superconducting accelerating cavity 12 is typically made from, for example, high-purity niobium. The energy of the electromagnetic field generated by the high-frequency power is consumed by the resistive heating of the metal constituting the cavity walls of the superconducting accelerating cavity 12. Therefore, by making the metal constituting the cavity walls of the superconducting accelerating cavity 12 superconducting, resistive heating can be suppressed, and energy loss from the electromagnetic field can be reduced. High-purity niobium is suitable as a material for the superconducting accelerating cavity 12 because it exhibits superconductivity at 9.2K.

[0012] The superconducting accelerating cavity 12 includes a cell section 122 for accelerating electrons, a beam pipe section 121A extending from the cell section 122 towards the electron inlet, and an emission section 121B for emitting electrons accelerated in the cell section 122. The beam pipe section 121A is connected to the cell section 122, and an electron gun 11 is positioned inside it coaxially with the beam axis BA. The beam pipe section 121A is tubular in shape and serves as the electron inlet for the cell section 122. The shape of the cell section 122 is determined to minimize the energy loss of high-frequency power in the cavity walls of the superconducting accelerating cavity 12. The cell section 122 may be formed in an elliptical shape, for example. The emission section 121B is connected to the cell section 122, and electrons accelerated in the cell section 122 flow into it and emit the incoming electrons to the outside. The emission section 121B may be formed in a tubular shape, for example.

[0013] The heat shield 13 blocks radiant heat emitted from a vacuum chamber 15 or the like, which is in a room temperature atmosphere, to the superconducting accelerating cavity 12. The heat shield 13 may be made of oxygen-free copper. Oxygen-free copper has a high thermal conductivity of 391 W / mK. Therefore, if oxygen-free copper is used for the heat shield 13, even if radiant heat is absorbed, the temperature of the heat shield 13 can be kept low by the cooler 18 connected to the heat shield 13.

[0014] The magnetic shield 14 is made of a magnetic field-absorbing material and absorbs the ambient magnetic field present outside the superconducting accelerating cavity 12. The magnetic shield 14 may be formed, for example, to cover the outside of the thermal shield 13. The magnetic shield 14 attracts the magnetic flux lines of magnetic fields that could become ambient magnetic fields, and plays a role in keeping unwanted magnetic fields away from the low-temperature area. In other words, the magnetic shield 14 shields the magnetic shield 14 from the inflow of magnetic fields such as the Earth's magnetic field from the outside of the magnetic shield 14 by forming a path for magnetic fields. The magnetic shield 14 is made using a metal with high magnetic permeability. For example, the magnetic shield 14 may be made using permalloy, which is a nickel-iron alloy containing 35 to 85% nickel.

[0015] The vacuum chamber 15 is a vacuum vessel whose interior is kept under vacuum. Inside the vacuum chamber 15, a superconducting accelerating cavity 12, a thermal shield 13, and a magnetic shield 14 are arranged in this order from the inside to the outside of the vacuum chamber 15. By keeping the inside of the vacuum chamber 15 under vacuum, it is possible to reduce radiant heat and conductive heat from the outside of the vacuum chamber 15 to these components inside the vacuum chamber 15.

[0016] The RF input coupler 16 is connected to an accelerating power supply source and supplies high-frequency power from the accelerating power supply source to the superconducting accelerating cavity 12. The RF input coupler 16 comprises a central part 161 connected to the outermost shell (outer wall part 117) of the electron gun 11 and an outer peripheral part 162 connected to the beam pipe part 121A. The RF input coupler 16 propagates high-frequency power from the accelerating power supply source to the superconducting accelerating cavity 12 by a coaxial structure formed by the beam pipe part 121A being the outer conductor and the outermost shell of the electron gun 11 being the inner conductor. The accelerating power supply source may be a high-frequency power supply source that realizes amplification of high-frequency power by vacuum tubes such as inductive output tubes (IOT) or klystrons. Alternatively, the accelerating power supply source may realize amplification of high-frequency power by semiconductor amplifiers such as FETs (Field Effect Transistors). Furthermore, the accelerating power supply source may be connected to an LLRF (Low Level Radio Frequency) control system to control the frequency of the high-frequency power. Furthermore, a circulator with a port connected to it may be provided between the accelerating power supply source and the RF input coupler 16 to prevent high-frequency power reflected from the superconducting accelerating cavity 12 from returning. In other words, the accelerating power supply equipment is composed of the RF input coupler 16, the accelerating power supply source, the LLRF control system, and the circulator.

[0017] The vacuum valve 17 is a valve that maintains a vacuum inside the superconducting accelerating cavity 12. A vacuum pump is connected to the vacuum valve 17, and after the air inside the superconducting accelerating cavity 12 is removed using the vacuum pump to create a vacuum, the valve of the vacuum valve 17 is closed to prevent air from entering from the outside, thereby maintaining the pressure inside the superconducting accelerating cavity 12 at a predetermined pressure.

[0018] The cooler 18 is connected to the superconducting accelerating cavity 12 to cool the superconducting accelerating cavity 12. A mechanical refrigerator such as a Gifford-McMahon refrigerator can be used as the cooler 18. In a Gifford-McMahon refrigerator, a refrigerant such as helium gas compressed by a compressor is sent into a cylinder, and cooling is achieved by repeatedly causing adiabatic expansion of the refrigerant gas through the reciprocating motion of a displacer inside the cylinder. In contrast, a liquefied helium refrigerator has a complex configuration including a helium liquefaction unit and requires extremely large equipment. A Gifford-McMahon refrigerator can be miniaturized by using a simple mechanical configuration such as a compressor and displacer.

[0019] Here, the connection between the cooler 18 and the superconducting accelerating cavity 12 will be explained using Figure 2. Figure 2 is an AA cross-sectional view of the superconducting accelerating cavity of the superconducting cryomodule according to the present disclosure. As shown in Figure 2, the cooler 18 comprises a first stage 181, a second stage 182, and a cold head 183. The first stage 181 refers to the stage of the cooler 18 with the lower temperature, and the second stage 182 refers to the stage of the cooler 18 with the higher temperature. The cold head 183 is the part that obtains cooling by the expansion of the refrigerant supplied from the compressor.

[0020] As shown in Figure 2, the first stage 181 is provided with a connection portion 19, and is connected to the superconducting acceleration cavity 12 via the connection portion 19. The connection portion 19 may be formed in a flange shape. As shown in Figure 2, the cooler 18 is arranged such that the angle formed by the central axis CA of the cooler 18 and the beam axis BA of the superconducting acceleration cavity 12 is a right angle, and the two axes are in a twisted positional relationship. That is, the central axis CA of the cooler 18 and the beam axis BA of the superconducting acceleration cavity 12 are arranged at positions that do not intersect. Accordingly, when the cylindrical radius of the vacuum chamber 15 is R, the radius of the superconducting acceleration cavity 12 is r, and the distance between the first stage 181 of the cooler 18 and the connection portion of the second stage 182 is d, the cylindrical radius R of the vacuum chamber 15 can satisfy the following formula (1). R<r+d...Formula (1) Therefore, the vacuum chamber 15 can be downsized.

[0021] (Configuration of Electron Gun) Next, the configuration of the electron gun 11 according to the present disclosure will be described with reference to Figure 3. Figure 3 is a diagram showing the first aspect of the electron gun of the superconducting cryomodule according to the present disclosure. As shown in Figure 3, the electron gun 11 includes a cathode 111, an anode 112, a heat shield plate portion 113, a notch portion 114, and a power source 115.

[0022] The cathode 111 is formed of a metal material, and emits free electrons when heated. The metal material is composed of a positive ion state with a stable closed shell of atoms and outer shell electrons (free electrons) that can move freely between atoms. As the temperature of the metal material increases, the energy of the free electrons rises, and the free electrons are emitted from the metal material across the potential barrier. The cathode 111 emits electrons using such a principle. Further, the tip portion of the cathode 111 is arranged at a position spaced upstream in the electron movement direction from the inlet portion of the cell portion 122. Thereby, electrons can be appropriately introduced from the electron gun 11 into the cell portion 122.

[0023] The anode 112 draws out electrons emitted from the cathode 111 using its electric potential and emits them outside the electron gun 11. A high-frequency electric field is created between the anode 112 and the heat shield plate 113 by the high-frequency power supplied from the RF input coupler 16, accelerating the electrons emitted from the cathode 111.

[0024] The heat shield portion 113 includes a plurality of metal plates formed around the cathode 111 that emits electrons. The plurality of metal plates in the heat shield portion 113 may be formed from at least two layers of metal plates. The number of metal plates constituting the heat shield portion 113 is not limited to two layers, but may be set to any number. The heat shield portion 113 is formed to cover, or surround, the cathode 111. For example, if the cathode 111 is cylindrical, the heat shield portion 113 will be formed in a cylindrical shape. In addition, a beam hole 113a through which electrons pass is formed at the tip of the heat shield portion 113. The heat shield portion 113 may be formed using a material that plays a role in shielding heat. For example, the heat shield portion 113 may be formed using oxygen-free copper.

[0025] The notch 114 is a portion of the outer wall 117 of the anode 112 that has been cut out. The notch 114 is positioned so that accelerating power can be supplied at the timing when electrons pass through the beam hole 112a of the anode 112. The shape of the notch 114 may be a hole or a cylindrical slit. This induces high-frequency power from the notch 114 into the electron gun 11. The induced high-frequency power propagates within the coaxial structure formed between the inner wall of the anode 112 and the outermost layer of the heat shield plate 113, generating a high-frequency accelerating electric field in the space 113b between the beam hole 112a of the anode 112 and the beam hole 113a of the heat shield plate 113. This introduces the first-stage accelerated electrons E into the cell 122.

[0026] The power supply 115 supplies potential to the multiple metal plates constituting the thermal shield plate section 113. The power supply 115 may be implemented, for example, by a DC (Direct Current) power supply. The power supply 115 applies a positive or negative voltage to the multiple metal plates relative to the potential of the cathode 111. This allows electrons emitted from the cathode 111 to be focused and extracted. In other words, the multiple metal plates constituting the thermal shield plate section 113 act as Wehnelt electrodes and extraction grids.

[0027] The dielectric 116 is provided between the anode 112 and the metal plate constituting the heat shield plate portion 113. The dielectric 116 may be made of, for example, a ceramic material, a glass material, or a plastic material. The dielectric 116 may be formed in a ring shape so as to cover the outer circumference of the metal plate. The dielectric 116 functions as an insulator with respect to direct current, but exhibits electrical conductivity with respect to high-frequency power supplied from a high-frequency power source. Furthermore, by providing the dielectric 116, the transmission time of high-frequency power reaching the beam hole 112a can be controlled.

[0028] The operation of the superconducting cryomodule 1 configured as described above will now be explained. By heating the cathode 111 of the electron gun 11, electrons E (see Figure 3) are emitted from the cathode 111. By applying a voltage between the cathode 111 and the metal plate when the power supply 115 is applied, the emitted electrons E are ejected from the electron gun 11. Because the heat shield plate 113 surrounds the cathode 111, the transfer of heat from the cathode 111 to the cell 122 is suppressed.

[0029] Electrons E emitted from the electron gun 11 travel along the beam axis BA through the beam pipe section 121A toward the cell section 122. Upon reaching the cell section 122, the electrons E are accelerated by the high-frequency power supplied from the RF input coupler 16 and emitted from the emission section 121B. A portion of the high-frequency power supplied from the RF input coupler 16 is drawn into the electron gun 11 through the notch 114. This accelerates the electrons E emitted from the cathode 111 and draws them out of the electron gun 11.

[0030] As described above, the superconducting cryomodule 1 according to the first embodiment comprises a superconducting accelerating cavity 12 having a cell section 122 for accelerating electrons, a beam pipe section 121A extending from the cell section 122 toward the electron incidence side, and an emission section 121B for emitting electrons accelerated in the cell section 122, and an electron gun 11 located inside the beam pipe section 121A of the superconducting accelerating cavity 12 and coaxial with the beam axis BA of the superconducting accelerating cavity 12, for emitting electrons to the cell section 122.

[0031] This configuration allows the electron gun of the superconducting cryomodule 1 to be housed inside the beam pipe section 121A of the superconducting accelerating cavity 12. Therefore, it becomes unnecessary to provide and connect the electron gun 11 outside the superconducting cryomodule 1, making it possible to miniaturize the entire device.

[0032] (Second Embodiment) Next, the superconducting cryomodule 1 according to the second embodiment will be described. The superconducting cryomodule 1 according to the second embodiment has the same configuration as the superconducting cryomodule 1 according to the first embodiment, except that the configuration of the electron gun 11 is different. Therefore, the configuration of the electron gun 11, which is different from that of the superconducting cryomodule 1 according to the first embodiment, will be described.

[0033] The electron gun 11 is a field emission electron gun, comprising an emitter, an extraction electrode, and an accelerating electrode. Electrons emitted from the emitter are extracted by an extraction voltage, and these electrons are accelerated by an accelerating voltage applied to the accelerating electrode. A field emission electron gun emits electrons by utilizing the field emission phenomenon that occurs when a high electric field is applied to a metal surface. Specifically, when a voltage of several kV is applied to an extraction electrode placed opposite the emitter, electrons are emitted from the emitter by the tunneling effect. Then, electrons that have passed through a hole formed in the center of the extraction electrode can be emitted with a predetermined energy by an accelerating voltage applied to the accelerating electrode.

[0034] This configuration allows the electron gun 11 to be placed inside the superconducting accelerating cavity 12, making it possible to miniaturize the superconducting cryomodule 1.

[0035] (Third embodiment) Next, the superconducting cryomodule 1 according to the third embodiment will be described. The superconducting cryomodule 1 according to the third embodiment has the same configuration as the superconducting cryomodule 1 according to the first embodiment, except for the configuration of the electron gun 11. Therefore, the configuration of the electron gun 11, which differs from that of the superconducting cryomodule 1 according to the first embodiment, will be described.

[0036] The electron gun 11 is a photoemission electron gun that emits electrons by irradiating a cathode with laser light and utilizing the photoelectric effect. The photoelectric effect is a phenomenon in which a substance absorbs photons and emits electrons. For example, when a metal is irradiated with short-wavelength laser light, electrons are emitted from the metal surface. The cathode of a photoemission electron gun can use a material with high quantum efficiency, which means the efficiency of the conversion of photons and electrons due to the photoelectric effect.

[0037] This configuration allows the electron gun 11 to be placed inside the superconducting accelerating cavity 12, making it possible to miniaturize the superconducting cryomodule 1.

[0038] (Structure and effect) A superconducting cryomodule according to a first aspect of this disclosure is a superconducting cryomodule 1 comprising a superconducting accelerating cavity 12 having a cell section 122 for accelerating electrons, a beam pipe section 121A extending from the cell section 122 toward the electron incidence side, and an emission section 121B for emitting electrons accelerated in the cell section 122, and an electron gun 11 located inside the beam pipe section 121A of the superconducting accelerating cavity 12 and coaxial with the beam axis BA of the superconducting accelerating cavity 12, for emitting electrons to the cell section 122.

[0039] This configuration allows the electron gun of the superconducting cryomodule 1 to be housed inside the beam pipe section 121A of the superconducting accelerating cavity 12. Therefore, it becomes unnecessary to provide and connect the electron gun 11 outside the superconducting cryomodule 1, making it possible to miniaturize the entire device.

[0040] A superconducting cryomodule according to a second aspect of the present disclosure is a superconducting cryomodule 1 according to a first aspect, wherein the electron gun 11 is a thermionic emission electron gun, and a beam hole through which electrons pass is formed around the cathode that emits electrons, and a heat shield plate portion 113 is provided which includes a plurality of metal plates formed surrounding the cathode.

[0041] This configuration prevents radiant heat from the cathode of the thermionic emission electron gun from being transferred to the superconducting accelerating cavity 12. As a result, the temperature of the superconducting accelerating cavity 12 can be maintained at a low temperature, which in turn allows the superconducting accelerating cavity 12 to remain in a superconducting state, enabling stable operation of the superconducting cryomodule 1.

[0042] A superconducting cryomodule 1 according to a third aspect of this disclosure further comprises an RF input coupler that supplies high-frequency power to a superconducting accelerating cavity 12, in a superconducting cryomodule according to the first or second aspect, wherein the RF input coupler 16 comprises a central portion 161 connected to the outermost shell of the electron gun 11 and an outer peripheral portion 162 connected to the beam pipe portion 121A, and propagates high-frequency power to the superconducting accelerating cavity 12 by a coaxial structure formed by the beam pipe portion 121A being the outer conductor and the outermost shell of the electron gun 11 being the inner conductor.

[0043] With this configuration, high-frequency power can be supplied from the RF input coupler 16 to a coaxial structure in which the beam pipe section 121A is the outer conductor and the outermost shell of the electron gun 11 is the inner conductor. Therefore, it becomes possible to accelerate the electrons emitted from the electron gun 11 with high-frequency power and introduce them into the cell section 122.

[0044] A superconducting cryomodule according to a fourth aspect of this disclosure is a superconducting cryomodule 1 according to a third aspect, wherein the electron gun 11 further comprises a notch 114 in which a portion of the anode is cut out, and high-frequency power is supplied through the notch 114 to apply an electric field to electrons emitted from the cathode of the electron gun 11, and the extraction and acceleration of electrons emitted from the cathode of the electron gun 11 are controlled by controlling the high-frequency power.

[0045] With this configuration, high-frequency power is supplied from the notch 114, making it possible to control the beam by applying an electric field to the electrons emitted from the cathode of the electron gun 11.

[0046] A superconducting cryomodule according to a fifth aspect of this disclosure is a superconducting cryomodule 1 according to any of the second to fourth aspects, wherein the electron gun 11 includes a dielectric 116 between the anode 112 and the metal plate constituting the heat shield plate portion 113.

[0047] This configuration allows the dielectric 116 to control the transmission time of high-frequency power. Therefore, electrons can be emitted from the electron gun 11 into the superconducting accelerating cavity 12 at an appropriate timing in accordance with the periodic fluctuations of the high-frequency power in the superconducting accelerating cavity 12.

[0048] A superconducting cryomodule according to a sixth aspect of this disclosure is a superconducting cryomodule 1 according to a first aspect, wherein the electron gun 11 is a field emission electron gun comprising an emitter, an extraction electrode, and an accelerating electrode, and extracts electrons emitted from the emitter with an extraction voltage and accelerates the electrons with an accelerating voltage from the accelerating electrode.

[0049] This configuration allows the electron gun 11 of the superconducting cryomodule 1 to be housed inside the beam pipe section 121 of the superconducting accelerating cavity 12. Therefore, it becomes unnecessary to provide and connect the electron gun 11 to the outside of the superconducting cryomodule 1, making it possible to miniaturize the entire device.

[0050] The superconducting cryomodule 1 according to the seventh aspect of this disclosure is a superconducting cryomodule 1 according to the first aspect, wherein the electron gun 11 is a photoemission electron gun that emits electrons by irradiating the cathode with laser light and utilizing the photoelectric effect.

[0051] This configuration allows the electron gun 11 of the superconducting cryomodule 1 to be housed inside the beam pipe section 121 of the superconducting accelerating cavity 12. Therefore, it becomes unnecessary to provide and connect the electron gun 11 to the outside of the superconducting cryomodule 1, making it possible to miniaturize the entire device.

[0052] The superconducting cryomodule according to the eighth aspect of this disclosure is the superconducting cryomodule 1 according to the first aspect, wherein the tip of the cathode of the electron gun 11 is positioned further upstream in the direction of electron movement than the entrance portion of the cell 122.

[0053] With this configuration, electrons emitted from the electron gun 11 can be introduced into the cell section 122, making it possible to appropriately accelerate the electrons emitted from the electron gun 11 in the cell section 122 to which high-frequency power is applied.

[0054] A superconducting cryomodule 1 according to a ninth aspect of this disclosure further comprises a cooler 18 connected to a superconducting accelerating cavity 12 and cooling the superconducting accelerating cavity 12, wherein the cooler 18 has a connecting portion 19 that connects to the superconducting accelerating cavity 12, and the cooler 18 is positioned at a right angle and twisted position between the central axis CA of the cooler 18 and the beam axis BA of the superconducting accelerating cavity 12.

[0055] This configuration makes it possible to reduce the height and width of the vacuum chamber 15 that houses the superconducting accelerating cavity 12, thereby enabling miniaturization of the superconducting cryomodule 1.

[0056] Although embodiments of the present invention have been described above, the embodiments are not limited to those described herein. Furthermore, the aforementioned components include those that can be easily conceived by those skilled in the art, those that are substantially the same, and those that fall within the so-called equivalent range. Moreover, the aforementioned components can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the components can be made without departing from the spirit of the embodiments described above. [Explanation of symbols]

[0057] 1. Superconducting cryomodule 11. Electron gun 111 Cathode 112 Anode 113 Heat shield part 114 Notch 115 Power supply 12 Superconducting Accelerating Cavities 13 Heat Shield 14 Magnetic Shielding 15 Vacuum chamber 16 RF Input Coupler 17 Vacuum valve 18 Cooler 181 Stage 1 182 Stage 2 183 Coldhead 19 Connection part BA beam axis CA center axis

Claims

1. A superconducting accelerating cavity having a cell section for accelerating electrons, a beam pipe section extending from the cell section toward the electron incidence side, and an emission section for emitting electrons accelerated in the cell section, The superconducting accelerating cavity comprises an electron gun located inside the beam pipe section and coaxial with the beam axis of the superconducting accelerating cavity, which emits electrons to the cell section. The electron gun comprises a heat shield plate section including a plurality of metal plates formed surrounding a cathode that emits electrons, through which a beam hole is formed for electrons to pass. Superconducting cryomodule.

2. The aforementioned electron gun is a thermionic emission electron gun. The superconducting cryomodule according to claim 1.

3. The system further comprises an RF input coupler that supplies high-frequency power to the superconducting accelerating cavity, The RF input coupler is The central part connected to the outermost shell of the electron gun, It comprises an outer periphery connected to the beam pipe section, The coaxial structure, formed by the beam pipe section acting as the outer conductor and the outermost shell of the electron gun acting as the inner conductor, propagates high-frequency power to the superconducting accelerating cavity. The superconducting cryomodule according to claim 1 or 2.

4. The electron gun further comprises a notch in which a portion of the anode is cut out, Through the aforementioned notch, high-frequency power is supplied to apply an electric field to the electrons emitted from the cathode of the electron gun. By controlling the aforementioned high-frequency power, the extraction and acceleration of electrons emitted from the cathode of the electron gun are controlled. The superconducting cryomodule according to claim 3.

5. The electron gun has a dielectric material between the anode and the metal plate constituting the heat shield plate. The superconducting cryomodule according to claim 2.

6. The electron gun has a dielectric material between the anode and the metal plate constituting the heat shield plate. The superconducting cryomodule according to claim 3.

7. The aforementioned electron gun is a field emission type electron gun, The system comprises an emitter, an extraction electrode, and an accelerating electrode, wherein electrons emitted from the emitter are extracted by an extraction voltage, and the electrons are accelerated by an accelerating voltage from the accelerating electrode. The superconducting cryomodule according to claim 1.

8. The aforementioned electron gun is a photo-emitting electron gun, By irradiating the cathode with laser light and utilizing the photoelectric effect, electrons are emitted. The superconducting cryomodule according to claim 1.

9. The electron gun is positioned such that the tip of the cathode is located further upstream in the direction of electron movement than the entrance portion of the cell. The superconducting cryomodule according to claim 1.

10. A superconducting accelerating cavity having a cell section for accelerating electrons, a beam pipe section extending from the cell section toward the electron incidence side, and an emission section for emitting electrons accelerated in the cell section, An electron gun is located inside the beam pipe portion of the superconducting accelerating cavity and is coaxial with the beam axis of the superconducting accelerating cavity, and emits electrons to the cell portion. The system comprises a cooler connected to the superconducting accelerating cavity for cooling the superconducting accelerating cavity, The cooling device has a connection part that connects to the superconducting accelerating cavity, The cooler is positioned such that the angle between the central axis of the cooler and the beam axis of the superconducting accelerating cavity is perpendicular and twisted. Superconducting cryomodule.

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