Superconducting electromagnet device and charged particle beam therapy device

Abstract

To provide a superconducting electromagnet device that is smaller than conventional devices while suppressing the effect of conductive heat from the vacuum vessel to the yoke. [Solution] The deflection electromagnet device comprises a pair of superconducting coil units provided in the vacuum space of a vacuum vessel, at least one yoke to which the coils included in the pair of superconducting coil units are fixed, and a plurality of support members supporting the yoke to which the coils are fixed. The pair of superconducting coil units are configured to generate an effective magnetic field region in a direction perpendicular to the direction of propagation of a charged particle beam (Z direction). At least one of the plurality of support members supports the yoke from a first direction. If the vertical direction is the Y direction and the direction perpendicular to the Y and Z directions is the X direction, the first direction is a direction having a predetermined angle with respect to the Y and Z directions.

Description

Technical Field

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[0001] The present invention relates to a superconducting magnet device and a charged particle beam therapy device.

Background Art

[0002] Conventionally, particle beam therapy has been performed in which a charged particle beam accelerated to high energy is irradiated onto a malignant tumor such as cancer to treat the malignant tumor. When a charged particle beam is irradiated onto an object, energy (dose) is imparted to the object along the path of the charged particle beam in the object. When concentrating the dose in a limited region (target) inside the object, in order for the charged particle beam to overlap the target, the charged particle beam is irradiated from various directions to enhance the concentration of the dose.

[0003] In order to irradiate a charged particle beam from various directions, a superconducting magnet device (deflection magnet device) may be used. Further, in Patent Document 1, a support mode of a coil in a vacuum vessel of a superconducting magnet device has been proposed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When using a superconducting magnet device to control the irradiation direction of a charged particle beam in particle beam therapy, miniaturization of the superconducting magnet device is desired from the viewpoint of constraints on installation space in a medical site. On the other hand, in a superconducting magnet device, when supporting a yoke to which a coil is fixed inside a vacuum vessel (cryostat), it is necessary to also consider the influence of conduction heat from the vacuum vessel to the yoke.

[0006] This invention provides a superconducting electromagnet device that is smaller than conventional devices while suppressing the effect of conductive heat from the vacuum vessel to the yoke. [Means for solving the problem]

[0007] The present invention includes the following embodiments. [Aspect 1] A deflection electromagnet device, A vacuum vessel that forms a vacuum space inside, A pair of superconducting coil units provided in the vacuum space, wherein each superconducting coil unit includes at least one coil, The pair of superconducting coil units includes at least one yoke to which the coils are fixed, The yoke on which the coil is fixed is supported by a plurality of support members relative to the vacuum vessel so as to avoid thermal contact with the vacuum vessel, Equipped with, A beam path through which a charged particle beam passes is formed between the pair of superconducting coil units. The pair of superconducting coil units are configured to generate an effective magnetic field region in a direction perpendicular to the direction of propagation of the charged particle beam (Z direction), At least one of the plurality of support members supports the yoke from a first direction, When the vertical direction is defined as the Y direction, and the direction perpendicular to the Y and Z directions is defined as the X direction, the first direction is a direction having a predetermined angle with respect to the Y and Z directions. Bending electromagnet device. [Aspect 2] A deflection electromagnet device according to Embodiment 1, The aforementioned plurality of support members are A first set including at least three support members that support the yoke from at least the +Z direction, A second set including at least three support members that support the yoke from at least the -Z direction, including, Bending electromagnet device. [Aspect 3] A deflection electromagnet device according to embodiment 2, The first set mentioned above is, The yoke is supported by at least two support members from the +Y direction and the +Z direction, The yoke is supported by at least one support member from the -Y direction and the +Z direction, Includes, The second set mentioned above is, The yoke is supported by at least two support members from the +Y direction and the -Z direction, The yoke is supported by at least one support member from the -Y direction and the -Z direction, including, Bending electromagnet device. [Aspect 4] A deflection electromagnet device according to Embodiment 3, At least two support members that support the yoke from at least the +Y direction and the +Z direction have an angle of 45 degrees or more and less than 90 degrees with respect to the Z axis when viewed from the -X direction. At least two support members that support the yoke from at least the -Y direction and the +Z direction have an angle with respect to the Z axis greater than -90 degrees and less than or equal to -45 degrees when viewed from the -X direction. At least two support members that support the yoke from at least the +Y direction and the -Z direction have an angle with respect to the Z axis greater than 90 degrees and 135 degrees or less when viewed from the -X direction. At least two support members that support the yoke from at least the -Y direction and the -Z direction have an angle with respect to the Z axis of -135 degrees or more and less than -90 degrees when viewed from the -X direction. Bending electromagnet device. [Aspect 5] A deflection electromagnet device according to any one of embodiments 2 to 4, The support members included in the first set and the support members included in the second set each support the yoke from directions including components in the X, Y, and Z directions. Bending electromagnet device. [Aspect 6] The deflection electromagnet device according to any one of Aspects 2 to 5, wherein the plurality of support members further includes a third set including at least two support members that support the yoke only from the Z direction, Deflection electromagnet device. [Aspect 7] The deflection electromagnet device according to any one of Aspects 2 to 6, wherein the plurality of support members further includes a fourth set including at least two support members that support the yoke only from the X direction, Deflection electromagnet device. [Aspect 8] The deflection electromagnet device according to Aspect 7, wherein when viewed from the Z direction, a virtual straight line passing through the support members included in the fourth set passes through the center of gravity of the yoke and the pair of superconducting coil units, Deflection electromagnet device. [Aspect 9] The deflection electromagnet device according to any one of Aspects 2 to 8, each support member of the first set is fixed to the +Z direction side surface of the yoke, each support member of the second set is fixed to the -Z direction side surface of the yoke, Deflection electromagnet device. [Aspect 10] The deflection electromagnet according to any one of Aspects from 3 to 9, at least three support members included in the first set include first and second support members fixed to the yoke at a first position in the Y direction and third and fourth support members fixed to the yoke at a second position in the Y direction, the X-direction interval between the first and second support members is larger than the X-direction interval between the third and fourth support members, the X-direction width of the yoke at the first position in the Y direction is larger than the X-direction width of the yoke at the second position in the Y direction, Deflection electromagnet device. [Aspect 11] The deflection electromagnet device according to any one of Aspects from 3 to 10, Each of the first set of yokes, each of the at least one support member supporting the yokes of the second set from at least the -Y and +Z directions, includes an elastic member between the vacuum vessel and at least one of the yokes that displaces in accordance with the thermal contraction of the yokes, Bending electromagnet device. [Aspect 12] A charged particle beam irradiation device equipped with the superconducting electromagnet device described in aspects 1 to 11. [Brief explanation of the drawing]

[0008] [Figure 1] Side cross-section illustrating the outline of a superconducting electromagnet device according to one embodiment. [Figure 2] Figure 2 is a schematic diagram (YZ cross-section) of the AA-line cross-section of the superconducting electromagnet apparatus shown in Figure 1. [Figure 3] Figure 3 is a schematic diagram (ZX cross-section) showing the BB line cross-section of the superconducting electromagnet apparatus in Figure 1. [Figure 4] Diagram showing the cooling structure and yoke support structure of a superconducting electromagnet device. [Figure 5] Diagram illustrating the support structure of the yoke in a superconducting electromagnet device. [Figure 6] Schematic diagram of a charged particle beam irradiation device equipped with a superconducting electromagnet. [Figure 7] Diagram illustrating the support structure of a modified superconducting electromagnet device. [Figure 8] Diagram illustrating the support structure of a modified superconducting electromagnet device. [Modes for carrying out the invention]

[0009] Embodiments of the present invention will be described below with reference to the drawings. In this specification, the term "direction" includes both "positive direction" and "negative direction," and has a different meaning from "orientation." Therefore, when simply "a predetermined direction" is used, the orientation is not limited. On the other hand, if it is described as "+X direction," the orientation is limited to positive, and if it is described as "-X direction," the orientation is limited to negative.

[0010] [Superconducting electromagnet device 1] <Overview> Figure 1 is a side cross-sectional view (XY cross-section) illustrating the outline of a superconducting electromagnet device 1 according to one embodiment. Figure 2 is a schematic diagram (YZ cross-section) showing the AA line cross-section of the superconducting electromagnet device 1 of Figure 1, and Figure 3 is a schematic diagram (ZX cross-section) showing the BB line cross-section of the superconducting electromagnet device 1 of Figure 1.

[0011] In this implementation, the superconducting electromagnet device 1 plays the role of a deflection electromagnet device that deflects the direction of propagation of the charged particle beam. As will be described in detail in [Charged Particle Beam Therapy Device], the superconducting electromagnet device 1 is used, for example, in the charged particle beam irradiation device 100 to irradiate the patient's isocenter with a charged particle beam from a predetermined direction. The superconducting electromagnet device 1 generally includes a vacuum vessel 10, a pair of superconducting electromagnet groups 20, a yoke 30, a shield 40, a suppression plate 50, a cooling device 60, and a support section 70.

[0012] Figure 1 is a schematic diagram of the superconducting electromagnet device 1. In Figure 1, the axis along the direction of propagation of the charged particle beam is the X-axis, the axis along the direction of the magnetic field generated by the superconducting electromagnet device 1 is the Z-axis, and the axis along the direction perpendicular to the X-axis and Z-axis is the Y-axis. The superconducting electromagnet device 1 is configured to focus the charged particle beam, which is incident from a wide range of deflection angles φ with respect to the X-axis in the XY plane, onto the isocenter O.

[0013] In Figure 1, the irradiation nozzle is omitted, and for the sake of simplicity, the isocenter O is set as the origin of the XYZ space, with the upstream side (accelerator side) being the positive direction of the X axis. The deflection angle φ is the angle relative to the X axis deflected at the deflection origin Q of the distribution electromagnet 123 in the XY plane.

[0014] The deflection angle φ is in the range of greater than -90 degrees and less than +90 degrees, and the positive (+Y-axis direction) deflection angle range and the negative (-Y-axis direction) deflection angle range may be different (asymmetrical). For example, the maximum positive deflection angle (φ=φMAX) may be one of 10 degrees, 15 degrees, 20 degrees, 25 degrees, 30 degrees, 35 degrees, 40 degrees, 45 degrees, 50 degrees, 60 degrees, 70 degrees, 80 degrees, and 85 degrees, and the maximum negative deflection angle (φ=-φMAX) may be one of -10 degrees, -15 degrees, -20 degrees, -25 degrees, -30 degrees, -35 degrees, -40 degrees, -45 degrees, -50 degrees, -60 degrees, -70 degrees, -80 degrees, and -85 degrees.

[0015] <Explanation of each element> (vacuum container 10) The vacuum vessel 10 (cryostat) forms a vacuum space 11 inside it. The inside of the vacuum vessel 10 is kept at an extremely low temperature by using a refrigerant or by using a cooling device 60, which will be described later. The effective magnetic field region may be kept as much of a vacuum as possible while maintaining the superconducting state of the superconducting electromagnet device 1 through which the charged particle beam passes. In this embodiment, a connection portion 12 that connects to a fan-shaped vacuum duct 124, which will be described later, is formed on the incident side of the charged particle beam of the vacuum vessel 10, and a window portion 13 made of Kapton (registered trademark) (polyimide film) is formed on the exit side of the charged particle beam.

[0016] (A pair of superconducting electromagnets 20) A pair of superconducting electromagnet groups 20 are provided in a vacuum space 11. The pair of superconducting electromagnet groups 20 includes a superconducting electromagnet group 20A and a superconducting electromagnet group 20B, with each superconducting electromagnet group containing at least one superconducting electromagnet. In this embodiment, superconducting electromagnet group 20A includes superconducting electromagnets 20A1 to 20A6, and superconducting electromagnet group 20B includes superconducting electromagnets 20B1 to 20B6. However, the number of superconducting electromagnets included in superconducting electromagnet groups 20A and 20B can be set as appropriate. For example, superconducting electromagnet groups 20A and 20B may each consist of a single superconducting electromagnet, or they may each consist of 2 to 5 or 7 or more superconducting electromagnets. The shapes of superconducting electromagnet groups 20A and 20B can also be set as appropriate.

[0017] The pair of superconducting electromagnets 20 are kept at an extremely low temperature via a heat transfer member cooled by a refrigerant, for example. Examples of refrigerants used to cool the heat transfer member include helium gas, liquid helium, or liquid nitrogen.

[0018] To elaborate further on the pair of superconducting electromagnet groups 20, superconducting electromagnet group 20A is composed of multiple superconducting electromagnets 20A1 to 20A6, and superconducting electromagnet group 20B is composed of multiple superconducting electromagnets 20B1 to 20B6. Three superconducting electromagnets are provided on the +Y side (upper side) of the straight line connecting the deflection source Q and the isocenter O by superconducting electromagnets 20A1 to 20A3 and superconducting electromagnets 20B1 to 20B3. In addition, three superconducting electromagnets are provided on the -Y side (lower side) of the straight line connecting the deflection source Q and the isocenter O by conduction electromagnets 20A4 to 20A6 and superconducting electromagnets 20B4 to 20B6. Thus, in this embodiment, the number of superconducting electromagnets provided on the upper and lower sides of the straight line connecting the deflection source Q and the isocenter O is three each, but is not limited to this. To reduce the stored energy, it is sufficient to have at least two superconducting electromagnets above and below the straight line connecting the deflection origin Q and the isocenter O.

[0019] In superconducting electromagnet groups 20A and 20B, superconducting electromagnets 20A1 and 20B1 are arranged adjacent to superconducting electromagnets 20A2 and 20B2, and superconducting electromagnets 20A2 and 20B2 are arranged adjacent to superconducting electromagnets 20A3 and 20B3. The superconducting coil pairs 20A1a to 20A3a and 20B1a to 20B3a of superconducting electromagnet groups 20A and 20B, respectively, which are arranged to straddle the path of the charged particle beam, are configured to generate effective magnetic field regions 131 to 133 in which the magnetic field is oriented in a direction perpendicular to the direction of propagation of the charged particle beam (X-axis) (Z-axis). Effective magnetic field region 131 is arranged adjacent to effective magnetic field region 132, and effective magnetic field region 132 is arranged adjacent to effective magnetic field region 133. If the Y-axis position of the isocenter O is set to Y=0, the absolute value of the Y-axis position of the effective magnetic field region 132 is larger than the absolute value of the Y-axis position of the effective magnetic field region 131, and the absolute value of the Y-axis position of the effective magnetic field region 133 is larger than the absolute value of the Y-axis position of the effective magnetic field region 132.

[0020] Similarly, in superconducting electromagnet groups 20A and 20B, superconducting electromagnets 20A4 and 20B4 are arranged adjacent to superconducting electromagnets 20A5 and 20B5, and superconducting electromagnets 20A5 and 20B5 are arranged adjacent to superconducting electromagnets 20A6 and 20B6. The superconducting coil pairs 20A4a to 20A6a and 20B4a to 20B6a of superconducting electromagnet groups 20A and 20B, respectively, which are arranged to straddle the path of the charged particle beam, are configured to generate effective magnetic field regions 141 to 143 in which the magnetic field is oriented in a direction (Z axis) perpendicular to the direction of propagation of the charged particle beam (X axis). Effective magnetic field region 141 is arranged adjacent to effective magnetic field region 142, and effective magnetic field region 142 is arranged adjacent to effective magnetic field region 143. If the Y-axis position of isocenter O is set to Y=0, the absolute value of the Y-axis position of the effective magnetic field region 142 is larger than the absolute value of the Y-axis position of the effective magnetic field region 141, and the absolute value of the Y-axis position of the effective magnetic field region 143 is larger than the absolute value of the Y-axis position of the effective magnetic field region 142.

[0021] In other words, the superconducting electromagnet groups 20A and 20B each generate multiple uniform magnetic fields (effective magnetic field regions 131-133 and 141-143) oriented perpendicular to the direction of propagation of the charged particle beam and the direction of the beam's deflection angle φ (the Z-axis direction in the figure). The shape of the effective magnetic field regions and the magnetic flux density can be adjusted by adjusting the shape of the superconducting coils and magnetic poles, and by adjusting the flowing current.

[0022] Furthermore, the gap (distance in the Z-axis direction) between opposing superconducting coils through which the charged particle beam passes is sufficiently small compared to the spread range of the charged particle beam in the XY plane; therefore, the spread of the charged particle beam in the Z-axis direction is not considered. Also, although a noticeable gap exists between adjacent effective magnetic field regions in the diagram for illustrative purposes, the effect of this gap can be considered negligibly small.

[0023] Figure 2 is a cross-sectional view of the superconducting electromagnet device 1 shown in Figure 1, along line AA. As described above, the superconducting electromagnet device 1 comprises two sets of superconducting electromagnet groups 20A and 20B. Each of the superconducting electromagnet groups 20A and 20B consists of multiple superconducting electromagnets 20A1 to 20A3, 20A4 to 20A6, 20AB to 20B3, and 20B4 to 20B6, respectively.

[0024] The superconducting electromagnet 20A1 is equipped with opposing pairs of superconducting coils 20A1a, and a magnetic pole 20A1b is incorporated inside the superconducting coil pair 20A1a. Similarly, the other superconducting electromagnets 20A2-20A3 and 20A4-20A6 are equipped with opposing pairs of superconducting coils 20A2a-20A3a and 20A4a-20A6a, respectively, and a magnetic pole 20A2b-20A3b and 20A4b-20A6b are incorporated inside them. Similarly, the superconducting electromagnet 20B1 is equipped with opposing pairs of superconducting coils 20B1a, with magnetic poles 20B1b incorporated inside the superconducting coil pair 20B1a. Likewise, the other superconducting electromagnets 20B2-20B3 and 20B4-20B6 are equipped with opposing pairs of superconducting coils 20B2a-20B3a and 20B4a-20B6a, respectively, with magnetic poles 20B2b-20B3b and 20B4b-20B6b incorporated inside them.

[0025] The magnetic poles 20A1b-20A6b and 20B1b-20B6b are used to increase the magnetic field strength between the superconducting electromagnets 20A1-20A6 and 20B1-20B6, respectively, but the configuration may also be implemented without magnetic poles. Furthermore, magnetic poles do not need to be used for all of the superconducting coil pairs 20A1a-20A6a and 20B1a-20B6a; they may be used only for the desired superconducting coils as needed. For example, the presence or absence of magnetic poles may be changed depending on the required radius of curvature for the circular motion of the charged particle beam in the effective magnetic field region.

[0026] A power supply (not shown) is connected to the superconducting electromagnet device 1, and current (excitation current) is supplied from the power supply to the superconducting electromagnets 20A1~20A3, 20A4~20A6, 20AB~20B3, and 20B4~20B6, thereby forming effective magnetic field regions 131~133 and 141~143.

[0027] In other words, the pair of superconducting electromagnets 20 can generate a magnetic field (effective magnetic field region) oriented perpendicular to the direction of propagation of the charged particle beam and the direction of the beam's deflection angle φ (the Z direction in the figure). The shape of the effective magnetic field region and the magnetic flux density can be adjusted by adjusting the shape of the superconducting coils and magnetic poles, and by adjusting the flowing current.

[0028] Each coil in the pair of superconducting electromagnets 20 generates multiple uniform magnetic fields (effective magnetic field regions) oriented perpendicular to the direction of propagation of the charged particle beam before deflection and the direction of the beam's deflection angle φ (the Z-axis direction in the figure). The shape of the effective magnetic field region and the magnetic flux density can be adjusted by adjusting the shape of the coils and magnetic poles and the flowing current.

[0029] Although an example was shown where the number of superconducting electromagnets in superconducting electromagnets 20A1 to 20A3 is the same as the number of superconducting electromagnets in superconducting electromagnets 20A4 to 20A6, the number of superconducting electromagnets may be different in the upper and lower halves of the superconducting electromagnet group 20A. For example, the number of superconducting electromagnets in the upper half (positive (+Y axis direction) side) of the superconducting electromagnet group 20A may be set to 3 to form effective magnetic field regions 131-133, and the number of superconducting electromagnets in the lower half (negative (-Y axis direction) side) of the superconducting electromagnet group 20A may be set to 2 to form effective magnetic field regions 141-142. Furthermore, if the range of the deflection angle φ in the positive (+Y axis direction) and the range of the deflection angle φ in the negative (-Y axis direction) are asymmetrical, the effective magnetic field regions should be formed asymmetrically accordingly. This reduces the unused effective magnetic field regions, thereby lowering manufacturing costs and power consumption.

[0030] (Regarding the deflection of charged particle beams) A charged particle beam incident within a positive deflection angle range (φ=greater than 0 to φMAX) will be incident into one of the effective magnetic field regions 131 to 133, depending on the deflection angle φ. Regardless of which of the effective magnetic field regions 131 to 133 the charged particle beam is incident into, the shape and magnetic flux density B of the effective magnetic field regions 131 to 133 are set so that the charged particle beam is deflected and converges to the isocenter O. Similarly, for the effective magnetic field regions 141 to 143, a charged particle beam incident within a negative deflection angle range (φ=less than 0 to -φMAX) will be incident into one of the effective magnetic field regions 141 to 143, depending on the deflection angle φ. Regardless of which of the effective magnetic field regions 141 to 143 the charged particle beam is incident into, the shape and magnetic flux density B of the effective magnetic field regions 141 to 143 are set so that the charged particle beam is deflected and converges to the isocenter O. The magnetic field directions in effective magnetic field regions 131-133 and 141-143 are opposite to each other.

[0031] The deflection angle φ of the charged particle beam incident on the superconducting electromagnet device 1 is controlled by the distribution electromagnet 123. The distribution electromagnet 123 comprises an electromagnet that generates a magnetic field perpendicular to the direction of propagation of the charged particle beam supplied from the accelerator (not shown) (X-axis in the figure) (Z-axis in the figure), and a control unit (not shown) that controls the strength and direction of the magnetic field to deflect the passing charged particle beam. The distribution electromagnet 123 deflects the charged particle beam in the XY plane by controlling the strength and direction (Z-axis direction) of the magnetic field of the distribution electromagnet 123 with the electromagnet control unit (not shown), which will be described later, and emits the charged particle beam deflected at a deflection angle φ at the deflection starting point Q to the superconducting electromagnet device 1. Here, the deflection starting point Q and the isocenter O are on the X-axis.

[0032] The range of the deflection angle φ of the charged particle beam, which is deflected by the distribution electromagnet 123 and incident on the effective magnetic field regions 131-133 and 141-143 of the superconducting electromagnet device 1, is from the maximum positive deflection angle (φ=φMAX) to the maximum negative deflection angle (φ=-φMAX). The maximum positive deflection angle φMAX is an angle of 10 degrees or more and less than 90 degrees, and the maximum negative deflection angle -φMAX is an angle greater than -90 degrees and less than or equal to -10 degrees. The deflection angle φ and the irradiation angle θ, described later, are the angles of the path of the charged particle beam relative to the X axis in the XY plane.

[0033] (York 30) The yoke 30 fixes the superconducting electromagnets included in the pair of superconducting electromagnet groups 20. The yoke 30 includes a fixing portion 31A to which the superconducting electromagnets 20A1 to 20A6 included in the superconducting electromagnet group 20A are fixed, and a fixing portion 31B to which the superconducting electromagnets 20B1 to 20B6 included in the superconducting electromagnet group 20B are fixed. That is, in this embodiment, all the coils included in the pair of superconducting electromagnet groups 20 are fixed to a single yoke 30. However, multiple yokes may be provided, and at least two coils included in the pair of superconducting electromagnet groups 20 may be fixed to one or more of these yokes. Furthermore, by fixing at least two coils to one yoke, the relative positions of the coils can be fixed. Therefore, the coils can be more easily arranged in an appropriate relative positional relationship. The yoke 30 is cooled directly, for example, via a heat transfer member cooled by a refrigerant. Alternatively, the pair of superconducting electromagnet groups 20, cooled via a heat transfer member, may be fixed to the yoke 30 in a heat-transferable manner, thereby being cooled to an extremely low temperature. Examples of refrigerants used to cool the heat transfer components include helium gas, liquid helium, or liquid nitrogen. Furthermore, the yoke 30 is fixed to the vacuum container 10 by horizontal protrusions. The number of horizontal protrusions is not limited, but two may be provided at each location facing the inner surface of the vacuum container 10.

[0034] Furthermore, in this embodiment, a beam path BP through which the charged particle beam passes is formed between the superconducting electromagnet group 20A and the superconducting electromagnet group 20B of the pair of superconducting electromagnet groups 20. The beam path BP can be formed with an extent on the YZ plane depending on the angle of incidence of the charged particle beam to the superconducting electromagnet device 1, the incidence position, and the magnetic field generated by the pair of superconducting electromagnet groups 20.

[0035] In this embodiment, the beam path BP and the pair of superconducting electromagnets 20 are spatially connected. That is, the beam path BP and the pair of superconducting electromagnets 20 are provided in the vacuum space 11 and are not spatially isolated. This allows the superconducting electromagnets 20A and 20B to be spaced closer together compared to the case where the beam path BP and the pair of superconducting electromagnets 20 are spatially isolated, thereby enabling miniaturization of the superconducting electromagnet device 1. Furthermore, by bringing the superconducting electromagnets closer together, the magnetic field generated when the same current is passed through them can be made stronger.

[0036] In cases where the beam path BP and the pair of superconducting electromagnet groups 20 are not spatially connected, for example, the superconducting electromagnet group 20A and the superconducting electromagnet group 20B are housed in separate vacuum vessels (cryostats), and the beam path BP is formed between these vacuum vessels. Alternatively, for example, the superconducting electromagnet group 20A and the superconducting electromagnet group 20B are housed in the same vacuum vessel, but a vacuum duct is provided between them, and this vacuum duct defines the beam path BP. In this embodiment, the distance between the superconducting electromagnet group 20A and the superconducting electromagnet group 20B can be brought closer compared to these cases.

[0037] (Shield 40) The shield 40 is provided in the vacuum space 11 to prevent radiant heat from flowing into the pair of superconducting electromagnets 20 and the yoke 30. The shield 40 is made of, for example, an aluminum plate and is provided so as to surround the yoke 30. This can contribute to keeping the pair of superconducting electromagnets 20 at a very low temperature (for example, about 4K) by minimizing the inflow of radiant heat into the pair of superconducting electromagnets 20. In this embodiment, the shield 40 is cooled to about 50K by a cooling device 60 described later, so that the vacuum space 11 of the vacuum vessel 10 is cooled in stages towards the center (multilayer cooling structure). The shield 40 includes an opening 41 and a transparent portion 42.

[0038] The aperture 41 is formed in the shield 40 to allow the charged particle beam to pass through. The aperture 41 is formed on the upstream side of the shield 40 in the direction of travel of the charged particle beam. The charged particle beam, having traveled towards the shield 40, passes through the aperture 41 and enters the inside of the shield 40 without penetrating the shield 40. By passing the charged particle beam through the aperture 41, beam scattering can be suppressed when the beam enters the shield 40.

[0039] The permeable section 42 is formed to allow the charged particle beam to pass through. The permeable section 42 is formed on the downstream side of the shield 40 in the direction of travel of the charged particle beam. The charged particle beam that has passed through the shield 40 passes through the permeable section 42 and exits to the outside of the shield 40. By covering the exit side of the beam path BP with the permeable section 42, the inflow of radiant heat into the shield 40 can be suppressed.

[0040] In this embodiment, the boundary between the vacuum space 11 of the vacuum vessel 10 and the atmospheric environment is a window portion 13 formed of Kapton® (polyimide film). Therefore, radiant heat is more likely to flow into the exit side of the shield 40 compared to the inlet side. Thus, by making the inlet side of the shield 40 an opening 41 and the exit side from the shield 40 a transparent portion 42, it becomes easier to achieve both suppression of beam scattering and prevention of radiant heat inflow.

[0041] (Suppression plate 50) The suppression plate 50 is a plate that suppresses the inflow of radiant heat from the shield 40 through the opening 41 into the pair of superconducting electromagnets 20 and the yoke 30 inside the shield 40. The material of the suppression plate 50 is, for example, aluminum. In this embodiment, the vacuum vessel 10 and the fan-shaped vacuum duct 124 connected to the vacuum vessel 10 are installed in contact with the ambient temperature (approximately 300K) atmosphere. The shield 40 suppresses the inflow of radiant heat from these ambient temperature (approximately 300K) regions into the yoke 30, etc., which has been cooled to approximately 4K, but the suppression plate 50 suppresses the inflow of radiant heat in areas that cannot be covered by the shield 40. The suppression plate 50 is installed so as to be in contact with the shield 40 and is therefore cooled to the same temperature (approximately 50K) as the shield 40 by the cooling device 60.

[0042] Furthermore, the suppression plate 50 can be positioned such that radiant heat from the vacuum vessel 10, which is in contact with room temperature, does not reach the pair of superconducting electromagnets 20. As an example, in this embodiment, the suppression plate 50 is positioned so that it penetrates into the interior of the yoke 30 in the X direction when viewed from the Y direction. In other words, the suppression plate 50 and the yoke 30 are positioned so that they overlap in the X direction. This makes it possible to suppress the effects of radiant heat more effectively. For example, the radiant heat RH shown in Figure 3 could reach the yoke 30 if the suppression plate 50 were not provided, but this is suppressed by the presence of the suppression plate 50.

[0043] (Cooling device 60) Figure 4 shows the cooling structure of the superconducting electromagnet device 1 and the support structure of the yoke 30. The cooling device 60 cools the components inside the vacuum space 11. In this embodiment, the cooling device 60 is a so-called multilayer cooling structure, cooling the shield 40 and the suppression plate 50 to about 50K, and cooling the pair of superconducting electromagnet groups 20 and the yoke 30 to about 4K. By gradually lowering the temperature toward the interior of the vacuum space 11, the ultra-low temperature environment inside can be maintained more efficiently and stably. The number of cooling stages and the temperature in Kelvin at each stage can be set as appropriate.

[0044] The specific configuration of the cooling device 60 can be designed as appropriate. In this embodiment, a multi-stage refrigerator capable of cooling to approximately 4K and approximately 50K is used as the cooling device 60. The cooling device 60 includes a refrigerator 61 and cold heads 62 and 63. The refrigerator 61 cools the cooling medium. The cold head 62 receives cooling from the cooling medium cooled by the refrigerator 61 and cools the object to be cooled in the vacuum container 10. In this embodiment, the cold head 62 cools the shield 40 to approximately 50K, and the cold head 63 cools the yoke 30 to approximately 4K.

[0045] In this embodiment, since a single yoke 30 fixes all the coils included in a pair of superconducting electromagnet groups 20, there is no need to provide a cooling device 60 for each yoke, and the coils can be cooled with a relatively small number of cooling devices 60, thus enabling efficient cooling.

[0046] (Support Section 70) Refer to Figure 5 for both Figure 4 and Figure 5. Figure 5 is an explanatory diagram of the support structure of the yoke 30 of the superconducting electromagnet device 1. The support section 70 supports the yoke 30 to which the superconducting electromagnets 20A1~20A6 and 20B1~20B6, which are included in the pair of superconducting electromagnet groups 20, are fixed. The support section 70 includes support members 71a~71h. The support members 71a~71h support the yoke 30 to which the superconducting electromagnets 20A1~20A6 and 20B1~20B6 are fixed, so as to avoid thermal contact with the vacuum vessel 10.

[0047] In Figures 4-5 and Figures 7-8 relating to the modified examples described later, when the reference numerals for support members are listed in parallel, the support member identified by the first reference numeral is positioned towards the front of the page, and the support member identified by the second reference numeral is positioned towards the back of the page. For example, in Figure 4, where the reference numerals 71b and 71a are listed together, support member 71b is positioned towards the front of the page, and support member 71a is positioned towards the back of the page, with the two overlapping when viewed from the front of the page.

[0048] In this embodiment, a heat insulating member 73 is interposed between the multiple support members 71a to 71h and the fixing portion 14 on the vacuum container 10 side to which the multiple support members 71a to 71h are fixed. As a result, the multiple support members 71a to 71h can support the yoke 30 while avoiding thermal contact with the vacuum container 10.

[0049] Furthermore, the multiple support members 71a to 71h are connected to the shield 40 via thermal anchors 64. Therefore, the multiple support members 71a to 71h are maintained at approximately 50K. In other words, although the multiple support members 71a to 71h connect the vacuum vessel 10 (approximately 300K) and the yoke 30 (approximately 4K), the thermal anchors 64 maintain the temperature at approximately 50K, thereby suppressing the influence of heat transfer from the vacuum vessel 10 to the yoke 30.

[0050] The multiple support members 71a to 71h are rod-shaped members and are formed, for example, from a titanium alloy material with low thermal conductivity. In this embodiment, 71a to 71h support the yoke 30 so that it is suspended in mid-air. For example, each of the support members 71a to 71h supports the yoke 30 from a predetermined direction. The predetermined direction includes components of the X, Y, and Z directions, respectively.

[0051] In this embodiment, for example, the support member 71a is configured to support the yoke 30 from a direction having a predetermined angle with respect to the Y and Z directions. That is, the support member 71a can be made longer than when the yoke 30 is supported from the vertical direction (Y direction) or the width direction (Z direction) of the vacuum vessel 10. In order to suppress the effect of conductive heat from the vacuum vessel 10 (approximately 300K) to the yoke 30 (approximately 4K), it is necessary to ensure a certain length of the support member connecting the two. When the support member supports the yoke 30 from the vertical direction (Y direction) or the width direction (Z direction) of the vacuum vessel 10, it is necessary to ensure a certain distance between the yoke 30 and the inside of the vacuum vessel 10 in order to ensure the length of the support member. This may lead to an increase in the size of the vacuum vessel 10. In this embodiment, by supporting the yoke 30 from a direction having a predetermined angle with respect to the Y and Z directions, it is possible to achieve miniaturization of the vacuum vessel 10 while ensuring the length of the support member.

[0052] In this embodiment, all of the support members 71a to 71h support the yoke 30 from directions that have a predetermined angle with respect to the Y and Z directions.

[0053] Furthermore, in this embodiment, support members 71a to 71d constitute a set S1 of support members that supports the yoke 30 from at least the +Z direction. Support members 71e to 71h constitute a set S2 of support members that supports the yoke 30 from at least the -Z direction. This allows for a longer support member length compared to the case where the yoke 30 is simply supported from the vertical direction (Y direction). In addition, sets S1 and S2 may each include at least three support members. This allows for stable support of the yoke 30.

[0054] Furthermore, in this embodiment, set S1 includes support members 71a and 71b that support the yoke 30 from at least the +Y direction and the +Z direction, and support members 71c and 71d that support the yoke 30 from at least the -Y direction and the +Z direction. The support members 71a and 71b, when viewed from the front of the paper in Figure 4, preferably have an angle with the Z axis greater than 0 degrees and less than 90 degrees, and more preferably 45 degrees or more and less than 90 degrees. This configuration allows for miniaturization of the device while supporting the yoke 30 with appropriate strength. The support members 71c and 71d, when viewed from the front of the paper in Figure 4, preferably have an angle with the Z axis greater than -90 degrees and less than 0 degrees, and more preferably greater than -90 degrees and -45 degrees or less. This configuration allows for miniaturization of the device while supporting the yoke 30 with appropriate strength. Furthermore, set S2 is provided so as to be symmetrical with respect to set S1 with respect to the XY plane. Set S2 includes support members 71e and 71f that support the yoke 30 from at least the +Y direction and the -Z direction, and support members 71g and 71h that support the yoke 30 from at least the -Y direction and the -Z direction. The support members 71e and 71f preferably have an angle with the Z axis greater than 90 degrees and less than 180 degrees when viewed from the plane of the paper in Figure 4, and more preferably between 135 degrees and less than 180 degrees. With this configuration, the yoke 30 can be supported with appropriate strength while the device is miniaturized. Furthermore, it is preferable that the support members 71g and 71h have an angle with the Z-axis greater than -180 degrees and less than -90 degrees when viewed from the plane of the paper in Figure 4, and more preferably greater than -180 degrees and less than or equal to -135 degrees. By configuring it in this way, the yoke 30 can be supported with appropriate strength while the device is miniaturized. Since the support members included in sets S1 and S2 support the yoke 30 from at least the Y direction and the Z direction, the load on the yoke 30 can be supported while ensuring the length of the support members.

[0055] Furthermore, in this embodiment, the support members 71a to 71h included in sets S1 and S2 support the yoke 30 from directions including components in the X, Y, and Z directions, respectively. This makes it possible to further suppress the enlargement of the vacuum vessel 10 while ensuring the lengths of the multiple support members 71a to 71h. In addition, it can support not only the load on the yoke 30 but also the thermal contraction force during cooling and rotation due to electromagnetic force.

[0056] Furthermore, in this embodiment, each support member of set S1 is fixed to the side surface of the yoke 30 in the +Z direction, and each support member of set S2 is fixed to the side surface of the yoke 30 in the -Z direction. This makes it possible to secure the length of the support members compared to the case where the support members that support the load of the yoke 30 are fixed to the top or bottom surface of the yoke 30.

[0057] Furthermore, in this embodiment, an elastic member 72 is provided between each of the support members 71c, 71d of set S1 and the support members 71e, 71f of set S2 and the vacuum container 10, which displaces in accordance with the thermal contraction of the yoke 30. The elastic member 72 is, for example, a disc spring. The yoke 30 and the multiple rod-shaped support members 71a to 71h undergo thermal contraction when cooled from room temperature to a low temperature (approximately 4K). By providing the elastic member, the yoke 30 can be properly supported by the multiple support members 71a to 71h even if thermal contraction occurs. In this embodiment, the elastic member 72 is provided between the support members 71c, 71d, 71e, 71f and the vacuum container 10, but the elastic member 72 may also be provided between the support members 71c, 71d, 71e, 71f and the yoke 30. Even with such a configuration, the yoke 30 can be properly supported by the multiple support members 71a to 71h even if thermal contraction occurs. In other words, an elastic member 72 that displaces in accordance with the thermal contraction of the yoke 30 may be included between each of the support members 71c and 71d of set S1 and the support members 71e and 71f of set S2 and at least one of the vacuum container 10 and the yoke 30.

[0058] [Charged particle beam therapy device] Figure 6 is a schematic diagram of a charged particle beam irradiation device 100 equipped with a superconducting electromagnet device 1. The charged particle beam irradiation device 100 includes the superconducting electromagnet device 1. The charged particle beam irradiation device 100 may further include an accelerator 110 and a beam transport system 120.

[0059] The accelerator 110 is a device that generates a charged particle beam, and is, for example, a synchrotron, a cyclotron, or a linear accelerator. The charged particle beam generated in the accelerator 110 is guided to the superconducting electromagnet device 1 through the beam transport system 120.

[0060] The beam transport system 120 includes one or more charged particle beam adjusting means 121, a vacuum duct 122, a distribution electromagnet 123, and a fan-shaped vacuum duct 124. The accelerator 110, the charged particle beam adjusting means 121, and the distribution electromagnet 123 are connected by the vacuum duct 122, and the distribution electromagnet 123 and the superconducting electromagnet device 1 are connected by the fan-shaped vacuum duct 124. By making the shape of the fan-shaped vacuum duct 124 in the XY plane (see Figure 1) fan-shaped, even a charged particle beam deflected with a deflection angle φ of 10 degrees or more can pass through the vacuum duct, and it can be made smaller compared to a rectangular vacuum duct, reducing the installation space.

[0061] The charged particle beam is generated in the upstream accelerator 110, travels through the vacuum duct 122 and the fan-shaped vacuum duct 124 to avoid or reduce attenuation, and is guided to the downstream superconducting electromagnet device 1 while being adjusted by the charged particle beam adjustment means 121.

[0062] The charged particle beam adjustment means 121 may include, as appropriate according to the specifications, a beam slit for adjusting the beam shape and / or dose of the charged particle beam, an electromagnet for adjusting the direction of travel of the charged particle beam, a quadrupole electromagnet for adjusting the beam shape of the charged particle beam, and a steering electromagnet for fine-tuning the beam position of the charged particle beam.

[0063] The path of the charged particle beam from the distribution electromagnet 123 to the isocenter O (the affected area of ​​the patient) differs depending on the irradiation angle θ. As a result, the optical elements that the charged particle beam encounters also change depending on the irradiation angle θ, and the beam shape of the charged particle beam at the isocenter O may change depending on the irradiation angle θ. To address this, for example, a charged particle beam adjustment means 121 provided upstream of the superconducting electromagnet device 1 may be controlled for each irradiation angle θ to adjust the beam shape of the charged particle beam at the isocenter O to be appropriate.

[0064] The distribution electromagnet 123 is configured to continuously deflect the charged particle beam at a deflection angle φ and emit the charged particle beam to the superconducting electromagnet device 1. The superconducting electromagnet device 1 is configured to continuously change the irradiation angle θ of the incident charged particle beam directed toward the isocenter O according to the deflection angle φ. [Differentiation]

[0065] Figure 7 is an explanatory diagram of the support structure of a modified superconducting electromagnet device 901. This modified example differs from the vacuum vessel 10 and yoke 30 of the above embodiment in that the vacuum vessel and yoke are divided into upper and lower sections. The following description will focus on the differences from the above embodiment, and parts that may have the same configuration as the above embodiment will be omitted from illustration or description as appropriate. For example, in the following, the illustration and description of the configurations corresponding to the shield 40, suppression plate 50, and cooling device 60 of the above embodiment are omitted, but the modified example may also have the same configuration as the shield 40, suppression plate 50, and cooling device 60.

[0066] In this modified example, the superconducting electromagnet device 901 includes an upper vacuum vessel 910A and a lower vacuum vessel 910B. A yoke 930A is housed in vacuum vessel 910A, and a yoke 930B is housed in vacuum vessel 910B. The interiors of yokes 930A and 930B can be configured similarly to the interior of yoke 30 in the above embodiment. For example, superconducting electromagnets 20A1 to 20A3 and 20B1 to 20B3 are fixed to yoke 930A, and superconducting electromagnets 20A4 to 20A6 and 20B4 to 20B6 are fixed to yoke 930B.

[0067] The superconducting electromagnet device 901 includes a support section 970 that supports the yokes 930A and 930B. The support section 970 includes support members 71a1 to 71h1 that support the yoke 930A and support members 71a2 to 71h2 that support the yoke 930B. Figure 8 is an explanatory diagram of the support structure of a modified superconducting electromagnet device, illustrating the arrangement of the support members 71a1 to 71h1 and the support members 71a2 to 71h2 that support the yoke 930B.

[0068] Support members 71a1 to 71d1 constitute a set of support members corresponding to set S1 of the above embodiment, and support the yoke 930A from the +Z direction even without the yoke 930A. The angle that support members 71a1 and 71b1 make with the Z-axis, viewed from the front of the paper in Figure 8, is preferably greater than 0 degrees and less than 90 degrees, and more preferably between 45 degrees and less than 90 degrees. This configuration allows for miniaturization of the device while supporting the yoke 930 with appropriate strength. Furthermore, the angle that support members 71c1 and 71d1 make with the Z-axis, viewed from the front of the paper in Figure 8, is preferably greater than -90 degrees and less than 0 degrees, and more preferably greater than -90 degrees and less than or equal to -45 degrees. This configuration allows for miniaturization of the device while supporting the yoke 930A with appropriate strength.

[0069] Support members 71e1 to 71h1 constitute a set of support members corresponding to set S2 of the above embodiment, and support the yoke 930A from the -Z direction even without the yoke 930A. The angle that support members 71e1 and 71f1 make with the Z-axis, viewed from the plane of the paper in Figure 8, is preferably greater than 90 degrees and less than 180 degrees, and more preferably between 135 degrees and less than 180 degrees. This configuration allows for miniaturization of the device while supporting the yoke 930A with appropriate strength. Furthermore, the angle that support members 71g1 and 71h1 make with the Z-axis, viewed from the plane of the paper in Figure 4, is preferably greater than -180 degrees and less than -90 degrees, and more preferably greater than -180 degrees and less than or equal to -135 degrees. This configuration allows for miniaturization of the device while supporting the yoke 930A with appropriate strength.

[0070] Support members 71a2 to 71d2 constitute a set of support members corresponding to set S1 of the above embodiment, and support the yoke 930B from the +Z direction even without the yoke 930B. When viewed from the front of the paper in Figure 8, the angle that support members 71a2 and 71b2 make with the Z axis is preferably greater than 0 degrees and less than 90 degrees, and more preferably between 45 degrees and less than 90 degrees. This configuration allows for miniaturization of the device while supporting the yoke 930B with appropriate strength. Furthermore, when viewed from the front of the paper in Figure 8, the angle that support members 71c2 and 71d2 make with the Z axis is preferably greater than -90 degrees and less than 0 degrees, and more preferably greater than -90 degrees and less than or equal to -45 degrees. This configuration allows for miniaturization of the device while supporting the yoke 930B with appropriate strength.

[0071] Support members 71e2 to 71h2 constitute a set of support members corresponding to set S2 of the above embodiment, and support the yoke 930B from the -Z direction even without the yoke 930B. The angle that support members 71e2 and 71f2 make with the Z-axis, viewed from the plane of the paper in Figure 8, is preferably greater than 90 degrees and less than 180 degrees, and more preferably between 135 degrees and less than 180 degrees. This configuration allows for miniaturization of the device while supporting the yoke 930B with appropriate strength. Furthermore, the angle that support members 71g2 and 71h2 make with the Z-axis, viewed from the plane of the paper in Figure 8, is preferably greater than -180 degrees and less than -90 degrees, and more preferably greater than -180 degrees and less than or equal to -135 degrees. This configuration allows for miniaturization of the device while supporting the yoke 930B with appropriate strength.

[0072] The support section 970 further includes a set of at least two support members that support the yoke 930A from the Z direction only. In this modified example, the support section 970 includes support members 71i1, 71j1, 71k1, and 71l1. The support section 970 also further includes a set of at least two support members that support the yoke 930B from the Z direction only. In this modified example, the support section 970 includes support members 71i2, 71j2, 71k2, and 71l2. By providing support members that support the yokes 930A and 930B from the Z direction only, the vibration of the yokes 930A and 930B when transporting the superconducting electromagnet device 901 can be effectively suppressed. In addition, in the superconducting electromagnet device 1 of the above embodiment, the support section 70 may also include a set of at least two support members that support the yoke 30 from the Z direction only.

[0073] The support section 970 further includes a set of at least two support members that support the yoke 930A from the X direction only. In this modified example, the support section 970 includes support members 71m1, 71n1, 71o1, and 71p1. The support section 970 also further includes a set of at least two support members that support the yoke 930B from the X direction only. In this modified example, the support section 970 includes support members 71m2, 71n2, 71o2, and 71p2. By providing support members that support the yokes 930A and 930B from the X direction only, the vibration of the yokes 930A and 930B when transporting the superconducting electromagnet device 901 can be effectively suppressed. In addition, in the superconducting electromagnet device 1 of the above embodiment, the support section 70 may also include a set of at least two support members that support the yoke 30 from the X direction only.

[0074] Furthermore, in this embodiment, when viewed from the Z direction (from the front of the page in Figure 7), a virtual straight line passing through the support members 71m1, 71n1, 71o1, and 71p1 that support the yoke 930A only from the X direction passes through the center of gravity G1 of the yoke 930A and the coil fixed to the yoke 930A. This suppresses the rotation of the yoke 930A due to the electromagnetic force of the coil fixed to 930A. Similarly, when viewed from the Z direction (from the front of the page in Figure 7), a virtual straight line passing through the support members 71m2, 71n2, 71o2, and 71p2 that support the yoke 930B only from the X direction passes through the center of gravity G2 of the yoke 930B and the coil fixed to the yoke 930B. This suppresses the rotation of the yoke 930B due to the electromagnetic force of the coil fixed to 930B.

[0075] Furthermore, in this embodiment, the support section 970 includes a set of support members corresponding to the set S1 of the above embodiment, which includes support members 71a1 to 71d1. The distance between the fixing positions of support members 71a1 and 71b1 to the yoke 930A is greater than the distance between the fixing positions of support members 71c1 and 71d1 to the yoke 930A. Also, the width W1 in the X direction of the yoke 930A at the Y-direction position where support members 71a1 and 71b1 are provided is greater than the width W2 in the X direction of the yoke 930A at the Y-direction position where support members 71c1 and 71d1 are provided. In other words, the distance in the X direction between the fixing positions of two support members provided at the same Y-direction position (height) to the yoke is greater the greater the width of the yoke in the X direction at the same Y-direction position. As a result, the rotation of the yoke around the Y axis can be suppressed by having a larger distance between the fixing positions at positions where the width of the yoke is large.

[0076] The present invention has been described above based on each embodiment. However, the present invention is not limited to the above embodiments, and modifications may be made without departing from the spirit of the invention. Furthermore, the technologies described in each embodiment may be combined as appropriate, or known technologies may be combined with the technologies of the above embodiments as appropriate. [Explanation of Symbols]

[0077] 1 superconducting electromagnet device, 10 vacuum vessels, 20 pairs of superconducting electromagnets, 30 yokes

Claims

1. A deflection electromagnet device, A vacuum vessel that forms a vacuum space inside, A pair of superconducting coil units provided in the vacuum space, wherein each superconducting coil unit includes at least one coil, The pair of superconducting coil units includes at least one yoke to which the coils are fixed, The yoke on which the coil is fixed is supported by a plurality of support members relative to the vacuum vessel so as to avoid thermal contact with the vacuum vessel, Equipped with, A beam path through which a charged particle beam passes is formed between the pair of superconducting coil units. The pair of superconducting coil units are configured to generate an effective magnetic field region in a direction perpendicular to the direction of propagation of the charged particle beam (Z direction), At least one of the plurality of support members supports the yoke from a first direction, When the vertical direction is defined as the Y direction, and the direction perpendicular to the Y and Z directions is defined as the X direction, the first direction is a direction that has a predetermined angle with respect to the Y and Z directions. Bending electromagnet device.

2. A deflection electromagnet device according to claim 1, The aforementioned plurality of support members are A first set including at least three support members that support the yoke from at least the +Z direction, A second set including at least three support members that support the yoke from at least the -Z direction, including, Bending electromagnet device.

3. A deflection electromagnet device according to claim 2, The first set is, The yoke is supported by at least two support members from the +Y direction and the +Z direction, The yoke is supported by at least one support member from the -Y direction and the +Z direction, Includes, The second set mentioned above is, The yoke is supported by at least two support members from the +Y direction and the -Z direction, The yoke is supported by at least one support member from the -Y direction and the -Z direction, including, Bending electromagnet device.

4. A deflection electromagnet device according to claim 3, At least two support members that support the yoke from at least the +Y direction and the +Z direction have an angle of 45 degrees or more and less than 90 degrees with respect to the Z axis when viewed from the -X direction. At least two support members that support the yoke from at least the -Y direction and the +Z direction have an angle with respect to the Z axis greater than -90 degrees and less than or equal to -45 degrees when viewed from the -X direction. At least two support members that support the yoke from at least the +Y direction and the -Z direction have an angle with respect to the Z axis greater than 90 degrees and 135 degrees or less when viewed from the -X direction. At least two support members that support the yoke from at least the -Y direction and the -Z direction have an angle with respect to the Z axis of -135 degrees or more and less than -90 degrees when viewed from the -X direction. Bending electromagnet device.

5. A deflection electromagnet device according to claim 2, The support members included in the first set and the support members included in the second set each support the yoke from directions including components in the X, Y, and Z directions. Bending electromagnet device.

6. A deflection electromagnet device according to claim 2, The plurality of support members further include a third set comprising at least two support members that support the yoke only from the Z direction, Bending electromagnet device.

7. A deflection electromagnet device according to claim 2, The plurality of support members further include a fourth set comprising at least two support members that support the yoke only from the X direction, Bending electromagnet device.

8. A deflection electromagnet device according to claim 7, When viewed from the Z direction, a virtual straight line passing through the support member included in the fourth set passes through the center of gravity of the yoke and the pair of superconducting coil units. Bending electromagnet device.

9. A deflection electromagnet device according to claim 2, Each support member of the first set is fixed to the side of the yoke in the +Z direction, Each support member of the second set is fixed to the side of the yoke in the -Z direction. Bending electromagnet device.

10. A deflection electromagnet according to claim 3, The first set includes at least three support members, which are fixed to the yoke at a first position in the Y direction, and third and fourth support members, which are fixed to the yoke at a second position in the Y direction. The distance between the first and second support members in the X direction is greater than the distance between the third and fourth support members in the X direction. The width of the yoke in the X direction at the first position in the Y direction is greater than the width of the yoke in the X direction at the second position in the Y direction. Bending electromagnet device.

11. A deflection electromagnet device according to claim 3, Each of the following includes at least one support member that supports the yoke of the first set from at least the -Y direction and the +Z direction, and at least one support member that supports the yoke of the second set from at least the -Y direction and the -Z direction, and an elastic member that displaces in accordance with the thermal contraction of the yoke between at least one of the vacuum vessel and the yoke, Bending electromagnet device.

12. A charged particle beam irradiation device comprising the superconducting electromagnet device described in claim 1.

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