TW201927366A - Accelerator and particle beam therapy apparatus - Google Patents

Abstract

Provided is an accelerator equipped with a rotary capacitor capable of performing frequency modulation of a high frequency electric field in correspondence with different emission energies for each rotation direction. The accelerator includes an acceleration electrode for accelerating charged particles, an acceleration cavity for supplying electric power to the acceleration electrode to generate a high frequency electric field, and a rotating capacitor for modulating the resonance frequency of the acceleration cavity. The rotating capacitor rotates both in a forward direction and in a reverse direction, and provides temporal variation in electrostatic capacity different at each rotation direction. Frequency modulation is performed by making temporal variations in electrostatic capacitance different at each rotation direction correspond to different emission energies.

Description

Accelerator and particle beam therapy device

The present invention relates to an accelerator provided with a condenser and a particle beam therapy device.

In recent years, a particle beam treatment in which a particle beam such as a proton beam or a carbon beam is irradiated to a tumor for treatment has attracted attention. In particle beam therapy, in order to generate particle beams, an accelerator that accelerates charged particles to high energy is used. The accelerator system forms a high-frequency electric field synchronized with the spiraling frequency of the charged particles, and accelerates the charged particles to a predetermined energy. In order to accelerate the charged particles to a predetermined energy, the frequency of the high-frequency electric field must be adjusted to be consistent with the winding frequency of the charged particles. Therefore, an accelerator equipped with a rotary capacitor that performs frequency modulation of a high-frequency electric field has been developed. Patent Document 1 discloses an accelerator provided with a rotary capacitor capable of suppressing eddy currents and reducing heat generation.

[Prior technical literature] [Patent Literature]

Patent Document 1: Japanese Patent Application Publication No. 2013-157556

However, in order to accelerate the charged particles to a predetermined energy, appropriate frequency modulation is required according to the amount of energy. If a conventional rotating capacitor is used, it may be difficult to perform frequency modulation of a high-frequency electric field corresponding to different energy problem.

The present invention has been developed by a researcher in order to solve the above-mentioned problems, and an object thereof is to provide an accelerator equipped with a rotary capacitor capable of achieving different energy of corresponding charged particles to perform frequency modulation of a high-frequency electric field. Another object of the present invention is to provide a particle beam therapy device including an accelerator.

The accelerator of the present invention includes: an acceleration electrode that accelerates charged particles; an acceleration cavity that supplies electricity to the acceleration electrode to generate a high-frequency electric field; and a rotating capacitor that has a bidirectional rotation in a forward direction and a reverse direction. The rotating electrode and the fixed electrode arranged opposite to the rotating electrode perform frequency modulation of the high-frequency electric field corresponding to the first emitted energy of the charged particles by forward rotation, and perform reverse rotation. Frequency modulation of the high-frequency electric field corresponding to the second emitted energy of the charged particles.

In addition, the particle beam therapy device of the present invention is provided with: an accelerator having a rotary capacitor that performs frequency modulation in accordance with the output energy in each direction of forward and reverse rotation; The particle beams emitted from the accelerator; and the irradiating unit is configured to shape the particle beams supplied from the beam transfer unit into an irradiation area and irradiate the object to be irradiated.

The accelerator according to the present invention is provided with a rotating capacitor that performs frequency modulation of a high-frequency electric field according to different emission energy of each rotation direction, thereby achieving particle beams with efficient emission of different energy. In addition, the particle beam treatment device according to the present invention is provided with particle beams that can emit different energies, whereby particle beams of appropriate energy can be irradiated according to the type and location of a tumor.

1‧‧‧ accelerator

2a, 2b‧‧‧‧coil

3a, 3b ‧‧‧ magnetic pole

4‧‧‧Acceleration electrode

5‧‧‧Acceleration cavity

5a‧‧‧Inner conductor

5b‧‧‧outer conductor

6‧‧‧ exit channel

7‧‧‧ ion source

8‧‧‧ spiral track

9‧‧‧ high frequency power supply

10‧‧‧Rotating capacitor

11‧‧‧rotating electrode

11a, 11b, 12a, 12b

12‧‧‧ fixed electrode

13‧‧‧rotation axis

14‧‧‧ Motor

15‧‧‧ forward

16‧‧‧ reverse

17‧‧‧incident control device

20‧‧‧ Beam Conveyor

30‧‧‧Irradiation Department

41‧‧‧pitch

100‧‧‧ Particle Ray Therapy Device

111‧‧‧ center of rotation

112, 112a, 112b, 121‧‧‧ front end

113, 123‧‧‧ center axis

122, 122a, 122b ‧‧‧ Inner periphery

C, C1, C2‧‧‧ electrostatic capacitor

d‧‧‧Distance between electrodes

E‧‧‧Energy

E1, E2‧‧‧ exit energy

f‧‧‧winding frequency

fr‧‧‧ resonance frequency

L‧‧‧Inductance

r‧‧‧ orbit radius

S‧‧‧ facing area

T‧‧‧Acceleration time

t1‧‧‧ at incident

t2‧‧‧ When shooting

ω‧‧‧ rotation speed

Fig. 1 is a schematic plan sectional view of an accelerator according to a first embodiment of the present invention.

Fig. 2 is a schematic side sectional view of an accelerator according to the first embodiment of the present invention.

Fig. 3 is a schematic configuration diagram of a rotary capacitor according to a first embodiment of the present invention.

Fig. 4 is a schematic configuration diagram of a rotary electrode according to the first embodiment of the present invention.

Fig. 5 is a schematic configuration diagram of a fixed electrode according to the first embodiment of the present invention.

Fig. 6 is a graph showing the relationship between the electrostatic capacitance and the rotation angle of the rotary capacitor according to the first embodiment of the present invention.

FIG. 7 is a diagram showing a relationship between time changes in the electrostatic capacitance of the rotary capacitor according to the first embodiment of the present invention.

Fig. 8 shows a rotary capacitor which determines the first embodiment of the present invention. Step diagram of an example of the steps of the shape.

Fig. 9 is a graph showing the relationship between the orbit radius and the magnetic field strength in the first embodiment of the present invention.

Fig. 10 is a graph showing the relationship between the acceleration time and the winding frequency in the first embodiment of the present invention.

Fig. 11 is a graph showing the relationship between the acceleration time and the electrostatic capacitance in the first embodiment of the present invention.

Fig. 12 is an explanatory diagram for explaining a rotary capacitor according to the first embodiment of the present invention.

Fig. 13 is a graph showing the relationship between the acceleration time and the time change rate of the facing area in the first embodiment of the present invention.

Fig. 14 is a diagram showing a schematic configuration of a fixed electrode according to the first embodiment of the present invention.

Fig. 15 is a diagram showing a schematic configuration of a rotary electrode according to the first embodiment of the present invention.

Fig. 16 is a diagram showing a schematic configuration of a fixed electrode according to the first embodiment of the present invention.

Fig. 17 is a diagram showing a schematic configuration of an accelerator according to a second embodiment of the present invention.

Fig. 18 is a schematic configuration diagram showing a time change of an electrostatic capacitance of a rotary capacitor according to a second embodiment of the present invention.

Fig. 19 is a schematic configuration diagram of a particle beam therapeutic apparatus according to a third embodiment of the present invention.

Embodiments of the present invention will be described with reference to the drawings. The following description uses a synchro cyclotron (hereinafter referred to as an accelerator) as an example.

(Embodiment 1)

Fig. 1 is a schematic plan sectional view of an accelerator for carrying out the first embodiment of the present invention. Fig. 2 is a schematic side sectional view of an accelerator for implementing the first embodiment of the present invention. As shown in FIGS. 1 and 2, the accelerator 1 includes: a pair of coils 2 a and 2 b; a pair of magnetic poles 3 a and 3 b; an acceleration electrode 4; an acceleration cavity 5; an exit channel 6; and a rotary capacitor 10 .

The accelerator 1 generates a magnetic field between the magnetic poles 3a and 3b arranged apart from each other by applying a current to the coils 2a and 2b. In addition, high-frequency power is supplied to the acceleration electrode 4 through the acceleration cavity 5 to generate a high-frequency electric field. With the generated electric field, the charged particles injected from the ion source 7 (not shown) are spirally moved between the magnetic poles 3 a and 3 b in a spiral-shaped spiral orbit 8. Each time a charged particle passes through the gap 41 of the acceleration electrode 4, it is accelerated by a high-frequency electric field synchronized with the swirling frequency of the charged particle to increase its energy. With the increase of the energy of the charged particle system, the radius of the spiral orbit 8 will gradually increase, and when it reaches a predetermined energy, it will be emitted from the exit channel 6 as a particle line.

The acceleration cavity 5 includes: an inner conductor 5a; and an outer conductor 5b, which is cylindrical and arranged on the same axis. The inner conductor 5a is electrically connected to the acceleration electrode 4, and supplies high-frequency power from a high-frequency power source 9 (not shown) to the acceleration electrode 4. The acceleration cavity 5 has the original resonance frequency. The high-frequency power is supplied to the acceleration electrode 4 so that a high-frequency electric field corresponding to a resonance frequency is generated inside. The resonance frequency fr of the acceleration cavity 5 is determined by the formula (1) by the inductance L and the electrostatic capacitance C of the acceleration cavity 5.

As the charged particle system is accelerated, the mass will increase due to the relativistic effect, and the winding frequency will decrease. The acceleration cavity 5 is matched with the reduction of the winding frequency, and the electrostatic capacitance is increased by the rotating capacitor 10, thereby reducing the resonance frequency.

The rotary capacitor 10 includes a rotary electrode 11, a fixed electrode 12, and a rotary shaft 13. The rotating electrode 11 is electrically connected to the inner conductor 5a of the acceleration cavity 5, and the fixed electrode 12 is electrically connected to the outer conductor 5b. The rotary capacitor 10 includes at least one set of a rotating electrode 11 and a fixed electrode 12 and is alternately stacked in the axial direction of the rotating shaft 13. The rotating capacitor 10 rotates the rotating electrode 11 continuously and at a high speed, so that the electrostatic capacitance is periodically changed to obtain the resonance frequency of the acceleration cavity 5 synchronized with the rotating frequency of the charged particles.

Fig. 3 is a schematic configuration diagram of a rotary capacitor for implementing the first embodiment of the present invention. Fig. 3 is a rotary capacitor when viewed from the AA 'plane of Figs. As shown in FIG. 3, the rotating electrode 11 and the fixed electrode 12 each have at least one blade and are arranged to face each other. The rotating electrode 11 is driven by a motor 14 and is rotated through The shaft 13 rotates continuously in high speed in two directions of forward 15 and reverse 16 respectively. The motor 14 controls a rotation direction and a rotation speed by a signal from a control unit (not shown).

Fig. 4 is a schematic configuration diagram of a rotary electrode for a rotary capacitor according to a first embodiment of the present invention. As shown in FIG. 4, the rotating electrode 11 is provided so as to extend radially from the rotating shaft 13 to the outside in the radial direction. The blades of the rotating electrode 11 are formed asymmetrically with respect to the central axis 113 (hereinafter referred to as the central axis) of the center position of the front end 112 passing radially outward from the rotation center 111. For example, the side edge 11a extending from one end of the blade front end portion 112 toward the inside in the radial direction is formed so as to be curved toward the opposite side edge 11b.

Fig. 5 is a schematic configuration diagram of a fixed electrode of a rotary capacitor for carrying out the first embodiment of the present invention. As shown in FIG. 5, the fixed electrode 12 has, for example, a circular outer periphery that is concentric with the rotation center 111, and is provided so as to extend from the outer periphery toward the inside in the radial direction. The blade of the fixed electrode 12 includes a front end portion 121 constituting a part of the outer periphery, and side edges 12 a and 12 b extending from both ends of the front end portion 121 toward the inside in the radial direction.

Here, although FIG. 3, FIG. 4, and FIG. 5 show an example where the number of blades of the rotating electrode 11 and the fixed electrode 12 is four, the number of blades may be changed as appropriate.

FIG. 6 is a diagram showing the relationship between the rotation angle and the electrostatic capacitance of the rotary capacitor according to the first embodiment of the present invention. Here, the rotating electrode 11 and the fixed electrode 12 are each constituted by a single blade. In addition, it is set to rotate in the forward direction 15 and the rotation angle is to rotate the rotation electrode 11 Among the facing sides 11a and 11b of the blade, the side 11a of the positive side in the direction of rotation and the facing side 12a and 12b of the fixed electrode 12 overlap with the side 12b of the negative side in the direction of rotation The position is set to 0 degrees of the reference.

As shown in FIG. 6, as the rotation capacitor 10 increases, the opposing area of the blades of the rotating electrode 11 and the blades of the fixed electrode 12 also increases, and the electrostatic capacitance also increases. The electrostatic capacitance of the rotary capacitor 10 is maximized at, for example, the rotation angle θ 1, and decreases as the facing area decreases. The electrostatic capacitance is the direction of rotation of the negative side 11b of the rotating side 11 of the blades facing the sides 11a, 11b, and the side of the fixed electrode 12 facing the side 12a, 12b of the rotating electrodes 11 The rotation angle θ 2 at which the side 12 a on the front side is detached is minimized.

Fig. 7 (a) shows the time change of the electrostatic capacitance when the rotary capacitor for implementing the first embodiment of the present invention is rotated once in a forward direction at a predetermined rotation speed. In addition, Fig. 7 (b) shows the time variation of the electrostatic capacitance when the rotary capacitor for implementing the first embodiment of the present invention is rotated once in the reverse direction at the same rotation speed as in Fig. 7 (a). As shown in Figs. 7 (a) and 7 (b), by forming the blades of the rotating electrode 11 asymmetrically with respect to the central axis 113, the rotating capacitor 10 can be different in the forward direction 15 and the reverse direction 16 Time variation of electrostatic capacitance. Thereby, the time changes of the electrostatic capacitances in the forward direction 15 and the reverse direction 16 can be different, and the frequency can be adjusted corresponding to different output energy.

When the charged particles are emitted with the outgoing energy E1, the accelerator 1 rotates the rotary capacitor 10 in the forward direction 15 and increases the electrostatic capacitance from the incident time t1 of the charged particles to the emitted time t2 to perform the high-frequency electric field. Frequency modulation. In addition, when the charged particles are emitted with the output energy E2, the accelerator 1 rotates the rotary capacitor 10 in the reverse direction 16 and increases the electrostatic capacitance from the incident time t'1 of the charged particles to the emitted time t'2 to achieve high Frequency modulation of the frequency electric field.

In this way, the rotary capacitor 10 is rotated in the forward 15 and reverse 16 directions, and the time variation of the electrostatic capacitance corresponding to different output energy is obtained according to each rotation direction, so that the accelerator 1 can efficiently emit particle lines with different output energy.

Next, an example of a method of determining the shape of the rotary capacitor 10 in order to obtain the time variation of the electrostatic capacitance suitable for different emitted energy for each rotation direction will be described. Fig. 8 is a step diagram showing an example of a procedure for determining the shape of the rotary capacitor for implementing the first embodiment of the present invention. The rotating capacitor 10 is, for example, a time change of an electrostatic capacitance obtained when a forward rotation of 15 is suitable for emitting energy of 215 MeV and a reverse rotation of 16 is suitable for emitting energy of 160 MeV (step S1).

It is assumed that the maximum magnetic field strength of the accelerator 1 is 6T, and the magnetic field distribution with respect to the orbit radius is determined according to each emitted energy (step S2). In order to accelerate the charged particles stably, the magnetic field strength of the accelerator 1 is distributed according to the principle of weak convergence so that it decreases as the orbit radius increases. Fig. 9 shows the magnetic field strength with respect to the orbit radius in the first embodiment for carrying out the present invention. As shown in FIG. 9, with respect to the magnetic field strength of the orbit radius, the emission energy of 160 MeV is set to be smaller than the emission energy of 215 MeV. The magnetic field strength is adjusted by, for example, a current applied to the coils 2a, 2b.

The winding frequency with respect to the acceleration time is calculated from the set magnetic field distribution (step S3). Here, the acceleration time refers to the time it takes for the charged particles to enter the accelerator 1 until they are emitted. Herein, the charged particles are set to protons, and the orbital radius at the initial stage of acceleration is set to r. The winding frequency of the charged particles in the acceleration time T is determined by formulas (2) to (6).

E = E + dE … formula (2)

T ( r ' ) = Σt ( r' ) ... Equation (6)

However, E is the energy of the charged particles, dE is the energy that increases every 1 round, M ₀ is the mass of the charged particles in the early stage of acceleration, B (r) is the magnetic field strength in the early stage of acceleration, and B (r ') Magnetic field strength in system orbit radius r ', E (r') energy of charged particles in orbit radius r ', f (r') coiling frequency in orbit radius r ', t (r') orbit radius The winding period in r 'and the acceleration time in T (r') orbit radius r '.

The energy E of the charged particles is calculated from the formula (2) based on the orbit radius r at the initial acceleration. From formula (3), the orbit radius r 'is calculated from the energy E of the charged particles to be increased. The winding frequency f (r ') at the orbit radius r is obtained from the formula (4). Calculate the time required for one lap from formula (5). From equations (4) and (6), the time T (r ') for the orbit radius r' from the initial acceleration period is calculated. In this way, the winding frequency in the acceleration time T can be obtained.

Fig. 10 is a winding frequency with respect to an acceleration time for implementing the first embodiment of the present invention. As shown in Fig. 10, when the emission energy of the charged particles is set to 215 MeV, the winding frequency is 89 MHz at the initial acceleration and 67 MHz at the time of emission, and the required frequency modulation amplitude is 22 Hz. In addition, when the emission energy is set to 160 MeV, the winding frequency is 78 MHz at the initial acceleration and 62 MHz at the time of emission, and the required frequency modulation amplitude is 16 MHz.

From the calculated winding frequency with respect to the acceleration time and formula (1), the electrostatic capacitance with respect to the acceleration time is calculated (step S4). FIG. 11 is an electrostatic capacitance with respect to an acceleration time for implementing the first embodiment of the present invention. As shown in FIG. 11, the rotating capacitor 10 performs a frequency modulation of 22 Hz when rotating in the forward direction 15 and a frequency modulation of 16 MHz when rotating in the reverse direction 16 to make the electrostatic capacitance relative to the acceleration time. increase.

From the calculated electrostatic capacitance with respect to the acceleration time, a time change rate of the opposing areas of the rotating electrode 11 and the fixed electrode 12 of the rotary capacitor 10 with respect to the acceleration time is calculated (step S5). Here, as shown in FIG. 12, the rotation speed of the rotary capacitor 10 is set to 7500 rpm, the number of laminations in the rotation axis direction of the rotating electrode 11 and the fixed electrode 12 is 5 groups, and the number of blades is 4 each. The rotating electrode The distance between 11 and the fixed electrode 12 is 2 mm. The electrostatic capacitance C of the rotary capacitor 10 is determined by the formula (7) based on the facing area S of the rotary electrode 11 and the fixed electrode 12, the distance d between the electrodes, and the dielectric constant ε _{0 of the} vacuum.

From the formula (7), the electrostatic capacitance with respect to the acceleration time shown in FIG. 11 can be expressed by the time change rate of the opposing area with respect to the acceleration time. FIG. 13 is a time change rate of the facing area of the rotary capacitor in accordance with the first embodiment of the present invention with respect to the acceleration time.

The shapes of the rotating electrode 11 and the fixed electrode 12 are determined based on the time change rate of the facing area with respect to the acceleration time shown in FIG. 13 (step S6).

As an example, as shown in FIG. 14, the rotating electrode when the center axis 123 of the center position of the front end 121 of the blade of the fixed electrode 12 from the rotation center 111 of the rotating electrode 11 with respect to the blade of the fixed electrode 12 is symmetrical is determined. 11 shapes. When the fixed electrode 12 is symmetrical with respect to the central axis 123, the time change rate dS / dt of the facing area S is determined by the distance from the rotation center 111 of the rotating electrode 11 to the blade of the rotating electrode 11. The length l and the rotation speed ω up to the distal end portion 112 are determined by the formula (8).

It is known from the formula (8) that the length from the rotation center 111 of the rotary electrode 11 to the front end portion 112 can be determined from the time change rate of the facing area. Fig. 15 (a) is a schematic configuration diagram showing an example of a rotary electrode for implementing the first embodiment of the present invention. Fig. 15 (b) is a schematic configuration diagram showing an example of the shape of a blade of a rotating electrode for implementing the first embodiment of the present invention. As shown in Figs. 15 (a) and (b), the rotating electrode 11 is relative to the direction of rotation so that the length from the center of rotation 111 to the front end 112 meets the time change rate of the opposing area with respect to the acceleration time. Changing shape.

The front end portion 112 of the blade of the rotating electrode 11 is curved toward the inside in the radial direction in an asymmetrical manner with respect to the central axis 113. The rotating electrode 11 is curved, for example, so that the front end portion 112 a having one side with respect to the central axis 113 satisfies the time change rate of the facing area of the emitted energy 215 MeV. In addition, it is curved so that the front end portion 112b on the other side with respect to the central axis 113 satisfies the time change rate of the facing area of the outgoing energy of 160 MeV.

The rotating electrode 11 is formed in this way, so that the accelerator 1 can achieve that when the 215 MeV particle line is emitted, the rotating electrode 11 is rotated in the forward direction 15 and the center axis 113 relative to the rotating electrode 11 is used as one of them The front end portion 112a on one side performs frequency modulation, and when a 160 MeV particle beam is emitted, the rotating electrode 11 is rotated in the reverse direction 16 and the front end portion 112b on the other side is used to perform frequency modulation with respect to the central axis 113. .

Here, although the fixed electrode 12 is symmetrical with respect to the central axis 123 and the rotating electrode 11 is asymmetric with respect to the central axis 113, the shape of the blade of the rotating electrode 11 may be symmetrical and the blade of the fixed electrode 12 may be set. The shape is set to asymmetric. Fig. 16 (a) is a schematic configuration diagram showing an example of a fixed electrode for implementing the first embodiment of the present invention. Fig. 16 (b) is a schematic configuration diagram showing an example of the shape of a blade of a fixed electrode for implementing the first embodiment of the present invention. As shown in FIG. 16 (a) and FIG. 16 (b), the fixed electrode 12 has a length from the rotation center 111 of the rotating electrode 11 to the inner peripheral portion 122 of the fixed electrode 12, and satisfies the opposing area relative to acceleration The method of the time change rate of time is a shape that changes with respect to the direction of rotation.

For example, the inner peripheral portion 122 of the blade of the fixed electrode 12 is curved toward the outside in the radial direction in an asymmetrical manner with respect to the central axis 123. The fixed electrode 12 is bent, for example, such that the inner peripheral portion 122a on one side with respect to the central axis 123 satisfies the time variation of the facing area of the emitted energy 215 MeV. In addition, the inner peripheral portion 122b on the other side with respect to the center axis 123 is bent so as to satisfy the emission energy of 160 MeV.

The fixed electrode 12 is formed in this way, so that the accelerator 1 can achieve that when the 215 MeV particle line is emitted, the rotating electrode 11 is rotated in the forward direction 15 and the inner peripheral portion 122 a of which is one side relative to the central axis 123 of the fixed electrode 12 While performing frequency modulation, and when 160MeV is emitted, The rotating electrode 11 is rotated in the reverse direction 16 and the frequency is adjusted by the inner peripheral portion 122 b on the other side with respect to the central axis 113.

Here, although an example in which the rotating electrode 11 or the fixed electrode 12 is symmetrical with respect to the central axes 113 and 123 is shown, as long as the rotating capacitor 10 satisfies the time variation of the electrostatic capacitance corresponding to different emitted energy according to each rotation direction The method may be formed, and the rotating electrode 11 and the fixed electrode 12 may be asymmetric with respect to the central axes 113 and 123, respectively.

In summary, the accelerator 1 of this embodiment is configured to include a rotary capacitor 10 that rotates in a forward direction 15 and a reverse direction 16 and correspondingly emits differently charged particles in each direction of rotation. Energy causes the electrostatic capacitance to change over time. With this configuration, the accelerator 1 can achieve particle rays that efficiently generate different energies.

In addition, the shape of the rotating electrode 11 of the rotating capacitor 10 is preferably formed in consideration of the stability of the machine against high-speed rotation. For example, the difference between the rotation angle θ1 until the maximum capacitance is shown in FIG. 6 and the angle θ2-θ1 between the rotation angle θ1 where the capacitance is maximum and the rotation angle θ2 when the capacitance is minimum is formed as 0. <| Θ2-1 | / θ1 | ≦ 10%. Thereby, in order to tune the resonance frequency of the acceleration cavity 5, when the rotating electrode 11 is rotated at a high speed of 1000 rpm or higher, for example, rotation can be achieved while ensuring stability.

(Embodiment 2)

The accelerator 1 for implementing the second embodiment of the present invention will be described. Here, the description overlapping with the accelerator 1 of the first embodiment is appropriately simplified. Change or omit. In this embodiment, the configuration of the first embodiment further includes a configuration of an incident control device 17.

Fig. 17 is a schematic configuration diagram of an accelerator for implementing a second embodiment of the present invention. The incident control device 17 controls the timing of injecting the charged particles from the ion source 7 into the accelerator 1. The incident control device 17 outputs, for example, the signal of the charged particles to the ion source 7 by detecting the electrostatic capacitance of the rotary capacitor 10 so that the electrostatic capacitance increases from the incidence of the charged particles to the time of emission.

FIG. 18 (a) and FIG. 18 (b) are diagrams showing the relationship between the change in the electrostatic capacitance when the rotary capacitor used to implement the second embodiment of the present invention is rotated in the forward and reverse directions, respectively. As shown in FIG. 18 (a), when the output energy E1 of the rotary capacitor 10 is continuously rotated in the forward direction 15, the electrostatic capacitance of the rotary capacitor 10 is output whenever the electrostatic capacitance C1 corresponding to the winding frequency at the initial acceleration is output. Signal A of the incident charged particles. In addition, as shown in FIG. 18 (b), when the output energy E2 of the rotary capacitor 10 is continuously rotated in the reverse direction 16, the electrostatic capacitance of the rotary capacitor 10 becomes the electrostatic capacitance C2 corresponding to the winding frequency at the initial acceleration, A signal A that is incident on the charged particles is output. In this way, the incident control device 17 emits charged energy corresponding to each rotation direction, and periodically charges the charged particles into the accelerator 1 at a timing suitable for acceleration.

Here, as a method for setting the incident timing, although an example of detecting the electrostatic capacitance of the rotary capacitor 10 is shown, in addition to this, the rotation angle of the rotary capacitor 10, the electrostatic capacitance of the acceleration cavity 5, and the acceleration can also be detected. The resonance frequency of the cavity 5 and the like.

In this configuration, as in Embodiment 1, the accelerator 1 is provided with a rotary capacitor 10 that performs frequency modulation of the emitted energy of the charged particles in each direction of rotation, and can emit particle rays of different energies. Furthermore, in the present embodiment, it is configured to include an incident control device 17, which can periodically inject charged particles at a timing suitable for acceleration according to the magnitude of the output energy, and can efficiently emit different Particle lines of energy. In addition, the pulse-like charged particles can be continuously injected at a timing suitable for acceleration, and a sufficient amount of particle rays can be generated.

(Embodiment 3)

A particle beam therapy apparatus 100 for carrying out the third embodiment of the present invention will be described. In this embodiment, the accelerator 1 of Embodiment 1 or 2 is applied to the particle beam therapy apparatus 100. The description overlapping with the accelerator 1 of the first and second embodiments is appropriately simplified or omitted.

Fig. 19 is a schematic configuration diagram of a particle beam therapy apparatus for implementing a third embodiment of the present invention. As shown in FIG. 19, the particle beam treatment apparatus 100 includes: an accelerator 1; a beam transporting unit 20 that transports particle rays emitted through the accelerator 1; and an irradiation unit 30 that supplies particles supplied from the beam transporting unit 20. The line is formed as an irradiation area and irradiates the object.

The accelerator 1 is supplied with high-frequency power from a high-frequency power source 9 and forms a high-frequency electric field inside. The accelerator 1 determines the rotation direction of the rotary capacitor 10 according to a predetermined output energy, and modulates the frequency of the high-frequency electric field. The charged particles injected from the ion source 7 are accelerated to a predetermined energy by a high-frequency electric field after the frequency is adjusted by the rotary capacitor 10, and serve as particles. And shoot out.

The particle beams emitted by the accelerator 1 are emitted to the beam transfer unit 20. The beam conveyance unit 20 includes a vacuum passage that becomes a conveyance path of the particle beam, and a deflection electromagnet for deflecting the beam orbit of the particle beam at a predetermined angle. The irradiation unit 30 irradiates the object to be irradiated by forming the particle beams supplied from the beam transporting unit 20 into an irradiation area corresponding to the size or depth of the tumor to be treated.

The particle beam therapy device 100 according to the present embodiment is provided with an accelerator 1 having a rotary capacitor 10 that performs frequency modulation of the corresponding output energy in each of the rotation directions of forward 15 and reverse 16 so that That is, according to the size or depth of the tumor to be treated, the particle beam of appropriate energy can be efficiently irradiated. With the configuration in which particle rays of different energies can be emitted in the accelerator 1, compared with the case where the high-energy particle rays that were once generated are forcibly lowered outside the accelerator 1, energy waste can be saved, and efficient irradiation can be performed. Particle lines. Furthermore, the amount of radiation exposure to a patient can be reduced, and the burden on the patient can be reduced.

In the first to third embodiments, although the synchrocyclotron has been described as an example of the accelerator 1, other circular accelerators may be used.

Claims (9)

An accelerator includes: an acceleration electrode that accelerates charged particles; an acceleration cavity that supplies electricity to the acceleration electrode to generate a high-frequency electric field; and a rotating capacitor that has a bidirectional rotation in a forward direction and a reverse direction. The rotating electrode and the fixed electrode arranged opposite to the rotating electrode perform frequency modulation of the high-frequency electric field corresponding to the first emitted energy of the charged particles by the forward rotation, and the reverse is performed by the reverse The frequency of the high-frequency electric field corresponding to the second emitted energy of the charged particles is adjusted by rotating in the direction of rotation. The accelerator according to item 1 of the scope of patent application, wherein the rotating electrode system of the rotating capacitor has at least one blade and a central axis with respect to a center position of a front end of the blade passing through the rotating electrode from a center of rotation. Formed as asymmetric. The accelerator according to item 1 of the scope of patent application, wherein the fixed electrode system of the rotary capacitor has at least one blade and is centered relative to the center position of the front end of the blade passing from the rotation center through the fixed electrode. The axis is formed asymmetrically. The accelerator according to item 2 of the scope of patent application, wherein the fixed electrode system of the rotary capacitor has at least one blade and is centered relative to the center position of the front end of the blade passing from the rotation center through the fixed electrode. The axis is formed asymmetrically. Accelerator as described in item 1 of patent application scope, with incident control Device, the incident control device detects at least any one of the electrostatic capacitance, the rotation angle of the rotary capacitor, the electrostatic capacitance of the acceleration cavity, and the resonance frequency, and controls the timing of incidence of the charged particles. The accelerator according to item 2 of the scope of the patent application is provided with an incident control device that detects at least any one of the electrostatic capacitance, the rotation angle, the electrostatic capacitance of the acceleration cavity, and the resonance frequency of the rotating capacitor. To control the timing of incidence of the aforementioned charged particles. The accelerator according to item 3 of the scope of patent application is provided with an incident control device that detects at least any one of the electrostatic capacitance, the rotation angle, the electrostatic capacitance of the acceleration cavity, and the resonance frequency of the rotating capacitor. To control the timing of incidence of the aforementioned charged particles. The accelerator according to item 4 of the scope of the patent application is provided with an incident control device that detects at least any one of the electrostatic capacitance of the rotating capacitor, the rotation angle, the electrostatic capacitance of the acceleration cavity, and the resonance frequency. To control the timing of incidence of the aforementioned charged particles. A particle beam therapy device is provided with the accelerator described in any one of items 1 to 8 of the scope of patent application, and has a frequency adjustment for emitting energy corresponding to each of the rotation directions of the forward direction and the reverse direction. The aforementioned rotating capacitor is changed; a beam transporting unit transports particle beams emitted by the accelerator; and an irradiation unit is configured to shape the particle beams supplied from the beam transporting unit into an irradiation area and irradiate the object to be irradiated .