JP6448339B2 - Ion accelerator and particle beam therapy system - Google Patents

Description

  Embodiments described herein relate generally to an ion accelerator for accelerating an ion beam extracted from an ion source, and a particle beam therapy apparatus using the ion accelerator.

  As the ion source, there is a laser ion source using a laser. This laser ion source is an apparatus that generates ions by transporting ions contained in plasma as they are and accelerating them when extracting the ions (see, for example, Patent Documents 1 and 2). Therefore, the laser ion source can generate ions by irradiating the target with laser light, which is advantageous for generating large current and multivalent ions. Has been applied.

  Specifically, as shown in FIG. 9, the laser ion source 2 condenses the laser light 1 emitted from the laser transmitter 1a by a condenser lens through a plurality of mirrors (not shown) and irradiates the target 2a. . At the laser focusing point focused on the target 2a, a minute portion of the target 2a is heated to a high temperature. The portion heated to this high temperature is turned into plasma, and laser ablation plasma 2b is generated.

  This laser ablation plasma 2b is transported by a transport tube 2c, and a ground frequency high frequency quadrupole linear accelerator (hereinafter referred to as RFQ) 5, a drift tube linear accelerator (Drift). Only necessary ions are accelerated by the potential difference from the tube linac (hereinafter referred to as DTL) 13 and become an ion beam 6 that is incident on the RFQ 5 and DTL 13. The ion beam 6 is increased in energy by RFQ 5 and DTL 13, and is incident on a synchrotron (not shown) installed downstream thereof. The laser ion source 2 and the RFQ 5 are connected by a connecting portion 2d.

Japanese Patent No. 3713524 JP 2009-37764 A

  By the way, when the beam trajectory adjusting element by the electric and magnetic fields other than the transport tube 2c is not provided between the laser ion source 2 and the RFQ 5, the ion beam 6 drawn from the laser ion source 2 as shown in FIG. The beam trajectory is determined by the tip shape of the transport tube 2c (for example, the size of the hole and the thickness of the tip) and the positional relationship between the transport tube 2c and the components of the RFQ 5 (RFQ electrode 5a and RFQ end plate 5b). However, there is a problem that the beam size and convergence cannot be controlled.

  Therefore, when there is a change in the extraction current value or valence ratio drawn from the laser ion source 2, the incidence is made to match the acceptance of RFQ5 (the diameter of the received beam and the divergence angle are determined from the design). I can't let you. As a result, the number of ions that can be accelerated by RFQ5 decreases, and a necessary number of ions cannot be transported. In such a case, the beam size and the convergence can be finely adjusted by adjusting the positional relationship between the transport tube 2c and the RFQ 5.

  An equipotential surface shown in FIG. 10 is formed between the transport tube 2c, the RFQ electrode 5a, and the RFQ end plate 5b.

  However, in order to adjust the position of the transport tube 2c as described above, when the vacuum state is released, both the laser ion source 2 and the RFQ 5 are released to the atmosphere, and it takes half a day to start up the vacuum state again. It takes more time. Therefore, there is a problem that the adjustment work of the position of the transport pipe 2c becomes large.

  The problem to be solved by the embodiments of the present invention is to provide an ion accelerator and a particle beam therapy system capable of adjusting the position of a transport tube with respect to a linear accelerator while maintaining a vacuum state.

In order to solve the above problems, an ion acceleration apparatus according to the present embodiment accelerates an ion beam extracted from a laser ion source that extracts an ion beam from plasma generated by irradiation with laser light, and the laser ion source. A linear accelerator that connects the laser ion source and the linear accelerator while maintaining a vacuum state, and one side is fixed to the laser ion source, and the other side passes through the connection to the linear accelerator. The laser comprising: a transport tube that extends and transports an ion beam extracted from the laser ion source to the linear accelerator; and an expansion / contraction section that is provided in the connection section and expands and contracts in an axial direction of the connection section. the ion source was movable along the axial direction of the ion beam, to measure the movement distance along the axial direction of the ion beam of the laser ion source Characterized in that the distance meter is installed.

The particle beam therapy system according to this embodiment includes a laser ion source that extracts an ion beam from plasma generated by irradiating laser light, a linear accelerator that accelerates the ion beam extracted from the laser ion source, and the laser. A connection part for maintaining a vacuum state between the ion source and the linear accelerator, and one side is fixed to the laser ion source, and the other side extends through the connection part to the linear accelerator, and is connected to the laser ion source. A transport tube for transporting the extracted ion beam to the linear accelerator, an expansion / contraction part provided in the connection part and capable of expanding and contracting in the axial direction of the connection part, and the ion beam of the linear accelerator being transported. A synchrotron that circulates the beam and accelerates to a predetermined energy, and an ion beam accelerated by the synchrotron is extracted. And unloading equipment, and an irradiation device for irradiating the irradiation target with the ion beam extracted by said extraction device, the laser ion source is movable along the axial direction of the ion beam, the said laser ion source A distance meter for measuring the moving distance along the axial direction of the ion beam is installed .

  According to the embodiment of the present invention, it is possible to adjust the position of the transport tube with respect to the linear accelerator while maintaining the vacuum state.

It is a block diagram which shows an example of the heavy particle beam therapy apparatus which comprises the ion accelerator which concerns on embodiment of this invention. 1 is a schematic plan sectional view showing a first embodiment of an ion accelerator according to the present invention. FIG. 3 is a schematic vertical sectional view of FIG. 2. It is a schematic plan sectional view showing a second embodiment of the ion accelerator according to the present invention. FIG. 5 is a schematic vertical sectional view of FIG. 4. It is a schematic plane sectional view showing a third embodiment of the ion accelerator according to the present invention. FIG. 7 is a schematic vertical sectional view of FIG. 6. It is a flowchart which shows operation | movement of the control part of FIG. It is a schematic plan sectional view showing a conventional ion accelerator. It is the A section enlarged view of FIG.

  Hereinafter, an embodiment of an ion accelerator according to the present invention and an embodiment of a particle beam therapy system including the ion accelerator will be described with reference to the drawings.

  In the following embodiment, an example in which an embodiment of an ion accelerator is applied to a heavy ion beam therapy apparatus will be described. Moreover, in the following embodiment, the same code | symbol is attached | subjected and demonstrated to the part which is the same as that of the conventional structure, or respond | corresponds.

(Heavy particle therapy equipment)
FIG. 1 is a configuration diagram illustrating an example of a heavy particle beam therapy apparatus including an ion accelerator according to an embodiment of the present invention. In FIG. 1, the beam transport system is omitted.

  As shown in FIG. 1, the heavy particle beam therapy system 300 includes a linear accelerator 15, a synchrotron 40, a take-out device 35, an X-axis electromagnet 30a, and a Y-axis electromagnet 30b each composed of a laser ion source 2, an RFQ 5 and a DTL 13. , Vacuum duct 31, dose monitor unit 50, ridge filter 60, range shifter 70, controller 80, and the like. The X-axis electromagnet 30a, the Y-axis electromagnet 30b, the vacuum duct 31, the dose monitor unit 50, the ridge filter 60, the range shifter 70, and the controller 80 constitute the irradiation apparatus of this embodiment.

  The heavy particle beam therapy system 300 generates ions by accelerating the ions generated by the laser ion source 2 at a high speed by the linear accelerator 15 and the synchrotron 40, and this ion beam is applied to the affected part (tumor cell) 201 of the patient 200. It is a device that performs treatment by irradiating and acting ions. In the heavy particle beam therapy system 300, the affected part 201 can be discretized into three-dimensional lattice points, and a three-dimensional scanning irradiation method can be performed in which a narrow-diameter ion beam is sequentially scanned at each lattice point.

Specifically, the affected part 201 is divided into flat units called slices in the ion beam axial direction (Z-axis direction in the coordinate system shown in the upper right of FIG. 1), and the divided slices Z _i , slices Z _{i + 1} , Three-dimensional scanning is performed by sequentially scanning the two-dimensional lattice points (the lattice points in the X-axis and Y-axis directions in the coordinate system shown in the upper right of FIG. 1) of each slice such as the slice Z _{i + 2} .

  Ions generated by the laser ion source 2 are accelerated to energy that can reach deep inside the affected area 201 by the linear accelerator 15 and the synchrotron 40 to generate an ion beam. That is, the linear accelerator 15 accelerates ions generated by the laser ion source 2. The synchrotron 40 is transported with the ion beam of the linear accelerator 15, and circulates the ion beam to accelerate it to a predetermined energy.

  After completion of the acceleration of the ion beam, the ion beam is taken out by the take-out device 35 and transported from the emission trajectory (not shown) to the treatment room. The ion beam extracted by the extraction device 35 is irradiated to the affected area 201 that is the irradiation target by the irradiation device.

  Specifically, in the irradiation apparatus, the X-axis electromagnet 30a that scans in the X direction and the Y-axis electromagnet 30b that scans in the Y direction deflect the ion beam in the X-axis direction and the Y-axis direction and Are scanned in two dimensions. The range shifter 70 controls the position of the affected part 201 in the Z-axis direction.

  The range shifter 70 is composed of, for example, an acrylic plate having a plurality of thicknesses, and by combining these acrylic plates, the energy of the ion beam passing through the range shifter 70, that is, the range of the body, is determined by the position of the affected slice 201 slice in the Z-axis direction. Can be changed step by step. The size of the in-vivo range by the range shifter 70 is normally controlled to change at equal intervals, and this interval corresponds to the interval between lattice points in the Z-axis direction.

  As a method for switching the range of the body, in addition to a method of inserting an attenuation object on the path of the ion beam as in the range shifter 70, a method of changing the energy of the ion beam itself by controlling an upstream device may be used.

  The ridge filter 60 is provided for diffusing a sharp peak of the dose in the body depth direction called a Bragg peak. Here, the diffusion width of the Bragg peak by the ridge filter 60 is set to be equal to the thickness of the slice, that is, the interval between lattice points in the Z-axis direction. The ridge filter 60 for three-dimensional scanning irradiation is configured by arranging a plurality of aluminum rod-like members having a substantially isosceles triangle cross section. The peak of the Bragg peak can be diffused by the difference in path length generated when the ion beam passes through the isosceles triangle, and the diffusion width can be set to a desired value by the shape of the isosceles triangle.

  The dose monitor unit 50 is for monitoring the dose to be irradiated. In the case, the dose monitor unit 50 collects charges generated by the ionizing action of the heavy particle beam with parallel electrodes, and is disposed in the case. A secondary electron monitor (SEM) device that measures secondary electrons emitted from the secondary electron emission film is used.

(First embodiment of ion accelerator)
FIG. 2 is a schematic plan sectional view showing a first embodiment of the ion accelerator according to the present invention. FIG. 3 is a schematic sectional elevation view of FIG. In FIG. 2, the RFQ electrode 5 a and the RFQ end plate 5 b in the RFQ 5 are illustrated, but are not illustrated in other drawings.

  As shown in FIGS. 2 and 3, the laser ion source 2 has a vacuum vessel 20. The vacuum vessel 20 is made of a material that has excellent corrosion resistance and chemical resistance and emits less gas, such as stainless steel. Inside the vacuum vessel 20, an element to be an ion or a target 2a containing the element is installed. The target 2a is formed of, for example, a carbon column member or a plate member. When the target 2a is a cylindrical member, it is rotated to become a new surface every time the laser beam 1 is irradiated. Moreover, in the case of a plate-shaped member, it is comprised so that plane movement may be carried out by biaxial drive. In the present embodiment, an example in which a cylindrical member is used for the target 2a will be described.

  The laser ion source 2 irradiates the target 2a installed in the vacuum vessel 20 with the laser beam 1 emitted from the laser transmitter 1a to generate a laser ablation plasma 2b, and the ion beam 6 is generated from the laser ablation plasma 2b. Is pulled out. The laser beam 1 is configured to be condensed on the target 2a by a lens installed as an inside or outside of the vacuum vessel 20 or as a vacuum partition, thereby increasing the laser power density. Since the laser ablation plasma 2b has a high beam density in a direction perpendicular to the surface of the target 2a, a transport tube 2c and an RFQ 5 are provided in that direction.

  The laser ion source 2 and the RFQ 5 are connected by the connecting portion 2d while maintaining a vacuum state. An insulating tube 4 and a bellows 3 as an expansion / contraction part are connected to the connection part 2d in series in the axial direction. The bellows 3 is made of stainless steel and has stretchability and airtightness. The bellows 3 has a flange (not shown) fixed to both ends. The bellows 3 has one end fixed to the side surface of the laser ion source 2 via the flange and the other end connected to one end of the insulating tube 4. The other end of the insulating tube 4 is connected to the connection portion 2d.

  The transport tube 2c is formed in a long cylindrical shape, one side is fixed to the laser ion source 2, and the other side extends to the RFQ 5 through the bellows 3, the insulating tube 4 and the connecting portion 2d. The transport tube 2c transports the ion beam 6 extracted from the laser ion source 2 to the RFQ 5. The RFQ 5 accelerates the ion beam 6 extracted from the laser ion source 2 together with the DTL.

  The laser ion source 2 is installed on the gantry 7. An insulating portion 10 is attached to the bottom surface of the gantry 7. Thereby, the gantry 7 is supported by the insulating portion 10. Two rails 8 parallel to each other are laid on the upper surface of the gantry 7.

  The laser ion source 2 is placed on a pedestal (not shown). A plurality of traveling wheels (not shown) are attached to the bottom surface of the pedestal. By installing these traveling wheels on the two rails 8 so as to be movable, the laser ion source 2 is configured to be able to travel along the two rails 8. These two rails 8 are provided so as to be parallel to the ion beam 6 extracted from the laser ion source 2. In this case, a plurality of traveling wheels that travel on the two rails 8 may be directly attached to the bottom surface of the laser ion source 2.

  One end of a drive shaft 9 is attached to the pedestal of the laser ion source 2. For example, a ball screw shaft is used as the drive shaft 9. A shaft drive mechanism 9 a is attached to the other end of the drive shaft 9. For example, a stepping motor or a servo motor is used for the shaft drive mechanism 9a.

  Therefore, it is possible to move the laser ion source 2 along the two rails 8 by driving the shaft drive mechanism 9 a and rotating the drive shaft 9. In this case, the drive shaft 9 and the shaft drive mechanism 9a may be directly attached to the bottom of the laser ion source 2.

  Next, the operation of this embodiment will be described.

  When installing the laser ion source 2 and the RFQ 5, it is necessary to install the laser focus on the target 2 a and the axis of the ion beam 6.

  The axis of the ion beam 6 in the height direction is adjusted by installing both the laser ion source 2 and the RFQ 5 on a frame having the same height.

  When the ion beam 6 is directly incident on the RFQ 5 from the transport tube 2c, it is necessary to adjust the beam size and convergence. In this embodiment, the axial position of the ion beam 6 of the laser ion source 2 and the RFQ 5 is adjusted without releasing the vacuum state by connecting the bellows 3 to the connecting portion 2d between the laser ion source 2 and the RFQ 5. It becomes possible to do. That is, in the present embodiment, the axial positions of the transport tube 2c and the ion beam 6 of the RFQ 5 can be adjusted by expanding and contracting the bellows 3.

  In general, the target 2a, the laser ablation plasma 2b, and the transport tube 2c are applied with a high positive voltage with respect to RFQ5, and ions are accelerated and extracted using the potential difference from RFQ5. In this case, there are a method of applying a high voltage to the entire vacuum vessel 20 and a method of providing a separate chamber in which the target 2 a is built in the vacuum vessel 20 and applying this separate chamber to a high voltage. The present embodiment uses the former high voltage application method.

  Therefore, in the present embodiment, by connecting the insulating tube 4 in series to the connection portion 2d between the laser ion source 2 and the RFQ 5, the RFQ 5 and the laser ion source 2 are electrically separated, and the vacuum state is released. It is possible to adjust the position of the transport pipe 2c with respect to RFQ5 without any problem. The laser ion source 2 is installed on a gantry 7 having an insulating portion 10 attached to the bottom surface, and the insulating state is maintained.

  The laser ion source 2 needs to be placed in alignment with the axis of the ion beam 6 even after movement. Therefore, in this embodiment, the two rails 8 are provided on the gantry 7 as described above, and the laser ion source 2 is placed on a pedestal that travels on these rails 8, so that the axial direction of the ion beam 6 is increased. It is possible to move along.

  The laser ion source 2 can move along the two rails 8 by driving the shaft drive mechanism 9 a and rotating the drive shaft 9. When a stepping motor is used as the shaft drive mechanism 9a, the position of the laser ion source 2 can be finely adjusted and the reproducibility of the position of the laser ion source 2 can be improved. Further, when a motor such as a stepping motor is used for the shaft drive mechanism 9a, the drive control can be performed remotely.

  In this embodiment, the laser ion source 2 is moved using the drive shaft 9, but a linear movement mechanism that can withstand the load of the laser ion source 2, such as a jack or an air cylinder, is used. It may be. As a means for rotating the drive shaft 9, a manual rotation handle may be attached to the drive shaft 9.

  As described above, according to the present embodiment, the bellows 3 is provided in the connecting portion 2d, and the bellows 3 is expanded and contracted so that the laser ion source 2 can be moved along the axial direction of the ion beam 6. This makes it possible to adjust the position of the transport pipe 2c with respect to the RFQ 5 without releasing the vacuum state. As a result, the beam size and convergence when the ion beam 6 is incident on the RFQ 5 can be finely adjusted.

  Therefore, according to the present embodiment, even when there is a change in the extraction current value or valence ratio extracted from the laser ion source 2, it can be incident so as to match the acceptance of RFQ5. Therefore, a necessary number of ions can be transported without reducing the number of ions that can be accelerated by RFQ5.

(Second Embodiment)
FIG. 4 is a schematic cross-sectional view showing a second embodiment of the ion accelerator according to the present invention. FIG. 5 is a schematic sectional elevation view of FIG. The present embodiment is a modification of the first embodiment, and the same or corresponding parts as those of the first embodiment are denoted by the same reference numerals and redundant description is omitted.

  As shown in FIGS. 4 and 5, in this embodiment, side guide plates 11 are installed on both sides of the gantry 7 so as to be parallel to the axis of the ion beam 6 drawn from the laser ion source 2. These side guide plates 11 are installed such that the side surfaces of the pedestal on which the laser ion source 2 is placed are in contact with each other.

  Therefore, according to the present embodiment, when the pedestal on which the laser ion source 2 is placed is moved along the rail 8, it is guided and moved by the side guide plate 11, so that the movement of the laser ion source 2 can be performed without rattling. Can be ensured. As a result, the laser ion source 2 can be accurately moved along the axis of the ion beam 6. Therefore, the position of the transport pipe 2c with respect to RFQ5 can be adjusted accurately.

  In this embodiment, the example in which the side guide plates 11 are installed on both sides of the gantry 7 is described. However, the present invention is not limited thereto, and the pedestal on which the laser ion source 2 is placed by installing the side guide plates 11 on the floor surface. You may make it guide movement. In this case, it is necessary to increase the height of the side guide plate 11 by the height of the gantry 7.

(Third embodiment)
FIG. 6 is a schematic plan sectional view showing a third embodiment of the ion accelerator according to the present invention. FIG. 7 is a schematic sectional elevation view of FIG. FIG. 8 is a flowchart showing the operation of the control unit of FIG. The present embodiment is a modification of the first embodiment, and the same or corresponding parts as those of the first embodiment are denoted by the same reference numerals and redundant description is omitted.

  As shown in FIG.6 and FIG.7, this embodiment is installed in the state in which the distance meter 13a was fixed to the position where the mount frame 7 exists. The distance meter 13a measures the distance along the axial direction of the ion beam 6 of the laser ion source 2. The distance meter 13a may be, for example, a laser distance meter, or a light, ultrasonic wave, contact type position sensor, or the like. In the present embodiment, by installing the distance meter 13a, the moving distance along the axial direction of the ion beam 6 of the laser ion source 2 can be accurately measured.

  The laser ion source 2 is installed on a movable pedestal 12 formed in a rectangular plate. The movable pedestal 12 is provided with push screws 12a at two places on each side, for a total of four places. By changing the screwing depth of these push screws 12a, the position can be adjusted in a direction orthogonal to the axial direction of the ion beam 6 of the laser ion source 2. Although not shown, a drive motor that rotationally drives each push screw 12a is attached to the plurality of push screws 12a.

  The movable pedestal 12 is provided with position sensors 13b at two places on each side, for a total of four places. These position sensors 13b measure the position in the direction orthogonal to the axial direction of the ion beam 6 of the laser ion source 2. For example, the position sensor 13b may be a laser, an optical sensor, or a sensor using ultrasonic waves.

  The control unit 23 includes distance data along the axial direction of the ion beam 6 of the laser ion source 2 measured by the distance meter 13a and the axis of the ion beam 6 of the laser ion source 2 measured by the plurality of position sensors 13b. Position data in a direction orthogonal to the direction is input.

  The control unit 23 drives and controls the shaft drive mechanism 9a based on the distance data which is the measurement result of the distance meter 13a, and controls the distance along the axial direction of the ion beam 6 of the laser ion source 2 with respect to the RFQ 5, and this embodiment The first control unit of the form is configured. Further, the control unit 23 drives and controls the drive motor based on the position data as the measurement results of the plurality of position sensors 13b, and controls the position in the direction orthogonal to the axial direction of the ion beam 6 of the laser ion source 2 with respect to the RFQ 5. And the 2nd control part of this embodiment is also comprised.

  The distance data by the distance meter 13a and the position data by the position sensor 13b are output to the output unit 24. The output unit 24 displays an image of the distance and position of the laser ion source 2 based on the distance data and position data.

  The input unit 21 outputs drive signals to the shaft drive mechanism 9a and the drive motor that rotationally drives the push screw 12a via the control unit 23, respectively.

  In this embodiment, the example in which the distance meter 13a is installed on the gantry 7 has been described. However, the distance meter 13a may be installed on, for example, a floor surface or a wall surface.

  Next, operation | movement of the control part 23 of this embodiment is demonstrated according to the flowchart of FIG. FIG. 8 illustrates a case where the position of the laser ion source 2 with respect to the RFQ 5 is adjusted to finely adjust the beam size and convergence of the ion beam 6.

  First, when a drive signal is input from the input unit 21 to the shaft drive mechanism 9a, the shaft drive mechanism 9a is driven to move along the axial direction of the ion beam 6 of the laser ion source 2 (step S1).

  Next, the distance along the axial direction of the ion beam 6 of the laser ion source 2 is measured by the distance meter 13a (step S2). In step S3, it is determined whether or not the distance along the axial direction of the ion beam 6 of the laser ion source 2 is a desired distance, and steps S1 and S2 are repeated until the desired distance is reached. In (Step S3: Yes), the process proceeds to the next Step S4.

  In step S4, when a drive signal is input from the input unit 21 to the drive motor, the drive motor is driven to rotate the push screw 12a, and the laser ion source 2 is moved in a direction orthogonal to the axial direction of the ion beam 6. .

  Next, a position orthogonal to the axial direction of the ion beam 6 of the laser ion source 2 is measured by the position sensor 13b (step S5). In step S6, it is determined whether or not the position in the direction orthogonal to the axial direction of the ion beam 6 of the laser ion source 2 is a desired position, and steps S4 and S5 are repeated until the desired position is reached. In the case (step S6: Yes), the series of processes is finished.

  As described above, according to the present embodiment, the distance along the axial direction of the ion beam 6 of the laser ion source 2 with respect to the RFQ 5 is adjusted, and in the direction orthogonal to the axial direction of the ion beam 6 of the laser ion source 2 with respect to the RFQ 5. By adjusting the position, it is possible to adjust the position of the laser ion source 2 with respect to the RFQ 5 without releasing the vacuum state. That is, the position of the transport pipe 2c with respect to the RFQ 5 can be adjusted. As a result, the beam size and convergence when the ion beam 6 is incident on the RFQ 5 can be finely adjusted, and reproducibility can be ensured.

(Other embodiments)
Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, changes, and combinations can be made without departing from the scope of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

  In addition, although each said embodiment demonstrated the example applied to the heavy particle beam therapy apparatus, it is applicable not only to this but the particle beam therapy apparatus using a proton beam, for example.

  DESCRIPTION OF SYMBOLS 1 ... Laser beam, 1a ... Laser transmitter, 1b ... Laser power source, 2 ... Laser ion source, 2a ... Target, 2b ... Laser ablation plasma, 2c ... Transport pipe, 2d ... Connection part, 3 ... Bellows (expandable part), 3b ... connecting portion, 4 ... insulating tube, 5 ... RFQ (linear accelerator), 5a ... RFQ electrode, 5b ... RFQ end plate, 6 ... ion beam, 7 ... mounting frame, 8 ... rail, 9 ... drive shaft, 9a ... shaft Drive mechanism, 10 ... insulating part, 11 ... side guide, 12 ... movable pedestal, 12a ... push screw, 13 ... DTL (linear accelerator), 13a ... distance meter, 13b ... position sensor, 20 ... vacuum vessel, 21 ... input part , 23 ... control unit (first control unit, second control unit), 24 ... output unit

Claims (10)

A laser ion source for extracting an ion beam from plasma generated by irradiating laser light;
A linear accelerator for accelerating an ion beam extracted from the laser ion source;
A connection for connecting the laser ion source and the linear accelerator while maintaining a vacuum;
A transport tube having one side fixed to the laser ion source and the other side extending through the connection to the linear accelerator and transporting an ion beam extracted from the laser ion source to the linear accelerator;
An extendable part provided in the connection part and capable of extending and contracting in the axial direction of the connection part;
With
Ion acceleration characterized in that the laser ion source is movable along the axial direction of the ion beam, and a distance meter is provided for measuring a moving distance of the laser ion source along the axial direction of the ion beam. apparatus.   The ion accelerator according to claim 1, wherein the laser ion source is installed on a gantry, the gantry is supported by an insulating portion, and an insulating tube is connected to the connecting portion.   The ion accelerator according to claim 2, wherein a rail is laid on the mount, and the laser ion source is movable along the rail. The ion according to claim 3 , wherein a drive shaft for moving the laser ion source along the rail and a shaft drive mechanism for driving the drive shaft are attached to the laser ion source. Accelerator.   5. The ion accelerator according to claim 1, further comprising a guide plate that guides movement of the laser ion source along an axial direction of the ion beam. A first control unit is provided that drives and controls the shaft driving mechanism based on a measurement result of the distance meter and controls a distance along the axial direction of the ion beam of the laser ion source with respect to the linear accelerator. The ion accelerator according to claim 4 . The ion acceleration according to any one of claims 1 to 6, wherein a plurality of push screws for adjusting the position of the laser ion source in a direction orthogonal to a moving direction along the axial direction of the ion beam are provided. apparatus. The ion acceleration according to claim 1 , further comprising a position sensor that measures a position of the laser ion source in a direction orthogonal to a moving direction along an axial direction of the ion beam. apparatus. A second control unit configured to drive and control a drive motor based on a measurement result of the position sensor and to control a position of the laser ion source in a direction orthogonal to a moving direction along an axial direction of the ion beam with respect to the linear accelerator; The ion accelerator according to claim 8 , wherein the ion accelerator is provided.   A laser ion source for extracting an ion beam from plasma generated by irradiating laser light;
  A linear accelerator for accelerating an ion beam extracted from the laser ion source;
  A connection for connecting the laser ion source and the linear accelerator while maintaining a vacuum;
  A transport tube having one side fixed to the laser ion source and the other side extending through the connection to the linear accelerator and transporting an ion beam extracted from the laser ion source to the linear accelerator;
  An extendable part provided in the connection part and capable of extending and contracting in the axial direction of the connection part;
  A synchrotron that transports the ion beam of the linear accelerator and circulates the ion beam to accelerate to a predetermined energy;
  An extraction device for extracting an ion beam accelerated by the synchrotron;
  An irradiation device for irradiating an irradiation target with an ion beam extracted by the extraction device;
  A particle beam therapy characterized in that the laser ion source is movable along the axial direction of the ion beam, and a distance meter is provided for measuring a moving distance of the laser ion source along the axial direction of the ion beam. apparatus.

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