JPH11233300A - Particle accelerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a particle accelerator capable of suppressing the dispersion of the dose and the time fluctuation of charged particle beams. SOLUTION: Charged particles produced by an ion source 1 in a charged particle producing facility are accelerated up to a predetermined energy level by an incident accelerator 2 and further accelerated up to an energy level irradiated on an object 6 by a main accelerator 3, and the accelerated charged particles are transported to the object by a beam transportation system 4. The charged particles from the beam transportation system 4 of the charged particle producing facility are incident in a beam radiation system 5 and are radiated on the object. In this case, an accelerator control circuit 8 controls the charged particle producing facility such that the irradiation dose of the charged particle beams irradiated on the object 6 coincides with a reference value based on the control command from a dose control circuit 10 and stops the irradiation of the charged particle beams on the object 6 when the accumulated value of the irradiation dose of the charged particle beams irradiated on the object 6 reaches a predetermined quantity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a particle accelerator for accelerating and emitting charged particles, transporting the charged particles, and irradiating an object.

[0002]

2. Description of the Related Art Charged particles accelerated by a particle accelerator are used for radiotherapy and various experiments. FIG. 3 is a configuration diagram of a conventional particle accelerator. In the particle accelerator, first, charged particles are generated by the ion source 1, and the generated charged particles are accelerated by the incidence accelerator 2 to a predetermined energy. The main accelerator 3 further accelerates the energy to irradiate the object, and the accelerated charged particles are transported to the object by the beam transport system 4. Hereinafter, a process from the generation of charged particles by the ion source to the transport of the charged particles to the target by the beam transport system is referred to as a charged particle generation facility.

[0003] Here, an ion source 1 constituting a charged particle generation facility is a device that generates charged particles such as protons, heavy ions, carbon ions, silicon ions, etc., and an injection accelerator 2
Is an accelerator such as a linear accelerator that accelerates charged particles from an ion source to an energy (several MeV or more) that can be accelerated by the main accelerator. The main accelerator 3 is an accelerator such as a synchrotron for accelerating to the energy used for treatment or experiment, and the beam transport system 4 is a beam irradiation system for treating the charged particles emitted from the main accelerator 3 in a treatment room or a laboratory. It is a system for transporting up to 5.

[0004] Charged particles from a beam transport system 4 of the charged particle generation equipment are input to a beam irradiation system 5 and irradiated on an object 6. The beam irradiation system 5 that takes over the charged particle beam from the beam transport system 4 has a dose monitor 7 that measures the charged particle beam. The charged particle beam measured by the dose monitor is input to an accelerator control circuit 8. It has become so.

[0005] In controlling the irradiation dose of the charged particle beam in the accelerator control circuit 8, the dose of each charged particle beam pulse is measured by the dose monitor 7, and when the integrated value reaches a specified value, the beam shutter 9 is controlled. Is closed to stop the passage of the charged particle beam to the object 6.

[0006]

However, the variation in the dose of each pulse of the charged particle beam depends on the ripple and the stability of each device in the charged particle generator of the particle accelerator. It is not performed from the beam irradiation system 5 which is the last stage.

As described above, in the conventional particle accelerator, since control for suppressing the variation and the time variation of each charged particle beam is not performed, the time variation of the charged particle generation equipment in the particle accelerator is not considered. Accordingly, the dose of the charged particle beam fluctuates. In order to reduce the fluctuation of the charged particle beam and perform stable treatments and experiments, it is necessary to change the operation parameters by the operator, which places a heavy burden on the operator.

An object of the present invention is to provide a particle accelerator capable of suppressing variation in dose of a charged particle beam and time variation.

[0009]

According to a first aspect of the present invention, there is provided a particle accelerator, in which a charged particle generated by an ion source is accelerated to a predetermined energy by an accelerator for incidence, and further increased to an energy for irradiating an object with a main accelerator. A charged particle generation facility that accelerates and transports the accelerated charged particles to the target using a beam transport system, a beam irradiation system that irradiates the target with charged particles from the beam transport system of the charged particle generation facility, and irradiates the target A dose control circuit that outputs a control command for adjusting the dose of the charged particle beam so that the dose of the charged particle beam to be irradiated becomes a preset reference value, and based on the control command from the dose control circuit. Controls the charged particle generation equipment so that the dose of the charged particle beam irradiated to the target becomes the reference value, and integrates the dose of the charged particle beam irradiated to the target Characterized by comprising a accelerator control circuit for stopping the irradiation of the charged particle beam to the object when a predetermined amount.

In the particle accelerator according to the first aspect of the present invention,
The charged particle generation equipment accelerates the charged particles generated by the ion source to a predetermined energy with the accelerator for injection, further accelerates with the main accelerator to the energy to irradiate the target object, and transmits the accelerated charged particles to the target object. Transport by Charged particles from the beam transport system of the charged particle generation equipment are incident on a beam irradiation system and are irradiated on an object. In this case, the accelerator control circuit controls the charged particle generation equipment based on the control command from the dose control circuit so that the irradiation dose of the charged particle beam applied to the object becomes a reference value, and irradiates the object. When the integrated value of the irradiated dose of the charged particle beam reaches a predetermined amount, the irradiation of the charged particle beam to the object is stopped.

A particle accelerator according to a second aspect of the present invention is the particle accelerator according to the first aspect, wherein the dose control circuit calculates a change in the irradiation dose of the charged particle beam irradiated to the object, and calculates the change in the change. And outputting a control command for adjusting the irradiation dose of the charged particle beam so that the irradiation dose of the charged particle beam becomes a preset reference value.

In the particle accelerator according to the second aspect of the present invention,
In addition to the operation of the particle accelerator according to claim 1, the irradiation dose of the charged particle beam is set to a reference value set in advance based on a change in the irradiation dose of the charged particle beam applied to the object. Adjust the dose of the charged particle beam.

A particle accelerator according to a third aspect of the present invention is the particle accelerator according to the first or second aspect, wherein the irradiation dose of the charged particle beam used in the dose control circuit and the accelerator control circuit is provided in a beam irradiation system. And using a measurement value measured by the same dose monitor.

In the particle accelerator according to the third aspect of the present invention,
In addition to the operation of the particle accelerator according to claim 1 or 2, the dose control circuit and the accelerator control circuit use the irradiation dose of the charged particle beam measured by the dose monitor provided in the beam irradiation system.

According to a fourth aspect of the present invention, in the particle accelerator according to the first or second aspect, the irradiation dose of the charged particle beam used in the dose control circuit is controlled by a dose monitor provided in a beam transport system. The measured value is used, and the irradiation amount of the charged particle beam used in the acceleration control circuit uses a value measured by a dose monitor provided in the beam irradiation system.

A particle accelerator according to a fourth aspect of the present invention is the particle accelerator according to the first or second aspect, wherein the dose control circuit uses an irradiation dose measured by a dose monitor provided in the beam transport system, and controls the accelerator. The circuit uses the irradiation dose measured by the dose monitor provided in the beam irradiation system.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of a particle accelerator according to the first embodiment of the present invention. The first embodiment is different from the conventional example shown in FIG. 1 in that the irradiation amount of the charged particle beam is adjusted so that the irradiation dose of the charged particle beam applied to the object 6 becomes a preset reference value. A dose control circuit 10 for outputting a control command for adjustment is provided, and the accelerator control circuit 8 sets the irradiation dose of the charged particle beam applied to the object 6 based on the control command from the dose control circuit 10 to a reference value. And controlling the charged particle generation equipment so that the irradiation of the charged particle beam to the object 6 is stopped when the integrated value of the irradiation dose of the charged particle beam applied to the object 6 reaches a predetermined amount. It is.

The charged particle generating equipment for obtaining a charged particle beam includes an ion source 1 for generating charged particles, an accelerator 2 for accelerating the charged particles to an energy that can be accelerated by the main accelerator 3, and an accelerator 2 for incidence. Main accelerator 3 that accelerates the charged particles to the level of energy to irradiate the target object
And a beam transport system 4 for transporting the charged particle beam accelerated by the main accelerator 3 to a beam irradiation system 5.

That is, the charged particles are generated in the ion source 1, accelerated to an energy of several MeV by an injection accelerator 2 such as a linear accelerator, and further accelerated in a main accelerator 3 such as a synchrotron or a cyclotron to be transported. 4 is emitted. Then, the light reaches the beam irradiation system 5 through the beam transport system 4.

In the beam irradiation system 5, the shape of the charged particle beam is shaped in accordance with the shape of the treatment section to be irradiated or the shape of the experimental object. The dose monitor 7 detects the dose of the charged particle beam applied to the object 6, and controls the accelerator control circuit 8.
And input to the dose control circuit 10. As the dose monitor 7, a monitor such as a parallel plate ionization chamber is used.

The dose control circuit 10 receives dose data of each pulse measured by the dose monitor 7 provided in the beam irradiation system 5 and compares the input pulse dose with a preset reference value. I do. In other words, the deviation between the two signals is calculated, and the accelerator control circuit 8 is controlled so as to finely adjust the parameters of the next and subsequent pulse operations to increase or decrease the beam current value of the charged particles. The increase / decrease of the beam current value of the charged particles can be controlled by the accelerator control circuit 8 by adjusting the amount of charged particles generated in the ion source 1 or by changing the incidence of the incident accelerator 2.
The adjustment is performed by adjusting the acceleration voltage of the main accelerator 3, the acceleration voltage of the main accelerator 3, and the like, or by adjusting the transport voltage of the beam transport system 4.

As described above, the dose control circuit 10 performs processing for comparing the dose data obtained by the dose monitor 7 of the beam irradiation system 5 with the reference value of the dose.
Then, the heater current of the ion source 1 is increased / decreased, the high-frequency acceleration voltage of the injection accelerator 2 is increased / decreased, and the main accelerator 3 is increased.
Control of the high-frequency acceleration voltage of the device. Further, the accelerator control circuit 8 counts the dose data obtained by the dose monitor 7 of the beam irradiation system 5, and when the integrated value reaches a specified amount, closes the beam shutter 9 and stops beam irradiation. Thereby, the irradiation dose to the object 6 is controlled.

Therefore, according to the first embodiment,
If the charged particle beam has a variation or a time variation and a deviation from the reference value occurs, the charged particle beam can be corrected within the next pulse or several pulses to suppress the variation or the time variation of the charged particle beam.

Next, a second embodiment of the present invention will be described. FIG. 2 is a configuration diagram of a particle accelerator according to a second embodiment of the present invention. In the second embodiment, a dose monitor 11 is additionally provided in the beam transport system 4, and the dose of the charged particle beam used for controlling the increase / decrease of the current value of the charged particle beam in the dose control circuit 10 is determined by the dose sensor 11. This is to be detected by.

A dose monitor 11 is additionally provided to the beam transport system 4, and the dose of the charged particle beam measured by the dose monitor 11 is input to the dose control circuit 10, and the variation and fluctuation of the dose of the charged particle beam are monitored. Used for control to suppress. In this case, the accelerator control circuit 8 integrates the dose of the charged particle beam obtained by the dose monitor 7 of the beam irradiation system 5, and when the integrated value reaches a specified value, the beam shutter 9
Close.

As described above, it is necessary to provide the dose monitor 11 separately from the dose monitor 7, but the dose monitor 11 of the beam transport system 4 is provided with the beam shutter 9 of the beam irradiation system 5.
Since it can be arranged further upstream, there is an advantage that the increase / decrease control of the current value of the charged particle beam can be performed even when the beam shutter 9 is closed.

In the above description, the dose control circuit 10 compares the dose of the charged particle beam with a preset reference value, and controls the increase or decrease of the current value of the charged particle beam based on the deviation. Monitors the temporal variation of the dose of the pulse input from the cotton amount monitor 7, determines the change in the dose of the charged particle beam, and based on the change in the dose of the charged particle beam, It is also possible to control the increase and decrease of the current value. That is, it is determined whether the dose of the charged particle beam tends to increase or decrease, and based on the result, the increase / decrease control of the current value of the charged particle beam is performed.

As described above, it is determined whether or not the difference in irradiation dose from the start of operation or from the start of irradiation is likely to exceed the reference value if the operation is continued, and if the difference is likely to exceed, the accelerator control circuit 8 Then, the parameters of the pulse operation after the next time are finely adjusted to control the beam current value of the charged particles to decrease or increase.

Thus, in the case where the charged particle beam has variation or time variation, the operation of the particle accelerator can be performed while keeping the difference in the irradiation dose from the start of operation or from the start of irradiation small.

[0030]

As described above, according to the present invention, it is possible to reduce the variation in dose and time variation due to the charged particle beam without the intervention of an operator, and to achieve higher quality charging in treatment and irradiation experiments. A supply of a particle beam can be provided.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a particle accelerator according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a particle accelerator according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a conventional particle accelerator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ion source 2 Injection accelerator 3 Main accelerator 4 Beam transport system 5 Beam irradiation system 6 Target 7 Dose monitor 8 Accelerator control circuit 9 Beam shutter 10 Dose control circuit 11 Dose monitor

Claims (4)

[Claims] A charged particle generated by an ion source is accelerated to a predetermined energy by an injection accelerator and further accelerated by a main accelerator to energy for irradiating an object, and the accelerated charged particles are transported to the object by a beam transport system. Charged particle generation equipment to transport in, a beam irradiation system to irradiate the target object with charged particles from the beam transport system of the charged particle generation equipment,
A dose control circuit that outputs a control command for adjusting a dose of the charged particle beam so that a dose of the charged particle beam irradiated to the object is a preset reference value, and the dose control circuit. And controlling the charged particle generation equipment so that the irradiation dose of the charged particle beam applied to the object based on the control command from the reference value becomes the reference value, and the irradiation dose of the charged particle beam applied to the object. And an accelerator control circuit for stopping the irradiation of the charged particle beam to the object when the integrated value of (a) becomes a predetermined amount. 2. The particle accelerator according to claim 1, wherein the dose control circuit calculates a change in an irradiation dose of the charged particle beam applied to the object, and precedes the change based on the change. A particle accelerator characterized by outputting a control command for adjusting the dose of a charged particle beam so that the dose of the charged particle beam becomes a preset reference value. 3. The particle accelerator according to claim 1, wherein the dose of the charged particle beam used in the dose control circuit and the accelerator control circuit is determined by the same dose monitor provided in the beam irradiation system. A particle accelerator characterized by using measured values. 4. The particle accelerator according to claim 1, wherein the irradiation dose of the charged particle beam used in the dose control circuit is a measured value measured by a dose monitor provided in the beam transport system. The particle accelerator according to claim 1, wherein the irradiation amount of the charged particle beam used in the acceleration control circuit uses a measurement value measured by a dose monitor provided in the beam irradiation system.