JP3833390B2 - Particle accelerator timing controller - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a timing control device that controls the operation timing of a control target device that needs to operate with high speed, high accuracy, and high reproducibility of a particle accelerator that accelerates charged particles such as ions.
[0002]
[Prior art]
FIG. 18 schematically shows a configuration example of this type of particle accelerator. In this figure, charged particles such as ions are output from the injector 1 with a constant energy, and are guided to the acceleration ring 5 through the low energy particle transport system 3. Ions guided to the acceleration ring 5 are accelerated by the acceleration cavity 7. While being accelerated, the ions are pulled toward the center of the acceleration ring 5 by the magnetic field generated by the plurality of opposingly arranged deflecting electromagnets 9 and continue to circulate in the acceleration ring 5. When ions reach a certain energy level as a result of the acceleration, the ions are moved from the acceleration ring 5 to the high energy particle transport system 13 by the ejector 11 and guided to the utilization system 17 through the extraction system magnet 15. In the utilization system 17, accelerated charged particles (ions) are used for cancer treatment or the like.
[0003]
  The timing controller outputs an operation trigger at a predetermined timing to the injector 1, the emitter 11, and the acceleration pattern controller of the accelerating cavity 7, and the ions are efficiently low-energy particle transport system 3, acceleration ring 5, and It is intended to be guided to the utilization system 17 through the high energy particle transport system 13. if,If the timing control device does not operate reasonably, a defect such as disappearance occurs because ions collide with the inner wall of the acceleration ring 5 before being guided to the utilization system 17.
[0004]
The conventional particle accelerator timing control apparatus also performs timing control of the magnetic field strength of the deflecting electromagnet 9 in synchronization with the timing control of the acceleration pattern control of the injector 1, the emitter 11, and the acceleration cavity 7.
[0005]
FIG. 19 shows a timing chart of timing control of a conventional particle accelerator timing control device. In FIG. 19, after ions are incident on the acceleration ring 5 from the injector 1, acceleration by the acceleration cavity 7 is started, and the strength of the deflecting electromagnet 9 starts to increase in synchronization with the acceleration. After that, when ions reach a certain predetermined energy level, the emitter 11 is triggered to reset the acceleration level of the acceleration cavity 7 to the original incident level, and the intensity of the deflecting electromagnet 9 is also synchronized with it. Returning to the original level, we prepared for the next incident-acceleration-exit timing control.
[0006]
[Problems to be solved by the invention]
By the way, a resonance power supply may be used as a power supply for the deflection electromagnet 9. Resonance power supplies have the advantage of being small and inexpensive compared to conventional electromagnet power supplies. The current value of the resonant power supply changes in a sine wave shape of about 20 Hz, and accordingly, the magnetic field generated by the deflection electromagnet 9 also changes in a sine wave shape of about 20 Hz. At this time, it is impossible to control the operation timing of the deflection electromagnet by the timing control device, and it is rather necessary to follow the operation of the deflection electromagnet in order to perform rational timing control.
[0007]
  Therefore, when a resonant power source is used as the power source for the deflection electromagnet 9, the conventional timing control method uses a resonant power source.SourceSince the incident-acceleration-exit timing control is performed asynchronously with the magnetic field to be generated, there arises a problem that the efficiency becomes very low due to particles colliding with the inner wall of the acceleration ring 5 and disappearing.
[0008]
The present invention has been made in view of such a point, and an object of the present invention is to provide a timing control device capable of performing rational timing control on a control target device of a particle accelerator using a resonance power source. And
[0011]
[Means for Solving the Problems]
  That is, according to the first aspect of the present invention, an injector for entering charged particles into the acceleration ring, acceleration means for accelerating the incident charged particles to a predetermined energy, and circulating the charged particles in the acceleration ring. Of a particle accelerator for controlling the operation timing of each device related to the incidence, acceleration, and emission of a particle accelerator comprising a deflection electromagnet that deflects the particle and an ejector that ejects the accelerated charged particles from the acceleration ring to the utilization system In the timing control device, the deflection electromagnet is supplied with a current that changes sinusoidally from an electromagnet power source, and forms a magnetic field in which the magnetic flux density changes sinusoidally in response to the change in the current. A sine wave signal detecting means for detecting a sine wave signal corresponding to a change in the magnetic field of the sine wave signal; A cycle signal output means for outputting a pulse signal in the form of a pulse and a reference clock in which a pulse appears at a rate of one pulse when the magnetic flux density is increased by a certain amount are input to synchronize with the cycle signal. , A trigger signal output means for outputting a trigger signal of each device relating to the incidence, acceleration and emission in accordance with a preset count value based on the synchronization clock, and use of the utilization system And setting count value changing means for changing the emission count value set in the trigger signal output means. ThisIn this invention, the incident-acceleration-exit timing control can be performed in synchronization with the change of the magnetic field of the deflection electromagnet.Further, the energy of the emitted charged particles can be changed according to the application of the utilization system.
[0014]
  Claim2The invention of claim1The timing control apparatus according to claim 1, further comprising cycle suppression means for suppressing the number of cycle signals output from the cycle signal output means to a predetermined number of cycles according to the use of the utilization system.
[0015]
  Claim2In this invention, the quantity of the charged particles to be emitted can be changed according to the usage of the utilization system.
[0016]
  Claim3The invention of claim1 or 2In the timing control device, a beam amount setting value file for storing in advance a pattern of a combination of the number of cycle signals output from the cycle signal output means and the emission count value set in the trigger signal output means, and the beam amount A beam amount control unit that selects a pattern of the combination according to a use of the utilization system based on a setting value file and controls the amount and energy of charged particles emitted to the utilization system. And
[0017]
  Claim3In this invention, by preparing in advance a pattern of the combination of the number of cycle signals and the count value for emission according to the application of the utilization system, the amount and energy of charged particles emitted can be easily controlled according to the application. can do.
[0018]
  Claim4The invention of claim3In the timing control device, for each emission target of the utilization system, according to the emission target file in which the operation plan information designating the combination pattern is registered, and the operation plan information of the emission target specified in the emission target file And an operation plan control means for providing the beam amount control means with information for selecting the combination pattern.
[0019]
  Claim4In this invention, for each emission target, a pattern that defines the amount and energy of the charged particles to be emitted is registered in advance as operation plan information. It is also possible to easily emit light by changing the angle.
[0020]
  Claim5The invention of claim1 to 46. The timing control device according to claim 1, wherein the cycle signal output means inputs the sine wave signal, and outputs a pulsed cycle signal when the sine wave signal falls below a threshold value. And a cycle signal delay means for delaying the cycle signal from the cycle signal generating means and outputting the delayed signal at an optimum value near the lowest value of the sinusoidal signal.
[0021]
  Claim5In this invention, charged particles can be incident at an optimum timing when the intensity of the magnetic field of the deflection electromagnet is near the minimum value.
[0022]
  Claim6The invention of claim1 to 5In the timing control device according to any one of the above, permission signal generating means for monitoring the position of the irradiation target portion that fluctuates at a substantially constant rhythm, and generating a permission signal when the irradiation target portion is at a predetermined irradiation position; Cycle permission means for permitting the output of the cycle signal from the cycle signal output means only while the permission signal is generated.
[0023]
  Claim6In this invention, even if the irradiation target site fluctuates due to heartbeat or respiration of the heart, lungs, and the vicinity thereof, the necessary charged particle beam is irradiated to the irradiation target site accurately in synchronization with the heartbeat or respiration. be able to.
[0024]
  Claim7The invention of claim6The timing control device according to claim 1, further comprising an emitter synchronizing means for transmitting a trigger signal for emission from the trigger signal output means to the emitter only while the permission signal is generated.
[0025]
  Claim7In this invention, even when the irradiation target site is deviated from the irradiation position at the time of emission, it is possible to effectively prevent emission of charged particles and irradiation to other sites.
[0026]
  Claim8The invention of claim1 to 7In the timing control device according to any one of the above, the intensity of the magnetic field of the output system magnet for guiding charged particles from the output device to the utilization system according to the output count value set in the trigger signal output means And an output magnet control means for controlling the power supply of the output system magnet.
[0027]
  Claim8In this invention, the magnetic field of the outgoing magnet can be optimally adjusted according to the outgoing energy of the charged particles.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0029]
In FIG. 18, the operation of the particle accelerator using the resonance power source as the power source of the deflection electromagnet 9 needs to be based on the magnetic flux density generated by the resonance power source. In other words, the magnetic flux density changes to a sinusoidal wave of about 20 Hz, but the ions are incident on the acceleration ring 5 from the low energy particle transport system 3 at the timing when the magnetic flux density is near the minimum value, and the ions are accelerated before reaching the maximum value. However, it is necessary to control the timing such that the light is emitted from the acceleration ring 5 to the high energy particle transport system 13. Then, the incidence of the next period starts at the timing near the next lowest value of the 20 Hz sine wave. Therefore, the incident-acceleration-exit cycle is repeated at a period of about 20 Hz.
[0030]
The particle accelerator timing control apparatus according to the present invention is for rationally carrying out the above timing control.
[0031]
FIG. 1 shows a first embodiment of a timing controller for a particle accelerator according to the present invention. In this figure, the code | symbol 19 is a particle | grain accelerator and the control object apparatus 21, such as the emitter 11, the radiation | emission system magnet 15, and other injectors 1, is shown as a control object apparatus. The main part of the present embodiment is composed of a cycle signal generation means 23, a cycle signal delay means 25, a synchronization means 27, and a delay counter 29, each outputting a pulse according to the timing chart shown in FIG. .
[0032]
As shown in FIG. 2A, the cycle signal generating means 23 inputs a signal substantially proportional to the sinusoidal magnetic flux density of about 20 Hz created by the deflection electromagnet 9, and as shown in FIG. A pulse is output as a cycle signal near the lowest value of the signal.
[0033]
As shown in FIG. 2C, the cycle signal delay means 25 delays the cycle signal from the cycle signal generation means 23 by a predetermined time t1 to a position corresponding to the optimum value near the lowest value of the sine wave signal.
[0034]
The synchronizing means 27 inputs a reference clock pulse based on the change in the magnetic field of the deflecting electromagnet 9 as shown in FIG. 2D, and outputs a synchronized clock pulse synchronized with the output signal from the cycle signal delay means 25. Output as shown in FIG.
[0035]
As shown in FIG. 2 (f), the delay counter 29 counts the synchronization clock pulse from the synchronization means 27 for a set number of times, and outputs a trigger signal for the operation timing of the control target device. For example, the incident delay counter 29 outputs the initial pulse of the synchronous clock as a trigger signal of the injector 1, and the emission delay counter 29 outputs a pulse corresponding to the set emission count as a trigger signal of the emitter 11. To do.
[0036]
In the present embodiment, in addition to the main part, as a means for generating an input signal of the cycle signal generating means 23, either a current detecting means 31 or a magnetic flux density detecting means 33 can be selected, and the current detecting means 31 and A cycle signal delay adjusting means 35 for adjusting the delay set time t1 of the cycle signal delay means 25 according to which one of the magnetic flux density detection means 33 is selected is provided.
[0037]
Furthermore, in this embodiment, in order to satisfy the requirement of the utilization system 17 that it is desired to easily change the amount and energy of the ion beam according to the intended use, the set count value changing means 37, the cycle suppressing means 39, the beam amount control means. 41, a beam amount set value file 43, an operation plan control means 45, an emission target file 47, and an operation result record file 49.
[0038]
The set count value changing unit 37 changes the set count value of the delay counter 29 based on the emission count from the beam amount control unit 41. The cycle suppression unit 39 suppresses the number of output cycles of the cycle signal generation unit 23 based on the number of cycles from the beam amount control unit 41.
[0039]
The beam quantity control unit 41 obtains a pattern number that matches the beam quantity and energy level required by the utilization system 17 from the operation plan control unit 45 and refers to the beam quantity set value file 43 to determine the extraction count and the number of cycles. To do. The beam amount set value file 43 stores the number of cycles and the emission count for each pattern number in advance.
[0040]
The operation plan control unit 45 gives a pattern number corresponding to the beam amount and the energy level to the beam amount control unit 41 for each application based on the emission target file 47 and records it as an operation result in the operation result record file 49. The emission target file 47 stores a pattern number for each application in advance.
[0041]
Although beams of various energy levels pass through the high-energy particle transport system 13, in order for these beams to pass smoothly, it is necessary to adjust the magnetic field intensity of the extraction system magnet 15 according to the energy level of the beam. . In order to solve this problem, the present embodiment includes an output magnet control means 51 and an output magnet setting value file 53.
[0042]
The emission system magnet control means 51 calculates the magnetic field strength of the emission system magnet 15 based on the emission count from the set count value changing means 37 and sets it as the power source of the emission system magnet 15. Adjust the magnetic field strength. Here, the magnetic field strength of the output system magnet 15 can be easily obtained by using the output magnet setting file 53 that stores the magnetic field strength of the output system magnet 15 in advance for each output count.
[0043]
In the utilization system 17, the beam may be used for medical purposes in which the affected part of the cancer patient is irradiated and the cancer cells are destroyed. At this time, only the cancer cells must be irradiated with the beam. When cancer cells are present on an organ that is constantly moving, such as the lung or heart, it is necessary to irradiate the beam only when the cancer cells to be irradiated move on the irradiation target.
[0044]
In order to solve this, the present embodiment includes a cycle permission means 55 and an emitter synchronization means 57. In addition, the heartbeat signal generating means 59 and the respiration signal generating means 61 are installed so as to be switchable as generating the input signals of the cycle permission means 55 and the emitter synchronizing means 57.
[0045]
The cycle permission means 55 receives from the heartbeat signal generation means 59 or the respiration signal generation means 61 a permission signal that is turned on only when the cancer cell to be irradiated is on the irradiation target, and the cycle signal only when this signal is in the ON state. The generating means 23 is allowed to output a cycle signal.
[0046]
Similarly, the emitter synchronizing means 57 receives a permission signal and passes the trigger signal of the delay counter 29 for the emitter only when the permission signal is in the ON state.
[0047]
Next, the operation of the present embodiment will be described.
The cycle signal generating means 23 inputs a signal as shown in FIG. 2 (a), which is substantially proportional to the sinusoidal magnetic flux density of about 20 Hz produced by the deflection electromagnet 9 from the current detecting means 31 or the magnetic flux density detecting means 33, A pulse as shown in FIG. 2B is output as a cycle signal. This cycle signal indicates a period of incidence-acceleration-exit repeated at a period of about 20 Hz.
[0048]
FIG. 3 shows an example of the circuit configuration of the current detection means 31, and FIG. 4 shows the waveforms of the signals IA, V1B and V1C of the circuit shown in FIG. As shown in FIG. 3, the current detecting means 31 uses a coil 71 to detect a signal V1B proportional to the differential value of the current ΙA supplied from the deflecting electromagnet power supply 9a to the deflecting electromagnet 9, and sets the voltage follower 31a. To the integrator 31b. The output of the integrator 31b is K1 * IA, and the signal V1C finally output from the current detection means 31 is
V1C = K1 * IA + K2 * V1b
It becomes. Here, K1 and K2 are constants, V1b is a variable bias voltage, and the bias voltage V1b is added to the output of the integrator 31b so that the cycle signal generator 23 can appropriately process it.
[0049]
When noise is mixed in the current value supplied from the deflecting electromagnet power supply 9a to the deflecting electromagnet 9, a low-pass filter as shown in FIG. 5 is used for current value detection as the current value filter 73 shown in FIG. A configuration in which the coil 71 is inserted between the current value detecting means 31 and the coil 71 is also possible.
[0050]
FIG. 6 shows an example of the circuit configuration of the magnetic flux density detecting means 33, and FIG. 7 shows the waveforms of the respective signals BA, V2B and V2C of the circuit shown in FIG. As shown in FIG. 6, the magnetic flux density detecting means 33 uses a coil 75 to detect a signal V2B proportional to the differential value of the magnetic flux density BA of the magnetic field generated by the deflecting electromagnet 9, and an integrator 33b via the voltage follower 33a. To enter. The output of the integrator 33b is K3 * BA, and the final output V2C is
V2C = K3 * BA + K4 * Vb
It becomes. Here, K3 and K4 are constants, Vb is a variable bias voltage, and a bias voltage is applied to the output of the integrator 33b so that the cycle signal generating means 23 can appropriately process it.
[0051]
When noise is mixed in the magnetic flux density detection value of the magnetic field generated by the deflection electromagnet 9, a low-pass filter as shown in FIG. 5 is used as the magnetic flux density value filter 77, and the magnetic flux density value detection coil 75 and the magnetic flux density detection. It is possible to adopt a configuration in which it is inserted between the means 33.
[0052]
FIG. 8 shows a configuration example of the cycle signal generating means 23, and FIG. 9 shows a signal processing process in the cycle signal generating means 23. In FIG. 8, the cycle signal generating means 23 includes a comparator 23a and a mono multi 23b.
[0053]
The comparator 23a receives the reference voltage Vref and the output from the current value detecting means 31 or the magnetic flux density detecting means 33, that is, a signal Vc having a sine wave shape of approximately 20 Hz, and as shown in FIGS. 9 (a) and 9 (b), 20Hz. A pulse signal that is turned on only when the sine wave signal Vc is lower than the reference voltage Vref is output.
[0054]
As shown in FIG. 9C, the mono multi 23b aligns the pulse width of this pulse signal to a constant width and outputs it as a cycle signal. Note that a gate is inserted in the output stage of the mono-multi 23 b, and its opening / closing is controlled by the cycle suppressing means 39. Thereby, the cycle suppression means 39 can suppress the delay counter 29 from outputting a trigger signal.
[0055]
By the way, as shown in FIG. 9C, the cycle signal is output t2 seconds before the 20 Hz sine wave reaches its lowest value. In addition, there is a slight timing difference between the case where the cycle signal is generated from the detected value of the magnetic flux density and the case where the cycle signal is generated from the detected value of the power supply current of the deflection electromagnet 9. Cycle signal delay means 25 and cycle signal delay adjustment means 35 are provided in order to correct the timing deviation when the cycle signal and the 20 Hz sine wave become the minimum value and the timing deviation when the generation source of the cycle signal changes. Yes.
[0056]
That is, as shown in FIG. 2C, the cycle signal delay means 25 outputs a pulse after the time t1 seconds set by the cycle signal delay adjustment means 35 after inputting the cycle signal.
[0057]
The cycle signal delay adjusting means 35 stores in advance the set time when the cycle signal is generated from the detected value of the magnetic flux density and the set time when it is generated from the detected current value of the deflection magnet power supply. The set time t1 is determined in accordance with whether or not the signal is generated from the signal, and set in the cycle signal delay means 25.
[0058]
The synchronization means 27 receives the reference clock (FIG. 2 (d)) and outputs a synchronization clock synchronized with the cycle signal from the cycle signal delay means 25 as shown in FIG. 2 (e).
[0059]
The reference clock is normally output at a rate of one pulse when the magnetic flux density increases by a certain amount, and no pulse is output when it decreases. By counting this reference clock, it is possible to detect a change in the strength of the magnetic field. The change in the strength of the magnetic field indicates the increment of energy given to the particle, that is, the increment of energy given to the particle can be known by counting this reference clock.
[0060]
The delay counter 29 receives the synchronization clock synchronized with the cycle signal by the synchronization means 27, and outputs the trigger signal after inputting the synchronization clock of the same number C1 (FIG. 2 (e)) as the set count value. It resets itself and the synchronizing means 27 to prepare for the trigger signal output of the next cycle.
[0061]
Therefore, by appropriately setting the set count value of the delay counter 29, ions can be incident / extracted at a desired energy level. Usually, the ion incidence timing is preferably when the magnetic field intensity of the deflecting electromagnet is the lowest, so that an incident trigger signal is output when the initial pulse of the synchronous clock is input.
[0062]
The count value set in the delay counter 29 is changed by the set count value changing unit 37.
[0063]
The number of trigger signals, that is, the number of cycles of the cycle signal is controlled by the cycle suppression means 39. That is, by suppressing the number of cycles to an appropriate number by the cycle suppressing means 39, the amount of beam required by the utilization system 17 can be guided to the utilization system 17 through the incident-acceleration-exit process.
[0064]
The set count value changing unit 37 and the cycle suppressing unit 39 receive information on the emission count and the number of cycles according to the usage of the utilization system 17 from the beam amount control unit 41.
[0065]
The beam amount control means 41 refers to the beam amount set value file 43 in accordance with the use application, determines the number of cycles and the emission count, and outputs them to the cycle suppression means 39 and the set count value change means 37, respectively. The amount and energy of the beam are controlled via the suppression means 39 and the set count value changing means 37.
[0066]
FIG. 10 shows a data configuration example of the beam amount setting value file 43. The beam amount setting value file 43 stores the number of cycles and the emission count for each pattern number. The number of cycles indicates the number of incident-acceleration-exit cycles, whereby the amount of beam guided to the utilization system 17 can be defined. The emission count indicates the set count value of the delay counter 29 for the emitter, and thereby the energy level for accelerating the beam can be defined. Therefore, the beam amount setting value file 43 is equivalent to storing various combinations of beam amounts and beam energy with pattern numbers.
[0067]
Therefore, the beam amount control unit 41 is given a pattern number according to the usage, and the cycle number and the emission count instructed to the cycle suppression unit 39 and the set count value changing unit 37 based on the beam amount setting value file 43. Can be determined.
[0068]
In the utilization system 17, it is necessary to change the amount and energy level of the beam according to the application, and in some applications, the amount and energy of the beam may be changed sequentially. In order to carry out this easily, an operation plan control means 45 for sequentially providing a pattern number corresponding to the beam amount and the energy level to the beam amount control means 41 is provided for each application.
[0069]
The beam amount control means 41 sets the set count value related to the energy level corresponding to the given pattern number to the set count value changing means 37 as described above, and sets the cycle number related to the beam amount corresponding to the pattern number to the cycle suppression means. 39 is loaded. The beam amount control means 41 repeats this operation every time a pattern number is given from the operation plan control means 45.
[0070]
The operation plan control means 45 needs to quickly give the pattern number to the beam amount control means 41 for many applications. At this time, it is convenient if a combination of pattern numbers for each application is stored in advance in the emission target file 47 and necessary pattern numbers can be sequentially extracted from the emission target file 47.
[0071]
FIG. 11 shows an example of the data structure of the extraction target file 47. The extraction target file 47 irradiates the patient with a beam as an application and the number of patterns irradiated to the patient. It shows that it is composed of information indicating whether it is a number. For example, for patient A, there are three types of pattern numbers, indicating that patient A is irradiated in the order of pattern numbers 2, 5, and 4.
[0072]
Further, when making an operation plan, it is convenient to record a record of what beam is used in the utilization system 17. Therefore, the operation plan control means 45 records the operation results in the operation result record file 49 as shown in FIG. In FIG. 12, the data structure of the operation record file 49 is equivalent to the structure of the emission target file 47 with the irradiation date added.
[0073]
In the above configuration, the operation plan control unit 45 transmits the pattern number to the beam amount control unit 41 based on the emission target file 47, and the beam amount control unit 41 based on the received pattern number and the beam amount setting value file 43. The number of cycles and the emission count corresponding to the beam amount and beam energy required by the utilization system 17 are determined and notified to the cycle suppression means 39 and the set count value change means 37, respectively.
[0074]
The set count value changing unit 37 loads the emission count instructed from the beam amount control unit 41 onto the delay counter 29 and changes the set count value. That is, the energy level required by the utilization system 17 is accelerated.
[0075]
The cycle suppression unit 39 monitors the output status of the cycle signal from the cycle signal generation unit 23 based on the number of cycles instructed from the beam amount control unit 41. 8, the gate in the cycle signal generating means 23 is opened to suppress the output of the cycle signal. That is, the amount of beams required by the utilization system 17 is guided to the utilization system 17 through an incident-acceleration-exit process.
[0076]
In addition, in the case where the patient is irradiated with a cancer cell on an organ that is constantly moving, such as the lung or heart, the beam is irradiated only when the target cancer cell moves on the irradiation target. There is a need. In this case, the cycle signal generation means 23 generates a cycle signal only while it is permitted by the cycle permission means 55.
[0077]
The cycle permission unit 55 is turned on only when the irradiation target cancer cell is on the irradiation target from the heartbeat signal generation unit 59 when the irradiation target is the heart or from the respiratory signal generation unit 61 when the irradiation target is the lung. Only when the permission signal is ON, the cycle signal generating means 23 is permitted to output the cycle signal.
[0078]
Similarly, the emitter synchronizer 57 receives a permission signal that is turned on only when the cancer cell to be irradiated is on the irradiation target from the heartbeat signal generator 59 or the respiratory signal generator 61, and the permission signal is in the ON state. Only when the trigger signal from the delay counter 29 for the emitter is transmitted to the emitter 11. In the incident-acceleration-extraction process, when the permission signal is ON at the incident timing and OFF at the extraction timing, the incident and accelerated ions are high in the ejector 11 in FIG. Instead of being emitted to the energetic particle transport system 13, it is discharged from the acceleration ring 5 to the outside by a discharge means (not shown).
[0079]
FIG. 13 shows a timing chart of the permission signal when the affected part is the heart. In the case where the heart changes such as the heart or its surroundings, the permission signal is assumed to be synchronized with the heartbeat. As shown in FIG. 13A, the heartbeat signal can be detected from the body surface as an electrical signal. The heartbeat signal generating means 59 inputs the heartbeat signal detected from the body surface, and outputs a permission signal as shown in FIG.
[0080]
The heartbeat signal generating means 59 can be configured by a circuit as shown in FIG. 14, for example. In FIG. 14, the heartbeat signal generating means 59 converts the heartbeat signal into a pulse signal by the comparator 59a, and the pulse width is obtained by the monomulti 59b only during a time t3 (see FIG. 13B) where the affected part is considered to exist on the irradiation target. Extend. FIG. 13C shows an approximately 20 Hz sine wave signal input by the cycle signal generating means 23, and indicates that only the cycle signal corresponding to the time t3 when the permission signal is ON can be input / output.
[0081]
FIG. 15 shows a timing chart of the permission signal in the case where the affected part is the lung. In the case of a part that fluctuates due to breathing in or around the lung, the lung contracts due to breathing. Install a strain gauge around. When the lung expands, the strain gauge is extended and the resistance value increases, and when the lung contracts, the resistance value decreases. Therefore, the contraction of the lung can be detected by the change in the resistance value.
[0082]
The respiratory signal generating means 61 is constituted by a comparator as shown in FIG. 16, for example. As shown in FIG. 15 (a), the voltage value at the resistance wire obtained by passing a constant current through the strain gauge is input. When the voltage value is equal to or higher than a predetermined threshold value, a permission signal as shown in FIG. FIG. 15C shows an approximately 20 Hz sine wave signal input by the cycle signal generating means 23.
Further, the exit magnet control means 51 inputs the same exit count loaded in the emitter delay counter 29 from the set count value changing means 37, and from this value, the beam emitted from the emitter 11 becomes a high-energy particle. The magnetic field strength of the extraction system magnet 15 that smoothly passes through the transport system 13 is calculated and set as the power source of the extraction system magnet 15. Thereby, the magnetic field intensity of the output system magnet 15 can be adjusted according to the energy level of the output beam.
[0083]
At that time, the outgoing magnet control means 51 makes an inquiry to the outgoing magnet setting value file 53 as shown in FIG. 17 and takes in the magnetic field strength stored therein, so that the magnetic field strength corresponding to the energy level of the beam is reduced for a short time. Can be obtained.
[0084]
In FIG. 17, the output system magnet setting value file 53 stores a set voltage value for the power supply of the plurality of output system magnets 15 for every 50 counts of the output count, that is, the set value count value of the delay counter 29. Yes. In this case, when the emission count from the setting count value changing means 37 is not defined in the extraction system magnet setting value file 53, the data defined before and after that is taken out from the extraction system magnet setting value file 53, A method of obtaining the set voltage value by interpolation calculation can be taken.
[0085]
As is clear from the above description, according to the present embodiment, even when a resonant power source is used as the power source for the deflecting electromagnet, the particle accelerator is incident at an optimum timing in synchronization with the magnetic field change cycle of the deflecting electromagnet. , Acceleration and extraction operations can be controlled.
[0086]
In addition, the amount and energy of the charged particles emitted can be easily changed according to the usage application.
[0087]
Furthermore, even when the irradiation target is a part that varies due to heartbeat or respiration, the charged particle beam can be accurately emitted only to the irradiation target part.
[0088]
【The invention's effect】
As described above, according to the present invention, even when a power source that changes the current value supplied like a resonant power source is used as a power source for the deflection electromagnet, the particle accelerator is incident in synchronization with the magnetic field change cycle of the deflection electromagnet. The operation timing of acceleration and extraction can be controlled.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a first embodiment of a timing control apparatus for a particle accelerator according to the present invention.
FIG. 2 is a timing chart for explaining basic operations of the timing control device shown in FIG. 1;
FIG. 3 is a circuit diagram showing a configuration example of a current detection unit 31 shown in FIG.
4 is a diagram showing waveforms of signals IA, V1B, and V1C of the circuit shown in FIG.
5 is a diagram showing a low-pass filter used as the current value filter or the magnetic flux density value filter shown in FIG. 1. FIG.
6 is a circuit diagram showing a configuration example of the magnetic flux density detection means 33 shown in FIG. 1. FIG.
7 is a diagram showing waveforms of signals BA, V2B, and V2C of the circuit shown in FIG.
8 is a circuit diagram showing a configuration example of cycle signal generating means shown in FIG. 1. FIG.
9 is a diagram showing a signal processing process in the circuit shown in FIG. 8;
10 is a diagram showing a data configuration example of a beam amount setting value file shown in FIG. 1. FIG.
11 is a diagram showing a data configuration example of an extraction target file shown in FIG. 1. FIG.
12 is a diagram showing a data configuration example of an operation record recording file shown in FIG. 1. FIG.
FIG. 13 is a timing chart for explaining generation of a permission signal when an affected part is a heart.
14 is a circuit diagram showing a configuration example of a heartbeat signal generating means shown in FIG. 1. FIG.
FIG. 15 is a timing chart showing generation of a permission signal when an affected part is a lung.
16 is a circuit diagram showing a configuration example of a respiratory signal generation unit shown in FIG. 1. FIG.
17 is a diagram showing a data configuration example of an output magnet setting value file shown in FIG. 1. FIG.
FIG. 18 is a diagram schematically showing a configuration of a particle accelerator.
FIG. 19 is a time chart illustrating timing control of a conventional particle accelerator.
[Explanation of symbols]
11 ……… Ejector
15 ... Extraction magnet
19 ......... Particle accelerator
23... Cycle signal generating means
25... Cycle signal delay means
27 ....... Synchronization means
29 ……… Delay counter
31... Current detection means
33 ... Magnetic flux density detection means
35... Cycle signal delay adjusting means
37... Setting count value changing means
39 .... Cycle suppression means
41... Beam amount control means
43 ......... Beam amount setting value file
45 .... Operation plan control means
47 ……… Target file
49 ……… Operation record file
51... Output system magnet control means
53 .... Extraction magnet setting file
55 .... Cycle permission means
57... Emitter synchronization means
59 ......... Heart rate signal generating means
61 .... breathing signal generation means

Claims (8)

An injector for injecting charged particles into the acceleration ring; acceleration means for accelerating the incident charged particles to a predetermined energy; and a deflecting electromagnet for deflecting the charged particles to circulate in the acceleration ring; In addition, in the particle accelerator timing control device for controlling the operation timing of each device related to the incidence, acceleration and emission of the particle accelerator including the emitter for emitting the charged particles from the acceleration ring to the utilization system,
The deflection electromagnet is supplied with a current that changes in a sinusoidal form from an electromagnet power source, and forms a magnetic field in which the magnetic flux density changes in a sinusoidal form in accordance with the change in the current,
Sine wave signal detection means for detecting a sine wave signal corresponding to a change in the magnetic field of the deflection electromagnet;
A cycle signal output means for inputting the sine wave signal and outputting a pulsed cycle signal near the lowest value of the sine wave signal;
A synchronization means for inputting a reference clock in which a pulse appears at a rate of one pulse when the magnetic flux density is increased by a certain amount, and outputting a synchronization clock in synchronization with the cycle signal;
Trigger signal output means for outputting a trigger signal of each device related to the incidence, acceleration and emission according to a preset count value based on the synchronous clock;
In response to said utilization system applications, timing control system for particle accelerator, characterized by comprising a set count value changing means for changing an emission count value set in the trigger signal output means. Depending on the application of the available system timing control of particle accelerator according to claim 1, characterized by comprising a cycle suppression means for suppressing a predetermined number of cycles the number of cycle signal output from the cycle signal output means apparatus. Based on the beam amount setting value file and a beam amount setting value file stored in advance by patterning a combination of the number of cycle signals output from the cycle signal output means and the emission count value set in the trigger signal output means Te, claim 1, characterized in that it comprises a beam quantity control means for the selected pattern of the combination according to the usage-based applications, to control the amount and energy of charged particles emitted in the utilization system or 2 SL placing the timing control system for particle accelerator. The beam amount control means according to the emission target file in which the operation plan information designating the combination pattern is registered for each emission target of the utilization system, and the operation plan information of the emission target designated in the emission target file 4. The particle accelerator timing control apparatus according to claim 3 , further comprising operation plan control means for providing information for selecting the combination pattern. The cycle signal output means inputs the sine wave signal, and outputs a pulsed cycle signal when the sine wave signal falls below a threshold, and a cycle from the cycle signal generation means timing control system for particle accelerator according to any one of claims 1 to 4, characterized in that it has a cycle signal delay means for delaying the signal output at the optimum value near the minimum value of the sinusoidal signal . Only when the permission signal is generated, the permission signal generating means for monitoring the position of the irradiation target part that fluctuates at a substantially constant rhythm, and generating a permission signal when the irradiation target part is at a predetermined irradiation position, timing control system for particle accelerator according to any one of claims 1 to 5, characterized in that it comprises a cycle permitting means for permitting the output of the cycle signal from the cycle signal output means. 7. The particle accelerator timing according to claim 6 , further comprising an emitter synchronizer for transmitting an emission trigger signal from the trigger signal output means to the emitter only while the permission signal is generated. Control device. In accordance with the emission count value set in the trigger signal output means, the intensity of the magnetic field of the emission magnet for guiding charged particles from the emitter to the utilization system is calculated, and the power supply of the emission magnet is turned on. timing control system for particle accelerator according to any one of claims 1 to 7, characterized in that it comprises the emission magnet control means for controlling.

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