JP2002151300A - Tune display device and circular accelerator system having same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tune display device and a circular accelerator system having the same which can operate a control easily to keep the tune away from a resonant point. SOLUTION: A betatron vibration amplitude is increased with impressing high-frequency electromagnetic field by a high-frequency impressing electrode 16 to charged particles beam going round a synchrotron 1, an orbit displacement of the charged particles beam with increased betatron vibration amplitude is detected by a position monitoring electrode 18, and a signal processing device 5 calculates a tune of charged particles beam based on the detected orbit displacement by the position monitoring electrode 18. A time change of the calculated tune and a parameter time change relating to a machine structuring the synchrotron 1, are displayed on the same time axis by a display device 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tune display device for displaying the tune of a charged particle beam accelerated while orbiting in a circular accelerator, and a circular accelerator system having the same.

[0002]

2. Description of the Related Art In a circular accelerator represented by a synchrotron, a charged particle beam (hereinafter, referred to as a beam) is accelerated while rotating. The betatron frequency per round is called tune.
When this tune reaches a predetermined value, "resonance" occurs in which the betatron oscillation amplitude of the beam sharply increases. The value of the tune that causes resonance is called a resonance point. If the oscillation amplitude of the beam continues to increase due to this resonance, the beam eventually hits a vacuum duct or the like and is lost. Therefore, it is necessary to keep the beam tune away from the resonance point.

[0003] Techniques have been devised for measuring the tune of a circulating beam in order to control the tune. For example, Japanese Patent Application Laid-Open No. Hei 5-3100 discloses a technique for measuring the tune of a beam using an RF knockout method. It is described that it is displayed. Specifically, a high-frequency signal is applied to an electrode for generating an electric field while changing the frequency, and an output level for each frequency of a signal obtained from the detection electrode is obtained and displayed according to the changing beam position. .

[0004]

The above prior art does not specifically describe a tune display method. However, even if the tune value is simply displayed, any device is required to keep the tune away from the resonance point. It is difficult to judge how to control.

[0005] It is an object of the present invention to provide a tune display device and a circular accelerator system having the tune display device, which can easily perform control for moving the tune away from the resonance point.

[0006]

A feature of the present invention that achieves the above object is that a charged particle beam accelerated while circulating in a circular accelerator composed of a plurality of instruments is changed over time and parameters related to the instruments are changed. Is displayed on the same time axis.

[0007] Since the time change of the tune and the time change of the parameter relating to the device are displayed on the same time axis, the change in the tune can be confirmed in association with the state of the device. It is easy to determine at what timing and how should be controlled. Therefore, control for keeping the tune away from the resonance point can be easily performed.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. (Embodiment 1) FIG. 1 shows a configuration of a circular accelerator system which is a preferred embodiment of the present invention. In the circular accelerator system of the present embodiment, a low-energy charged particle beam (hereinafter, referred to as
A synchrotron 1 is used as a circular accelerator after the incident beam is accelerated to a predetermined energy.

First, the equipment constituting the synchrotron 1 will be described. The injector 11 makes the low-energy beam emitted from the pre-accelerator 4 incident on the synchrotron 1. The deflection electromagnet 12 deflects the beam incident on the synchrotron 1, adjusts the trajectory of the beam, and orbits the beam. The quadrupole magnet 13 includes a quadrupole diverging electromagnet that diverges the beam in the horizontal direction and converges in the vertical direction, and a quadrupole focusing magnet that diverges the beam in the vertical direction and converges in the horizontal direction, and adjusts the tune of the circulating beam. . The horizontal direction refers to a direction perpendicular to the beam traveling direction and horizontal to the deflection surface of the deflection electromagnet 12, and the vertical direction refers to a direction perpendicular to the beam traveling direction and perpendicular to the deflection surface of the deflection electromagnet 12. . The same applies to the following description.

The high-frequency accelerating cavity 14 gives energy to the orbiting beam by applying a high-frequency electric field to the beam and accelerates the beam to a predetermined energy. The hexapole electromagnet 15 is excited after the end of the beam acceleration,
While the hexapole electromagnet 15 is excited, the high frequency applying electrode 16 applies a high frequency electromagnetic field to the circulating beam to increase the betatron oscillation amplitude of the beam. Hexapole electromagnet 15
The tune of the beam changes in accordance with the increase in the vibration amplitude due to the effect of the hexapole magnetic field generated by the, and the beam at which the tune reaches the resonance point causes resonance. Outgoing deflector 17
Deflects the beam whose oscillation amplitude is increased by resonance and emits the beam from the synchrotron 1.

Synchrotron 1 configured as above
Is guided to an irradiation device 7 for irradiating the affected part of the cancer patient with the beam, and used for cancer treatment.
In FIG. 1, the power source 21 includes a bending electromagnet 12, a quadrupole electromagnet 13, a high-frequency accelerating cavity 14, and a hexapole electromagnet 15.
The power supply 22 supplies power (high-frequency signal) to the high-frequency application electrode 16. These power supplies 21 and 22 are controlled by the control device 3. The position monitoring electrode 18 is an electrode for measuring the position of the beam circulating in the synchrotron 1. The signal from the position monitoring electrode 18 is processed by the signal processing device 5, and the beam is transmitted to the display device 6. Displays the position measurement result.

In such a synchrotron 1, before actual operation (emission of a beam and treatment of a patient), test operation (beam operation) for confirming whether a desired beam can be emitted with a predetermined operation plan is performed. Adjustment), at which time the tune of the beam is measured.

Here, the concept of tune measurement in this embodiment will be described. When a high-frequency electromagnetic field is applied to the beam, the oscillation amplitude of the beam having a tune corresponding to the frequency of the high-frequency electromagnetic field increases. Therefore, the tune of the beam can be known by detecting the increase in the oscillation amplitude. The principle is as follows.

When a frequency component of a signal obtained by the position monitoring electrode 18 when a high-frequency electromagnetic field is applied to the beam is analyzed, it is found that a spectrum as shown in FIG. 2A is obtained. As shown in FIG. 2A, the frequency nf (n = 1, 2,...) Of n times the orbital frequency f of the beam and (n−ν)
The signal intensity increases at f and (n + ν) f. Here, ν is a decimal part of the tune. From this, nf and (n−
If ν) f or (n + ν) f is known, the tune ν can be obtained by (Equation 1) or (Equation 2).

[0015]

(Equation 1)

[0016]

(Equation 2)

At this time, in principle, any value may be selected as n. However, in reality, if n is small, the spectrum is detected by the influence of noise existing at a high level in a low frequency region. Becomes difficult. Conversely, when n is large, the frequency change at the time of beam acceleration increases as shown in FIG. 2B, so that the frequency band at the time of frequency spectrum analysis must be widened. High resolution is required over a wide frequency range.
An appropriate n may be set in consideration of the above two points. In the present embodiment, n is set to 2 and is set in the control device 3 in advance.

When n is determined, the frequency band of the high-frequency electromagnetic field applied from the high-frequency application electrode 16 to the beam can be determined. The frequency band of the high-frequency electromagnetic field is the lowest frequency f obtained by (Equation 3) when the circulating frequency of the beam before acceleration is fa and the circulating frequency of the beam after acceleration is fb.
The frequency band may be from l to the maximum frequency fh obtained by (Equation 4). By setting the frequency band in this manner, the vibration amplitude of the beam can be increased at any time from before the acceleration of the beam to the end of the acceleration, and continuous tune measurement can be performed.

[0019]

(Equation 3)

[0020]

(Equation 4)

Next, a specific method of tune measurement based on the above concept will be described. In the tune measurement at the time of the test operation, a high-frequency electromagnetic field is applied to the beam when the beam injection is completed. In this embodiment, a high-frequency electromagnetic field for tune measurement is applied to the beam by the high-frequency application electrode 16 used at the time of beam emission. In this embodiment, the tune in the horizontal direction is measured.

FIG. 3 shows the high frequency applying electrode 16 and its power supply 22. The control device 3 includes an oscillator 221 of the power supply 22.
Indicates the frequency band of the high-frequency signal to be output.
The control device 3 also indicates the frequency of the high-frequency electric field applied to the beam from the high-frequency accelerating cavity 14, and the frequency is the orbital frequency obtained from the energy of the beam. It can be used for setting the frequency of the high-frequency electromagnetic field. Since the high-frequency accelerating cavity 14 must apply a high-frequency electric field corresponding to the orbital frequency at that time in order to accelerate the beam, the high-frequency accelerating cavity 14 determines the time of incidence based on the beam energy at the time of incidence and the beam energy at the end of acceleration. And the circulating frequency fb at the end of acceleration are set in the control device 3 in advance. By substituting the preset circulating frequencies fa and fb into the above (Equation 3) and (Equation 4), the lowest frequency fl and the highest frequency fh of the frequency band indicated to the oscillator 221 are obtained. The control device 3 calculates the maximum frequency f from the lowest frequency fl obtained by (Expression 3) and (Expression 4).
The oscillator 221 is controlled so as to output a high-frequency signal having a frequency band up to h. (Equation 3) and (Equation 4)
Is the design value of the horizontal tune, and may be different from the actual horizontal tune. Therefore, considering the margin, the minimum frequency fl is more than the value obtained by (Equation 3). It is desirable that the frequency be smaller and the maximum frequency fh be larger than the value obtained by (Equation 4). Specifically, as shown in FIG.
Is set.

The oscillator 221 is controlled by the control device 3 and outputs a high-frequency signal having a frequency band from fl to fh to the amplifier 222. The amplifier 222 includes an oscillator 221
Is amplified and applied to the high-frequency application electrode 16. The amplification factor in the amplifier 222 is adjusted by the control device 3 so that the oscillation amplitude of the beam does not suddenly increase and the beam current does not abruptly attenuate.

The high-frequency applying electrode 16 to which the high-frequency signal is applied from the amplifier 222 generates a high-frequency electromagnetic field having a frequency component of the high-frequency signal, and the high-frequency electromagnetic field is applied to a beam passing between the two electrodes 16. At this time, the hexapole electromagnet 15 is in a non-excited state. Note that the electrode 16 of the present embodiment is an electrode for increasing the vibration amplitude of the beam in the horizontal direction.

The trajectory of the beam to which the high-frequency electromagnetic field is applied changes due to an increase in the amplitude of the vibration in the horizontal direction. The change causes a change in the voltage induced in the position monitoring electrode 18. FIG. 4 shows the position monitoring electrode 18 and the signal processing device 5.
Is shown. As shown in the figure, the position monitoring electrode 18 is a triangular electrode 1 provided so as to face the beam.
81L, 181R, 182L, and 182R. The electrodes 181L and 182L are electrically connected, and the electrodes 181R and 182R are electrically connected.
Then, a signal corresponding to the voltage induced on the electrodes 181L and 182L and a signal corresponding to the voltage induced on the electrodes 181R and 182R are input to the position detection circuit 51 of the signal processing device 5.

The position detection circuit 51 calculates the difference between the two input signals and outputs the obtained difference signal to the spectrum measurement circuit 52. The spectrum measurement circuit 52 analyzes the frequency components of the input difference signal and measures the signal strength of each frequency component. Since the frequency band analyzed by the spectrum measuring circuit 52 may be the same as the frequency band of the high-frequency electromagnetic field applied to the beam, the minimum frequency fl and the maximum frequency fh instructed by the control device 3 to the oscillator 221 are determined. And set the frequency band based on it. The frequency spectrum obtained by the spectrum measuring circuit 52 is as shown in FIG.

The frequency spectrum data obtained by the spectrum measurement circuit 52 is input to a tune calculation circuit 53. The tune calculation circuit 53 extracts nf from the input frequency spectrum data. In extracting nf, the tune calculation circuit 53 first takes in the orbital frequency fa and the value of n at the time of beam incidence from the control device 3. The orbital frequency fa given by the control device 3 is a calculated value obtained according to the beam energy at the time of incidence, and n is set to 2 in this embodiment. Although nf can be obtained from fa and n given by the control device 3, since the circulating frequency may be different between the calculated value fa and the actual value, nf can be obtained by calculation from the data of the frequency spectrum. Then, a frequency having the highest signal strength is searched for near nf, and the frequency is extracted as nf. In addition, since the signal intensities of (n−ν) f and (n + ν) f are also prominent, a frequency in which the signal strength protrudes near the extracted nf is searched on both the low frequency side and the high frequency side, and (n + ν) ) Determine f and (n−ν) f.

Nf, (n−ν) thus determined
By substituting f, (n + ν) f into (Equation 1) and (Equation 2), two tunes ν are obtained. At this time, if the correct nf, (n−ν) f, and (n + ν) f are selected, the two tunes ν should be equal, and if the same tune ν is obtained, the tune calculation is performed. The data is stored in a memory (not shown) of the circuit 53. On the other hand, if the two tunes ν obtained by (Equation 1) and (Equation 2) have different values, it is highly likely that (n−ν) f or (n + ν) f has been erroneously determined. , 2
One tune is compared with the tune design value, and the one that is significantly different from the design value is determined to be an error. Then, (n−ν) f or (n + ν) f that caused the error is determined again. Specifically, other frequencies protruding in the vicinity of (n−ν) f or (n + ν) f determined erroneously are represented by (n−ν) f.
ν) f or (n + ν) f. (N-
When ν) f or (n + ν) f is determined again, the tune ν is calculated again, and this operation is repeated until the two tunes ν become equal.

The above-described tune measurement is continuously performed from the completion of the beam incidence to the end of the acceleration in the test operation, and the time change (time series data) of the tune is measured and stored in the memory. Specifically, a high-frequency electromagnetic field is continuously applied from the high-frequency application electrode 16 from the completion of the incidence to the end of the acceleration, and the signal processing device 5 performs the above-described signal processing in a cycle as short as possible, thereby changing the time of the tune. Is measured. In the signal processing of the signal processing device 5, the second and subsequent determinations of nf may be made by searching for a frequency where the signal strength is prominent near the previously determined nf. Further, at the time of the second and subsequent tune calculations, it may be determined that the difference between the previously calculated tune and the previously calculated tune is incorrect, without using the design value, in order to check whether the obtained tune is correct.

When the tune measurement from the completion of the incidence to the end of the acceleration is completed, the tune calculation circuit 53 outputs the tune time-series data stored in the memory to the display device 6. The display device 6 compares the input tune time-series data with the parameters of the equipment constituting the synchrotron 1 (the excitation current B of the bending electromagnet, the excitation current QD of the quadrupole diverging electromagnet).
And the excitation current QF of the quadrupole focusing electromagnet and the beam parameters (current value IDC). FIG. 5 shows an example of the display screen. As shown, the tune and each parameter are displayed on the same time axis. The parameters (currents for exciting the bending electromagnet, the quadrupole diverging electromagnet, and the quadrupole converging electromagnet) of the devices constituting the synchrotron 1 and the parameters (current values) of the beam are given from the control device 3.

According to the present embodiment, the tune is displayed together with the parameters of the equipment constituting the synchrotron 1 such as the exciting currents of the bending electromagnet, the quadrupole diverging electromagnet and the quadrupole focusing electromagnet, and the beam parameters such as the beam current value. The relationship between the state of the beam and the change in tune becomes clear, and it is easy to determine which device should be controlled and how to move the tune away from the resonance point, and it is easy to control the movement of the tune away from the resonance point. It can be carried out.

Further, according to the present embodiment, a high-frequency electromagnetic field for measuring tune is generated by using the high-frequency application electrode 16 provided for beam emission, so that a new electrode is provided for tune measurement. It is not necessary, and the number of devices constituting the synchrotron 1 can be reduced. Further, since the position monitoring electrode 18 used for measuring the beam position is used for tune measurement, the number of devices constituting the synchrotron 1 can be reduced. Therefore, the cost and size of the synchrotron 1 can be reduced.

The control device 3 of this embodiment may have the function of the signal processing device 5. Embodiment 2 A circular accelerator system according to another embodiment of the present invention will be described with reference to FIGS. The circular accelerator system according to the present embodiment is different from the first embodiment in that a time change is displayed on the display device for the vertical tune in addition to the horizontal tune. Hereinafter, differences from the first embodiment will be described.

The overall configuration of the circular accelerator system of this embodiment is the same as that of the first embodiment (FIG. 1), but the configurations of the power supply 22 and the high-frequency application electrode 16 are different from those of the first embodiment. FIG. 6 shows the configuration of the power supply 22 and the high-frequency application electrode 16 of this embodiment. As described above, in the present embodiment, in order to measure the tune in the horizontal direction and the vertical direction, it is necessary to increase the amplitude of the horizontal and vertical vibrations of the beam. For this purpose, the high-frequency application electrode 16 of the present embodiment includes two sets of high-frequency application electrodes 16x and 16y opposed to each other with a beam interposed therebetween.
The high-frequency application electrode 16x is an electrode that generates a high-frequency electromagnetic field for increasing the vibration amplitude in the horizontal direction,
The high-frequency application electrode 16y is an electrode for generating a high-frequency electromagnetic field for increasing the vertical vibration amplitude.

In this embodiment, since the horizontal tune and the vertical tune are measured separately, first, the case of measuring the horizontal tune will be described. When the beam incidence in the test operation is completed, the control device 3 first controls the switching circuit 223 to connect the terminals a and b. By connecting the terminal a and the terminal b, the high-frequency signal output from the power supply 22 is output to the high-frequency application electrode 16x, so that the horizontal vibration amplitude can be increased. Next, the control device 3 controls the oscillator 221. The operation thereafter is the same as that of the first embodiment, and the description is omitted.

FIG. 7 shows the position monitoring electrode 18 of this embodiment.
And a configuration of the signal processing device 5. As shown in the figure, the position monitoring electrode 18 of the present embodiment outputs signals according to the trajectory displacement of the beam in the horizontal direction.
R, 182L, 182R, and 183U, 183D, which output signals corresponding to the orbital displacement of the beam in the vertical direction,
184U and 184D. The position monitoring electrodes 183U and 184U are electrically connected, and the position monitoring electrodes 183D and 184D are also electrically connected.

In measuring the horizontal tune,
The control device 3 controls the switching circuit 54 of the signal processing device 5 to connect the terminal d to the terminal h and the terminal f to the terminal i. Thus, the position monitoring electrodes 181L and 182L
And a signal corresponding to the voltage induced on the position monitoring electrodes 181R and 182R is input to the position detection circuit 51. Subsequent operations are the same as in the first embodiment, and a description thereof will not be repeated.

When the measurement of the horizontal tune is completed, the measurement of the vertical tune is performed next. In the present embodiment, in order to measure the vertical tune, the same test run as when the horizontal tune was measured is performed again. When the beam injection in the test operation is completed, the control device 3 first controls the switching circuit 223 to connect the terminals a and c. By connecting the terminal a and the terminal c, the high-frequency signal output from the power source 22 is applied to the high-frequency application electrode 16.
Since the signal is output to y, the vibration amplitude in the vertical direction can be increased. Next, the control device 3 controls the oscillator 221, and determines the frequency band of the high-frequency signal to be output from the oscillator 221 using (Equation 3) and (Equation 4) as in the case of the horizontal tune measurement. I do. However, the calculation is performed using the design value of the vertical tune as the tune ν. Subsequent operations are the same as those in the case of the horizontal tune measurement, and a description thereof will be omitted.

In measuring the vertical tune,
The control device 3 controls the switching circuit 54 of the signal processing device 5 to connect the terminal e to the terminal h and the terminal g to the terminal i. As a result, the position monitoring electrodes 183U and 184U
And a signal corresponding to the voltage induced on the position monitoring electrodes 183D and 184D is input to the position detection circuit 51. Subsequent operations are the same as in the case of the horizontal tune measurement, and a description thereof will be omitted.

When the time series data of the horizontal tune and the vertical tune is obtained in this way, the tune calculation circuit 53 outputs the time series data to the display device 6, and the display device 6 displays the time change of the tune. Display on the screen. FIG. 8 shows an example of display on the display screen. As shown in the figure, the input time-series data of the horizontal tune νx and the time-series data of the vertical tune νy are displayed on the display screen together with the exciting current and beam current values of the bending electromagnet, the quadrupole diverging electromagnet, and the quadrupole converging electromagnet. I do.

According to this embodiment, in order to display the parameters of the equipment constituting the synchrotron 1 and the parameters of the beam and the vertical tune on the same time axis, control for moving the vertical tune away from the resonance point is performed. Easy to do. It goes without saying that an effect similar to that of the first embodiment can be obtained together with this effect. (Embodiment 3) A circular accelerator system according to another embodiment of the present invention will be described with reference to FIGS. The circular accelerator system according to the present embodiment differs from the second embodiment in that the horizontal tune and the vertical tune are simultaneously measured. Hereinafter, points different from the second embodiment will be described.

FIG. 9 shows the power supply 22 and the high-frequency application electrode 16 of this embodiment. As shown in the figure, the power supply 22 of this embodiment includes two amplifiers 222 connected to an oscillator 221.
a, 222b, the amplifier 222a is connected to the high-frequency application electrode 16x, and the amplifier 222b is connected to the high-frequency application electrode 16y. With this configuration, the high-frequency signal output from the oscillator 221 is simultaneously applied to both the high-frequency application electrodes 16x and 16y, so that the horizontal vibration amplitude and the vertical vibration amplitude of the beam are simultaneously increased. Can be done. The frequency band instructed from the control device 3 to the oscillator 221 is a frequency band including both the frequency band required for the high-frequency electromagnetic wave in the horizontal direction and the frequency band required for the high-frequency electromagnetic wave in the vertical direction. .

FIG. 10 shows the position monitoring electrode 1 of this embodiment.
8 and the configuration of the signal processing device 5 are shown. As shown in the drawing, the signal processing device 5 of the present embodiment includes two position detection circuits 51.
a, 51b and two spectrum measuring circuits 52a, 52
b. Signals extracted from the position monitoring electrodes 181L and 182L and the position monitoring electrodes 181R and 182R are input to the position detection circuit 51a, and are output to the position monitoring electrodes 183U and 184U and the position monitoring electrode 183.
D and 184D are output from the position detection circuit 51.
b. The position detection circuit 51a receives the input 2
The difference between the two signals is obtained, and the obtained difference signal is output to the spectrum measuring circuit 52a. Spectrum measurement circuit 52a
Finds the frequency spectrum of the difference signal and outputs it to the tune calculation circuit 53. On the other hand, the position detection circuit 51b obtains a difference between the two input signals, and outputs the obtained difference signal to the spectrum measurement circuit 52b. The spectrum measurement circuit 52b obtains the frequency spectrum of the difference signal and outputs the frequency spectrum to the tune calculation circuit 53. Tune operation circuit 53
Calculates the horizontal tune from the frequency spectrum given from the position detection circuit 51a, calculates the vertical tune from the frequency spectrum given from the position detection circuit 51b, and calculates the calculated horizontal tune and vertical tune. Output to the display device 6. The display device 6 displays the tune together with the parameters of each device as in the second embodiment.

According to this embodiment, since the horizontal tune and the vertical tune are simultaneously measured, it is not necessary to perform the test operation twice, and the time required for the tune measurement can be reduced. (Embodiment 4) A circular accelerator system according to another embodiment of the present invention will be described with reference to FIG. The circular accelerator system according to the present embodiment differs from the first embodiment in that the tune is measured in an actual operation (irradiation of a beam to a patient). Hereinafter, differences from the first embodiment will be described.

In this embodiment, a tune is measured when a beam for irradiating a patient is incident on the synchrotron 1 and accelerated. The tune measurement method is the same as that in the first embodiment, and a description thereof will not be repeated. Signal processing device 5 of the present embodiment
Outputs the calculated tune value to the display device 6 and to the control device 3. The control device 3 compares the input tune value with a tune threshold value set in advance by the operator, and if the tune value provided from the signal processing device 5 exceeds the threshold value, the synchrotron 1 The emission of the beam is stopped. Specifically, the application of the high-frequency electromagnetic field for beam emission is stopped, and the driving device 8 is controlled to close the shutter 9 provided between the synchrotron 1 and the irradiation device 7. Shutter 9
Is for blocking the beam emitted from the synchrotron 1. As the threshold, a value that may affect the treatment of the patient is set. When the value of the tune given by the signal processing device 5 exceeds the threshold value, the control device 3 displays a warning on the display screen of the display device 6 that “the tune is out of the predetermined value”. Let it.

According to the present embodiment, when the tune deviates from the predetermined value, the beam emission from the synchrotron 1 is stopped and a warning is displayed on the display device 6, so that the cancer treatment can be performed safely.

In each of the embodiments described above, the circular accelerator system for treating cancer is described. However, the present invention is not limited to the circular accelerator system for treating cancer, but can be applied to a circular accelerator system for physical experiments and the like. is there.

The tune measuring device in the present invention refers to the high-frequency application electrode 16, the position monitoring electrode 18, and the signal processing device 5.

[0049]

According to the present invention, control for keeping the tune away from the resonance point can be easily performed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a circular accelerator system according to a preferred embodiment of the present invention.

FIG. 2 is a diagram showing a frequency spectrum of a signal obtained from a position monitoring electrode 18 of FIG.

FIG. 3 is a configuration diagram of a power supply 22 and a high-frequency application electrode 16 of FIG. 1;

4 is a configuration diagram of the position monitoring electrode 18 and the signal processing device 5 of FIG.

FIG. 5 is an example of a display screen on the display device 6 of FIG. 1;

FIG. 6 is a configuration diagram of a power supply 22 and a high-frequency application electrode 16 of a circular accelerator system according to another embodiment of the present invention.

FIG. 7 is a configuration diagram of a position monitoring electrode 18 and a signal processing device 5 of a circular accelerator system according to another embodiment of the present invention.

FIG. 8 is an example of a display screen on the display device 6;

FIG. 9 is a configuration diagram of a power supply 22 and a high-frequency application electrode 16 of a circular accelerator system according to another embodiment of the present invention.

FIG. 10 is a configuration diagram of a position monitoring electrode 18 and a signal processing device 5 of a circular accelerator system according to another embodiment of the present invention.

FIG. 11 is a configuration diagram of a circular accelerator system according to another embodiment of the present invention.

[Explanation of symbols]

1. Synchrotron, 3. Control device, 4. Pre-accelerator,
5 ... Signal processing device, 6 ... Display device, 7 ... Irradiation device, 11
... Injector, 12 ... Bending electromagnet, 13 ... Quadrupole electromagnet, 14
... High-frequency accelerating cavity, 15 ... Six-pole electromagnet, 16 ... High-frequency application electrode, 17 ... Ejector, 18 ... Position monitoring electrode, 2
1, 22 ... power supply.

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Kazuyoshi Saito 7-2-1, Omika-cho, Hitachi City, Ibaraki Prefecture F-term in Hitachi, Ltd. Electric Power & Electric Development Laboratory 2G085 AA13 BA11 CA03 CA27 CA29 4C082 AA01 AC05 AE02 AG43 AP01 AP12 AP20

Claims (5)

[Claims] 1. Displaying, on the same time axis, a time change of a tune of a charged particle beam accelerated while circulating in a circular accelerator constituted by a plurality of devices and a time change of a parameter related to the device. A tune display device. 2. A circular accelerator system comprising a plurality of devices and having a circular accelerator for accelerating while rotating a charged particle beam, a tune measuring device for measuring the tune of the orbiting charged particle beam, and the tune measurement. A circular accelerator system comprising: a display device that displays a time change of a tune measured by the device and a time change of a parameter related to the device on the same time axis. 3. A high-frequency application electrode for applying a high-frequency electromagnetic field to a circulating charged particle beam to increase the betatron oscillation amplitude of the charged particle beam;
A position monitoring electrode for detecting the orbital displacement of the charged particle beam whose betatron oscillation amplitude is increased by application of the high-frequency electromagnetic field, and a signal for calculating the tune of the charged particle beam based on the orbital displacement detected by the position monitoring electrode The circular accelerator system according to claim 2, further comprising a processing device. 4. The circular accelerator is a circular accelerator that emits an accelerated charged particle beam, and the high-frequency application electrode applies a high-frequency electromagnetic field to the charged particle beam when emitting the charged particle beam. The circular accelerator system according to claim 3, wherein 5. A circular accelerator for emitting an accelerated charged particle beam, wherein when the tune measured by the tune measuring device exceeds a preset threshold, the circular accelerator is charged. 3. The circular accelerator system according to claim 2, further comprising a control device for stopping emission of the particle beam.