JP2003086399A - Charged particle beam emitting apparatus, circular accelerator and circular accelerator system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charged particle beam emitting apparatus which can be miniaturized, cheaply produced, easily control emission and emit a good- quality charged particle beam. SOLUTION: The emitting apparatus comprises deflecting electromagnets 1, a sextupole electromagnet 2 which divides betatron oscillation of a charged particle beam into a stable region and a resonant region, an emission channel which takes out the charged particle beam from a circular orbital, and the sextupole electromagnet 2 and quadrupole electromagnets 3 which deflect a central momentum of the charged particle beam to a momentum uniquely determined from a magnetic field of the deflecting electromagnets 1 to narrow the stable region of the betatron oscillation, thereby transferring the charged particle beam to the resonant region of the betatron oscillation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charged particle beam emitting device for orbiting and emitting a charged particle beam, a circular accelerator, and a circular accelerator system.

[0002]

2. Description of the Related Art Generally, a charged particle beam in a circular accelerator orbits around a design orbit while performing betatron oscillation. At this time, there is a stability limit called separatrix as shown in FIG. 10 which will be described later, and the charged particle beam within the stability limit, that is, in the stable region makes a stable orbit, but the charged particle beam exceeding the stability limit vibrates. It has the property of increasing in amplitude and diverging. Since the charged particle beam is emitted by utilizing this property, in the conventional circular accelerator, a quadrupole electromagnet is used to bring the tune representing the betatron frequency per one revolution of the accelerator close to an integer ± 1/3. Are excited (third-order resonance).

FIG. 8 shows, for example, Nuclear Instruments an
d Methods in Physics Research A374 (1996), "S
low beam extraction by a transverse RF field with
AM and FM ", K. Noda et al., Pp.269-277, 270.
It is a figure which shows the equipment arrangement of the conventional circular accelerator of this kind shown in the page, 101 is a bending electromagnet, 102 is a figure.
Is a sextupole electromagnet for splitting the betatron oscillation into a stable region and a resonance region, 103 is a quadrupole electromagnet used for adjusting the betatron frequency and narrowing the stable region at the time of extraction, and 104 is an exit serving as an entrance of the exit channel. Electrostatic electrode, 105 is an extraction bump electromagnet used to bring the orbit of the charged particle beam closer to the electrode, 106 is a high frequency acceleration cavity for accelerating the charged particle beam, 107 is chromaticity (momentum of betatron frequency) It is a sextupole electromagnet used for adjusting (dependency).

FIG. 9 is a diagram showing an operation pattern of the circular accelerator shown in FIG. In the figure, the graph of 108 is the magnetic field strength of the deflection electromagnet 101, 109 is the magnetic field strength of the sextupole electromagnet 102, 110 is the magnetic field strength of the quadrupole electromagnet 103, and 11 is
1 is the electric field strength of the electrostatic electrode 104, and 112 is the magnetic field strength of the emitting bump electromagnet 105.

FIG. 10 is a diagram showing a separatorics (a boundary between a stable region of betatron oscillation and a resonance region) of 1/3 integer resonance in a phase space (a space in which the position and inclination of the charged particle orbit are coordinates). In FIG. 3, 113 a is a separatrix at the start of emission, 113 b is a separatrix immediately before the end of emission, and 114 is an electrode gap of the electrostatic electrode 104.

Next, the operation will be described. As shown in FIG. 8, the charged particle beam is accelerated by the increase of the magnetic field of the deflection electromagnet 101 and the action of the high-frequency acceleration cavity 106, and the magnetic field intensity 108 of the deflection electromagnet 101 and the extraction hexapole electromagnet 102.
The magnetic field intensity 109 is emitted for a certain period. During the emission period, the stable region of the betatron oscillation is separated by the change of the magnetic field strength 110 of the quadrupole electromagnet 103.
To narrow like the Separatrix 113b, the charged particles having a large amplitude of betatron oscillation are sequentially brought into a resonance state. The charged particles in the resonance state increase the amplitude of the vibration, and the electrode gap 1 along the extension line of the separatrix.
It reaches 14 and is taken out from the orbit.

The bump electromagnet 105 is a pulse electromagnet that excites like a magnetic field strength 112, and the orbit of the charged particle beam is made to approach the electrostatic electrode 104 at the time of extraction, and the charged particle beam being emitted collides with other portions of the circular accelerator. It is used to prevent

The emission of the charged particle beam ends when the stable region becomes zero, but if the emission is stopped in the middle of that, the direction of change of the magnetic field of the quadrupole electromagnet 103 can be quickly reversed or the quadrupole A method such as using a quadrupole electromagnet that rapidly generates a magnetic field having a polarity opposite to that of the electromagnet 103 is used.

As shown in FIG. 10, the inclination of the orbit of the charged particles reaching the electrostatic electrode 104 changes during the emission, so that the emittance (area in the phase space) of the emitted charged particle beam is shaded in the figure. Since the area becomes large as shown by, the emittance is reduced by changing the electrostatic electrode 104 like the electric field intensity 111 to correct the inclination of the trajectory.

[0010]

Since the conventional apparatus for emitting a charged particle beam is configured as described above, in order to reduce the emittance of the emitted charged particle beam, the electrostatic electrode 104 is being emitted during the emission. There is a problem in that the power must be changed, and the power supply for them must have a pattern control function.

Further, in order to stop the emission on the way, it is necessary to add a function of quickly reversing the changing direction of the exciting current of the quadrupole electromagnet 103 to the power source or to separately install a quadrupole electromagnet that operates at high speed. there were.

In addition, the bump electromagnet 105 must be used in order not to reduce the emission efficiency, and there are problems that it is difficult to downsize the accelerator in order to increase the manufacturing cost and secure the installation space.

The present invention has been made in order to solve the above problems, and it is possible to reduce the size, manufacture at a low cost, and easily adjust the emission, and emit a high-quality charged particle beam. It is an object of the present invention to obtain a charged particle beam emitting device, a circular accelerator, and a circular accelerator system capable of performing the above.

[0014]

According to the present invention, there is provided a deflection electromagnet for orbiting a charged particle beam along an orbit, and a region dividing means for dividing betatron oscillation of the charged particle beam into a stable region and a resonance region. Extracting means for extracting the charged particle beam from the orbit, and displacing the central momentum of the charged particle beam to narrow the stable region of the betatron oscillation, thereby causing the charged particle beam to undergo the betatron oscillation. It is a charged particle beam emitting device provided with a momentum displacement control means for moving to a resonance region.

Further, by generating a momentum dispersion function at least at the entrance portion of the emitting means, the orbit of the charged particle beam is circulated in synchronization with the deviation of the central momentum of the charged particle beam with respect to the deflection magnetic field when the charged particle beam is emitted. And the distance between the emitting means and the emitting means are changed.

Further, the direction of change of the momentum excursion of the charged particle beam with respect to the magnetic field of the deflection electromagnet is reversed to widen the stable region of betatron oscillation, thereby stopping the emission of the charged particle beam.

A high frequency accelerating cavity for accelerating the charged particle beam is further provided, and the momentum of the charged particle beam is changed by changing the frequency of the high frequency accelerating cavity while the magnetic field of the deflection electromagnet is constant. Control momentum excursions.

Further, a high frequency accelerating cavity for accelerating the charged particle beam is further provided, and the magnetic field of the deflecting electromagnet is changed while the frequency of the high frequency accelerating cavity is constant or an accelerating electric field is not generated in the high frequency accelerating cavity. Controls the momentum excursion of the charged particle beam with respect to the magnetic field.

Further, a high frequency accelerating cavity for accelerating the charged particle beam is further provided, and the momentum of the charged particle beam with respect to the magnetic field is changed by simultaneously or sequentially changing the frequency of the high frequency accelerating cavity and the magnetic field of the deflection electromagnet. Control the excursion.

Also, the emittance of the charged particle beam emitted from the emitting means is adjusted by adjusting the relationship between the momentum excursion of the charged particle beam and the betatron frequency.

Further, according to the present invention, a duct including a circular orbit around which the charged particle beam orbits, a deflection electromagnet for orbiting the charged particle beam along the circular orbit, and a stable region for betatron oscillation of the charged particle beam. By dividing the stable region of the betatron oscillation by displacing the region dividing means for dividing into a resonance region, the emitting means for extracting the charged particle beam from the circular orbit, and the central momentum of the charged particle beam, It is a circular accelerator provided with a momentum displacement control means for moving the charged particle beam to the resonance region of the betatron oscillation.

Further, according to the present invention, a duct containing a circular orbit around which the charged particle beam circulates, a deflection electromagnet for orbiting the charged particle beam along the circular orbit, and a betatron oscillation of the charged particle beam in a stable region. By dividing the stable region of the betatron oscillation by displacing the region dividing means for dividing into a resonance region, the emitting means for extracting the charged particle beam from the circular orbit, and the central momentum of the charged particle beam, A circular accelerator provided with a momentum displacement control means for moving the charged particle beam to the resonance region of the betatron oscillation, a transportation duct for transporting the charged particle beam, and a plurality of branch transportation ducts branched from the transportation duct. And switching means for switching the transportation of the charged particle beam from the transportation duct to each of the branched transportation ducts. A circular accelerator system comprising a radiation chamber for irradiating the charged particle beam transported by the branch transport duct.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. A circular accelerator having a charged particle beam emitting device according to Embodiment 1 of the present invention will be described below with reference to the drawings. In FIG. 1, 1
Is a deflecting electromagnet that orbits a charged particle beam along a circular orbit, and 2 is an outgoing sextupole electromagnet that forms a separatrix of betatron oscillation (that is, divides betatron oscillation into a stable region and a resonance region). 3 is a quadrupole electromagnet used for adjusting the betatron frequency and the area of the separatrix. In the present embodiment, the deflection electromagnet 1 displaces the central momentum of the charged particle beam with respect to the momentum uniquely determined from the reference magnetic field of the deflection electromagnet 1 to narrow the stable region of the betatron oscillation. Constitutes a momentum displacement control means for moving the to the resonance region of the betatron oscillation. Reference numeral 4 is an electrostatic electrode for extraction which becomes an entrance of an extraction channel (not shown) for extracting the charged particle beam from the circular orbit, 6 is a high frequency acceleration cavity for accelerating the charged particle beam, and 7 is used for adjusting chromaticity. It is a sextupole electromagnet.

FIG. 2 shows an operation pattern of the device used for emitting the charged particle beam. Reference numeral 8 denotes the magnetic field strength of the deflection electromagnet 1,
9 is the magnetic field strength of the extraction sextupole electromagnet 2, 10 is the magnetic field strength of the quadrupole electromagnet 3, 15 is the acceleration voltage of the high-frequency acceleration cavity 6, 1
6 is the magnetic field strength of the sextupole electromagnet 7. In addition, B0, B1, and B2 shown in FIG. 2 are points indicating changes in magnetic field strength,
The magnetic field strength 8 of the bending electromagnet 1 changes from B0 to B1,
Further, the direction changes to B2.

FIG. 3 shows a phase space at the position of the electrostatic electrode 4, 14 is an electrode gap of the electrostatic electrode 4, 17a is a separatrix when the magnetic field of the deflection electromagnet 1 is B0, and 17b.
Is a separatrix when the deflection magnetic field is B1, 18 is a path in which charged particles conforming to the resonance state approach the electrostatic electrode 4, 19
a is the center of the charged particle beam when the deflection magnetic field is B0 (reference magnetic field strength), 19b is the center of the charged particle beam when the deflection magnetic field is B1, and 19c is the center of the charged particle beam when the deflection magnetic field is B2. is there.

Next, the operation will be described. After the acceleration of the charged particle beam is completed, the acceleration voltage of the high-frequency acceleration cavity 6 is set to zero and the magnetic field strengths of the extraction hexapole electromagnet 2 and the quadrupole electromagnet 3 are adjusted so that the charged particle beam falls within the stable region of betatron oscillation. A separatorix 17a having a size that remains is formed.
The accelerating voltage is set to zero at the time of extraction so that the time structure of the acceleration frequency is not generated in the extracted charged particle beam.

After that, the magnetic field of the deflection electromagnet 1 is changed from B0 to B.
1 to form the separatrix 17b having an area equal to the emittance of the charged particle beam. At this time, since the center of the charged particle beam moves from the position 19a to the position 19b, it is not necessary to use the bump electromagnet 5 to bring the charged particle beam close to the electrostatic electrode 4. In the present embodiment, by generating a momentum dispersion function at least at the entrance of the exit channel, the orbit of the charged particle beam is synchronized with the deviation of the central momentum of the charged particle beam with respect to the deflection magnetic field when the charged particle beam is exited. And the distance between the emitting means and the emitting means.

When the magnetic field of the deflecting electromagnet 1 is further changed in the B2 direction, the separatrix moves in the direction of the position 19c while reducing its area. A charged particle with an emittance larger than the area of the separatrix causes a resonance of betatron oscillation and causes an electrode gap 1 along the path 18.
4, the charged particle beam can be emitted only by changing the magnetic field of the deflection electromagnet 1. As described above, in the present embodiment, the magnetic field of the deflection electromagnet 1 is changed while the frequency of the high-frequency acceleration cavity 6 is constant or the acceleration electric field is not generated in the high-frequency acceleration cavity 6, so that the charged particle beam with respect to the magnetic field is changed. Momentum excursions can be controlled.

The emission ends when the magnetic field of the deflecting electromagnet 1 becomes B2 and the area of the separatrix becomes zero. However, if the change of the magnetic field is reversed as shown by the dotted line in FIG. Therefore, the emission can be stopped midway without changing the magnetic field strength of the quadrupole electromagnet 3. That is, in the present embodiment, the emission direction of the charged particle beam is stopped by reversing the changing direction of the momentum excursion of the charged particle beam with respect to the magnetic field of the deflection electromagnet to widen the stable region of betatron oscillation.

Further, by setting the chromaticity appropriately by using the sextupole electromagnet 7 and matching the path 18 during the emission as shown in FIG. 3, the emittance of the emitted charged particle beam can be reduced. Therefore, it is not necessary to change the electric field strength of the electrostatic electrode 4.

As described above, in the present embodiment,
By using the deflection electromagnet 1 used for accelerating the charged particle beam, the central momentum of the charged particle beam is changed with respect to the momentum uniquely determined from the magnetic field of the deflection electromagnet. The circular orbit of the charged particle beam is brought closer to the exit channel without using, and at the same time, the stability region of the betatron oscillation is narrowed by using the chromaticity without changing the magnetic field of the quadrupole electromagnet 3, and the charged particle beam is emitted from the circular accelerator. It goes out. This eliminates the need for the bump electromagnet 5 and also eliminates the need for adding a function for changing the magnetic field of the quadrupole electromagnet 3, so that the manufacturing cost can be reduced and the device can be downsized. In addition, the exit of the charged particle beam is quickly stopped by reversing the direction of change in the momentum of the charged particle beam with respect to the deflection magnetic field, and moving the orbit away from the exit channel and simultaneously expanding the stable region of betatron oscillation. Therefore, since it is not necessary to add a function of quickly reversing the changing direction of the exciting current of the quadrupole electromagnet 3 to the power source or to separately install a quadrupole electromagnet that operates at high speed, the cost can be reduced accordingly. Further, the emittance of the emitted charged particle beam is adjusted by adjusting the chromaticity value using the sextupole electromagnet 7 so that the inclinations of the trajectories of the charged particles reaching the electrostatic electrode 4 are made uniform. It is easy to adjust and can emit a high-quality charged particle beam, and it is not necessary to add a pattern control function for changing the intensity of the electrostatic electrode 4 to the power source. Therefore, the manufacturing cost can be reduced and the apparatus can be downsized. Can be achieved.

Embodiment 2. FIG. 4 is an operation pattern of an apparatus used for emitting a charged particle beam, where 8 is the magnetic field strength of the deflection electromagnet 1, 9 is the magnetic field strength of the extraction hexapole electromagnet 2, and 1 is
0 is the magnetic field strength of the quadrupole electromagnet 3, 15 is the high frequency acceleration cavity 6
And 16 is the magnetic field strength of the sextupole electromagnet 7. Since the configuration of the device in this embodiment is basically the same as that shown in FIG. 1, the description thereof is omitted here.

In the first embodiment, the case where the acceleration voltage of the high frequency acceleration cavity 6 is set to zero when the charged particle beam is emitted has been described, but in the present embodiment, the acceleration voltage 15 is set as shown in FIG. To be generated continuously. Accordingly, when the emission is stopped halfway, the charged particle beam remaining in the circular accelerator can be decelerated and discarded promptly, and activation of the apparatus can be reduced.

Incidentally, in addition, in the case of the first embodiment, in order to decelerate the residual charged particle beam, it is necessary to capture the residual charged particle beam at a high frequency prior to the deceleration.

Embodiment 3. FIG. 5 is an operation pattern of an apparatus used for emitting a charged particle beam, where 8 is the magnetic field strength of the deflection electromagnet 1, 9 is the magnetic field strength of the extraction hexapole electromagnet 2, and 1 is
0 is the magnetic field strength of the quadrupole electromagnet 3, 20 is the high frequency acceleration cavity 6
And 16 is the magnetic field strength of the sextupole electromagnet 7.
Since the configuration of the device in this embodiment is basically the same as that shown in FIG. 1, the description thereof is omitted here.

In the second embodiment, the magnetic field of the deflecting electromagnet 1 is changed in order to deviate the momentum of the charged particle beam with respect to the reference magnetic field of the deflecting electromagnet 1, but in the present embodiment, FIG. As shown in, the acceleration frequency 20 of the high-frequency acceleration cavity 6 is changed while the deflection magnetic field 8 is constant to change the momentum of the charged particle beam. Since the change of the acceleration frequency and the response of the charged particle beam to the change are faster than the response speed of the magnetic field of the deflection electromagnet 1, the use of this means can shorten the period Tl and the period T2 of FIG. It is possible to start and stop the emission of the beam more quickly than in the second embodiment. Further, since it is not necessary to add a function to the electromagnet power source or to add an electromagnet, unlike the conventional method of stopping the emission of the charged particle beam using the quadrupole electromagnet, the cost and size of the accelerator can be reduced.

Fourth Embodiment FIG. 6 is an operation pattern of an apparatus used for emitting a charged particle beam, where 8 is the magnetic field strength of the deflection electromagnet 1, 9 is the magnetic field strength of the extraction hexapole electromagnet 2, and 1 is
0 is the magnetic field strength of the quadrupole electromagnet 3, 20 is the high frequency acceleration cavity 6
And 16 is the magnetic field strength of the sextupole electromagnet 7.
Since the configuration of the device in this embodiment is basically the same as that shown in FIG. 1, the description thereof is omitted here.

In the second embodiment, the magnetic field of the deflection electromagnet 1 is changed, and in the third embodiment, the momentum of the charged particle beam is changed by using the high-frequency acceleration cavity, so that the separation of the separatrix is achieved. Although the area has been reduced and the center of the charged particle beam has been moved, in the present embodiment, as shown in FIG. 6, preparation for extraction is performed until the area of the separatrix becomes equal to the emittance of the charged particle beam. And the start and stop of the extraction are performed by changing the acceleration frequency 20 of the high frequency acceleration cavity. That is, in this embodiment, the momentum excursion of the charged particle beam with respect to the deflection magnetic field is controlled by changing the frequency of the high-frequency acceleration cavity 6 and the magnetic field of the deflection electromagnet 1 simultaneously or sequentially. When the momentum dispersion function is small, the change width of the acceleration frequency is large in the third embodiment, but according to the present embodiment, the change width of the acceleration frequency 20 can be made small even with such a circular accelerator. It is possible to quickly start and stop the emission of the charged particle beam as in the third embodiment.

Embodiment 5. FIG. 7 is a phase space at the position of the electrostatic electrode 4, 14 is the electrode gap of the electrostatic electrode 4, 17a is the separation phase at the start of extraction (when the deflection magnetic field is Bl in the first embodiment), and 17b is the middle of extraction. Sepatrix (when the deflection magnetic field is B2 in the first embodiment),
Reference numeral 18 is a path through which charged particles in a resonance state approach the electrostatic electrode 4, 21 is a quadrangle representing the emittance of the emitted charged particle beam, 19a is the center of the charged particle beam at the start of emission, and 19b is an intermediate portion of the emission. It is the center of the charged particle beam.

In the first to fourth embodiments described above, the paths in which the charged particles in the resonance state approach the electrostatic electrode 4 are matched regardless of the momentum deviation of the charged particle beam. Is adjusted by adjusting the chromaticity value using the sextupole magnet 7 shown in FIG.
Is made different for each momentum excursion of the charged particle beam, and the emittance of the emitted charged particle beam is increased like a square 21. That is, the emittance of the charged particle beam emitted from the circular accelerator is adjusted by adjusting the relationship between the momentum excursion of the charged particle beam and the betatron frequency. By using this method, the ratio of the emittance in the horizontal direction and the emittance in the vertical direction of the emitted charged particle beam can be freely adjusted, so that the emittance in both directions suitable for beam scanning irradiation in a radiation medical system using the charged particle beam can be adjusted. Equal charged particle beams can be emitted.

[0041]

According to the present invention, a bending electromagnet for orbiting a charged particle beam along an orbit, an area dividing means for dividing the betatron oscillation of the charged particle beam into a stable area and a resonance area, and the charged particle beam To move the charged particle beam to the resonance region of the betatron oscillation by displacing the central momentum of the charged particle beam and narrowing the stable region of the betatron oscillation. Since it is a charged particle beam emitting device equipped with a momentum displacement control means, a bump electromagnet is not required, and at least that amount can be downsized and can be manufactured at low cost, and the stable region can be narrowed. Since the emission is adjusted, the emission can be easily adjusted and a high-quality charged particle beam can be emitted.

Further, by generating a momentum dispersion function at least at the entrance of the extraction means, the orbit of the charged particle beam is synchronized with the deviation of the central momentum of the charged particle beam with respect to the deflection magnetic field when the charged particle beam is emitted. Since the distance to the emitting means is changed, it is not necessary to use the bump electromagnet, so that it can be eliminated.

Further, since the changing direction of the momentum excursion of the charged particle beam with respect to the magnetic field of the deflection electromagnet is reversed to widen the stable region of the betatron oscillation, the extraction of the charged particle beam is stopped. Since it is not necessary to change the magnetic field strength of the electromagnet, means for changing the magnetic field strength can be eliminated.

Further, a high-frequency accelerating cavity for accelerating the charged particle beam is further provided, and the momentum of the charged particle beam is changed by changing the frequency of the high-frequency accelerating cavity while the magnetic field of the deflection electromagnet is constant. Since the momentum deviation is controlled, it is possible to quickly start and stop the emission of the charged particle beam.

Further, a high frequency accelerating cavity for accelerating the charged particle beam is further provided, and the magnetic field of the deflection electromagnet is changed while the frequency of the high frequency accelerating cavity is constant or an accelerating electric field is not generated in the high frequency accelerating cavity. Since the momentum excursion of the charged particle beam with respect to the magnetic field is controlled by the above, it is not necessary to change the frequency of the high frequency acceleration cavity and it is not necessary to generate an acceleration electric field in the high frequency acceleration cavity. It is possible to control the momentum deviation of the, and it is possible to easily control.

Further, a high frequency accelerating cavity for accelerating the charged particle beam is further provided, and the momentum of the charged particle beam with respect to the magnetic field is changed by simultaneously or sequentially changing the frequency of the high frequency accelerating cavity and the magnetic field of the deflection electromagnet. Since the deviation is controlled, the control can be easily performed.

Since the relation between the momentum excursion of the charged particle beam and the betatron frequency is adjusted to adjust the emittance of the charged particle beam emitted from the emitting means, the electrostatic electrode It is not necessary to change the electric field strength.

Further, according to the present invention, a duct including a circular orbit around which the charged particle beam orbits, a deflection electromagnet for orbiting the charged particle beam along the circular orbit, and a stable region for betatron oscillation of the charged particle beam. By dividing the stable region of the betatron oscillation by displacing the region dividing means for dividing into a resonance region, the emitting means for extracting the charged particle beam from the circular orbit, and the central momentum of the charged particle beam, Since the charged particle beam is provided with the momentum displacement control means for moving the charged particle beam to the resonance region of the betatron oscillation, it is possible to obtain a circular accelerator whose emission can be easily adjusted.

Further, according to the present invention, a duct including a circular orbit around which the charged particle beam orbits, a deflection electromagnet for orbiting the charged particle beam along the circular orbit, and a betatron oscillation of the charged particle beam in a stable region. By dividing the stable region of the betatron oscillation by displacing the region dividing means for dividing into a resonance region, the emitting means for extracting the charged particle beam from the circular orbit, and the central momentum of the charged particle beam, A circular accelerator provided with a momentum displacement control means for moving the charged particle beam to the resonance region of the betatron oscillation, a transportation duct for transporting the charged particle beam, and a plurality of branch transportation ducts branched from the transportation duct. And switching means for switching the transportation of the charged particle beam from the transportation duct to each of the branched transportation ducts. , Since a radiation chamber for irradiating the charged particle beam transported by the branch transport duct, it is possible to adjust the emission obtained easily circular accelerator system.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a configuration of a circular accelerator having a charged particle beam emitting device of the present invention.

FIG. 2 is an explanatory diagram showing an operation pattern of the emitting device according to the first embodiment of the present invention.

FIG. 3 is an explanatory diagram showing the separarix of 1/3 integer resonance according to the first embodiment of the present invention.

FIG. 4 is an explanatory diagram showing an operation pattern of the emission device according to the second embodiment of the present invention.

FIG. 5 is an explanatory diagram showing an operation pattern of the emission device according to the third embodiment of the present invention.

FIG. 6 is an explanatory diagram showing an operation pattern of the emitting device according to the fourth embodiment of the present invention.

FIG. 7 is an explanatory diagram showing a separarix of 1/3 integer resonance according to the fifth embodiment of the present invention.

FIG. 8 is a configuration diagram showing a configuration of a conventional charged particle beam emitting device (circular accelerator).

FIG. 9 is an explanatory diagram showing an operation pattern of a conventional charged particle beam emission device.

FIG. 10 is an explanatory diagram showing a separarix of 1/3 integer resonance of a conventional charged particle beam emitting device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1,101 Bending electromagnet, 2,102 Emission hexapole electromagnet, 3,103 Quadrupole electromagnet, 4,104 Emission electrostatic electrode, 5,105 Emission bump electromagnet, 6,106
High-frequency acceleration cavity, 7,107 hexapole electromagnet, 8,108
Excitation pattern of deflection electromagnet, 9,109 Excitation pattern of hexapole electromagnet for extraction, 10,110 Excitation pattern of quadrupole electromagnet, 11,111 Electric field application pattern of electrostatic electrode for extraction, 12,112 Excitation pattern of bump electromagnet for emission , 14, 114 Gap of electrostatic electrode for emission, 15
Acceleration voltage pattern of high-frequency acceleration cavity, 16 Excitation pattern of hexapole electromagnet, 17 Separatrix, 18 Movement path of emitted charged particles, 19 Center of charged particle beam, 20 Frequency pattern of high-frequency acceleration cavity, 21 Emitted Emittance of charged particle beam, 113a, 1
13b Conventional Separatrix.

Claims (9)

[Claims] 1. A deflection electromagnet for orbiting a charged particle beam along a circular orbit, a region dividing means for dividing betatron oscillation of the charged particle beam into a stable region and a resonance region, and the charged particle beam for the circular orbit. Extraction means for extracting the charged particle beam from the extraction means, and displacement of the central momentum of the charged particle beam to narrow the stable region of the betatron oscillation, thereby controlling the momentum displacement to move the charged particle beam to the resonance region of the betatron oscillation. And a means for emitting the charged particle beam. 2. A circular orbit of the charged particle beam in synchronization with the deviation of the central momentum of the charged particle beam with respect to the deflection magnetic field when the charged particle beam is emitted by generating a momentum dispersion function at least at the entrance of the emitting means. The distance between the emitting means and the emitting means is changed.
The charged particle beam emitting device according to. 3. The emission of the charged particle beam is stopped by reversing the changing direction of the momentum excursion of the charged particle beam with respect to the magnetic field of the deflecting electromagnet to widen the stable region of betatron oscillation. Item 1 or 2
The charged particle beam emitting device according to. 4. A high-frequency accelerating cavity for accelerating the charged particle beam is further provided, and the frequency of the high-frequency accelerating cavity is changed to change the momentum of the charged particle beam while the magnetic field of the deflection electromagnet is constant. 4. The charged particle beam emitting apparatus according to claim 1, wherein the momentum excursion is controlled. 5. A high frequency accelerating cavity for accelerating the charged particle beam is further provided, and the magnetic field of the deflection electromagnet is changed while the frequency of the high frequency accelerating cavity is constant or an accelerating electric field is not generated in the high frequency accelerating cavity. 4. The charged particle beam emission device according to claim 1, wherein the momentum deviation of the charged particle beam with respect to the magnetic field is controlled by. 6. A momentum of the charged particle beam with respect to the magnetic field, further comprising: a high frequency accelerating cavity for accelerating the charged particle beam, wherein the frequency of the high frequency accelerating cavity and the magnetic field of the deflection electromagnet are simultaneously or sequentially changed. The charged particle beam emitting apparatus according to claim 1, wherein the deviation is controlled. 7. The emittance of the charged particle beam emitted from the emitting means is adjusted by adjusting the relationship between the momentum excursion of the charged particle beam and the betatron frequency. 6. The charged particle beam emitting device according to item 6. 8. A duct including a circular orbit around which a charged particle beam circulates, a deflection electromagnet that orbits the charged particle beam along the circular orbit, and betatron oscillation of the charged particle beam into a stable region and a resonance region. Region dividing means for dividing, emitting means for extracting the charged particle beam from the orbit, and displacing the central momentum of the charged particle beam to narrow the stable region of the betatron oscillation, thereby the charged particle beam A circular accelerator comprising: a momentum displacement control means for moving the betatron to the resonance region of the betatron oscillation. 9. A duct that encloses a circular orbit around which a charged particle beam circulates, a deflection electromagnet that orbits the charged particle beam along the circular orbit, and betatron oscillation of the charged particle beam into a stable region and a resonance region. Region dividing means for dividing, emitting means for extracting the charged particle beam from the orbit, and displacing the central momentum of the charged particle beam to narrow the stable region of the betatron oscillation, thereby the charged particle beam A circular accelerator having a momentum displacement control means for moving the betatron oscillation to the resonance region, a transport duct for transporting the charged particle beam, a plurality of branch transport ducts branched from the transport duct, and the transport Switching means for switching transportation of the charged particle beam from the duct to each of the branch transportation ducts; Circular accelerator system characterized by comprising an irradiation chamber for irradiating the charged particle beam transported by a duct.