JPH11176596A - Charged particle beam equipment - Google Patents

Abstract

(57) [Summary] [PROBLEMS] Even if the inclination of a beam changes at the entrance of an output deflector, this is corrected to maintain a constant beam trajectory in the beam transport system, and to maintain a large current over the entire period of beam extraction. The purpose is to realize a synchrotron that can extract a beam. A second object is to reduce restrictions on the design and operation of the synchrotron main body required to achieve the above object. SOLUTION: In a charged particle beam apparatus including a synchrotron which emits a charged beam through a deflector for extraction by resonance extraction through resonance and a beam transport system for transporting the emitted beam, an entrance of the deflector for extraction within an output beam pulse is provided. An output deflector for changing the magnetic field or electric field intensity in accordance with the temporal change of the output angle of the light source, and one or more units installed in a beam transport system for changing the magnetic field or electric field intensity in synchronization with the output deflector Trajectory correction deflecting device.

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 apparatus for accelerating a particle beam such as a proton beam to high energy and irradiating a human body with the beam to destroy a cancer tissue or the like.

[0002]

2. Description of the Related Art FIG. 6 is a plan view of a conventional synchrotron disclosed in, for example, Japanese Patent Laid-Open No. 5-109499.
FIG. 7 is a phase space between the initial stage and the final stage of emission at the entrance of the deflector for emission in FIG. 6 at the time of third-order resonance excitation emission. The horizontal axis is the horizontal displacement x of the charged particle beam, and the vertical axis is the orbital gradient x of the beam. It is a figure showing '(= dx / ds, s is a distance in the traveling direction). FIG. 8 is an enlarged view of the vicinity of the deflector for emission and a diagram showing a bump orbit.

In FIG. 6, 1 is an equilibrium orbit (center orbit) of particles orbiting a synchrotron, 3 is a deflection electromagnet for deflecting particles, 5 is a quadrupole electromagnet for converging particles, 7 is an acceleration device, and 9 is resonance extraction. The hexapole electromagnets 10 and 11 used for the resonance excitation are used to shift a part of the equilibrium trajectory toward the deflecting device 13 at the time of emission, the bump electromagnet 12 is a shifted equilibrium orbit, and 13 is a particle. Deflecting device for deflecting light and taking it out of the synchrotron, 14
Is a tune correcting quadrupole electromagnet for gradually bringing the tune closer to an integer ± 1/3 at the time of emission, and 15 is an incident inflector.

Next, the operation will be described. Bending electromagnet 3
And the effect of the quadrupole electromagnet 5, the incidence inflector 15
Charged particles incident from the orbit stably oscillate around the equilibrium orbit 1 (a closed loop in which the charged particles can stably move) with betatron oscillation. Also,
When passing through the acceleration cavity 7, the charged particles are energized. In such an acceleration process, the tune of the charged particles, that is, the betatron frequency per cycle of the accelerator, is
Using a quadrupole electromagnet, both horizontal and vertical directions are usually integers ±
It is set to 1/4.

After the acceleration, at the stage of emitting a beam as a collection of charged particles, the quadrupole electromagnet 5 shown in FIG. To extract the horizontal tune and the beam in the vertical direction, adjust the vertical tune as follows. That is, in the case of half-integer resonance, the tune is approximated to the integer ± １ ／, and in the case of the tertiary resonance, the tune is approximated to the integer ± １ ／. In this situation, to excite half-integer resonance, an octupole electromagnet provided in advance in the accelerator is excited, and to excite tertiary resonance, a hexapole electromagnet is excited (FIG. Is shown). From the above,
Particles whose resonance is excited by the betatron oscillation and exceed the stability limit have a large change in the betatron oscillation.
In order to prevent the beam from colliding with the duct and being lost in this situation, the two-pole bump electromagnets 10 and 11 shown in FIGS. A bump trajectory 12 (a trajectory locally distorted) is shifted to the side of the deflecting device.

The behavior of the beam at this time will be described with reference to the phase space of FIG. FIG. 7 shows the phase space at the beginning and end of the emission at the entrance of the emission deflector in FIG. 6 at the time of emission of the tertiary resonance excitation. The horizontal axis is the horizontal displacement x of the beam, and the vertical axis is the orbital gradient x ′ ( = Dx / ds, where s is the distance in the traveling direction). At the time of the tertiary resonance excitation, there is a triangular separatrix (stability limit) like ΔABC in FIG. In the case of the tertiary resonance, the tune is almost an integer ± １ ／, so that the state is almost the same once every three times around the beam. That is,
Each charged particle can take three states at the emission position. The three flows indicated by black circles in FIG. 7 show transitions of the three states of the charged particles outside the separatrix. For example, in FIG. 7A, the charged particle in the state of a1 is b1 after one round, c1 after one round, or a2, b2,
.., and finally reaches xd beyond the electrode of the emission deflector which is the emission device, and is taken out.

Some orbiting charged particles have large and small amplitudes of betatron oscillation. In order to gradually emit the charged particles, the charged particles are taken out in order from the one having the larger amplitude of the betatron oscillation. For this reason, the separatrix is made relatively large in the initial stage of the emission as shown in FIG. 7A, and thereafter reduced with time. This operation is performed using the auxiliary quadrupole electromagnet 14 shown in FIG. That is, the tune is further approximated to an integer ± チ ュ ー by the auxiliary quadrupole electromagnet 14 to reduce the separatrix to ΔA′B′C ′ in FIG. 7 so as to emit a beam.

However, as can be seen from FIG. 7, the inclination of the beam changes at the entrance of the deflector for emission due to the change in the magnitude of the separatrix. In this case, the position of the output beam fluctuates with time in the beam transport system (system from the output deflector to the position where the beam is used).
The beam position will also change at the last target position.

In order to correct this, not only is the bump electromagnet used to simply shift the beam to the exit deflecting device side, but also to correct the variation in the tilt of the beam at the entrance of the exit deflecting device. Also use. Although only two bump electromagnets are used in the example of FIG. 6, in this case, the phase advance of the betatron oscillation between the two bump electromagnets is π.
And the inclination of the bump trajectory at the entrance of the output deflector is limited, so that the installation position of the bump electromagnet and the synchrotron design are restricted.

[0010]

In the above-mentioned conventional method for correcting the inclination of the beam that changes at the entrance of the deflector for extraction during beam extraction, the conventional method for properly installing a bump electromagnet in the design of a synchrotron is described. There is a problem that it is greatly restricted. Further, there is a problem that a small synchrotron cannot be applied due to space restrictions. Further, according to this conventional technique, a change in the tilt of the beam can be reduced, but a complete correction cannot be made. On the other hand, the equilibrium orbit is distorted in a normal synchrotron due to an installation error of the bending electromagnet 3 or the quadrupole electromagnet 5, but if the equilibrium orbit after acceleration is distorted, it is necessary to set the magnetic field of the bump electromagnet and change with time in consideration of the distortion. . Since it is difficult to accurately measure the distortion of the equilibrium orbit, there is also a problem that optimization of the bump electromagnet becomes very difficult.

The present invention has been made to solve the above-mentioned problems of the prior art. Even if the inclination of the beam changes at the entrance of the output deflector, it is corrected and corrected in the beam transport system. An object of the present invention is to realize a synchrotron capable of extracting a beam with a large current over the entire beam extraction period while maintaining a constant beam trajectory. A second object is to reduce restrictions on the design and operation of the synchrotron main body required to achieve the above object.

[0012]

According to a first aspect of the present invention, there is provided a charged particle beam apparatus comprising: a synchrotron for accelerating a charged beam and emitting through a deflector for extraction by resonance extraction; and a beam transport for transporting the output beam. In a charged particle beam apparatus comprising a system, an output deflector for changing a magnetic field or an electric field intensity in accordance with a temporal change of an output angle at an input of the output deflector in an output beam pulse, and the output deflector are synchronized with the output deflector. And one or more orbit correction deflecting devices installed in the beam transport system for changing the magnetic field or electric field strength.

In the charged particle beam apparatus according to the second configuration of the present invention, a part of the trajectory correcting / deflecting device is installed at a position where the charged particle beam exiting the exiting deflecting device crosses the central orbit.

In a charged particle beam apparatus according to a third aspect of the present invention, the trajectory correcting / deflecting apparatus is installed between the exiting deflection apparatus and the first focusing or deflection apparatus of the beam transport system.

According to a fourth aspect of the present invention, there is provided a charged particle beam apparatus comprising: a synchrotron which accelerates a charged beam and emits through a deflector for extraction by resonance extraction and a beam transport system for transporting the output beam. In the apparatus, the beam transport system includes a plurality of trajectory correcting / deflecting devices for changing the magnetic field or the electric field strength in accordance with the temporal change of the output angle at the entrance of the output deflection device in the output beam pulse.

In a charged particle beam apparatus according to a fifth aspect of the present invention, a plurality of trajectory correcting / deflecting apparatuses are provided between the exiting / deflecting apparatus and the first focusing or deflecting apparatus of the beam transport system.

A charged particle beam apparatus according to a sixth aspect of the present invention is a charged particle beam comprising a synchrotron which accelerates a charged beam and emits through a deflector for extraction by resonance extraction and a beam transport system for transporting the output beam. In the apparatus, one or more orbit correction deflecting devices that change the magnetic field or electric field strength in accordance with the temporal change of the output angle at the entrance of the output deflecting device in the output beam pulse, and the phase of the betatron oscillation is used for output. Nπ from the deflector entrance
(N is an integer).

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a plan view of a synchrotron according to a first embodiment of the present invention, and FIG. 2 is an enlarged view near an emission part of the synchrotron and a diagram showing a beam orbit. FIG. 3 is a diagram showing an example of a change in output of each device with respect to the extracted beam.

1 and 2, reference numeral 1 denotes an equilibrium trajectory (center trajectory) of particles orbiting a synchrotron, 3 denotes a deflection electromagnet for deflecting particles, 5 denotes a quadrupole electromagnet for converging particles,
7 is an accelerating device, 9 is a hexapole electromagnet for resonance excitation used for resonance extraction, 10 and 11 are bump electromagnets for shifting a part of the equilibrium orbit to the deflector 13 for emission, 12
A bump orbit, which is a shifted equilibrium orbit, 13 is an emission deflector for deflecting particles and taking it out of the synchrotron, 14 is a tune-correcting quadrupole electromagnet for gradually bringing the tune closer to an integer ± 1/3 at the time of emission. , 15 is an incident inflector, 17 is a central orbit of a beam transport system, 20 is an orbit correcting and deflecting device whose magnetic field changes with time in accordance with an outgoing beam, 22 is a power supply of an outgoing deflector, and 24 is an orbit correcting and deflecting device. A power supply for the device, 26 is a waveform shaping device for determining the output waveform of each of the power sources 22 and 24, 28 is a control computer for arbitrarily creating a waveform, and 30 is a trigger at the start of emission to start the output of the waveform shaping device. It is a trigger generator.

Next, the operation will be described. The synchrotron and the resonance extraction therefrom are as described in the conventional example. Here, a description will be given after the particles reach the entrance of the output deflection device 13 due to resonance. Some deflectors for emission deflect particles by a magnetic field, while others deflect them by an electric field. Here, a deflecting device using a magnetic field is used. In some high-energy devices, the output deflection device may be divided into a plurality of devices. When the phase space coordinates of the charged particles at the entrance of the output deflector are represented by x ₀ and x ′ ₀ ,
The particle coordinates x1, x'1 at the exit are given by the following equations. x ₁ = cos φ ・ x ₀ + ρ sin φ ・ x ' ₀ + ρ ( ₁ -cos φ) ΔP ₀ / P ₀ (1) x' ₁ =-sinφ / ρ ・ x ₀ + cosφ ・ x ' ₀ + sinφ ・ ΔP ₀ / P ₀ (2) Here, ΔP ₀ / P ₀ represents the error of the momentum of the particle, and the particle adds the particle having the zero momentum error to the magnetic field intensity of the output deflector by −ΔP ₀ / It is equivalent to the one changed by P ₀ .
That is, the trajectory of the particles having a high momentum by 1% in the deflector for emission and the magnetic field strength are set to 1 for particles having a zero momentum error.
The trajectory at the time of the decrease is the same. φ is the deflection angle of the output deflector, and ρ is the radius of curvature.

In the resonance extraction, x ₀ and x ′ ₀ temporally change during the extraction as described in the conventional example. Here, the variation of x ₀ is the correction is not considered because it is random. Therefore, x ₀ = 0. At this time, x ₁ = ρ sin φ x ' ₀ + ρ (1-cos φ) ΔP ₀ / P ₀ (3) x' ₁ = cos φ x ' ₀ + sin φ ΔP ₀ / P ₀ (4) Deflection device for emission The trajectory correction deflection device 20 is installed at a position L away from the exit. In the meantime, assuming that there is no focusing and deflecting element, the particle coordinate x ₂ at the position of the orbit correction deflector,
x ' ₂ is as follows. x ₂ = x ₁ + Lx ' ₁ (5) x' ₂ = x ' ₁ (6)

In order for particles to travel on the central trajectory downstream of the trajectory correction deflecting device, x ₂ = 0 at the position of the trajectory correction deflecting device, and a kick angle of -x'1 by the trajectory correcting deflecting device. Should be given. In this _{case, 0 = x 1 + L ·} x '1 (7) _{Accordingly, ρsinφ · x' 0 + ρ} (1 - cosφ) ΔP 0 / P 0 = -L (cosφ · x '0 + sinφ · ΔP 0 / P ₀ ) (8) (ρ sin φ + L cos φ) x ' ₀ =-(ρ (1-cos φ) + L sin φ) ΔP ₀ / P ₀ (9) All the values in parentheses in the above equation are constants. Therefore, the code in the magnetic field strength in proportion to the change in _{x '0 ΔP 0 / P 0} ( for extraction deflecting device is reversed. For example the magnetic field intensity of the outgoing deflection apparatus when [Delta] P ₀ / P ₀ is + 1% Lower by 1%, and increase by 1% when the value is -1%). That is, the beam by the particle at the position of all the x _'0 with respect to the beam transport system of the track correcting deflector solution exists across the center trajectory, the inclination of the particle changes by the exit deflection device entrance in the beam extraction Beam orbit fluctuations in the transport system can be corrected. Is manner of change in the trajectory correction deflection device can be determined from x _'1 shown in Equation (4).

Here, the trajectory correcting / deflecting device has x in it.
The displacement was negligible and a thin lens approximation was made. Since the change in x ′ ₀ is obtained by a beam simulation by a computer at the time of design, it is known in advance how the magnetic field strength of the output deflector must be temporally changed. Of course, finally, through experiments using beams,
The temporal change may be optimized.

FIG. 2 shows an example of the beam trajectory, where x ′ ₀ = 0
Output deflector 1 so that the particles pass through the central orbit 17
When a magnetic field strength of 3 is set, a particle having a certain value x ′ ₀ is drawn out in a trajectory like 18. At this time, if the magnetic field strength is increased by the absolute value of ΔP ₀ / P ₀ given by the equation (9), the trajectory becomes like 19, and the trajectory correction deflecting device 2
Cross the center trajectory at 0. Then, if deflected by the orbit correction deflection device -x 'by _1, the particles on the downstream side of the orbit correction deflection device is advanced over the center trajectory.

When the momentum of the beam changes during the extraction, the change may be considered in ΔP ₀ / P ₀ in the above equation. In addition, although the single deflector 13 for output is used, in the case of a high-energy synchrotron, it may be difficult to obtain a predetermined deflection angle with one deflector. May be mixed. Even in this case, the same effect can be obtained, and the number of devices that change the magnetic field with time may be all, the first device, or a plurality of devices including the first device. An optimal method may be selected according to the synchrotron.

FIG. 1 shows an example of a hardware configuration for changing the magnetic field strengths of the output deflection device 13 and the trajectory correction deflection device 20 in time synchronization. FIG. 3 shows an example of the temporal change of the magnetic field intensity. The uppermost part of FIG. 3 shows the extracted beam intensity. For example, the beam that goes around the synchrotron for 500 ms is gradually extracted. Meanwhile, the inclination of the particles at the entrance of the exit deflector changes,
For example, assume that a change is made as shown in the second row from the top in FIG. Although it is changed linearly in the figure, it does not always change linearly in actuality. In addition, although the variation is only on the plus side, the variation may be from the minus side to the plus side.

The diagram below shows how the field strength of the exit deflector is required to cause the particles to cross the central orbit at the location of the orbit correction deflector 20 in the beam transport system. The bottom row shows how to change the magnetic field strength of the trajectory correction deflection device. In this example, since the inclination of the beam at the entrance of the output deflection device does not become zero, the magnetic field of the trajectory correction deflection device also changes from a certain value other than zero.

In FIG. 3, the intensity of the magnetic field of the deflecting device for trajectory and the orbit correcting deflecting device rises sharply at the start of beam emission. However, when the deflecting device for emission is an electromagnet, such rising is difficult and more slowly. It becomes a rising. The beam is accelerated for several hundred ms, then extracted, and accelerated again for several hundred ms after the extraction is completed. Therefore, it is not necessary to make these devices rise and fall quickly.

The power supplies 22 and 24 of the deflector for emission and the orbit correction deflector are, for example, power supplies for outputting an output current proportional to the input voltage. The waveform shaping device 26 is a device that outputs a voltage from a waveform pattern stored in a memory, for example, when a signal from the trigger generator 30 is received. Therefore, when a signal is output from the trigger generator at a required timing, the waveform patterns stored in the respective waveform shaping devices are output as currents from the respective power supplies, and a magnetic field as shown in FIG. 3 is obtained. These waveform patterns are stored in the control computer 2
8 can be changed freely, and the waveform is optimized through beam experiments.

If this method is used, a bump electromagnet for bringing the equilibrium trajectory closer to the output deflector is required as in the conventional example, but it is necessary to create a bump trajectory that makes the beam inclination constant at the entrance of the output deflector. However, the constraints in the synchrotron design can be minimized, and a more effective synchrotron can be designed. Also, even if the beam tilt at the entrance of the output deflector is different from the calculation due to the distortion of the equilibrium orbit after acceleration, the balanced orbit is optimized by optimizing the magnetic fields of the output deflector and the orbit correction deflector through beam experiments. Since the influence of the distortion can be corrected, there is an effect that the distortion of the equilibrium orbit can be allowed.

Embodiment 2 In the above-described embodiment, the output deflector 13 is not an electromagnet that provides a divergent function at the end portion, but is a deflector for output that provides a divergent function at the end portion. Even so, the same effect can be obtained. In this case, the magnetic field changes of the output deflection device and the trajectory correction deflection device are different from the above-mentioned equations, and are calculated in consideration of the divergence effect. In general, an output deflector has an edge angle when formed in a simple manner. However, a system that allows the converging / diverging effect by this can provide an inexpensive device.

Embodiment 3 In the above-described embodiment, there is no device for focusing and deflecting between the output deflecting device 13 and the trajectory correcting deflecting device 20. Similar effects can be obtained. Also in this case, similar to the second embodiment,
The magnetic field change of the deflecting device for emission and the orbit correcting deflecting device is determined in consideration of the influence of these devices on the beam. Thereby, there is an advantage that there is no restriction on the design of the beam transport system, and a more effective design of the beam transport system becomes possible.

Fourth Embodiment FIG. 4 is a diagram showing a method of correcting a temporal variation of a beam position without changing the magnetic field intensity of the deflecting device 13 for emission. Two trajectory correction devices 20 are arranged in the beam transport system (system between the deflecting device for emission and the beam use position), and are deflected by the first trajectory correction deflecting device so as to cross the central trajectory 17 downstream thereof. Then, the beam is deflected so as to be parallel to the central trajectory by a second trajectory correcting / deflecting device arranged at a position crossing the central trajectory. As a result, the beam travels on the central orbit downstream of the second orbit correction deflecting device.

How to change the trajectory correcting / deflecting device in this case will be considered. The distance from the exit of the emission deflecting device to the first orbit correction deflecting device is L1, and the distance between the first and second trajectory correcting and deflecting devices is L2. The beam coordinates at the exit of the exit deflector are given by equations (3) and (4).
Since the magnetic field of the output deflector is constant and the momentum change of the beam is not considered, the position and inclination _xf , x of the beam at the entrance of the first orbit correction deflector are not considered. beam position and tilt x _f in the entrance, x _'f is given as follows. x _f = ρsinφ x ' ₀ + L1 x x _f (10) x' _f = x ' ₁ = cos φ x' ₀ (11)

[0035] When the inclination of the beam by one eye orbit correction deflection device outlet x 'and _f0, in order to cross the center trajectory 17 at the position of the track correcting deflection apparatus beams are two cars th, 0 = ρsinφ · x ' ₀ + L1 ・ cosφ ・ x' ₀ + L2 ・ x ' _f0 x' _f0 = ー (ρsinφ + L1 ・ cosφ) x ' ₀ / L2 (12) Here, x displacement in the orbit correction / deflection device is Ignored as small. In the second orbit correction deflecting device, if a deflection angle of -x ' _f0 is given to the beam, the beam advances on the central trajectory on the downstream side. x _'0 is the deflection angle x of the two single eye orbit correction deflection device for time varying' _f0 also be time varying.
The deflection angle of the first orbit correction deflecting device is given by the following equation. x ' _f -x' _f0 = (cosφ + (ρsinφ + L1 ・ cosφ) / L2) x ' ₀ (13)

In this method, it is not necessary to change the output deflection device 13 which is generally designed with a large current and a strong magnetic field over time, so that the design and manufacture of the output deflection device are facilitated.

Fifth Embodiment In the above-described embodiment, no device for providing a focusing and deflecting action is provided between the output deflector 13 and the trajectory correction deflector 20. Similar effects can be obtained. Also in this case, similar to the second embodiment,
The magnetic field change of the deflecting device for emission and the orbit correcting deflecting device is determined in consideration of the influence of these devices on the beam. Thereby, there is an advantage that there is no restriction on the design of the beam transport system, and a more effective design of the beam transport system becomes possible.

Embodiment 6 FIG. 5 shows the trajectory correcting deflecting device 2 at a position where the advance of the phase of the betatron oscillation has advanced by π from the entrance of the deflecting device 13 for emission.
FIG. 9 is a diagram illustrating an example of correcting a change in a trajectory by arranging 0s. In the beam transport system, generally, a quadrupole electromagnet 5 for focusing the beam and a bending electromagnet 3 for guiding the beam to a required place are appropriately arranged. In FIG. 5, the bending electromagnet is omitted. In such an arrangement of the electromagnets, the beam having a certain angle with respect to the central trajectory at the entrance of the output deflector travels while vibrating around the central trajectory. This is called betatron oscillation.

The phase advance of this vibration is nπ (n is an integer)
At a distance only, all beams at an angle to the central trajectory at the entrance of the exit deflector traverse the central trajectory.
The crossing angle is proportional to the angle at the entrance of the output deflector. Therefore, if the orbit correction deflecting device 20 is arranged at a position crossing the center trajectory and the magnetic field intensity of the orbit correction deflecting device is changed in accordance with a change in the angle of the beam at the entrance of the output deflector, the beam will be centered on the downstream side. Go on orbit. The required deflection angle of the trajectory correction deflecting device differs depending on the arrangement of the quadrupole electromagnet and the deflection electromagnet, but can be easily calculated once the arrangement is determined. Here, it was assumed that the X-displacement at the entrance of the output deflector was ignored, and the beam was on the central orbit and did not change with time.

In this method, the position (inclination) of the output beam
Since at least one device is required for correcting the fluctuation, the cost can be reduced.

[0041]

According to the charged particle beam apparatus according to the first, second and third constructions of the present invention, the synchrotron and the output beam accelerated by the charged beam and output through the output deflector by resonance extraction. In a charged particle beam apparatus including a beam transport system for transporting, an output deflector for changing a magnetic field or an electric field intensity in accordance with a temporal change of an output angle at an input of the output deflector in an output beam pulse; Since one or more orbit correction deflecting devices are installed in the beam transport system that changes the magnetic field or electric field intensity in synchronization with the device, the inclination of the beam at the entrance of the deflecting device for emission changes. By correcting this, the beam trajectory in the beam transport system can be kept constant, and a large current can be extracted over the entire period of beam extraction. Further, since the change in the tilt of the beam at the entrance of the output deflector can be tolerated, there are few restrictions on the design and operation of the synchrotron main body, and no increase in size is required.

According to the charged particle beam apparatus according to the fourth and fifth configurations of the present invention, a synchrotron for accelerating the charged beam and emitting through the emission deflection device by resonance extraction and a beam transport system for transporting the output beam. In the charged particle beam apparatus, the beam transport system has a plurality of trajectory correcting / deflecting apparatuses for changing the magnetic field or electric field strength in accordance with the temporal change of the exit angle at the entrance of the exit deflection apparatus in the exit beam pulse. Therefore, in addition to the effects of the first to third configurations, there is no restriction on the design and operation of the output deflector requiring a large current,
The beam trajectory in the beam transport system can be kept constant by only the trajectory correction deflection device.

According to the charged particle beam apparatus according to the sixth aspect of the present invention, the charged beam is constituted by a synchrotron which accelerates the charged beam and emits it through the output deflector by resonance extraction and a beam transport system which transports the output beam. In a particle beam device, one or more orbit correction deflecting devices that change the magnetic field or electric field strength in accordance with the temporal change in the output angle at the entrance of the output deflecting device in the output beam pulse are controlled by the phase of the betatron oscillation. Since it is installed at a position advanced by nπ (n is an integer) from the entrance of the output deflector, in addition to the effects of the first to third configurations, it is possible to design and operate the output deflector requiring a large current. There is no restriction, and the configuration of the trajectory deflection device is simplified.

[Brief description of the drawings]

FIG. 1 is a plan view of a synchrotron according to a first embodiment of the present invention.

FIG. 2 is an enlarged view near an emission part of a synchrotron and a diagram illustrating a beam trajectory.

FIG. 3 is a diagram illustrating an example of a change in output of each device with respect to an extracted beam.

FIG. 4 is a diagram showing a method of correcting a temporal variation of a beam position without changing the magnetic field intensity of the output deflection device 13;

FIG. 5 is a diagram illustrating an example in which the trajectory correction deflecting device 20 is disposed at a position where the phase of the betatron oscillation advances π from the entrance of the output deflector 13 to correct the change in the trajectory.

FIG. 6 is a plan view of a conventional synchrotron.

FIG. 7 is a diagram showing a phase space at the initial stage and the final stage at the time of tertiary resonance excitation emission.

FIG. 8 is an enlarged view of the vicinity of an emission deflection device and a diagram illustrating a bump orbit.

[Explanation of symbols]

1 equilibrium orbit (center orbit), 3 bending electromagnet, 5 quadrupole electromagnet, 7 accelerator, 9 hexapole electromagnet for resonance excitation, 1
0,11 Bump electromagnet, 12 Bump orbit, 13 Emission deflection device, 14 Tune correction quadrupole electromagnet, 15
Incident inflector, 17 center trajectory, 20 trajectory correcting / deflecting device, 22 power source for emitting deflecting device, 24 power source for trajectory correcting / deflecting device, 26 waveform shaping device, 28 control calculator, 30 trigger generator.

Claims (6)

[Claims] 1. A charged particle beam apparatus comprising a synchrotron which emits a charged beam through a deflector for extraction by resonance extraction through resonance and a beam transport system for transporting the output beam, an entrance of the deflector for output within a pulse of the output beam. An output deflector for changing the intensity of a magnetic field or an electric field in accordance with a temporal change of an output angle at one time, and one or more devices installed in a beam transport system for changing the intensity of a magnetic field or an electric field in synchronization with the output deflector A charged particle beam device, comprising: a trajectory correction deflection device. 2. The charged particle beam apparatus according to claim 1, wherein a part of the trajectory correcting / deflecting device is installed at a position where the charged particle beam exiting the emission deflecting device crosses the central orbit. 3. The charged particle beam apparatus according to claim 2, wherein the trajectory correction deflecting device is installed between the exit deflecting device and the first focusing or deflecting device of the beam transport system. 4. A charged particle beam apparatus comprising a synchrotron which emits a charged beam through a deflecting device for extraction by resonance extraction through resonance and a beam transport system for transporting the emitted beam, the entrance of the deflecting device for emission within an output beam pulse. A charged particle beam apparatus comprising a plurality of trajectory correcting / deflecting devices for changing a magnetic field or an electric field intensity in accordance with a temporal change of an emission angle in a beam transport system. 5. The charged particle beam apparatus according to claim 4, wherein a plurality of trajectory correcting / deflecting apparatuses are provided between the deflecting apparatus for output and the first focusing or deflecting apparatus of the beam transport system. 6. A charged particle beam device comprising a synchrotron which emits a charged beam through a deflector for extraction by resonance extraction through resonance and a beam transport system for transporting the emitted beam, the entrance of the deflector for output within the output beam pulse. The phase of betatron oscillation is advanced by nπ (n is an integer) from the entrance of the deflector for emission through one or more orbit correction deflectors that change the magnetic field or electric field strength in accordance with the temporal change of the emission angle at A charged particle beam device characterized by being installed at a position.