JP3331982B2 - High-frequency accelerator and annular accelerator using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to the structure of a high-frequency accelerator for accelerating a charged particle beam, and more particularly to the structure of a high-frequency accelerator for a synchrotron for accelerating an ion beam.

[0002]

2. Description of the Related Art In order to accelerate a charged particle beam with high efficiency, impedance matching between a high-frequency accelerator and a power source is essential. Also, for stable acceleration of the charged particle beam, constant monitoring of the acceleration gap voltage is indispensable. In a conventional high-frequency accelerator, as shown in FIG. 8, a circuit element for impedance adjustment and a circuit element for measuring acceleration gap voltage were directly connected to the acceleration gap. FIG. 8A shows an example of a tuned high-frequency accelerator.
A capacitor is connected to the acceleration gap, and the resonance frequency variable range is set in the operation frequency range. FIG. 8B shows an example of a non-tuning type high-frequency accelerator, in which a resistor is connected to the acceleration gap to extend the operable range to the entire operating frequency range. FIG.
(C) shows an example in which a capacitive voltage divider is connected to the acceleration gap to measure the acceleration gap voltage.

The above prior art is described in "OHO'89 High Energy Accelerator Seminar", Chapter 5, High Frequency Accelerator for Proton Synchrotron (pp. 19-32, published by High Energy Accelerator Science Research Encouragement Society) and "Conceptual Design". of a
Proton Therapy SynchrotronFor Loma Linda Universit
y Medical Center ”(p.25-p.27, Fermi NationalAccel
erator Laboratory, 1986).

[0004]

In a conventional high-frequency accelerator, a circuit element for impedance adjustment and a circuit element for measuring an acceleration gap voltage are directly connected to the acceleration gap. Since the voltage of the acceleration gap is high, these circuit elements are required to have a high withstand voltage. In particular, a large vacuum capacitor with high withstand voltage is required for the capacitor. For this reason,
The structure around the acceleration gap is complicated, large, and difficult to assemble and disassemble. Further, since it is difficult to manufacture a high-frequency resistor having high withstand voltage and high power consumption, it has been difficult to obtain a high accelerating gap voltage in a non-tuned high-frequency accelerator.

An object of the present invention is to provide a high-frequency accelerator which can be downsized even when the acceleration gap voltage is high , and an apparatus using the same.
To provide an annular accelerator.

[0006]

A feature of the present invention to achieve the above object is that a plurality of loop antennas penetrating the magnetic core are provided for each of the magnetic cores divided into a plurality of groups, and a high frequency It is to connect the multi-channel high circumferential <br/> wave power to output power, and a circuit element for impedance adjustment or accelerating gap voltage measurement to the loop antenna.

According to the above feature of the present invention, the impedance
Applied to the circuit element for adjusting the acceleration or measuring the acceleration gap voltage.
Use circuit elements with low withstand voltage and low withstand voltage
Therefore, the high-frequency accelerator can be downsized. Also,
By using such a high-frequency accelerator, the annular
Speed reducer can be downsized.

[0008]

[0009]

[0010]

[0011]

[0012]

[0013]

[0014]

[0015]

(Embodiment 1) FIG. 1 shows a first embodiment of the present invention.
FIG. 4 is an explanatory diagram of a high-frequency accelerator according to the embodiment. The high-frequency accelerator 1 includes an acceleration gap 2 for inducing an acceleration electric field of a charged particle beam, a center conductor 3 forming a passage for the charged particle beam and having an acceleration gap, and an annular magnetic body intersecting the center conductor in a chain shape. And a core 4. The magnetic core 4 is divided into a plurality of groups, each of which has a loop antenna 5.
And cross in a chain. Each loop antenna is connected to impedance adjusting means 6 or accelerating gap voltage measuring means 7. Two loop antennas may be provided for each group of magnetic cores, and impedance adjustment and acceleration gap voltage measurement may be connected to each.

The impedance adjusting means 6 is composed of a capacitor, a resistor, an inductance, or a network thereof. For example, a capacitor or an inductance is used to adjust the resonance frequency, and a resistor is used to adjust the sharpness Q value of the resonance.

On the other hand, the accelerating gap voltage measuring means 7 comprises a capacitive voltage divider, a resistive voltage divider, or a combination thereof. The voltage applied to the impedance adjusting means 6 or the accelerating gap voltage measuring means 7 is a value obtained by dividing the voltage of the accelerating gap 2 by the number of divided groups of the magnetic core. In this embodiment, the voltage is 1/6 of the accelerating gap voltage. Becomes

The effect of reducing the applied voltage increases as the number of divided groups increases. When the magnetic core is ultimately divided into individual magnetic cores, the applied voltage is up to a value obtained by dividing the acceleration gap voltage by the number of magnetic cores. It is reduced.

Since the voltage applied to the impedance adjusting means 6 or the accelerating gap voltage measuring means 7 becomes low,
The impedance adjusting means 6 or the accelerating gap voltage measuring means 7 may have a low withstand voltage and can be miniaturized.

In this embodiment, a loop antenna is provided for each divided group of the magnetic material and the impedance adjusting means 6 or the accelerating gap voltage measuring means 7 is connected, but this is not always necessary. For example, when the influence on the high-frequency characteristics due to the individual difference between the magnetic cores and the difference in the installation position can be neglected, a single set of loop antenna and measuring means is sufficient for measuring the acceleration gap voltage. If the number of the impedance adjusting means 6 or the accelerating gap voltage measuring means 7 is reduced, the high-frequency accelerator becomes more compact.

When the number of the impedance adjusting means 6 is increased, the impedance can be adjusted more accurately over the entire length of the high-frequency accelerator.

According to this embodiment, even when the acceleration gap voltage of the high-frequency accelerator is as high as several tens of kV, impedance adjustment and voltage measurement of the acceleration gap can be achieved with a commercially available small high-frequency circuit element having a withstand voltage of 1 kV or less. As a result, a high-frequency accelerator that is small and easy to assemble and disassemble can be realized.

(Embodiment 2) FIG. 2 is an explanatory view of a high-frequency accelerator according to a second embodiment of the present invention. In this embodiment, the loop antenna 5 is provided by grouping a plurality of groups of the divided magnetic cores, and the impedance adjusting unit 6 or the accelerating gap voltage measuring unit 7 is connected thereto. In the present embodiment, the voltage applied to them is の of the voltage of the acceleration gap 2 and the effect of reducing the applied voltage is smaller than in the first embodiment. 7 may have low withstand voltage and can be miniaturized. Also. Since the number of loop antennas, impedance adjusting means, and accelerating gap voltage measuring means can be reduced, the high-frequency accelerator can be downsized.

(Embodiment 3) FIG. 3 is an explanatory view of a high-frequency accelerator according to a third embodiment of the present invention. In the present embodiment, the loop antenna 5 is provided by integrating all the magnetic material cores, and the impedance adjusting means 6 or the measuring means 7 of the acceleration gap voltage is connected. A power feeding loop antenna 9 is used to feed power from the high frequency power supply 8 to the high frequency accelerator 1. In this case, the voltage applied to the impedance adjusting means 6 or the acceleration gap voltage measuring means 7 is the same as the voltage of the acceleration gap 2, and there is no effect of reducing the applied voltage.
However, since the feed line, the vacuum capacitor, or the resistor connected to the acceleration gap in the conventional high-frequency accelerator (FIG. 8) is not provided, the space in the acceleration gap can be effectively used for loading the magnetic material. As a result, the overall length of the device can be reduced.
Furthermore, since the center conductor 3 has no object to be connected, it can be completely structurally free from the main body of the high-frequency accelerator. As a result, assembly and disassembly of the device are facilitated. The effect of the present embodiment can be similarly achieved by using a loop antenna for power supply from the high-frequency power supply 8 in the first and second embodiments.

(Embodiment 4) FIG. 4 is an explanatory view of a high-frequency accelerator according to a fourth embodiment of the present invention. In this embodiment, the magnetic core 4 is divided into a plurality of groups, each of which intersects the feeding loop antenna 9 in a chain shape. Electric power from the multi-channel high-frequency power supply 8 is supplied to the high-frequency accelerator 1 through the feeding loop antenna 9. The impedance adjusting means 6 or the accelerating gap voltage measuring means 7
It is connected to the feeding loop antenna 9. The induced voltage in the acceleration gap 2 is the sum of the voltages applied to the respective feeding loop antennas 9, and the voltage applied to the impedance adjusting means 6 or the acceleration gap voltage measuring means 7 is obtained by dividing the acceleration gap voltage into the divided groups of the magnetic cores. It is a value divided by a number. As in the first embodiment, since the voltage applied to the impedance adjusting means 6 or the acceleration gap voltage measuring means 7 is reduced, the impedance adjusting means 6 or the accelerating gap voltage measuring means 7 is reduced.
Can have a low withstand voltage and can be miniaturized.

In this embodiment, there is no need to separately provide a loop antenna for impedance adjustment or acceleration gap voltage measurement, so that the configuration of the high-frequency accelerator can be simplified.

(Embodiment 5) FIG. 5 is an explanatory view of a high-frequency accelerator according to a fifth embodiment of the present invention. Magnetic core 4
Are divided into a plurality of groups, each of which crosses a plurality of loop antennas 5 and 9 in a chain shape. The impedance adjusting means 6a and 6c connected to each loop antenna are connected to the other impedance adjusting means 6b and the magnetic core 4 (L
(C parallel circuit) to form a network. In this embodiment, a bridge T-type network is formed, and the frequency characteristics of the voltage induced in the acceleration gap 2 can be adjusted.

The voltage applied to each loop antenna is a value obtained by dividing the accelerating gap voltage by the number of divided groups of the magnetic core, and the voltage applied to the impedance adjusting means 6 becomes lower as in the first embodiment. Therefore, the impedance adjusting means 6 may have low withstand voltage and can be downsized.

As in the first embodiment, if the number of the impedance adjusting means 6 is reduced, the high-frequency accelerator becomes smaller, and if the number is increased, the impedance is more accurately adjusted over the entire length of the high-frequency accelerator. can do.

The above-described impedance adjustment circuit network can be integrated into the impedance adjustment means 6c, so that the high-frequency accelerator becomes more compact. (Embodiment 6) FIG. 6 is an explanatory view of a high-frequency accelerator according to a sixth embodiment of the present invention. The magnetic core 4 is divided into a plurality of groups, each of which intersects the loop antenna 5 in a chain shape. Each loop antenna is connected to an acceleration gap voltage measuring means 7.

The acceleration gap voltage measuring means 7 is a capacitive voltage divider. In the present embodiment, the capacitive voltage dividers located on the left and right sides of the acceleration gap are connected in series, and these two signals are combined by the differential amplifier 14 and at the same time a long transmission line to the control room is driven. The capacitor 15 is connected to adjust the voltage division ratio. The provision of the differential amplifier 14 and the capacitor 15 simplifies the subsequent signal processing system. Increasing the number of capacitive voltage dividers connected in series,
If the voltage in the acceleration gap can be accurately measured and reduced, the RF accelerator becomes more compact.

As in the first embodiment, the voltage applied to each loop antenna is a value obtained by dividing the acceleration gap voltage by the number of divided groups of the magnetic core. The acceleration gap voltage measuring means 7
Can have a low withstand voltage and can be miniaturized.

In this embodiment, a capacitive voltage divider is used, but a resistive voltage divider may be used.

(Embodiment 7) FIG. 7 is an explanatory view of a ring accelerator according to a seventh embodiment of the present invention. The annular accelerator shown in the present embodiment includes an injector 10 for injecting a charged particle beam transported from a pre-stage accelerator into a ring, a deflection electromagnet 1 for deflecting the trajectory of the charged particle beam and orbiting along the ring.
1, a focusing electromagnet 12 for giving a focusing force so that a charged particle beam does not spread, a high-frequency accelerator for accelerating an incident beam to a required energy, and an emitter 13 for taking out a charged particle beam having reached a predetermined energy out of a ring. Be composed.

In order to stably accelerate the charged particle beam by the high-frequency accelerator, it is necessary to increase the exciting current of the bending electromagnet and the focusing electromagnet in synchronization with the acceleration. In addition, since the ring circulation cycle of the charged particle beam is shortened with acceleration, the frequency of the acceleration gap voltage of the high-frequency accelerator, that is, the output frequency of the high-frequency power supply needs to be correspondingly increased. Therefore, constant monitoring of the acceleration gap voltage is indispensable for stable acceleration of the charged particle beam. Further, in order to accelerate a charged particle beam with high efficiency, impedance matching between a high-frequency accelerator and a power supply over a wide frequency band is essential.
The above object can be easily achieved by providing the annular accelerator with the high-frequency accelerator described in the first to sixth embodiments. In particular, the acceleration gap voltage of the high-frequency accelerator is several tens kV.
Even if it is high, since a resistor with a realistic size (500 V-1 kW) with a withstand voltage and power consumption can be used, a non-tuned high-frequency accelerator can be adopted, and the charged particle beam is adjusted to the ring orbital cycle. That is, it is not necessary to control the resonance frequency of the high-frequency accelerator according to the output frequency of the high-frequency power supply, and the operation control of the annular accelerator becomes easy.

[0036]

As described above, according to the present invention,
Since circuit elements with low withstand voltage can be used,
The wave accelerator can be downsized. In addition, such high-frequency
By using a speed device, the annular accelerator can be miniaturized.
You.

[0037]

[0038]

[0039]

[0040]

[0041]

[Brief description of the drawings]

FIG. 1 is a diagram showing a high-frequency accelerator 1 according to a first embodiment.

FIG. 2 is a diagram showing a high-frequency accelerator 1 according to a second embodiment.

FIG. 3 is a view showing a high-frequency accelerator 1 according to a third embodiment.

FIG. 4 is a diagram showing a high-frequency accelerator 1 according to a fourth embodiment.

FIG. 5 is a diagram showing a high-frequency accelerator 1 according to a fifth embodiment.

FIG. 6 is a diagram showing a high-frequency accelerator 1 according to a sixth embodiment.

FIG. 7 is a view showing a ring accelerator according to a seventh embodiment.

FIG. 8 is a view showing a conventional high-frequency accelerator.

[Description of Signs] 1 ... High-frequency accelerator, 2 ... Acceleration gap, 3 ... Center conductor, 4
... magnetic core, 5 ... loop antenna, 6 ... impedance adjusting means, 7 ... accelerating gap voltage measuring means, 8 ... high frequency power supply, 9 ... feeding loop antenna, 10 ... injector, 11
... deflecting electromagnet, 12 ... focusing electromagnet, 13 ... exiter, 14
... Differential amplifier, 15 ... Capacitor.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-9-161997 (JP, A) JP-A-11-1444898 (JP, A) JP-A-8-213198 (JP, A) JP-A-7- 6900 (JP, A) JP 2000-77200 (JP, A) JP 11-307300 (JP, A) JP 11-204300 (JP, A) JP 9-219300 (JP, A) JP-A-9-167699 (JP, A) JP-A-3-74097 (JP, A) JP-B-4-4393 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) H05H7 / 18 H05H 9/00 H05H 13/04

Claims (4)

(57) [Claims] An annular magnetic core comprising: a central conductor having a path for a charged particle beam formed therein and having an acceleration gap for inducing an accelerated electric field of the charged particle beam; and a plurality of annular magnetic cores. in the high frequency accelerator in which the center conductor is through the, the magnetism of the plurality of magnetic cores are divided into a plurality of groups, provided for each of the plurality of groups of said magnetic core, and in the group A plurality of loop antennas penetrating the body core, a multi-channel high-frequency power supply connected to the loop antenna and outputting high-frequency power, and a circuit element for impedance adjustment or acceleration gap voltage measurement connected to the loop antenna A high-frequency accelerator, comprising: 2. An annular magnetic core comprising: a central conductor having a path for a charged particle beam formed therein and having an acceleration gap for inducing an accelerated electric field of the charged particle beam; and a plurality of annular magnetic cores. in the high frequency accelerator in which the center conductor is through the, the magnetism of the plurality of magnetic cores are divided into a plurality of groups, provided for each of the plurality of groups of said magnetic core, and in the group A plurality of first loop antennas penetrating the body core, a multi-channel high-frequency power supply connected to the first loop antenna and outputting high-frequency power, and a second impedance adjustment power supply connected to the first loop antenna. One circuit element and a plurality of second loop antennas provided for each of the plurality of groups separately from the first loop antenna and penetrating the magnetic core. A second circuit element for impedance adjustment connected to the second loop antenna; and a third circuit element connected to form a circuit network with the first circuit element and the second circuit element. And a high-frequency accelerator. 3. An injector for injecting a charged particle beam, a bending electromagnet for orbiting the incident charged particle beam along a circular orbit, a high-frequency accelerator for accelerating the orbiting charged particle beam, and an accelerated charged particle An annular accelerator including an emitter that emits a beam, wherein the high-frequency accelerator includes a plurality of annular magnetic cores divided into a plurality of groups, and a passage for a charged particle beam formed therein, and the annular accelerator. of the arranged center conductor to penetrate the magnetic core, is provided for each of the plurality of groups of said magnetic core, and a plurality of loop antennas penetrating the magnetic core in the group, the said loop antenna are connected, and a multi-channel high circumferential <br/> wave power for outputting high-frequency power, impedance adjustment is connected to the loop antenna, or for accelerating gap voltage measurement Cyclic accelerators and having a circuit element. 4. An injector for injecting a charged particle beam, a bending electromagnet for orbiting the incident charged particle beam along a circular orbit, a high-frequency accelerator for accelerating the orbiting charged particle beam, and an accelerated charged particle An annular accelerator including an emitter that emits a beam, wherein the high-frequency accelerator includes a plurality of annular magnetic cores, a passage for a charged particle beam formed therein, and the annular magnetic core penetrates the annular magnetic core. a center conductor disposed, the magnetic
Provided for each of the plurality of groups of body cores, and
A first loop antenna penetrating the magnetic core in the loop, and a multi-channel connected to the first loop antenna
A high-frequency power supply that outputs a high-frequency power to the channel , a second loop antenna that is provided separately from the first loop antenna, and penetrates the magnetic core, and an impedance adjustment or that is connected to the second loop antenna. A ring accelerator having a circuit element for measuring an acceleration gap voltage.