Amplifiers, accelerators, and therapeutic devices

Abstract

The present invention provides a widening device, an accelerator, and a treatment device that can suppress the increase in power supply size. [Solution] The amplifier 1 is equipped with multiple semiconductor elements 10. By using semiconductor elements 10, the amplifier 1 does not have a filament like a vacuum tube, thus eliminating the need for DC power supply. Here, one power supply 11 is provided for the multiple semiconductor elements 10. That is, the number of power supplies 11 in the amplifier 1 can be reduced compared to the case where one power supply 11 is provided for one semiconductor element 10 (comparative example shown in Figure 6). Therefore, the size of the power supply 11 can be suppressed.

Description

Technical Field

[0001] The present invention relates to an amplifier, an accelerator, and a treatment device.

Background Art

[0002] Conventionally, as a technology in this field, an amplifier described in Patent Document 1 below is known. The amplifier amplifies high-frequency power for an accelerator using a vacuum tube.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, in the amplifier using a vacuum tube as described above, since it has a filament electrode for generating thermoelectrons, it is necessary to supply DC (or AC) power to the filament regardless of the specifications of the amplifier (continuous operation specifications or pulse specifications). Therefore, there was a problem that the power supply became large-sized.

[0005] An object of the present invention is to provide an amplifier, an accelerator, and a treatment device that can suppress the enlargement of the power supply.

Means for Solving the Problems

[0006] The amplifier according to the present invention is an amplifier that amplifies high-frequency power for an accelerator, and includes a plurality of semiconductor elements and a power supply that supplies DC power to the plurality of semiconductor elements, and one power supply is provided for the plurality of semiconductor elements.

[0007] The amplifier according to the present invention comprises multiple semiconductor elements. A single power supply is provided for these multiple semiconductor elements. That is, the number of power supplies in the amplifier can be reduced compared to the case where one power supply is provided for each semiconductor element. Therefore, an increase in the size of the power supply can be suppressed.

[0008] The amplifier may further include a capacitor that supplies power to multiple semiconductor elements. In this case, the power supply can store energy in the capacitor when the multiple semiconductor elements are not performing amplification operations. Then, the capacitor can supply the stored power when the multiple semiconductor elements are performing amplification operations. This allows sufficient power to be supplied to multiple semiconductor elements without increasing the size of the power supply.

[0009] High-frequency power can be in the form of pulsed output. In this case, power only needs to be supplied to multiple semiconductor elements at the timing when amplification is performed. Therefore, sufficient power can be supplied to multiple semiconductor elements without increasing the size of the power supply.

[0010] The accelerator according to the present invention accelerates particles using high-frequency power amplified by the amplifier described above. In this case, the accelerator can accelerate particles using an amplifier that suppresses the increase in power supply size.

[0011] The accelerator can be a linear accelerator that accelerates particles in a straight line. In the case of a linear accelerator, pulsed amplifiers are often used, and in that case, power only needs to be supplied at the timing when the amplification operation is performed.

[0012] The therapeutic device according to the present invention performs treatment using a particle beam accelerated by the aforementioned accelerator. In this case, the therapeutic device can perform treatment using an amplifier that suppresses the increase in power supply size. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a widening device, an accelerator, and a treatment device that can suppress the increase in power supply size. [Brief explanation of the drawing]

[0014] [Figure 1] This is a schematic diagram of a therapeutic device comprising an amplifier and an accelerator according to this embodiment. [Figure 2] This is a schematic diagram of the accelerator and RF system configuration. [Figure 3] This is a block diagram of the amplifier. [Figure 4] This is a circuit diagram of an amplifier. [Figure 5] This is a block diagram showing an RF system equipped with an amplifier according to a comparative example. [Figure 6] This is a block diagram of the amplifier related to the comparative example. [Modes for carrying out the invention]

[0015] The embodiments of the amplifier, accelerator, and treatment device according to the present invention will be described in detail below with reference to the drawings. Note that in some cases, features may be exaggerated in the drawings, and the dimensional ratios and shapes of the parts of the treatment device shown in the drawings do not necessarily match the actual device, nor do they necessarily match between drawings. Furthermore, the treatment device is not limited to the one shown in Figure 1, and the amplifier according to this embodiment may be broadly applied to any device that performs treatment using particle beams. Figure 1 is a schematic diagram of a treatment device equipped with the amplifier and accelerator according to this embodiment. As shown in Figure 1, the treatment device 100 of this embodiment is a device that performs treatment by irradiating a lesion (e.g., a tumor, etc.) inside a patient P (the irradiated body) with a particle beam. Here, the particle beam is, for example, a proton beam or a heavy ion beam. In this embodiment, a heavy ion beam is used.

[0016] The treatment device 100 includes accelerators 105 and 106 that accelerate particles and emit a particle beam, an irradiation unit 103 that irradiates the patient P with the particle beam, a rotating gantry 13 that rotates the irradiation unit 103 around a horizontal axis of rotation A around the treatment table 7 on which the patient P lies, and a transport line 107 that connects the downstream accelerator 106 and the irradiation unit 103 and transports the charged particle beam from the accelerator 106 to the irradiation unit 103. The transport line 107 has a plurality of quadrupole electromagnets 113 for focusing the charged particle beam and a plurality of bending magnets 115 for bending the charged particle beam.

[0017] The treatment device 100 includes an RF system 50 that supplies high-frequency power to the upstream accelerator 105. Figure 2 is a schematic diagram of the accelerator 105 and the RF system 50. The RF system 50 is a system equipped with an amplifier 1 according to this embodiment. The amplifier 1 is a device that amplifies the high-frequency power supplied to the accelerator 105. As shown in Figure 2, the accelerator 105 accelerates particles with the high-frequency power amplified by the amplifier 1 and emits a particle beam B. In this embodiment, a linear accelerator that linearly accelerates particles (heavy particles) is used as the upstream accelerator 105. A linac or the like may be used as the linear accelerator. The accelerator 105, which is a linear accelerator, has a plurality of cylindrical electrodes 105a arranged in a straight line. High-frequency power is supplied to each cylindrical electrode 105a. Particles are accelerated by passing through the gaps between the cylindrical electrodes 105a and are emitted as a particle beam B. A synchrotron may be used as the downstream accelerator 106 (see Figure 1).

[0018] The RF system 50 includes a control unit 2, an amplifier 1, a coupler 3, and a tuner 5. The control unit 2 controls the supply of high-frequency power to the accelerator 105. The control unit 2 outputs high-frequency power to the accelerator 105 via the output line L1. In this embodiment, the high-frequency power output by the control unit 2 is pulse output. The frequency of the high-frequency power is not particularly limited. The accelerator 105 transmits a resonating signal to the control unit 2 via the line L2 in the accelerator 105. The amplifier 1 is provided on the output line L1. The coupler 3 is connected to the accelerator 105 and also connected to the output line L1. The coupler 3 is a device for efficiently injecting the high-frequency power from the output line L1 into the accelerator 105. A detector 6 is provided between the amplifier 1 and the coupler 3 on the output line L1. The detector 6 detects the amplified high-frequency power and transmits the detection result to the control unit 2 via the line L3. The tuner 4 is a device for correcting the thermal deformation of the resonator in the accelerator 105. The control unit 2, for example, compares the phase of the signal from the accelerator 105 with the reference signal in the control unit 2. Also, the control unit 2 performs a process of controlling the accelerating voltage. Also, the control unit 2 detects a deviation in the resonance frequency based on the result of the detector 6. The control unit 2 transmits a command signal for correction to the tuner 5 via the line L4.

[0019] Next, referring to FIGS. 3 and 4, the configuration of the amplifier 1 will be described in detail. FIG. 3 is a block diagram of the amplifier 1. FIG. 4 is a circuit diagram of the amplifier 1. As shown in FIG. 3, the amplifier 1 includes a plurality of semiconductor elements 10, a power supply 11 that supplies DC power to the plurality of semiconductor elements 10, and a capacitor 12 that supplies power to the plurality of semiconductor elements 10. In the amplifier 1, one power supply 11 is provided for the plurality of semiconductor elements 10.

[0020] In this embodiment, the amplifier 1 has four semiconductor elements 10A, 10B, 10C, and 10D. However, the number of semiconductor elements 10 is not particularly limited. The semiconductor elements 10A, 10B, 10C, and 10D are high-frequency amplification elements having a function of high-frequency amplification by applying a DC bias voltage. A current flows through the semiconductor elements 10A, 10B, 10C, and 10D during amplification. The semiconductor elements 10A, 10B, 10C, and 10D are provided between the input-side line L1a and the output-side line L1b of the output line L1. The semiconductor elements 10A, 10B, 10C, and 10D are connected in parallel between the line L1a and the line L1b. Note that the input-side line L10 and the output-side line L11 are respectively connected to the semiconductor elements 10A, 10B, 10C, and 10D.

[0021] The power supply 11 supplies DC power to each of the plurality of semiconductor elements 10A, 10B, 10C, and 10D. The power supply 11 is connected to each semiconductor element 10A, 10B, 10C, and 10D via the line L5 and the branch lines L6A, L6B, L6C, and L6D branched from the line L5. A resistor 15 is disposed on the line L5 before branching. A capacitor 12 is connected to the line L5 downstream of the resistor 15. The capacitor 12 can store electric charges with the current from the power supply 11 when the amplifier 1 is not performing an amplification operation. Also, the capacitor 12 supplies the stored current to the semiconductor elements 10A, 10B, 10C, and 10D when the amplifier 1 is performing an amplification operation.

[0022] Referring to FIG. 4, the circuit diagram of the amplifier 1 will be described. As shown in FIG. 4, the lines L5a and L5b constituting the line L5 are connected to the power supply 11. A capacitor 12 is provided on the line L7 connecting the line L5a and the line L5b. A resistor 15 is provided between the connection portion of the line L7 and the power supply 11 in the line L5a.

[0023] The semiconductor element 10A comprises a transistor section 20 and a coupling section 21. The transistor section 20 is connected to the input line L10, line L6a branched from line L5a, and line L6b branched from line L5b. The transistor section 20 is supplied with power from the capacitor 12 via lines L6a and L6b, thereby amplifying the high-frequency power from line L10. The coupling section 21 is provided on the branched line L6a and supplies power to the output line L11 by coupling coils. The semiconductor elements 10B, 10C, and 10D in Figure 4 have the same configuration as semiconductor element 10A. The output line L11 of semiconductor element 10B is connected to "B" in the output line L1b. The output line L11 of semiconductor element 10C is connected to "C" in the output line L1b. The output line L11 of semiconductor element 10D is connected to "D" in the output line L1b.

[0024] Next, the operation and effects of the amplifier 1, accelerator 105, and treatment device 100 according to this embodiment will be described.

[0025] First, let's describe the comparative example. Figure 5 is a block diagram showing an RF system 250 equipped with an amplifier 200 related to the comparative example. The amplifier 200 shown in Figure 5 is a vacuum tube amplifier. This amplifier 200 comprises a low-power amplifier 201, an intermediate-power amplifier 202, and a high-power amplifier 203. Power supplies 204 and 205 are connected to the intermediate-power amplifier 202 and the high-power amplifier 203. In the vacuum tube amplifier 200, since it has a filament electrode that generates thermionic electrons, it was necessary to apply DC (or AC) current to the filament regardless of the specifications of the amplifier 200 (whether it is a continuous operation specification or a pulse specification). Therefore, there was a problem in that the power supply had to be large.

[0026] Figure 6 is a block diagram of amplifier 200 according to the comparative example. In amplifier 200, one power supply 11 is provided for each semiconductor element 10A. Therefore, four power supplies 11 are provided for the four semiconductor elements 10A, 10B, 10C, and 10D. In amplifier 200 according to the comparative example, four power supplies 11 are provided to install DC power supplies corresponding to the amplification operation current. Thus, providing four power supplies 11 presents the problem of increasing the size of the power supply.

[0027] In contrast, the amplifier 1 according to this embodiment includes a plurality of semiconductor elements 10. By using semiconductor elements 10, the amplifier 1 does not have a filament like a vacuum tube, thus eliminating the need for DC power supply. Here, one power supply 11 is provided for the plurality of semiconductor elements 10. That is, the number of power supplies 11 in the amplifier 1 can be reduced compared to the case where one power supply 11 is provided for one semiconductor element 10 (comparative example shown in Figure 6). Therefore, the size of the power supply 11 can be suppressed.

[0028] Amplifier 1 may further include a capacitor 12 that supplies power to multiple semiconductor elements 10. In this case, the power supply 11 can store energy in the capacitor 12 when the multiple semiconductor elements 10 are not performing amplification operations. Then, the capacitor 12 can supply the stored power when the multiple semiconductor elements 10 are performing amplification operations. This makes it possible to supply sufficient power to multiple semiconductor elements without increasing the size of the power supply 11.

[0029] The high-frequency power may be a pulse output. In this case, power only needs to be supplied to the multiple semiconductor elements 10 at the timing when amplification is performed. Therefore, sufficient power can be supplied to the multiple semiconductor elements 10 without increasing the size of the power supply 11.

[0030] In this embodiment, the accelerator 105 accelerates particles using high-frequency power amplified by the amplifier 1 described above. In this case, the accelerator 105 can accelerate particles using an amplifier 1 that suppresses the increase in size of the power supply 11.

[0031] Accelerator 105 may be a linear accelerator that accelerates particles in a straight line. In the case of a linear accelerator, a pulsed amplifier 1 is often used, in which case power only needs to be supplied at the timing when amplification is performed. Note that even if it is a linear accelerator, it may not be a pulsed type.

[0032] The treatment device 100 according to this embodiment performs treatment using a particle beam accelerated by the accelerator 105 described above. In this case, the treatment device 100 can perform treatment using an amplifier 1 that suppresses the increase in size of the power supply 11.

[0033] Specifically, in the comparative example amplifier 200 shown in Figure 6, the amplification voltage for each semiconductor element 10 is 50V and 45Ap, and there are four such semiconductor elements 10. Amplifier 200 uses a power supply 11 corresponding to the amplification current. If each power supply 11 is 2500W, then using four power supplies 11 results in a 10kW DC power supply specification. In contrast, amplifier 1 according to this embodiment limits the power supply 11 to 100W. Furthermore, since amplifier 1 has only one power supply 11, the DC power supply specification of amplifier 1 is 0.1kW. Thus, in amplifier 1 according to this embodiment, the DC power supply specification can be reduced from 10kW to 0.1kW compared to the comparative example. Also, in the comparative example shown in Figure 6, the semiconductor elements 10 and power supply 11 are connected with a wire of approximately 0.1Ω. In this case, the required power supply current is about 23A. In amplifier 1, by setting the resistor 15 to 1Ω, the required power supply current can be reduced to 1.4A. In this case, it would take about three times 70ms for the voltage to recover. However, in the case of a synchrotron injector, the high-frequency operating period is 1 to 3 seconds, so if the voltage recovers in about 200ms, there will be no problem.

[0034] The present invention is not limited to the embodiments described above.

[0035] For example, the circuit configuration shown in Figure 4 is merely an example and can be modified as appropriate. For instance, although amplifier 1 has only one capacitor 12, capacitors may be provided within each semiconductor element 10. [Explanation of Symbols]

[0036] 1... Amplifier, 10... Semiconductor element, 11... Power supply, 12... Capacitor, 100... Treatment device, 105... Accelerator.

Claims

1. An amplifier for amplifying high-frequency power to an accelerator, Multiple semiconductor elements, The system comprises a power supply that supplies DC power to a plurality of semiconductor elements, An amplifier in which one power supply is provided for multiple semiconductor elements.

2. The amplifier according to claim 1, further comprising a capacitor that supplies power to a plurality of semiconductor elements.

3. The amplifier according to claim 1, wherein the high-frequency power is a pulse output.

4. An accelerator that accelerates particles using high-frequency power amplified by an amplifier according to any one of claims 1 to 3.

5. The accelerator according to claim 4, which is a linear accelerator that accelerates particles in a straight line.

6. A treatment device that performs treatment using a particle beam accelerated by the accelerator described in claim 4.

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