Programmable radio frequency waveform generator for a synchrocyclotron
First Claim
1. A synchrocyclotron comprising:
- a magnetic field generator to produce a magnetic field;
a resonant circuit, comprising;
electrodes, disposed within a cavity between magnetic poles, having a gap therebetween across a the magnetic field; and
a variable reactive element in circuit with the electrodes to vary a resonant frequency of the resonant circuit;
andan extraction channel to receive charged particles from the cavity and to output a particle beam from the synchrocyclotron;
a sensor to measure a voltage in the resonant circuit; and
a voltage input generator to provide adjust a frequency of a voltage input to the resonant circuit based on an intensity of the particle beam output by the synchrocyclotron and a frequency of the voltage measured in the resonant circuit, the voltage input being an oscillating voltage that varies in frequency over a time of acceleration of the charged particles.
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Accused Products
Abstract
A synchrocyclotron comprises includes a resonant circuit that includes electrodes having a gap therebetween across the magnetic field. An oscillating voltage input, having a variable amplitude and frequency determined by a programmable digital waveform generator generates an oscillating electric field across the gap. The synchrocyclotron can include a variable capacitor in circuit with the electrodes to vary the resonant frequency. The synchrocyclotron can further include an injection electrode and an extraction electrode having voltages controlled by the programmable digital waveform generator. The synchrocyclotron can further include a beam monitor. The synchrocyclotron can detect resonant conditions in the resonant circuit by measuring the voltage and or and/or current in the resonant circuit, driven by the input voltage, and adjust the capacitance of the variable capacitor or the frequency of the input voltage to maintain the resonant conditions. The programmable waveform generator can adjust at least one of the oscillating voltage input, the voltage on the injection electrode and the voltage on the extraction electrode according to beam intensity and in response to changes in resonant conditions.
665 Citations
109 Claims
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1. A synchrocyclotron comprising:
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a magnetic field generator to produce a magnetic field; a resonant circuit, comprising; electrodes, disposed within a cavity between magnetic poles, having a gap therebetween across a the magnetic field; and a variable reactive element in circuit with the electrodes to vary a resonant frequency of the resonant circuit;
andan extraction channel to receive charged particles from the cavity and to output a particle beam from the synchrocyclotron; a sensor to measure a voltage in the resonant circuit; and
a voltage input generator to provide adjust a frequency of a voltage input to the resonant circuit based on an intensity of the particle beam output by the synchrocyclotron and a frequency of the voltage measured in the resonant circuit, the voltage input being an oscillating voltage that varies in frequency over a time of acceleration of the charged particles. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of accelerating particles in a synchrocyclotron, comprising:
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providing particles in a cavity of the synchrocyclotron; providing a resonant circuit in the cavity, the resonant circuit comprising accelerating electrodes having a gap therebetween across a magnetic field;
andusing a sensor to measure a voltage in the resonant circuit;
withusing a voltage input generator, applying an oscillatingadjusting, based on an intensity of a particle beam output by the synchrocyclotron and a frequency of a voltage measured in the resonant circuit, a frequency of a voltage input that varies in frequency during acceleration of the particles to the resonant circuit, the oscillating voltage input creating an oscillating electric field across the gap that accelerates the particles in the synchrocyclotron cavity; and receiving the particles from the cavity in an extraction channel and outputting a particle beam from the extraction channel. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A particle accelerator configured to generate a particle beam, the particle accelerator comprising:
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an ion source to provide pulses of charged particles that are accelerated in a cavity to form the particle beam; a beam monitor to obtain information about the particle beam, the information comprising information about an intensity of the particle beam; and a waveform generator comprising a controller to receive the information about the intensity and to write data to memory, the waveform generator comprising a driver to provide voltage to the cavity to accelerate the charged particles; and circuitry to control operation of the ion source based on the information about the intensity so that the pulses are provided at timed instances in synchronism with a sweep of a frequency of the voltage that accelerates the charged particles. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28)
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29. A particle accelerator configured to generate a particle beam, the particle accelerator comprising:
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an ion source to inject charged particles into a resonant cavity; magnetic pole pieces that border the resonant cavity, the resonant cavity having a radio frequency (RF) voltage to accelerate the charged particles to produce the particle beam; a feedback system to provide at least one property of the particle beam; and circuitry to receive an injection control pulse that extends over multiple cycles of the RF voltage and to control, based on the at least one property, the injection control pulse based on cycles of the RF voltage so that charged particles are injected continuously over at least some of the multiple cycles. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36, 37)
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38. A synchrocyclotron comprising:
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magnetic pole pieces that border a cavity; an ion source to provide, to the cavity, ions that are accelerated to form a particle beam; a voltage generator to provide voltage to the cavity, the voltage comprising an oscillating voltage having a frequency that varies over a time of acceleration of the ions; a sensor to measure the oscillating voltage in the cavity; and a control circuit to control, based on the oscillating voltage measured by the sensor, a timing at which ions are provided by the ion source, the timing being controlled so that ions are provided into the cavity for a limited time and at a same point in each of multiple frequency sweeps of the oscillating voltage, at least part of the control circuit comprising digital circuitry, the digital circuitry comprising an interface that provides a data link to a computer. - View Dependent Claims (39, 40, 41, 42, 43, 44, 45, 46)
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47. A synchrocyclotron comprising:
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a particle source to provide charged particles into a cavity having a magnetic field; a voltage circuit to cause acceleration of the charged particles in the cavity via an oscillating electric field, the oscillating electric field to vary over a time of acceleration of the charged particles, the voltage circuit comprising a resonant circuit that comprises accelerating electrodes having a gap therebetween across the magnetic field and a driver to drive an oscillating voltage input to produce the oscillating electric field across the gap, the oscillating voltage input to vary over the time of acceleration of the charged particles; and a control circuit to control the particle source to provide the charged particles for a limited time during each of multiple frequency sweeps of the oscillating electric field across the gap, the limited time synchronizing with an acceptance phase angle of the synchrocyclotron, at least part of the control circuit comprising digital circuitry, the digital circuitry comprising an interface that provides a data link to a computer. - View Dependent Claims (48, 49, 50, 51, 52, 53, 54, 55)
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56. A particle accelerator comprising:
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a cavity having a magnetic field; an ion source to provide charged particles to the cavity; a digital waveform generator to apply an oscillating voltage input to a resonant circuit that comprises accelerating electrodes having a gap therebetween across the magnetic field to drive an oscillating electric field across the gap and accelerate the charged particles within the cavity; a beam monitor to measure a property of a particle beam comprised of the charged particles that have been accelerated; wherein the digital waveform generator is configured to control the oscillating voltage input and the ion source to compensate for variations in the property of the particle beam; and a programmable processor to control at least part of the digital waveform generator. - View Dependent Claims (57, 58, 59, 60, 61, 62, 63)
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64. A particle accelerator comprising
magnetic pole pieces that border a cavity; -
a voltage generator to provide voltage to the cavity, the voltage comprising an oscillating voltage having a frequency that varies over a time of acceleration of charged particles; an ion source that is controllable to output, over a period of time, pulses of charged particles that are accelerated in the cavity based on the oscillating voltage to form a particle beam; control circuitry to regulate a current of the particle beam by controlling the ion source so as not to output at least some of the pulses during the period of time; and a beam monitor to obtain at least one property of the particle beam; wherein the control circuitry is configured to control a timing at which some of the pulses are output based on the oscillating voltage and an acceptance phase angle of the synchrocyclotron and to control, based on the at least one property, the ion source so as to change a number of the pulses that are not output during the period of time across different cycles of the voltage. - View Dependent Claims (65, 66, 67, 68, 69, 70)
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71. A particle accelerator configured to generate a particle beam, the particle accelerator comprising:
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an ion source to provide charged particles into a resonant cavity; electrodes in the resonant cavity, the electrodes being separated by a gap; a voltage circuit to output a radio frequency (RF) voltage to at least one of the electrodes to produce an oscillating electric field across the gap, the RF voltage having a frequency that varies to accelerate the charged particles to form the particle beam; and a feedback system to detect information about the frequency of the oscillating electric field, and to adjust a timing of operation of the voltage circuit and the ion source based on the information so that the charged particles are provided to the resonant cavity in synchronism with a variation in the frequency of the RF voltage. - View Dependent Claims (72, 73, 74, 75, 76, 77, 78, 79)
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80. A synchrocyclotron configured to output a particle beam, the synchrocyclotron comprising:
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an ion source to provide charged particles to a resonant cavity for orbital acceleration to form the particle beam, the particle beam comprising multiple pulses; a voltage source to provide a radio frequency (RF) voltage to the resonant cavity, the voltage source comprising an amplifier to change an amplitude of the RF voltage before providing the RF voltage to the resonant cavity; a control system to control operation of the ion source in order to control intensities of individual pulses among the multiple pulses comprising the particle beam, the control system comprising a programmable processor to control the operation of the ion source based on a frequency of the RF voltage in the resonant cavity; and a beam monitor to detect an intensity of the particle beam; wherein the programmable processor is configured to control operation of the ion source based also on information about the detected intensity. - View Dependent Claims (81, 82, 83, 84, 85, 86, 87, 88, 89)
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90. A synchrocyclotron comprising:
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magnetic pole pieces that border a cavity in which charged particles accelerate; a resonant circuit to control a resonant frequency within the cavity; a voltage circuit to provide voltage to the resonant circuit, the voltage comprising an oscillating voltage that varies over a time of acceleration of the charged particles; and a feedback system to detect parameters based on operation of the resonant circuit, and to control the voltage circuit based on a least one of the parameters so as to maintain a resonant condition in the resonant circuit; wherein the parameters comprises an amplitude of the voltage and a frequency of the voltage, and wherein the voltage circuit comprises an amplifier to change the amplitude of the voltage to maintain beam focusing. - View Dependent Claims (91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101)
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102. A synchrocyclotron comprising:
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a magnetic field generator; a resonant circuit comprising a variable reactive element to vary a resonant frequency of the resonant circuit; a source to provide a voltage input to the resonant circuit, the voltage input being an oscillating voltage that varies over a time of acceleration of charged particles; a feedback system to vary at least one property of the voltage input to the resonant circuit; and one or more sensors to detect that there has been a deviation from a peak resonant condition in the resonant circuit; wherein the voltage input is controlled by the feedback system based on the deviation in order to maintain the peak resonant condition. - View Dependent Claims (103, 104, 105, 106, 107, 108, 109)
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Specification