Patent ID: 7402963

Claim:
A synchrocyclotron comprising: a magnetic field generator; a resonant circuit, comprising: electrodes, disposed between magnetic poles, having a gap therebetween across the magnetic field; and a variable reactive element in circuit with the electrodes to vary the resonant frequency of the resonant circuit; and a voltage input to the resonant circuit, the voltage input being an oscillating voltage that varies over the time of acceleration of charged particles, wherein the amplitude and the frequency of the voltage are varied; said synchrocyclotron further including: an ion source for injecting charged particles into the synchrocyclotron; an extraction electrode, disposed between the magnetic poles to extract a particle beam from the synchrocyclotron; one or more sensors for detecting resonant conditions in the resonant circuit wherein the frequency of the voltage input is adjusted to maintain the resonant conditions; means for controlling the reactance of the variable reactive element and adjusting the resonant frequency of the resonant circuit to maintain the resonant conditions; a beam monitor for measuring particle beam, at least one of the voltage input, the ion source and the extraction electrode being controlled to compensate for variations in the particle beam, and wherein the oscillating voltage input is generated by a programmable digital waveform generator.