838results about "Magnetic resonance accelerators" patented technology

A synchrocyclotron comprises 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 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.

A charged-particle beam accelerator includes an RF-KO unit for increasing the amplitude of betatron oscillation of a charged-particle beam within a stable region of resonance and an extraction quadrupole electromagnet unit for varying the stable region of resonance. The RF-KO unit is operated within a frequency range in which the circulating beam does not go beyond a boundary of the stable region of resonance, and the extraction quadrupole electromagnet unit is operated with appropriate timing as required for beam extraction so that the charged-particle beam is extracted with desired timing.

The invention relates to a cyclotron which can produce a beam of accelerated charged particles that are intended for the irradiation of at least one target (200). The inventive cyclotron consists of a magnetic circuit which essentially comprises: an electromagnet with at least two poles (1, 1′), namely an upper pole (1) and a lower pole (1′), which are disposed symmetrically in relation to a mid-plane (110) which is perpendicular to the central axis (100) of the cyclotron and which are separated by a gap (120) containing the circulating charged particles and return flux (2) in order to close the aforementioned magnetic circuit; and a pair of main induction coils (5, 5′) which are used to create an essentially-constant main induction field in the gap between poles 1 and 1′. The invention is characterised in that it comprises means of centring the above-mentioned beam, consisting of at least one pair of bucking coils (6, 7) which are supplied by an electrical source (8) and which can modulate the intensity of the main induction field produced by the main coils (5, 5′), in order to increase the intensity of the induction field in a first area of the cyclotron and to reduce the intensity of the induction field in a second area of the cyclotron, which is diametrically opposed to the central axis (100) of the cyclotron.

A particle beam therapy system using a spot scanning method includes a synchrotron, a beam transport system, an irradiation system, and a controller. A controller is configured to turn on a radio frequency electromagnetic field to be applied to an extraction system when a charged particle beam is to be supplied to the irradiation system, and turn off the radio frequency electromagnetic field to be applied to the extraction system when the supply of the charged particle beam to the irradiation system is to be blocked by means of an electromagnet provided in the beam transport system or in the synchrotron. The controller is also adapted to turn off a radio frequency acceleration voltage to be applied to an acceleration cavity in synchronization with the turning-off of the radio frequency electromagnetic field to be applied to the extraction device.