A particle accelerator comprising a waveguide comprising a series of acceleration cells. The series of acceleration cells comprise an input acceleration cell configured to accelerate a beam of electrons along the central axis of the cells. A source of electrons is configured to input a beam of electrons into the input acceleration cell and a magnet arrangement is configured to prevent electrons that have deviated from the beam of electrons from hitting the source of electrons.

A high gradient linear accelerating structure can propagate high frequency waves at a negative harmonic to accelerate low-energy ions. The linear accelerating structure can provide a gradient of 50 MV/m for particles at a β of between 0.3 and 0.4. The high gradient structure can be a part of a linear accelerator configured to provide an energy range from an ion source to 450 MeV/u for .sup.12C.sup.6+ and 250 MeV for protons. The linear accelerator can include one or more of the following sections: a radiofrequency quadrupole (RFQ) accelerator operating at the sub-harmonic of the S-band frequency, a high gradient structure for the energy range from ˜45 MeV/u to ˜450 MeV/u.

A system for monitoring intensity of a particle beam can include one or more radio-frequency (RF) detectors coupled to a signal analyzer that can be placed outside the radiation field of the particle beam. Each RF detector can include a gas-filled RF cavity coupled to one or more gas-filled waveguides. The signal analyzer can self-calibrate before the particle beam is turned on for determining one or more absolute intensities of the particle beam when the particle beam is present.

In an example, a synchrocyclotron includes a particle source to provide pulses of ionized plasma to a cavity; a voltage source to provide a radio frequency (RF) voltage to the cavity to accelerate particles from the plasma column outwardly; and an extraction channel to receive a beam of particles from the cavity for output from the particle accelerator. The particle source is configured to control pulse widths of the ionized plasma in order to control an intensity of the beam of particles. This example synchrocyclotron may include one or more of the following features, either alone or in combination.

Disclosed herein is a waveguide for use in a linear accelerator. The waveguide comprises cells arranged to receive a beam of charged particles therethrough along a particle path, and is configured to receive an electromagnetic field from a source of electromagnetic radiation. A plurality of the cells are individually switchable cells, with each individually switchable cell comprising a respective switch configured to adjust the supply of electromagnetic radiation to the individually switchable cell.

A high gradient linear accelerating structure can propagate high frequency waves at a negative harmonic to accelerate low-energy ions. The linear accelerating structure can provide a gradient of 50 MV/m for particles at a β of between 0.3 and 0.4. The high gradient structure can be a part of a linear accelerator configured to provide an energy range from an ion source to 450 MeV/u for .sup.12C.sup.6+ and 250 MeV for protons. The linear accelerator can include one or more of the following sections: a radiofrequency quadrupole (RFQ) accelerator operating at the sub-harmonic of the S-band frequency, a high gradient structure for the energy range from ˜45 MeV/u to ˜450 MeV/u.

A linear accelerator having multiple cavities along a beamline that is powered by a pair of distribution waveguide manifolds with a sequence of feed arms connecting the manifolds to the cell sections and a single RF feed is described herein. The distribution waveguide manifolds are connected to the cell sections so that alternating pairs of cell sections are connected to opposite distribution waveguide manifolds. The individual cavities are individually optimized according to the electron speed along the beamline. The geometry of the cell junctions and connecting channels between the manifolds and cavities can be individually optimized along the beamline as well and can include a serpentine configuration to provide a consistent RF channel length between the manifolds and differing cavities. Methods of designing the linear accelerator and fabricating the accelerator are also provided.

An example particle therapy system may include: a synchrocyclotron to produce a particle beam; a scanner to move the particle beam in one or more dimensions relative to an irradiation target; and an energy degrader that is between the scanner and the irradiation target. The energy degrader may include multiple plates that are movable relative to a path of the particle beam, with the multiple plates each being controllable to move while in the path of the particle beam and during movement of the particle beam. An aperture may be between the energy degrader and the irradiation target. The aperture being may be to trim the particle beam prior to the particle beam reaching the irradiation target.

A system for monitoring intensity of a particle beam can include one or more radio-frequency (RF) detectors coupled to a signal analyzer that can be placed outside the radiation field of the particle beam. Each RF detector can include a gas-filled RF cavity coupled to one or more gas-filled waveguides. The signal analyzer can self-calibrate before the particle beam is turned on for determining one or more absolute intensities of the particle beam when the particle beam is present.

An example particle therapy system may include: a synchrocyclotron to produce a particle beam; a scanner to move the particle beam in one or more dimensions relative to an irradiation target; and an energy degrader that is between the scanner and the irradiation target. The energy degrader may include multiple plates that are movable relative to a path of the particle beam, with the multiple plates each being controllable to move while in the path of the particle beam and during movement of the particle beam. An aperture may be between the energy degrader and the irradiation target. The aperture being may be to trim the particle beam prior to the particle beam reaching the irradiation target.