Abstract: Disclosed is an RF window. The RF window comprises a first and a second cavity and a plate of dielectric material positioned there between. At least one of the first and second cavities comprises a taper, beginning at the plate, such that the at least one of the first and second cavities reduces in diameter in a direction away from the plate.

Abstract: A reusable joint for a medical linac, a reusable CF choke flange for a medical linac, a linac and a method for forming a reusable joint for a medical linac are disclosed. The reusable joint comprises a CF choke flange, a CF cover flange and a gasket. The CF choke flange comprises a first waveguide aperture, a choke groove and a first CF groove comprising a first knife-edge, wherein the choke groove is disposed radially inwards from the first CF groove on the CF choke flange. The CF cover flange comprises a second waveguide aperture aligned with the first waveguide aperture and a second CF groove comprising a second knife-edge and aligned with the first CF groove. The gasket is disposed between and in contact with the first CF groove and the second CF groove.

Abstract: 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.

Abstract: Disclosed here is an RF source comprising first, and second RF pulse generators arranged to deliver RF pulses for a particle accelerator and a controller arranged to control the first and second RF pulse generators to generate pulses sequentially.

Abstract: A radiotherapy apparatus adapted for use with a Magnetic Resonance Imaging (MRI) system, the radiotherapy apparatus comprising a linear accelerator, the linear accelerator including an electron source. In the linear accelerator electrons which are introduced by the source are accelerated to impact on a target and produce a beam of radiotherapeutic radiation. The linear accelerator has an accelerator waveguide within which the electrons are accelerated and an external waveguide enclosure; this enclosure extends substantially continuously over the accelerator waveguide.

Abstract: A method of determining a design of a transmission waveguide, the method comprising: providing a system comprising a transmission waveguide connected at a first end thereof to an RF source; generating an electromagnetic field in the system by application of RF energy of a harmonic frequency of the RF source to the transmission waveguide; determining whether a reference location in the RF source meets a requirement relating directly or indirectly to an electromagnetic field in the RF source; and if the requirement is met, outputting the current design of the transmission waveguide as its design.

Abstract: A particle accelerator comprises a waveguide configured to accelerate a beam of electrons along an acceleration path. A diversion channel is configured to convey a beam of electrons along a diversion path. A first magnet arrangement is configured to, at a first location, direct electrons from the acceleration path to the diversion path. A second magnet arrangement is configured to, at a second location, direct electrons from the diversion path to the acceleration path.

Abstract: A reusable joint for a medical linac, a reusable CF choke flange for a medical linac, a linac and a method for forming a reusable joint for a medical linac are disclosed. The reusable joint comprises a CF choke flange, a CF cover flange and a gasket. The CF choke flange comprises a first waveguide aperture, a choke groove and a first CF groove comprising a first knife-edge, wherein the choke groove is disposed radially inwards from the first CF groove on the CF choke flange. The CF cover flange comprises a second waveguide aperture aligned with the first waveguide aperture and a second CF groove comprising a second knife-edge and aligned with the first CF groove. The gasket is disposed between and in contact with the first CF groove and the second CF groove.

Abstract: Disclosed herein is a waveguide cell having a helical cavity. The waveguide cell has a central axis and a cavity having a transverse cross section whose rotational position about the central axis varies along the central axis. There is also disclosed a method a determining the shape of a waveguide cell.

Abstract: 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.

Abstract: Disclosed is an RF window. The RF window comprises a first and a second cavity and a plate of dielectric material positioned there between. At least one of the first and second cavities comprises a taper, beginning at the plate, such that the at least one of the first and second cavities reduces in diameter in a direction away from the plate.

Abstract: A radiotherapy apparatus adapted for use with a Magnetic Resonance Imaging (MRI) system, the radiotherapy apparatus comprising a linear accelerator, the linear accelerator including an electron source. In the linear accelerator electrons which are introduced by the source are accelerated to impact on a target and produce a beam of radiotherapeutic radiation. The linear accelerator has an accelerator waveguide within which the electrons are accelerated and an external waveguide enclosure; this enclosure extends substantially continuously over the accelerator waveguide.

Abstract: A linear accelerator is disclosed, having a series of interconnected cavities through at least some of which an rf signal and an electron beam are sent, comprising at least one variable coupler projecting into the a cavity of the series, a control apparatus adapted to interpret an electrical signal from the coupler and derive diagnostic information as to the electron beam therefrom, wherein the control apparatus is further adapted to vary the interaction of the at least one coupler with the rf signal in dependence on the diagnostic information. Thus, the accelerator properties can be adjusted by encouraging or inciting an Higher-Order Mode (“HOM”) having a desired effect such as bunching and/or deflecting. The coupler could be rotateable, and partially or fully retractable, to allow its influence to be adjusted and/or for it to be removed from service when not needed.

Abstract: A linear accelerator is disclosed, having a series of interconnected cavities through at least some of which an rf signal and an electron beam are sent, comprising at least one variable coupler projecting into the a cavity of the series, a control apparatus adapted to interpret an electrical signal from the coupler and derive diagnostic information as to the electron beam therefrom, wherein the control apparatus is further adapted to vary the interaction of the at least one coupler with the rf signal in dependence on the diagnostic information. Thus, the accelerator properties can be adjusted by encouraging or inciting an Higher-Order Mode (“HOM”) having a desired effect such as bunching and/or deflecting. The coupler could be rotateable, and partially or fully retractable, to allow its influence to be adjusted and/or for it to be removed from service when not needed.