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 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.