A method of patterning lithographic substrates that includes using a free electron laser to generate EUV radiation and delivering the EUV radiation to a lithographic apparatus which projects the EUV radiation onto lithographic substrates. The method further includes reducing fluctuations in the power of EUV radiation delivered to the lithographic substrates by using a feedback-based control loop to monitor the free electron laser and adjust operation of the free electron laser accordingly, and applying variable attenuation to EUV radiation that has been output by the free electron laser in order to further control the power of EUV radiation delivered to the lithographic apparatus.

Embodiments of the disclosed system and method provide for generating a multiple-energy X-ray pulse. A beam of electrons is generated with an electron gun and modulated prior to injection into an accelerating structure to achieve at least a first and second specified beam current amplitude over the course of respective beam current temporal profiles. A radio frequency field is applied to the accelerating structure with a specified RF field amplitude and a specified RF temporal profile. The first and second specified beam current amplitudes are injected serially, each after a specified delay, in such a manner as to achieve at least two distinct energies of electrons accelerated within the accelerating structure during a course of a single RF-pulse. The beam of electrons is accelerated by the radio frequency field within the accelerating structure to produce accelerated electrons which impinge upon a target for generating Bremsstrahlung X-rays.

A linac-based X-ray system for cargo scanning and imaging applications uses linac design, RF power control, beam current control, and beam current pulse duration control to provide stable sequences of pulses having different energy levels or different doses.

A particle accelerator for creation of a bunched particle beam and a method for the operation of such a particle accelerator are provided, wherein the particle accelerator includes an HF source and a directional coupler for splitting HF power of the HF source of an HF side into at least a first and a second HF power coupler of a cavity side for coupling in the HF power into at least one accelerator cavity. A. non-reciprocal phase shifter is inserted on the cavity side between the directional coupler and the second HF power coupler, and an HF load is connected on the HF side to the directional coupler, where the non-reciprocal phase shifter is configured to pass a reflected HF wave of the second HF power coupler with phase delay in the direction of the directional coupler in such a way that a destructive interference of the reflected HF waves of the first and second power couplets occurs in the directional coupler in the direction of the source on the HF side.

A particle accelerator can include a first waveguide portion and a second waveguide portion. The first waveguide portion can include a first plurality of cell portions and a first iris portion that is disposed between two of the first plurality of cell portions. The first iris portion can include a first portion of an aperture such that the aperture is configured to be disposed about a beam axis. The first waveguide portion can further include a first bonding surface. The second waveguide portion can include a second plurality of cell portions and a second iris portion that is disposed between two of the second plurality of cell portions. The second iris portion can include a second portion of the aperture. The second waveguide portion can include a second bonding surface.

A system has a linear accelerator, ion pump and a compensating magnet. The ion pump includes an ion pump magnet position, an ion pump magnet shape, an ion pump magnet orientation, and an ion pump magnet magnetic field profile. The compensating magnet has a position, a shape, an orientation, and a magnetic field profile, where at least one of the position, shape, orientation, and magnetic field profile of the compensating magnet reduce at least one component of a magnetic field in the linear accelerator resulting from the ion pump magnet.

A linac-based X-ray system for cargo scanning and imaging applications uses linac design, RF power control, beam current control, and beam current pulse duration control to provide stable sequences of pulses having different energy levels or different doses.

A Hybrid (SW+TW) Linear Acellerator is disclosed having high beam efficiency and broad energy regulation that is useful for security inspection, non-destructive testing, radiotherapy, and electron beam irradiation of objects. The Hybrid Linear Accelerator (LINAC) provides superior energy regulation, and includes a reversed RF power distribution which substantially improves RF power utilization, thereby eliminating need for an output RF load, and ensuring broad electron beam energy regulation operating in a broad range of input RF power, thereby efficiently running at a variety of input electron beam current intensities at high efficiency. The Hybrid LINAC may be equipped with a fast and/or slow phase shifter and/or a power regulator having a phase shifter and a current regulator, while operating much more efficiently than known LINACS. The Hybrid LINAC permits efficient operation without an external magnetic field, thereby avoiding use of a power-consuming solenoid, consequently reducing cost of production, operation, and maintenance.

Described is a method of determining whether repair or replacement of an electron gun of a radiotherapy device should be scheduled. The radiotherapy device comprises a linear accelerator and is configured to provide therapeutic radiation to a patient. The radiotherapy device comprises a vacuum tube comprising the electron gun, a waveguide configured to accelerate electrons emitted by the electron gun toward a target to produce said radiation. The radiotherapy device comprises also comprises a current sensor, the current sensor being configured to provide signals indicative of current supplied to the electron gun. The method comprises receiving a current value, processing the current value, and based on the processing of the current value, determining whether repair or replacement of the electron gun should be scheduled. Processing the current value comprises determining whether the current value meets at least one threshold criterion, and determining whether the current value has changed by at least a threshold amount in a particular time period.

An accelerating cavity includes an electrically conductive cylindrical housing and a plurality of cells that are made of a dielectric material and have openings in respective central portions of the cells through which charged particles are allowed to pass. The cells are arranged inside the housing while being aligned in the axial direction of the central axis of the housing, and sandwiched by the housing in the axial direction of the central axis to be immobilized. The housing has grooves provided on portions thereof that support the respective cells and each having a depth that is one fourth of the wavelength of radio frequency waves for the acceleration mode that propagate through the cells.