In general terms, a particle accelerator has a system to create the particles to be accelerated, a system preparing beams of many particles, an accelerating system that effectively accelerates the particle beams, a magnet system to steer the beam, an experimental facility using the particles, and finally a beam dump. In linear accelerating structures, most of the electrical power taken from the grid to operate the accelerator is used by the accelerating system itself.
Modern accelerators largely rely on superconducting cavities, cryogenically cooled to about 2 K, that are powered with radio frequency (RF) power generators to provide energy to the particle beams as they traverse a series of cavities. These are energy-intensive devices (see figure) that operate at a specific radio frequency and where only a fraction of the power extracted from the grid is effectively transmitted to the accelerated particles. In addition, the beam energy is radiated by recirculating beams and ultimately dumped and lost. As an example, the EuXFEL's superconducting RF system uses 5-6 MW for 0.1 MW of average beam power leading to a power converstion of less than 3%.
Additional information in the attached slides:
