Linear accelerator

Device used for accelerating particles. In the context of casting inspections, linear accelerators are used to generate X-rays with typical peak energies of
> 1 MeV (mega-electron volt).

Electrons are accelerated between drift elements in linear arrangement and under alternating voltage to give off the energy at a target in the form of X-rays similar to the the principle of an X-ray tube.

Additional references:
Energy dispersive x-ray spectrometry
Wave-length dispersive x-ray spectrometry
Computed tomography
2D computed tomography
3D computed tomography