The Linear Particle Accelerator
The linear particle accelerator consists of of coaxial tubes called drift tubes connected alternatively to the terminals of a high frequency alternating voltage source.
A narrow beam of particles is generated from a source – using thermionic emission for example. The frequency of the voltage source is adjusted so that the voltage reverses polarity while the ions are traversing a tube. When this happens the ions are given an impulse in each tube and accelerated along the gap between each tube. Particles can be accelerated repeatedly by assembling many tubes in sequence and can be accelerated to very high energies using quite small potential differences in each tube.