Linacs – Protons and Ions

Even the highest-energy proton linear accelerators, with kinetic energies of order 1 GeV, are not fully relativistic. Their β = v/c values are significantly less than one. This is in stark contrast to electron linacs, in which β ≈ 1 even for energies of only a few MeV. Because of this, the dominant dynamical issues are different in proton and electron linacs. Also, the menagerie of RF structures that accelerate and manipulate protons – each tuned for a different range of β values – is very diverse.