Radio-frequency quadrupole
A radio-frequency quadrupole is a linear accelerator component generally used at low beam energies, roughly 50keV to 3MeV. It is similar in concept to a quadrupole mass analyser but its purpose is to accelerate a single-species beam.
at Michigan State University.
The RFQ is a combined-function component that both accelerates and focuses the beam of charged particles.
Invented by Soviet physicists I. M. Kapchinsky and Vladimir Teplyakov in 1970, the RFQ is used as an injector by major laboratories and industries throughout the world for radiofrequency linear accelerators.