An ion implanter, including an ion source and extraction system, arranged to generate an ion beam at a first ion energy, and a linear accelerator, arranged to accelerate the ion beam to a second ion energy, wherein the linear accelerator comprises a plurality of acceleration stages coupled to receive a plurality of RF signals from a plurality of power assemblies, respectively. The linear accelerator may be configured wherein at least one stage of the plurality of acceleration stages is coupled to: reversibly connect to a first power assembly, comprising a resonator that contains a resonator enclosure, the first power assembly generating a first RF signal at a first frequency; to disconnect from the first power assembly; and to connect to a second power assembly, generating a second RF signal at a second frequency, greater than the first frequency, while not changing the resonator enclosure.