Brightness Limits in Linear Ion Accelerators

Abstract

Radio-frequency linear ion accelerators are attractive for high beam-current applications over a large energy range (Jameson, 1986). High peak currents are possible because relatively strong focusing can be provided, and the half-integer and integer resonances that severely limit the beam intensity in circular machines are not present in linacs. Furthermore, because there are no fundamental restrictions that limit the duty factor in linear accelerators, high average beam currents also can be delivered. Nevertheless, limits to the beam current do exist and undesired effects of the space-charge forces, which we are only beginning to understand, can cause serious degradation of the brightness. These effects usually occur at the low-velocity end of the linac, where beam density is highest, focusing is weakest, and bunches are formed from the injected dc beam.KeywordsCharge RedistributionUniform BeamEmittance GrowthHigh Current BeamPlasma PeriodThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.