Beam extraction from a compact Ku-band electron cyclotron resonance ion source with double resonance modes

Beam extraction tests were carried out using a new compact Ku-band electron cyclotron resonance (ECR) ion source. In the case of a single rf frequency operation, a B2 zone can contribute for increase of single and low charged state ion beams when the gas flow rate is relatively higher than that for the basic ECR mode. The scheme seems, however, not so effective for the pro duction of multicharged state ion beams. A double frequency heating (12 and 14 GHz) is, on the other hand, effective for increase of extracted ion cur rent when the rf power is injected into the chamber from both the axial and the radial ports, as succeeded at the LBL experiment. (C) 2000 American In stitute of Physics. [S0034-6748(00)66302-5].