Ion energy spread and current measurements of the rf-driven multicusp ion source

Axial energy spread and useful beam current of positive ion beams have been carried out using a radio frequency (rf)-driven multicusp ion source. Operating the source with a 13.56 MHz induction discharge, the axial energy spread is found to be approximately 3.2 eV. The extractable beam current of the rf-driven source is found to be comparable to that of filament-discharge sources. With a 0.6 mm diameter extraction aperture, a positive hydrogen ion beam current density of $\text{80 \hspace{0.5em}}{\mathrm{mA/cm}}^2$ can be obtained at a rf input power of 2.5 kW. The expected source lifetime is much longer than that of filament discharges.