Enhancement of collimated low-energy broad-beam ion source with four-grid accelerator system

An application of a four-grid ion acceleration system for generating highly collimated low-energy (<1.5 keV) ion beams is presented. The four-grid system offers significantly reduced beam divergence angles for practical low-energy source designs compared to current two- and three-grid systems. Ion beam divergence of the entire beam envelope has been reduced to less than 2° at 250 and 750 eV. Results are also compared with a conventional three-grid system.