On-axis energy analysis of69Ga+, Ga2+, and Ga 2 + ions emitted from a gallium liquid metal ion source

On-axis energy distribution measurements of 3 ionic species emitted from a gallium liquid metal ion source are reported. Voltage deficits, FWHM energy spreads, angular intensities and chromatic angular intensities are presented and compared with other published work. Ga⁺ deficit variations with beam current and temperature are discussed in detail. Ga₂⁺ FWHM and deficit changes with source operating conditions are accounted for by a model of droplet fragmentation.