The IOG 30D is a high-brightness focused ion beam system for contaminant free micro-machining or analysis of small areas. It uses a duoplasmatron ion source and two-lens optical column to produce a high-brightness, low-aberration spot. The source may run on pure argon (or other noble gases), nitrogen, or oxygen, and a mass filter is included in the column to separate beams of different mass/charge species. A selection of 5 apertures allows a wide current range. A gate valve in the column allows the source to be serviced without venting of the whole column.