A focused ion beam device is described. The focused ion beam device includes an ion beam column including an enclosure for housing a gas field ion source emitter with an emitter area for generating ions, an electrode for extracting ions from the gas field ion source emitter, one or more gas inlets adapted to introduce a first gas and a second gas to the emitter area, an objective lens for focusing the ion beam generated from the first gas or the second gas, a voltage supply for providing a voltage between the electrode and the gas field ion source emitter, and a controller for switching between a first voltage and a second voltage of the voltage supply for generating an ion beam of ions of the first gas or an ion beam of ions of the second gas.