Ionization of liquid gallium coated on a tungsten field‐ion tip was investigated using a magnetic‐sector atom probe. For the first time, both the energy distribution of ionized Ga and its critical energy deficit with respect to a tip potential were measured as a function of field and tip temperature. Without heating the gallium, a stable Ga+ion current of up to 10 &mgr;A was obtained from a small surface area of a tip with an energy distribution of less than 12 eV FWHM.