The atom probe field ion microscope allows single atom identification by combining a field ion microscope with a time‐of‐flight mass spectrometer. A circuit is described which provides time resolution of ±10 nsec in an interval of 100 &mgr;sec for up to eight particles arriving at the detector in any one field evaporation pulse cycle. The duty cycle of the instrument is limited only by the data recording system. The ±10 nsec resolution allows identification of species separated by one mass unit under the worst case conditions of high atomic weight and high accelerating voltage.