Method for an accurate calibration of the flight-time-focused time-of-flight atom probe

A method is devised to determine accurately the flight-path constant, the time-delay constant, and the pulse factor for the flight-time-focused time-of-flight atom probe field ion microscope. Using these constants, masses of ions can be determined routinely to the accuracy of ∼0.005 to 0.06 u for ions of mass 1–100 u with our present system. This system has a flight-path length of ∼250 cm. It is equipped with a time digital converter of 1-ns time resolution and supporting measuring instruments of very modest specifications. The accuracy of the system can be further improved by having better supporting instruments. The principle of this calibration method can be easily adopted for calibrating other types of mass spectrometers.