On the detection of multiple events in atom probe tomography

Highlights: • Delay line detectors in atom probe tomography exhibit dead time and dead zone. • For both Cameca LEAP 5000 XS and 5000 XR instruments, the dead time is about 3 ns. • The dead zone evolves with the propagation of signals on the delay lines. • The dead time and dead zone can cause signal loss during multiple events detection. • The compositional and spatial accuracies can be strongly deteriorated. - Abstract: In atom probe tomography (APT), multiple events can arise as a consequence of e.g. correlated field evaporation and molecular ion dissociation. They represent challenging cases for single-particle detectors and can cause compositional as well as spatial inaccuracies. Here, two state-of-the-art atom probe microscopes (Cameca LEAP 5000 XS and 5000 XR) were used to investigate cemented tungsten carbide, which exhibits high amounts of multiple events. By advanced data analysis methods, the natural character of the multiple events, as well as the performance of the APT detectors, are assessed. Accordingly, possible signal loss mechanisms are discussed.