New tomographic atom probe at University of Muenster, Germany.

Currently atom probe tomography provides the highest spatial resolution compared to all other volume analysis techniques. Owing to its single atom sensitivity, it is specially suited to study nano-structured materials. Therefore, a new atom probe was installed at the Institute for Material Physics at University of Muenster, Germany, to study thin film reactions. Since the available budget was rather limited, a cost-effective non-commercial atom probe was constructed. The instrument is based on a 2D delay line detector system of 120 mm diameter. To achieve a large collecting angle and thus large volumes of analysis, a straight flight tube without a reflectron is used. This way, the flight distance may be reduced down to 160 mm. However, the variable chamber layout allows using a reflectron as an alternative. Furthermore, a laser system is implemented that delivers pulses in the 500 ps range to make possible laser-assisted evaporation of atoms. The article describes instrumental details and presents first characteristic data.