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Atomistic modelling of Atom Probe TomographyFrom Stefan Parviainens PresentationHelsinki Institute of PhysicsHow does APT Work?To cause controlledevaporation either:Apply an electric fieldIlluminate the tip with a laserTo obtain the 3D model:algorythmx,y from simple projectionz from evaporation order

S. Parviainen, Helsinki Institute of Physics RF Meeting 3rd August 2011 Roco Santiago Kern J. Appl. Phys. 105, 034913Germanium nanowires, Physorg.comED+MD ModelUsed for DC simulations, can be also used after some corrections for APT Different electric field polarity APT at low temperature (~70k)

MD Model: Easy to simulate different materials (Cu, Fe) and geometrical shapes Inter-atomic potentials give energy needed to remove atoms

S. Parviainen, Helsinki Institute of Physics RF Meeting 3rd August 2011 Roco Santiago Kern SimulationsAnimations not available (sorry)S. Parviainen, Helsinki Institute of Physics RF Meeting 3rd August 2011 Roco Santiago Kern

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Side Planar Voids Cu with Fe precipitateOther applicationsEvaporation could be used as surface treatment: Get rid of the emitters (does not work if they grow back quickly) No Field emission Higher breakdown field

S. Parviainen, Helsinki Institute of Physics RF Meeting 3rd August 2011 Roco Santiago Kern

Will be tested with the DC-Spark SystemS. Parviainen, MeVArc 2011