Optimisation of specimen temperature and pulse fraction in atom probe microscopy experiments on a microalloyed steel.

This paper details the effects of systematic changes to the experimental parameters for atom probe microscopy of microalloyed steels. We have used assessments of the signal-to-noise ratio (SNR), compositional measurements and field desorption images to establish the optimal instrumental parameters. These corresponded to probing at the lowest possible temperature (down to 20K) with the highest possible pulse fraction (up to 30%). A steel containing a fine dispersion of solute atom clusters was used as an archetype to demonstrate the importance of running the atom probe at optimum conditions.