Nuclearization of atom probe tomography and the workflow analysis: Atomic-scale characterization of neutron irradiated materials.

Atom Probe Tomography (APT) enables access to compositional, morphological and structural information from microstructural features at the atomic scale. This information is especially important on neutron-irradiated material to characterize chemical composition variations around point defect clusters or grain boundaries.

The LECI hotlab facility at CEA Saclay in France, is equipped with a nuclearized APT in combination with APT specimen preparation for neutron-irradiated materials. The APT analysis needs a needle shape specimen (with curvature radius <50nm) by using either electro-polishing or Focused Ion Beam (FIB).

This work is a major stake for CEA/DRMP (Material and Physico-chemical Research Department) that includes several steps, such as the manufacturing of a glove box, the instrumental nuclearization of the APT in association with the nuclear safety and radiation protection. This project includes also the nuclearization of sample preparation devices, integrated in shielded glovebox/cells, that is designed to prepare massive electropolished or FIB samples from radioactive material. The transfer and activity control between each unit from sample preparation devices to APT were also optimized in other to increase the final analyses yield. The work presented here will highlight the impacting factors when designing a nuclearized APT, as well as the limitations and difficulties when undertaking such a project.

The first analyses of radioactive material has been performed and several studies are already planned on different nuclear irradiated materials such as fuel cladding, reactor vessel...  Some examples of such APT analysis will be presented.