Focused Ion Beam
An FEI Helios instrument has been installed in NNL's Central Laboratory. It is currently capable of handling trace active samples. An airlock and sputtered material shields are fitted and following fully active commissioning in 2015 the instrument will be able to handle more highly irradiated structural materials and fuels.
This instrument combines the imaging and analysis capabilities of an SEM with the ability to use an ion beam as a nano-to-micron scale “scalpel”, thus allowing cross-sectioning of samples and preparation for analysis in the Transmission Electron Microscope or Atom Probe Tomography.
Cross-sectioning is destructive so work with highly radioactive material will be carefully assessed to minimise issues with deposition of active material within the instrument. Examples of applications include examination of stress corrosion cracking and oxidation and preparation of non-conductive materials not suitable for electropolishing.
The very small size of the TEM and APT samples means that they can more easily be transported to universities or other research facilities, although NNL can currently provide access to its active TEM (JEOL 2100 fitted with 80mm2 Oxford Instruments EDX detector) and will be installing a FEGTEM as part of the NNUF facility. The current TEM is capable of 5-10nm spatial resolution for the analysis of irradiated samples and is typically used to characterise irradiated cladding. An electron energy loss spectroscopy (EELS) upgrade (Gatan Quantum 965ER) is in progress.