Technique Selection

During the planning phase of each experiment, it is important to know what questions you want to answer, including what elements you are looking for, how much, their location, and the chemical state. When combined with information you already know, such as your sample's geometry or some major and minor elements, it is easier to select an appropriate technique that delivers answers in the shortest time possible.

• Individual spectra from a few well-chosen points – Typically gives the highest quality spectra and quantification; you can acquire data in STEM or TEM mode.

• Electron spectroscopic imaging (ESI) or contrast tuning – Powerful technique used to image one energy loss window (e.g., zero–, plasmon– or pre-carbon loss) or to scan for different phases or defects

  • Defects and changes in material properties often show strong contrast at specific energies.

• Jump-ratio imaging (2-window mapping) – Allows mapping of elements via the ratio between post-edge and pre-edge energy-filtered transmission electron microscopy (EFTEM) images; works best for finding small amounts of one element in an otherwise uniform matrix.

• Elemental mapping (3-window mapping) – Allows mapping of elements using two pre-edge EFTEM images to estimate the background under a third post-edge EFTEM image; works best for mapping elements in a general sample type.

• STEM and EFTEM spectrum imaging (N-window mapping) – Mapping and analysis via collection of a complete spectrum at each point of an image; allows superior background subtraction for standard mapping and allows advanced analysis techniques