Graz and Leoben reconstruct spectral voxels from simultaneous EELS and EDS spectrum image tomography

Transmission electron microscopy (TEM) has long been limited to supplying only projections of three-dimensional objects limiting the information that can be obtained to two dimensions.  Tilt series tomography provides 3D information, but for compositional tomography, the information is only qualitative.

Researchers at the Graz Center for Electron Microscopy and the University of Leoben in Austria utilized tilt-series scanning TEM (STEM) tomography with simultaneous low-loss EELS, core-loss EELS and EDS spectrum imaging to create three-dimension compositional maps.  Using advanced processing techniques,  they went a step further to create voxel spectra of the 3D object.  The voxel spectra allow data extraction to be perform post reconstruction open whole new avenues of analysis.  The outstanding nano-chemical reconstructions of a Al-5 wt.% Si with 50 ppm Na and 6100 ppm Yb attested to the power of the technique. 

Contributing to the success of the project were the speed and efficiency of the GIF Quantum EELS system (Model 966) and the High-Speed Spectrum Imaging package (Models 777.U1/U2/U3) from Gatan.  The group also used prototype, model based EELS and EDS software in part of the data analysis.  This prototype software will be a standard features of the new GMS 3 analysis package.