Atomic level EELS mapping using high energy edges in DualEELS mode

Over the past few years, with the advancements in aberration-corrected transmission electron microscopy, the spatial resolution in scanning transmission electron microscopy (STEM) has been enormously improved. Such improvements that are the results of the reduction of the probe size and the dramatic increase of the probe current lead to the capability of acquiring high resolution elemental and chemical maps using electron energy loss spectroscopy (EELS). Atomic level EELS maps can now be easily acquired and their acquisition time is to a large part related to the speed of the EELS spectrometer. The introduction of fast EELS spectrometers such as the GIF Quantum® system has dramatically improved the information that can be obtained from an EELS spectrum imaging (SI) dataset. Now, EELS maps can be acquired at over 1,000 spectra per second which allows full advantage of the increased probe current available in an aberration probe corrected microscope to be realized. In addition the lens system present in the GIF Quantum system, with the capability to correct the aberration up to the 5th order, leads to the ability of using high collection angles allowing more signal to enter the spectrometer while maintaining the energy resolution.

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