DualEELS

DualEELS™ allows you to acquire two optimized electron energy loss spectra from different energy ranges (typically one core-loss and one low-loss) in rapid succession. This spectral recording modality helps to overcome the large dynamic range encountered in electron energy loss spectroscopy (EELS) data. When you have both the core- and low-loss signals from an identical sample area, additional processing methods become practical. These additional methods include:

• Removal of energy shift to allow accurate chemical shift measurements
• Perform absolute quantification
• Assess sample thickness and deconvolve plural scattering
• Correlate low-loss signals with core-loss features (e.g., plasmonics, band gap)

A further application of DualEELS is to extend the energy range of EELS data through the acquisition of multiple core-loss spectra.

In the DualEELS implementation from Gatan, three ultrafast electrostatic deflectors are synchronized to create the final dataset: beam blanking control down to 1 µs (Quantum) and 100 ns (Continuum); energy shift control (up to 2 kV offset with 10 µs switching time); and lateral spectrum shift control to isolate two portions of the spectrum on the detector. The fast switching results in very high collection efficiency.