Abstract
•New approach to optimize the performance of monochromated TEMs is proposed.•The approach is based on adjustments of already available combinations of FEI's monochromator and Gatan Imaging Filter.•TEM electron beam with 40 meV and 600 pA current is achieved.•EELS resolution of 26 meV with 40 pA probe current on a general purpose TEM is demonstrated.•Advantages for HR-TEM and EELS-STEM studies are evaluated.
The performance of a monochromated transmission electron microscope with Wien type monochromator is optimized to achieve an extremely narrow energy spread of electron beam and an ultrahigh energy resolution with spectroscopy. The energy spread in the beam is improved by almost an order of magnitude as compared to specified values. The optimization involves both the monochromator and the electron energy loss detection system. We demonstrate boosted capability of optimized systems with respect to ultra-low loss EELS and sub-angstrom resolution imaging (in a combination with spherical aberration correction).