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Next-gen electron source boosts resolution for atomic imaging

X-FEG upgrades electron microscopy capabilities for CNSI at UCLA users

by Wayne Lewis


The FEI Titan family currently offers the Titan 80-300 kV S/TEM, the world’s most powerful, commercially-available scanning transmission electron microscope. Titan is the next generation of a unique 80-300 kV range microscope with near-angstrom resolution (sub-angstrom with Cs corrector). The Titan system is poised to bring electron microscopy into a new era by expanding boundaries and assisting scientists and researchers to achieve ground-breaking results in nanoresearch. (Photo credit: Marc Roseboro/CNSI)

F or researchers probing materials and devices at the most fundamental scales using electron microscopy, the brightness and sharpness of an electron source can make a substantial difference in the quality of data collected.

UCLA investigators can now reap the benefits of increased brightness and sharpness with the FEI Titan extreme field emission gun (X-FEG), a next-generation instrument that holds the promise for higher resolution, all without making the optical system more complex. The recent addition extends the capabilities of the Titan 80-300 scanning transmission electron microscope, a resource at the Electron Imaging Center for NanoMachines (EICN), a California NanoSystems Institute at UCLA Technology Center.

In comparison to the standard Schottky FEG, the X-FEG delivers dramatically increased brightness — on the same scale as cold FEG technology, but without the tradeoffs of instabilities, reduced current and asymmetry in energy distribution. It also decreases the blurring of the probe by decreasing the effective emitting area of the source.

“We’re very excited about the X-FEG upgrade because this high-brightness source will allow us to form an angstrom-size probe even when we’re using large beam currents,” said Chris Regan, a UCLA professor of physics and CNSI member. “In other words, for most high-resolution analytical work, such as elemental mapping, having an X-FEG is as good as — or even better than — having an aberration corrector.”

The higher spatial coherence and increased resolution seen with the X-FEG come, in part, from it having a smaller source size than standard Schottky FEG technology. And the new instrument’s capability for constant emission offers the advantage of illumination current that does not fluctuate over time.

“The X-FEG upgrade will help advance my work identifying the underlying principles that lead to the degradation of nanoscale catalyst activity,” said CNSI member Yu Huang, professor and vice chair for graduate education in UCLA’s materials science and engineering department. “It’s clear that the higher signal-to-noise ratio with long-term beam stability will contribute enormously.”

Additionally, the X-FEG is outfitted with an in-source lens that compensates for low-voltage beams down to 80kV, offering better performance and higher brightness at such voltages.

An important consideration for users is the training time that will be necessary to come up to speed on a new piece of equipment. The X-FEG removes that worry altogether. Because it is outwardly similar in design to previous generations of FEG technology, no new training is required. With the X-FEG, the same processes that users are accustomed to will provide improved results.

For project consultation and proof-of-concept, prospective users should contact the EICN team at