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New vistas in the realm of the small

 

TEAM 0.5 and TEAM I will be housed side by side at NCEM for some time, occupying the two multistory “silos” that until recently were the homes of the historic High-Voltage Electron Microscope and the Atomic Resolution Microscope, the most powerful microscopes in the world when NCEM was established in the early 1980s.

Ambitious as those microscopes were in their day, says TEAM’s Project Manager, Peter Denes of the Engineering Division, “when the TEAM Project was launched in 2004, it was not quite clear if the goals could even be achieved. The electron microscopy community had never done a collaborative project like TEAM before, and certainly not with full DOE project-management rigor.”

Says Denes, “Perhaps the biggest contributor to success was a series of scientific workshops that contributed to forming a converging opinion on what the next steps would be, and what would constitute success. That helped in getting everyone — if not quite on the same page — at least in the same book.”

Dahmen agrees. “This is a big jump for the microscopy community. TEAM’s success will open the door to other ambitious developments around the world.”

Dahmen suggests at least two broad categories of researchers who will benefit from the powerful new electron microscopes: experts with sophisticated microscopy problems to solve, and scientists less familiar with electron microscopy but with a particular problem for which microscopy can provide the answer.

“For example, Jim Zuo at the University of Illinois is doing studies of electron diffraction from the surface of single nanoparticles,” Dahmen says. “He sees evidence of surface contraction. But when we at NCEM do imaging of similar nanoparticles, we find that the surface is expanding. Jim looks forward to using the TEAM microscope because it can do diffraction and imaging of the same particle at the same time — a grand experiment, and the only way to solve the apparent contradiction.”

An example of a problem-solving nonspecialist, says Dahmen, might be a materials scientist who has created a new kind of nanostructure, such as a tetrapod semiconductor, and needs to know exactly where in this complex, three-dimensional shape the impurity atoms reside. “TEAM’s ability to image the structure in 3-D through tomography and its ability to do spectroscopy with single-atom sensitivity can identify each kind of atom at each position in the structure. That has never been possible before.”

The basic TEAM components of aberration correction, enhanced signal-to-noise ratio, single-atom sensitivity, and an ultrabright beam that can be used in both TEM and STEM modes — all the while manipulating the sample in the beam — are goals that until recently seemed at the very edge of technological daring. All are on track, and some have been solved ahead of schedule. The TEAM Project’s continuing success, signaled by the installation of TEAM 0.5 at NCEM, has opened the possibility of numerous future advances in electron microscopy that were barely conceivable when TEAM was launched.

The multi-institutional TEAM project represents a new kind of distributed planning and cooperation for the electron microscope community, moving beyond the limited, incremental improvements of individual investigators and harnessing the power of collaboration. Argonne National Laboratory is leading the development of the chromatic-aberration corrector in close collaboration with CEOS in Heidelberg. The University of Illinois’s Frederick Seitz Materials Laboratory is jointly developing the new piezoelectric-controlled sample stage with Berkeley Lab’s NCEM, and Oak Ridge National Laboratory is helping to optimize the new probe corrector. NCEM acts as project leader to integrate the individual components into single instruments, in close collaboration with all other TEAM partners. The TEAM Project is supported by the U.S. Department of Energy’s Office of Science.