For more than 40 years, Arizona State University has been known for expanding the boundaries of electron microscopy and research in materials and the life sciences. Now it has taken a leap forward into atomic level research.
In 2012, the university opened the Southwestern Center for Aberration Corrected Electron Microscopy (SW-ACEM), a premier microscopy facility on par with top government research laboratories. Ultimately, through the use of aberration corrected STEM and TEM, researchers will gain a better understanding of the behavior of materials at their most essential level, and will view the very atoms that comprise their samples.
Part of ASU’s Eyring Materials Center, SW-ACEM is home to a JEOL JEM-ARM200F atomic resolution transmission electron microscope. The microscope is located in an underground bay in a very high stability new building that shields the instrument from all environmental interferences. It can be accessed only through a door from a separate control room for remote operation.
Dr. Ray Carpenter, Principal Investigator and Professor, hosted an open house during the week of the August 2012 Microscopy & Microanalysis conference in Phoenix. It was106 degrees outside, and a haboob dust storm was soon to rumble across the desert, but inside the 22” concrete/block walls, there was an impermeable sense of cool and quiet as the ARM200F revealed the atomic structure and chemistry of the sample it was imaging.
The development of this facility is one of Professor Carpenter's major achievements in his long career in microscopy. It took six years to write the proposals, acquire the instrumentation, and design and construct the building.
During the tour, Professor Carpenter emphasized the 41” thick concrete foundation of the building, with plastic-coated rebar to avoid stray circulating currents, and the 22” block walls, to suppress vibration and acoustic disturbances and increase thermal stability. The room housing the ARM200F has been further enhanced with a Hydro Radiant Panel System from JEOL to maintain a steady temperature in the room.
Meanwhile, the TEM displayed a live image on a monitor, showing each individual atom column of the sample inside the electron microscope. Professor Carpenter noted that the live image of atoms had retained its stability over time, with very little degradation.
It was exactly as he had stated, during the dedication of the building on February 29, 2012. "When I came to ASU, Leroy Eyring was still here and John Cowley was the director of our Facility. All during this time ASU was building its reputation, concentrating mainly on the geometric arrangement of atoms in crystals. Instruments were not yet available for direct chemical identification of atoms and bonding with atomic resolution.
So now we're broadening our research enormously by using new instrumentation to go into atomic level identification of chemical identity and bonding states of atoms in a wide variety of materials, and we have the resolution to do that in amorphous materials as well as crystals. This new building plays a major part in that. Data collected this morning shows the stability of an image within about a quarter-atom diameter over a ten-minute period collecting a spectrum image. That's the kind of stability you need to do this work, and that's what the building, along with the microscopes, is designed to do."
ASU students from Materials, Chemistry, Physics, and Geology are using the new SW-ACEM now for research, and it is also playing an increasing role in ASU teaching at several levels. In addition to direct demonstration to students, the digital information output has been streamed directly to lecture halls for projection using the internet. Atomic resolution images and nanospectra are demonstrated in real time for both university students and K-12 science classes. This technique is particularly useful for demonstrating abstract concepts such as Ronchigrams, coma correction, and stigmation that are complicated to envision without direct real-time examples.
SW-ACEM is a multiuser facility, with researchers from other universities and industrial clients using the aberration corrected microscopes. Two PhD level scientist/engineers on staff highly experienced in both aberration corrected microscopy and materials assist microscope users to obtain their research objectives.
There is also a large outreach program within the LeRoy Eyring Center for Solid State Science. The Winter School on High Resolution Electron Microscopy is part of the outreach effort. It is conducted every January and attracts students from all parts of the USA and some from overseas. The ARM was first used in the school last year and will play an increasing role this year and in the future, because aberration corrected EM is assuming a central role in microscopy research and applications. Demonstrations of atomic resolution imaging and energy loss spectroscopy using the ARM are also provided for numerous visiting K-12 and science teacher groups throughout the year.