A group of researchers from several academic departments at South Dakota School of Mines and Technology, led by Principal Investigator Dr. Phil Ahrenkiel, assistant professor of nanoscience and nanoengineering, have been awarded funding for a new transmission electron microscope (TEM).
The award of $699,000 for the purchase of the new equipment was made by the National Science Foundation (NSF) through its major research instrumentation program. The instrument will be housed within the School of Mines' Engineering and Mining Experiment Station (EMES), which was awarded a state-of-the-art scanning electron microscope (SEM) in 2006 through the same NSF program.
Scientists from many disciplines use TEM to examine structure on the nanometer length scale (one nanometer = 10-9 meters). An electron beam with up to 200,000 volts of electric potential is formed in the TEM, projected down a high-vacuum column and focused with electromagnetic lenses to "illuminate" a small area of sample material with the electron radiation. A projection image of the sample is formed from the transmitted electrons by additional lenses below the sample. The image can be magnified by a factor as large as 1 million times, revealing details down to the atomic scale.
Like all matter, electrons have a dual particle/wave nature, so electron scattering gives rise to diffraction effects. Diffraction is a primary limitation on the resolution of both light and electron microscopes, but in the TEM, diffraction also reveals details about the crystal structures of materials being investigated.
"SEM and TEM are essential characterization techniques for nanomaterials research," Ahrenkiel said. "With the acquisition of the new TEM, the EMES will now have the core tools needed to serve as an electron-microscopy hub for South Dakota and the northcentral states region."
The request for the instrument was made to the NSF to promote graduate research programs in materials science and geological, chemical, biochemical, and environmental engineering. Co-principal investigators on the proposal are Dr. Michael Terry, assistant professor, geology and geological engineering; Dr. Rajesh Sani, assistant professor, chemical and biological engineering; Dr. Rajesh Shende, assistant professor, chemical and biological engineering; and Dr. Haiping Hong, research scientist III, materials and metallurgical engineering. The instrument will be available for graduate students to receive technical training and gain expertise in the analysis of nanomaterials.
