Rodney C. Ewing - US grants

9871177
Mansfield
Analytical electron microscopy (AEM) is critical to the characterization of metals, ceramics semiconductors, nano-composites, catalysts and geological materials. This Major Research Instrumentation proposal seeks support from NSF for the acquisition of a field emission gun analytical electron microscope (FEG-AEM). This instrument would become the primary analytical electron microscope for materials research, replacing the existing AEMs in the University of Michigan's Electron Microbeam Analysis Laboratory (EMAL). The new FEG-AEM will offer nearly two orders of magnitude higher electron beam current and a factor of three smaller electron probe than the existing instrument. This increase in beam current will mean that analyses may be performed on the nanometer length scale. The new microscope will be located in one of the custom -designed laboratories consisting of 360 square feet of temperature-controlled, low-vibration and low-field space.
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The new FEG-AEM, to be acquired under the National Science Foundation's Major Research Instrumentation program, will be the primary focus of a wide variety of materials research programs across a wide range of science and engineering disciplines. The active departments include: Materials Science & Engineering, Nuclear Engineering and Radiological Sciences, Chemical Engineering, Electrical Engineering & Computer Science, Applied Physics and Geological Sciences. Over 22 research projects, funded at a total level of over $5M, with 19 faculty, 29 graduate student researchers, and 5 undergraduate students, will be directly impacted by the new FEG-AEM. The new instrument will provide essential capabilities to the University's research programs, attract new research programs and allow the training of graduate students in advanced analytical electron microscopy.
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9911352
Essene

This award provides 67 percent partial funding support for the acquisition of a new electron microprobe to be installed in the Department of Geological Sciences at the University of Michigan. The University is committed to providing the remaining funds necessary for the acquisition. The new microprobe will be operated as part of the University of Michigan's Electron Microbeam Analytical Laboratory, ensuring adequate technical support and access for all campus researchers. The electron microprobe is an analytical tool that focuses a beam of energetic electrons on a sample surface, generating characteristic X-rays from the elements in the sample. The technique produces precise chemical composition analyses of unknown samples with good spatial resolution in the micron range. Anticipated applications at the University of Michigan include research in earth sciences, science of materials, chemistry, engineering and dentistry.
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0089645
Ewing

This three-year award for US-France cooperative research in earth sciences involves Rodney C. Ewing at the University of Michigan and Georges Calas and Thierry Allard of the Universite de Paris VI and VII. The project addresses long-term radiation effects in minerals and materials. They will study several research problems: the effects of radiation damage on chemical reactivity and surface reactivity of minerals; and radiation effects on the structure and chemical reactivity of sheet silicates, including clays that can be used as "geologic dosimeters." They will also continue radiation studies of zircon, an important mineral with potential use for disposing plutonium. The US investigator brings to this collaboration expertise in studies of radiation damage in minerals, mostly through X-ray diffraction and transmission electron microscopy. This is complemented by French capabilities in spectroscopic studies used to characterize radiation defects at the atomistic level.

This award represents the US side of a joint proposal to NSF and the French National Center for Scientific Research (CNRS). NSF will cover travel funds and living expenses for the US investigator. The CNRS will support the visits of French researchers to the United States. The collaboration will advance understanding of radiation effects in complex ceramics and materials. The research has practical importance and may contribute to better methods for storage of nuclear and radioactive waste materials.

Kesler et al
0207273


This proposal requests funding for a comprehensive study of the form of gold and its relation to the hydrothermal history of Carlin-type deposits. Most studies of these deposits have focused on macro-scale (geologic) observations with limited attention to micro-scale features. They have left a fragmented picture of the form of gold in Carlin-type deposits and how it relates to the origin and age of the deposits. The study will combine state-of-the-art high-resolution, transmission electron microscopy (HRTEM) and xray absorption, near edge structure (XANES) with more traditional surface ion mass spectrometry (SIMS) analyses to provide comprehensive mineralogical information. Work will focus on the Twin Creeks, Betze-Post-Screamer, and Meikle Carlin-type deposits, all of which have been well studied geologically. By combining observations from the atomic scale to the deposit scale, we will provide better control on mechanisms of gold transport and deposition in these deposits and on their hydrothermal history and age. Our main objectives will be to determine whether structurally bound gold in arsenian pyrite, the main host for gold in these deposits, is present as interlayers of arsenopyrite/marcasite in pyrite, and how they relate to nano-scale gold particles observed in reconnaissance studies of these deposits. This information is important because structurally bound gold might have been deposited from solutions that were not saturated with respect to native gold, thus allowing them to collect gold more efficiently during their formation. We will also evaluate whether arsenian pyrite-hosted gold and small particles of native gold are coeval or were deposited at different times. This information is needed to relate gold to the appropriate stage of mineralization and evaluate the possibility that Carlin-type deposits in Nevada were formed by several, spatially overlapping, gold-depositing events. Deposition from unsaturated solutions and formation by multiple events could also help explain why these deposits are so large. Finally, our work will relate the deposits to their geologic and tectonic setting, which is essential to exploration for ore to serve the next generation.

This grant provides support for the acquisition of a focused ion beam (FIB) workstation for multidisciplinary materials research at the University of Michigan. The FIB is an essential tool for the removal and addition of precisely controlled quantities of material from or to a wide variety of structures and devices at the micrometer and nanometer length scale. The FIB has enabled the development of innovative applications in the studies of ceramics, semiconductors, nano-composites, metals, catalysts, earth materials and biological materials. The FIB will be housed in a University-wide, centralized
user facility and will be made available to all research groups on campus, other university researchers and to industry. Immediate uses for the new dual-beam FIB include: 1) novel nano-scale engineering applications, patterning, fabrication and machining; 2) sectioning, high-resolution SEM imaging and 3D reconstruction of microstructures, site-specific specimen preparation for in-situ scanning and ex-situ transmission electron microscopy; and 3) individual, device-level modifications of semiconductor devices.

In the past ten years, over 125 research groups, from the University of Michigan, other nearby universities and industry have made use of the University materials characterization facilities. This multidisciplinary research has resulted in more than 3550 publications. Over 1100 graduate students have used the facilities for a major portion of their thesis research. Currently, 42 graduate and 16 undergraduate students are actively involved in research that will make use of the new FIB. The FIB instrument will allow the research community to more effectively pursue their studies of materials at the nanoscale, while also promoting the teaching, training and learning of the graduate and undergraduate students. Students support by the Undergraduate Research Opportunities Program (UROP) and Research Experience for Undergraduates (REU) programs are actively working on the characterization of materials. The instrument will also be used in summer research projects for minority high school students, high school teachers and young women. Once installed, the FIB will be available to a number of students in the NASA Summer High School Apprenticeship Program (SHARP) for under-represented groups.

0403732
Becker

Recent developments in surface analysis, computer simulations using quantum mechanical and empirical methods, and advanced techniques in electron microscopy now allow the accurate characterization and modeling of interface properties between nanoparticles and their immediate atomic-scale environment. These properties encompass the structural relationships between both phases, the stability of nanomaterials in their respective hosts, the chemistry in and near the interface, electron transfer mechanisms across the interface, and magnetic ordering in the nanoparticle, as well as in the near-interface region of the host matrix. These interface properties have a critical influence on the reactivity and the environmental behavior of nanoparticles. Therefore, their fate in the environment cannot be understood if only size and structure are considered. We propose to apply this combination of newly-developed experimental and theoretical capabilities to a variety of research topics that collectively focus on the important role of nanoparticle interfaces in natural systems, such as the formation of metal particles on sulfide and oxide surfaces and their incorporation into the bulk, transport of metal-bearing nanoparticles in atmospheric particulates and groundwater colloids, and to biomineralization processes.

Broader impact: This new initiative at the University of Michigan is also supported by the development of new graduate and undergraduate courses to stimulate student interest in this field. We are in the process of developing new courses in environmental geochemistry, environmental mineralogy, mineral surface science, computational methods, nuclear materials, and radioactive waste management. A number of undergraduate and graduate students from different disciplines, such as mineralogy, geology, applied physics, chemistry, nuclear engineering, materials science, and chemical engineering are expected to be involved in the projects proposed. In addition, we plan to develop a public exhibition on nanoparticles in the Museum of Natural History at the University of Michigan. The exhibit will emphasize the broad applicability of nanogeoscience to diverse areas of great public interest, such as medicine (bone and tooth growth), development of geomimetic materials, new methods for metal exploitation and mineral processing, and release and transport of environmentally hazardous materials. The museum is regularly visited, not only by university students, but also by students from the local middle and high schools, and by the general public.

Technical

This program funds a new advanced, spherical aberration-corrected high-resolution transmission electron microscope, which will be situated in the University of Michigan North Campus Electron Microbeam Analysis Laboratory. The instrument will have a resolution of 0.8 angstroms in the scanning transmission mode. It will enable researchers to determine chemistry, atomic structure, bonding characteristics, and three-dimensional imaging of materials at the true atomic level. Although it will be a critical instrument in the support of the wide range of nano-technology and energy research programs at the university, it will also operate as a resource for research institutions, both in industry and academia, in southeastern Michigan and the surrounding states. The instrument will have a 300 kV monochromated field emission gun and will have spherical aberration correction of the probe forming system. The imaging system will allow both scanning imaging and static beam imaging. In scanning imaging with a high angle annual dark field detector this microscope will allow atomic resolution imaging with atomic number contrast. Chemical analysis will be conducted by high-resolution electron energy loss spectroscopy, convergent beam electron diffraction and energy dispersive X-ray spectrometry.


Non-Technical

This program funds a new high resolution transmission electron microscope, an instrument that images extremely fine structure of material and is critical to successful nanotechnology and energy research in the University of Michigan and other research institutions in southeastern Michigan. In lieu of light, the transmission electron microscope uses a very high energy beam of electrons (300,000 volts) to probe the thin foils or particles of materials. The samples are so thin that 250 of them would be required to match the thickness of the average human hair. The imaging resolution of the new microscope will be higher than any previously located in Michigan. It will, for example, be able to image individual impurity atoms in the atomic lattices of silicon devices. The instrument will also be capable of performing chemical analyses of these samples, using what are known as spectroscopic techniques. Spectroscopy involves measuring the energy range of electrons or X-rays emitted by the sample when the high energy electron beam interacts with it. The instrument will allow researchers in the region to compete globally in research in nanotechnology, energy related materials and biological technologies. It will mean that research requiring materials characterization in Michigan will remain at the leading edge.