News and Information
FEI Titan Transmission Electron Microscope
We are excited to announce the installation of a new FEI Titan aberration-corrected TEM, as funded by the I3 internal grant competition along with matching funds (lead PI Andre Mkhoyan). This addition takes the University of Minnesota into a new realm of high-resolution characterization, both in imaging and compositional analysis. To accommodate this instrument, two rooms were combined into one and the ceiling was locally raised; a separate walled-in remote operating space was created for cases when greater instrument isolation is needed.
Technical details and capabilities of this instrument include the ability to operate at accelerating voltages ranging from 60 to 300 kV and a spherical-aberration corrector for the probe-forming lenses, yielding a STEM spatial resolution of less than 0.08 nm. The combination of an ultra-bright X-FEG source and the Super-X energy-dispersive X-ray detector system will allow elemental composition maps to be collected approximately 10 times faster than with previous systems. An electron beam monochromator and Gatan Enfinium spectrometer will enable electron energy-loss spectroscopy to be performed with an energy resolution of 0.1 eV, allowing unparalleled access to structural and bonding information and the capability to determine elemental composition at atomic resolution.
The growth and modernization of our TEM enterprise also leads to a heightened need for equipment to handle specimen and specimen holder cleaning for high-resolution work. As announced in our last newsletter, a grant-in-aid award to Prof. Mkhoyan has enabled the purchase of an advanced plasma cleaner for transmission electron microscopy specimens and specimen holders. This augments a 10-year old system that has experienced substantial downtime with increasing age. The new system will provide greater capacity and the additional ability to mix gases for more precisely controlled chemical action. Please contact Jason Myers for more information about the new systems and/or to discuss your TEM needs.
Nicolet iS50 FT-IR Spectrometer
A new FT-IR spectrometer has been installed to replace the old Nicolet Magna 750 spectrometer. It is superior in many aspects to the Magna 750. The new spectrometer is equipped with MCT and DLaTGS detectors, a high-intensity IR source, a white light source that can be used for near IR measurements, and a built-in attenuated total refection (ATR) with a diamond crystal. Transmission, specular and diffuse reflections and ATR measurements can be conducted on the main bench. We also acquired a multi-bounce ATR accessory with ZnSe and Ge crystals. The multi-bounce ATR allows IR lights to interact with the sample surface for more than 10 times, increasing the possibility of detecting low-concentration species. The existing Continuum FT-IR microscope is fully compatible to this spectrometer and is used to conduct transmission, reflection and ATR measurements. Please contact Bing Luo for more information and use of this instrument.
Cryogenic Scanning Electron Microscopy System (cryo-SEM)
The new system will upgrade and improve cryoSEM capabilities in a growing range of applications and replace the Hitachi S-900 FEGSEM and ancillary hardware for specimen preparation and vacuum introduction currently in use in our Hasselmo Hall facility. The majority of the work performed with our current systems has involved cross-sectional imaging of liquid-applied coatings (e.g., latex). Here the concept is to see all ingredients, both solid and liquid, by fast freezing to solid state then fracturing the coating under vacuum, and keeping at cryogenic temperatures (i.e., solid) during electron-beam based imaging. For information on using any of our cryo-SEM systems in the future, please contact staff members Chris Frethem or Jake Warner