Enviromental Scanning Electron Microscope (ESEM)
Installed in the fall of 2001, this instrument has a wide range of electron scanning capabilities. Just like a conventional scanning electron microscope (SEM), the Environmental SEM, produces images of surface features at very high magnifications (100X to 100,000X). The ESEM however does not require high vacuum in the specimen chamber, allowing us to observe samples (even wet ones) under conditions more similar to those in which the sample existed in nature (“environmental” conditions). Operated in ESEM mode it is possible to observe specimens in hydration states extending to 100%. Because conductive coatings are not required, the ESEM is also of great interest for looking at visible light generated in crystals by the electron beam (cathodoluminescence). Standard “high vac” SEM operation is also an option. Detectors include a light element EDS detector and a Gatan cathodoluminescence detector with RGB color filtration for observation of near-true luminescent color. An EBSD detector was installed summer 2006.
Examples of cathodoluminescence of zircon grains taking using the ESEM.
Frelinger, S. N., Ledvina, M. D., Kyle, J. R., & Zhao, D. (2015). Scanning electron microscopy cathodoluminescence of quartz: Principles, techniques and applications in ore geology. Ore Geology Reviews, 65(PART 4), 840-852. Zhao_Frelinger2015
Like the SEM, the ESEM accommodates a wide range of sample types. Small rock chips, grain mounts, and thin sections are all possible.