The microprobe provides elemental information, either qualitative or quantitative, about a solid substance, such as a rock, crystal, glass, alloy or thin film. The analytical resolution is about a micron and quantitative uncertainty is typically 1-2% relative. Scanning resolution is on the order of tens of nanometers.
Information derived is typically a quantitative elemental analysis, an image displaying contrast between phases (electron backscatter), or elemental (X-ray) maps.
Our JEOL 8500F field emission electron microprobe was installed in 2008. The field emission (FE) electron gun provides a very small probe, on the order of one-half to one-tenth that produced by a conventional tungsten filament, even at high beam currents. Additionally, the FE gun is capable of very high beam currents, even at low accelerating voltage. Advantages include better light element analyses and faster mapping of low abundance elements. In addition, a cold finger reduces contamination during light element analysis.
The microprobe is equipped with five wavelength dispersive X-ray spectrometers, and a Thermo Noran silicon drift energy dispersive X-ray spectrometer. The probe also routinely acquires cathodoluminescence and secondary and back scatter electron images.
Our microprobe is used extensively by F. Nick Foit and his colleagues for tephra identification and tephro-chronology. Off-campus groups, such as consulting companies, government agencies, and other academic institutions, may also use this service, which is supported by an extensive searchable database of western U.S. tephras.