Scanning Electron Microscopes

The SEM laboratory is part of the Department of Geosciences at the University of Fribourg and located within the GeoImage and Analytics Core Facility. The laboratory is aimed at conducting research by providing scientific advice and access to the use of the laboratory infrastructure. 

The TESCAN TIMA scanning electron microscope is suitable for high-resolution imaging, element analyses by energy dispersive spectroscopy (EDS) of up to a full thin section or epoxy block, and particle-by-particle analyses. The SEM is equipped with a Schottky Field Emission electron source as well as various detectors and can analyze samples of various sizes. 

Analytical specifications of the SEM: 

• The SEM is equipped with a high-resolution analytical Field emission column with a Schottky electron source. The acceleration voltage can be varied from 50 eV to 30 keV and the beam current from 1 pA to 100 nA. The image resolution is 1.0 nm at 30 keV and the largest field of view is 4 mm. 
  
  
• The 5-axis motorized compucentric goniometer stage has a 130 (X) x 130 (Y) x 100 (Z) mm travel range. 

• Detectors include: secondary electron (SE), backscattered electron (BSE), low energy (<1 keV) backscattered electron (LE-BSE), cathodoluminescence (CL for luminescing materials in the (visible) 350–650 nm wavelength range), two retractable energy dispersive (EDS) detectors (Mn K alpha best resolution 129 eV, 30 mm2). 

• A low-vacuum mode (MultiVac up to 700 Pa by water vapor or N2 atmosphere) can be used for analyzing non-conductive and sensitive samples that should not be carbon coated (e.g., for analyses of organic matter, plastic particles). 

• The TESCAN Essence EDS software allows acquisition of EDS spectra from regions or points, line scans and element mapping over defined areas, including mineral identification and analyses of qualitative element abundances. 

• The integrated TIMA software permits whole thin section or epoxy block element mapping at resolutions as low as 0.5 mm, including element quantification and phase analyses, particle-by-particle analyses, bright phase mapping, quantification of particle abundances and grain size distribution.