San Francisco State University Electron Microscopy Facility

Image: Hensill Hall and Microscopy pictures

Ultra 55

Carl Zeiss Ultra 55 field emission scanning electron microscope (FE-SEM)

Ultra 55


Scanning electron microscopy is critical for the analysis of specimens studied throughout the biological and physical sciences, particularly nanoscale materials and structures. The Electron Microscopy Facility (EMF) at SF State includes a Zeiss Ultra 55 field emission scanning electron microscope which is optimized for low-voltage, high-resolution surface imaging of structures.

The Ultra 55 FE-SEM is equipped with multiple detectors to obtain the maximum information about a specimen:

1. Standard Everhart-Thornley secondary electron detector (SE2) for collection of mixed secondary and backscattered electron images with strong topography.

2. Annular on-axis secondary electron detector (In-Lens SE) for high-resolution imaging collecting only secondary electrons.

3. Angle selective Backscatter electron detector (AsB®) for Z-contrast and crystallographic imaging.

4. Annular on-axis Energy selective Backscatter electron detector (EsB®) for high sensitivity, low energy, Z-contrast imaging using backscattered electrons only.

5. STEM detector for imaging electron-transparent specimens on 3mm TEM grids. The STEM detector is equipped with six bright- and dark-field imaging modes for optimal image contrast.

6. Cathodoluminescence detector (Gatan Mini CL) for imaging light-emitting specimens over the wavelngth range 20nm to 8050nm.

7. The X-MAX 80 Energy Dispersive X-ray Spectrometer (EDS)  from Oxford instruments for chemical analysis of elements from B to U.  The large area silicon drift detector (SDD) enables short spectral acquisition times and fast elemental mapping.

8.  Electron Backscatter Diffraction (EBSD) detector from Oxford Instruments for the identification and quantification of specimen phase, orientation, and lattice mismatch.  Forward scatter diodes, attached above and below the EBSD screen, provide Z-contrast and surface-sensitive BSE imaging, respectively.

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