Analytical SEM (Scanning Electron Microscope)
Our state-of-the-art Zeiss Sigma HD Field Emission Gun Analytical SEM (ASEM) is the flagship of our facility.
|Make/model||Zeiss Sigma HD Field Emission Gun Analytical SEM (ASEM)|
|Details||The Schottky Thermal Field Emission Gun provides a stable beam that can be operated between 0.2 and 30 kV and 4 pA to 100 nA.|
|Facility||Electron microbeam facility|
|School||Earth and Ocean Sciences|
The ASEM is equipped with:
- an in-lens and Everhart-Thornley secondary electron detector
- a backscatter electron detector
- two Oxford Instruments 150 mm2 energy dispersive X-ray spectrometers (EDS)
- an Oxford Instruments Wave wavelength dispersive X-ray spectrometer (WDS)
- an iXRF micro-XRF source
- an Oxford Instruments Aztec electron back-scatter diffraction (EBSD) detector
- a Centaurus cathodoluminescence detector
A combination of EDS (for major and minor elements), WDS (for high-precision analysis of major and minor elements) and micro-XRF (for trace elements) means complete characterization of elements heavier than carbon can be achieved with accuracy and precision rivalling an electron microprobe.
The dual 150 mm2 EDS detectors, which can capture in excess of 1 000 000 counts per second, enable rapid, high-resolution 2D mapping of distributions of major and minor elements over relatively large areas. Since the ASEM is fully standardized, the element maps are quantitative, thus absolute element abundances can be mapped. In addition, using the micro-XRF source with an accelerating voltage of 50 kV, trace element distributions of elements heavier than Ti22 can be imaged with a resolution of 15 µm.
EBSD provides information on crystal orientations with sub-micron resolution and can be combined with EDS chemical data for textural and microstructural studies. Image referencing software allows easy navigation around the sample using images from a flatbed scanner or digital camera.
Dr Duncan Muir
- +44 (0)29 2087 5059