© University of Liverpool, Department of Earth, Ocean & Ecological Sciences 2013
Earth, Ocean & Ecological Sciences
Scanning Electron Microscope (SEM) The SEM is a type of electron microscope that images a sample by scanning it with a very narrow beam of electrons. This type of microscope uses a focused beam of high-energy electrons which generates a range of signals when it hits a solid object and interacts with its surface. These signals provide information about the texture and chemical composition of the sample as well as details of the crystalline structure and orientation of the materials in the sample. Areas ranging from approximately 1 cm to 5 microns in width can be imaged by the SEM with magnification ranging from 20X to 30,000X. The SEM may produce very high-resolution images of a sample, showing details less than 1 nm in size and, because SEM images have a large depth of field, these images indicate the three-dimensional appearance of the sample’s surface. Photographs here show the Philips XL 30 SEM with a four element KE backscatter detector and a link ISIS x-ray diffraction detector. The other advantages of using the scanning electron microscope are that it also allows us to: analyse selected point locations on the sample, show spatial variations in chemical compositions and produce elemental maps for the sample. . .
SEM images The SEM images (a) and (b) were taken on a thin section of the Jurassic Osmington Mills Ironstone Formation, Dorset. The third photograph is taken on a sample of the materials found in one of the research tanks at the University of Liverpool’s Botanical Gardens at Ness, South Wirral. Here is a link to a website showing the images taken by Alex Cairns during his work experience placement in the Department of Earth and Ocean Sciences. If you would like more information about how you to arrange a work experience placement in Earth and Ocean Sciences, please contact Chris Hunt in the School of Environmental Sciences by sending an email to:
Materials are marked as suitable for: Undergraduates  ‘A’ level students  GCSE students