PhotoMetrics, Inc.
15801 Graham St.
Huntington Beach CA 92649
(714) 895-4465
Fax (714) 893-4682

e-mail: lab@photometrics.net


Scanning Electron Microscopy (SEM)


SEM provides topographical and elemental information at magnifications of 10x to 100,000x with virtually unlimited depth of field.


Joe Ant

Applications include

Principle of Operation

A finely focused electron beam scanned across the surface of the sample generates secondary electrons, backscattered electrons, and characteristic X-rays. These signals are collected by detectors to form images of the sample displayed on a cathode ray tube screen. Features seen in the SEM image may then be immediately analyzed for elemental composition using EDS or WDS.

Secondary Electron Imaging shows the topography of surface features a few nm across. Films and stains as thin as 20 nm produce adequate-contrast images. Materials are viewed at useful magnifications up to 100,000x without the need for extensive sample preparation and without damaging the sample. Even higher magnifications and resolution are routinely obtained by our Field Emission SEM.

Backscattered Electron Imaging shows the spatial distribution of elements or compounds within the top micron of the sample. Features as small as 10 nm are resolved and composition variations of as little as as 0.2% determined.

Data Output is generated in real time on the CRT monitor. Images and spectra can be printed here, recorded on CD ROM and/or emailed for insertion into your own reports.

"How an SEM works" from the Museum of Science, Boston

More information from the University of Durham with a clickable diagram of an SEM.


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