scanning electron microscope

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun An electron microscope that forms a three-dimensional image on a cathode-ray tube by moving a beam of focused electrons across an object and reading both the electrons scattered by the object and the secondary electrons produced by it.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun An electron microscope whose image is made up of a matrix of points from scanning the surface of a sample.