Microanalyses by electrons: The ultimate alchemist (GC-09)
A tool developed since the 1950's, the electron microprobe analyzer, allows geologists to determine chemical compositions of particles only a few micrometers (.001 millimeter) in size. In this instrument a bean of electrons at high voltage is focused on the specimen by electromagnetic lenses. The electron bean causes the sample to emit X-rays with characteristics that depend on the chemistry of the sample. Each chemical element emits X-rays of a unique kind. By comparing the kinds and amounts of radiation with those of well-known standard materials, the elements and their amounts in the sample can be calculated.
Our Hoosier State Beneath Us: Geochemistry/Geophysics