Microprobe

A microprobe is an analytical instrument that allows in situ measurement of chemical abundances, through the use of a primary beam of accellerated electrons (electron microprobe) or ions (ion microprobe) and a detector system.

Electron microprobes are part and parcel of many Scanning Electron Microscopes (SEM ), optimised to produce a very stable electron beam that remains focused on one spot rather than scanning over a sample as the more common SEMs. An electron microprobe is able to determine the chemical composition of target material because the high energy electrons of the primary beam penetrate the target material and interact with the atoms in the material to generate small amounts of X-rays. Because every element has a known, characteristic set of X-rays (X-ray spectrum ), the identification of characteristic wavelengths allows qualitative analysis, while counting of X-rays corresponding to a specific set of peaks of an element, and comparison with standard materials, allows quantitative analysis. Electron Microprobe analysis are either done with WDS detectors (Wave Length Dispersive Spectrometry ) or with an EDS detector (Energy Dispersive Spectrometry )

Ion microprobes are instruments in their own right, and are often only used for chemical analyses, rather than for imaging.--Bdewaele 10:48, 2 Jan 2005 (UTC)