The following post is a Secondary Ion Mass Spectroscopy Spectroscopy (SIMS) Tutorial ( PowerPoint in PDF format) complements of Eric Krosche. Although a destructive technique, SIMS is also the most sensitive surface analysis technique with detection limits as low as parts per billion.
Additional SIMS tutorials:
Secondary Ion Mass Spectroscopy Wiki
Eagle Analytical Labs SIMS Theory
Note that the SIMS workshop links list of SIMS systems providers is missing a few companies such as Hiden and Extrel