SIMS is an acronym that stands for Secondary Ion Mass Spectrometer.
A SIMS is a combination of an Ion Microprobe with a Mass Spectrometer , allowing in situ sampling of material using a primary beam of accellerated ions (commonly oxygen or cesium), and the analysis of the sputtered material, which consists of charged ions of all mass species in both the primary beam and target material, using a mass spectrometer.
A special type of SIMS is the SHRIMP (Sensitive High Resolution Ion Microprobe), which, because of its large source slit, double focusing arrangement and size, achieves both superior sensitivity (masses of small abundance can be accurately determined) and high mass resolution (closely spaced mass peaks, or interference peaks, can be resolved)
--Bdewaele 10:31, 2 Jan 2005 (UTC)