The mass/charge ratios of these secondary ions are measured with a mass spectrometer to determine the elemental, isotopic, or molecular composition of the surface to a depth of 1 to 2 nm.

Due to the large variation in ionization probabilities among elements sputtered from different materials, comparison against well-calibrated standards is necessary to achieve accurate quantitative results.

[1] Improved vacuum pump technology in the 1940s enabled the first prototype experiments on SIMS by Herzog and Viehböck[2] in 1949, at the University of Vienna, Austria.

One was an American project, led by Liebel and Herzog, which was sponsored by NASA at GCA Corp, Massachusetts, for analyzing Moon rocks,[4] the other at the University of Paris-Sud in Orsay by R. Castaing for the PhD thesis of G.

[5] These first instruments were based on a magnetic double focusing sector field mass spectrometer and used argon for the primary beam ions.

[8] Instruments of this type use pulsed primary ion sources and time-of-flight mass spectrometers and were developed by Benninghoven, Niehuis and Steffens at the University of Münster, Germany and also by Charles Evans & Associates.

This is needed to ensure that secondary ions do not collide with background gases on their way to the detector (i.e. the mean free path of gas molecules within the detector must be large compared to the size of the instrument), and it also limits surface contamination by adsorption of background gas particles during measurement.

The liquid metal covers a tungsten tip and emits ions under influence of an intense electric field.

For short pulsed ion beams in static SIMS, LMIGs are most often deployed for analysis; they can be combined with either an oxygen gun or a caesium gun during elemental depth profiling, or with a C60+ or gas cluster ion source during molecular depth profiling.

A microchannel plate detector is similar to an electron multiplier, with lower amplification factor but with the advantage of laterally-resolved detection.

Detection limits for most trace elements are between 1012 and 1016 atoms per cubic centimetre,[12] depending on the type of instrumentation used, the primary ion beam used and the analytical area, and other factors.

[13] The amount of surface cratering created by the process depends on the current (pulsed or continuous) and dimensions of the primary ion beam.