Secondary ion mass spectrometry

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This article describes a type of spectrometry; for the video games, see List of Sim games.

Secondary ion mass spectrometry (SIMS) is the process of ion formation that involves bombarding the surface to be tested with a beam of primary ions. The surface then emits material, some of which is in the form of secondary ions. These secondary ions are measured with a mass spectrometer to determine the quantitative elemental or isotopic composition of the surface. SIMS is the most sensitive surface analysis technique, but it is more difficult to obtain quantitative results compared to other techniques.

Contents 1 History 2 Detection limits 3 Static and dynamic modes 4 Applications 5 See also 6 External links 7 References

[edit] History

The first observation of ion-induced neutrals and positive ions was made by J. J. Thomson in 1910.^{[citation needed]} Fundamental experiments for SIMS were undertaken by Herzog and Viehböck, in 1949, at the University of Vienna, Austria.^{[citation needed]} Two SIMS instruments were developed independently in the early 1960s. An American project, led by Liebel and Herzog was sponsoreed by the NASA at GCA Corp, Massachusetts, with the target of analyzing moon rocks.^{[citation needed]} A French project was initiated at the University of Orsay by Raimond Castaing in the framework of the PhD thesis of Georges Slodzian.^{[citation needed]} Both instruments were later manufactured by GCA Corp and Cameca, which is located in the Paris area and is still involved in SIMS instrumention.^{[citation needed]} These first instruments were based onto a magnetic double focusing sector mass spectrometer. In the earliest 1970s, SIMS instruments were developed with quadrupole mass analyzers, firstly by Alfred Benninghoven at the University of Munster, Germany and K.Wittmack in the Munich area.^{[citation needed]} In the early 1980s SIMS Instruments based on 'time-of-flight mass spectrometers were developed at the University of Münster by Benninghoven, Niehus and Steffens and also by Charles Evans & Associates (Redwood City, CA, USA).^{[citation needed]}

[edit] Detection limits

Detection limits for most trace elements are between 10¹² and 10¹⁶ atoms per cubic centimeter.^{[citation needed]} Achievable detection limits are highly dependent on the type of instrumentation used, the primary ion beam used and the analytical area, amongst other factors. Depending on the current (pulsed or continuous) and dimensions of the primary ion beam (often Cs⁺, O^- or Ga⁺) then the analysis may be extremely surface sensitive or could go very deep into the sample, eroding a crater in realtime.

[edit] Static and dynamic modes

In the field of Surface Analysis, it is usual to distinguish Static SIMS and Dynamic SIMS. Static SIMS is the process involved in surface atomic monolayer analysis, usually with a pulsed ion beam and a time of flight mass spectrometer, while Dynamic SIMS is the process involved in bulk analysis, closely related to the sputtering process, using a DC primary ion beam and a magnetic sector or quadrupole mass spectrometer.^{[citation needed]}

[edit] Applications

The COSIMA instrument on board the Rosetta was the first instrument to determine the composition of cometary dust with secondary ion mass spectrometry.^[1]

[edit] See also

• SHRIMP

[edit] External links

• Excellent tutorial pages for SIMS theory and instrumentation, where the book Secondary Ion Mass Spectrometry: Basic Concepts, Instrumental Aspects, Applications, and Trends, by A. Benninghoven, F. G. Rüdenauer, and H. W. Werner, Wiley, New York, 1987 (1227 pages), is cited as "the best SIMS reference". For a presentation describing Time of Flight SIMS see TOF SIMS presentation.
• SIMS workshop, site includes a literature database [1]

[edit] References

1. ^ C. Engrand, J. Kissel, F. R. Krueger, P. Martin, J. Silén, L. Thirkell, R. Thomas, K. Varmuza. "Chemometric evaluation of time-of-flight secondary ion mass spectrometry data of minerals in the frame of future in situ analyses of cometary material by COSIMA onboard ROSETTA". Rapid Communications in Mass Spectrometry 20: 1361-1368. DOI:10.1002/rcm.2448.