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U.S. Geological Survey Fact Sheet 2012–3067

In cooperation with the Stanford University School of Earth Sciences

The Stanford-U.S. Geological Survey SHRIMP Ion Microprobe—A Tool for Micro-Scale Chemical and Isotopic Analysis

By Charles R. Bacon, Marty Grove, Jorge A. Vazquez, and Matthew A. Coble

Thumbnail of and link to report PDF (950 kB)Summary

Answers to many questions in Earth science require chemical analysis of minute volumes of minerals, volcanic glass, or biological materials. Secondary Ion Mass Spectrometry (SIMS) is an extremely sensitive analytical method in which a 5–30 micrometer diameter “primary” beam of charged particles (ions) is focused on a region of a solid specimen to sputter secondary ions from 1–5 nanograms of the sample under high vacuum. The elemental abundances and isotopic ratios of these secondary ions are determined with a mass spectrometer. These results can be used for geochronology to determine the age of a region within a crystal thousands to billions of years old or to precisely measure trace abundances of chemical elements at concentrations as low as parts per billion. A partnership of the U.S. Geological Survey and the Stanford University School of Earth Sciences operates a large SIMS instrument, the Sensitive High-Resolution Ion Microprobe with Reverse Geometry (SHRIMP–RG) on the Stanford campus.

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    USGS Information Services, Box 25286,
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Contact Information
Stanford–USGS Micro Analysis Center
Green Earth Sciences Building
367 Panama Mall, room 89A
Stanford, CA 94305-2220

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Suggested citation:

Bacon, C.R., Grove, M., Vazquez, J.A., and Coble, M.A., 2012, The Stanford-U.S. Geological Survey SHRIMP ion microprobe—a tool for micro-scale chemical and isotopic analysis: U.S. Geological Survey Fact Sheet 2012–3067, 4 p. (Available at

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