The Sensitive High Resolution Ion MicroProbe (SHRIMP) uses a focused high-energy ion beam to sputter erode samples. Some of the material coming from the surface becomes ionized and this can be extracted electrostatically into a mass spectrometer. The SHRIMP mass spectrometer has high mass resolving power to separate atomic and molecular species. The mass spectrometer is large in order to maintain the sensitivity required for the analysis of trace element ions in a few nanograms of material.
SHRIMP is typically concerned with determination of ion ratios in geologic materials. Probe pits are typically 10-30 µm in diameter and a few micrometers deep. As such SHRIMP allows virtually nondestructive in-situ isotopic analysis of geologic materials. Such materials include polished grain mounts and thin sections. Samples are generally characterized with visual and electron imaging prior to analysis.
Applications include U-Pb geochronology, trace element geochemistry, stable isotope analysis, and measurement of cosmochemical effects in extraterrestrial samples. Three SHRIMP instruments are currently in use (SHRIMP I, II, RG) with a fourth under construction (SHRIMP SI). SHRIMP instruments are constructed commercially in Canberra at Australian Scientific Instruments and have been exported to a number of laboratories overseas.