The sensitive high-resolution ion microprobe (also sensitive high mass-resolution ion microprobe or SHRIMP) is a large-diameter, double-focusing secondary ion mass spectrometer (SIMS) sector instrument produced by Australian Scientific Instruments in Canberra, Australia. Like other SIMS instruments, the SHRIMP microprobe bombards a sample under vacuum with a beam of primary ions that sputters secondary ions that are focused, filtered, and measured according to their energy and mass.
The SHRIMP is primarily used for geological and geochemical applications. It can measure the isotopic and elemental abundances in minerals at a 30 micrometre-scale and is therefore well-suited for the analysis of complex minerals, as often found in metamorphic terrains, some igneous rocks, and for relatively rapid analysis of statistical valid sets of detrital minerals from sedimentary rocks. The most common application of the instrument is in uranium-thorium-lead geochronology, although the SHRIMP can be used to measure some other isotopic and elemental abundances.
The SHRIMP originated in 1973 with a proposal by Prof. Bill Compston, trying to build an ion microprobe at the Research School of Earth Sciences of the Australian National University that exceeded the sensitivity and resolution of ion probes available at the time in order to analyse individual mineral grains. Optic designer Steve Clement based the prototype instrument (now referred to as 'SHRIMP-I') on a design by Matsuda which minimised aberrations in transmitting ions through the various sectors. The instrument was built from 1975 and 1977 with testing and redesigning from 1978. The first successful geological applications occurred in 1980.