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The Sensitive High Resolution Ion Microprobe (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. ==History and scientific impact== 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.〔 The first major scientific impact was the discovery of Hadean (>4000 million year old) zircon grains at Mt. Narryer in Western Australia〔 and then later at the nearby Jack Hills.〔 These results and the SHRIMP analytical method itself were initially questioned〔〔 but subsequent conventional analysis were partially confirmed.〔〔 SHRIMP-I also pioneered ion microprobe studies of titanium,〔 hafnium〔 and sulfur〔 isotopic systems. Growing interest from commercial companies and other academic research groups, notably Prof. John de Laeter of Curtin University (Perth, Western Australia), led to the project in 1989 to build a commercial version of the instrument, the SHRIMP-II, in association with ANUTECH, the Australian National University's commercial arm. Refined ion optic designs in the mid-1990s prompted development and construction of the SHRIMP-RG (Reverse Geometry) with improved mass resolution. Further advances in design have also led to multiple ion collection systems (already introduced in the market by a French company years before), negative-ion stable isotope measurements and on-going work in developing a dedicated instrument for light stable isotopes.〔 Fifteen SHRIMP instruments have now been installed around the world〔〔 and SHRIMP results have been reported in more than 2000 peer reviewed scientific papers. SHRIMP is an important tool for understanding early Earth history having analysed some of the oldest terrestrial material including the Acasta Gneiss〔〔 and further extending the age of zircons from the Jack Hills.〔 Other significant milestones include the first U/Pb ages for lunar zircon〔 and Martian apatite〔 dating. More recent uses include the determination of Ordovician sea surface temperature,〔 the timing of snowball Earth events〔 and development of stable isotope techniques.〔〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Sensitive high-resolution ion microprobe」の詳細全文を読む スポンサード リンク
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