超高空間分解能型二次イオン質量分析器NanoSIMS によるイメージング法：隕石と海底下微生物への応用

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On November 4, 2011, the Cameca NanoSIMS 50L ion microprobe was delivered to Kochi Institute for Core Sample Research. The NanoSIMS is the state-of-the-art instrument for microanalysis by secondary ion mass spectrometry, and offers an extremely fine focusing of a primary ion beam. A spatial resolution of less than 50 nm is achieved using the Cs+ as a primary ion beam, whereas the O- primary ion beam can be focused in about 150-nm resolution. Up to 7 elemental and/or isotopic images can be acquired simultaneously by 7 electron multipliers with ppm-level high sensitivity. This allows us to compare the SIMS images concerning the precise distribution of different isotopes or elements. This performance for imaging with sub-μm spatial resolution is a very unique to the NanoSIMS and provides a new approach to analyze the isotope and/or elemental distributions in samples. Therefore, the JAMSTEC NanoSIMS will be a powerful tool for ion imaging and marine-biology laboratories at Kochi Institute for Core Sample Research and will be used to investigate extraterrestrial, terrestrial and biological samples, including meteorites, Earth rocks and microbial cells in deep and ancient subseafloor sediments obtained by an Integrated Ocean Drilling Program. This paper presents the current achievements for meteorites and biological samples analyzed by the NanoSIMS imaging technique with a sub-μm resolution.