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SHRIMPⅡe MC被广泛应用于锆石、磷灰石、碳酸钙等副矿物的氧同位素分析。本工作针对其氧同位素分析过程中的边缘效应及几何效应(X-Y效应),建立二次离子提取结构的SIMION仿真模型,探讨了XY效应、边缘效应的产生原因及影响因素,为SHRIMPⅡe MC高精度氧同位素分析提供指导。通过限制氧同位素分析点位置(样品位于靶中间直径10 mm内,靶表面粗糙度<1μm),可使锆石δ~(18)O单点内部精度优于0.15‰(1σ),外部精度优于0.5‰(95%的置信区);碳酸盐矿物δ~(18)O单点内部精度优于0.20‰(1σ),外部精度优于0.6‰(95%的置信区)。
SHRIMPⅡe MC is widely used in oxygen isotope analysis of accessory minerals such as zircon, apatite and calcium carbonate. In this work, the SIMION simulation model of secondary ion extraction structure was established according to the edge effect and geometric effect (XY effect) in the process of oxygen isotope analysis. The XY effect, the cause of edge effect and the influencing factors were discussed, which are SHRIMPⅡe MC high precision Oxygen isotope analysis provides guidance. The single point internal accuracy of δ 18 O can be better than 0.15 ‰ (1σ) by limiting the position of the oxygen isotope analysis point (the sample is located within 10 mm of the middle of the target and the target surface roughness is less than 1 μm) At 0.5 ‰ (95% confidence level), the δ 18 O single point internal accuracy of carbonate minerals is better than 0.20 ‰ (1σ) and the external precision is better than 0.6 ‰ (95% confidence level).