Techniques for the determination of radiogenic strontium (⁸⁷Sr/⁸⁶Sr) and neodymium (¹⁴³Nd/¹⁴⁴Nd) isotope ratios by Thermal Ionisation Mass Spectrometry (TIMS) are presented in this study. We have developed a 5 lines acquisition routine for both elements, taking advantage of the 16 Faraday cups available on the Nu Instruments TIMS in conjunction with an efficient zoom lens system. This allows increased flexibility regarding the number of lines in a multidynamic acquisition routine whilst maintaining optimal peak alignment and peak shape for every measurement line despite the fact that the detectors are not movable. The long-term reproducibility obtained for our Sr (NBS 987) and Nd (Rennes-Ames) standard solutions gives a (⁸⁷Sr/⁸⁶Sr)_multidyn of 0.7102467 ± 0.0000043 (6.0 ppm, 2 s.d., n = 38) and a (¹⁴³Nd/¹⁴⁴Nd)_multidyn of 0.5119537 ± 0.0000022 (4.2 ppm, 2 s.d., n = 31), respectively. We also report (⁸⁷Sr/⁸⁶Sr)_multidyn and (¹⁴³Nd/¹⁴⁴Nd)_multidyn for a set of terrestrial rock standards (including 5 basalts (BCR-2, BHVO-2, BIR-1, Be-N and BR-24), one rhyolite (RGM-1) and one andesite (AGV-2)) with the same, or greater, level of precision as for the pure standards solutions. This level of precision is 2 to 3 times better than the literature data for Sr isotope ratios, and comparable to the latest high precision data reported for Nd isotope ratios. This is the first paper reporting such high precisions for radiogenic Sr and Nd data generated using a TIMS from Nu Instruments.

Significant statement

High precision Sr and Nd isotopic measurements are of key importance in the field of Earth Sciences because they are powerful tools to trace sources of materials and to date them. Here, we report the first high-precision data for ⁸⁷Sr/⁸⁶Sr and ¹⁴³Nd/¹⁴⁴Nd (external error of 5–6 ppm for Sr and 4–5 ppm for Nd) measured using a Nu Instruments TIMS. Such precisions will open new opportunities in fields such as geochemistry, geochronology, cosmochemistry, archaeology or forensics.

中文翻译：

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使用配备动态变焦镜头的热电离质谱仪进行高精度 Sr 和 Nd 同位素测量

本研究介绍了通过热电离质谱 (TIMS)测定放射性锶 ( ⁸⁷ Sr/ ⁸⁶ Sr) 和钕 ( ¹⁴³ Nd/ ^{144 Nd) 同位素比率的技术。}我们利用 Nu Instruments TIMS 上可用的 16 个法拉第杯以及高效的变焦镜头系统，为这两个元素开发了一个 5 线采集程序。这允许在多动态采集例程中增加关于线数的灵活性，同时保持每条测量线的最佳峰对齐和峰形，尽管检测器不可移动。我们的 Sr (NBS 987) 和 Nd (Rennes-Ames) 标准溶液获得的长期重现性给出了 (0.7102467 ± 0.0000043 (6.0 ppm, 2 sd, n  = 38) 的⁸⁷ Sr/ ⁸⁶ Sr) _multidyn和0.5119537 ± 0.0000022 (4.2 ppm, 2 sd, n  = 31)的 ( ¹⁴³ Nd/ ¹⁴⁴ Nd) _{multidyn 。}我们还报告了 ( ⁸⁷ Sr/ ⁸⁶ Sr) _multidyn和 ( ¹⁴³ Nd/ ¹⁴⁴ Nd) _multidyn一套陆岩标准（包括 5 种玄武岩（BCR-2、BHVO-2、BIR-1、Be-N 和 BR-24）、一种流纹岩（RGM-1）和一种安山岩（AGV-2））与纯标准溶液相同或更高的精度。这一精度水平比 Sr 同位素比率的文献数据高 2 到 3 倍，与最新报道的 Nd 同位素比率高精度数据相当。这是第一篇报告使用 Nu Instruments 的 TIMS 生成的放射性 Sr 和 Nd 数据如此高精度的论文。

重要声明

高精度 Sr 和 Nd 同位素测量在地球科学领域至关重要，因为它们是追踪材料来源和确定材料年代的强大工具。^{在这里，我们报告了使用 Nu Instruments TIMS 测量的87} Sr/ ⁸⁶ Sr 和¹⁴³ Nd/ ¹⁴⁴ Nd的第一个高精度数据（ Sr的外部误差为 5-6 ppm，Nd 的外部误差为 4-5 ppm）。这种精度将为地球化学、地质年代学、宇宙化学、考古学或法医学等领域带来新的机遇。