加速器质谱14C石墨靶自动和手动制备对比研究

The Comparison of Automated and Manual Preparation of 14C Graphite Targets for Accelerator Mass Spectrometry

  • 摘要: 加速器质谱法放射性碳 (14C) 定年技术的精度与石墨靶制备品质密切相关。本研究系统评估了自动石墨化系统 (AGE3) 与真空系统 (VAC) 在石墨靶制备中的性能差异。结果表明:AGE3制备的IAEA标准样品绝对偏差为0.03%~0.17% pMC,优于VAC系统;两种系统制备的OX-Ⅱ和PHA结果具有一致性,沉积物样品变异系数 (CV) 为0.27%,地下水样品CV=0.12%~2.33%,验证了两种系统制样可靠性;AGE3日处理通量>14个,效率较VAC提升2倍以上,适用样品的高通量制备;前处理方法优化使AGE3和VAC碳载量下限突破至0.3 mg C,满足珍贵微量样品分析需求;AGE3操作便捷,石墨化程序固定,VAC灵活性高,石墨化流程可调控。两种系统均具备良好的可靠性和稳定性,可为沉积物和地下水定年、古气候重建等研究提供高效技术方案参考。

     

    Abstract: The precision of radiocarbon (14C) dating techniques depends on the quality of graphite target preparation. This study systematically evaluated the performance differences between the automated graphitization system (AGE3) and vacuum system (VAC) in graphite target preparation. The results showed that the absolute deviation of the IAEA standards prepared by the AGE3 was 0.03%-0.17% pMC, superior to the VAC system. Both systems exhibited consistency in OX-Ⅱ and PHA preparations, and the coefficient of variation (CV) of the two systems is 0.27% for sediment samples and CV=0.12%-2.33% for groundwater samples. AGE3 can process more than 14 samples per day, which is over twice the efficiency of VAC, making it suitable for high-throughput sample preparation. Optimized pretreatment methods had lowered the minimum measurable carbon mass to 0.3 mg C in both systems, fulfilling the analytical requirements for trace-level precious samples. The AGE3 system is user-friendly, featuring a fixed graphitization program. In contrast, the VAC system is highly flexible with a controllable graphitization process. Both systems produce high-quality graphite targets with excellent precision and stability, providing efficient technical solutions for research in sediment and groundwater dating, paleoclimate reconstruction and other studies.

     

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