Khandelwal Deeksha, Kumar Pankaj, Kumar P V, Singh Atul K, Rawat Mahadev, Dawar Anit, Sharma R, Ojha S, Gargari S, Mukherjee P K, Chopra S, Pandey A C
National Geochronology Facility, Inter-University Accelerator Centre (IUAC), New Delhi, India.
J Mass Spectrom. 2025 Jan;60(1):e5103. doi: 10.1002/jms.5103.
A large geometry high resolution secondary ion mass spectrometer (HR-SIMS) has been established as a part of the National Geochronology Facility (NGF) at Inter-University Accelerator Centre (IUAC), New Delhi. The performance of the instrument related to high spatial resolution, high mass resolving power (MRP), sensitivity of the instrument to measure low abundant isotopes, and sensitivity of the instrument for Pb signal under different conditions are optimized and presented in this paper. We report the precision of the order of ~ 0.2‰ for oxygen isotopes measurement in 91500 reference material zircon and measured δO value of 10.08‰ ± 0.18‰ (2SD), which is in agreement with the recommended values. For U-Pb age measurement in zircon, Plešovice and FCT reference materials are measured as unknown and their Pb/U ages agree with the reported values within the uncertainties. A long-term evaluation of Pb/UO and Pb/U isotopic measurement ratio is also presented.
一台大型几何结构高分辨率二次离子质谱仪（HR-SIMS）已作为位于新德里的大学间加速器中心（IUAC）国家地质年代学设施（NGF）的一部分建立起来。本文对该仪器在高空间分辨率、高质量分辨率（MRP）、测量低丰度同位素的仪器灵敏度以及不同条件下仪器对Pb信号的灵敏度等方面的性能进行了优化并呈现。我们报告了在91500参考物质锆石中氧同位素测量精度约为0.2‰，测量的δO值为10.08‰±0.18‰（2SD），这与推荐值一致。对于锆石中的U-Pb年龄测量，将普莱绍维采（Plešovice）和FCT参考物质作为未知样品进行测量，其Pb/U年龄在不确定度范围内与报道值一致。还给出了对Pb/UO和Pb/U同位素测量比值的长期评估。
