Hf-W灭绝核素体系是制约行星、早期星子金属-硅酸盐相分异过程的一个重要工具。岩浆成因铁陨石是来自古老小行星核部的残片，Hf-W定年是为铁陨石母体定年最有效的手段。然而受宇宙射线辐射影响，铁陨石中的W同位素会发生热中子捕捉反应, 不能反映其原始组成。本项目拟在建立和完善高精度的W同位素分析方法的基础上，测量不同族铁陨石的W和Os同位素组成，探索Os同位素作为铁陨石中热中子密度指示剂的适用性和影响条件，完善校正模型，进而利用该模型校正宇宙射线辐射对W同位素的影响，比较不同族铁陨石校正辐射影响后的W同位素组成上的变化，从而制约太阳系早期各类铁陨石母体的凝聚和分异历史。

The 182Hf-182W short-lived radionuclide system is of significant importance in studying the metal-silicate differentiation of terrestrial planets and planetesimals in the early Solar System. Magmatic iron meteorites are the remnants of the cores of old planetesimals. Hf-W system is especially tailored for dating metal-silicate differentiation of iron meteorite parent bodies. However, the abundance of 182W in iron meteorites can be easily affected by their long exposure to galactic cosmic rays (GCR) through neutron capture reactions. The purpose of this project is to: (1) develop an high-precision method for tungsten isotopic determination; (2) determine the W and Os isotopic composition of iron meteorites from different groups; (3) evaluate the robustness of osmium isotopes as a tracer for correcting the GCR effects on W isotopes; (4) compare the difference in 182W abundance between different iron meteorite groups after GCR effect correction, and to further constrain the accretion and differentiation history of iron meteorite parent bodies.