DETERMINATION OF 18 SIDEROPHILE ELEMENTS INCLUDING ALL PLATINUM GROUP ELEMENTS IN CHONDRITIC METALS AND IRON METEORITES BY INSTRUMENTAL NEUTRON ACTIVATION

摘要

An instrumental neutron activation method is developed to analyze chondritic metals and iron meteorites. By changing irradiation and decay times, and selecting suitable gamma-ray and X-ray photopeaks, not only all platinum group elements (Ru, Rh, Pd, Os, Ir, Pt) but also other siderophilic elements (Fe, Co, Ni, Cu, Ga, Ge, As, Mo, Sb, W, Re, Au) can be nondestructively determined in the meteoritic metal samples, To obtain analytical data as accurate as possible, interfering reactions and neutron nux gradients during irradiation are considered, Siderophile elemental abundances measured for the Odessa iron meteorite are highly consistent with the literature values, Rh abundances for bulk H, L, LL, EH, and EL chondrites, which had been scarcely reported in the literature, are derived from Rh/Ni abundance ratios in the metal separates of the corresponding chondritic groups.