Isotope Analysis on Iron Meteorites with Ion Probe Mass Spectrometer

Abstract

In order to investigate the isotopic effect of nickel which might have been brought into by the diffusion of nickel isotopes during the crystallization of an iron meteorite, the isotopic ratio 58Ni/60Ni and the nickel concentration were measured with the ion probe mass spectrometer. Krypton and argon ions were used as a primary ions, whose energy was 5 keV. The diameter and the current of the primary ion beam were 250 µm and 2×10-7 A on the surface of the sample target. Three iron meteorites, Odessa, Canyon Diablo and Hembury were analyzed. Two former samples belong to the class of coarse octahedrite, and the latter one medium octahedrite. The point-to-point analysis was carried out every 0.25 mm or 0.5 mm in the range of about 4 mm on the surface of the sample. The distribution of 58Ni/60Ni was likely to correlate to the nickel concentration in the case of Odessa and Canyon Diablo.