High sensitivity determination of iridium contents in ultra-basic rocks by INAA with coincidence gamma-ray detection

Mitsuru Ebihara*, Naoki Shirai, Jin Kuwayama, Yosuke Toh

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Very low contents (in the range of 10−9 g/g) of Ir in mantle-derived rock samples (komatiites) were non-destructively determined by INAA coupled with coincidence gamma-ray spectrometry using 16 Ge detectors. Aliquots of the same samples were analyzed by NiS fire-assay ICP-MS for Ir and other platinum group elements. Because the INAA procedure used in this study is non-destructive and is almost free from spectral interference in gamma-ray spectrometry, the INAA values of Ir contents obtained in this study can be highly reliable. Iridium values obtained by ICP-MS were consistent with the INAA values, implying that the ICP-MS values of Ir obtained in this study are equally reliable. Under the present experimental conditions, detection limits were estimated to be 1 pg/g, which corresponds to 0.1 pg for a sample mass of 0.1 g. These levels can be even lowered by an order of magnitude, if necessary, which cannot be achieved by ICP-MS carried out in this study.

Original languageEnglish
JournalNuclear Engineering and Technology
DOIs
Publication statusAccepted/In press - 2021

Keywords

  • Coincidence counting
  • Inductively coupled plasma mass spectrometry (ICP-MS)
  • Instrumental neutron activation analysis (INAA)
  • Iridium
  • Multiple Ge detector System
  • Ultra-basic rocks

ASJC Scopus subject areas

  • Nuclear Energy and Engineering

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