Analysis of ⁹⁷Tc Spike by Negative Thermal Ionization Mass Spectrometry

⁹⁷Tc spike produced by our laboratory was analyzed by negative thermal ionization mass spectrometry (NTIMS). Equal-probability model was used for correction of isotope ratio measurements. The isotope ratio of ⁹⁷Tc spike was measured with the expanded uncertainty of 1.3%(K=2). ⁹⁷Tc concentration was also determined by isotope dilution mass spectrometry (IDMS) with the expanded uncertainty of 2.12% (K=2).