An evaluation of the minor isotope ratio uncertainties based on traceable standards from new brunswick laboratory

Certified reference material (CRM) standards are used for calibration of mass spectrometer instruments, for measurement control, and for validating analytical methods used by safeguards laboratories. We evaluated the minor isotopic data on plutonium CRMs 136, 137, 138, and 126-A to estimate the contributing factors to the uncertainty budgets of these ratios. Data evaluated were obtained using the total evaporation methodology, which is considered the gold standard for major ratio measurements. For the minor isotope ratios, the per turret correction yielded overall uncertainties that are a factor of 2 to 3 smaller than the correction based on an assumed correction factor using the specified abundance sensitivity. LA-UR-22–22,150.