Uncertainty Components Evaluated in the Determination of the Massic Activity CA (in units of MBq · g−1) for Rhenium-186 Perrhenate Solution Used in Experiment 1

LS measurement repeatabilityStandard deviation in CA for 10 repeated measurements on a single LS cocktail; average for 8 independent LS cocktails.0.13
LS cocktail variabilityStandard deviation in CA for 8 independently prepared LS cocktails; average for 8 independent LS cocktails.0.0091
LS composition variabilityStandard deviation for determination of CA for LS cocktails containing 0.9% aqueous fraction as H2O (4 cocktails) and 0.9% aqueous fraction as 9% saline (4 cocktails).0.15
186Re half-lifeStandard uncertainty in half-life (0.08%) over the measurement decay interval.0.0023
186Re EC branching ratioStandard uncertainty in EC branching (1.3%).0.08
186Re β-branching ratioStandard uncertainty in β-branching (0.12%).0.10
Gravimetric determinationsStandard uncertainty in mass determinations for a single LS counting source.0.05
186Re dilution factorStandard uncertainty in gravimetric determination of dilution from 186Re master solution0.07
3H-standard decay correctionEstimated standard uncertainty of 0.46% in the decay of the 3H standard over 18.5 a to 19 a.0.01
3H-standard calibrationStandard uncertainty of 0.18% from NIST calibration.0.01
3H-standard gravimetric dilutionEstimated standard uncertainty (0.06%) for gravimetrically-determined dilution factor.0.01
Gravimetric determination of 3H LS samplesEstimated standard uncertainty of 0.05% in the mass determination of any single 3H LS cocktail.0.01
Spectrometer dependenceStandard deviation in CA for 8 independently-prepared LS cocktails counted in 2 spectrometers.0.56
Combined (uc = Σui)0.61
Expanded (Uc = uc · k; k = 2)1.22