Corrections for contamination background in AMS 14C measurements

Measurements of ratios were made on samples of Oxalic Acid and 14C “dead” materials spanning the mass range from 10 μg to ∼1 mg. These measurements have allowed the determination of both the amount, and the 14C content, of the contaminant carbon introduced during sample processing in our laboratory. These data were used to correct measured ratios obtained from ANU Sucrose and “∼ one-half-life old” test samples for the influence of the contaminant. The test samples spanned the 10 μg to ∼1 mg mass range and the corrections were made using three different formulae. The results obtained from these calculations allow the accuracy of these background correction formulae to be evaluated.