CORRECTIONS FOR CONTAMINATION BACKGROUND IN AMS C-14 MEASUREMENTS

Measurements of C-14/C-13 ratios were made on samples of Oxalic Acid a nd C-14 ''dead'' materials spanning the mass range from 10 mu g to sim ilar to 1 mg. These measurements have allowed the determination of bot h the amount, and the C-14 content, of the contaminant carbon introduc ed during sample processing in our laboratory. These data were used to correct measured C-14/C-13 ratios obtained from ANU Sucrose and ''sim ilar to one-half-life old'' test samples for the influence of the cont aminant, The test samples spanned the 10 mu g to similar to 1 mg mass range and the corrections were made using three different formulae, Th e results obtained from these calculations allow the accuracy of these background correction formulae to be evaluated.