THE CARBONATE C-14 BACKGROUND AND ITS COMPONENTS AT THE LEIBNIZ AMS FACILITY

After routine accelerator mass spectrometry (AMS) radiocarbon dating h ad been established at the Leibniz-Labor with the completion of system s for CO2 production, graphitization, and target making, a systematic investigation was conducted to find the sources of C-14 concentrations observed in background materials. We quantified the contributions of the AMS-system, the reduction, CO2 production from carbonate, carbonat e contamination, and combustion. Carbonate contamination appears to be the dominating factor. Improvements in the pretreatment of foraminife r carbonate have led to the elimination of most of this contamination.