A new graphite preparation line for AMS 14C dating in the Zagreb Radiocarbon Laboratory

The new line for preparation of graphite samples for 14C dating by AMS has been constructed in the Zagreb Radiocarbon Laboratory. The performance of the rig and sample preparation procedure has been validated by preparing graphites from various reference materials of known 14C activity. The yield of the graphitization was good and the measured fraction of modern carbon (Fm) values have not significantly deviated from the expected ones. Detailed analysis of measured Fm values indicates a slight bias to more positive values and should be carefully investigated.