Graphitization system of AMS-14C in Radiocarbon Dating Laboratory of the National Centre for Archaeology

To meet the growing demand for radiocarbon(14C) dating in archaeology, Quaternary geology and environmental research in China, the National Centre for Archaeology(NACA) established a radiocarbon dating laboratory in 2024. This laboratory is capable of performing the pretreatment and graphitization processes for a variety of samples, including plant remains, animal and human bones, as well as carbonates. Graphite synthesized from these samples can therefore be measured by an accelerator mass spectrometer(AMS)to determine their radiocarbon ages. To evaluate the performance of this newly established laboratory, a series of comparisons have been carried out on background standards that do not contain radiocarbon isotope, oxalic standards with known radiocarbon ages, including the modern OX Ⅱ(SRM 4990c), IAEA-C7 with ca. 50 pMC and IAEA-C8 with ca. 15 pMC, as well as archaeological samples that have been measured by the well-established radiocarbon laboratory in Peking University. These standards and archaeological samples have been graphitized in our laboratory and measured by two stably running AMS laboratories. Results show that the radiocarbon ages of background samples are mostly above 50 ka, measurements of standards and archaeological samples show consistent results with their reference values, and repetitive measurements of the same samples produce consistent results. These results prove that our laboratory can generate reliable results for archaeological and Quaternary research samples within 50 ka, meeting the requirements for radiocarbon dating in these studies.