Direct Detection of Radiocarbon Using Accelerator Techniques and Its Application to Age Measurements

Radiocarbon measurements by the direct detection of 14 C atoms with the Tandetron accelerator mass spectrometer were begun in the autumn of 1983 at Nagoya University. The 14 C dating of geological and archeological samples is routinely performed with a precision of ±1% (±83 years) using a carbon-silver target containing only 2–5 mg of carbon in measurements lasting 5 hours. The accuracy of a single 14 C measurement was estimated by a reproducibility test to be ±1.34%. Radiocarbon ages measured with the Tandetron spectrometer for ten natural samples agreed well with those obtained by radioactivity measurements. The 14 C background of the spectrometer limits the measurable age to less than 60000 y BP. The limit will be extended to about 82000 y BP if the 14 C background is eliminated.