Methods of radiocarbon dating
For recent material ORAU aims to get a precision of about 0.3% (typically 25-30 years).It is important to note that radiocarbon calibration usually reduces the precision of measurements considerably.
They cover most of the materials suitable for radiocarbon measurement.They are set up to measure the carbon and nitrogen compositions and stable isotope ratios.Precisions are usually better 0.1 to 0.2 per mil for δN.The radiocarbon concentration can then be used to calculate the radiocarbon age of the sample.The precision of radiocarbon dating depends on age.Once the sample has been processed to either carbon dioxide or elemental carbon (in the form of graphite).
The proportion of radiocarbon atoms in the sample is determined by AMS.
This data can also provide useful information on food webs.
In the case of human bone, this can be important for the dating itself since some aquatic diets can affect radiocarbon dates significantly.
If any uncertainties remain these are reported to the submitter in the results letter.
The research team extracted cores of beautifully preserved layers of sediment, containing organic material (such as tree leaf and twig fossils), from the bottom of the Japanese lake where they had lain undisturbed for tens of thousands of years.
All of these processes are carefully controlled at ORAU through our quality management system.