Accelerator mass spectrometry in geology and archaeology

Here is a form for download, for description of samples for ¹⁴C dating:

• Sample form

In addition to the stable carbon isotopes ¹²C and ¹³C, the atmosphere contains the rare isotope ¹⁴C, with a half-life of 5730 years. This isotope is constantly replenished by cosmic radiation. All living beings take up carbon from the atmosphere in their metabolism, and because the carbon is constantly replaced they retain a constant level of ¹⁴C. When they die, the ¹⁴C decays while the stable isotopes remain constant. By measuring the ratio of remaining ¹⁴C to ¹²C the archaeological samples are dated.

As the ratio is typically in of the order of 10^-14 for archaeological samples, highly elaborate sample preparation procedures and precise measurements have to be performed to unambiguously determine the age of the sample. Our laboratory has a long standing expertise in both development and application of these procedures and performs state-of-the-art ¹⁴C-dating with several thousands of measurements annually for miscellaneous applications.

Complementary to ¹⁴C, other rare-isotope experiments are routinely performed for ¹⁰Beryllium and ¹²⁹Iodine. Similar in concept to ¹⁴C-dating, these experiments cover much longer time-spans due to longer half-life of the isotopes of interest. Precision-measurements of the isotopic ratios addresses other applications such as the climate history, the solar cycles and the water circulation on earth – at present and millions of years back in time.