Axel Steinhof, Dr.
Phone: +49 (0)3641 57 - 6450
Fax: +49 (0)3641 57 - 7450
14C: Measurements of very small concentrations
The 14C analytics group assists research by providing state-of-the-art measurements of 14C concentrations in sample types of various origins, e.g. soil, sediment, wood, water, or air samples. Measuring 14C in natural samples is rather complex since the 14C/C concentration in recent samples is within the range of 10-12, or even lower in older samples. These measurements are performed by Accelerator Mass Spectrometry (AMS) with a 3-MV Tandetron ion accelerator.
AMS can be carried out with very small samples; in our lab usual sample sizes range between 0.4 and 1 mg of carbon content. In a specialized chemical preparation the carbon is extracted from the solid and gaseous samples and converted into graphite. In the ion source this graphite is first atomized and then ionized (charged negatively) by sputtering and subsequently accelerated in the accelerator by applying very high voltages of 2500 kV. With the AMS method single 14C ions can be identified, counted and afterwards the 14C concentrations are deduced.