The Central Radiocarbon Laboratory
The analytical technique of the Heidelberg 14C-laboratory was originally based on high precision proportional gas counting. The ICOS-CRL will continue using this conventional counting technique to allow for a smooth transition to state-of-the-art Accelerator Mass Spectrometry (AMS) radiocarbon analysis and provide a solid link to the historic data sets. ICOS-CRL operates up to 19 proportional gas counters, which are located in an underground laboratory, specially shielded against cosmic radiation. The analytical capacity of these counters is 500 unknown samples per year at precision of 2 ‰ or better. The majority of the atmospheric air samples from the ICOS RI atmospheric station network will however be analyzed by AMS. For both analytical techniques we developed optimized CO2 extraction and processing methods and built the respective semi-automated processing lines in house. The AMS 14C analyses are currently performed at the CEZA laboratory in Mannheim. One important aim is to maintain a long-term compatibility of both analytical techniques of better than 1 ‰.
Apart from the analytical challenge of making accurate and precise atmospheric 14CO2 measurements, the ICOS-CRL operates an urban atmospheric measurement station in order to test and implement new methods for atmospheric fossil fuel CO2 (ffCCO2) quantification. New surrogate tracers or sampling strategies are tested here before they are implemented in the ICOS RI atmospheric station network.
Tasks of the CRL
- analyses of up to 500 samples via gas proportional counting
- extraction of CO2 from flask samples with subsequent graphitization for AMS analysis for up to 1500 samples per year
- comprehensive quality management from an internal to an international level
ICOS network support
- serve the atmospheric ICOS sampling network with CO2-free NaOH solution for high volume CO2 absorption
- build integrated high-volume 14CO2 samplers for the conventional gas counting method
- develop new 14CO2 sampling equipment
Fossil fuel CO2 estimation
- operation of an atmospheric pilot station measuring all major greenhouse gases, stable isotopes in CO2 as well as 222Rn progeny
- assessment of new sampling strategies or surrogate tracers