The Central Radiocarbon Laboratory (CRL) is one of the Central Analytical Laboratories of ICOS Research Infrastructure. It is affiliated to the Institute of Environmental Physics of Heidelberg University.
The ICOS-CRL builds upon the former Heidelberg Radiocarbon (14C) laboratory, which was operated for more than 50 years by the Heidelberg Academy of Sciences and the Institute of Environmental Physics of Heidelberg University. The Heidelberg Radiocarbon laboratory gained international recognition in many scientific fields exploiting radiocarbon, such as groundwater dating, oceanography, tree ring analysis as well as atmospheric and carbon cycle research. The main task of the ICOS CRL is high precision analysis of CO2 samples from the ICOS atmospheric station network.
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.