TY  - GEN
AV  - public
ID  - heidok24767
UR  - https://archiv.ub.uni-heidelberg.de/volltextserver/24767/
Y1  - 2018///
TI  - A new target preparation facility for high precision AMS measurements and strategies for efficient 14CO2 sampling
N2  - The aim of this thesis was to allow for the processing of large-scale atmospheric 14CO2 samples into graphite targets for high-precision analysis on an accelerator mass spectrometer (AMS) and to further develop the sampling itself, which takes place throughout Europe within the Integrated Carbon Observation System (ICOS) network. For the ?rst part, a largely automated Extraction and Graphitisation Line (EGL) was developed at the ICOS Central Radiocarbon Laboratory(CRL); the construction at the institute workshop was guided and process behaviour and target quality was characterised. Process fractionation in ?13C from the whole-air sample ?ask to the graphite target cannot be distinguished from zero with (0.04 ± 0.09)?. The deviation from the absolute canonical ?14C scale was determined to (0.7 ± 0.5)?. It was shown that the reproducibility of ?14C results from processed air samples is at ±1.9? or below for the ?nal graphitisation parameters. Compatibility tests provided a deviation of the results of samples processed with EGL and analysed by the AMS at the Curt-Engelhorn-Centre Archaeometry (CEZ) from the results of the CRL Low-Level Counting (LLC) laboratory of (2.2 ± 0.9)?. The reason for the deviation is currently unknown. For the further development of 14CO2 sampling, a new trajectory-triggered strategy was simulated in an atmospheric forward modelling system. It was shown that weak fossil CO2 signals from emission hotspots at four German ICOS stations can be ampli?ed by a factor of up to 7, while the signal background is estimated with parallely taken samples.
A1  - Lux, Johannes Thomas
ER  -