title: A new target preparation facility for high precision AMS measurements and strategies for efficient 14CO2 sampling
creator: Lux, Johannes Thomas
subject: ddc-500
subject: 500 Natural sciences and mathematics
subject: ddc-530
subject: 530 Physics
subject: ddc-540
subject: 540 Chemistry and allied sciences
subject: ddc-550
subject: 550 Earth sciences
description: 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 first 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 δ13C from the whole-air sample flask to the graphite target cannot be distinguished from zero with (0.04 ± 0.09)‰. The deviation from the absolute canonical Δ14C scale was determined to (0.7 ± 0.5)‰. It was shown that the reproducibility of Δ14C results from processed air samples is at ±1.9‰ or below for the final 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 amplified by a factor of up to 7, while the signal background is estimated with parallely taken samples.
date: 2018
type: Dissertation
type: info:eu-repo/semantics/doctoralThesis
type: NonPeerReviewed
format: application/pdf
identifier: https://archiv.ub.uni-heidelberg.de/volltextserverhttps://archiv.ub.uni-heidelberg.de/volltextserver/24767/1/DissertationJohannesLuxFinal.pdf
identifier: DOI:10.11588/heidok.00024767
identifier: urn:nbn:de:bsz:16-heidok-247671
identifier:   Lux, Johannes Thomas  (2018) A new target preparation facility for high precision AMS measurements and strategies for efficient 14CO2 sampling.  [Dissertation]     
relation: https://archiv.ub.uni-heidelberg.de/volltextserver/24767/
rights: info:eu-repo/semantics/openAccess
rights: http://archiv.ub.uni-heidelberg.de/volltextserver/help/license_urhg.html
language: eng