Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf
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Cosmogenic nuclides: Endless opportunities?Merchel, S.
The Forschungszentrum Dresden-Rossendorf expands its measurement capability by another highly-sensitive analytical method: accelerator mass spectrometry (AMS). The method will be mainly used for the determination of long-lived cosmogenic radionuclides. In contrast to ordinary decay counting, AMS scientists do not wait for the disintegration of a radioactive nucleus. In fact, they determine directly the not-yet-decayed radionuclides by mass spectrometry, which is much more efficient.
There is a main advantage of using a high-energy accelerator for mass spectrometry: The background and interfering signals, resulting from molecular ions and ions with similar masses e.g. isobars, are nearly completely eliminated. Thus, AMS generally provides much lower detection limits in comparison to conventional mass spectrometry. Our AMS system offers excellent measurement capabilities also for external users. In contrary to common low-energy AMS facilities in Europe, which have mainly specialized in radiocarbon analyses (14C), the FZD-AMS is the first modern-type facility in the EU that will run at a terminal voltage of 6 MV.
The benefits from using AMS for radiation protection, nuclear safety, nuclear waste, radioecology, phytology, nutrition, toxicology, and pharmacology research are obvious and manifold: Smaller sample sizes, easier and faster sample preparation, higher sample throughput and the redundancy for radiochemistry laboratories will largely reduce costs. Lower detection limits will widen applications to shorter and longer time-scales and to sample types that could never been investigated before.
In environmental and geosciences, the determination of long-lived cosmogenic radionuclides like 10Be, 26Al, and 36Cl became more and more important within the last twenty years. Using these nuclides dating of suddenly occurring mass movements, e.g. volcanic eruptions, rock avalanches, tsunamis, meteor impacts, earth quakes and glacier movements, is possible. The so-called in-situ produced cosmogenic nuclides have proved to be valuable tools for quantifying Earth's surface processes also on longer time-scales and wider areas, e.g for the determination of basin-wide erosion rates. Additionally, glacier movements and data from ice cores containing atmospherically produced nuclides give hints for the reconstruction of historic climate changes and providing information for the validation of climate model predicting future changes.
Within the project CRONUS-EU the European-wide interdisciplinary network has focussed on basic data problems, that could strongly influence the quality of applications in geosciences. We have e.g. performed round-robin exercises and lowest-level measurements at different AMS facilities and cross-calibrations, searched for explanations for discrepancies in published production rates, explored new nuclide-matrix possibilities, and investigated in detail other sources of errors like scaling and nuclear reaction models.
Keywords: accelerator mass spectrometry, cosmogenic nuclides, AMS
Invited lecture (Conferences)
GeoKolloquium - Geowissenschaftliches Kolloquium der Fakultät für Geowissenschaften, Geotechnik & Bergbau, TU Bergakademie Freiberg, 08.04.2009, TU Bergakademie Freiberg, Germany
Contribution to external collection
in: http://www.rsg.tu-freiberg.de/twiki/bin/view/Main/GeoKolloquium, Freiberg: TU Bergakademie Freiberg, 2009