Publikationen

Cl-36 exposure dating with a 3-MV tandem

Autor(en)
Peter Steier, Oliver Forstner, Robin Golser, Walter Kutschera, Martin Martschini, Silke Merchel, Tobias Orlowski, Alfred Priller, Christof Vockenhuber, Anton Wallner
Abstrakt

Cl-36 AMS measurements at natural isotopic concentrations have yet been performed only at tandem accelerators with 5 MV terminal voltage or beyond. We have developed a method to detect Cl-36 at natural terrestrial isotopic concentrations with a 3-MV system, operated above specifications at 3.5 MV.

 

An effective separation was obtained with an optimized split-anode ionization chamber design (adopted from the ETH/PSI Zurich AMS group), providing a suppression factor of up to 30,000 for the interfering isobar S-36. Despite the good separation, a relatively high sulfur output from the ion source (S-36(-)/Cl-35(-) approximate to 4 x 10(-10) for samples prepared from chemically pure reagents), and a possibly cross contamination resulted in a background corresponding to Cl-36/Cl approximate to 3 x 10(-14). The method was applied to samples containing between 10(5) and 10(6) atoms Cl-36/g rock from sites in Italy and Iran, which were already investigated by other laboratories for surface exposure dating. The Cl-36/Cl ratios in the range from 2 x 10(-13) to 5 x 10(-12) show a generally good agreement with the previous results.

 

These first measurements demonstrate that also 3-MV tandems, constituting the majority of dedicated AMS facilities, are capable of Cl-36 exposure dating, which is presently the domain of larger facilities.

Organisation(en)
Isotopenphysik
Externe Organisation(en)
Helmholtz-Zentrum Dresden-Rossendorf, CEREGE - Centre Européen de Recherche et d'Enseignement des Géosciences de l'Environnement
Journal
Nuclear Instruments & Methods in Physics Research. Section B. Beam Interactions with Materials and Atoms
Band
268
Seiten
744-747
Anzahl der Seiten
4
ISSN
0168-583X
DOI
https://doi.org/10.1016/j.nimb.2009.10.020
Publikationsdatum
2010
Peer-reviewed
Ja
ÖFOS 2012
1030 Physik, Astronomie
Link zum Portal
https://ucris.univie.ac.at/portal/de/publications/cl36-exposure-dating-with-a-3mv-tandem(bdd90459-137c-4c2c-86a2-b185381931a6).html