Berlin 2014 – wissenschaftliches Programm
MS 11.6: Vortrag
Freitag, 21. März 2014, 12:00–12:15, DO24 1.205
Analysis of Primordial Nuclides in High Purity Copper with Accelerator Mass Spectrometry — Nicolai Famulok, •Karin Hain, Thomas Faestermann, Leticia Fimiani, José Gomez Guzman, Peter Ludwig, Gunther Korschinek, and Stefan Schönert — Technische Universität München, Physik Department, Garching
The sensitivity of experiments in rare event physics like neutrino or direct dark matter detection crucially depends on the background level. Therefore, all material surrounding the detectors requires low contamination of radionuclides to not create additional background. A significant contribution originates from the primordial actinides thorium and uranium and the progenies of their decay chains.
At the Maier Leibnitz Laboratorium in Munich the applicability of ultra-sensitive Accelerator Mass Spectrometry (AMS) for the direct detection of thorium and uranium impurities in a copper matrix was tested for the first time. For this special purpose, Th and U were extracted from the ion source as a copper compound. Two different samples of copper and one sample of a copper alloy were investigated. The lowest concentrations achieved with these first AMS measurements were (1.4±0.6)·10−11 g/g for thorium and (7±4)·10−14 g/g for uranium which correspond to (56±16) µBq/kg and (0.9±0.5) µBq/kg, respectively.
The particular requirements on the AMS technique and the developed measurement procedure will be presented, followed by a discussion of the results of the first measurements.