Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

DREAMS, the DREsden AMS-facility, is performing routine accelerator mass spectrometry for the isotopes ¹⁰Be, ²⁶Al, ³⁶Cl, ⁴¹Ca and ¹²⁹I. Sample ratios of ¹⁰Be/⁹Be as low as 8 x 10^-15 (background-corrected) have been measured and an exposure age of about 330 years of a boulder of 3000 t in Nepal could be determined [1]. We could demonstrate that a by-product of ice core drilling, so-called drilling chips, are also suitable for ¹⁰Be analysis of ice cores, instead of using valuable ice core samples. A set of several in-house ²⁶Al and ⁴¹Ca standards has been made traceable to primary standards by cross-calibration [2]. Numerous ²⁶Al and ⁴¹Ca concentrations of meteorites could be determined, but for marine sediments there is still a need for a low-level (10^-13) ²⁶Al standard. ICP-MS measurements have shown that the steel pins used to fix the CaF₂ sample material in the cathodes have high K-concentrations of (44.6 ± 2.2) μg/g. By replacing the steel pins with copper pins the ⁴¹K background during ⁴¹Ca measurements could be lowered by a factor of three.
Ref. : [1] W. Schwanghart et al., Science (2015), DOI:10.1126/ science.
aac9865. [2] G. Rugel et al., Nucl. Instr. Meth.B (2015), in review.