Tackling challenges in AMS sample preparation

Since 2009 the DREAMS (DREsden Accelerator Mass Spectrometry) facility offers users to do their own sample preparation for AMS targets. A large number of samples from interdisciplinary research Topics such as astronomy, climate, cosmochemistry and geology could be transformed into BeO, Al₂O₃, AgCl and CaF₂ showing reasonable to excellent performance [Rugel et al., this DPG.]. However, besides our constant approach to become a little better every day, sometimes very new challenges can arise due to the low availability of the sample material, low radionuclide concentration or a possible contamination of the sample with disturbing elements and nuclides. Two examples:

Ice samples are always in our focus. As we were facing Problems with ¹⁰Be contamination in "dirty" ground ice, we measured ³⁶Cl and ^natCl by isotope dilution in permafrost ice wedge samples as heavy as 1.6 kg. The chemical yield of AgCl was only 20-35% (and is a function of total ^natCl), which might be improved by preconcentration steps.
For the determination of in-situ or atmospheric ²⁶Al in marine and terrestrial sediments [e.g. Gärtner et al., this DPG.], we had sometimes unaccountable low chemical yields, which seems to be partially due to
redissolving aluminium hydroxide in the last washings.
Thanks to A. Gärtner, P. Ludwig, D. Rodrigues and several students for providing/processing samples.