Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

A major research focus of the DREsden Accelerator Mass Spectrometry (DREAMS) facility is sample preparation: in-house and at cooperating laboratories. Besides routine applications, developments are mainly driven by the users' demands such as "new" radionuclides (e.g. short-lived ⁷Be), radionuclides from new matrices or in larger sample amounts and at lower concentrations. Within the chemical preparation of BeO for ^7,10Be, Al₂O₃ for ²⁶Al, AgCl for ³⁶Cl, and Fe₂O₃ for ⁶⁰Fe and actinide AMS targets, we investigated and improved mostly particular steps: For oxide preparation alteration for several hours and two-times rinsing of hydroxides is recommended, especially for Be(OH)₂ and Al(OH)₃, to prevent losses in the final preparation steps. Rinsing of freshly precipitated hydroxides can yield to losses as high as 31%. For Al(OH)₃ rinsing with H₂O (pH5) instead of pH8-9 is recommended for further reducing redissolving. For ⁶⁰Fe and coprecipitated actinides (the latter tested by U⁶⁺ and Er³⁺), rinsing of overnight-altered Fe(OH)₃, yield to 2.6-3.5% losses. The depletion of the isobar ⁷Li for ⁽⁷⁾BeO is easily gained by hydroxide precipitation and rinsing. The quality of BeO and Al₂O₃ AMS targets can be monitored and improved (e.g. by using larger ion exchanger columns) by using the so-called "quality factor", which is the current of the stable nuclide (⁹Be or ²⁷Al), normalised to the current of the standard of the same batch. Finally, there is a high potential for ion exchange as a pre-enrichment tool for Cl for large ice samples containing low ^natCl concentrations and low absolute amounts of ^natCl.