Attempts to understand potential deficiencies in chemical procedures for AMS


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Thomas.Opel [ at ] awi.de

Abstract

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 aging 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-aged 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.



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ISI/Scopus peer-reviewed
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Published
Eprint ID
49832
DOI 10.1016/j.nimb.2019.05.005

Cite as
Merchel, S. , Beutner, S. , Opel, T. , Rugel, G. , Scharf, A. , Tiessen, C. , Weiß, S. and Wetterich, S. (2019): Attempts to understand potential deficiencies in chemical procedures for AMS , Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms . doi: 10.1016/j.nimb.2019.05.005


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