Assessing metal matrices to improve AMS precision for cosmogenic 10Be applications
Dr Ana Carracedo1, Dr Derek Fabel1, Dr Richard Shanks1
1Scottish Universities Environmental Research Centre, Glasgow, United Kingdom
The precision of cosmogenic 10Be measurements by AMS (~2% sample-to-sample reproducibility) presents a limitation when applied to Quaternary geoscience problems. To facilitate efficient sample sputtering in the ion source, BeO is dispersed in a matrix of a conductive metal. The homogeneity of this mixture and the sample matrix properties influences beam current stability and can cause measurement scatter. Optimising ion beam current stability may improve measurement accuracy. Here we investigate the effects of different metals (Nb, Fe, Mo) on current stability and measurement reproducibility. The metals were added in solid and solution form to different stages of the Be precipitation process. Mixtures of both BeO and Be(OH)2 were pressed and analyzed using the 5MV Pelletron at SUERC. In a preliminary assessment we can report that the targets containing Be(OH)2 generated high currents and that Fe matrices couple well with the ion source generating particularly stable AMS currents.
Ana did her PhD at Scottish Universities Environmental Research Centre (SUERC) developing techniques for high precision cosmogenic nuclide measurements. Following this she oversaw the establishment of the ICP-MS facility at LSC (Underground Laboratory of Canfranc). Moving back to SUERC in 2020 as a research associate improving the AMS precision for cosmogenic 10Be analysis.