Co-precipitated silver-metal oxide aggregates for accelerator mass spectrometry of 10Be and 26Al

We have developed a chemical co-precipitation method for producing conductive Ag-BeO and Ag-Al2O3 aggregates for Be-10 and Al-26 analyses. Co-precipitation offers a rapid alternative to grinding and mixing Be and Al oxides with Ag or Cu powder, and ensures that Al and Be oxide grains produced by baking are uniformly dispersed in the conductive Ag matrix. Co-precipitated aggregates are bulkier than pure oxides and require little or no grinding, hence samples containing significantly less than 250 mug of Be-9 can be manipulated and analysed, increasing the efficiency of Be-10 measurements. Binding BeO with Ag reduces the chance of hazardous BeO dust escaping during sample preparation. Although ion currents from co-precipitated Ag-BeO cathodes are lower than from mixed Nb-BeO, savings in preparation time may offset longer analysis times. (C) 2004 Elsevier B.V. All rights reserved.