Measuring 10Be by AMS

For measurement of the isotopes 10Be, and 9Be, beryllium is chemically separated from sample material and analysed in two separate instruments.

For ferromanganese deposits and sediments

  • Samples are leached with acid to extract the Be.
  • A portion of the leachate is retained for 9Be measurement by inductively coupled plasma-optical emission spectroscopy (ICP-OES) using a customized instrument, which can measure part-per-billion 9Be in solutions containing other elements at much higher concentrations; errors are typically 2% RSD.
  • 0.25-0.50 mg of 9Be carrier is added to the remaining leachate to provide sufficient material for processing and to make a beryllium oxide target for 10Be measurement.
  • Pure beryllium is recovered via ion-exchange and hydroxide precipitation.
  • The Be(OH)2 is dissolved in H2SO4 and, with HF added to remove boron, evaporated and combusted to BeO.
  • This is then mixed with silver powder and pressed into a target holder for 10Be measurement by AMS. The reagent blank is about 106 atoms 10Be.
  • 10Be is measured via Accelerator Mass Spectrometry (AMS) at the National Isotope Centre, GNS Science. The methodology for measuring 10Be in BeO samples is similar to that for measuring radiocarbon in graphite samples.

The combination of careful pretreatment chemistry and customised transport of ion beams with the AMS system results in a high sensitivity for 10Be measurement free from serious interference by the isobar 10B, and 10Be/9Be values as low as 10-13 can be measured comfortably, the relative standard deviation (RSD) being 2-5%. Accuracy and precision of measurement below 10-13 depend on BeO sample quantity and cleanliness of the preparative chemistry.

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