TY - JOUR
T1 - Enhanced beam currents with co-precipitated niobium as a matrix for AMS measurements of 10Be
AU - Berggren, Ann Marie
AU - Possnert, Göran
AU - Aldahan, Ala
N1 - Funding Information:
We acknowledge the financial support of the Swedish Research Council, and Gary Wife and colleagues at the Microscopy Unit at the Evolutionary Biology Centre, Uppsala University who kindly helped with the SEM sessions. Thanks also to participants at the AMS11 meeting in Rome for useful comments and discussions, and to two reviewers for useful comments that helped to improve this work.
PY - 2010/4
Y1 - 2010/4
N2 - When dealing with small amounts of 10Be, it is challenging to achieve the good performance in the ion source that is needed to enable a reliable AMS measurement. We have co-precipitated beryllium with dissolved NbCl5, using a range of mixing ratios, to establish an optimal and practical procedure. 9Be16O- beam currents for co-precipitated samples of 9Be-Nb are often higher, but show a slower rise than for samples either co-precipitated or mixed with silver. However, while the Ag sample currents soon deteriorate, Nb sample currents stay high for an extended time, leading to higher measuring performance and better statistics. Although co-precipitated Be-Nb mixtures do not reach such high beam currents as BeO mechanically mixed with Nb powder, we prefer co-precipitation as it provides enough material for handling and an additional mixing step is avoided. We recommend use of NbCl5 as an alternative to AgNO3 on account of the much lower boron association of niobium compared to silver. No critical limit in the matrix:Be mixing ratio was observed, but we note a steady decline of maximum currents reached with increasing mixing ratio.
AB - When dealing with small amounts of 10Be, it is challenging to achieve the good performance in the ion source that is needed to enable a reliable AMS measurement. We have co-precipitated beryllium with dissolved NbCl5, using a range of mixing ratios, to establish an optimal and practical procedure. 9Be16O- beam currents for co-precipitated samples of 9Be-Nb are often higher, but show a slower rise than for samples either co-precipitated or mixed with silver. However, while the Ag sample currents soon deteriorate, Nb sample currents stay high for an extended time, leading to higher measuring performance and better statistics. Although co-precipitated Be-Nb mixtures do not reach such high beam currents as BeO mechanically mixed with Nb powder, we prefer co-precipitation as it provides enough material for handling and an additional mixing step is avoided. We recommend use of NbCl5 as an alternative to AgNO3 on account of the much lower boron association of niobium compared to silver. No critical limit in the matrix:Be mixing ratio was observed, but we note a steady decline of maximum currents reached with increasing mixing ratio.
KW - AMS
KW - Beam currents
KW - Beryllium-10
KW - Co-precipitation
KW - Niobium
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U2 - 10.1016/j.nimb.2009.10.033
DO - 10.1016/j.nimb.2009.10.033
M3 - Article
AN - SCOPUS:77949906720
SN - 0168-583X
VL - 268
SP - 795
EP - 798
JO - Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms
JF - Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms
IS - 7-8
ER -