Accelerator mass spectrometry of 26 Al at 6 MV using AlO − ions and a gas-filled magnet

Miltenberger, Klaus-Ulrich; Müller, Arnold; Suter, M.; Synal, Hans-Arno; Vockenhuber, Christof

doi:10.1016/j.nimb.2017.02.013

Cited by 9 publications

(4 citation statements)

References 12 publications

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“…development of ion detection methods to suppress 10 B interference at low energies (Grajcar et al, 2004(Grajcar et al, , 2007Müller et al, 2008Müller et al, , 2010; iv. development of the gas-filled magnet method to enable magnesium suppression for 26 Al measurements using AlO − ions (Paul et al, 1989;Arazi et al, 2004;Fifield et al, 2007;Miltenberger et al, 2017).…”

Section: Al At Anstomentioning

confidence: 99%

“…In contrast, the molecular AlO − beam is typically on the order of 10-20 times higher than Al − , but ion detection of 26 Al requires suppression of the interfering 26 Mg ions that are injected into the accelerator as 26 MgO − . Whilst the separation of 26 Al and 26 Mg can be done using the gas-filled magnet technique (Paul et al, 1989;Arazi et al, 2004;Fifield et al, 2007;Miltenberger et al, 2017), the latter requires large accelerators ( 6 MV) and one may need to compromise the efficiency of ion transport and detection, which would reduce the advantage of the higher ionisation yield. An alternative emerging technique involves the use of lasers to suppress the 26 MgO − ions after the ion source (Martschini et al, 2019;Lachner et al, 2019Lachner et al, , 2021.…”

Section: Ion Ar He Acceleratormentioning

confidence: 99%

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Technical note: Accelerator mass spectrometry of 10Be and 26Al at low nuclide concentrations

Wilcken

Codilean²,

Fülöp³

et al. 2022

Geochronology

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Abstract. Accelerator mass spectrometry (AMS) is currently the standard technique to measure cosmogenic 10Be and 26Al concentrations, but the challenge with measuring low nuclide concentrations is to combine high AMS measurement efficiency with low backgrounds. The current standard measurement setup at ANSTO uses the 3+ charge state with Ar stripper gas at 6 MV for Be and 4 MV for Al, achieving ion transmission through the accelerator for 10Be3+ and 26Al3+ of around 35 % and 40 %, respectively. Traditionally, 26Al measurement uncertainties are larger than those for 10Be. Here, however, we show that 26Al can be measured to similar precision as 10Be even for samples with 26Al / 27Al ratios in the range of 10−15, provided that measurement times are sufficiently long. For example, we can achieve uncertainties of 5 % for 26Al / 27Al ratios around 1×10-14, typical for samples of late Holocene age or samples with long burial histories. We also provide empirical functions between the isotope ratio and achievable measurement precision, which allow predictive capabilities for future projects and serve as a benchmark for inter-laboratory comparisons. For the smallest signals, not only is understanding the source of 10Be or 26Al background events required to select the most appropriate blank correction method but also the impact of the data reduction algorithms on the obtained nuclide concentration becomes pronounced. Here we discuss approaches to background correction and recommend quality assurance practices that guide the most appropriate background correction method. Our sensitivity analysis demonstrates a 30 % difference between different background correction methods for samples with 26Al / 27Al ratios below 10−14. Finally, we show that when the measured signal is small and the number of rare isotope counts is also low, differing 26Al or 10Be concentrations may be obtained from the same data if alternate data reduction algorithms are used. Differences in the resulting isotope concentration can be 50 % or more if only very few (≲ 10) counts were recorded or about 30 % if single measurement is shorter than 10 min. Our study presents a comprehensive method for analysis of cosmogenic 10Be and 26Al samples down to isotope concentrations of a few thousand atoms per gram of sample, which opens the door to new and more varied applications of cosmogenic nuclide analysis.

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Section: Al At Anstomentioning

confidence: 99%

Section: Ion Ar He Acceleratormentioning

confidence: 99%

Technical note: Accelerator mass spectrometry of 10Be and 26Al at low nuclide concentrations

Wilcken

Codilean²,

Fülöp³

et al. 2022

Geochronology

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show abstract

“…In contrast, the molecular AlO − beam is typically in the order of 10 -20 times higher than Al − but ion detection of 26 Al requires suppression of the interfering 26 Mg ions that are injected to the accelerator as 26 MgO − . Whilst the separation of 26 Al and 26 Mg can be done using the gas-filled magnet technique (Paul et al, 1989;Arazi et al, 2004;Fifield et al, 2007;Miltenberger et al, 2017), the latter requires large accelerators ( 6 MV) and one may need to compromise the efficiency of ion transport and detection, which would reduce the advantage of the higher ionisation yield. An alternative emerging technique involves the use of lasers to suppress the 26 MgO − ions after the ion source (Martschini et al, 2019;Lachner et al, 2019Lachner et al, , 2021.…”

Section: Measurement Of 26 Almentioning

confidence: 99%

“…(iv) development of the gas-filled magnet method to enable magnesium suppression for 26 Al measurements using AlO − ions (Paul et al, 1989;Arazi et al, 2004;Fifield et al, 2007;Miltenberger et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Technical note: Accelerator mass spectrometry of 10Be and 26Al at low nuclide concentrations

Wilcken

Codilean

Fülöp³

et al. 2021

Preprint

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Abstract. Accelerator Mass Spectrometry (AMS) is currently the standard technique to measure cosmogenic 10Be and 26Al concentrations, but the challenge with measuring low nuclide concentrations is to combine high AMS measurement efficiency with low backgrounds. The current standard measurement setup at ANSTO uses the 3+ charge state with Ar stripper gas at 6 MV for Be and 4 MV for Al, achieving ion transmission through the accelerator for 10Be3+ and 26Al3+ of around 35 % and 40 %, respectively. Traditionally, 26Al measurement uncertainties are larger than those for 10Be. Here, however, we show that 26Al can be measured to similar precision as 10Be even for samples with 26Al / 27Al ratios in the range of 10−15, provided that measurement times are sufficiently long. For example, we can achieve uncertainties of 5 % for 26Al / 27Al ratios around 1 × 10−14, typical for samples of late-Holocene age or samples with long burial histories. We also provide empirical functions between the isotope ratio and achievable measurement precision, which allow predictive capabilities for future projects and serve as a benchmark for inter-laboratory comparisons. For the smallest signals, not only is understanding the source of 10Be or 26Al background events required to select the most appropriate blank correction method but also the impact of the data reduction algorithms on the obtained nuclide concentration becomes pronounced. Here we discuss approaches to background correction and recommend quality assurance practices that guide the most appropriate background correction method. Our sensitivity analysis demonstrates a 30 % difference between different background correction methods for samples with 26Al / 27Al ratios below 10−14. Finally, we show that when the measured signal is small and the number of rare isotope counts is also low, differing 26Al or 10Be concentrations may be obtained from the same data if alternate data reduction algorithms are used. Differences in the resulting isotope concentration can be 50 % or more if only very few ( 10) counts were recorded or about 30 % if single measurement is shorter than 10 min. Our study presents a comprehensive method for analysis of cosmogenic 10Be and 26Al samples down to isotope concentrations of few thousand atoms per gram of sample, which opens the door to new and more varied applications of cosmogenic nuclide analysis.

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Analysis of environmental radionuclides

Ješkovský

Kaizer

Kontuľ

et al. 2019

Handbook of Radioactivity Analysis: Volume 2

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Accelerator mass spectrometry of 26 Al at 6 MV using AlO − ions and a gas-filled magnet

Cited by 9 publications

References 12 publications

Technical note: Accelerator mass spectrometry of <sup>10</sup>Be and <sup>26</sup>Al at low nuclide concentrations

Technical note: Accelerator mass spectrometry of <sup>10</sup>Be and <sup>26</sup>Al at low nuclide concentrations

Technical note: Accelerator mass spectrometry of <sup>10</sup>Be and<sup> 26</sup>Al at low nuclide concentrations

Analysis of environmental radionuclides

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Accelerator mass spectrometry of 26 Al at 6 MV using AlO − ions and a gas-filled magnet

Cited by 9 publications

References 12 publications

Technical note: Accelerator mass spectrometry of &lt;sup&gt;10&lt;/sup&gt;Be and &lt;sup&gt;26&lt;/sup&gt;Al at low nuclide concentrations

Technical note: Accelerator mass spectrometry of &lt;sup&gt;10&lt;/sup&gt;Be and &lt;sup&gt;26&lt;/sup&gt;Al at low nuclide concentrations

Technical note: Accelerator mass spectrometry of &lt;sup&gt;10&lt;/sup&gt;Be and&lt;sup&gt; 26&lt;/sup&gt;Al at low nuclide concentrations

Analysis of environmental radionuclides

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Technical note: Accelerator mass spectrometry of <sup>10</sup>Be and <sup>26</sup>Al at low nuclide concentrations

Technical note: Accelerator mass spectrometry of <sup>10</sup>Be and <sup>26</sup>Al at low nuclide concentrations

Technical note: Accelerator mass spectrometry of <sup>10</sup>Be and<sup> 26</sup>Al at low nuclide concentrations