From carbon to actinides: A new universal 1MV accelerator mass spectrometer at ANSTO

Wilcken, Klaus M.; Hotchkis, M.A.C.; Levchenko, Vladimir; Fink, David; Hauser, T.; Kitchen, R.L.

doi:10.1016/j.nimb.2015.04.054

Cited by 25 publications

(14 citation statements)

References 15 publications

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“…Transmission data in Fig. 1 collates measurements on ANSTO's 1 MV VEGA (Wilcken et al, 2015) and 6 MV SIRIUS (Wilcken et al, 2017) accelerators using Be − , BeO − and BeO − 2 ions to be able to cover a wide energy range. 9 Be ion energy at the accelerator terminal is a function of the accelerator voltage and mass of the molecule injected.…”

Section: Transmission [ % ]mentioning

confidence: 61%

“…gases. The transmissions below 1 MeV ion energies were measured on VEGA and between 4 and 6 MeV on SIRIUS (Wilcken et al, 2015(Wilcken et al, , 2017.…”

Section: Measurement Of 26 Almentioning

confidence: 99%

“…out-weighted the losses in transmission. Equal ion optical transmission of about 40% can be achieved with 1+ charge state, but this reduces to about ∼30% by the time all the molecular interferences are sufficiently suppressed (Wilcken et al, 2015), and therefore offers no gain over the 3+ method.…”

Section: Measurement Of 26 Almentioning

confidence: 99%

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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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Section: Transmission [ % ]mentioning

confidence: 61%

“…gases. The transmissions below 1 MeV ion energies were measured on VEGA and between 4 and 6 MeV on SIRIUS (Wilcken et al, 2015(Wilcken et al, , 2017.…”

Section: Measurement Of 26 Almentioning

confidence: 99%

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

Wilcken

Codilean

Fülöp³

et al. 2021

Preprint

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“…The separated Pu was co-precipitated with iron(III) oxide-hydroxide (Fe{OH} 3 ), then dried and calcined to form an iron oxide matrix for AMS analysis. Measurement was undertaken by AMS on the VEGA accelerator at ANSTO (Wilcken et al, 2015). PuOions were injected into the accelerator which was operated at 0.6 MV.…”

Section: Plutonium-239+240 Chronostratigraphic Markersmentioning

confidence: 99%

Unlocking the Kimberley’s past: the applicability of organic spring deposits for reconstructing late Quaternary climatic and environmental change

Field¹

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There are limited high-resolution records of climatic and environmental change from the Kimberley region of northwest Australia. This has hindered the development of knowledge of climate and environmental change in Australia's monsoonal tropics, and the ability to provide context for the area's rich archaeological record and globally renowned rock art. The lack of high-resolution records from this region is primarily a result of the monsoonal climate which limits the presence of "classic" palaeoenvironmental archives such as perennial lakes and wetlands. Organic spring deposits are unconventional archives of past environmental change yet offer potential to provide outstanding records in arid and semi-arid regions such as the Kimberley. Despite this, the majority of existing research demonstrates complications with their use, in particular the application of standard radiocarbon (14 C) techniques to build robust chronologies of their development. Because of the importance of springs as critical palaeoenvironmental archives, and the pressing need for high-resolution records from northwest Australia, this thesis utilised three organic spring deposits to develop new, high-resolution records of climate and environmental change for the Kimberley. These records span the last ~14,500 years, and were underpinned by a new protocol for establishing robust chronologies from these settings which was developed via a rigorous geochronological investigation. Initial 14 C results from a core collected from Black Springs in 2005 were confusing, with convoluted ages below 94.5 cm limiting the reliability of an initial palaeoenvironmental reconstruction >9070 cal. yr BP. A new protocol for obtaining robust chronologies from organic spring deposits was therefore developed for cores collected from the three sites in 2015, utilising multiple geochronological methodologies including 14 C dating of different carbon fractions (stable polycyclic aromatic carbon (SPAC), macro-charcoal, pollen concentrate, bulk sediment and roots), 210 Pb dating, the application of 239+240 Pu, and high-spatial resolution, luminescence techniques (natural sensitivity-corrected luminescence (L n /T n)). Whilst L n /T n demonstrated that the organic spring deposits contained a relatively uncompromised stratigraphic record, 14 C dates were contaminated by roots, groundwater fluctuations, and incorporation of allochthonous "old" carbon. SPAC isolated by the hydrogen pyrolysis (HyPy) pre-treatment appeared to remove postdepositional sources of alteration, and therefore provided a viable approach for constructing chronologies in these settings. Developing more recent chronologies (i.e. the past 100 years) using 210 Pb was found to be problematic due to the behaviour of the springs as an open system with regards to uranium, suggesting this may not be possible in many spring environments. Whilst this investigation was made with respect to springs, the contamination pathways are not unique to these Publications during candidature Peer reviewed papers:

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“…Plutonium-239+240 activities in ELZ01 and BSP02 were analysed as an additional chronostratigraphic marker. These isotopes have the same anthropogenic source as caesium-137 (Wilcken et al, 2015). PuOions were injected into the accelerator which was operated at 0.6 MV.…”

Section: Plutonium-239+240 Chronostratigraphic Markersmentioning

confidence: 99%

Untangling geochronological complexity in organic spring deposits using multiple dating methods

Field

Marx

Haig

et al. 2018

Quaternary Geochronology

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Organic spring deposits have the potential to provide to outstanding records of palaeoenvironmental and climatic change, particularly in arid and semi-arid environments where establishing robust records of environmental change is challenging due to a lack of classic sedimentary records, e.g. perennial lakes and extensive wetlands. However, despite the potential of organic spring deposits a number of studies demonstrate complications in the application of standard 14 C techniques which has, in several cases, led to confusing chronologies. This implies that dynamic carbon pathways commonly occur within spring systems. Because of the importance of springs as critical palaeoenvironmental archives,

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From carbon to actinides: A new universal 1MV accelerator mass spectrometer at ANSTO

Cited by 25 publications

References 15 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

Unlocking the Kimberley’s past: the applicability of organic spring deposits for reconstructing late Quaternary climatic and environmental change

Untangling geochronological complexity in organic spring deposits using multiple dating methods

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From carbon to actinides: A new universal 1MV accelerator mass spectrometer at ANSTO

Cited by 25 publications

References 15 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

Unlocking the Kimberley’s past: the applicability of organic spring deposits for reconstructing late Quaternary climatic and environmental change

Untangling geochronological complexity in organic spring deposits using multiple dating methods

Contact Info

Product

Resources

About

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