Carbon background and ionization yield of an AMS system during 14C measurements of microgram-size graphite samples

Liebl, Jakob; Steier, Peter; Golser, Robin; Kutschera, W.; Mair, Klaus; Priller, Alfred; Vonderhaid, Iris; Wild, Eva Maria

doi:10.1016/j.nimb.2012.06.015

Cited by 9 publications

(10 citation statements)

References 30 publications

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“…To investigate AMS performance on graphite targets produced with the ultra-small reactors, a large suite of primary and secondary 14 C standards spanning a mass range of 6-100 µg C were prepared and measured on a single wheel, CFAMS041513. We do not observe the same rapid collapse in 12 C + beam current reported by Santos et al (2007) and Liebl et al (2013) with ultra-microscale graphite targets produced on <4 mg of reduced iron catalyst ( Figure 6). From our 6 and 25 µg C targets, produced with 2.5 mg of catalyst, we were able to obtain 6-10 individual measurements, each lasting 3 min or 30,000 14 C counts, whichever came first.…”

Section: Beam Current Yield From Ultra-small Graphite Targetssupporting

confidence: 46%

Ultra-Small Graphitization Reactors for Ultra-Microscale ¹⁴C Analysis at the National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) Facility

et al. 2015

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ABSTRACT. In response to the increasing demand for 14 C analysis of samples containing less than 25 µg C, ultra-small graphitization reactors with an internal volume of ~0.8 mL were developed at NOSAMS. For samples containing 6 to 25 µg C, these reactors convert CO 2 to graphitic carbon in approximately 30 min. Although we continue to refine reaction conditions to improve yield, the reactors produce graphite targets that are successfully measured by AMS. Graphite targets produced with the ultra-small reactors are measured by using the Cs sputter source on the CFAMS instrument at NOSAMS where beam current was proportional to sample mass. We investigated the contribution of blank carbon from the ultra-small reactors and estimate it to be 0.3 ± 0.1 µg C with an Fm value of 0.43 ± 0.3. We also describe equations for blank correction and propagation of error associated with this correction. With a few exceptions for samples in the range of 6 to 7 µg C, we show that corrected Fm values agree with expected Fm values within uncertainty for samples containing 6-100 µg C.

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Section: Beam Current Yield From Ultra-small Graphite Targetssupporting

confidence: 46%

Ultra-Small Graphitization Reactors for Ultra-Microscale ¹⁴C Analysis at the National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) Facility

et al. 2015

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“…Methods for samples in solution were initially developed for processing DNA in aqueous solution (Bergmann et al 2012) and the most extensive studies were carried out for this material (Liebl et al 2010, 2013). The smallest sample, measured with an overall precision of 2.4%, was a 4.7 µg C DNA sample (2.2 µg C extracted as CO 2 ).…”

Section: Sample Preparation Of µG Samplesmentioning

confidence: 99%

Preparation Methods of μg Carbon Samples for¹⁴C MeasuremenTS

et al. 2016

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Systematic investigations and experience from several application projects on small carbon samples over a number of years have resulted in measuring the radiocarbon content of 10 μg C samples with an overall precision of typically 1%. A substantial reduction of the carbon contamination during graphitization was achieved, resulting in 31±30 ng modern and <100 ng 14C-free carbon. Thus, graphitization is no longer the limiting factor because earlier sample preparation steps usually introduce much larger contamination. The method has been extended to a variety of materials and applied to various projects. Realistic conditions for procedure development can only be achieved in the context of applications on true samples; methods developed are the lyophilization of samples in solution, combustion, ultraviolet oxidation, or carbonate hydrolysis with phosphoric acid, which allows to prepare samples for a wide range of applications. Insights gained from systematic investigations and from real applications are presented.

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“…[3]), this may be called the second revolution of radiocarbon dating (the first was atom counting versus decay counting). Small AMS facilities such as the mini radiocarbon dating system MICADAS in Zurich [4] occupy a floor space of less than 10 m 2 , which is comparable to the space requirement for a standard mass spectrometer.…”

Section: -P2mentioning

confidence: 99%

“…Here only a few microgram of DNA were available for the 14 C AMS measurements, demanding a particular careful sample preparation in every step from the human tissue to the final carbon sample [3]. Figure 6 shows that very little if any new neurons were formed in the human olfactory bulb after birth [21], in stark contrast to rodents where 50% turnover in adulthood has been observed.…”

Section: Dating Human Dna With the 14 C Bomb Peakmentioning

confidence: 99%

Accelerator mass spectrometry – from DNA to astrophysics

Kutschera

2013

EPJ Web of Conferences

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Abstract.A brief review of accelerator mass spectrometry (AMS) is presented. The present work touches on a few technical aspects and recent developments of AMS, and describes two specific applications of AMS, the dating of human DNA with the 14 C bomb peak and the search for superheavy elements in nature. Since two extended general reviews on technical developments in AMS [1] and applications of AMS [2] will appear in 2013, frequent reference to these reviews is made.

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Carbon background and ionization yield of an AMS system during 14C measurements of microgram-size graphite samples

Cited by 9 publications

References 30 publications

Ultra-Small Graphitization Reactors for Ultra-Microscale ¹⁴C Analysis at the National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) Facility

Ultra-Small Graphitization Reactors for Ultra-Microscale ¹⁴C Analysis at the National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) Facility

Preparation Methods of μg Carbon Samples for¹⁴C MeasuremenTS

Accelerator mass spectrometry – from DNA to astrophysics

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Carbon background and ionization yield of an AMS system during 14C measurements of microgram-size graphite samples

Cited by 9 publications

References 30 publications

Ultra-Small Graphitization Reactors for Ultra-Microscale 14C Analysis at the National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) Facility

Ultra-Small Graphitization Reactors for Ultra-Microscale 14C Analysis at the National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) Facility

Preparation Methods of μg Carbon Samples for14C MeasuremenTS

Accelerator mass spectrometry – from DNA to astrophysics

Contact Info

Product

Resources

About

Ultra-Small Graphitization Reactors for Ultra-Microscale ¹⁴C Analysis at the National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) Facility

Ultra-Small Graphitization Reactors for Ultra-Microscale ¹⁴C Analysis at the National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) Facility

Preparation Methods of μg Carbon Samples for¹⁴C MeasuremenTS