Towards micro-samples radiocarbon dating at INFN-LABEC, Florence

Fedi, M.; Barone, Serena; Barile, F.; Liccioli, Lucia; Manetti, M.; Schiavulli, L.

doi:10.1016/j.nimb.2019.12.020

Cited by 10 publications

(5 citation statements)

References 12 publications

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“…14 C AMS measurements were performed at INFN-LABEC, Florence, using the dedicated beam line of the 3MV tandem accelerator (Fedi et al 2007). Traditional-sized large samples (about 700 micrograms graphite) were prepared using the multi-purpose combustiongraphitization line (Fedi et al 2013), while smaller samples of the order of 50 micrograms graphite were prepared using the newly assembled so-called Lilliput reactors, specifically designed and assembled to graphitize very small samples, down to 50 micrograms (Fedi et al 2020). 14 C/ 12 C isotopic ratios as measured by AMS were normalized using the ratio measured in a set of NIST OxAcII samples after correction for background (by measuring blank samples) and for isotopic fractionation (by measuring 13 C/ 12 C along the AMS beam line itself).…”

Section: Methodsmentioning

confidence: 99%

Direct Radiocarbon Dating of Charcoal-Based Ink in Papyri: A Feasibility Study

et al. 2020

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When dating documents by radiocarbon (14C), what we typically measure is the concentration of the support (e.g. paper, parchment, or papyrus). This can however lead to a possible misinterpretation of results because the support may be older than the writing itself. To minimize such a possible ambiguity, the ideal approach would be direct dating of the ink or color (if organic). Here we propose a feasibility study to date carbon-based black inks when deposited on papyrus, one of the most widespread writing supports used in the past. We prepared test samples, using a commercial papyrus and a homemade black ink, obtained combining modern charcoal fragments and Arabic gum. Even though the ink binder might have represented the best candidate to be dated, we verified by FTIR that the molecular composition of its soluble fraction is very similar to papyrus extractives, thus identifying the residual charcoals recovered after extraction as the most suitable material for the measurement. Enough charcoal material was extracted from the test samples and processed using our new setup optimized for microgram-size samples. The overall experimental procedure was found to be reproducible, and measured 14C concentrations were coherent with the data obtained from larger samples and raw materials.

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Section: Methodsmentioning

confidence: 99%

Direct Radiocarbon Dating of Charcoal-Based Ink in Papyri: A Feasibility Study

et al. 2020

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“…The selected materials were chemically digested (about 5 mg each) collecting different fractions every 20 seconds (when possible). The CO 2 collected from each of the fractions was reduced to graphite optimizing the partial pressure of gas to fit the graphitization reactors optimized for micrograms-sized samples (Lilliput experiment, Fedi et al 2020); the pressure was reduced for every sample by ∼66%. The prepared samples were measured at the INFN-LABEC AMS facility in Firenze (Fedi et al 2007).…”

Section: Mortar Radiocarbon Datingmentioning

confidence: 99%

“…The bulk material was wet sieved to select the most suitable fractions (finest and softer grains). For graphitization, the selected fractions, after the chemical digestion process, were reduced to a partial pressure equivalent to ∼50 μg of carbon and converted to graphite using the so-called Lilliput line (Fedi et al 2020). The possibility of using this graphitization set-up for small samples represents an advantage in case of low amount of calcite minerals in the collected samples, or scarcity of mortar material.…”

Section: Introductionmentioning

confidence: 99%

Characterization and Selection of Mortar Samples for Radiocarbon Dating in the Framework of the Modis2 Intercomparison: Two Compared Procedures

Artioli,

Barone,

Fedi

et al. 2024

Radiocarbon

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For several decades, many efforts have been dedicated to enhancing the accuracy of mortar radiocarbon dating and evaluating the reliability of the results concerning the typology of the examined specimens. Several assumptions that are fundamental for the application of the method may be in many cases not fulfilled, such as (a) complete primary limestone dissociation during calcination, (b) efficient separation of geogenic carbon contained in calcareous aggregates, (c) short carbonation time, and (d) absence of secondary calcite. Many laboratories all over the world have proposed different methods to select suitable fractions of mortar. The first intercomparison attempt, involving eight international laboratories, was organized in 2016 aiming at comparing and statistically treating the results obtained on the same materials by different laboratories with their own characterization and pre-treatment methods (Hajdas et al. 2017; Hayen et al. 2017). Following this first step, a new intercomparison experiment was proposed and set up in 2018 during the Mortar Dating International Meeting (Bordeaux, FR). A new set of three mortar samples was chosen, taking care of the selection of standardized materials (homogeneity, known mineralogical composition, absence of exogenous inclusions, known expected age). This work describes the results of two research teams involved in the intercomparison. The samples were characterized, selected, and dated depending on each laboratory strategy. The results stress the importance of the characterization of the raw material is to better understand the mineralogical and petrographical composition of the samples. Such information can support the choice of the most appropriate strategy for the extraction of CO2 and then for data interpretation.

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“…Since the mass of the straw fragments after the pretreatment was clearly smaller than the initial collected mass, in the order of about a few hundreds of micrograms, graphitization was carried out using our so-called Lilliput graphitization line, specifically designed for microgram-sized samples (Fedi et al 2020a(Fedi et al , 2020b. In particular, this line is optimized for samples sizes corresponding to about 50 micrograms of carbon.…”

Section: Plasters Characterization and Collection Of Samples For Radi...mentioning

confidence: 99%

Radiocarbon Dating of Straw Fragments in the Plasters of St. Philip Church in Archaeological Site Hierapolis of Phrygia (Denizli, Turkey)

et al. 2023

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Absolute dating of plasters and mortars clearly represents a key information to study important structures and buildings that may have undergone a difficult story starting from their construction. This is for instance the case of the architectures in the archaeological site of Hierapolis (Denizli, Turkey). However, when discussing about the possibility to apply radiocarbon (14C) dating, in this site the presence of different sources of contaminants, due to the geological and geochemical conditions and to the used raw materials, prevents the binder dating. As an alternative, we thus decided to focus on the small fragments of straw that had been used as additives in the mortar/plaster matrices. The fragments were identified, selected and dated using a 14C experimental set-up specifically optimized for microgram-sized samples. The obtained results were satisfying, even though the measured 14C ages also pointed out some possible criticalities in dating such small samples collected from a carbonaceous matrix.

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Towards micro-samples radiocarbon dating at INFN-LABEC, Florence

Cited by 10 publications

References 12 publications

Direct Radiocarbon Dating of Charcoal-Based Ink in Papyri: A Feasibility Study

Direct Radiocarbon Dating of Charcoal-Based Ink in Papyri: A Feasibility Study

Characterization and Selection of Mortar Samples for Radiocarbon Dating in the Framework of the Modis2 Intercomparison: Two Compared Procedures

Radiocarbon Dating of Straw Fragments in the Plasters of St. Philip Church in Archaeological Site Hierapolis of Phrygia (Denizli, Turkey)

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