Prof Christopher Ramsey: Publications

An Ion Source for the HVEE ¹⁴C Isotope Ratio Mass Spectrometer for Biomedical Applications

Radiocarbon Cambridge University Press (CUP) 40:1 (1997) 283-288

Authors:

Dirk JW Mous, Wim Fokker, Rein Van Den Broek, Ron Koopmans, Christopher Bronk Ramsey, REM Hedges

Abstract:

During the past two decades, accelerator mass spectrometry (AMS) has allowed major developments in many areas of geosciences and archaeology. In the near future, AMS should realize a similar potential in the field of biomedical research, leading ultimately to clinical applications. For such applications, the required instrument differs significantly from that presently used in the field of 14C dating. Whereas the needed accuracy and sensitivity is more than an order of magnitude less demanding than that for present state-of-the-art 14C instrumentation, the widespread acceptance of 14C AMS in biomedical research will require AMS spectrometers that are small, simple to operate and capable of handling CO2 samples. In order to satisfy these demands, HVEE has developed a compact 14C AMS spectrometer dedicated to biomedical research. The instrument consists of a compact accelerator with a footprint of 2.25 × 1.25 m and an ion source that features direct CO2 acceptance and optimal user friendliness. Having previously described the layout and design of the accelerator, we here discuss progress on the accelerator and present the design and first results of the CO2 ion source.

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Imaging of radiocarbon-labelled tracer molecules in neural tissue using accelerator mass spectroscopy (vol 383, pg 823, 1996)

NATURE 390:6657 (1997) 315-315

Authors:

REM Hedges, ZX Jiang, CB Ramsey, A Cowey, JDB Roberts, P Somogyi

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Methodological Issues in the ¹⁴C Dating of Rock Paintings

Radiocarbon Cambridge University Press (CUP) 40:1 (1997) 35-44

Authors:

REM Hedges, Christopher Bronk Ramsey, GJ Van Klinken, PB Pettitt, Christina Nielsen-Marsh, Alberto Etchegoyen, JO Fernandez Niello, MT Boschin, AM Llamazares

Abstract:

Chemical and isotopic analyses have been made of pigment samples from two separate rock art sites in Argentina. The purpose of the study has been to establish the feasibility of extracting carbonaceous material from the samples which will permit reliable radiocarbon dates for the time of painting. The two sites, Catamarca and Rio Negro, present quite different problems. Most of the paper is concerned with Catamarca, and here we have shown that the paint pigments contain very little or no organic binder; but they do contain calcium oxalate derived from local cacti, and calcium carbonate derived probably from local plant ash. We describe a method to purify carbon extracted from the calcium oxalate, and present the dates obtained on both components. We show that, though rare, natural deposits containing both calcium oxalate and calcite do occur, but that they are very distinct in both 13C and 14C compositions; and we argue that they are very unlikely to contaminate the pigments to such an extent that the 14C dates are altered. For the Rio Negro site we show that the ground for the paint pigments contains carbon derived from fires burnt inside the cave, and discuss how analytical methods provide information to develop a strategy for extracting material, from both ground and pigment, for more reliable dating.

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Probability and Dating

Radiocarbon Cambridge University Press (CUP) 40:1 (1997) 461-474

Abstract:

Statistical analysis is becoming much more widely used in conjunction with radiocarbon dating. In this paper I discuss the impact of Bayesian analysis (using computer programs such as OxCal) on archaeological research. In addition to simple analysis, the method has implications for the planning of dating projects and the assessment of the reliability of dates in their context.A new formalism for describing chronological models is introduced here: the Chronological Query Language (CQL), an extension of the model definitions found in the program OxCal.New methods of Bayesian analysis can be used to overcome some of the inherent biases in the uncertainty estimates of scientific dating methods. Most of these methods, including 14C, uranium series and thermoluminescence (TL), tend to favor some calendar dates over others. 14C calibration overcomes the problem where this is possible, but a Bayesian approach can be used more generally.

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Imaging of radiocarbon-labelled tracer molecules in neural tissue using accelerator mass spectrometry

Nature Springer Nature 383:6603 (1996) 823-826

Authors:

REM Hedges, ZX Jiang, C Bronk Ramsey, A Cowey, JDB Roberts, P Somogyi

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Prof Christopher Ramsey

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An Ion Source for the HVEE ¹⁴C Isotope Ratio Mass Spectrometer for Biomedical Applications

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Imaging of radiocarbon-labelled tracer molecules in neural tissue using accelerator mass spectroscopy (vol 383, pg 823, 1996)

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Methodological Issues in the ¹⁴C Dating of Rock Paintings

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Probability and Dating

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Imaging of radiocarbon-labelled tracer molecules in neural tissue using accelerator mass spectrometry

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Prof Christopher Ramsey

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An Ion Source for the HVEE 14C Isotope Ratio Mass Spectrometer for Biomedical Applications

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Imaging of radiocarbon-labelled tracer molecules in neural tissue using accelerator mass spectroscopy (vol 383, pg 823, 1996)

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Methodological Issues in the 14C Dating of Rock Paintings

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Abstract:

Probability and Dating

Abstract:

Imaging of radiocarbon-labelled tracer molecules in neural tissue using accelerator mass spectrometry

Authors:

An Ion Source for the HVEE ¹⁴C Isotope Ratio Mass Spectrometer for Biomedical Applications

Methodological Issues in the ¹⁴C Dating of Rock Paintings