Prof Christopher Ramsey: Publications

An Independent Chronology for British Bronze Age Metalwork: The Results of the Oxford Radiocarbon Accelerator Programme

Archaeological Journal Taylor & Francis 154:1 (1997) 55-107

Authors:

Stuart Needham, Christopher Bronk Ramsey, David Coombs, Caroline Cartwright, Paul Pettitt

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An Experiment to Refute the Likelihood of Cellulose Carboxylation

Radiocarbon Cambridge University Press (CUP) 40:1 (1997) 59-60

Authors:

REM Hedges, Christopher Bronk Ramsey, G-J Van Klinken

Abstract:

To test the hypothesis that cellulose in linen can be carboxylated at high temperatures in the presence of CO2, water and silver, we heated two aliquots of cellulose extracted from old wood in glass ampoules, adding Ag powder to one to test its potential action as a catalyst for the carboxylation reaction. AMS measurement of the heated aliquots showed no statistically significant difference in 14C content from the “uncarboxylated” cellulose. We conclude that carboxylation is not a systematic source of error in the dating of cellulose-containing materials such as the linen in the Shroud of Turin.

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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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Prof Christopher Ramsey

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An Independent Chronology for British Bronze Age Metalwork: The Results of the Oxford Radiocarbon Accelerator Programme

Authors:

An Experiment to Refute the Likelihood of Cellulose Carboxylation

Authors:

Abstract:

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

Authors:

Abstract:

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

Authors:

Methodological Issues in the ¹⁴C Dating of Rock Paintings

Authors:

Abstract:

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Prof Christopher Ramsey

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An Independent Chronology for British Bronze Age Metalwork: The Results of the Oxford Radiocarbon Accelerator Programme

Authors:

An Experiment to Refute the Likelihood of Cellulose Carboxylation

Authors:

Abstract:

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

Authors:

Abstract:

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

Authors:

Methodological Issues in the 14C Dating of Rock Paintings

Authors:

Abstract:

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

Methodological Issues in the ¹⁴C Dating of Rock Paintings