Each subsample was treated with 1M HCL (80° C for 2h), 1M Na OH (80° C for 2 h) and again in acid, with rinsing in between.Two of the three samples were then bleached in Na OCL (2.5% at p H-3 for 30 min).
Even for the first investigation, there was a possibility of using radiocarbon dating to determine the age of the linen from which the shroud was woven.
The size of the sample then required, however, was ~500cm, which would clearly have resulted in an unacceptable amount of damage, and it was not until the development in the 1970s of small gas-counters and accelerator-mass-spectrometry techniques (AMS), requiring samples of only a few square centimetres, that radiocarbon dating of the shroud became a real possibility. The shroud was separated from the backing cloth along its bottom left-hand edge and a strip (~10 mm x 70 mm) was cut from just above the place where a sample was previously removed in 1973 for examination.
1 - Department of Geosciences, 2 - Department of Physics, University of Arizona, Tucson, Arizona 85721, USA 3 - Research Laboratory for Archaeology and History of Art, University of Oxford, Oxford, OX1 3QJ, UK 4 - Institut für Mittelenergiephysik, ETH-Hönggerberg, CH-8093 Zürich, Switzerland 5 - Lamont-Doherty Geological Observatory, Columbia University, Palisades, New York 10964, USA 6 - Research Laboratory, British Museum, London WC1B 3DG, UK Very small samples from the Shroud of Turin have been dated by accelerator mass spectrometry in laboratories at Arizona, Oxford and Zurich.
As Controls, three samples whose ages had been determined independently were also dated.
Photography of the shroud by Secondo Pia in 1898 indicated that the image resembled a photographic 'negative' and represents the first modern study.
Subsequently the shroud was made available for scientific examination, first in 19 by a committee appointed by Cardinal Michele Pellegrino .To confirm the feasibility of dating the shroud by these methods an intercomparison, involving four AMS and two small gas-counter radiocarbon laboratories and the dating of three known-age textile samples, was coordinated by the British Museum in 1983. The strip came from a single site on the main body of the shroud away from any patches or charred areas.The results of this intercomparison are reported and discussed by Burleigh . Three samples, each ~50 mg in weight, were prepared from this strip.At the same time, the British Museum was invited to help in the certification of the samples provided and in the statistical analysis of the results. The age of the shroud is obtained as AD 1260-1390, with at least 95% confidence. The three containers containing the shroud (to be referred to as sample 1) and two control samples (samples 2 and 3) were then handed to representatives of each of the three laboratories together with a sample of the third control (sample 4), which was in the form of threads.The procedures for taking the samples and treating the results were discussed by representatives of the three chosen laboratories at a meeting at the British Museum in January 1988 and their recommendations = standard deviation) errors, of the Shroud of Turin and control samples, as supplied by the three laboratories (A, Arizona; O, Oxford; Z, Zurich) (See also Table 2.) The shroud is sample 1, and the three controls are samples 2-4. The sampling of the shroud took place in the Sacristy at Turin Cathedral on the morning of 21 April 1988. All these operations, except for the wrapping of the samples in foil and their placing in containers, were fully documented by video film and photography.Testore of Department of Materials Science, Turin Polytechnic and G. If the samples had been unravelled or shredded rather than being given to the laboratories as whole pieces of cloth, then it would have been much more difficult, but not impossible, to distinguish the shroud sample from the controls.