The Zurich group first split each ultrasonically cleaned sample in half, with the treatment of the second set of samples being deferred until the radiocarbon measurements on the first set had been completed.
The first set of samples was further subdivided into three portions.
The Arizona group split each sample into four subsamples.
One pair of subsamples from each textile was treated with dilute HCL, dilute Na OH and again in acid, with rinsing in between (method a).
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.
Following this intercomparison, a meeting was held in Turin in September-October 1986 at which seven radiocarbon laboratories (five AMS and two small gas-counter) recommended a protocol for dating the shroud. The samples were then taken to the adjacent Sala Capitolare where they were wrapped in aluminium foil and subsequently sealed inside numbered stainless-steel containers by the Archbishop of Turin and Dr Tite.