Radioactive dating used for dating the turin shroud
This is done using radiation detectors similar in principle to the Geiger counter.But in the case of the Shroud of Turin, this conventional testing technique would have required the use of relatively large amounts of material, the size of a handkerchief for each laboratory, more than Vatican authorities were willing to allow to be cut from the shroud.The other two isotopes in comparison are more common than carbon-14 in the atmosphere but increase with the burning of fossil fuels making them less reliable for study (2); carbon-14 also increases, but its relative rarity means its increase is negligible. After this point, other Absolute Dating methods may be used.Today, the radiocarbon-14 dating method is used extensively in environmental sciences and in human sciences such as archaeology and anthropology.Instruments working at lower energies cannot make such sharp distinctions. Donahue said that in dealing with a postage stamp-size sample from the shroud, the linen was first ''carefully cleaned, using both chemical and mechanical methods.'' Next, the sample was burned in oxygen, thereby converting the carbon in its molecules into carbon dioxide gas.The gas was then reduced to pure carbon in the form of graphite by heating the gas in the presence of iron powder.This is a digitized version of an article from The Times’s print archive, before the start of online publication in 1996.
The three laboratories conducting the analyses were at the University of Arizona in Tucson, the British Museum in London and the Swiss Federal Institute in Zurich.The Shroud of Turin was identified as a medieval forgery using a very sensitive dating technique available to only half a dozen laboratories around the world.In common with traditional dating techniques, the method used to determine the age of the shroud is based upon the slow decay of a radioactive form of carbon called carbon 14.Finally, the electrically charged carbon atoms emerging from the accelerator were sorted out by magnetic fields, permitting precise measurement of the ratio between carbon 14 and carbon 13.From this, scientists concluded that the flax plants from which the linen in the Shroud of Turin was made were grown in medieval times, long after the death of Jesus.