The resulting data, in the form of a calibration curve, is now used to convert a given measurement of radiocarbon in a sample into an estimate of the sample's calendar age.
Other corrections must be made to account for the proportion of throughout the biosphere (reservoir effects).
For example, two samples taken from the tombs of two Egyptian kings, Zoser and Sneferu, independently dated to 2625 BC plus or minus 75 years, were dated by radiocarbon measurement to an average of 2800 BC plus or minus 250 years. Carbon dioxide produced in this way diffuses in the atmosphere, is dissolved in the ocean, and is taken up by plants via photosynthesis.
Animals eat the plants, and ultimately the radiocarbon is distributed throughout the biosphere.
They synthesized Libby and several collaborators proceeded to experiment with methane collected from sewage works in Baltimore, and after isotopically enriching their samples they were able to demonstrate that they contained radioactive .
By contrast, methane created from petroleum showed no radiocarbon activity because of its age.
In these studies, both old Russian and old Middle Eastern (En Gedi, Israel,100) linen textile samples were tested by near-IR reflectance spectrophotometry, field ionization/field desorption mass spectrometry, and conventional AMS analysis.
In 1939, Martin Kamen and Samuel Ruben of the Radiation Laboratory at Berkeley began experiments to determine if any of the elements common in organic matter had isotopes with half-lives long enough to be of value in biomedical research.Measurement of radiocarbon was originally done by beta-counting devices, which counted the amount of beta radiation emitted by decaying atoms in the sample and not just the few that happen to decay during the measurements; it can therefore be used with much smaller samples (as small as individual plant seeds), and gives results much more quickly.The development of radiocarbon dating has had a profound impact on archaeology.A laboratory model especially created to “reproduce”, i.e.to simulate the physical/chemical conditions of the 1532 Chambéry fire was developed for the purpose of determining experimentally the probability that fire-induced chemical modifications of the Turin Shroud textile cellulose had occurred and evaluating its possible impact on the radiocarbon dating results.
As seen from the resulting data, fire-induced carboxylation, i.e.