The analysis by means of carbon 14 allows a precise dating of the works. Carbon 14 dating is applied to organic material from living organisms (wood, textiles, ivory, bones, shells…). It makes it possible to determine the moment of death of the organism which corresponds to the tree’s felling, the cutting of the plants or the death of the living being.
Carbon is a radioactive element and its radioactivity decreases over time at a regular rate according to a known process. Indeed, during the life of an organism, the relative concentration of carbon 14 it contains is constant due to respiration, feeding, photosynthesis or any other interaction with the biosphere. At its death, exchanges cease and the concentration of radioactive carbon 14 decreases at a rate of about half every 5500 years.
RES uses it to estimate the age, and therefore the date of realization of a work.
A fragment or a sample of a few tens of milligrams is taken from the artwork or archaeological object and then vaporized. The concentration of carbon 14 is then determined using a mass spectrometer (which allows the separation of atoms according to their mass and valence), by comparison with measurements obtained on standards. Calibration procedures and taking into account possible reservoir effects allow the raw age to be transformed into calendar date interval.