During the lifetime of an organism, the amount of c14 in the tissues remains at an equilibrium since the loss (through radioactive decay) is balanced by the gain (through uptake via photosynthesis or consumption of organically fixed carbon).
However, when the organism dies, the amount of c14 declines such that the longer the time since death the lower the levels of c14 in organic tissue.
The archaeological site of Mezhirich (sometimes spelled Mezhyrich) is an Upper Paleolithic (Epigravettian) site located in the Middle Dnepr (or Dneiper) Valley region of Ukraine near Kiev, and it is one of the best-preserved sites of its type excavated to date.
The AMS Laboratory was founded in 1981 by Professors Douglas J. Damon (Geosciences) with support from the National Science Foundation.
The measurement of radiocarbon by mass spectrometry is very difficult because its concentration is less than one atom in 1,000,000,000,000.
The accelerator is used to help remove ions that might be confused with radiocarbon before the final detection.
Since carbon is fundamental to life, occurring along with hydrogen in all organic compounds, the detection of such an isotope might form the basis for a method to establish the age of ancient materials.
Libby, a Professor of Chemistry at the University of Chicago, predicted that a radioactive isotope of carbon, known as carbon-14, would be found to occur in nature.