Figure 3
From: Recent advances in biomedical applications of accelerator mass spectrometry
Bomb curve used for dating recent biological materials. The levels of 14C in the atmosphere have been relatively stable over long time periods, with the exception that atmospheric nuclear weapons tests in 1955–1963 added significant amounts of 14C to the environment. *The age of the biological material is calculated based on an assumption that the organism's biosynthesis is in isotopic equilibrium with its carbon sources. Choosing between the two dates requires additional data.