Its existence had been suggested by Franz Kurie in 1934. The primary natural source of carbon-14 on Earth is cosmic ray action on nitrogen in the atmosphere, and it is therefore a cosmogenic nuclide.
However, open-air nuclear testing between 1955–1980 contributed to this pool.
When these energetic neutrons collide with a nitrogen-14 (seven protons, seven neutrons) atom it turns into a carbon-14 atom (six protons, eight neutrons) and a hydrogen atom (one proton, zero neutrons).
Ionization Inverse Square Law Interaction of RT/Matter Attenuation Coefficient Half-Value Layer Sources of Attenuation -Compton Scattering Geometric Unsharpness Filters in Radiography Scatter/Radiation Control Radiation Safety Radio-carbon dating is a method of obtaining age estimates on organic materials.
Its presence in organic materials is the basis of the radiocarbon dating method pioneered by Willard Libby and colleagues (1949) to date archaeological, geological and hydrogeological samples.
Carbon-14 was discovered on 27 February 1940, by Martin Kamen and Sam Ruben at the University of California Radiation Laboratory in Berkeley, California.
The word "estimates" is used because there is a significant amount of uncertainty in these measurements.
Each sample type has specific problems associated with its use for dating purposes, including contamination and special environmental effects.