Carbon dating notes
Other atoms are also named based on the number of protons they carry.
Notice in the diagram that eight different isotopes of Carbon are illustrated.
Three of the Carbon isotopes (C) are found in nature.
The rest of the carbon isotopes are only of laboratory interest.
Carbon-14 was discovered on 27 February 1940, by Martin Kamen and Sam Ruben at the University of California Radiation Laboratory in Berkeley, California.
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.
The fraction of the radiation transmitted through the dead skin layer is estimated to be 0.11.