C14

There are many different archeological methods used during the investigation of the legend of King Arthur. The most important method is radiocarbon dating, which uses the radioisotope carbon-14. The used radiocarbon dating, like we said before, with the dating of the Round Table in Winchester Castle1. So we decided to focus only on
14
C.

General Information about 14 C2

14 C is a radioisotope of 12 C which radiates beta decay. In the atmosphere there are three types of carbon atoms; 12 C, 13 C and 14 C. 98,9% is 12 C, 1,1% is 13 C and
only 1 in every 1012 is 14 C.

14 C is caused by Cosmic radiation; particles (from the stars and the sun) which fly with a high speed into our atmosphere. Those particles get caught by the magnetic field of the earth. The particles collide with other atoms in the atmosphere, whereby so called “Cosmic isotopes” are being formed, including 14 C.

14 C and O2, which also appears in the atmosphere, form CO2 . CO2 is absorbed into plants through photosynthesis, with that the 14 C is absorbed as well. Animals and human eat plants, so we all absorb 14 C.

Once an organism dies, it will not absorb CO2 any longer, with that no 14 C either. That's when the 14 C – concentration will start decgreasing. So we can tell by the percentage of 14 C in a organism, how many years ago it died. That is the basic principle of radiocarbon dating. Every radioisotope has a radioactive half-life. 14 C has a radioactive half-life of 5730 years.

There are two different methods to determine the concentration 14 C: