By applying magnetic and electrical fields, the mass of these ions is measured and the accelerator is used to remove ions that might contaminate the dating.
The sample passes through several accelerators in order to remove as many atoms as possible until the C pass into the detector.
The unstable nature of carbon 14 (with a precise half-life that makes it easy to measure) means it is ideal as an absolute dating method.
Typically (6): The above list is not exhaustive; most organic material is suitable so long as it is of sufficient age and has not mineralised - dinosaur bones are out as they no longer have any carbon left.
Stone and metal cannot be dated but pottery may be dated through surviving residue such as food particles or paint that uses organic material (8).
It is oxidised quickly and absorbed in great quantities by all living organisms - animal and plant, land and ocean dwelling alike.
When an organism dies, it stops absorbing the radioactive isotope and immediately starts decaying (7).
Very old trees such as North American Bristlecone Pine are ideal for constructing long and accurate records of the state of the atmosphere.
This allows researchers to account for variation by comparing the known records of C levels in the tree record, looking for a tree record that has the same proportion of radiocarbon.
Increasingly though, students are learning about the principles of radiocarbon dates in archaeology, palaeontology and climate science degrees and can combine cross-disciplinary studies.
The method developed in the 1940's and was a ground-breaking piece of research that would change dating methods forever. Libby calculated the rate of radioactive decay of the C isotope (4) in carbon black powder.
These latter atoms are used as part of the calibration process to measure the relative number of isotopes (9).
When the half-life was corrected in 1950, the year was taken as a base date from which to calculate all resulting dates.
Today, the radiocarbon-14 dating method is used extensively in environmental sciences and in human sciences such as archaeology and anthropology.