Carbon dating paper
It is presumed that the proportion of atmospheric C is the same today as it was in 1950 (10), (11) and that the half-life remains the same.If a radioactivity level comes back as half of what would have been expected if the organism had died in 1950, then it is presumed to be 5,730 years before 1950.
When an organism dies, it stops absorbing the radioactive isotope and immediately starts decaying (7).
As previously mentioned, the half life of the C isotope is 5,730 years - this means that it takes 5,730 years to reach half the radioactivity that the organism had at the point of death, another 5,730 years to reach 25% radioactivity it had at the point of death and so on.
Archaeologists had used Relative Dating methods to calculate their reigns.
Though their initial calculations were slightly incorrect thanks to the contaminants of extensive nuclear testing of the age, scientists soon discovered the error and developed methods that were more accurate, including a date of calibration to 1950.
AMS works slightly differently; it converts the atoms of the sample into fast-moving ions so that they become charged atoms.