Dating method based on rate of decay of radioactive isotopes
There are three principal techniques used to measure carbon 14 content of any given sample— gas proportional counting, liquid scintillation counting, and accelerator mass spectrometry.
Gas proportional counting is a conventional radiometric dating technique that counts the beta particles emitted by a given sample. In this method, the carbon sample is first converted to carbon dioxide gas before measurement in gas proportional counters takes place.
An age could be estimated by measuring the amount of carbon-14 present in the sample and comparing this against an internationally used reference standard.
The impact of the radiocarbon dating technique on modern man has made it one of the most significant discoveries of the 20th century.
Accelerator mass spectrometry (AMS) is a modern radiocarbon dating method that is considered to be the more efficient way to measure radiocarbon content of a sample.
These values have been derived through statistical means.
It is rapidly oxidized in air to form carbon dioxide and enters the global carbon cycle.
Plants and animals assimilate carbon 14 from carbon dioxide throughout their lifetimes.
By knowing how much carbon 14 is left in a sample, the age of the organism when it died can be known.
It must be noted though that radiocarbon dating results indicate when the organism was alive but not when a material from that organism was used.