Start Radiocarbon dating of the iceman otzi with accelerator mass spectrometry

Radiocarbon dating of the iceman otzi with accelerator mass spectrometry

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.

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.

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.

In this method, the carbon 14 content is directly measured relative to the carbon 12 and carbon 13 present. Some inorganic matter, like a shell’s aragonite component, can also be dated as long as the mineral’s formation involved assimilation of carbon 14 in equilibrium with the atmosphere.

When they die, they stop exchanging carbon with the biosphere and their carbon 14 content then starts to decrease at a rate determined by the law of radioactive decay.

Radiocarbon dating is essentially a method designed to measure residual radioactivity.

As a result it is always undergoing natural radioactive decay while the abundances of the other isotopes are unchanged.

Carbon-14 is most abundant in atmospheric carbon dioxide because it is constantly being produced by collisions between nitrogen atoms and cosmic rays at the upper limits of the atmosphere.

The method does not count beta particles but the number of carbon atoms present in the sample and the proportion of the isotopes. Samples that have been radiocarbon dated since the inception of the method include charcoal, wood, twigs, seeds, bones, shells, leather, peat, lake mud, soil, hair, pottery, pollen, wall paintings, corals, blood residues, fabrics, paper or parchment, resins, and water, among others.