Dating artifacts methods
There are two techniques in measuring radiocarbon in samples—through radiometric dating and by Accelerator Mass Spectrometry (AMS).
The two techniques are used primarily in determining carbon 14 content of archaeological artifacts and geological samples.
Mass spectrometers detect atoms of specific elements according to their atomic weights.
They, however, do not have the sensitivity to distinguish atomic isobars (atoms of different elements that have the same atomic weight, such as in the case of carbon 14 and nitrogen 14—the most common isotope of nitrogen).
The first part involves accelerating the ions to extraordinarily high kinetic energies, and the subsequent step involves mass analysis.After pretreatment, samples for radiocarbon dating are prepared for use in an accelerator mass spectrometer by converting them into a solid graphite form.Thanks to nuclear physics, mass spectrometers have been fine-tuned to separate a rare isotope from an abundant neighboring mass, and accelerator mass spectrometry was born.A method has finally been developed to detect carbon 14 in a given sample and ignore the more abundant isotopes that swamp the carbon 14 signal.
There are two accelerator systems commonly used for radiocarbon dating through accelerator mass spectrometry.One is the cyclotron, and the other is a tandem electrostatic accelerator.