What is radiocarbon dating used for
An accelerator mass spectrometer, although a powerful tool, is also a costly one.
Establishing and maintaining an accelerator mass spectrometer costs millions of dollars.
Ions from a cesium gun are then fired at the target wheel, producing negatively ionized carbon atoms.
These negatively ionized carbon atoms pass through focusing devices and an injection magnet before reaching the tandem accelerator where they are accelerated to the positive terminal by a voltage difference of two million volts.
Radiometric dating methods detect beta particles from the decay of carbon 14 atoms while accelerator mass spectrometers count the number of carbon 14 atoms present in the sample.
Both carbon dating methods have advantages and disadvantages.
These two radiocarbon dating methods use modern standards such as oxalic acid and other reference materials.
Although both radiocarbon dating methods produce high-quality results, they are fundamentally different in principle.
The first part involves accelerating the ions to extraordinarily high kinetic energies, and the subsequent step involves mass analysis.
Accelerator mass spectrometers need only as little as 20 milligrams and as high as 500 milligrams for certain samples whereas conventional methods need at least 10 grams in samples like wood and charcoal and as much as 100 grams in bones and sediments.
Accelerator mass spectrometers typically need sample sizes lesser than conventional methods by a factor of 1,000. Hence, because of its ability to analyze samples even in minute amounts, accelerator mass spectrometry is the method of choice for archaeologists with small artifacts and those who cannot destroy very expensive or rare materials.
After pretreatment, samples for radiocarbon dating are prepared for use in an accelerator mass spectrometer by converting them into a solid graphite form.
This is done by conversion to carbon dioxide with subsequent graphitization in the presence of a metal catalyst.