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IGERT program in Archeological Science

Principles of AMS

Radiocarbon dating





Age Calculation


Cosmogenic Radioisotopes



     Radiocarbon dating using Accelerator Mass Spectrometry (AMS) differs from the decay counting methods in that the amount of 14C in the sample is measured directly, rather than by waiting for the individual radioactive decay events to occur. This makes the technique 1,000 to 10,000 times more sensitive than decay counting. The enhanced sensitivity is achieved by accelerating sample atoms as ions to high energies using a particle accelerator, and using nuclear particle detection techniques. A photograph and a schematic diagram of the new 3 MV AMS machine at the University of Arizona are shown below.

detector detector detector detector 15 degree deflector magnet magnet magnet 15 degree deflector 15 degree deflector stripper gas stripper gas pelletron pelletron 90 degree injection magnet 90 degree injection magnet 90 degree injection magnet ion source ion source ion source

Schematic diagram of the 3 MV Pelletron system,
constructed by National Electrostatics Corporation (Middleton, WI).

Click on the diagram for text explanation