Atoms are sputtered from the sample by cesium ions which are produced on a hot spherical ionizer and focused to a small spot on the sample.
Negative ions produced on the surface of the sample are extracted from the ion source and sent down the evacuated beam line towards the first magnet.
Definition: AMS (Accelerator Mass Spectrometry) radiocarbon dating is a way to obtain radiocarbon dates from samples that are far tinier than that needed for standard radiocarbon dating.
Standard c14 dates require amounts of between 1 and 10 grams of charcoal; AMS can use as little as 1-2 milligrams, and under special circumstances to samples as small as 50-100 micrograms.
At the terminal they pass through either a very thin carbon film or a tube filled with gas at low pressure (the stripper), depending on the particular accelerator.
Collisions with carbon or gas atoms in the stripper remove several electrons from the carbon ions, changing their polarity from negative to positive. The positive ions are then accelerated through the second stage of the accelerator, reaching kinetic energies of the order of 10 to 30 million electron volts. This problem is solved in the tandem accelerator at the stripper –if three or more electrons are removed from the molecular ions the molecules dissociate into their component atoms. The kinetic energy that had accumulated up to now is distributed among the separate atoms, none of which has the same energy as a single C from the more intense "background" caused by the dissociated molecules on the basis of their kinetic energy.
The element is first chemically extracted from the sample (for example, a rock, rain water, a meteorite) then it is loaded into a copper holder and inserted into the ion source through a vacuum lock.In standard radiocarbon dating, scientists perform a limited or proportional count of the decaying C14 atoms.In AMS dating, researchers use an accelerator-based mass spectrometer to count all the C14 atoms, rather than just those atoms which are decaying.They are used for a wide variety of dating and tracing applications in the geological and planetary sciences, archaeology, and biomedicine.The following is a brief description of each element of the AMS system.At this point the beam is about 10 microamps which corresponds to 10 ions per second (mostly the stable isotopes).