The ion source produces a beam of ions (atoms that carry an electrical charge) from a few milligrams of solid material.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.These ratios provide useful information on the purity of the sample and clues about the diet and climatic conditions of the living organism.The carbon isotope ratio can also be used to correct for isotopic fractionation in the radiocarbon measurement.In AMS the radiocarbon atoms are directly detected instead of waiting for them to decay.

A small amount of this gas is bled into a mass spectrometer where the stable isotope ratios of carbon and nitrogen are measured.

For this reason, the calibration curves for radiocarbon have usually been measured using counters. Many of these perform radiocarbon measurements and some of them will undertake sample pre-treatment.

Accelerator mass spectrometry (AMS) is a technique for measuring long-lived radionuclides that occur naturally in our environment.

In common with other kinds of mass spectrometry, AMS is performed by converting the atoms in the sample into a beam of fast moving ions (charged atoms).

The mass of these ions is then measured by the application of magnetic and electric fields.