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.

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.

At this stage, other negatively charged atoms are unstable and cannot reach the detector.

The negatively charged carbon atoms, however, move on to the stripper (a gas or a metal foil) where they lose the electrons and emerge as the triple, positively charged carbon atoms.

Reference materials are also pressed on metal discs.

These metal discs are then mounted on a target wheel so they can be analyzed in sequence.

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).

In mass analysis, a magnetic field is applied to these moving charged particles, which causes the particles to deflect from the path they are traveling.

If the charged particles have the same velocity but different masses, as in the case of the carbon isotopes, the heavier particles are deflected least.

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.

Burning the samples to convert them into graphite, however, also introduces other elements into the sample like nitrogen 14.