Accelerator Mass Spectrometry
Definition
A mass spectrometer fronted by a high-energy particle accelerator (typically a 500 keV to 6 MeV tandem). Counts individual carbon-14 atoms directly rather than waiting for them to decay. Needs only a milligram of carbon and a few hours of run time, against grams and weeks for conventional liquid scintillation. The modern global standard for radiocarbon dating, including for questioned documents.
Related terms
- Becquerel and Curie
- The becquerel (Bq) is one nuclear disintegration per second, the SI unit of activity. The older curie (Ci) is 3.7 × 10^10...
- Geiger-Muller Tube
- A gas-filled cylindrical tube with a thin entrance window and a high-voltage central wire. An ionising particle entering the tube triggers a...
- Half-Life
- The time required for half the radioactive atoms in a sample to decay. Set by the decay constant lambda through t1/2 =...
- HPGe Detector
- A high-purity germanium semiconductor crystal cooled with liquid nitrogen to about 77 kelvin. Resolution at the 1,332 keV gamma line of cobalt-60...
- Scintillation Detector
- A crystal or liquid (sodium iodide doped with thallium for gamma, an organic cocktail for low-energy beta) that emits visible-light flashes when...
Explained in
- Radiochemistry: Radioactivity, Carbon Dating, Neutron ActivationA mass spectrometer fronted by a high-energy particle accelerator (typically a 500 keV to 6 MeV tandem). Counts individual carbon-14 atoms directly rather than...