Waikato radiocarbon dating laboratory
What you’re doing is measuring all of the carbon isotopes in the sample – the 12, 13 and 14 – the accelerator operates like a giant mass spectrometer.A mass spectrometer is an instrument that uses a series of magnets to bend a beam of ions and then physically count how many there are, so with AMS radiocarbon dating, we can measure a carbon-12, 13 and 14 beam, and we measure the ratio of 14 to 13, and from that, we can tell how much C-14 is in the sample.The 6 proton 6 neutron atoms are said to have a mass of 12 and are referred to as "carbon-12." The nuclei of the remaining one percent of carbon atoms contain not six but either seven or eight neutrons in addition to the standard six protons.They have masses of 13 and 14 respectively and are referred to as "carbon-13" and "carbon-14." If two atoms have equal numbers of protons but differing numbers of neutrons, one is said to be an "isotope" of the other.Carbon-13 and carbon-14 are thus isotopes of carbon-12.Isotopes participate in the same chemical reactions but often at differing rates.This fragment no bigger than a fingernail is enough to divine whether the artefact it came from is really the Roman musical instrument its owners believe it to be.Lab manager Dr Christine Prior already has bad news for another client – an art authenticator in Hong Kong.
Research at the University of Waikato’s Radiocarbon Dating Laboratory in New Zealand has concentrated on the application of radiocarbon and chemical characterization techniques to improve the reliability of archaeological results and chronologies.All carbon atoms have a nucleus containing six protons.Ninety-nine percent of these also contain six neutrons.The C-14 decays with the beta particle, and you have some detection equipment and you count the C-14s one by one.
Accelerator mass spectrometry is not dependent upon the radioactive decay.
So the most important things about AMS radiocarbon dating as opposed to conventional is that the sample size is much, much smaller.