Accelerator mass spectrometry dating
All of the molecular ions (such as Careful sampling and pre-treatment are very important stages in the dating process, particularly for archaeological samples where there is frequently contamination from the soil.
Before sampling, the surface layers are usually removed because these are most susceptible to contamination.
The carbon isotope ratio can also be used to correct for isotopic fractionation in the radiocarbon measurement.
Radiocarbon dating research has been part of the University of Arizona since 1954.Only very small quantities are required for the AMS measurement (30ug-3mg of carbon) and so the damage to objects can be minimised.The chemical pre-treatment depends on the type of sample.The best conventional counters can still achieve higher precision and lower backgrounds than an AMS system assuming a suitably large pure sample can be found.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.