Accelerator mass spectrometry dating
The method is relatively new because it needs very complicated instruments first developed for Nuclear Physics research in the late 20th century.
The ions produced are negative which prevents the confusion of ions). As they travel to the terminal (which is at about 2MV), they are accelerated so much that when they collide with the gas molecules in the central `stripper canal'.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.The mass of these ions is then measured by the application of magnetic and electric fields.The measurement of radiocarbon by mass spectrometry is very difficult because its concentration is less than one atom in 1,000,000,000,000.