In order to measure radiocarbon ages it is necessary to find the amount of radiocarbon in a sample. This measurement can be made either by measuring the radioactivity of the sample the conventional beta -counting method or by directly counting the radiocarbon atoms using a method called Accelerator Mass Spectrometry AMS. Measurement of the radioactivity of the sample works very well if the sample is large, but in 9 months less than 0. The method is relatively new because it needs very complicated instruments first developed for Nuclear Physics research in the late 20th century. In common with other kinds of mass spectrometry, AMS is performed by converting the atoms in the sample into a beam of fast moving ions charged atoms.
Cavity spectroscopy does carbon dating
Radiocarbon WebInfo - AMS
An accelerator mass spectrometer measures the amounts of different isotopes within a sample. For carbon dating, the process starts in an ionizing chamber, where the atoms within a sample of pure carbon are given a negative charge. An accelerator then increases the kinetic energy of the carbon ions to million electron volts and moves them through a tube where a powerful electromagnet makes them change direction. How much their path bends depends on their mass: Lighter ions bend more. This separates the three isotopes of carbon.
Radiocarbon dating is a method that provides objective age estimates for carbon-based materials that originated from living organisms. The impact of the radiocarbon dating technique on modern man has made it one of the most significant discoveries of the 20th century. Archaeology and other human sciences use radiocarbon dating to prove or disprove theories. Over the years, carbon 14 dating has also found applications in geology, hydrology, geophysics, atmospheric science, oceanography, paleoclimatology and even biomedicine.
Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It only takes a minute to sign up. My understanding of the limitation of radiometric dating is that background radiation swamps the radiation from C14 once the remaining atoms get few enough in number. Accelerator mass spectrometry seems to actually count every atom in the sample, meaning background radiation doesn't matter. Yet the advantage of AMS dating stated here is "can use smaller sample size", not "can give dates much farther into the past using the same sample size".