MODEL RELEASED. Accelerator mass spectrometer (AMS) used for carbon dating. The AMS converts atoms from a sample into a beam of ions,which are accelerated along this tube,the linear accelerator. It then measures the mass of the ions by the application of electric and magnetic fields. All living material incorporates a radioactive isotope of carbon,carbon-14 (14C),and a stable isotope,carbon-12 (12C),into its tissue at a known ratio. When the tissue dies the amount of 12C remains constant,but 14C decays. Measuring the amount of 14C compared to 12C in a sample indicates how long ago the tissue died. Photographed at Oxford Radiocarbon Accelerator Unit,University of Oxford,UK |