ABSTRACT
Radiocarbon undergoes negative beta decay in which the mass number remains unchanged but the atomic number increases by one. The types of Radioactivity measurement instruments: ionizing radiation detection and mass spectrometric detection. The challenge of accurately and precisely measuring naturally occurring 14C concentrations proceeds from the consequences of three interconnected physical realities. First, natural, cosmic-ray-produced 14C occurs in extremely low concentrations in natural samples. Second, since beta particles are fundamentally electrons emitted from a nucleus during decay, they exhibit a range of energies. Third, 14C is a relatively long-lived nuclide. Until the late 1970s, all routine natural-level 14C measurements were obtained using various types of decay counting instrumentation. They are Solid Carbon decay, Gas Proportional decay and Liquid Scintillation Counting. The development of accelerator mass spectrometry (AMS) technology as a means of measuring natural levels of 14C has been characterized as the "Third Radiocarbon Revolution".
