Interpretation of  Accelerator Mass Spectroscopy

  Rare isotopes analyzed by AMS are always measured as a ratio of a stable, more abundant (but not too abundant) isotope. For example, the ratio in ¹⁴C studies is generally shown as ¹⁴C/¹³C. Less abundant isotopes are preferable in AMS because the decreased flux of ions reduces background and wear on the instrument, which is of particular concern due to the quick deterioration of particle detectors (performance deteriorates at rates higher than a few thousand particles per second)