Accelerator mass spectrometry

Accelerator mass spectrometry (AMS) is a form of mass spectrometry that accelerates ions to extraordinarily high kinetic energies before mass analysis. The special strength of AMS among the different methods of mass spectrometry is its ability to separate a rare isotope from an abundant neighboring mass ("abundance sensitivity", e.g. ¹⁴C from ¹²C). The method suppresses molecular isobars completely and in many cases can also separate atomic isobars (e.g. ¹⁴N from ¹⁴C). This makes possible the detection of naturally occurring, long-lived radio-isotopes such as ¹⁰Be, ³⁶Cl, ²⁶Al and ¹⁴C. (Their typical isotopic abundance ranges from 10⁻¹² to 10⁻¹⁸.)

AMS can outperform the competing technique of decay counting for all isotopes where the half-life is long enough. Other advantages of AMS include its short measuring time as well as its ability to detect atoms in extremely small samples.