WHAT IT IS
The primary beam is composed of ions extracted from the ion source, typically derived from the sample being analyzed. These ions are accelerated to form a focused beam with controlled energy, composition, and intensity, ensuring optimal conditions for isotopic separation and analysis. The quality and stability of the primary beam directly impact the performance of the AMS system. Most AMS systems generate negative ion beams, as they help eliminate certain molecular interferences (e.g., 14N for 14C dating). Cesium sputter ion sources are commonly used for producing stable, high-yield negative ions.
HOW IT WORKS
Ion Generation – The sample material is bombarded by electrons, cesium ions, or plasma to create a beam of ions.
Ion Selection – The generated ions are filtered to select the desired charge state and isotope of interest.
Acceleration – The ions are accelerated by high voltages, gaining sufficient energy for isotopic separation and interference removal.
Beam Focusing – Ion optics focus the primary beam into a narrow and well-defined trajectory, minimizing losses.
Isotopic Separation – The ions in the primary beam are separated by their mass-to-charge ratio (m/z) in the tandem accelerator and magnetic analyzers.