Progress in Accelerator Mass Spectrometry

ETH Zurich

The technical evolution of Accelerator Mass Spectrometry (AMS) instrumentation over the last ten years is summarized. A key characteristic of AMS is destruction of molecular interferences and subsequent analyses of atomic ions. It makes the extreme abundance sensitivity possible (in specific cases, below isotopic ratios of 10-16). This can be reached with instruments having quite modes mass resolving power (M/∆M less than 300). Today, 1+ charge state is used, molecular interferences are destroyed in multiple collisions with stripper gas atoms or molecules, and a high yield atomic ions is reached at energies of a few hundred keV.

Thus, AMS instruments develop towards lab size or tabletop devices. The use of He as stripper gas has further improved performance with respect to overall detection efficiency and reproducibility of measurement conditions. In parallel, implementation of permanent magnets into dedicated radiocarbon AMS system is progressed. This reduces complexity of the instruments and significantly reduces operation and installation costs. For radiocarbon, He stripping has potential to further down size instruments and reduce the ion energy below 50 keV. I will summarize the latest achievements.

But, low energy AMS is not limited to radiocarbon only and there is a great potential for 10Be, 26Al, 129I and actinides measurements at compact AMS systems. These developments have launched the wide spread use of AMS in various research fields and has resulted in a boom of new AMS facilities. The related impact to the wide variety of applications of AMS in modern research is not covered.