Mainz 2017 – scientific programme

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MS: Fachverband Massenspektrometrie

MS 9: Accelerator Mass Spectrometry and Applications II

MS 9.2: Talk

Thursday, March 9, 2017, 14:45–15:00, RW 2

Gas flow dynamics in an AMS stripper — •Sascha Maxeiner, Hans-Arno Synal, Marcus Christl, Lukas Wacker, and Andreas Herrmann — Laboratory for Ion Beam Physics (LIP), ETH Zurich, Switzerland

The stripper of an AMS system is required to strip off electrons from the incident negative ion beam and it is responsible for the dissociation of molecules. In low energy AMS gas strippers are widely applied. Besides their desired effects (charge exchange and molecule destruction) gas strippers can have a big influence on measurement sensitivity and background. For example, the interaction of incident ions with residual stripper gas outside of the stripper tube, e.g. during acceleration, is known to cause interferences which limit the abundance sensitivity.

In this presentation processes are discussed which can lead to increased leakage of stripper gas into the AMS beam line. Methods are presented to model these processes and an experimental setup is described to measure the gas leakage out of the stripper tube. The results of both, experiments and simulations are used to optimize the separation of stripper target and vacuum by designing new stripper geometries. As an example, the application of the optimization procedure to the TANDY AMS facility is presented and the potential of the new tool for optimization of existing systems is discussed.