Dresden 2014 – wissenschaftliches Programm

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VA: Fachverband Vakuumphysik und Vakuumtechnik

VA 2: Vacuum Gauges and Instrumentation

VA 2.2: Vortrag

Montag, 31. März 2014, 14:40–15:00, HSZ 105

Comparison of different mass spectrometers for fusion applications — •Katharina Battes, Christian Day, and Volker Hauer — Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen, Germany

For fusion applications, like e. g. for analysing tokamak exhaust gases, mass spectrometers could be used. But as the plasma pulses can be short (e.g. about 400 s for ITER), fast responding devices are needed. On the other hand also devices with a high resolution as well as a low detection limit are required, as He and D2 should be separated and small contents of impurities should be detected, respectively.

The fast response time can e.g. be achieved by an autoresonant ion trap mass spectrometer (Brooks 835 VQM), which can determine partial pressures from 1-300 amu in 120 ms. Like this online measurements are possible, but the fast scan time leads to a lack of resolution and sensitivity. Therefore a second device, a high resolution quadrupole mass spectrometer (Balzers GAM 400), is used for accurately determining partial pressures of different exhaust gases. Even He and D2 which both appear at a mass of about 4 amu can be separated and quantified. However, such a scan can only be performed a few times during a short pulse. As third device another QMS (MKS Microvision 2) is going to be tested. It operates only in the mass range from 1-6 amu and there achieves very high resolution.

This paper will present comparative measurements of expected exhaust gases and discuss the applicability of these three devices for online-mass spectrometry.