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HK: Fachverband Physik der Hadronen und Kerne

HK 35: Astroteilchenphysik - Poster

HK 35.2: Poster

Mittwoch, 23. März 2011, 14:00–16:00, Foyer Chemie

Gas purification for the XENON Project — •Hans Kettling, Stephan Rosendahl, Ethan Brown, Volker Hannen, Christian Huhmann, Johannes Schulz, and Christian Weinheimer — Institut für Kernphysik, Universität Münster, Germany

The XENON Project will search for dark matter by detecting the nuclear recoil signal induced by a Weakly Interacting Massive Particle (WIMP) in a 2 phase xenon time projection chamber (TPC). Interactions in the liquid phase cause scintillation and ionization signals. The electrons are drifted from the liquid into the gaseous phase and accelerated there, causing fluorescence light. Both light signals are detected by arrays of photosensitive detectors.
The drift length of the electrons strongly depends on the purity of the xenon. In particular oxygen molecules reduce the electron drift length, as they absorb electrons. Therefore, our group designs and tests cryogenic purification systems for xenon in the gaseous and liquid phase.
A SAES getter is used to remove electronegative elements in the gaseous phase such as oxygen or hydrocarbons.
The purification systems will also comprise a distillation column in order to reduce the level of the ⁸⁵Kr contamination to the low ppt range. This is necessary, as β-decay of ⁸⁵Kr constitutes one of the backgrounds of the experiment.
We will use ^83mKr as a tracer to optimize the Xe to Kr separation.
This work is supported by DFG and the state NRW under contract INST 211/528-1 FUGG.