Mainz 2012 – scientific programme

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HK: Fachverband Physik der Hadronen und Kerne

HK 63: Astroteilchenphysik

HK 63.7: Talk

Friday, March 23, 2012, 15:30–15:45, RW 3

Purification Methods for Xenon — •Stephan Rosendahl, Ethan Brown, Volker Hannen, Christian Huhmann, Hans Kettling, Johannes Schulz, and Christian Weinheimer — Institut für Kernphysik, Universität Münster

The Xenon Project uses a 2 phase time projection Chamber (TPC) to search for dark matter by detecting a nuclear recoil signal, induced by Weakly Interacting Massive Particles (WIMPs). An interaction between WIMPS and the target nuclei produces scintillation and charge signals. The electrons are drifted in an electric field to the gas phase where they are extracted to produce fluorescence light in xenon gas. Both light signals are detected by arrays of photomultiplier tubes on the top and bottom of the detector. The drift length of the electrons in liquid xenon strongly depends on the content of electronegative impurities. Furthermore Kr-85, which contributes to radioactive backgrounds, must be removed from the commercial xenon to the ppt level.

In Münster we set up a system to remove the electronegative impurities with a zirconium purifier and using cryogenic distillation to remove Kr-85 isotopes from the xenon. The quality of the xenon is investigated, using a dual phase xenon TPC, in combination with a laser based moisture analyzer and a quadrupol mass filter to have a complementary setup of different tools. The whole system is designed to perform R&D studies for the Xenon1T experiment, which is the next generation of direct dark matter detectors.

The project is supported by DFG and the state NRW, contractnumber INST 211/528-1 FUGG and by BMBF, number 05A11PM1.