Mainz 2012 – scientific programme

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HK: Fachverband Physik der Hadronen und Kerne

HK 49: Poster – Astroteilchenphysik

HK 49.2: Poster

Thursday, March 22, 2012, 14:00–16:00, P Foyer

Assembling and Improvement of a 2-phase Xe TPC for electron drift length measurements — •Sonja Esch, Ethan Brown, Volker Hannen, Christian Huhmann, Hans Kettling, Stephan Rosendahl, Johannes Schulz, and Christian Weinheimer — Institut für Kernphysik, Universität Münster

About 22 % of the universe consists of a new undetected form of matter called dark matter(DM). One highly theoretically motivated candidate for dark matter is the Weakly Interacting Massive Particle (WIMP) from super symmetry. The XENON program looks for these particles by nuclear recoils in liquid xenon in a 2-phase time projection chamber(TPC).

Particle interactions in liquid xenon produce scintillation and ionization. The ionization is drifted then converted to secondary scintillation signal and both are detected by photo multiplier tubes (pmts). Electronegative impurities inhibit the detection of these signals, and radioactive impurities can mimic a DM signal. A small TPC has been built in Münster and implemented in a cryogenic purification system.

The efficiency of purification is tested using γ-sources and measuring the resulting signals. The evolution of purity over time is analyzed. A characterization of the TPC is possible by introducing radioactive tracers to the liquid phase. For reduction of radioactive impurities a distillation column is planned. Its efficiency can be tested using the TPC. First results of the characterization of the TPC will be shown. This project is supported by DFG and the state NRW, contract number INST 211/528-1 FUGG and by BMBF under 05A11PM1 .