Mainz 2012 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 18: Instrumentation

HK 18.6: Vortrag

Dienstag, 20. März 2012, 18:15–18:30, P 2

Gas Purity Analysis for the Xenon Dark Matter Project — Ethan Brown, Sonja Esch, Volker Hannen, Christian Huhmann, •Hans Kettling, Stephan Rosendahl, Johannes Schulz, and Christian Weinheimer — Institut für Kernphysik, Universität Münster

The XENON Project searches 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). The efficiency of the detector strongly depends on the purity of the xenon. Therefore the Muenster group develops among other things a Krypton distillation column in order to reduce the level of Krypton contamination to the low ppt range. This is necessary, as β-decay of ⁸⁵Kr constitutes one of the dominant backgrounds of the experiment.

In my talk a purity analysis of Xenon gas will be presented. In particular a mass spectrometry technique for measuring trace amounts of Krypton in Xenon down to the ppb and sub ppb range will be explained. The Sensitivity of the spectrometer is enhanced by orders of magnitude by the use of a cold trap with liquid nitrogen, exploiting the difference in vapor pressures of Krypton and Xenon at a temperature around 77 Kelvin.

This work has been supported by DFG (for XENON100, GZ: WE1 843/7-1) and BMBF (for XENON1T, GZ: 05A11PM1).