Hamburg 2016 – wissenschaftliches Programm
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T: Fachverband Teilchenphysik
T 39: Suche nach dunkler Materie II
T 39.7: Vortrag
Montag, 29. Februar 2016, 18:20–18:35, VMP9 SR 28
Measuring radon reduction in xenon boil-off gas — Stefan Bruenner, •Dominick Cichon, Sebastian Lindemann, Teresa Marrodán Undagoitia, and Hardy Simgen — MPIK, Heidelberg, Germany
222Rn, which originates from the decay of primordial 238U, is one of the major background sources for ultra-low background noble gas detectors. One of them is XENON1T, which is a dark matter direct detection experiment looking for hypothetical weakly interacting massive particles (WIMPs). It uses liquid xenon (LXe) as a detection medium and aims to be sensitive to spin-independent WIMP-nucleon cross-sections of σ ∼ 2 · 10−47 cm2 at a WIMP mass of ∼ 50 GeV/c2. To achieve this goal, radon activity inside the detector must be limited to a few mBq/kg.
One possible way for reducing the concentration of 222Rn inside such an LXe detector is using the so-called "boil-off method". It takes advantage of the fact, that the radon concentration in boil-off xenon is smaller compared to the concentration in the liquid xenon from which the boil-off xenon evaporated. This can be understood by the different vapor pressures of radon and xenon. In this talk, tests conducted at the MPIK are outlined which probe the feasibility and effectiveness of the boil-off method. The results prove, that a reduction of the radon concentration can indeed be achieved. In addition, an outlook for possible future applications of this technique is given.