アイテム詳細

要旨

Dark matter direct detection experiments require a substantial background reduction to reach the sensitivity needed for the observation of interaction processes with very low event rates. The Xenon1T experiment uses liquid xenon as a target material for scattering events of Weakly Interacting Massive Particles (WIMPs), that are favoured candidates as particle dark matter. The radioactive isotope of radon (²²²Rn) is one of the most serious intrinsic background sources, since it can be emanated from all materials in the detector. As a noble gas, it is distributed homogeneously inside the liquid xenon, where the subsequent decays of its daughter isotopes can mimic the expected WIMP signal. In this thesis, an experimental setup to measure radon emanation is employed to study the effect of coating on a contaminated material to prevent radon from emanation. Different coating techniques and materials are analysed and the individual results will be discussed. The final result of the emanation reduction achieved by coating will be shown, with an estimation on the improved radon background of Xenon1T as a possible application for XenonNT. Additionally, a set of measurements was done to further improve the detection of ²²²Rn with proportional counters, by determining detection efficiency for radon and its progenies.