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We describe the purification of xenon from traces of the radioactive noble gas radon using a cryogenic distillation column. The distillation column was integrated into the gas purification loop of the XENON100 detector for online radon removal. This enabled us to significantly reduce the constant [Formula omitted]Rn background originating from radon emanation. After inserting an auxiliary [Formula omitted]Rn emanation source in the gas loop, we determined a radon reduction factor of [Formula omitted] (95% C.L.) for the distillation column by monitoring the [Formula omitted]Rn activity concentration inside the XENON100 detector.

We describe the purification of xenon from traces of the radioactive noble gas radon using a cryogenic distillation column. The distillation column was integrated into the gas purification loop of the XENON100 detector for online radon removal. This enabled us to significantly reduce the constant 222 Rn background originating from radon emanation. After inserting an auxiliary 222 Rn emanation source in the gas loop, we determined a radon reduction factor of R > 27 (95% C.L.) for the distillation column by monitoring the 222 Rn activity concentration inside the XENON100 detector.

Abstract We describe the purification of xenon from traces of the radioactive noble gas radon using a cryogenic distillation column. The distillation column was integrated into the gas purification loop of the XENON100 detector for online radon removal. This enabled us to significantly reduce the constant²²²222 Rn background originating from radon emanation. After inserting an auxiliary²²²222 Rn emanation source in the gas loop, we determined a radon reduction factor ofR > 27R > 27 (95% C.L.) for the distillation column by monitoring the²²²222 Rn activity concentration inside the XENON100 detector.

We describe the purification of xenon from traces of the radioactive noble gas radon using a cryogenic distillation column. The distillation column was integrated into the gas purification loop of the XENON100 detector for online radon removal. This enabled us to significantly reduce the constant Rn-222 background originating from radon emanation. After inserting an auxiliary 222Rn emanation source in the gas loop, we determined a radon reduction factor of R > 27 (95% C.L.) for the distillation column by monitoring the Rn-222 activity concentration inside the XENON100 detector.

In this paper, we describe the XENON100 data analyses used to assess the target-intrinsic background sources radon (\\(^{222}\\)Rn), thoron (\\(^{220}\\)Rn) and krypton (\\(^{85}\\)Kr). We detail the event selections of high-energy alpha particles and decay-specific delayed coincidences. We derive distributions of the individual radionuclides inside the detector and quantify their abundances during the main three science runs of the experiment over a period of \\(\\sim\\) 4 years, from January 2010 to January 2014. We compare our results to external measurements of radon emanation and krypton concentrations where we find good agreement. We report an observed reduction in concentrations of radon daughters that we attribute to the plating-out of charged ions on the negatively biased cathode.

We report on the response of liquid xenon to low energy electronic recoils below 15 keV from beta decays of tritium at drift fields of 92 V/cm, 154 V/cm and 366 V/cm using the XENON100 detector. A data-to-simulation fitting method based on Markov Chain Monte Carlo is used to extract the photon yields and recombination fluctuations from the experimental data. The photon yields measured at the two lower fields are in agreement with those from literature; additional measurements at a higher field of 366 V/cm are presented. The electronic and nuclear recoil discrimination as well as its dependence on the drift field and photon detection efficiency are investigated at these low energies. The results provide new measurements in the energy region of interest for dark matter searches using liquid xenon.

We report the first dark matter search results from XENON1T, a \\(\\sim\\)2000-kg-target-mass dual-phase (liquid-gas) xenon time projection chamber in operation at the Laboratori Nazionali del Gran Sasso in Italy and the first ton-scale detector of this kind. The blinded search used 34.2 live days of data acquired between November 2016 and January 2017. Inside the (1042\\(\\pm\\)12) kg fiducial mass and in the [5, 40] \\(\\mathrm{keV}_{\\mathrm{nr}}\\) energy range of interest for WIMP dark matter searches, the electronic recoil background was \\((1.93 \\pm 0.25) \\times 10^{-4}\\) events/(kg \\(\\times\\) day \\(\\times \\mathrm{keV}_{\\mathrm{ee}}\\)), the lowest ever achieved in a dark matter detector. A profile likelihood analysis shows that the data is consistent with the background-only hypothesis. We derive the most stringent exclusion limits on the spin-independent WIMP-nucleon interaction cross section for WIMP masses above 10 GeV/c\\({}^2\\), with a minimum of 7.7 \\(\\times 10^{-47}\\) cm\\({}^2\\) for 35-GeV/c\\({}^2\\) WIMPs at 90% confidence level.

We present the first search for dark matter-induced delayed coincidence signals in a dual-phase xenon time projection chamber, using the 224.6 live days of the XENON100 science run II. This very distinct signature is predicted in the framework of magnetic inelastic dark matter which has been proposed to reconcile the modulation signal reported by the DAMA/LIBRA collaboration with the null results from other direct detection experiments. No candidate event has been found in the region of interest and upper limits on the WIMP's magnetic dipole moment are derived. The scenarios proposed to explain the DAMA/LIBRA modulation signal by magnetic inelastic dark matter interactions of WIMPs with masses of 58.0 GeV/c\\(^2\\) and 122.7 GeV/c\\(^2\\) are excluded at 3.3 \\(\\sigma\\) and 9.3 \\(\\sigma\\), respectively.

We present results of searches for vector and pseudo-scalar bosonic super-WIMPs, which are dark matter candidates with masses at the keV-scale, with the XENON100 experiment. XENON100 is a dual-phase xenon time projection chamber operated at the Laboratori Nazionali del Gran Sasso. A profile likelihood analysis of data with an exposure of 224.6 live days \\(\\times\\) 34\\,kg showed no evidence for a signal above the expected background. We thus obtain new and stringent upper limits in the \\((8-125)\\)\\,keV/c\\(^2\\) mass range, excluding couplings to electrons with coupling constants of \\(g_{ae} > 3\\times10^{-13}\\) for pseudo-scalar and \\(\\alpha'/\\alpha > 2\\times10^{-28}\\) for vector super-WIMPs, respectively. These limits are derived under the assumption that super-WIMPs constitute all of the dark matter in our galaxy.

The XENON1T experiment at the Laboratori Nazionali del Gran Sasso (LNGS) is the first WIMP dark matter detector operating with a liquid xenon target mass above the ton-scale. Out of its 3.2t liquid xenon inventory, 2.0t constitute the active target of the dual-phase time projection chamber. The scintillation and ionization signals from particle interactions are detected with low-background photomultipliers. This article describes the XENON1T instrument and its subsystems as well as strategies to achieve an unprecedented low background level. First results on the detector response and the performance of the subsystems are also presented.