Removing krypton from xenon by cryogenic distillation to the ppq level

Abstract

The XENON1T experiment aims for the direct detection of dark matter in a cryostat filled with 3.3 tons of liquid xenon. In order to achieve the desired sensitivity, the background induced by radioactive decays inside the detector has to be sufficiently low. One major contributor is the $\beta$-emitter ${}^{85}$Kr which is an intrinsic contamination of the xenon. For the XENON1T experiment a concentration of natural krypton in xenon ${}^{\mathrm{nat}}$Kr/Xe < 200 ppq (parts per quadrillion, 1 ppq = 10${}^{-15}$ mol/mol) is required. In this work, the design of a novel cryogenic distillation column using the common McCabe-Thiele approach is described. The system demonstrated a krypton reduction factor of 6.4$\cdot$10${}^5$ with thermodynamic stability at process speeds above 3 kg/h. The resulting concentration of ${}^{\mathrm{nat}}$Kr/Xe < 26 ppq is the lowest ever achieved, almost one order of magnitude below the requirements for XENON1T and even sufficient for future dark matter experiments using liquid xenon, such as XENONnT and DARWIN.

References in corpus (11)

• Supersymmetric Dark Matter
• Dark Matter Results from 225 Live Days of XENON100 Data
• Physics reach of the XENON1T dark matter experiment
• LUX-ZEPLIN (LZ) Conceptual Design Report
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• A simple high-sensitivity technique for purity analysis of xenon gas
• Xenon Recirculation-Purification with a Heat Exchanger

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• The XENON1T Dark Matter Experiment
• Projected WIMP Sensitivity of the XENONnT Dark Matter Experiment
• A Next-Generation Liquid Xenon Observatory for Dark Matter and Neutrino Physics
• First observation of two-neutrino double electron capture in ${}^{124}$Xe with XENON1T
• XENON1T Dark Matter Data Analysis: Signal & Background Models, and Statistical Inference
• The XENONnT Dark Matter Experiment
• Material radioassay and selection for the XENON1T dark matter experiment
• Testing sterile neutrino mixing with present and future solar neutrino data
• Online ${}^{222}$Rn removal by cryogenic distillation in the XENON100 experiment
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• Direct Detection of Dark Matter -- APPEC Committee Report
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• CNO Solar Neutrinos in Next-Generation Dark Matter Experiments
• Search for inelastic scattering of WIMP dark matter in XENON1T
• First Search for Light Dark Matter in the Neutrino Fog with XENONnT
• Intrinsic backgrounds from Rn and Kr in the XENON100 experiment
• The XLZD Design Book: Towards the Next-Generation Liquid Xenon Observatory for Dark Matter and Neutrino Physics
• Experimental Analysis of PandaX-4T Cryogenic Distillation System for Removing Krypton from Xenon
• Reactor neutrino liquid xenon coherent elastic scattering experiment
• Design and Commissioning of the PandaX-4T Cryogenic Distillation System for Krypton and Radon Removal
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