Karlsruhe 2024 – scientific programme

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T: Fachverband Teilchenphysik

T 121: Search for Dark Matter 6

T 121.6: Talk

Friday, March 8, 2024, 10:15–10:30, Geb. 30.35: HSI

Coating based radon barriers for future liquid xenon detectors — •Florian Jörg, Giovanni Volta, and Hardy Simgen — Max-Planck-Institut für Kernphysik Heidelberg, Germany

Dual-phase liquid xenon time projection chambers have become a leading technology in the search for dark matter. These detectors must be operated under extremely low radioactive background conditions. Especially, the radioactive noble gas ²²²Rn, that is constantly released from material surfaces, must be suppressed to the level of only a few atoms.

We have been investigating techniques to suppress its release by sealing surfaces with thin coating layers. A thousandfold reduction of the radon release has been demonstrated on a 2×2 cm²-small stainless steel sample, that has been implanted with ²²⁶Ra at the ISOLDE facility at CERN. Following on the successful small-scale tests, the setup underwent an upgrade which allows coating of larger vessel-like samples. Besides the radon tightness of the coating layers, also their intrinsic radiopurity is now being assessed and first results will be shown.

Keywords: Liquid xenon (LXe); Time projection chambers (TPC); Radon mitigation; Low background physics; Surface coatings