GEANT4 based design to measure the solubility of tritiated molecules in dual phase xenon

Detection of trace amounts of tritium is a challenging task that can be tackled using scintillation. Liquid xenon is an excellent scintillator for this purpose. A fundamental property in designing analytical systems for tritium detection is the solubility of tritiated molecules. Trace detection of tritium is critical for experiments aimed at the detection of rare physical interactions, such as the direct detection of dark matter, where naturally occurring tritium background is a challenge to overcome. Consequently, systems for both detection and removal of tritium are required. The aim of the "Tritium in Xenon" (TriXe) experiment is to determine the Henry solubility and the diffusion constant of tritiated hydrogen, water and methanes in dual-phase xenon in thermal equilibrium. TriXe employs a dual-phase chamber in which the xenon is present at operating conditions of DARWIN. By detecting VUV scintillation light with photomultipliers, the concentration of the tritiated molecules in each phase can be determined, as the concentration is proportional to the counting rate. Together with the second diffusion law, the diffusion constant can be deduced from the change in the count rate over time. ... mehrThe results of TriXe can be used to make qualitative and quantitative suggestions for changes in background reduction and direct tritium monitoring by cryogenic distillation.