Operating a large-diameter dual-phase liquid xenon TPC in the unshielded PANCAKE facility

Julia Müller; Jaron Grigat; Robin Glade-Beucke; Sebastian Lindemann; Tiffany Luce; Gnanesh Chandra Madduri; Jens Reininghaus; Marc Schumann; Adam Softley-Brown; Andrew Stevens

arXiv · 2601.15938

Operating a large-diameter dual-phase liquid xenon TPC in the unshielded PANCAKE facility

Julia Müller·Jaron Grigat·Robin Glade-Beucke·Sebastian Lindemann·Tiffany Luce·Gnanesh Chandra Madduri·Jens Reininghaus·Marc Schumann·Adam Softley-Brown·Andrew Stevens

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Abstract

Future liquid-xenon (LXe) based observatories for rare processes, such as XLZD, require testing of large components and sub-assemblies in cryogenic liquid or gaseous xenon environments. Here we present results from the stable operation of a shallow dual-phase LXe TPC with an inner diameter of 133.4\,cm and a height of 3.1\,cm in the unshielded PANCAKE platform, without underground suppression of cosmic-ray backgrounds. A total of 340\,kg of xenon was used in the experiment, of which 127\,kg constituted the active TPC mass. Measurements of the LXe purity-dependent electron lifetime and the electron drift velocity in LXe demonstrate that sensitive measurements to characterize the TPC performance are possible in a high-background environment, even with a very basic PMT-based light detection system. Improving this will straightforwardly reduce the TPC threshold, which was observed to be around 15\,keV for electronic recoils in TPC operation.

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Julia Müller, Jaron Grigat, Robin Glade-Beucke, Sebastian Lindemann, Tiffany Luce, Gnanesh Chandra Madduri, Jens Reininghaus, Marc Schumann, Adam Softley-Brown, Andrew Stevens. 2026-01-22. Operating a large-diameter dual-phase liquid xenon TPC in the unshielded PANCAKE facility. https://arxiv.org/abs/2601.15938

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