arXiv:2601.11837v1 Announce Type: new
Abstract: DarkSide–20k (DS–20k) is a next–generation dual–phase liquid argon (LAr) time projection chamber (TPC) devoted to the direct–detection of dark matter. The detector is currently under construction in Hall–C at the Laboratori Nazionali del Gran Sasso, Italy, at a depth of approximately 3500 m water equivalent. The detector will instrument 49.7~t of low–radioactivity underground LAr contained within an acrylic TPC and is designed to reach a WIMP–nucleon spin–independent cross–section sensitivity down to $10^{-48},mathrm{cm}^{2}$ for a WIMP mass of $0.1,mathrm{TeV}/c^{2}$ in a 200~tonne–year run. In DS–20k a uniform electric drift field is established in the active volume to transport ionization electrons toward the electroluminescence region, with the required high voltage delivered to the TPC cathode through a custom cable and stress–cone assembly. At the University of California, Davis, a dedicated test setup was developed to reproduce the DS–20k cathode high–voltage connection in LAr, matching the local electric–field conditions. This work summarizes the results of a comprehensive test campaign validating the operation of the DS–20k cathode HV system in LAr up to $-100$~kV.