  The Argon Dark Matter (ArDM) experiment consists of a liquid argon (LAr) time
projection chamber (TPC) sensitive to nuclear recoils resulting from scattering
of hypothetical Weakly Interacting Massive Particles (WIMPs) on argon targets.
With an active target of 850 kg, ArDM represents an important milestone in the
quest for Dark Matter with LAr. We present the experimental apparatus currently
installed underground at the Laboratorio Subterraneo de Canfranc (LSC), Spain.
We show first data recorded during a single-phase commissioning run in 2015
(ArDM Run I), which overall confirm the good and stable performance of the
ton-scale LAr detector.
