DarkSide-50 is the first physics detector of the DarkSide family, featuring a two-phase underground-argon Time Projection Chamber (50 kg sensitive mass) surrounded by an organic liquid scintillator veto (30 tonnes) and a muon water-Cherenkov detector (1000 tonnes). The two-phase detector is currently operating at Gran Sasso underground laboratory, fully shielded and filled with research grade atmospheric argon. This first run, with regular argon, is focused on the study of the detector response and its performance in background suppression, exploiting the high rate from 39Ar to collect in a few days the electron recoil background statistics expected in few years of data taking with underground, low-radioactivity argon. First results on the measured sub-detectors performances and background rejection power will be reported.
