  DarkSide (DS) at Gran Sasso underground laboratory is a direct dark matter
search program based on TPCs with liquid argon from underground sources. The
DS-50 TPC, with 50 kg of liquid argon is installed inside active neutron and
muon detectors. DS-50 has been taking data since Nov 2013, collecting more than
10^7 events with atmospheric argon. This data represents an exposure to the
largest background, beta decays of 39Ar, comparable to the full 3 y run of
DS-50 with underground argon. When analysed with a threshold that would give a
sensitivity in the full run of about 10^-45 cm2 at a WIMP mass of 100 GeV,
there is no 39Ar background observed. We present the detector design and
performance, the results from the atmospheric argon run and plans for an
upscale to a multi-ton detector along with its sensitivity.
