doi:10.1088/1742-6596/718/4/042026engIguaz, F JGarza, J GAznar, FCastel, J FCebrián, SDafni, TGarcía, J AIrastorza, I GLagraba, ALuzón, GPeiró, ATREX-DM: a low background Micromegas-based TPC for low-mass WIMP detectionART-2016-95708Dark Matter experiments are recently focusing their detection techniques in low- mass WIMPs, which requires the use of light elements and low energy threshold. In this context, we describe the TREX-DM experiment, a low background Micromegas-based TPC for low-mass WIMP detection. Its main goal is the operation of an active detection mass ~0.3 kg, with an energy threshold below 0.4 keVee and fully built with previously selected radiopure materials. This work describes the commissioning of the actual setup situated in a laboratory on surface and the updates needed for a possible physics run at the Canfranc Underground Laboratory (LSC) in 2016. A preliminary background model of TREX-DM is also presented, based on a Geant4 simulation, the simulation of the detector’s response and two discrimination methods: a conservative muon/electron and one based on a neutron source. Based on this background model, TREX-DM could be competitive in the search for low-mass WIMPs. In particular it could be sensitive, e.g., to the low-mass WIMP interpretation of the DAMA/LIBRA and other hints in a conservative scenario.2016http://zaguan.unizar.es/record/5636310.1088/1742-6596/718/4/042026http://zaguan.unizar.es/record/56363oai:zaguan.unizar.es:56363info:eu-repo/grantAgreement/EC/FP7/240054/EU/Novel Developments in Time Projection Chambers (TPCs) for Rare Event Searches in Underground Astroparticle EXperiments/TREXinfo:eu-repo/grantAgreement/ES/MINECO-FEDER/FPA2011-24058info:eu-repo/grantAgreement/ES/MINECO/FPA2013-41085-PJournal of Physics: Conference Series 718 (2016), 042026 [5 pp.]byhttp://creativecommons.org/licenses/by/3.0/es/info:eu-repo/semantics/openAccess