Characterization of electroluminescence signal in the Liquid Argon TPC of the ReD experiment

Dark Matter as a Weakly Interactive Massive Particle (WIMP) has been directly searched in the past decade at a mass scale from 100 GeV/c2 up to 1 TeV/c2. Double-phase argon Time Projection Chambers (LAr TPC) recently explored the possibility of inspecting also the GeV/c2 scale looking for a lighter WIMP using the ionization signal only. These studies are limited by the fact that the ionization response of argon is scarcely described for recoil energies of a few keV. The ReD experiment within the DarkSide-20k Collaboration aims to investigate the liquid argon ionization response at 2-5 keV to cover the current gap.