The search for light dark matter with the NEWS-G spherical proportional counter

The NEWS-G (New Experiment with Spheres - Gas) collaboration searches for dark matter in the form of low-mass Weakly Interacting Massive Particles (WIMPs) using Spherical Proportional Counters (SPCs) filled with gases with low atomic masses. The operation of SEDINE, a 60-cm diameter prototype SPC filled with a mixture of neon and methane and installed at the Laboratoire Souterrain de Modane (LSM) in France, recently set new constraints on the spin-independent WIMP-nucleon scattering cross-section in the sub-GeV/c(2) mass region. The collaboration is currently planning the installation a 140-cm ultra-low background SPC in a compact shielding at SNOLAB in Canada. Recent advances in radioactive background control, detector monitoring and sensor development, will provide for this next experimental phase of NEWS-G unprecedented sensitivity to low-mass WIMPs.