New Experiments With Spheres-Gas ( NEWS-G ) is a direct dark matter detection experiment using Spherical Proportional Counters ( SPCs ) with light noble gases to search for low-mass Weakly Interacting Massive Particles ( WIMPs ) .
We report the results from the first physics run taken at the Laboratoire Souterrain de Modane ( LSM ) with SEDINE , a 60 cm diameter prototype SPC operated with a mixture of Ne + \mathrm { CH } _ { 4 } ( 0.7 % ) at 3.1 bars for a total exposure of 9.7 \mathrm { kg \cdot days } .
New constraints are set on the spin-independent WIMP-nucleon scattering cross-section in the sub- \mathrm { GeV / c ^ { 2 } } mass region .
We exclude cross-sections above 4.4 \times \mathrm { 10 ^ { -37 } cm ^ { 2 } } at 90 % confidence level ( C.L . )
for a 0.5 \mathrm { GeV / c ^ { 2 } } WIMP .
The competitive results obtained with SEDINE are promising for the next phase of the NEWS-G experiment : a 140 cm diameter SPC to be installed at SNOLAB by summer 2018 .