Abstract

The absence of a direct observation of dark matter has prompted interest in ever lower-mass candidate particles.The NEWS-G experiment aims to shed light on this sector by utilising a novel gaseous detector, the spherical proportional counter. The combination of low energy threshold, low-radioactivity construction techniques and low-mass gas targets (H, Ne) allow competitive sensitivities to sub-GeV/c2 dark matter particles. The current status of the experiment will be presented, including previous results produced by the 60 cm diam. SEDINE detector, based in the Underground Laboratory of Modane(LSM), France. The next generation of NEWS-G detector - a 140 cm diam. spherical proportional counter constructed using 4N copper - is currently undergoing its commissioning and first data taking phase at LSM, and will soon be moved for the SNOLAB underground laboratory in Canada. The experiment will be presented, including the ultra-low radioactivity electroplating techniques used in its construction, as well as the instrumentation developments carried out. Finally, the future prospects of spherical proportional counters for direct dark matter searches will be discussed.