Speaker
Description
The NEWS-G collaboration is searching for light dark matter using spherical proportional counters [1]. Access to 50 MeV to 10 GeV mass range is enabled by the combination of single electron threshold, light gaseous targets (H, He, Ne), and highly radio-pure detector construction. Most recently, new constraints on spin-dependent
interactions of dark matter with protons were obtained [2] with the commissioning data of a 140 cm in diameter spherical proportional counter, S140, constructed at LSM using 4N copper with 500 μm electroplated inner layer [3]. The detector currently operates in SNOLAB, with the first physics data-taking campaign recently completed. The latest physics results will be presented along with the recent developments on the detector instrumentation, namely individual read-out of the multi-anode sensor and electroformation techniques. The path towards DarkSPHERE, a large-scale spherical proportional counter fully electroformed underground at the Boulby Underground Laboratory will be discussed [4].
[1] https://arxiv.org/abs/2502.11870
[2] https://arxiv.org/abs/2407.12769
[3] https://arxiv.org/abs/2008.03153
[4] https://arxiv.org/abs/2301.05183