Speaker
Description
The spherical proportional counter, a novel gaseous detector, has been employed in direct, low-mass particle dark matter (DM) searches thanks to its radiopure material construction, single-electron energy threshold, and flexibility to operate with a range of gases. Gases containing low-mass nuclei such as hydrogen, carbon, and neon are used in the detector to provide good kinematic matching to sub-GeV particle DM. The design of a proposed future experiment, DarkSPHERE, which could be operated in the Boulby Underground Laboratory, is well underway. Gas mixtures containing combinations of He, Ne, CH4, and i-C4H10, intended for use in DarkSPHERE, require characterisation in the detector, for example, measuring electron drift times and gas gains. Measurements of these properties using a UV laser calibration system will be presented, along with comparison to Monte Carlo simulations.