Detector R&D with Negative Ion Gas Mixtures

Negative ion (NI) gas mixtures offer many benefits for directional nuclear recoil detection, including low (near thermal) diffusion and the possibility of adding spin-dependent targets for dark matter (DM) searches. However, the unforeseen benefit of multiple NI species allowing for fiducialization of the drift coordinate might allow for uses beyond directional nuclear recoil detection. In an effort of advancing this field of study, a new NI gas mixture has been identified, argon-SF6. Gaseous avalanche gain and drift velocity results will be presented.