Speaker
Description
Liquid argon (LAr) scintillator-based detectors are used to search for WIMP dark matter by looking for light emission from WIMP-nucleon interactions in the target volume. The DEAP-3600 LAr dark matter detector has operated since 2016 at SNOLAB in Sudbury, Canada, and has previously contained 3.3 tonnes of LAr scintillator target. It has a background rate below one event per tonne-year, and set the leading limit on the WIMP-nucleon spin-independent cross section on an LAr target at 3.9 × 10$^{-45}$ cm$^{2}$ (1.5 × 10$^{-44}$ cm$^{2}$) for a 100 GeV/c$^{2}$ (1 TeV/c$^{2}$) WIMP mass at a 90$\%$ C.L. Other results include a relative measurement of the $\alpha$-particle scintillation quenching factor for LAr at MeV energy, and a measurement of the $^{39}$Ar half-life that provided a result of 302 ($\pm$8$_{stat}$ $\pm$6$_{sys}$) years- in conflict with previously accepted values. The next generation LAr dark matter detector, DarkSide-20k (DS-20k), is currently being constructed by an international collaboration in Gran Sasso, Italy. DS-20k will hold an active target volume of 50 tonnes (inner fiducial volume of 20 tonnes) of LAr, and employ a dual-phase time projection chamber (TPC) to enable additional analysis methods. Its projected sensitivity is 6.3 × 10$^{-48}$ cm$^{2}$ for a 1 TeV/c$^{2}$ WIMP mass at a 90$\%$ C.L. over its expected 200 tonne-year exposure, and its projected background rate is also below one event per tonne-year. Both DEAP-3600 and Darkside-20k, beyond detecting dark matter, aim to improve LAr detector technology for use in the proposed ARGO detector.
