Abstract and subjects
Discrimination between electron and nuclear recoil events in a liquid argon scintillation detector has been demonstrated with simulations by using the differences in the scintillation photon time distribution between these classes of events. A discrimination power greater than 10
8 is predicted for a liquid argon experiment with a 10
keV threshold, which would mitigate electron and γ-ray backgrounds, including β decays of
39Ar and
42Ar in atmospheric argon. A dark matter search using a ∼2
kg argon target viewed by immersed photomultiplier tubes would allow a sensitivity to a spin-independent WIMP-nucleon cross-section of ∼10
−43
cm
2 for a 100
GeV WIMP, assuming a one-year exposure. This technique could be used to scale the target mass to the tonne scale, allowing a sensitivity of ∼10
−46
cm
2.