Direct WIMP identification: physics performance of a segmented noble liquid target immersed in a Gd-doped water veto

We evaluate background rejection capabilities and physics performance of a detector composed of two diverse elements: a sensitive target (filled with one or two species of liquefied noble gases) and an active veto (made of Gddoped ultra-pure water). A GEANT4 simulation shows that for a direct WIMP search, this device can reduce the neutron background to O(1) event per year per tonne of material. Our calculation shows that an exposure of one tonne × year will suffice to exclude spin-independent WIMP–nucleon cross sections ranging from 10−9 to 10−10 pb.