Cryogenic UV photomultipliers for Dark-Matter

WIMPs, one of the most promising Dark Matter candidates, are currently searched for through their interaction with large-mass liquid-Xenon target (e.g. the new XENON1t experiment). They are expected to produce a distinctive scintillation signal. The success of the Dark Matter quest critically depends on the reduction of background signals in the detector system and on the efficiency of detecting the very very weak WIMP-induced scintillation signals resulting from few-keV nuclear recoils. We have been developing novel detector concepts for the future generation of very large mass noble-liquid detectors (e.g. several tens of tonns in DARWIN). Among them are cryogenic Gaseous Photomultipliers (GPM), composed of cascaded-THGEM elements - potential replacement of current PMTs in dual-phase TPCs. More exotic are Liquid Hole Multipliers (LHM), consituting "local dual-phase" photon and electron multipliers in single-phase TPCs. See details in the "basic research" paragraph.