Status of Qupid, a novel photosensor for noble liquid detectors

Abstract The discovery potential of experiments searching for rare events, such as dark matter interaction, relies heavily upon achieving a very low background environment. The current generation of noble liquid dark matter detectors is limited by the radioactivity in the detector materials, mostly from the photomultiplier tubes. Quartz Photon Intensifying Detector (Q upid ) is a novel photosensor based upon hybrid APD technology and with intrinsic radioactivity at least an order of magnitude lower than the presently employed phototubes. The basic concept as well as the status and the prospect of the Q upid are reviewed. The performance of the Q upid as photosensor for the ultraviolet scintillation light of liquid xenon is presented.