Claudio Savarese (Princeton University)
The DarkSide programme aims to a WIMP direct detection using a dual phase argon time projection chamber. The next generation experiment, DS-20k, will be a detector in excess of 20 tonnes of fiducial mass. A pivotal aspect to the sensitivity of the experiment is its light detection technology. The DarkSide collaboration decided to adopt a new family of photo-sensors called Silicon Photomultipliers (SiPMs). The talk will introduce the design of a DarkSide Photo Detector Module (PDM), a 25cm^2 array of SiPMs read-out as a single channel. The PDM’s performances in terms of photon detection efficiency, dark count rate, and correlated noises will be outlined, including an overview of the detailed characterisation of the detector’s signal-to-noise ratio and its time resolution. Then the signal extraction strategies will be discussed, focusing on the optical analog cryogenic transmission using radiopure fibers immune to electronic noise injection in the detector. Finally, an overview of the silicon packaging strategies adopted by the DarkSide collaboration will be introduced with attention to the mass-production of the 13000 PDMs, to the material selection and to the high radiopurity result achieved.
Collaboration DarkSide (LNGS)