CUPID-0: A double-readout cryogenic detector for Double Beta Decay search

CUPID-0 is the first large mass neutrino-less double beta decay ( 0 ν β β ) experiment based on cryogenic calorimeters with dual read-out of light and heat for background rejection. The detector assembly, consisting of 26 ZnSe crystals, 2 natural and 24 enriched at 95% in 82Se, all coupled with bolometric light detectors, has been constructed respecting very strict protocols and procedures, from the material selection during crystal growth to the new and innovative detector framework, in the attempt to achieve the best performance of the array. The successful construction of the detector lead to promising preliminary results, here presented. The array is in fact taking data underground at LNGS (Italy) since March 2017 and the particle identification, enabled by the light read-out, provides an unprecedented background level, for cryogenic calorimeters, of only 3.2 counts keV − 1 t − 1 yr − 1 in the region of interest of the 0 ν β β search for 82Se, namely around 3 MeV.