Development of ZnWO4 crystal scintillators for rare events search

The ZnWO4 crystal scintillator is a promising detector for low counting experiments thanks to the high level of radiopurity and reasonably high optical and scintillation properties. In particular, ZnWO4 scintillators can be utilized in the searches for double beta processes, in the investigation of rare alpha decays and Dark Matter. In fact, one of its main characteristics is to be an anisotropic detector. In the case of interaction of heavy particles or nuclear recoils, the light output and the time profile of the scintillation pulse depend on the direction of the particles with respect to the crystal axes; no difference is observed for γ/β radiation. These anisotropic features can offer a unique possibility to exploit the so-called directionality approach in order to investigate the presence of the Dark Matter candidates which induces nuclear recoils. In fact, their use can overcome the difficulty of detecting extremely short nuclear recoil traces.