Crystal Scintillators for the Dark Matter Directionality Approach

Low background anisotropic detectors can offer a unique way to study those dark matter (DM) candidate particles able to induce nuclear recoils through the directionality technique. This approach is based on studying the correlation between the nuclear recoils’ direction and the Earth motion in the galactic rest frame. Thanks to the anisotropic features of such detectors, a signal, induced by the DM candidates, is expected to change with a particular behaviour as a function of the sidereal time. The ZnWO _4 has unique features and it is an excellent candidate for the purposes. Both the light output and the scintillation pulse shape depend on the impinging direction of heavy particles (p, α , nuclear recoils, etc.) with respect to the crystal axes and can supply two independent modes to study the directionality and to discriminate the γ/β radiation (that does not give rise to any anisotropic effects). In this work, the measurements to study the anisotropic response of a ZnWO _4 scintillation detector to α particles and to nuclear recoils, induced by neutron scattering, are briefly summarised.