Study of Dark Matter with directionality approach using ZnWO

Low-background anisotropic scintillators represents an innovative approach to study the presence, in the galactic halo, of those Dark Matter (DM) candidate particles able to induce just nuclear recoils, by exploiting the directionality approach. ZnWO4 crystal scintillators are particularly well-suited for such investigations, since the light output and scintillation pulse shape vary depending on the angle of incidence of heavy particles (e.g., α particles and nuclear recoils) relative to the crystal axes. Due to this anisotropic behavior, a signal induced by those DM candidates can be investigated in two independent modes: studying the directionality variation both of the signal rate and of the pulse shape discrimination from the γ/β radiation (that does not give rise to any anisotropic effects). Additionally, the detector’s sensitivity spans a wide range of DM masses, attributed to the differing atomic masses of its target nuclei (Zn, W, and O). Building on these characteristics, the ADAMO project carried out new studies to examine the anisotropic response of ZnWO4 scintillators to α particles and nuclear recoils induced by neutron scattering. A summary of these investigations are presented in this paper.