ZnWO₄ anisotropic scintillator for Dark Matter investigation with the directionality technique

¹ Dip. di Fisica, Università di Roma Tor Vergata, I-00133 Rome, Italy
² INFN, sez. Roma Tor Vergata, I-00133 Rome, Italy
³ INFN, Laboratori Nazionali del Gran Sasso, I-67100 Assergi (AQ), Italy
⁴ Institute for Nuclear Research, MSP 03680 Kyiv, Ukraine
⁵ INFN, sez. Roma, I-00185 Rome, Italy
⁶ CSNSM, Univ. Paris-Sud, CNRS/IN2P3, Université Paris-Saclay, 91405 Orsay, France

Published online: 23 March 2017

Abstract

The ZnWO₄ crystal scintillator has unique features that make it very promising to realize a pioneering experiment to pursue Dark Matter investigation with the directionality technique. In particular in this detector the light output and the scintillation pulse shape for heavy particles (p, α, nuclear recoils) depend on the direction of the impinging particle with respect to the crystal axes, while the response to γ/β radiation is isotropic. The anisotropy of the light output can be considered to point out the presence in the diurnal counting rate of a Dark Matter signal produced by candidate particle inducing just nuclear recoils. In addition this crystal detector has also other important characteristics for a Dark Matter experiment: high light output, high level of radiopurity. In this paper the present performances of the developed ZnWO₄ crystal scintillator will be summarized together with the possible future improvements. Some reachable sensitivities – under given assumptions – in the investigation of DM candidate particles with the directionality technique will also be addressed.