Search for rare processes with ZnWO₄crystal scintillators

Abstract

Abstract. Radiopure ZnWO 4 crystal scintillators with mass (0.1-0.7 kg) have been developed and put in measurement in the Gran Sasso National Laboratories of the INFN to search for rare processes. The radioactive contamination of the crystals have been estimated and the double beta decay of zinc and tungsten isotopes was searched for, reaching a sensitivity at the level of 10 18 − 10 21 yr; in addition a new half-life limit on alpha transition of 183 W to the metastable excited level of 179 Hf has also been obtained. The achieved radiopurity of the ZnWO 4 crystals make them very promising detectors for ββ decay investigations while their anisotropic features make them very interesting detectors to investigate dark matter particles directionality.