Performance of ZnMoO₄crystal as cryogenic scintillating bolometer to search for double beta decay of molybdenum

Abstract

Zinc molybdate (ZnMoO4) single crystals were grown for the first time by the\nCzochralski method and their luminescence was measured under X ray excitation\nin the temperature range 85-400 K. Properties of ZnMoO4 crystal as cryogenic\nlow temperature scintillator were checked for the first time. Radioactive\ncontamination of the ZnMoO4 crystal was estimated as <0.3 mBq/kg (228-Th) and 8\nmBq/kg (226-Ra). Thanks to the simultaneous measurement of the scintillation\nlight and the phonon signal, the alpha particles can be discriminated from the\ngamma/beta interactions, making this compound extremely promising for the\nsearch of neutrinoless Double Beta Decay of 100-Mo. We also report on the\nability to discriminate the alpha-induced background without the light\nmeasurement, thanks to a different shape of the thermal signal that\ncharacterizes gamma/beta and alpha particle interactions.\n